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HomeMy WebLinkAboutDay, Etiwanda & San Sevaine Drainage Plan Vol I 00016 REPORT ON THE DAY ETI WA NDA & SAN SEVA I NE CREEKS SYSTEM DRAINAGE PLAN VOLUME I HYDROLOGIC &HYDRAULIC DESIGN CRITERIA DISCUSSION OF PLAN CONSTRUCTION COST ESTIMATES SAN BERNARDINO COUNTY FLOOD CONTROL DISTRICT MARCH, 1983 BILL MANN & ASSOCIATES 1814 COMMERCENTER WEST SUITE A SAN BERNARDINO, CA 92408 c REPORT ON THE DAY, ETIWANDA AND SAN SEVAINE CREEK DRAINAGE PLAN VOLUME I HYDROLOGIC AND HYDRAULIC DESIGN CRITERIA DISCUSSION OF PLAN CONSTRUCTION COST ESTIMATES 1 Prepared for the San Bernardino County Flood Control District In Conjunction With City of Rancho Cucamonga City of Ontario , City of Fontana Riverside County Flood Control and Water Conservation District March, 1983 By Bill Mann & Associates 1814 Commercenter West, Suite A San Bernardino, CA 92408 TABLE OF CONTENTS • Page REPORT SUMMARY SECTION I. INTRODUCTION AND SCOPE 1 SECTION II. HYDROLOGIC DESIGN CRITERIA 6 SECTION III. HYDRAULIC DESIGN CRITERIA 18 SECTION IV. DEBRIS DAM AND BASIN DESIGN CRITERIA 32 SECTION V. DISCUSSION OF PLAN 38 1. GENERAL 38 2, DAY CREEK SYSTEM 42 A. GENERAL 42 B. DAY CREEK DEBRIS DAM 43 C. DAY CREEK CHANNEL 45 1) DEBRIS DAM TO HIGHLAND AVENUE 45 2) HIGHLAND AVENUE TO DEVORE FREEWAY 46 3) DEVORE FREEWAY TO SAN BERNARDINO 49 FREEWAY 4) SAN BERNARDINO FREEWAY TO WINEVILLE 52 BASIN 5) WINEVILLE BASIN TO RIVERSIDE BASIN 55 6) RIVERSIDE BASIN TO POMONA FREEWAY 56 D. LOWER ETIWANDA CREEK CHANNEL 59 3. SAN SEVAINE CREEK SYSTEM 62 A. GENERAL 62 B. ETIWANDA DEBRIS DAM AND CHANNEL 63 C. SAN SEVAINE CREEK - CANYON MOUTH TO 65 SUMMIT AVENUE D. SAN SEVAINE CREEK - SUMMIT AVENUE TO 67 DEVORE FREEWAY E. SAN SEVAINE CHANNEL - DEVORE FREEWAY 69 TO SAN BERNARDINO RIVERSIDE COUNTY LINE 1) DEVORE FREEWAY TO BASELINE AVENUE 70 2) BASELINE AVENUE TO FOOTHILL BLVD. 72 3) FOOTHILL BLVD TO WEST FONTANA 73 CHANNEL (SFRR) 4) WEST FONTANA CHANNEL TO SAN BERNAR- 75 DINO FREEWAY 1 i 1 MMOMIMMMMMOWNW 1 1 TABLE OF CONTENTS 1 Page 1 (CONTINUED) 5) SAN BERNARDINO FREEWAY TO 80 JURUPA BASIN 6) JURUPA ;BASIN 82 7) JURUPA BASIN TO SAN BERNARDINO- 84 1 RIVERSIDE COUNTY LINE SECTION VI. CONSTRUCTION COST ESTIMATES 86 1 SECTION VII, CONSTRUCTION SEQUENCE 94 1 1 ' APPENDIX - 1. REFERENCES 2. HYDROLOGIC ANALYSIS 1 1 1 1 1 ii 1 . : ' .r : Y Y -..` i, r"-'`...' r'i �.. N 'n••"{ • _ _ f ,... d ..A -t .. - ' y({ " + y�� � y � . q. f �' Y t t ' p' . . ( r '1 , - y � t 4 1 1 4E q . As Y ."' ' T 4 ' . ' 1 ' , �Si ° y .-.+ } , . _{ , k+ 'K" s • .i +i,••'• . "I— a ' ^: r = i • 3 � r ' t- . •. ' - ., , ,t ` ` ., z •A A S ` ' w " S '"- .�' . 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',.. ^ � � i . a a , et „ • , ! ■ IN 9.' \ , • � - y . "� L.1 .. I R• j ° f J- " °,+ , i Y ' a s 7 tl " i �S � ,.- it' ",„ ,. „,,, 0, \ • ' ...- - 7: , , E4A lif iii, • 7 � .w,Y� "RrP.�,,7 ^... ': 44 ' ., • 4 7 r, ,...' : ..):::' : .."1.ii - %. ,-.1't 'd•' .i.. � io ' .. i ji)kir ti.._ ' �' �. t 4 b 7 � a rr, , r ,� �. P r(, }, fi ,� '� � a '3 C� a +, 1..C'': ... \ .1100 �,- �� • : [ �' '� �'� ` �, \ ��•� f i1 _ -— o .y " "A.. - . > � r.. +r ..,,..:., i ., .. f ,;.#,,,,,, /�..,.,� , `'".'' z �, ' PROPOSED CHANNEL.- H. \j . . . ,-„„_. ,.: if 66 tH ` ��, e ~ E T FL.OWPATH -- -- -- ` AV I S \ d � % �� 1 i� t o .--1 �' :. if s I ; i, � , «'., ; aa , . .�1. I ' N 3 '• x DA ETIWANDA /SAN,., .E # , „ � . R EKS ` �� x. N ` �l// I j 1 �J, % : ,. •4 x� r , +,. a,�f W +n' J y ` °' "mil. Sa\ \L 3... ^ . >wI 7F � � ''' - ,-" 3., .'-1'-'`:' w r �� „,� 81..L .N Y � a -r ,z The Drainage Plan lan was developed primarily for two reasons. Due to the proposed development in the upper watershed and inadequate downstream facilities, the development industry and involved agencies are concerned with potential damage down- stream due to increased runoff that will be generated from development. Additionally, a large part of the developing area is subject to flood hazards due to the lack of adequate flood protection facilities. There is also a need to develop a water conservation plan that can be coordinated with all of the affected agencies. In general, the Day Creek and San Sevaine Creek Channels exist for the most'part as inadequate earth channels. Several reaches of Etiwanda Creek exist only as a natural drainage course. In one location, San Sevaine Creek flows are carried in a street, subjecting the community to overflow and debris deposition during major storm flows. Figure No 2 shows the overflow area for the 1969 flood in San Bernardino County. The overflow map shows the severity of over- flow from that major storm. In addition to possible flood damage to the overflow area, the existing channels are crossed by freeways, main line railroads, and major water and gas trans- mission lines. Most of the major transportation arteries and utility systems are subject to damage during major floods. Various elements of the overall Drainage Plan are covered in other supplemental reports. Water conservation is an important element of the Drainage Plan and the water supply for the general area. A detailed analysis of water conservation is covered under the supplemental report entitled "Day, Etiwanda and San Sevaine Creek Drainage Plan, Water Conservation Element ". The water conservation report includes plansfor water conservation basin I s 1 development and providesan estimate of local urban runoff and storm flows that can be retained and percolated into the under- ground water table. As an adjunct to the Day, Etiwanda and San Sevaine Creek Drainage Plan, an application to the Bureau of Reclamation is being prepared for long term loan and grant 1 funding for a portion of the Day Creek Channel System. An application project report and environmental impact statement to support the funding request is being prepared under the Bureau of Reclamation's Small Reclamation Projects Act of 1956. i A separate preliminary report on "Funding Mechanisms for the Day, Etiwanda and San Sevaine Creek Drainage Plan" provides a preliminary financial analysis for construction of the Drainage Plan. Although the financial analysis is preliminary in nature and will not preclude the need for an indepth financial analysis and plan, it will provide the basic framework for the final financial plan. C HYDROLOGIC DESIGN CRITERIA The methodology and peak runoff flows for the Drainage Plan were developed by the consulting firm of Williamson & Schmid in conjunction with Bill Mann & Associates, the San Bernardino County Flood Control District, and Riverside County Flood Con- trol and Water Conservation District. The hydrology report entitled "A Hydrologic Analysis of the Day Creek /San Sevaine Creek Watersheds in the County of San Bernardino" dated June, 1982, is included in the Appendix in its entirety. The details of the hydrologic design criteria used in the development of i the preliminary plans is covered in Section II of this report. The design storm frequency for a 100 - year event was used in developing design flows for the flood channels. The unit hydro - C 4 graph method was used in this analysis and report. v c With the exception of the Day Creek Basin immediately south of Highland Avenue, basin storage of flood flows was not considered for the ultimate design on the Day Creek Channel System. Wine- ; ville and Riverside Basins will be used to some degree for flood flow storage in the early phases of channel construction. In the San Sevaine Creek Channel System, the Lower San Sevaine Basin and Jurupa Basin were used as flood storage basins. Lower San Sevaine Basin is designed as a flow- through basin and Jurupa Basin is designed as a by -pass system. Design flows were reduced below these basins based on analysis and coordination with the San Bernardino County Flood Control District, and the Riverside County Flood Control and Water Conservation District. Tabulation of channel design flows by reach for each system are given in Section II. The Drainage Plan and hydrology map show the watershed area, design flows, and basin storage values. Figure No. 1 shows schematically the location of the proposed basins. P HYDRAULIC DESIGN CRITERIA The design flow for the flood control systems described herein irr is based on a 100 -year frequency storm. The hydraulic design ,.. criteria is described in detail in Section III. In general, 6 hydraulic methods and design criteria used in developing the Po preliminary plans were based on the Los Angeles County Flood Control District's experiences and practices, and is recommended herein. Water surface profile calculations for final design plans should be calculated using the Bernoulli energy equation combined with the momentum equation for analyzing confluences and junctions. ,�. A three foot (3') freeboard was used for the channel design where the flow velocity was 35 feet per second or more. A two foot (2') 6 vi Pm c freeboard was used for channel reaches where the flow velocity was 35 feet per second or less. DISCUSSION OF PLAN A. GENERAL As indicated above, under the storm drain plan for Day, Etiwanda and San Sevaine Creeks presented herein, the ap- proximate 82 square mile study area will be drained by two major channel systems. These two major systems are the Day Creek System and the San Sevaine Creek System. The proposed systems are shown in schematic form on Figure No. 1 and the hydrology map in the packet of this report. The drainage plan and hydrology map included in this report show the overall drainage boundary, the sub - system drainage areas, the design flows, and the major channel system. The Upper Etiwanda Creek drainage area flows will ultimately be directed to the San Sevaine Creek System at the Devore Freeway. A debris dam below the mouth of Etiwanda Canyon and a concrete lined channel from the canyon mouth to the existing channel under the Devore Freeway is proposed. A concrete lined channel from the existing channel under the Devore Freeway to the Santa Ana River will provide for the combined Upper Etiwanda Creek,, San Sevaine Creek, and all tributary flows to San Sevaine Creek. The Lower Etiwanda Creek flows will be directed to the Day Creek System. A concrete lined channel for Lower Etiwanda Creek flow is proposed from the San Bernardino Freeway to Wineville Basin. The Day Creek System extends from the Day vii g Creek canyon mouth to Wineville and Riverside Basins and ultimately to the Santa Ana River. The systems are shown on the drainage plan and hydrology map and are discussed in detail in Section V of this report. Figure No. 1 shows the flood control systems schematically. The drainage plan and hydrology map is enclosed in the packet of this report. B. DAY CREEK CHANNEL SYSTEM 1. General The Day Creek Channel System, including Lower Etiwanda Creek, has a total drainage area of approximately 22 square miles at Riverside Basin. The Drainage Plan map is included in this report and shows the proposed system alignment, total drainage area, sub - system drainage areas, and the system design flows at . various points along the route. study and report includes that The drainage st y portion of p P the system in Riverside County from Riverside Basin to the Pomona Freeway. This plan connects to and coordinates with the Riverside County Flood Control and Water Conser- vation District's Drainage Plan immediately south of the Pomona Freeway. Lower Etiwanda Creek Channel, from Wineville Basin to the San Bernardino Freeway, is con- sidered to be part of the Day Creek Channel System. The Day Creek Channel System includes the Day Creek Spreading Grounds, Day Creek Basin, and Wineville and Riverside Basins, all important water conservation facilities. These facilities will provide important elements for conserving of urban runoff and storm flows for the watershed areas and provide retention of increased runoff from development as the area develops. c viii C. DAY CREEK DEBRIS DAM The drainage area for Day Creek at the canyon mouth is approximately 3,042 acres (4.75 square miles). A debris dam with a storage capacity of approximately 500,000 cubic yards of debris is proposed (based on 100,000 cubic yards ' of debris per square mile of drainage area). The debris dam has a preliminary design height of approximately 55 feet. The Cucamonga County Water District has intake tunnels located in the canyon mouth that intercept low flows and groundwater. Because of these intake facilities, the debris dam site was located below the canyon mouth. An additional constraint on the location of the dam site is the Cucamonga Fault Zone located above the powerlines. A "Reconnaissance Geotechnical Investigation" report has been prepared. The reconnaissance report is on file in the Flood Control District office. The report recommends a structure setback from the fault of 75 feet south of the defined fault zone and 400 feet north of the fault zone. The preliminary dam site has been located above the recommended setback line and 1 below the Cucamonga County Water District water intake facilities. A detailed geotechnical and soils investigation 1 is recommended during the design stage for final dam siting and design criteria. 1 The preliminary debris dam site is shown on the drainage plan and hydrology map and on the preliminary plan and 1 profile sheets. The plan and profile sheets are in Volume II of this report. 1 1 1 ix 1 D. SAN SEVAINE CREEK CHANNEL SYSTEM 1. General The San Sevaine Creek Channel System, including Upper Etiwanda Creek, has a total drainage area of approxi- mately 60 square miles at the Pomona Freeway. The drainage plan and hydrology map is included in this report and shows the proposed system alignment, total drainage area, sub - system drainage areas, and the system design flows at various points along the route. For purposes of this report, the lower end of the drainage area is shown at the Pomona Freeway, just south of the San Bernardino - Riverside County Line. That portion of the San Sevaine Creek Channel in Riverside County has been designed by the Riverside County Flood Control and Water Conservation District and is covered in a separate report. However, the two plans have been coordinated. The Upper Etiwanda Creek Channel, from the canyon mouth to the existing channel under the Devore Freeway, is included in the San Sevaine Creek Channel System. The proposed plan calls for confluencing Etiwanda Creek and San Sevaine Creek flows at the downstream end of the existing parallel concrete lined channels under the Devore Freeway. Refer to the plan and profile sheets in Volume II of this report for the location of the existing channels and the proposed connection points. 2. Etiwanda Debris Dam and Channel The drainage area for Etiwanda Creek at the canyon mouth is approximately 1,953 acres (3.05 square miles). A debris dam with a storage capacity of approximately 300,000 x Ian cubic yards of debris is proposed (based on 100,000 cubic yards of debris per square mile of drainage area). The debris dam has a preliminary design height of 45 feet. Because of the Cucamonga Fault Zone, the proposed dam site is located below the canyon mouth. A "Reconnais- sance Geotechnical Investigation" report has been pre- pared and is on file in the Flood Control District office. The report recommends a structure setback line from the fault of 75 feet south of the defined fault zone to 400 feet north of the fault zone. This limita- tion requires a dam siting south of the canyon mouth, north of the powerline. A detailed geotechnical and soils investigation is recommended during the design stage for final dam siting and design criteria. Because of the fault zone and the lack of confinement of flows, the final siting and design of the dam site will be difficult. The preliminary debris dam site is shown on the drainage plan and hydrology map and the preliminary plan and profile sheets in Volume II of this report. 3. San Sevaine Creek - Canyon Mouth to Summit Avenue The drainage area for San Sevaine Creek at the canyon mouth is approximately 1,273 acres (1.99 square miles). The recommended plan does not include a debris dam and concrete channel for San Sevaine Creek flows above the Devore Freeway. However, a debris dam and concrete lined channel is shown on the plans as an alternative. Because of the extensive spreading grounds and storage basins available above the Devore Freeway, the recommended xi g plan for San Sevaine Creek is a reception type levee from the canyon mouth to Summit Avenue. DEBRIS DAMS AND BASINS Consideration of debris loading transported by streams below mountain and foothill areas is essential in planning and design of flood control facilities. This is especially true in the immediate years after a watershed burn. Failure to provide either debris storage basins or additional hydraulic capacity for debris bulked flows can seriously affect the performance of flood control facilities and /or make them inoperable. • Section IV describes the design criteria for the proposed debris k i dams, spillways and outlet works. Because of the experience the Los Angeles County Flood Control District has had with debris movement and storage in the San Gabriel Mountain watershed, its criteria was used for the preliminary design. At such time as the construction plans are prepared, a more detailed debris production analysis will be necessary. It is recommended the U. S. Corps of Engineers methodology for debris dam design also be investigated. A detailed geotechnical and soils investiga- tion and report will be necessary for each proposed debris dam siting. The Cucamonga Fault System, which crosses the area just southerly of the toe of the mountains, further complicates the debris dam siting and analysis. In general, the debris dam sizing was based on a preliminary design storage volume of 100,000 cubic yards of debris per square mile of drainage area. The .dam spillway for the pre- liminary plans was based on Los Angeles County Flood Control District criteria. The final design plans should be based on c xii c passing a capital flood with adequate freeboard to assure the dam will not be overtopped. The recommended plan calls for a debris dam for Day Creek' Canyon and Etiwanda Creek Canyon. Because of the extensive spreading grounds and flood storage basins proposed below San Sevaine Canyon, a debris dam is not recommended for that canyon. An alternate plan with a debris dam is included in the preliminary plans. The schematic location of the proposed debris dams are shown on Figure No. 1. The debris dam preliminary siting, Cucamonga Fault System, and recommended structure setback lines are shown on the preliminary plans included in Volume II of this report. CONSTRUCTION COST ESTIMATES FOR THE DAY CREEK AND SAN SEVAINE CREEK SYSTEMS Section VI gives the construction cost details for both flood control systems. Table VI-lin Section VI lists the unit prices used in the construction cost estimate. In general, a 10% construction cost contingency was used in the cost estimate for concrete channel construction. A 20% construc- tion contingency factor was used for the debris dams. A 15% contingency factor was used to cover engineering, inspection, and administration for the channel system. The engineering, inspection and administration costs for the debris dam were based on ASCE curves. The estimate for the geotechnical inves- tigation of the debris dam was based on a cost estimate by a geotechnical consulting engineering firm. xiii A. DAY CREEK CHANNEL SYSTEM Day Creek Debris Dam $ 2,375,000 Channel System 20,875,000 Day Creek Spreading Grounds 1,100,000 Day Creek Basin 2,500,000 Wineville Basin 2,650,000 Riverside Basin 5,850,000 Etiwanda Creek Channel 2,950,000 Subtotal $38,300,000 B. SAN SEVAINE CREEK SYSTEM • Etiwanda Debris Dam $ 1,950,000 Channel System 23,025,000 San Sevaine Basins 1 thru 4, 9,950,000 and Lower San Sevaine Basin Jurupa Basin 5,950,000 Subtotal $40,875,000 TOTAL SYSTEMS $79,175,000 The unit prices and estimates are based on November, 1982 prices when the ENR Index was 4533. To update the cost esti- mates, multiply by the ratio of the current ENR Index to 4533. The Day Creek Channel System includes Lower Etiwanda Channel below the San Bernardino Freeway. The San Sevaine Creek System includes the Upper Etiwanda Creek Channel above the Devore Freeway. Refer to Figure No. 1 of this report for a schematic alignment of the flood control systems. 6 xiv CONSTRUCTION SEQUENCE The recommended criteria and sequence of construction of the various reaches of the channel systems are outlined in detail in Section VII. The recommended priorities by system are listed below for ready reference. A. DAY CREEK SYSTEM 1. Development of Riverside and Wineville Basins, Lower Etiwanda Creek Channel, and the Day Creek Channel from Riverside Basin to the Devore Freeway Estimated Cost = $18,450,000 2. Day Creek Channel from the Devore Freeway to Highland Avenue, the Day Creek Debris Dam, and Day Creek Basin Estimated = Cost 8,075,000 I; 3. Day Creek Channel from Highland Avenue to the Debris Dam, and the development of the Day Creek Spreading Grounds Estimated Cost = 7,150,000 4. Day Creek Channel from Riverside Basin to Riverside Drive I; Estimated Cost = 6 4, 25,000 TOTAL COST DAY CREEK SYSTEM = $38,300,000 xv B. SAN SEVAINE CREEK SYSTEM 1. Development of the Lower San Sevaine Basin, San Sevaine Basins, Jurupa Basin, and approximately 2,600 feet of channel at Jurupa Basin to make basin function Estimated Cost = $17, 2. San Sevaine Creek Channel from just south of the Santa Fe Railroad to the Devore Freeway Estimated Cost = 6,550,000 3. Etiwanda Creek Debris Dam and Etiwanda Creek Channel from debris dam to the Devore Freeway Estimated Cost = 6,225,000 4. San Sevaine Creek Channel from the Riverside -San Bernardino County Line to the Santa Fe Railroad Estimated Cost = 9,625,000 5. San Sevaine Creek reception levee and channel from Summit Avenue to the LAW power line Estimated Cost = 1,350,000 TOTAL COST SAN SEVAINE CREEK SYSTEM = $40,875,000 Total Cost Day Creek and San Sevaine Creek Systems = $79,175,000 xvi It should u d be noted the construction sequences recommended in this report do not include proposed channel facilities in Riverside County. However, the Drainage Plan has to be viewed as an overall drainage plan for both counties because of the terminus of the channels at the Santa Ana River. Because of the necessary coordination with future channel construction in Riverside County, it may not be possible to construct the reach of channel below the Jurupa Basin until channel construction is accomplished in Riverside County. It is recommended that any construction be coordinated with the Riverside County Flood Control and Water Conservation District and that priorities be reviewed at least on a yearly basis with all involved agencies to re- establish priorities as necessary. xvii SECTION I INTRODUCTION AND SCOPE In November of 1981, Phase I of the Drainage Plan for the Day, Etiwanda and San Sevaine Creek System was completed. Phase I was an overview of the drainage and flood problems associated with the Day, Etiwanda and San Sevaine Creek watershed, and recommended methodology and the institutional framework for developing a Drainage Plan to resolve the drainage and flood problems. The Phase I Report reviewed alternate methods of improvement for the main channels, methods of financing construction of the systems, water conservation, and established a Technical Committee and Steering Committee to guide the development of the Drainage Plan. In February of 1982, Phase II of the Drainage Plan was initiated under an agreement involving the San Bernardino County Flood Control District and the Cities of Ontario, Rancho Cucamonga and Fontana. The Riverside County Flood Control District assisted in coordinating the development of the hydrology criteria and developed that portion of the Drainage Plan for San Sevaine Creek in Riverside County. The drainage plan for the Day Creek System ties to and was coordinated with the Riverside County Flood Control District's drainage plan for Day Creek at Riverside Drive, below the Pomona Freeway. Private developer interests in San Bernardino County also had a major role in the development of the Drainage Plan and participated in both the Technical and Steering Committees. The Day, Etiwanda and San Sevaine Creek Drainage Plan drainage area consists of approximately 82 square miles. The drainage boundary is generally Milliken Avenue on the west, Sierra Avenue on the east, the San Gabriel Mountains to the north, and the Jurupa Mountains and the County Line on the south. The drainage boundary and proposed 1 flood control system is shown on Figure No. 1 and the hydrology map is included in the packet of this report. The recommended flood control system consists generally of a concrete lined channel and debris dam for Day Creek, a concrete lined channel for Lower Etiwanda Creek below the San Bernardino Freeway, and water conservation basins and spreading areas. The San Sevaine Creek facility includes a concrete lined channel for Upper Etiwanda Creek and San Sevaine Creek below the Devore Freeway, and a large flood storage and water conservation basin for San Sevaine Creek above the Devore Freeway. An unlined reception levee and channel is proposed for San Sevaine Creek above Summit Avenue, although a lined channel and debris dam is included in the plan as an alternate. Because of possible cost savings, the lack of existing right -of -way, 6 and limited existing channel capacity downstream, there is no pro- posed channel for Etiwanda Creek between Foothill Boulevard and the San Bernardino Freeway. Upper Etiwanda Creek will confluence with San Sevaine Creek Channel at the Devore Freeway and become part of the San Sevaine Creek System. Lower Etiwanda Creek below the San Bernar- dino Freeway will outlet into Wineville Basin and become part of the Day Creek Channel System. Refer to Figure No. 1 for a schematic alignment of the proposed systems. • The Day, Etiwanda and San Sevaine Creek Drainage Plan was developed primarily for two reasons. Extensive development is proposed or under- way in the Cities of Rancho Cucamonga, Ontario and Fontana. Due to the lack of facilities in both Riverside and San Bernardino Counties, the development industry and the Cities were concerned with potential damage downstream due to increased runoff to be generated from pro- posed developments. Also, the County of Riverside, the recipient of all upstream runoff, had expressed concern for the potential in- creased runoff from the planned developments. Additionally, a large part of the developing area was subject to flood hazards due to the Po 2 lack of adequate flood control facilities. The lack of a coordinated Drainage Plan for the 82 square -mile area had also created undersized major channels to be constructed. There was also a need to develop additional water conservation facilities and to develop a water con- servation plan that could be coordinated with all of the affected agencies. Due to the above mentioned reasons and others, the various involved agencies and the development industry decided to initiate the development of a comprehensive regional Drainage Plan. Therefore, the Phase I Report was completed in November of 1981 and Phase II of the Drainage Plan was initiated in February, 1982. The various aspects of the comprehensive Drainage Plan are described in more detail below. The existing channel facilities for the various systems are described in this Section only in a general nature. Refer to Section V, Dis- cussion of Plan, and the Phase I Report for a more detailed descrip- tion of the existing facilities. In general, the Day Creek Channel exists as an inadequate earth - revetted channel for the most part from the Day Creek Spreading Grounds north of Highland Avenue to the San Bernardino- Riverside County Line. The Day Creek facility exists in Riverside County as an unimproved watercourse for the most part, with one short improved f reach of concrete lined channel below Bellegrave. Although the creek • flows through the Day Creek Spreading Grounds, Wineville Basin, and Riverside Basin, there are no adequate debris or storm flow storage facilities at the present time. P" San Sevaine Creek exists for the most part as an inadequate earth channel below the Santa Fe Railroad just north of the Kaiser Steel 4 Plant, to the Santa Ana River. There are several short reaches of concrete lined channel in Riverside County that are inadequately sized to handle the design flow. Above the Santa Fe Railroad, the San b 3 1 1 Sevaine Creek Creek System exists as a combination of natural drainage courses,a water - carrying street, revetted channels, and a series of basins. There are no adequate debris or storm flow storage facilities at the present time for the San Sevaine Creek System. Etiwanda Creek exists as a natural drainage course or revetted earth channel, except for a short reach of concrete lined channel under the Devore Freeway,and a lined reach of channel below the San Bernardino Freeway. There are no debris retention facilities for Etiwanda Creek. Due to the steep terrain and high debris loading, the existing reaches of earth - revetted channels are not adequate to sustain major flood flows. Therefore, major parts of the drainage area of the Day, Eti- wanda and San Sevaine Creek System are subject to flood hazards. i This report includes the preliminary plan and profiles for the flood P P Y P P ,channel systems. Volume I of the report includes the hydrologic and hydraulic design criteria, debris dam and basin design criteria, construction cost estimates, and the recommended priority and channel system construction sequence. Each reach of each channel system is discussed in Section V. The 11ex 17" plan and profile sheets for r the channel, debris dams, and flood storage and water conservation basins are included in Volume II of this report. The plan and profile om sheets of the various reaches of the channel systems should be used only as a guide. The Design Engineer should provide hydraulic calcu- lations for each system based on latest design information. Sections II and III discuss the hydrologic and hydraulic design criteria in detail, and Section IV discusses the debris dam and basin design criteria. Planning for the flood control systems presented herein is predicated on accepted hydraulic principles. However, final design will have to be based upon actual field conditions as deter- mined by field surveys and detailed engineering. Elevations and 4 distances have been taken from the best available topographic and existing plans of the area, and are sufficient for alignment and grade and cost estimates for preliminary purposes. Each reach of channel system must be designed and new cost estimates prepared for construction. Every effort was made to locate and avoid major interferences with larger utility lines as indicated on the plan and profile drawings, but field checks and surveys must be made to locate these lines more precisely, and to establish the final location of flood control facilities as necessary for economy of construction. Unit prices used in preparing cost estimates were based on the best information available at the time and referenced to the November, 1982 Engineering News Record Index of 4533. To update the cost estimates, multiply by the ratio of the current ENR Index to 4533. The construction cost estimate for the Drainage Plan is covered in Section VI. Various elements of the overall Drainage Plan not covered in this report are covered in various supplemental reports. Water conser- vation is covered in Section V, and the proposed plans for developing the spreading grounds and water conservation basins are included with the plans in Volume II of this report. However, a more detailed analysis of water conservation is covered under the supplemental report entitled "Day, Etiwanda and San Sevaine Creek Drainage Plan, Water Conservation Report ", dated March, 1983. A separate report on "Funding Mechanisms for the Day, Etiwanda and San Sevaine Creek Drainage Plan ", dated March, 1983, covers a preliminary financial analysis for construction of the Drainage Plan. Although the finan- cial analysis is preliminary in nature and will not preclude the need for an in -depth financial analysis and plan, it does provide a summary k and decisions to date, and provides the basic framework for a final financial plan. r 5 c SECTION II HYDROLOGIC DESIGN CRITERIA 1. INTRODUCTION The methodology and peak runoff flows for the Drainage Plan were developed by Williamson & Schmid in conjunction with Bill Mann & Associates, the San Bernardino County Flood Control District, and Riverside County Flood Control District. The hydrology report entitled "A Hydrologic Analysis of the Day Creek /San Sevaine Watersheds in the County of San Bernardino" dated June, 1982, is included in the Appendix in its entirety. The results of that study and other criteria developed are summarized herein for ready reference. At the time the Day, Etiwanda and San Sevaine Creek Drainage Plan was initiated, San Bernardino County did not have a methodology adequate for the analysis of the subject watershed ' hydrology. Because of this,and due to the fact both the Day Creek and San Sevaine Creek Watersheds cross jurisdictional boundaries into Riverside County, the Riverside County Flood Control and Water Conservation District unit - hydrograph method P„ was used for a previous study on the Day Creek System only. Following the initial study, the Day Creek Watershed was re- defined, and San Sevaine Creek was added to the Drainage Plan. it Another hydrology study was prepared entitled "Progress Report on Day Creek /San Sevaine Channel Hydrology Study" dated April, 1982. That report is not included herein, but is on file with lilt the San Bernardino County Flood Control District. • it Recently, the San Bernardino County Flood Control District com- l.. pleted an in -depth analysis of unit - hydrograph methodologies and 6 1 1 developed a new County procedure for use in hydrology studies. A San Bernardino County Hydrology Manual is presently being prepared by Williamson & Schmid.. See Reference 4 in Appendix. Due to the advent of the San Bernardino County Flood Control District unit - hydrograph procedure, a comparative study was initiated wherein the San Bernardino County Flood Control District and Riverside County Flood Control District unit - 1 hydrograph results were compared for the Day Creek and San Sevaine Creek Watersheds. The San Bernardino County Flood 1 Control District methodology and peak flows were determined to be appropriate to use for this Drainage Plan and the hydrology 1 report referred to above entitled "A Hydrologic Analysis of the Day Creek /San Sevaine Watersheds in the County of San Bernardino" was adopted. As indicated, that report is included in the Appendix. • 1 A watershed boundary map showing the areas tributary to the Day Creek Channel System and the San Sevaine Channel System 1 is included in this report. The watershed boundary map also shows the node points for developing channel reaches of incre- 1 mental design flows. The watershed boundary .map included in the packet of this report shows an area west of the Day Creek tributary to the Day Creek Basin labeled "Area Deleted Due to Retardation ". This area will be drained totally to the Day Creek Basin by a future storm drain system. Because Day Creek 1 Basin can store a 100 -year storm flow, this tributary drainage area has been deleted from the Day Creek Channel watershed area. 1 Figure No. 1 of this report shows schematically the watershed boundary and various system alignments. 1 1 1 7 1 2. GENERAL ANALYSIS OF AREA AND METHODOLOGY The study area comprises approximately 82 square miles, mostly of valley land between the San Gabriel Mountains on the north and the Jurupa Hills to the south, and between Milliken Avenue on the west, and Sierra Avenue on the east (see Figure No. 1 and the drainage map included in the packet of this report). The major part of the terrain is primarily an alluvial fan which can be expected to have the hydrologic characteristics of a valley area. Typical of such geologic formations, most of the surface soils in the upper part of the fan are relatively coarse and absorbent, whereas surface soils in the lower reaches of the fan and in established streambeds consist of finer materials of less permeability. Isohyets for a 24- hour,100 -year storm (NOAA ATLAS 2) indicate rainfall in the study area ranging from about 14 to 20 inches in the foothills down to 6 to 7 inches near the Riverside County Boundary. The significance of this differential, which appears to be repeated generally in isohyets for longer dura- tion records is the apparent variation of rainfall intensity over the area for any rainfall event. This variation must be taken into account in storm drain planning for the area and in sizing the major trunk lines for the systems. The 24 -hour isohyetals are shown on Figure No. 3. Generally, when analyzing watersheds for flood flow character- istics, it is desirable to collect data on stream discharge, along with data on precipitation, soil types, etc. Because of the lack of stream gages on some streams and the destruction of other gages during the 1969 flood, stream discharge data is not adequate for the study area. Precipitation and stream flow data are available from the U. S. Weather Service, U. S. 8 ` � `• `♦ / \ • s. 22" - -- ��� i 1 \ ■ 20 '' -- - - -. --. .- .- - - - A 1 ) 1 . 18 "EEE --' / 16 " 12" ^~ -- - . -. r . --I / - / r . . — .. ' SCALE • —r -- — _ - - ■ �.,: 9000' r 8 „ r- . t__ '` 1 7 ,,,r ) i / 1 �♦ • FIGURE 3. NOAA ATLAS 2, 24 -HOUR ISOHYETALS 9 Geological Survey, California Department of Water Resources, and the Counties of San Bernardino and Riverside for selected stations in the valley area. However, sufficient data is not normally available for treatment of specific watersheds. Be- cause of this reason and others, synthetic flood hydrology methods are required. Two basic flood hydrology methods are normally adapted to specific watersheds to determine design discharges. The rational method or modified rational method is normally used for small watersheds of less than 500 acres. Some form of the unit - hydrograph method is used for larger watersheds and where storm volume totalsare desired. The unit - hydrograph method was used for this Drainage Study. The detailed hydrology methodology, hydrology watershed para- meters used, and the evaluation of the model results are in- cluded in the hydrology report in the Appendix and are not repeated here. The return period or design storm frequency is normally the 100 -year event for major channels. The 100 -year design frequency was used in this study. The side drain laterals connecting to the channel systems, existing or proposed, have been considered and are shown on the plans. The laterals are based on the comprehensive storm drain plans for the various jurisdictions and the specific storm drain plan should be reviewed. The side drainage laterals are generally based on a 25 -year design storm; however, each comprehensive storm drain plan should be reviewed for specific details. 10 3. UNIT - HYDROGRAPH PEAK FLOW RATES For read y reference, the peak flow rate estimates at certain & selected points are tabulated below. The design flow is based on a 100 -year frequency, 24 -hour storm. Table No. 1 DAY CREEK SYSTEM Watershed Location Design Flow Point General 24 -hour Storm Number * Description Q100 (cfs) ** 1 Day Creek Canyon Mouth 5,310 2 Highland Avenue 6,214 rat 3 Devore Freeway 7,375 4 San Bernardino Freeway 8,156 op 6 Wineville Basin 9,260 ir 8 Riverside Basin 9,718 11 m y w Table No. 2 SAN SEVAINE SYSTEM (Basin Storage Not Considered) Watershed Location Design Flow Point General 24 -hour Storm I; Number * Description 4100 (cfs) ** 1 San Sevaine Canyon Mouth 1,967 PP 2 Etiwanda Canyon Mouth 3,077 3 Etiwanda Creek @ 24th Street 5,287 4 San Sevaine Creek @ Devore Flay 7,115 4' Etiwanda & San Sevaine Creek 11,971 PR Channel @ Devore Freeway �Yr 5 Combined San Sevaine Creek 16,201 Channel @ Devore Freeway 7 San Sevaine Creek Channel @ 20,500 Baseline 8 San Sevaine Creek Channel @ 20,500 Foothill 9 San Sevaine Channel @ West 20,500 �. Fontana Channel 11 San Sevaine Creek Channel @ 23,150 the San Bernardino Freeway 12 San Sevaine Creek Channel @ 23,150 L . the Pomona Freeway 1 1 12 Table No. 3 II SAN SEVAINE SYSTEM (Basin Storage Considered) I" ii Watershed Location Design Flow Point General 24 -hour Storm Number * Description Q100 (cfs) * ** r i 1 San Sevaine Canyon Mouth 1,967 2 Etiwanda Canyon Mouth 3,077 Pm 3 Etiwanda Creek @ 24th Street 5,287 ii 4 Lower San Sevaine Spillway 4,100 4' Combined Etiwanda & San Sevaine 6,300 II Creeks immediately north of Devore Freeway 5 Combined San Sevaine & Etiwanda 8,200 Creeks immediately south of Devore Freeway 7 San Sevaine Creek Channel @ 12,200 i ii Baseline Avenue 8 San Sevaine Creek Channel @ 12,200 r. F oothill Boulevard h. 9 San Sevaine Creek Channel @ 15,550 m West Fontana Channel ig 11 San Sevaine Creek Channel @ 18,850 San Bernardino Freeway OR 11' San Sevaine Creek Channel @ 12,100 ii Jurupa Basin 12 San Sevaine Creek Channel @ 15,100 1 Pomona Freeway ii OR II re iii 13 y An NOTES * The "watershed location point number" refers to the node numbers on the respective Day Creek and San Sevaine Creek Systems. ** The peak design flow values do not take into considera- tion the storage capabilities of the upstream water conservation basins. * ** The peak design flow values take into consideration I; flood storage capabilities of Lower San Sevaine Basin and Jurupa Basin. The Drainage Plan and hydrology map show the watershed points of concentration used in the hydrology analysis. The node points ib are listed in Table Nos. 1 thru 3 with the design flows at the node points. The node points are also referenced in the de- o tailed hydrologic analysis included in the Appendix of this report. The hydrology map is included in the packet of this Pft report. Review of the hydrology map and Figure No. 1 indicates there are several spreading grounds and retention basins existing on line with the major watercourses. Although the potential areas are extensive, the spreading grounds and basins are basically • undeveloped, with a few exceptions. Except for Lower San Sevaine and Jurupa Basins on the San Sevaine Creek System, neither the existing nor future basins were con- sidered for flood storage in the hydrology studies. Lower San Sevaine Basin was designed to provide 1,720 acre -feet of flood storage on a flow - through basis, and Jurupa Basin was designed to provide a flood storage capacity of 1,300 acre -feet. The preliminary plans for Jurupa Basin were developed as a bypass e• system. The Jurupa Basin plans will need a detailed computer 14 0 6 modeling analysis in the final design stage. It is proposed to remove 6,750 cfs from the peak design flow of 18,850 cfs with an overside spillway outletting into Jurupa Basin. San Sevaine Basin, even though designed as a flow- through basin, will decrease the San Sevaine Creek flow above the Devore Freeway from 7,115 cfs to 4,100 cfs. The basin will be designed to drain within 24 hours by adding an additional drain. The existing basin and proposed basin expansion are shown on the preliminary plans included in Volume II of this report. Because of the desire the Riverside County Flood Control and e by e e Cou ty o Water Conservation District to consider upstream flood storage capability in Lower San Sevaine and Jurupa Basins, that District assisted in revising the hydrologic analysis for the San Sevaine Channel System. The Riverside County Flood Control and Water ow Conservation District revised the design flows using their 6 computer program. Table No. 3 shows the revised design flows for the San Sevaine System using flood storage in Lower San Sevaine and Jurupa Basins. Table No. 2 shows the design flows with no route -down of flows due to basin storage. By considering the flood flow storage affects in Lower San Sevaine and Jurupa Mi Basins, a considerable savings in construction costs can be Po realized in downstream channel construction due to possible downsizing. aim Except for 730 acres that are tributary to Day Creek Basin, no flood storage or route -down of design flows were considered for the Day Creek Channel System. The 730 acres tributary to Day Creek Basin will drain to the basin by storm drains under ultimate development conditions. Due to the fact the future basin expansion will store a 100 -year frequency storm flow from o. the 730 acres, the area was removed from the drainage area it 15 tributary to Day Creek Channel. The Day Creek Basin and its tributary area is shown on the hydrology map and Figure No. 1. Although Wineville and Riverside Basins were designed to pro- vide for substantial water conservation storage, 700 acre -feet and 1,100 acre -feet respectively, the channel design flow below these basins was not decreased because of this storage capa- bility. The decision not to route -down channel flows was based on discussions with both Flood Control Districts. The unknown time frame of directing upper Etiwanda Creek flows to the San Sevaine Creek Channel and the existence of a short reach of downstream channel in Riverside were instrumental in the decision. However, Wineville and Riverside Basins were designed as water conservation basins and will provide substantial flood flow storage and regulation prior to completion of the ultimate channel south of the basins. The basins will also provide retention of increased drainage flows due to development as the upstream area develops. 4. WATER CONSERVATION AND FLOOD STORAGE BASINS The Drainage Plan includes a number of spreading grounds and basins that will be expanded or newly developed for water con- servation purposes. A separate report entitled "Day, Etiwanda and San Sevaine Creek Drainage Plan, Water Conservation Report" goes into the water conservation aspects in more detail. How- ever, the basin storage capacities are listed below for ready reference. The existing and proposed water conservation facilities are shown on Figure No. 1 and on the Drainage Plan and hydrology map included in the packet of this report. Refer to the Water Conservation Report on file with the San Bernardino County Flood Control District for details on the water conser- vation plan. 16 The available storage volume in the proposed basins is given in Table No. 4. Due to the significant storage capacity in the basins, the water conservation aspects of the plan can be significant once the basins are developed to their ulitimate capacity. As indicated above, the Lower San Sevaine and Jurupa Basins were considered as flood storage basins. Additionally, Day Creek Basin provides for 100 -year frequency storm storage for 730 acres on the Day Creek Channel System. These basins will also act as water conservation facilities and are included in the tabulation below. Table No. 4 WATER CONSERVATION BASINS STORAGE VALUES Storage Volume System Basins (acre -feet) Day Creek Day Creek Spreading Grounds " Day Creek Basin 650 to Wineville Basin 700 Riverside Basin 1,100 San Sevaine San Sevaine Spreading Grounds Etiwanda Spreading Grounds " Etiwanda Basins 60 San Sevaine Basins 1,2,3,4 440 Lower San Sevaine Basin 1,720 " Victoria Basins 240 Jurupa Basins 1,300 * The San Sevaine Spreading Grounds and Etiwanda Spreading Grounds are flow through systems and no estimate was made on possible storage volume, if any. 17 SECTION III HYDRAULIC DESIGN CRITERIA 1. GENERAL DISCUSSION The hydraulic criteria presented herein have been used in the comprehensive plan design to the extent called for in the limited amount of detailing required for preliminary channel design and cost estimating purposes. Some of the recommended criteria were not used because of scope limitations, but they are given here as a guide and they should be used in final design. The primary purpose for such detail in the final channel plan design is to predict and minimize wave action and other disturbance patterns that might cause overtopping of channel walls and surging. The basic procedure that is recommended, regardless of the conduit used, is to plot both energy and hydraulic grade lines on all profiles and to show values of all hydraulic elements for each uniform reach (Dn, Dc, Q, n, Sf, F, etc.). At all confluences, transitions, and necessary sharp changes in grades, it is necessary to use energy head and momentum methods to avoid unworkable design. Sharp breaks in slope should be avoided if possible. Where sharp changes in grade are neces- sary, such as debris dam spillway designs, vertical curves should be used. In open channels, undesirable wave action and other disturbances are most troublesome at near - critical flow where the Froude number is close to unity. Unfortunately, because of the natural ground slopes in the study area, the design flow rates, and most efficient sections for open channels, the Froude number 18 is often in this range. Accordingly, the criteria apply principally to changes in channel section, slope and direc- tion of flow. In general, hydraulic methods and design criteria based on the Los Angeles County Flood Control District experiences and practices are recommended herein. Los Angeles County Flood Control District criteria were used because of its experience in the San Gabriel Mountain frontal area. The latest Los Angeles County Flood Control District Hydraulic Design Manual should be used as a reference. The San Bernardino County Flood Control District will be the governing agency on design, and a review with the District should be held prior to initia- ting design to obtain any specific design criteria and to discuss specific concerns. The following general criteria for conduit design should be used: A. All channels should be concrete lined. No ABM will be allowed. B. Manning's n = 0.015 C. Side slopes for trapezoidal channels = 12:1 D. Provide streamlined extension of dividing walls upstream and downstream of culverts and bridges for thickness ex- ceeding one foot (1'). E. Pipe inlet structures should confluence with channel at 45 degrees for sizes 36 inches to 57 inches, and 30 degrees for sizes 60 inches to 72 inches. Use special junction structure for pipes 78 inches and larger. 19 F. Due to the high channel flows and relatively steep terrain in some locations, the velocities are very high, particu- larly in the upper channel reaches. The channel velocities vary from 50h fps to 68± fps above Highland Avenue, and 30 fps to 46± fps for the reach from Riverside Basin to Highland Avenue. ■ During the final stages, the high channel velocities should be recognized and adequate design features should be in- corporated in the plans to minimize the affects of scour where possible. This will probably be in the form of thickened inverts, although other methods should be reviewed. FPI The following invert thicknesses were used in the cost �• estimates for the following reaches: .. 1) Day Creek Channel above Highland Avenue and the Upper Etiwanda Creek Channel - 12" (rectangular channel) 2) Above Foothill Boulevard - 9" (trapezoidal channel) 3) Below Foothill Boulevard - 8" (trapezoidal channel) The listed invert thicknesses were used to achieve a realis- tic cost estimate, and the actual thickness should be deter- ,, mined in the final design stage. 1 G. Most channel crossing structures are shown on the plans as reinforced concrete boxes with transitions connecting the structures to the channels. Consideration should be given "" to the use of clear span structures with channels without transitions in the final design stage. Economics should govern the design. Generalized typical sections showing this alternative are shown on the plan. 6 20 [61 2. HYDRAULIC CRITERIA A. General a It is not the intent of this Section to set detail design g criteria or methods of design. To some degree, the methods of design should be at the discretion of the engineer. However, to provide guidance and prevent the submittal of unacceptable design calculations, recommendations for methods and design criteria are provided herein. If the engineer chooses to submit designs using alternate methods and criteria, he should first check with the Flood Control MP District. 1 In general, all open channels should be designed with the tops of the walls or levees at or below the adjacent ground om to allow interception of surface flows. If it is unavoid- r able to construct the channel without creating a pocket, a means of draining the pocket must be indicated on the drawings. In making preliminary layouts for the routing of proposed channels, it is desirable to avoid sharp curvatures, re- versed curvatures, and closely spaced series of curves. If this is unavoidable, the design considerations in Section III,2 -D shall be followed to reduce superelevations and to eliminate or reduce initial and compounded wave disturbances. 1 It is generally desirable to design a channel for a Froude number of just under 2.0. In the study area, however, this 11 is not always possible because of steep terrain. If the Froude number exceeds 2.0, any small disturbance to the 1 21 iii C p water surface is amplified in the course of time and the flow tends to proceed as a series of "roll waves ". Reference is made to Section III,2 -F for review and design criteria that can be used when designing a channel with a Froude number exceeding 2.0. 1 In the design of a channel, if the depth is found to be P" at or near critical depth (Froude number = 1.0) for any significant length of reach, the shape or slope of the 01 channel should be altered to secure a stable flow condition if possible. Water surface profile calculations should be calculated using the Bernoulli energy equation combined with the owl momentum equation for analyzing confluences and junctions. Friction losses should be calculated by an accepted form of the Manning equation. Calculations to be submitted for review should proceed upstream when the depth of flow is PP greater than critical depth and downstream when the depth of flow is less than critical depth. Junction losses shall I „ be evaluated by the pressure plus momentum equation. Refer to References 5 and 7. B. Transitions Transitions normally occur at changes in channel section or at crossing structures. Such transitions take several forms depending upon the design velocity, available dis- tance within which to make the transition, etc. Transi- • tions which involve hydraulic jumps and highly super- critical flow situations require special consideration. The information given below is based on the Los Angeles Poo County Flood Control District Hydraulic Design Manual and 22 is provided herein as a guide. The engineer shall provide design calculations and a water surface profile with the design plans. Refer to Reference 5 for criteria. 1) Subcritical Flow Plo For subcritical velocities less than 12 fps, the angle of convergence of divergence between the centerline of the channel and the wall shall not exceed 12 ° 30'. The length of the transition (L) shall be determined from oi* the following equation: 2.5 ,.. where G1 B = The difference in channel width at the le water surface between the upstream and w. downstream ends of the transition. For subcritical velocities equal to or greater than 12 fps, the angle of convergence or divergence between the centerline of the channel and the wall shall not '" exceed 5 ° 45'. The length (L) shall be determined from the following equation: L = 5.04113 Head losses for transitions with converging walls can be determined by methods shown in Section(F)of the Los urn Angeles County Flood Control District Design Manual or any other approved method. P 23 MI 2) Supercritical Flow ii a) Divergent Walls The angle of divergence between the centerline of the channel and the wall shall not exceed 5 ° 45 ` or tan F /3, whichever is smaller. The length of the transition (L) is the longest length determined r i II from the following equations: 1 li L. 15.O Q8 L. = /.5 A a •F ii where F = Upstream Froude number based on depth +pi+ of flow. it r d B = The difference in channel width at the water surface. 1. " LBO b) Convergent Walls r Converging walls should be avoided when designing "' channels in supercritical flow; however, if this is impractical, the converging transition shall be ill designed to minimize wave action. The walls of - the transition shall be straight lines. • e iii Bs _ � - e �''" t , iti "' '4111111.11.11111 1 ji . i AIo,, Wei ' - '•1 iiT Or r -' 102 . ID3 , 4 /rte rzr----- gehcmotic profile ",, - /--- i ii. 8i" Bg 24 L- 2 ft:VI Refer to the Los Angeles County Flood Control sow District Hydraulic Design Manual for more specific details and applications. C. Piers 0014 The effect of piers on open channel design shall be con - sidered at bridge crossings and where an open channel or box conduit not flowing full discharges into a length of IN multi - barreled box. This effect is especially important when flow is supercritical and when transported debris oft impinges on the piers. ""'' The total pier width shall include an added width for design purposes to account for debris. Streamline piers �.. should be used when heavy debris flow is anticipated. The water surface elevations at the upstream end of the pft n piers shall be determined by equating pressure plus momentum. The water surface profile within the pier reach shall be determined by the Bernoulli equation. The water surface rr elevations at the downstream end of the piers may be deter- r mined by applying either the pressure plus momentum equation or the Bernoulli equation. Refer to the Los Angeles County Flood Control District Hydraulic Design Manual or other appropriate design manuals for specific details on the use of the P + M Equation. P P 25 D. Curving Alignments 1) Superelevation Superelevation is the maximum rise in water surface at the outer wall above the mean depth of flow in an equivalent straight reach, caused by centrifugal force in a curving alignment. a) Rectangular Channels For subcritical velocity, or for supercritical velocity where a stable transverse slope has been attained by an upstream easement curve, the super - elevation (S) can be calculated from the following equation: S = V2b 2gr For supercritical velocity in the absence of an upstream easement curve, the superelevation (S) is given by the following equation: S = V2b gr Where V = Velocity of the flow cross - section, in fps b = Width of the channel, in ft. g = Acceleration due to gravity r = Radius of channel centerline curve, in ft. X = Distance from the start of the circular curve to the point of the first (S), in ft. D = Depth of flow for an equivalent straight reach 1 3= Wave front angle 26 r b r-- ./6 6 l/ 0.908 6 - V/290 m \ ID S in 4 fr b) Trapezoidal Channels For subcritical velocity, the superelevation (S) can be calculated from the following equation, and includes 15% factor of safety: v (b - /l5 "- z. 2.D) 2gr Where z = Cotangent of bank slope b = Channel bottom width, in ft. For supercritical velocity, curving alignments shall have easement curves with a superelevation (S) given by the following equation: 5 = 43 V2 (b t 2Z. r�) 9r A 30% factor of safety is included. 27 2) Easement Curves Easement curves are alignment transition curves, employed upstream and downstream of circular curves, when supercritical flow exists in open channels. The purpose of the easements is to alter the transverse slope of the water surface and keep the water prism in constant static equilibrium against centrifugal force throughout the entire length of the easements and central circular curves, thus achieving minimum heights of superelevation with avoidance of cross -wave distur- bances. Circular easement curves are recommended in lieu of spiral transition curves for ease of design and con- struction. Also, very little hydraulic advantage is gained by the use of the spiral. The circular easement curve consists of curved sections upstream and downstream of the main curve having a radius (2R), twice the main curve radius (R). a) Conditions Requiring Easement Curves - When the freeboard, above superelevated water surface (as calculated without an easement curve) is less than one foot (1'). - In reverse curves or on alignments where curves follow one another closely. - For any case where elimination of cross -wave disturbances is required. (If easement curves are not used, additional freeboard downstream of the curve may be necessary.) 28 - In trapezoidal channels for all cases of super- critical velocity. b) Length of Easement Curve � b L ton A3 . / \tip For rectangular channels, the length of easement curve (L is given by the following equation: Lis = 2x For trapezoidal and associated channel types, the length of easement curve (L can be calculated as follows: L fi a .52(b Zz VV 4 -5-- Refer to D,1 -a for the definition of terms. 29 E. Freeboard Freeboard is the additional wall height applied to a cal- culated water surface. For average flow velocities of 35 fps or less, add two feet (2'). For curved alignments, add two feet (2') or one foot (1') above the superelevated water surface, whichever is greater. For average flow velocities greater than 35 fps, add three feet (3'). For curved alignments, add three feet (3') or two feet (2') above the superelevated water surface, which- ever is greater. It may be necessary to increase the channel freeboard in the event of excessive "roll waves" in the channel due to steep slopes. Roll waves are discussed in Section III,2 -F. Refer to References 1 and 3 for applicable design criteria. F. Roll Waves Roll waves, sometimes known as slug flow, are intermittent surges on steep slopes that will occur when the Froude number (F) is greater than 2.0 and the channel invert slope (So) is greater than the quotient,(12)divided by the Reynolds number (R). When they occur, it is important to know the maximum wave height at all points along the channel so that appropriate wall heights may be determined. Based on experimental results of roll waves by Richard R. Brock, the maximum wave height can be estimated. A copy of the report by Brock is on file with the San Bernardino County Flood Control District. Other information and sample problems are available in the Los Angeles County Flood Control District Hydraulic Design Manual. 30 The freeboard allowances recommended in Section III, 2 -E above is based on Los Angeles County Flood Control District criteria. "Roll Waves" and freeboard allowances are also discussed in the U. S. Corps of Engineers' "Hydraulic Design of Flood Control Channels" manual (Reference 3). The Corps of Engineers' freeboard criteria is generally lower than the Los Angeles County Flood Control District's; however, they refer to the necessity for modeling and /or special computations under certain conditions. 31 SECTION IV DESIGN OF DEBRIS DAMS AND BASINS 1. BASIN DESIGN A. General Consideration of debris loads carried by streams below mountain and foothill areas is essential in planning and design of flood control facilities. Failure to pro- vide either debris storage dams or additional hydraulic capacity for debris bulked flows can seriously affect the performance of flood control structures. Criteria for debris basin design is usually based on pro- viding storage capacity for debris generated by a single major flood event as a minimum. Considerable information has been gathered by the Los Angeles County Flood Control District on their large network of dams and debris basins. Maximum single storm debris production rates as high as 120,000 cubic yards from a one - square mile watershed, and single season rates as high as 150% of the maximum single storm rate, have been recorded. Debris volumes carried by flowing streams which equal the clear water volume of the stream (100% bulking) have also been recorded. In the following paragraphs, references and methods are discussed for estimating storm debris production rates. It should be emphasized the information provided herein is for guidance only to make the Engineer aware of some of the information available and some of the methods that have been used in evaluating debris related problems in the 32 Southern California area. This information should be supplemented by other information provided by the Engineer. The design should be based on the latest information available and the latest available engineering practice. Burn history is an important factor in debris studies. Debris discharges from totally burned watersheds may be many times the rate of an unburned watershed. Valuable information on historical fires can often be obtained from the U. S. Forest Service or California Division of Forestry for use in making debris studies. Because of the experience the Los Angeles County Flood Control District has had with debris movement in the San Gabriel Mountains, its criteria was used in the preliminary design of the debris dams as shown on the plans. Debris dams are recommended for Day and Etiwanda Canyons. An alternate design is shown for San Sevaine Creek with a concrete channel and debris dam. A debris volume of 100,000 yd per square mile of drainage area was used in the preliminary design of the dams. Because of the above mentioned experience of the Los Angeles County Flood Control District in the San Gabriel Mountain frontal area, its "Debris Dams and Basins" Design Manual is recommended as a guide and for basic design criteria. The Los Angeles County Flood Control District manual should be supplemented by information and criteria by the San Bernardino County Flood Control District and State regula- tions on dams. In cases where recent watershed burns have occurred, debris volumes and spillway design may need to be modified to account for potential increased debris movement. Additionally, because of the experience of the U. S. Corps of Engineers in designing and constructing debris dams in 33 the San Gabriel Mountain Watershed, their manual entitled "A New Method of Estimating Debris - Storage Requirements for Debris Basins" is recommended. The sizing of the basin to contain the volume of debris to be impounded by the dam is accomplished by trial and error. The designer should be aware that certain dams as defined in the "Statutes and Regulations Pertaining to Supervision of Dams and Reservoirs" published by the State Department of Water Resources, Division of Safety of Dams, will fall under State jurisdiction. The designer should review regulation and design criteria established by the State. B. Debris Volume and Basin Capacity Unless other criteria is established by the San Bernardino County Flood Control District, the required debris capacity for design of the basin shall be determined from the Debris Production Curves in the Los Angeles County Flood Control District manual. The San Bernardino County Flood Control District should be contacted prior to initiation of design. Because it is possible to have drainage area conditions which may affect the use of the curves, confirmation as to application of the curves should be obtained from the District. The calculations for the debris volume shall be based on the assumption that the debris will be deposited in such a manner that the debris slope, sloping upstream from the spillway crest, will be equal to 60% of the average slope of the original streambed for the total length of the basin site. 34 2. DEBRIS DAM DESIGN The height of the dam is measured vertically from the spillway crest to the natural bed of the stream or watercourse at the downstream toe of the dam. Due to the close proximity of the Cucamonga Fault to the pro- posed dam sites, a detailed geotechnical and soil investigation analysis and report will be necessary prior to design of the debris dam. A "Reconnaissance Geotechnical Investigation" has been prepared for the Day Creek and Etiwanda Creek debris dam sites. This preliminary report will provide some preliminary information on design criteria and is on file in the Flood Control District office. The crest of the dam shall be 20 feet wide unless otherwise determined by the Flood Control District. The need for pro- tection of the faces of the dam shall be determined by the Design Engineer with recommendations on the plan accordingly. Access to the dam and basin shall be provided. Access road width and maximum grades shall be determined by the District. 3. SPILLWAY DESIGN The Flood Control District will provide assistance in the determination and /or confirmation of the design flow. It is recouuuended that confirmation of design flows be reviewed and confirmed with the District prior to start of design. It is assumed all debris dam spillways will be rectangular. The width and height of spillways at the crest shall be determined 35 by use of the broad crested weir formula. The coefficient of discharge (c) shall be 2.80 unless otherwise determined by the District. The spillway shall be sized to pass the design flow with an allowance made for potential increased flow due to watershed burns and adequate freeboard. Reference is made to the Los Angeles County Flood Control District manual for guidance. Specific spillway design criteria shall be reviewed with the San Bernardino County Flood Control District. The minimum freeboard at spillway crest shall be two feet (2') or equal to 25% of the head differential from the spillway crest to water surface in the basin, whichever is greater. Downstream of the crest, the minimum freeboard shall be two feet (2') for average velocities of 35 fps or less, and three feet (3') for average flow velocities greater than 35 fps. Consideration shall be given in each individual project to the conditions of soils, groundwater level, existence of adjacent fault zones, slope of adjacent ground surface, and existing and proposed live loads. Analysis of the spillway structure shall be made on empty and flowing full conditions. 4. OUTLET WORKS An outlet drain shall be provided to drain the basin and /or direct flood flows to the spreading ground areas. The outlet drain shall be reinforced concrete pipe, encased in concrete, with a minimum diameter of 36 inches. Cutoff collars shall be 36 provided to prevent piping along the pipe encasement. The slope of the drain should be 5% or greater, unless otherwise approved. An outlet tower shall be provided. The tower shall be located at the lowest point of the basin and constructed to a height that shall project at least one foot (1') above the theoretical debris slope line. Reference is made to the Los Angeles County Flood Control District Design Manual, Debris Dams and Basins, for general guidelines. Detail basin of the outlet works shall be based on preliminary plans submitted to the San Bernardino County Flood Control District for review and approval. 5. REFERENCES AND ADDITIONAL DEBRIS ANALYSIS It is recommended an analysis and recommendation on debris potential and design be made to the Flood Control District prior to determination of final design methodology and criteria and prior to initiation of the final design of the debris dams and reservoirs. A detailed geotechnical and soils investigation analysis and report will be necessary for final design. The debris dams will come under the jurisdiction of the State Division of Safety of Dams criteria and will have to be designed accordingly. Debris production rates and analysis by the Los Angeles County Flood Control District and the U. S. Corps of Engineers are referenced in the Appendix. 37 SECTION V DISCUSSION OF PLAN 1. GENERAL Under the storm drain plan for Day, Etiwanda and San Sevaine Creeks presented herein, the approximate 82 square mile study area will be drained by two major channel systems. These two major systems are the Day Creek System and the San Sevaine Creek System. The drainage plan and hydrology map included in this report showsthe overall drainage boundary, the sub - system drainage areas, the design flows, and the major channel systems. The Upper Etiwanda Creek drainage area flows will ultimately be directed to the San Sevaine Creek System at the Devore Freeway. A debris dam below the mouth of Etiwanda Canyon and a concrete lined channel from the canyon mouth to the existing channel under the Devore Freeway is proposed. The channel will follow the existing Etiwanda creek flowpath. A concrete lined channel from the existing channel under the Devore Freeway to the Santa Ana River will provide for the combined Upper Etiwanda Creek, San Sevaine Creek, and all tributary flows to San Sevaine Creek. This system is shown on the Drainage Plan map and will be dis- cussed in more detail below. The Lower Etiwanda Creek flows will be directed to the Day Creek System. A concrete lined channel for Lower Etiwanda Creek flow is proposed from the San Bernardino Freeway to Wineville Basin, a part of the Day Creek System. The Day Creek System extends from the Day Creek canyon mouth to Wineville and Riverside Basins and ultimately to the Santa Ana River. 38 The Lower Etiwanda Creek drainage is considered part of the Day Creek System. The Day Creek System is shown on the Drain- age Plan map and will be discussed in more detail below. The proposed channel systems are designed for a 100 -year frequency storm. The channels are designed with a two foot (2') freeboard for channel flow velocities less than 35 feet per second and three feet (3') of freeboard where the channel flow velocity is greater than 35 feet per second. The debris dams proposed for Day Canyon and Etiwanda Canyon are designed to store a maximum single storm debris loading with a debris production of 100,000 cubic yards per square mile of drainage area. The Drainage Plan recognizes the existing comprehensive storm drain plans and existing storm drain facilities that will con- duct drainage flows to the proposed channels. The preliminary channel plans provided in this report are designed to receive these flows. The existing comprehensive storm drain plans, existing drainage facilities, and other proposed drainage plans are listed below for reference. The storm drain plans and existing facilities will be discussed in more detail below under the various channel systems. The comprehensive storm drain plans and existing major storm drains are listed below. A. San Bernardino County Comprehensive Storm Drain Plan, Project No. 2, by Moffatt and Nichol dated March, 1969 ' This plan provides for ultimate or existing drains in the Fontana, east Rancho Cucamonga, and north unincorporated County areas. Drains proposed in this plan will connect primarily to the San Sevaine Channel and Upper Etiwanda Creek Channel. 39 B. City of Rancho Cucamonga Comprehensive Storm Drain Master Plan, by L. D. King dated June, 1981 This plan provides for drainage in City of Rancho Cuca- monga industrial area to the Day Creek Channel. C. Victoria Development Project in Rancho Cucamonga This development project provided a drainage plan for draining the area generally north of the Devore Freeway, south of Highland Avenue, and west of Etiwanda Avenue to the Day Creek Channel. D. Ontario Industrial Partners Development Project in Ontario This development project provided a drainage plan for draining the Ontario Industrial Park area south of the San Bernardino Freeway and west of Milliken Avenue to the Day Creek Channel and /or Wineville Basin. E. Mulberry Channel This existing channel is located north of the San Bernar- dino Freeway and east of the San Sevaine Channel. The facility drains the area between the San Bernardino Freeway and the Santa Fe Railroad, and west of Sierra Avenue to the San Sevaine Channel. F. DeClez Channel This partially existing and proposed channel is located north of the Jurupa Hills. The facility will drain the area between the Jurupa Hills and the San Bernardino Freeway to the San Sevaine Channel. G. West Fontana Channel This existing unimproved channel is located north of the Santa Fe Railroad between the San Sevaine Channel and Sierra Avenue. It drains the general area between the railroad and Baseline Avenue to the San Sevaine Channel. 40 H. Hawker - Crawford Channel This existing unimproved channel is located north of the Devore Freeway and drains a portion of the area north of the Devore Freeway to the San Sevaine Creek System. The channel systems cross railroads in several locations. Where new crossing structures are required, it is assumed a by -pass or "shoofly" will be required. The by -pass track costs are included in the cost estimates. The proposed channels will cross under the existing California Transportation Department freeways and highways without re- quiring new structures, with one exception. A new structure will be required at Foothill Boulevard and the San Sevaine Channel. New structures will be required at several County and City roads and streets. It is assumed that costs of detours and traffic control are covered in the construction contingency allowance. Possible interferences with large buried utilities will be minimal and believed to be complete as of the date of this report. However, a final thorough check must be made prior to construction of any system. The profiles show only inter- secting interferences, and not necessarily all information on any paralleling utilities. The hydraulic design criteria presented in Section II should be applied in final design planning unless otherwise approved by the San Bernardino County Flood Control District. The various features of certain reaches of each channel system are described in succeeding pages, and final problems to be solved in final design are discussed. The preliminary plan and profile sheets are included in Volume II of this report. 41 2. DAY CREEK CHANNEL SYSTEM A. General The Day Creek Channel System, including Lower Etiwanda Creek, has a total drainage area of approximately 22 square miles at Riverside Basin. The Drainage Plan map is in- cluded in this report and shows the proposed system align- ment, total drainage area, sub - system drainage areas, and the system design flows at various points along the route. Refer to Figure No. 1 for a schematic depiction of the proposed system. The drainage study and report includes that portion of the system in Riverside County from Riverside Basin to the Pomona Freeway. This plan connects to and coordinates with the Riverside County Flood Control and Water Con- servation Drainage Plan immediately south of the Pomona Freeway. The description of the system herein starts at the San Gabriel Mountains and proceeds southerly to the Pomona Freeway. Each sub - system is shown on the enclosed drainage map and is described herein. The preliminary plan sheets, showing the alignment, profiles, channel sections, and design flows are included in Volume II of this report. Lower Etiwanda Creek Channel from Wineville Basin to the San Bernardino Freeway is considered to be part of the Day Creek Channel System. 42 B. Day Creek Debris Dam The drainage area for Day Creek at the canyon mouth is approximately 3,042 acres (4.75 square miles). A debris dam with a storage capacity of approximately 500,000 cubic yards of debris is proposed (based on 100,000 cubic yards of debris per square mile of drainage area). The debris dam has a design height of approximately 55 feet. The Cucamonga County Water District has intake tunnels located in the canyon mouth that intercept low flows and groundwater. Because of these intake facilities, the debris dam site was located below the canyon mouth. An additional constraint on the location of the dam site is the Cucamonga Fault Zone located above the powerlines. A "Reconnaissance Geotechnical Investigation" report has been prepared by Moore & Taber. The reconnaissance report is on file in the Flood Control District office. The report recommends a structure setback from the fault of 75 feet south of the defined fault zone and 400 feet north of the fault zone. The preliminary dam site has been located above the recommended setback line and below the Cucamonga County Water District water intake facilities. A detailed geotechnical and soils investigation is recom- mended during the design stage for final dam siting and design criteria. The preliminary debris dam site is shown on the Drainage Plan map located in this report and on the preliminary plan and profile sheets. The plan and profile sheets are in Volume II of this report. 43 The Day Creek Spreading Grounds are located immediately below the proposed debris dam. A combined turnout and basin drain is proposed for the debris dam to direct impounded flows to the spreading grounds for water con- servation purposes. Because of the substantial area of the spreading grounds and its water conservation potential, a larger turnout is recommended to pass some flood flows through the dam and into the spreading grounds during flood periods, as well as flows stored by the dam after the storm has subsided. A turnout into the spreading grounds from the channel is also provided. The turnouts from the dam and channel are shown on the plans. A "Water Conservation Report" was also prepared as a part of the Drainage Plan. Water conservation plans are described in more detail in that report. The following possible interferences in utilities, road crossings and private right -of -way or easements must be recognized in the final siting and design of the debris dam and pertinent structures: The Cucamonga County Water District intake lines and tunnels within the canyon mouth. The Cucamonga County Water District trans- mission line on the east bank of the creek. The referenced utility lines and the fault zone traces and recommended structure setback lines are shown on the plan. The debris dam will be located within District fee or easement right -of -way and no additional right -of -way will have to be acquired. 44 C. Day Creek Channel 1) Reach from Debris Dam to Highland Avenue A rectangular concrete channel is proposed from the debris dam to Highland Avenue along the east side of the spreading grounds. A rectangular channel is recom- mended because of the high channel velocities above Highland Avenue and the rocky terrain within the spreading ground area. Although a trapezoidal channel is less expensive under normal circumstances, it would be impractical in this case due to the rocky terrain and difficulty in controlling flows. The design flow between the debris dam and Highland Avenue is 5,310 cfs. The channel cross - section for this reach varies from a bottom width of 16 feet and depth of 9 feet to a bottom width of 16 feet and 10.75 feet. The preliminary channel plans are included in Volume II of this report and show the alignment, channel section, design flow, and channel velocities. A 772 -inch reinforced concrete pipe and structure is proposed to conduct storm flows through the debris dam and into the spreading grounds. The turnout is shown on the plan and profile sheets and on the water con- servation plans. A spillway conducting excess flows from the spreading grounds back into the channel is shown on the plans. A 48 -inch outlet pipe from the channel into the spreading grounds is also proposed. 45 The following possible interference in utilities, road crossings and private right -of -way or easement must be recognized in the final design of the facilities: The 12 -foot in diameter MWD Foothill Feeder crossing the spreading grounds in an east - west direction approximately 2,700 feet north of Highland Avenue. The City of Los Angeles Department of Water and Power powerline corridor below the canyon mouth.. The SCE powerline easement. The Cucamonga County Water District waterline south of the MWD Feeder. The channel will be located within the District fee or easement right -of -way and no additional right -of- way will have to be acquired. 2) Reach from Highland Avenue to the Devore Freeway A 55 -foot wide, 10 -foot deep rectangular channel exists from the Highland Avenue bridge downstream for approxi- mately 100 feet. This channel can be extended upstream through the bridge without reconstructing, the bridge. The existing channel below the short reach of concrete channel is an earth channel with revetted sides. A trapezoidal concrete lined channel is proposed from the existing concrete channel to the Devore Freeway channel structure at Arrow Route. The design flow between Highland Avenue and the Devore Freeway is 6,214 cfs. The channel section varies from a bottom width of 12 feet and depth of 10 feet to a bottom width of 20 feet and depth of 10 feet. There are several transitions at grade changes and connections to struc- tures at street crossings. 46 The PERR has a bridge crossing the existing channel approximately 4,000 feet south of Highland Avenue. The proposed channel section will pass under the existing bridge between the piers, and the construction of a new structure at the railroad should not be necessary. A dip section exists at the Base Line Road crossing of the existing channel. A 24'W x 10'H x 70'L RCB, or its equivalent, is proposed. An existing bridge on pilings exists at the Foothill Boulevard crossing of the existing channel. A rectangu- lar channel can be constructed under the bridge between the pilings without reconstructing the bridge. Transi- tions will be necessary upstream and downstream of the bridge to connect to the proposed trapezoidal channel. A dip section exists at the Arrow Route Road crossing of the existing channel. A 40'W x 8'H x 80'L RCB, or its equivalent, is proposed for this crossing. A 50 -foot wide, 10 -foot deep channel exists under the Devore Freeway crossing of the existing channel. The existing channel starts immediately below the Arrow Route Road crossing. A transition is proposed to connect the Arrow Route Road RCB to the existing concrete channel. Adequate channel right -of -way exists for this reach and no additional right -of -way is necessary. The following possible interferences in utilities, road crossings and private right -of -way or easements must be recognized in final design of the facilities: 47 The PERR Bridge. The 41 -inch SBVMWD waterline at Base Line Road. The road crossings at Base Line Road, Foothill Boulevard, and Arrow Route Road. A 2 -inch waterline at Foothill Boulevard. A 36 -inch gas line at Arrow Route. A 3 -inch and 16 -inch waterline at Arrow Route. A 4 -inch gas line at Arrow Route. A telephone cable at Arrow Route. An 8 -inch waterline 1,300'± north of Arrow Route. The following existing or proposed lateral storm drains must be recognized at the final design stage: A proposed 90 -inch storm drain from the west at Arrow Route. A proposed 57 -inch storm drain from the east along the Devore Freeway. The existing double, 8'x 5' RCB and concrete channel crossing Arrow Route and entering the existing channel north of the Devore Freeway. A proposed 48 -inch storm drain from the west at Foothill Boulevard. A proposed 63 -inch storm drain from the west at Baseline Road. A proposed 72 -inch storm drain from the west at the PERR. The above referenced utilities and ,storm drains are shown on the plans. The channel will be constructed within existing District right -of -way and no additional right -of -way will be required. 48 The existing Day Creek Basin is located below Highland Avenue on the west side of the channel. A turnout from the channel to the basin, a basin drain, and a spillway from the basin to the channel must be part of the final design plans. The existing and proposed facilities are shown on the preliminary plan and profile sheets. There are also plans showing the existing basin and proposed basin expansion. The basin plans and water conservation aspects are discussed in detail in the Water Conservation Report. The basin plans are also included in Volume II of this report. 3) Reach from the Devore Freeway to the San Bernardino Freeway A 50 -foot wide by 10 -foot deep channel exists under the Devore Freeway. A trapezoidal concrete lined channel is proposed from the existing channel to and through the San Bernardino Freeway. The design flow in the reach between the Devore Freeway and the San Bernardino Freeway is 7,375 cfs. The channel section for this reach varies from a bottom width of 12 feet with a 12.5 foot depth to a bottom width of 50 feet with a 7 -foot depth. The extreme variation in bottom width is due to grade restrictions. The preliminary channel plans are included in Volume II of this report and shows the alignment, channel section, design flow, and channel velocities. The Santa Fe Railroad has a bridge crossing approximately 2,000 feet south of the Devore Freeway. A 50 -foot wide rectangular channel 8 feet deep and 40 feet long is pro - 49 posed under the railroad. The channel section will fit between the existing railroad bridge piers without modification of the bridge. Transitions will be neces- sary at each end of the rectangular channel section due to the change to a trapezoidal channel section. Approximately 1,000 feet south of the Santa Fe Rail- road crossing, the 12 -foot diameter Metropolitan Water District of Southern California Upper Feeder crosses the existing earth channel. The proposed trapezoidal channel will pass over the top of the existing transmission line. A transition (drop struc- ture) will be required immediately south of the MWD line because of the necessary grade change. A private road crossing exists approximately 4,000 feet north of San Bernardino Avenue. The existing bridge is a narrow wooden bridge and will have to be replaced unless the road can be closed on each side of the channel. A 30'W x 10'H x 30'L RCB, or its equivalent, is proposed for this crossing. A dip section exists at the San Bernardino Avenue crossing of the existing channel. A 36'W x 10'H x 100'L RCB, or its equivalent, is proposed for this crossing. A transition (drop structure) will be necessary down- stream of the RCB because of the grade change in the channel. A transition structure will be required up- stream to connect the RCB to the proposed trapezoidal channel. A dip section exists at the Colton Avenue ( "G" Street) crossing of the existing channel. A 30'W x 9'H x 80'L RCB, or its equivalent, is proposed for this crossing. A transition (drop structure) will be necessary down- stream of the RCB because of the grade change in the 50 channel. A transition structure will be required up- stream to connect the RCB to the proposed trapezoidal channel. An existing 8 -inch waterline will have to be relocated at this location. The proposed channel section will pass under the San Bernardino Freeway between the bridge piers without alteration of the bridge or piers. There is an existing earth channel that confluences with the Day Creek Channel on the west side, immediately above the freeway. An 84 -inch RCP lateral connection to the channel is proposed from the east, north of the freeway. Adequate channel right -of -way exists for this reach and no additional right -of -way is necessary. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized in final design of the facilities: The Devore Freeway and the existing concrete channel under the freeway. The Santa Fe Railroad bridge crossing and two 21 -inch sewerline crossings at the Santa Fe Railroad. An 8 -inch waterline at the Santa Fe Railroad. The 8 -foot diameter MWD Upper Feeder crossing south of the Santa Fe Railroad. An 8 -inch and 16 -inch oil line south of the MWD pipeline. A 4 -inch and 10 -inch waterline crossing at the private road crossing south of the MWD line. A telephone line at the private road crossing. An 18 -inch sewerline crossing at San Bernardino Avenue. A 27 -inch sewerline crossing at Colton Avenue. 51 An 8 -inch waterline crossing at Colton Avenue (to be relocated). A 36 -inch gas line located adjacent to the right - of -way line at Colton Avenue. The following existing or proposed lateral storm drains must be recognized at the final design stage: A 5 -foot wide by 3.5 feet deep channel lateral from the east, north of the Santa Fe Railroad (M&N Line 17e) . A channel connection (existing earth channel) from the west, north of the San Bernardino Freeway (M&N Line 19a). A proposed 84 -inch RCP lateral from the east, north of the San Bernardino Freeway (M&N Line 19c). The above referenced utilities and storm drains are shown on the plans. The channel will be constructed within existing District right -of -way and no additional right -of -way will be necessary. 4) Reach from the San Bernardino Freeway to Wineville Basin The design flow in the reach between the San Bernardino Freeway and Wineville Basin is 8,156 cfs. The existing channel between the freeway and Slover Avenue (Airport Drive) is an unrevetted earth channel. An earth channel with rail and wire revetted sides exists from Airport Drive to Wineville Basin. A rectangular concrete lined channel is proposed from the San Bernardino Freeway through the Southern Pacific Railroad to Slover Avenue (Airport Drive). The channel bottom width varies from 26 feet to 30 feet, and the depth varies from 14 feet to 13 feet. A trapezoidal 52 concrete lined channel is proposed from Slover Avenue to Wineville Basin. The channel section for this reach varies from a bottom width of 12 feet with a 12.5 -foot depth, to a 34 -foot bottom width and 10.25 -foot depth. The preliminary channel plans are included in Volume II of this report and shows the alignment, channel section, design flow, and channel velocities. The Southern Pacific Railroad has a bridge crossing approximately 1,000 feet south of the San Bernardino Freeway. The existing bridge will have to be replaced and a 30'W x 12'H x 40'L RCB, or its equivalent, is proposed for the new structure. A 30'W x 12'H x 90'L RCB, or the equivalent, is pro- posed for the street crossing at Slover Avenue (Airport Drive). A dip section exists at this channel crossing at the present time. Transitions will be necessary north and south of the proposed RCB to connect to the proposed channel. There is an existing RCB structure where Jurupa Street crosses the channel. Transitions exist north and south of the box culvert, connecting the culvert to the existing earth channel. It is proposed to retain the transitions as part of the new channel system. The existing culvert crossing is shown on the plans. The Day Creek Channel flows into Wineville Basin approx- imately 1,500 feet south of Jurupa Street. The basin serves as a flow- through basin, and has a 700 acre -feet storage capacity. A drop structure spillway will outlet Day Creek Channel flow into the basin. The basin plans are included with the channel plan and profile sheets in 53 Volume II of this report. Further discussion on the water conservation aspects of the basin are covered in the Water Conservation Report. An existing spillway at the approximate center of the south levee of the basin outlets flows into the existing revetted earth channel. The existing basin outlet spillway will be modified or be replaced to provide for the design flow. The basin plans indicate the basin will be deepened approximately seven feet (7'). Lower Etiwanda Creek Channel also outlets into Wineville Basin. Etiwanda Channel is discussed below. Adequate channel and basin right -of -way exists for this reach and no additional right - of-way is necessary. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized in final design of the facilities: The SPRR crossing. A "shoofly" will be neces- sary for construction of the structure. The road crossing at Slover Avenue (Airport Drive). A proposed 8 -inch sewer crossing the channel approximately 50 feet north of Wineville Basin. The following existing or proposed lateral storm drains must be recognized at the final design stage: An existing 12'x 8' RCB inlet into the northwest corner of Wineville Basin. A proposed 60 -inch lateral inlets into the north side of Wineville Basin. 54 The above referenced utilities and storm drains are shown on the plans. 5) Reach from Wineville Basin to Riverside Basin The design flow in the reach between Wineville Basin and Riverside Basin is 9,260 cfs. The existing channel between the two basins is a revetted earth channel. A trapezoidal concrete lined channel with a bottom width of 16 feet and a depth of 13.5 feet is proposed. Patton Road (Philadelphia Avenue) presently crosses the existing channel in a dip section. A grouted stone spillway outlet flows into Riverside Basin. A 36'W x 10'H x 72'L RCB, or the equivalent, is proposed for the road crossing. A basin inlet spillway is pro- posed to outlet channel flows into Riverside Basin. A transition will be necessary north of the proposed RCB to connect to the proposed channel. It is proposed to deepen and further develop Riverside Basin as shown on the plans for flood storage and water conservation purposes. The basin plans are included with the channel plan and profile sheets in Volume II of this report. The deepening of Wineville and River- side Basins will provide for the increase in runoff to be generated by future upstream development and provide important facilities for water conservation. Further discussion on the water conservation aspects of the basin are covered in the Water Conservation Report. Adequate channel and basin right -of -way exists for this reach and no additional right -of -way is necessary. 55 The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized in final design of the facilities: A proposed 36 -inch CBMWD Fontana Intercept to be located at the lower end of the Wine - ville Basin outlet spillway. An existing 36 -inch HP gas line at Patton Road. An existing 24 -inch sewerline at Patton Road. The SCE transmission towers in Riverside Basin. 6) Reach from Riverside Basin to the Pomona Freeway The design flow in this reach is 9,720 cfs. Day Creek exists as an earth ditch between the Riverside Basin and the Pomona Freeway. The ditch is inadequate and serious erosion has occurred. The existing ditch parallels the Union Pacific Railroad and spur trackage and passes under the Pomona Freeway in a triple 5'x 5' RCB. The existing RCB is not adequate to handle large storm flows and ponding and overflow have occurred in the past. There are two locations where railroad spur tracks cross the ditch. One spur crosses by a wooden trestle and the other crossing has two 60 -inch CMP's to pass storm flows under the spur track. The existing ditch and structures are shown on the plans. A rectangular spillway is proposed for the outlet of Riverside Basin. A combination of rectangular and trapezoidal concrete lined channel is proposed from the Riverside Basin outlet to the Pomona Freeway. The rectangular channel varies from a channel with a 50 -foot bottom width and 9.5 -foot depth to a 50 -foot bottom width 56 and 10.5 -foot depth. The trapezoidal channel varies from bottom width of 20 feet and 11.50 -foot depth to a bottom width of 30 feet and 12.25 -foot depth. A 40'W x 10'H x 70'L RCB and a 40'W x 10'H x 20'L RCB, or their equivalents, are proposed for the spur track crossings. A triple 14'x 12' RCB is proposed to pass flows under the Pomona Freeway and the railroad tracks. The reach from the Pomona Freeway to Riverside Avenue exists as a natural drainage course at the present time. A trapezoidal channel 20 feet wide and 11.25 feet deep is proposed for the reach. A 40'W x 10'H RCB, or its equivalent, is proposed for the crossing at Riverside Drive. The Riverside County Flood Control and Water Conserva- tion District has prepared a drainage plan for Day Creek south of the Pomona Freeway. This drainage plan has been coordinated with that plan and will tie to it at Riverside Drive. The triple 14'x 12' RCB will cross under the UPRR tracks, adjacent spur tracks, Mission Boulevard, and the Pomona Freeway overhead structures. The RCB will have to be aligned and designed to miss the freeway bridge piers. A detailed survey will be necessary during the final design stage to exactly locate the bridge piers. 7) Wineville and Riverside Basins As indicated in Section 11,4, Wineville and Riverside Basins will provide 700 acre -feet and 1,100 acre -feet 57 of water conservation storage respectively. Although it was decided not to route -down channel design flows due to the storage, the basin will act as interim flood storage and flow regulation facilities in the interim period, if the basins are constructed prior to the construction of the downstream channel. As indicated in Section VII, the development of Wine - ville and Riverside Basins, Lower Etiwanda Creek Channel, and Day Creek Channel from Riverside Basin to the Devore Freeway is recommended as a 1st Phase Project. A 72 -inch basin drain has been provided as a part of the plans to drain Wineville Basin and assist in regulating flood flows through the basin. The 72 -inch basin drain will be constructed as part of the 1st Phase Project. The 72 -inch drain in conjunction with the existing 36 -inch drain will empty the basin within 24 hours, thus providing capacity for back to back storms, should they occur. The 1st Phase Project of the regional plans includes the expansion of Riverside Basin to provide a water conservation and flood storage volume of 1,100 acre - feet. As a part of the 1st Phase Project, a 48 -inch CMP drain is proposed to drain the approximate upper seven feet (7') of the basin. The storage and drain will provide a degree of flood flow regulation in the event of back to back storms. 58 D. Lower Etiwanda Creek Channel The proposed Lower Etiwanda Creek Channel will extend southwesterly from the San Bernardino Freeway just west of Etiwanda Avenue to Wineville Basin. An existing 38'x 10' culvert and 8'x 4' culvert pass flows under the freeway. Flows then proceed southerly through a wooden trestle bridge under the Southern Pacific Railroad to Airport Drive. There is an existing trapezoidal concrete channel between Airport Drive and Santa Ana Avenue, with culverts under Airport Drive and Santa Ana Avenue. Because of the limited capacity of the existing channel, culverts under Airport Drive and Santa Ana Avenue and the limited flow through the SPRR trestle, the design flow for Etiwanda Channel was established at 3,500 cfs. Due to the capacity limitation of the existing channel and other cost savings discussed in other sections of this report, it was decided to ul- timately direct Upper Etiwanda Creek flows to the San Sevaine Creek Channel. Therefore, there is no channel recommended for Etiwanda Creek flows between the Devore Freeway and the San Bernardino Freeway. The drainage in the area between the freeways will be handled by storm drains. Refer to Figure No. 1 and the Drainage Plan Hydrology Map for the proposed channels for Upper and Lower Etiwanda Creek. A trapezoidal concrete lined channel is proposed below Santa Ana Avenue, except through the curve where a rectangu- lar channel is proposed. The trapezoidal channel section varies from a bottom width of 16 feet and a depth of 7 feet to a bottom width of 26 feet and a depth of 7.25 feet. The rectangular channel has a bottom width of 32 feet and a depth of 8 feet. A trapezoidal channel is also proposed from Airport Drive north to the San Bernardino Freeway. 59 The existing structure under the SPRR is a wooden trestle with limited capacity. It is recommended to replace this bridge with a 32'W x 6.5'H x 60'L RCB, or the equivalent. A bypass track (shoofly) will be necessary to construct the proposed bridge structure and keep the railroad in operation. A four barrel 16' x 6' RCB is proposed at Jurupa Avenue. This structure is proposed to be constructed in the near future and is shown on the plans as existing. There is a 36 -inch HP gas line, a 10 -inch sewerline, and a 15 -inch sewerline that parallel the east levee of Wine - ville Basin. It is proposed to lower the gas line and sewerlines. The channel will outlet into Wineville Basin as shown on the plans. If the gas line and sewerlines can be relocated, it will be possible to outlet into the basin with an open channel and spillway (drop structure). If the 36 -inch HP gas line cannot be relocated, it will be necessary to outlet into the basin with a closed conduit. Because of the high water level in the basin, it would be desirable to outlet at the higher elevation. The plans are shown with the gas and sewer lines to be lowered. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized in the final design of the facility: The SPRR north of Airport Drive. An existing 10 -inch waterline and an existing 8 -inch sewerline in Airport Drive. 60 An existing 27 -inch sewerline in Jurupa Avenue. The 300 -foot wide SCE corridor and transmission line paralleling the proposed channel. The existing 36 -inch high pressure gas line and the 10 -inch and I5 -inch sewerlines that parallel the east side of Wineville Basin. The following existing or proposed lateral storm drains must be recognized at the final design stage: A 63 -inch RCP from the west is pro- posed at Jurupa Avenue. A 60 -inch RCP from the east is pro- posed at Jurupa Avenue. A 57 -inch RCP from the east at Santa Ana Avenue. A 60 -inch RCP from the east at Air- port Drive. The above referenced utilities and storm drains are shown on the plans. The channel will follow the existing Southern California Edison corridor. A 65 -foot wide right -of -way is necessary for the proposed channel and must be acquired. Because the Etiwanda Creek Channel outlets into Wineville Basin, it is considered to be part of the Day Creek System. 61 3. SAN SEVAINE CREEK CHANNEL SYSTEM A. General The San Sevaine Creek Channel System, including Upper Etiwanda Creek and the smaller foothill drainage courses tributary to San Sevaine Creek, has a total drainage area of approximately 60 square miles at the Pomona Freeway. The Drainage Plan map is included in this report and shows the proposed system alignment, total drainage area, sub- system drainage areas, and the system design flows at various points along the route. For purposes of this report, the lower end of the drainage area is shown at the Pomona Freeway, just south of the San Bernardino- Riverside County Line. That portion of the San Sevaine Creek Channel in Riverside County has been designed by the Riverside County Flood Control and Water Conservation District and is covered in a separate report. However, the two plans have been coordinated, using the same hydrology and design flows. Because the channel system is complex, the description of the system herein starts at the San Gabriel Mountains and proceeds southerly to the County Line. Each sub- system is shown on the enclosed drainage map and is described herein. The preliminary plan sheets, showing the alignment, profiles, channel sections, and design flows, are included in Volume II of this report. The Upper Etiwanda Creek Channel, from the canyon mouth to the existing channel under the Devore Freeway, is considered to be part of the San Sevaine Creek Channel System. The proposed plan calls for confluencing Etiwanda Creek and San Sevaine Creek flows at the downstream end of the existing 62 parallel concrete lined channels under the Devore Freeway. Refer to the plan and profile sheets for the location of the existing channels and the proposed connection points. Figure No. 1 provides a schematic depiction of the channel system alignment and drainage area. B. Etiwanda Debris Dam and Channel The drainage area for Etiwanda Creek at the canyon mouth is approximately 1,953 acres (3.05 square miles). A debris dam with a storage capacity of approximately 300,000 cubic cubic yards of debris is proposed (based on 100,000 cubic yards of debris per square mile of drainage area). The debris dam has a design height of 45 feet, based on the preliminary plan. Because of the Cucamonga Fault Zone, the proposed dam site is located below the canyon mouth. A "Reconnaissance Geotechnical Investigation" report has been prepared by Moore & Taber and is on file in the Flood Control District office. The report recommends a structure setback line from the fault of 75 feet south of the defined fault zone and 400 feet north of the fault zone. This limitation requires a dam siting south of the canyon mouth, north of the powerline. A detailed geotechnical and soils investi- gation is recommended during the design stage for final dam siting and design criteria. Because of the fault zone and the lack of confinement of flows, the siting of the dam site is difficult. The preliminary debris dam site is shown on the preliminary plan and profile sheets in Volume II of this report. The 63 general location of the dam site is also shown on the Drainage Plan map. Design criteria and debris basin analysis are discussed in more detail in Section IV. The schematic location of the proposed channel and debris dam is shown on Figure No. 1. A rectangular concrete channel is proposed from the debris dam to the existing channel under the Devore Freeway. A rectangular channel is recommended because of the high channel velocities and rocky terrain. Although a trape- zoidal channel is usually less expensive under normal circumstances, it would be impractical in this case due to the rocky terrain. The design flow between the debris dam and 24th Street is 3,080 cfs and 5,290 cfs from 24th Street to the existing channel under the Devore Freeway. The rectangular channel varies in size from a bottom width of 12 feet and a depth of 7.25 feet to that of a bottom width of 18 feet and a depth of 9.5 feet. A dip section exists at the location where Etiwanda Creek crosses Summit Avenue. A double 10'W x 10'H x 70'L RCB is proposed at the crossing. Transitions will be necessary upstream and downstream of the RCB to connect to the channel. The preliminary channel plans are included in Volume II of this report and show the alignment, channel section, design flow, and channel velocities. The Etiwanda Spreading Grounds are located west of the pro- posed channel, north of Summit Avenue. A 36 - inch RCP turnout from the channel will conduct flows to the spreading grounds for water conservation purposes. An overflow spillway from the spreading grounds back into the channel will be necessary. 64 The turnout from the channel is shown on the plans. A "Water Conservation Report" was also prepared as a part of the Drainage Plan. Water conservation plans are described in more detail in that report. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized in the final design of the facilities: The Los Angeles Department of Water and Power transmission line located immediately south of the preliminary debris dam site. The Southern California Edison transmission line located south of the preliminary debris dam site and north of Summit Avenue. The MWD 96 -inch Foothill Feeder at the future 24th Street alignment. The referenced utility lines, the fault zone traces, and the recommended structure setback lines are shown on the plans. The proposed channel will be located almost totally within Flood Control District fee or easement right -of -way and very little additional right -of -way will be necessary for channel construction. The proposed debris dam is located partly within District right -of -way. Some additional right - of -way for the debris dam will be necessary. C. San Sevaine Creek - Canyon Mouth to Summit Avenue The drainage area for San Sevaine Creek at the canyon mouth is approximately 1,273 acres (1.99 square miles). The recommended plan does not include a debris dam and concrete channel for San Sevaine Creek flows above the Devore Freeway. 65 However, a debris dam and concrete lined channel is shown on the plans as an alternative. The recommended plan for San Sevaine Creek is a reception type levee from the canyon mouth to Summit Avenue. The design flow at the canyon mouth is 1,967 cfs. The proposed reception channel has a bottom width varying from 25 feet to 100 feet and•a levee 20 feet in height. A reception type channel exists from Summit Avenue to approximately 3,200 feet north of Summit Avenue. The proposed reception channel is an extension of the existing channel and levee. Because of the existing spreading ground area west of the proposed channel above Summit Avenue, and the large basin area below Summit Avenue, the debris and channel velocities can be handled without a debris dam and concrete lined channel. However, an alternate concrete channel and debris dam is shown on the preliminary plans. The channel alignment, cross - section, design flow, and design velocities are shown on the preliminary plans. The spreading ground north of Summit Avenue is recommended to be maintained as a water spreading area and left in its natural condition. The MWD Foothill Feeder crosses the San Sevaine Creek Channel approximately 2,500 feet north of Summit Avenue. The 96 -inch pipeline crosses the spreading grounds north of Summit Avenue diagonally. The line is shown on the, plans. The pipeline is deep and will not conflict with the proposed facilities. A Los Angeles Water and Power transmission line and a Southern California Edison transmission line cross the San Sevaine Creek Channel and the spreading grounds. The Cucamonga Fault Zone is located in close proximity to the alternate debris dam location. A detailed soils investi- gation and geotechnical study will be necessary if it is decided to construct the debris dam. 66 The existing Henderson Canyon Channel and Levee and the Morse Canyon natural flowpath are shown on the preliminary plans. A realignment of Henderson Canyon Channel is pro- posed and is shown on the plans. Henderson and Morse Canyon flows can be joined north of Summit Avenue and conducted under Summit Avenue in one structure. The realignment of the Henderson Canyon Channel will be cost effective by limiting the number of structures at Summit Avenue and will improve the engineering efficiency of the present alignment. Although not a part of this study, an unimproved or semi - improved reception type channel is proposed for Henderson Canyon Channel. Due to the large spreading ground area available, a reception channel and levee can be designed to handle the design flow and keep the area in as much of a natural condition as possible and still sustain flood flows. Other than those mentioned above, there are no other known utility conflicts with the project. The Chino Basin Munici- pal Water District has a permit for turning flows out of the MWD Foothill Feeder and spreading the flows in the basins to the south. The proposed plan will have no significant effect on the water spreading activity, and in fact, is designed to enhance water conservation. The proposed facilities will be located within Flood Control District fee or easement right -of -way and no additional right - of -way will have to be acquired. D. San Sevaine Creek - Summit Avenue to Devore Freeway A large flood storage and water conservation basin (the Lower San Sevaine Basin) is proposed immediately upstream 67 of the Devore Freeway. The basin spillway will connect to the existing channel under the Devore Freeway. Refer to Figure No. 1 and the Drainage Plan and hydrology map in this report. The design flow at the connection to the existing concrete lined channel is 4,100 cfs. The Lower San Sevaine Basin has a flood storage capacity of 1,720 acre -feet. This storage capacity has been utilized in the revised hydrology and the downstream channel has been sized accordingly. The Lower San Sevaine Basin is included in the preliminary plans in Volume II of this report. The Drainage Plan proposes a series of water conservation basins between Summit Avenue and the Devore Freeway. The San Sevaine Basin Nos. 1, 2, 3 and 4 are located on line with the San Sevaine Channel immediately below Summit Avenue. These basins are flow- through basins and have a total maximum dead storage volume to top of proposed spillways of 440 acre -feet. The grouted stone spillways should be designed to pass the design flow through the basins with a minimum 2 -foot freeboard. Henderson Canyon and Morse Canyon flows also enter the San Sevaine Basins at Summit Avenue. Immediately downstream of the San Sevaine Basins a larger water conservation and flood storage basin is proposed. This basin is called the Lower San Sevaine Basin and has a static storage volume of 1,720 acre -feet. The basin is on line with San Sevaine Creek Channel and will be a flow- through basin. As indicated above, the storage capacity of the basin was considered in sizing the downstream channel. The existing basin and proposed expanded basin are both shown on the plans. The existing basin actually exists 68 as a wide earth channel with a spillway that outlets into the existing concrete lined San Sevaine Creek Channel under the Devore Freeway. It is proposed to extend the existing spillway as shown on the preliminary plans. The existing basin drain is a 36 -inch RCP. It will be necessary to add a parallel drain to effectively drain the proposed basin. Hawker - Crawford Channel inlets into San Sevaine Basin No. 3. The channel inlet is shown on the plans. It will be neces- sary to modify the inlet to the basin when the basin is deepened. There are no known utility conflicts in this reach. The basins will be located within District fee or easement right -of -way and no additional right -of -way will have to be acquired. E. San Sevaine Channel - Devore Freeway to San Bernardino - Riverside County Line At the time the Devore Freeway was constructed, the Cali- fornia Transportation Department constructed parallel concrete lined channels under the freeway for Etiwanda and San Sevaine Creek flows. The channels were constructed adjacent to each other and parallel, but as separate facili- ties so as not to comingle the flows. After the channels pass under the freeway, the separate flows are conducted back to their historical flowpaths. During the Phase I preparation stage of this study, it was decided to conduct the Upper Etiwanda Creek flows to the proposed San Sevaine Creek Channel at the Devore Freeway. The connection of Etiwanda Creek flows to the San Sevaine 69 Creek Channel can be accomplished at the south end of the existing parallel channels. The combining of the channels at this point will eliminate the necessity of maintaining two channels below the freeway and is more economical. Refer to the Phase I Report, "Day, Etiwanda and San Sevaine Creek Drainage Plan ", by Bill Mann & Associates dated December, 1981, for a more detailed analysis of the pro- posed combining of Etiwanda Creek and San Sevaine Creek flows. The existing parallel channels under the Devore Freeway are adequate to handle the design flow for Etiwanda Creek and San Sevaine Creek. Refer to the preliminary plans in Volume II of this report for details on the existing facilities. 1) Reach from the Devore Freeway to Baseline Avenue Parallel but separate trapezoidal channels exist under the Devore Freeway for Etiwanda Creek and San Sevaine Creek flows. After the channels pass under the freeway system, the flows are directed back to their respec- tive historical flowpaths. As indicated above, it is proposed to combine Etiwanda and San Sevaine Creek flows immediately south of the Devore Freeway. From the Devore Freeway southerly, the combined system will be known as the San Sevaine Creek Channel. The design flow between the Devore Freeway and Base Line Avenue is 8,200 cfs. A trapezoidal concrete lined channel is proposed for this reach. The channel section varies from a channel bottom width of 10 feet and a 12.5 -foot depth to a bottom width of 12 feet and a depth of 12 feet. A transition will be necessary at the south side of the freeway (Victoria Street) to combine the two existing channels,and connect them to the proposed chan- nel. The existing channels, the proposed transition, 70 and the proposed channel sections and profile are shown on the plans in Volume II of this report. A small 8'x 4' RCB presently conveys flows under the PERR. The existing culvert is inadequate and will have to be. replaced. A double 14'x 12'x 30' RCB, or its equivalent, is proposed for this crossing. A bypass track (shoofly) may be necessary during construction to keep the track in operation. Transitions will be neces- sary to connect the proposed channel to the culvert. Base Line Avenue presently crosses the existing channel in a dip section. A triple 14'x 12'x 70' RCB is proposed for this crossing. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized during the final design stage: The PERR crossing. The 41 -inch SBVMWD transmission line crosses the channel at Base Line Avenue. The following existing or proposed lateral storm drains must be recognized during the final design stage: A proposed 60 -inch RCP lateral from the west at Victoria Street. A proposed 11.5'x 8.5' RCB lateral from the east at Base Line Avenue. The above referenced utilities and proposed storm drains are shown on the plans. The channel will be constructed within existing District right -of -way and no additional right -of -way is required. 71 2) Reach from Base Line Avenue to Foothill Boulevard The design flow from Base Line Avenue to Foothill Boule- vard is 12,200 cfs. The existing channel in this reach is an earth channel with revetted sides. A trapezoidal concrete lined channel is proposed in this reach. The channel section varies from a bottom width of 14 feet and a depth of 12.75 feet to a bottom width of 16 feet and a depth of 13 feet. Because of the alignment curvature at Foothill Boulevard and the necessary skew of the proposed RCB, a rectangular channel is proposed immediately upstream and downstream of the RCB. The rectangular channel will have a bottom width of 30 feet and depth of 13 feet. A transition will be required to connect the trapezoidal and rectangu- lar channel. The existing earth channel ends at Foothill Boulevard. An existing culvert conducts the channel flows under Foothill Boulevard and into a natural drainage course. The proposed channel alignment follows the existing 200 -foot wide Flood Control District right -of -way between Hickory Avenue and Ilex Avenue, south of Foot- hill Boulevard. A triple 14'W x 12'H x 100'L RCB is proposed to conduct channel flows under Foothill Boule- vard. The proposed structure will replace the inade- quate existing 25'x 4.5'x 120' RCB. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized during the final design stage: A 36 -inch gas line crossing approximately 3,000 feet north of Foothill Boulevard at future Miller Street. 72 A 12 -inch waterline crossing the proposed channel approximately 3,500 feet north of Foothill Boulevard. The following existing or proposed lateral storm drains must be recognized during the final design stage: A proposed 54 -inch RCP from the east at future Miller Street. • The above referenced utilities and proposed storm drains are shown on the plans. The channel will be constructed within existing District right -of -way and no additional right -of -way is required. 3) Reach from Foothill Boulevard to the West Fontana Channel (SFRR) The design flow from Foothill Boulevard to the West Fontana Channel confluence is 12,200 cfs. There is no existing channel within this reach. However, the Flood Control District does own a 200 -foot wide right -of -way along the proposed alignment acquired several years ago in anticipation of a Federal flood control project. The proposed alignment lines up with the existing channel north of Foothill Boulevard and the existing channel south of the West Fontana Channel confluence. Therefore, the alignment is consistent with prior plans of the District for a channel in this location. A trapezoidal concrete lined channel is proposed for this reach, except for short stretches of rectangular channel. The trapezoidal channel section has a bottom width of 16 feet and a depth of 13 feet. As indicated above, a short reach of rectangular channel is proposed 73 immediately below the Foothill Boulevard structure be- cause of the channel curvature. A triple 14'W x 12'H x 70'L RCB is proposed for the Arrow Highway road crossing. Because there is no existing channel along this alignment, the existing Arrow Highway crossing is at grade. There are three barrel 18'W x 12.5'H RCB's proposed at Whittram Avenue and the Santa Fe Railroad. Because of the short reach between the street and railroad, a 40 -foot wide, 12.75 -foot deep rectangular channel is proposed between the structures. A bypass track (shoofly) will be necessary during the construction of the rail- road structure to keep the railroad in operation. The West Fontana Channel confluences with the proposed San Sevaine Creek Channel immediately south of the Santa Fe Railroad. The West Fontana Channel is a main lateral channel for the area, extending east to the Sierra Avenue area. Below the railroad and the West Fontana Channel confluence, the San Sevaine Creek Channel exists as an earth ditch, approximately 30 feet wide and 13 feet deep. A partially developed basin exists immediately east of the channel alignment, south of the Santa Fe Railroad. This basin, known as Hickory Basin, presently serves as the terminus of the West Fontana Channel. The West Fontana Channel passes through the basin and into the San Sevaine Creek Channel. The basin is shown on the plans. The Flood Control District has a plan for the future improvement of the West Fontana Channel and Hickory Basin. The plans included in Volume II of this report also show the future alignment of the West 74 Fontana Channel and its confluence with the San Sevaine Creek Channel. The future final design of San Sevaine Creek Channel must take into consideration the design of the future improvement of the West Fontana Channel. Adequate right -of -way exists for the improvement of the San Sevaine Creek Channel and the West Fontana Channel. The following possible interferences in utilities, road crossings, and private right -of -way or easements must be recognized during the final design stage: The Arrow Highway street crossing. The Whittram Avenue crossing. The Santa Fe Railroad crossing. A bypass track (shoofly) will be necessary. The following existing or proposed lateral storm drains must be recognized during the final design stage: The existing and future improvement of the West Fontana Channel and Hickory Basin and the confluence with the San Sevaine Creek Channel. 4) Reach from the West Fontana Channel to the San Bernardino Freeway The design flow from the West Fontana Channel to the San Bernardino Freeway is 15,550 cfs. San Sevaine Creek exists as an earth ditch in this reach with an approxi- mate 25 -foot bottom width and a 12 to 13 -foot depth. The existing ditch is located within a Flood Control District 200 -foot wide right -of -way. A trapezoidal concrete lined channel is proposed in this reach. 75 Approximately 1,000 feet south of the Santa Fe Railroad, the MWD Foothill Feeder crosses the existing channel. The large pipeline has a 5 -foot grouted stone pad placed over the pipeline. The channel is designed to pass over the pipeline and protection pad without disturbing the facility. The pipeline is shown on the plans. A transition (drop structure) will be required immediately downstream of the pipeline because of the grade change. Because of the necessary change in grade, a rectangular channel is proposed for a short distance downstream of the MWD transmission line crossing. Approximately 3,500 feet south of the Santa Fe Railroad crossing, a railroad spur track and two service roads cross the existing channel. The railroad spur track bridge is approximately 16 feet wide, and the service road bridges are approximately 30 feet wide. The bridges are on piles at approximately 15 -foot spacing. Because of the spacing of the piles, it will be diffi- cult to construct a channel without replacing the bridges. For that reason, the preliminary plans show the existing bridges to be replaced with triple 16'W x 10.0'H RCB's. During the final design stage, further investigation should be made to see if the channel can be constructed under the existing bridges without disturbing the bridge decks. The cost estimate for the project is based on having to replace the bridges. The existing channel cross - section, existing bridges, and proposed bridge replacements are shown on the plans. Approximately 400 feet and 1,200 feet upstream of San Bernardino Avenue, two other railroad spur tracks cross the existing channel. These bridges also have piling supports of 15 -foot spacing. For purposes of this plan 76 and cost estimating, the replacement of the bridges with triple 16'W x 12'H x 20'L RCB's are proposed. and cost estimating, the replacement of the bridges with triple 16'W x 12'H x 20'L RCB's are proposed. Similar to those bridges discussed above, further in- vestigation should be made during the final design stage to see if the channel can be constructed without replacing the structures. There is an existing 4 -12' x 6' RCB at the San Bernardino Avenue crossing of the existing channel. The existing culvert does not have adequate capacity to handle the design flow and is not at the proper grade. It is pro- posed to replace the structure with a triple 16'W x 12'H x 70'L RCB. There is also an existing railroad spur track immediately south of San Bernardino Avenue. The bridge is on piling supports at 15 -foot spacing. If it is necessary to re- place the bridge for channel construction, a triple 14'W x 12'H x 20'L RCB is proposed. The San Sevaine Creek Channel below San Bernardino Avenue exists as an earth channel approximately 48 feet wide with a 12 -foot depth. The existing channel cross - section is shown on the plans. Valley Boulevard is located approximately 400 feet north of the San Bernardino Freeway. There are three 66 -inch CMP's under Valley Boulevard to pass San Sevaine Creek flows. A triple 16'W x 12'H x 80'L RCB is proposed at this location to replace the existing CMP's. Transition structures will be necessary to connect the structure to the proposed trapezoidal channel. 77 Immediately downstream of Valley Boulevard, between the San Bernardino Freeway and Valley Boulevard, is located the Mulberry Channel. Mulberry Channel extends east from the San Sevaine Creek Channel to Sierra Avenue. The channel is located north of the San Bernardino Free- way for its entire length and drains the area between the West Fontana Channel and the freeway. The channel exists as a trapezoidal concrete channel and outlets into the San Sevaine Creek Channel just north of the freeway. The Mulberry Channel, freeway bridge structures, and proposed connection to the San Sevaine Creek Channel are shown on the plans in Volume II of this report. The Mulberry Channel and its tributary drainage area is also shown on the Drainage Plan Hydrology Map included in this report. The existing San Sevaine Creek Channel flows pass under the San Bernardino Freeway in a grouted stone lined channel approximately 72 feet wide and 5 feet deep. There are bridge piers located in the middle of the channel. Mulberry Channel outlets into San Sevaine Creek Channel in a curved rectangular channel. The Mulberry Channel outlet directs flows downstream, east of the freeway bridge center piers. It is proposed to pass the San Sevaine Creek flows under the freeway structure in two parallel rectangular channels. The east channel will intercept Mulberry Channel flows, and the two parallel channels will confluence into one channel immediately south of the freeway. It will be necessary to have a streamlined nose separator upstream of the freeway at the location where the flow is split into two channels. A rectangular channel is proposed between the freeway and Valley Boulevard. A more detailed hydraulic analysis will be necessary at the 78 final design stage to provide a confluencing structure for the connection of Mulberry Channel to San Sevaine Creek Channel. Aside from constructing the channel under the bridge structures, the freeway will not be affected. The following interferences in utilities, road and railroad crossings, and private right -of -way or ease- ments must be recognized during the final design stage: The MWD Foothill Feeder below the Santa Fe Railroad. Three Kaiser Steel railroad spur tracks that cross the channel between San Bernar- dino Avenue and the Santa Fe Railroad. One Kaiser Steel railroad spur track crossing south of San Bernardino Avenue. Two Kaiser Steel service roads that cross the channel north of San Bernardino Avenue. A 16 -inch oxygen line, an 8 -inch nitrogen line, and a 3 -inch hydrogen line that parallel the west right -of -way line. (Several of the lines cross the channel on the service road bridges.) CBMWD 12 -inch and 15 -inch sewerlines that cross the channel at San Bernardino Avenue within 48 -inch steel casing. The San Bernardino Avenue crossing. The Valley Boulevard crossing. An 8 -inch gas line at San Bernardino Avenue. A 16 -inch waterline at San Bernardino Avenue. A 6 -inch sewer force main at San Bernar- dino Avenue. A telephone conduit at San Bernardino Avenue. 79 The following existing or proposed lateral storm drains or channels must be recognized in the final design stage: The West Fontana Channel and Hickory Basin south of the Santa Fe Railroad. The Mulberry Channel north of the San Bernardino Freeway. The proposed 12'W x 7.5'H rectangular channel (M & N 22A) from the west, north of the San Bernardino Freeway. The above referenced utilities, crossings, and storm drain laterals are shown on the plan. The channel will be located within existing Flood Control District right -of -way and no additional right -of -way will have to be acquired. 5) Reach from the San Bernardino Freeway to the Jurupa Basin The design flow from the San Bernardino Freeway to the Jurupa Basin is 18,850 cfs. The San Sevaine Creek Channel in this reach is an earth channel approximately 100 feet wide and 5 feet deep with revetted sides. The existing channel cross - section is shown on the plans. The existing channel is located within a Flood Control District 200 -foot wide right -of -way. The Southern Pacific Railroad crosses the channel approx- imately 700 feet south of the San Bernardino Freeway. The existing channel flows are conducted under the rail- road by five 72 -inch CMP's. A triple 18'W x 12'H x 60'L RCB is proposed on the preliminary plans for the railroad crossing. Because of the rectangular channel under the San Bernardino Freeway, a 40 -foot wide, 13 feet deep 80 rectangular channel is proposed for the reach between the freeway and the SPRR. A bypass track (shoofly) will be necessary during construction of the crossing to keep the railroad in operation. A trapezoidal concrete lined channel is proposed down- stream of the SPRR crossing. The channel section varies from a 20 -foot bottom width with a 14 -foot depth section to that of a 24 -foot bottom width with a 14.50 -foot depth. Stover Avenue crosses the channel approximately 750 feet south of the Southern Pacific Railroad in a dip section with five 48 -inch CMP's that conduct small flows under the road section. A triple 18'W x 12'H x 90'L RCB is proposed for this crossing. The Jurupa Water Conservation Basin is located on the east side of the channel at Jurupa Street. The basin has a storage capacity of approximately 1,300 acre -feet and will be used jointly for flood flow storage and water conservation. The basin will be designed as a bypass basin with an over -side channel spillway designed to divert the peak flow out of the channel for storage. A spillway is proposed to outlet excess flows back into the channel. The basin will also have storm drains out - letting into the basin, draining the area northeast of the basin. The basin plans are included in Volume II of this report. The water conservation aspects of the basin are covered in more detail in the "Water Conservation Report ". The following interferences in utilities, road crossings, and private right -of -way or easements must be recognized during the final design stage: 81 A 12 -inch waterline at Slover Avenue. A 4 -inch oil line at the S.P.R.R. (relocate). The road crossing at Slover Avenue. The S.P.R.R. crossing. The following existing or proposed lateral storm drains must be recognized in the final design stage: An existing 36 -inch RCP lateral from the west just north of Jurupa Basin. An existing 36 -inch CSP lateral from the east, north of Jurupa Basin. The above referenced utilities, crossings, and storm drain laterals are shown on the plans. The channel will be located within existing Flood Control District right -of -way and no additional right -of -way is necessary. 6) Jurupa Basin As indicated above, Jurupa Basin has been designed as a bypass basin. The channel design flow above the basin is 18,850 cfs, and the channel design flow below the basin is 12,100 cfs. The difference in the design flow is taken care of by the 1,300 acre -feet of storage in the basin. The basin is designed as a bypass system with a pro- posed over -side spillway approximately 1,200 feet long to remove the peak flow from the channel. The basin will have a spillway to direct excess flows back to the channel. 82 Because of capacity limitations in the existing down- stream channel and a desire to decrease the size of the future downstream channel, the proposed design and hydrology was developed with assistance from the River- side County Flood Control and Water Conservation District. The over -side spillway necessary to make the bypass system work will require detailed hydraulic computer modeling in the design stage. The basin partially exists, and adequate right -of -way is available for the necessary basin expansion. There is a proposed 102 -inch drain shown in the 1969 Moffat and Nichol report that will outlet into the northeast corner of the basin. The preliminary basin plans are included in Volume II of this report. The water conservation aspects of the basin are covered in more detail in the "Water Conser- vation Report ". As indicated in Section VII, Construction Sequence, the development of Jurupa Basin is a part of the recommended 1st Phase construction on the San Sevaine Creek System. Jurupa Basin was added to the recom- mended 1st Phase along with the Lower San Sevaine Basin to provide storage capacity to offset increased runoff from upstream development. Because Jurupa Basin will function as a bypass system, it will not provide storage capacity for smaller floods unless the basin can be designed to intercept small channel flows in the interim period. It is therefore recommended that the channel outlet be designed to outlet small flood flows into the basin until the 83 downstream channel is constructed. This can be accom- plished by omitting a part of the splitter wall that would be constructed with the proposed overside channel spillway. It will require a detailed analysis in the design stage, but it is believed the basin can be designed to receive small channel flows in the interim period. 7) Reach from the Jurupa Basin to San Bernardino- Riverside County Line The design flow from the Jurupa Basin to the County Line is 12,100 cfs. The existing San Sevaine Creek Channel in this reach is an earth channel approximately 85 feet wide and 8 feet deep. The existing channel is located within a Flood Control District right -of -way varying from 150 feet to 180 feet in width. A trapezoidal concrete lined channel is proposed with a bottom width of 20 feet and a depth of 13 feet. As indicated above, that portion of the channel bypassing the basin is rectangular due to the necessary bypass spillway and basin outflow spillway. Marlay Avenue crosses the channel approximately 2,500 feet south of the basin. The crossing exists as a partial dip section with a battery of seven (7) RCP's. A triple 14'W x 12'H x 70'L RCB is proposed for the crossing. The Riverside County Flood Control and Water Conserva- tion District is designing the channel from the San Bernardino - Riverside County Line southerly. The drainage plans have been coordinated and are compatible. 84 The following interferences in utilities and road crossings must be recognized in the final design of the channel: The 36" sewer transmission line proposed by Chino Basin Municipal Water District along Marlay Avenue. The channel will be located in existing Flood Control District right -of -way. 85 SECTION VI CONSTRUCTION COST ESTIMATES 1. GENERAL The cost estimates provided below are separated into the two basic channel systems. The Day Creek Channel System includes Lower Etiwanda Creek, and the San Sevaine Creek Channel System includes Upper Etiwanda Creek. The cost estimate is broken down into reaches within each system, corresponding to the reaches shown on the hydrology map and described in Section V on plan discussion. The unit prices used in the construction cost estimates are listed below. The unit prices are based on best information derived from recent or present ongoing construction projects, including Corps of Engineers' projects and Flood Control District projects. Table VI -1 Cost Estimate Unit Prices Debris Dams Clear site and remove obstructions (LS) $200,000 Excavation 2.50 /CY Embankment 2.50 /CY Spillways (LS) 250,000 Miscellaneous (LS) 50,000 20% construction contingency - Geotechnical and soils investigation 35,000 Construction design (ASCE Curve) - Day Creek 150,000 Construction design (ASCE Curve) - Etiwanda Creek 107,000 Channel Construction Clearing and removal 14,000 /MI Channel excavation 2.25/CY Channel concrete (slope paving) 120 /CY Channel concrete (rectangular channel) 225/CY Reinforcement steel 0.40 /LB Channel cutoff wall (longitudinal) 4.00 /LF Chain link fence 7.00 /LF Bridges, RCB's, Transitions, etc. Class "A" concrete 225/CY Structure excavation 7.50 /CY Structure backfill 10 /CY 86 The unit prices and estimates are based on November, 1982 prices when the ENR Index was 4533. To update them, multiply by the ratio of the current ENR Index to 4533. The construction con- tingency factor used for concrete lined channel and structure construction was 10 %. The contingency factor includes such items as necessary utility relocations, side drain connections, necessary subdrainage facilities, minor paving and earthwork at the channel crossings, and other miscellaneous or unknown items. The cost estimates include channel fencing with a 6 -foot chain link fence with appropriate gating. A construction contingency factor of 20% was used in estimating the cost of the debris dams. The construction design estimate for the debris dams was based on the ASCE Curves. The geotechnical and soils investigation cost estimate for the debris dams was based on an analysis and estimate by a reputable geotechnical- engineering firm. A. Day Creek Channel System 1) Day Creek Debris Basin (Height = 55') Subtotal $ 1,827,655 20% Contingency 365,531 Subtotal 2,193,186 Geotechnical /Soils Investigation & Report 35,000 Engineering,Inspection & Administration 150,000 Estimated Total 2,378,186 USE 2,375,000- 87 2) Debris Basin to Highland Avenue (L = 14,400') Subtotal $ 5,009,742 5% Contingency 250,487 Subtotal 5,260,229 15% Engineering, Inspection & Administration 789,034* Estimated Total 6,049,263 USE 6,050,000 %'r Includes Inspection & Administration of debris basin construction. 3) Highland Avenue to Arrow Route (L = 13,400') Subtotal $ 2,525,383 10% Contingency 252,538 Subtotal 2,777,921 15% Engineering, Inspection & Administration 416,688 Estimated Total 3,194,609 USE 3,200,000 4) Arrow Route to San Bernardino Freeway (L = 11,280') Subtotal $ 2,302,738 10% Contingency 230,274 Subtotal 2,533,012 15% Engineering, Inspection & Administration 379,952 Estimated Total 2,912,964 USE 2,925,000 5) San Bernardino Freeway to Wineville Basin (L = 8,515') Subtotal $ 2,513,468 10% Contingency 251,347 Subtotal 2,764,815 15% Engineering, Inspection & Administration 414,722 Estimated Total 3,179,537 USE 3,200,000 88 6) Wineville Basin to Riverside Basin (L = 2,620') Subtotal $ 694,082 10% Contingency 69,408 Subtotal 763,490 15% Engineering,Inspection & Administration 114,523 Estimated Total 878,014 USE 875,000 7) Riverside Basin to Riverside Avenue (L = 6,555') Subtotal $ 3,640,516 10% Contingency 364,052 Subtotal 4,004,568 15% Engineering,Inspection & Administration 600,685 Estimated Total 4,605,253 USE 4,625,000 8) Etiwanda Creek Channel - Wineville Basin to San Bernardino Freeway (L - 7,750') Subtotal $ 2,317,394 10% Contingency 231,739 Subtotal 2,549,133 15% Engineering,Inspection & Administration 382,370 Estimated Total 2,931,503 USE 2,950,000 9) Day Creek Spreading Grounds Subtotal $ 1,000,001 5% Construction Contingency 50,000 5% Engineering, Inspection & Administration 52,500 Estimated Total 1,102,501 USE 1,100,000 89 10) Day Creek Basin Subtotal $ 2,264,000 5% Construction Contingency 113,200 5% Engineering, Inspection & Administration 118,860 Estimated Total 2,496,060 USE 2,500,000 11) Wineville Basin Subtotal $ 2,395,573 5% Construction Contingency 119,779 5% Engineering, Inspection & Administration 125,768 Estimated Total 2,641,121 USE 2,650,000 12) Riverside Basin Subtotal $ 5,309,793 5% Construction Contingency 265,490 5% Engineering, Inspection & Administration 278,764 Estimated Total 5,854,047 USE 5,850,000 DAY CREEK SYSTEM TOTAL $38,300,000 C. San Sevaine Channel System 1) Upstream End to Summit Avenue (L = 6,105') Subtotal $ 1,120,017 5% Contingency 56,001 Subtotal 1,176,018 15% Engineering,Inspection & Administration 176,403 Estimated Total 1,352,421 USE 1,350,000 90 2) Devore Freeway to Baseline (L = 2,085') Subtotal $ 881,202 10% Contingency 88, 120 Subtotal 969,322 15% Engineering,Inspection & Administration 145,398 Estimated Total 1,114,720 USE 1,125,000 3) Baseline to West Fontana Channel (L = 11,346') Subtotal $ 4,272,734 10% Contingency 427,273 Subtotal 4,700,007 15% Engineering,Inspection & Administration 705,001 Estimated Total 5,405,008 USE 5,425,000 4) West Fontana Channel to San Bernardino Freeway (L = 8,205') Subtotal $ 3,780,779 10% Contingency 378,078 Subtotal 4,158,857 15% Engineering,Inspection & Administration 623,828 Estimated Total 4,782,685 USE 4,800,000 5) San Bernardino Freeway to Jurupa Basin (L = 4,275') Subtotal $ 1,741,782 10% Contingency 174,178 Subtotal 1,915,960 15% Engineering,Inspection & Administration 287,394 Estimated Total 2,203,354 USE 2,200,000 91 6) Jurupa Basin to Riverside -San Bernardino County Line (L = 8,270') Subtotal $ 3,028,816 107 Contingency 302,882 Subtotal 3,331,698 15% Engineering,Inspection & Administration 499,754 Estimated Total 3,831,452 USE 3,850,000 7) Etiwanda Creek Debris Dam (Height =45' ) Subtotal $ 1,498,993 20% Contingency 299,799 Subtotal 1,798,792 Geotechnical /Soils Investigation & Report 35,000 Engineering, Inspection & Administration 107,000 Estimated Total 1,940,791 USE 1,950,000 8) Etiwanda Creek - Debris Dam to Summit Avenue (L = 7,775') Subtotal $ 2,245,475 10% Contingency 224,548 Subtotal 2,470,023 15% Engineering,Inspection & Administration 370,503 Estimated Total 2,840,526 USE 2,850,000 9) Etiwanda Creek Channel - Summit Avenue to Devore Freeway (L = 3,750') Subtotal $ 1,113,942 10% Contingency 111,394 Subtotal 1,225,336 15% Engineering,Inspection & Administration 183,800 Estimated Total 1,409,137 USE 1,425,000 92 10) San Sevaine Basins 1 thru 4 and Lower San Sevaine Basin Subtotal $ 9,010,800 57, Construction Contingency 450,540 5% Engineering, Inspection & Administration 473,067 Estimated Total 9,934,407 USE 9,950,000 11) Jurupa Basin Subtotal $ 5,380,270 5% Construction Contingency 269,014 5% Engineering, Inspection & Administration 282,464 Estimated Total 5,931,749 USE 5,950,000 SAN SEVAINE SYSTEM TOTAL $40,875,000 DAY CREEK SYSTEM TOTAL 38,300,000 GRAND TOTAL $79,175,000 93 SECTION VII CONSTRUCTION SEQUENCE 1. GENERAL The sequence of construction of the various reaches should be dictated primarily by the need for protection and resolving downstream runoff problems in both San Bernardino and Riverside Counties. The priority listing herein was developed by a com- bination of recommendations by the Technical Committee and the various agencies involved with the plan. The priority listing is in fact based on,the necessity of con- structing downstream channel facilities first to provide the necessary outlet for upstream construction. Where it is possible to provide a storage basin, a change in the construction sequence is possible. It should be recognized the recommended priority for construction will change periodically because of funding limitations, proposed large development projects, and population trends. Because of these changing factors, the construction priority should be re- viewed on an annual basis and modified as necessary. The following principles should be considered in modifying or establishing channel construction priority: a) The basic purpose of channel construction should be based on flood protection and reduction of down- stream runoff problems. 94 b) Channels that direct flows to water conservation or storage basins should be given higher priority, other considerations being equal. c) Where existing natural or semi - improved channels are reasonably adequate, those reaches should not be improved over other areas until their tributary areas are developed to the extent that they require improved facilities to carry the increased runoff. d) If funding for a specific channel system or specific reach within a channel system is made available due to development projects or possible Federal or State financing, that reach could be constructed regardless of priority if the funds cannot be shifted to other areas. 2. RECOMMENDED PRIORITIES BY SYSTEM A. Day Creek System 1) Development of Riverside and Wineville Basins, Lower Etiwanda Creek Channel, and the Day Creek Channel from Riverside Basin to the Devore Freeway Estimated Cost = $18,450,000 2) Day Creek Channel from the Devore Freeway to Highland Avenue, the Day Creek Debris Dam, and Day Creek Basin Estimated Cost = $ 8,075,000 95 3) Day Creek Channel from Highland Avenue to the Debris Dam, and the development of the Day Creek Spreading Grounds Estimated Cost = $ 7,150,000 4) Day Creek Channel from Riverside Basin to Riverside Drive Estimated Cost = $ 4,625,000 Total Cost Day Creek System = $38,300,000 B. San Sevaine Creek System 1) Development of the Lower San Sevaine Basin, San Sevaine Basins, Jurupa Basin, and approximately 2,600 feet of channel at Jurupa Basin to make basin function Estimated Cost = $17,125,000 2) San Sevaine Creek Channel from just south of the Santa Fe Railroad to the Devore Freeway Estimated Cost = $ 6,550,000 3) Etiwanda Creek Debris Dam and Etiwanda Creek Channel from debris dam to the Devore Freeway Estimated Cost = $ 6,225,000 4) San Sevaine Creek Channel from the Riverside -San Bernardino County Line to the Santa Fe Railroad (see Note on following page) Estimated Cost = $ 9,625,000 96 5) San Sevaine Creek reception levee and channel from Summit Avenue to the LAWP power line Estimated Cost = $ 1,350,000 Total Cost San Sevaine Creek System = $40,875,000 TOTAL COST DAY CREEK AND SAN SEVAINE CREEK SYSTEMS = $79,175,000 Note: These estimates are based on November, 1982 prices when the Engineering News Record Index was 4533. To update them, multiply by the ratio of the current ENR Index to 4533. It should be noted the construction sequence recommended does not include necessary channel facilities in River- side County. However, the Drainage Plan has to be viewed as an overall drainage plan for both Counties as was originally intended. Therefore, because of the necessary coordination with the Drainage Plan portion in Riverside County and necessary coordination with future channel construction in Riverside County, it may not be possible to construct the reach of channel below the Jurupa Basin, until channel construction is accomplished in Riverside County. 97 APPENDIX 1. References 2. Hydrologic Analysis of the Day Creek/ San Sevaine Watersheds in the County of San Bernardino REFERENCES 1. Williamson and Schmid, "A Hydrologic Analysis of the Day Creek/ San Sevaine Watersheds in the County of San Bernardino, June, 1982 2. Williamson and Schmid, "Progress Report on Day Creek /San Sevaine Channel Hydrology Study ", April, 1982 3. Riverside County Flood Control and Water Conservation District, "Hydrology Manual ", 1978 4. San Bernardino County, "Hydrology Manual ", Draft, January, 1983 5. Los Angeles County Flood Control District, "Hydraulic Design Manual" 6. Los Angeles County Flood Control District, "Debris Dams and Basins Design Manual." 7. Department of the Army, Corps of Engineers, "Hydraulic Design of Flood Control Channels ", 1970 8. Fred E. Tatum, U. S. Army Engineer District, Los Angeles, "A New Method of Estimating Debris - Storage Requirements for Debris Basins ", 1963 9. State of California, Department of Water Resources, Division of Safety of Dams, "Statutes and Regulations Pertaining to Super- vision of Dams and Reservoirs ", 1970 10. "Debris /Retention Basins - Day and Etiwanda Creeks, Reconnais- sance Geotechnical Investigation ", by Moore and Taber, Con- sulting Engineers and Geologists, 1981 11. Bill Mann & Associates, "Day, Etiwanda and San Sevaine Creek Drainage Plan, Water Conservation Report ", March, 1983 12. Bill Mann & Associates, "Funding Mechanisms for the Day, Etiwanda and San Sevaine Creek Drainage Plan ", March, 1983 A HYDROLOGIC ANALYSIS OF THE DAY CREEK /SAN SEVAINE WATERSHEDS IN THE COUNTY OF SAN BERNARDINO ESPECIALLY PREPARED FOR BILL MANN AND ASSOCIATES OUR JOB NO. 80278.40 JUNE 3, 1982 17782 SKY PARK BOULEVARD • IRVINE, CALIFORNIA 92714 • (714) 549 -2222 TABLE OF CONTENTS SECTION TITLE PAGE NUMBER INTRODUCTION Study Purpose 1 Project Staff 1 II. STUDY PROCEDURE 2 III. DISCUSSION OF RESULTS Peak Flow Rates 5 Critical Storm Patterns: Comparisons 5 Critical Storm Patterns: As A Function of Watershed Area 8 IV. REFERENCES 13 0 0 0 Z Z 0 2 J -JJ_ TABLE OF CONTENTS LIST OF FIGURES FIGURE NUMBER TITLE 1 DAY CREEK /SAN SEVAINE CHANNEL WATERSHED BOUNDARIES 2 WATERSHED POINTS OF CONCENTRATION 3 NOAA ATLAS 2, 1 -HOUR ISOHYETALS 4 NOAA ATLAS 2, 6 -HOUR ISOHYETALS 5 NOAA ATLAS 2, 24 -HOUR ISOHYETALS 6 OCEMA 3 -HOUR CRITICAL STORM PATTERN RAINFALL RELATIONS 7 NOAA ATLAS 2 DEPTH -AREA CURVES 8 OCEMA CRITICAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA 9 RCFCD CRITICAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA 10 SBCFC CRITICAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA 11 PEAK RAINFALL AND PEAK RUNOFF CORRELATION TO SBCFC VALUES 0 r U 0) O Z Q Z 0 - 7 TABLE OF CONTENTS LIST OF TABLES TABLE NUMBER TITLE I. UNIT HYDROGRAPH PEAK FLOWRATE ESTIMATES II. HYDROLOGY MODEL WATERSHED PARAMETERS III. THREE - COUNTY CRITICAL STORM PATTERN COMPARISONS IV. RAINFALL DATA AND DEPTH -AREA FACTORS V. PEAK MODELED 1 -HOUR RAINFALL VI. PEAK MODELED 1/2 -HOUR RAINFALL a z 0 V) a Z Q Z 0 V) 2 Q J J >_ TABLE OF CONTENTS LIST OF APPENDICES NUMBER TITLE LETTER FROM RCFCD REGARDING DAY CREEK WATERSHED HYDROLOGY PARAMETERS 0 0 0 Z Z 0 J -JJ I. INTRODUCTION STUDY PURPOSE The main objectives of this study are threefold: (i) Determine 100 -year peak runoff flows for the Day Creek and San Sevaine Channel using the Riverside County Flood Control District (RCFCD) hydrology manual methodology. The method used is to determine unit - hydrographs between the most upstream watershed point and specified downstream points of concentration. This procedure, along with the various parameter information (see Table II) was approved by the RCFCD for use in a previous Day Creek Study (Bill Mann and Associates, 1981). (ii) Determine 100 -year peak runoff flows for the Day Creek and San Sevaine Channel using the recently developed San Bernardino County Flood Control (SBCFC) unit - hydrograph methodology. This procedure will be briefly outlined in a following section of this report. (iii) Examine the differences in peak runoff values determined in items (i) and (ii) above. Besides comparing hydrograph peak values, the major differences in methodology will be examined. Additionally, runoff peak flows generated by the Orange County Environmental Management Agency (OCEMA) unit - hydrograph methodology will also be developed for comparison purposes. Computer simulation results for the dozens of hydrograph studies prepared for this report are contained in a TECHNICAL REPORT which is on file at Williamson and Schmid. Consequently, the current study will only address key hydrology issues, and will summarize in tabular form the computer modeling results developed during this project. PROJECT STAFF Key project engineers involved in this study include: 0 Ted Hromadka, Ph.D., P.E. Mark Seits, Hydrologist en 0 z z 0 80278.40 - 6 -2 -82 1 -' II. STUDY PROCEDURE The procedure used in this hydrology study is composed of several tasks described in the following: (1) Identify and Verify the Total Watershed Boundary. This task was completed by Bill Mann and Associates and includes the identification of ultimate land development. Also incorporated into this task is the modification of the watershed boundary as determined by the proposed diversion plans developed by Bill Mann for both the Day Creek and San Sevaine Creek Systems. Figure (1) shows the planned watershed boundaries for both major creek systems. (2) Locate Watershed Points of Concentration. The objective of this task is to identify locations within each watershed where runoff quantities are required. The identification of watershed concentration points was determined by Bill Mann and Associates (Figure 2). (3) Determine Hydrology Methodology. Generally, either a Rational Method or Unit - Hydrograph Method is used for hydrology studies of a watershed. Due to the size of the subject watersheds, the unit - hydrograph approach is used to determine peak flow rates and the time - distribution of runoff at each point of concentration. Because both subject watersheds cross jurisdictional boundaries into Riverside County, the RCFCD unit - hydrograph method was used for a previous study of Day Creek (Bill Mann and Assoc., 1981) prepared by Williamson and Schmid. Additionally, the existing SBCFC Hydrology Manual did not provide a methodology adequate for the analysis of the subject watershed hydrology; consequently, the RCFCD procedures were used in the earlier study. Following the first Day Creek study, the Day Creek watershed was redefined and another hydrology study was necessary. Williamson and Schmid prepared a "PROGRESS REPORT ON DAY CREEK /SAN SEVAINE CHANNEL HYDROLOGY STUDY" dated April 20, 1982, which presented unit - hydrograph computer modeling results for the new Day Creek watershed and for the planned San Sevaine Channel system. U cn Recently, SBCFC completed an in -depth analysis of unit- Z hydrograph methodologies and developed a new county procedure for use in hydrology studies. This procedure is based o co 2 80278.40 - 6-2 -82 2 3 r n `r . " \ sr 21 � 7 0 ' A r / c- '''i \r ) � " 1e�.- f-- r t .. _ / ..- J, ... / " .. -...... ' ; : - _ / - - \ _ . _ 1 - - \ -�- -�! ` �v`�` N. `� \ vr. vJ `� \� — - / _ _ -.7..... \ r W `� SCALE ....��.. .._ ,\ \` 1" =9000' _ \ U ` � ^ \ 1 ■ 1 — tiV� - \ ` 1 ` r �nr� \ \— _ ` 1 1 �1 r -cr',/ , / ) ,... ti � G— ) / J i FIGURE 1. DAY CREEK /SAN SEVAINE CHANNEL WATERSHED BOUNDARIES �_ . ') \..i t I ( L.i_. 0 1 r ©l 2200f , , - `--ir c F- .l_.x•,- ..- }� �- 1600,, / O ,, J , f 152 . \ AREA DELETED / ` ` N. DUE TO 1440 . . �. _ RETARDATION '`- ` r A O _. ` - -- 4' 4 N \ . .c__"_ Air 1, — © `80 - - / _ \ -- _ ..- ,..• -I -� 1 �2 `� 8 �- 0 3 i — — ---. — ...0. , . " *s- \ 17 . � ■ . 9 — -1e..■.,---= SCALE ,. - -� _ _ _ \ -11pp \ N y 1" = 9000' `�� A ,.,.. { 11 j \ -'` — Q NODE NUMBER �O p FOR DAY CREEK \ ° �-e — �„ 0 NODE NUMBER .. Y \_^..i..— ` �� SAN SEVAINE • iii 0Q P /7.- �' \ .� 9 \ 0 1� CHANNEL L. n_�^ ti \P 8S0 �G- r l ) O , FIGURE 2. WATERSHED POINTS OF CONCENTRATION on the well known methodologies of the Counties of Los Angeles, Orange, Riverside, and San Diego, but incorporates a highly accurate distribution of recorded peak watershed rainfall intensities in the modeled critical storm pattern. Due to the advent of the SBCFC unit - hydrograph procedure, a comparative study was initiated wherein the SBCFC and RCFCD unit - hydrograph results are compared for both the planned Day Creek and San Sevaine watersheds. In this current study, the results of this comparative analysis are given along with hydrograph results from a third methodology based on the current OCEMA Hydrology Manual (1980). (4) Determine Hydrology Watershed Parameters. The unit - hydrograph methodology requires the following information: (i) watershed geometric data (ii) average watershed rainfall values (iii) average watershed soil loss rate values (iv) average watershed basin flow factors Item (i) is determined directly from the watershed map of Figure (2). Item (ii) is determined by the usual weighted averaging procedures for rainfall information obtained from the NOAA Atlas 2. This Atlas is the rainfall data base for both the RCFCD and the new SBCFC hydrology methodologies. Figures (3), (4), and (5) show the watershed 1 -hour, 6 -hour, and 24 -hour isohyetal values as obtained from the NOAA Atlas 2. Items (iii) and (iv) are based on values determined appropriate by RCFCD for the Day Creek Watershed in the previous Day Creek Study (Bill Mann, 1981). To be consistent, the RCFCD approved parametric values are used in the current study. A letter from RCFCD specifying parametric values is contained in Appendix I of this report. For modeling based on the RCFCD methodology, a weighted average of "S" curves (see hydrology manuals) was stipulated by the RCFCD (Appendix I), and was used in the current study. For the OCEMA and SBCFC methodologies, a weighted average was also used identical to the RCFCD approach. (5) Determine Peak Runoff Values. Peak 100 -year storm runoff o values are determined at each point of concentration in Figure z 0 2 80278.40 - 6 -2 -82 3 ♦ ` •1 1 -‘• ` ■ ` . ♦ . � • ` 1 \ � N \ \ • \ 2.6 "- ∎/ . ♦ 1 • • • ` 2.5" ---• N. ' 1 ` • 2.4 "_ / ♦ ` - 1 � • 1 1 2.3" - - 1 i t t - - 1 2.2 "- - --- -- - --- -- -�.� / / i t / 2.1" , � / 1 t f 2. - / 1.9" ,_ . -_- -- / 1.8 " -- -- -- / t r / 1.7" / / i 1.6 " - - - - -- __ -_ ___�._ - - - -- t I t t t 1.5------ .5 " -- L '� ■ t r 4' 1 . . / • / , t 1 N t i � � ~/ `` • /, r 1.4" � ..� SCALE ■ • 1 = 9000' ■ ■ 1 1 1 1.3 " "- , ■ ■ ■ -. 4 ■ 4' 1.2 " " -- - i_. / 4♦ - .� ■ FIGURE 3. NOAA ATLAS 2, 1 -HOUR LSOHYETALS • • .\ ♦ ♦♦ • \\ N. \; \\ • • • • \ S • \\ • • r r , \ . \\ \\ • \` ^ • \ • `, ...� � ` \ 8 .0'' - ' �"'' -- 1 1 • X / ! t 1 6.5" / / 1 -- 1 6.0 " ----- -- - - i .... i � r� °� r r ..- ' 5 .0" ....... r� - r - r - .� r .�. r - r r ^ ' / / ■ I 'r I - -" -- r r ✓ r - 4.5"- ._.c O.. -.... r '- ••••• + - r r �' ------ 1 / / Sil . I SCALE • 1": 9000' ,- - 3.5" � - • • • X X � .-""♦ t 1 �� 'ter i /' ...• / 1 I i i 1 / 3.0" � t ` 1 / \ ♦ ....... gym. fir. FIGURE 4. NOAA ATLAS 2, 6 -HOUR ISOHYETALS • ' . . / 1 N � � � 22 " - --- � � � � . / ■ 20" _ / / 16 " -- r — — 14" -- 12" i _ _ _ — --. f- i — — 10" ..7 —_ / Si r . ,, - -- - - -- SCALE r- 6 �` 1 "_ 9000' "-- - - • . • • r r r - — • r • • f 1 7 1 "ter 1 / , I %. ......... _ ' .. / ' 1 1 `♦ FIGURE S. NOAA ATLAS 2. 24 -HOUR i_SC'F -4VI -A c concentration, the OCEMA methodology is also used for comparison purposes. In each methodology, all hydrology data is consistent; the only differences in approach is in the model- specified critical storm patterns. Additionally, no retardation of flows in the watershed is considered. All flows are assumed to concentrate at selected points according to the time distribution of the assumed watershed "S" curve. (6) Evaluate Model Results. A comparison of peak flow rates predicted by the several modeling approaches is given in the next section of this report. From the various results, the SBCFC methodology was found to predict lower peak runoff rates (for the specified parameters) that the RCFCD methodology. The identification of key factors which contribute to these differences are discussed in the following section. 0 U 0) 0 z z 0 0) 2 80278.40 - 6 -242 4 3 III. DISCUSSION OF RESULTS PEAK FLOW RATES Listed in Table I are the unit - hydrograph predicted peak flow rates for each watershed point of concentration. The unit - hydrograph parametric data used for each point of concentration is given in Table II. CRITICAL STORM PATTERNS: COMPARISONS From Table I, each methodology differed in estimated peak runoff values at each watershed point of concentration. Since each methodology used is based on identical parametric data and hydrograph theory (United States Corps of Engineers), the only difference lies in the modeled critical storm pattern; that is, the distribution and identification of peak rainfall intensities which are determined in the critical storm patterns differ between county methodologies. The major differences between the various considered county critical storm patterns can be summarized as follows: (1) OCEMA The OCEMA 3 -hour critical storm pattern is based on an actual rainfall event. The OCEMA uses county recorded and State of California rainfall gauge information as a data base to determine 3 -hour duration 100 -year storm rainfall. Based on the 3 -hour mass rainfall, simple proportions of the total rainfall are assigned to the various rainfall unit - intervals. The OCEMA method adjusts the peak 15- minutes, 30- minutes, 1 -hour, and total 3 -hours of rainfall due to Corps of Engineers determined depth area relationships (Figure 6). The peak rainfall events occur in a single nested sequence. Examination of the resulting rainfall intensities determined by the storm pattern indicates that extremely high short - duration rainfall intensities are defined (usually in excess of a 200 -year event for the 100 -year storm) for watersheds less than about five square miles in extent, and located in the coastal areas. For inland areas such as San Bernardino County, the peak rainfall intensities more closely match the recorded information than in Orange County. (2) RCFCD ° The RCFCD specifies a 3 -hour as well as a 6 -hour critical N storm pattern. Based on the earlier Day Creek study (1981), 0 the 6 -hour storm was considered more critical. The higher flow rates predicted by the 6 -hour storm may be explained by the 0 2 80278.40 - 6 -2 -82 5 J >J_ TABLE I. UNIT HYDROGRAPH PEAK FLOWRATE ESTIMATES (CFS) Day Creek Watershed Location 6 -Hr. Storm 24 -Hr. Storm Local 3 -Hr. Storm Point Q100 Q100 Q100 Number (RCFCD) (SBCFCD) (OCEMA) 1 6265 5310 7613 2 7384 6214 -- 3 9052 7375 8506 4 9849 8156 8957 6 11059 9260 -- 8 11394 9718 9623 San Sevaine Channel Watershed Location 6 -Hr. Storm 24 -Hr. Storm Local 3 -Hr. Storm Point Q100 Q100 Q100 Number (RCFCD) (SBCFCD) (OCEMA) 1 2184 1967 3089 2 3674 3077 -- 3 5991 5287 6960 4 8359 7115 - 4' 14048 11971 13486 5 19455 16201 -- 7 23572 20470 -- 8 21459 18395 -- 9 25087 20269 19066 11 27208 23120 -- 12 27285 22502 19218 0 0 0 Z Q Z 0 0) 2 Q 80278.40 - 6 -2 -82 6 � TABLE II. HYDROLOGY MODEL WATERSHED PARAMETERS Day Creek Reach L Lca AEL S Percent No. (ft) (ft) (ft) Ti (Acres) (in /hr) Mtn. 1 21500 11000 6139 0.050 3042 0.500 100 2 38000 19000 7379 0.046 5080 0.466 85 3 51500 26000 7699 0.039 7655 0.401 56 4 63000 31500 7859 0.036 9729 0.374 44 5 11446 6 72000 36000 7979 0.034 12753 0.352 34 7 13207 8 76000 38000 8019 0.033 13782 0.345 31 San Sevaine - Upper Etiwanda Creek Reach L Lca 6EL ZA S Percent No. (ft) (ft) (ft) n (Acres) (in /hr) Mtn. 1 15500 8200 3540 0.050 1273 0.500 100 2 17500 9.500 4161 0.050 1953 0.500 100 3 26500 12000 4761 0.042 3890 0.430 69 4 30500 16500 4120 0.041 6894 0.421 65 4' 31600 12500 4941 0.042 10784 0.430 67 5 34100 11500 4991 0.037 14728 0.385 49 6 16422 7 37100 11400 5041 0.035 18854 0.360 39 8 43100 17200 5126 0.035 19355 0.360 38 9 48300 20200 5201 0.033 24515 0.343 30 10 25367 11 57300 25200 5321 0.031 30788 0.329 24 12 75300 38800 5541 0.030 38590 0.318 19 U 0 Z Z 0 2 Q 80278.40 - 6 -2 -82 7 3 �. r uh u tlm i Yi" w . . 1 1a ui - ". ...sso..mt . ....0 unt - -: n s .... wtn a ks .. _ 1i=,,.- _n+nr..sso ..mon.nau. _.mnn� __ ___� - u.. . ..luntnrntl� nt Iun _ _ 3.0 ww........e. 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' _ u unnn m un i niiinll 1 11m hhhh i ii i1 m 11 uimu lu,nu i uwu a ∎o , . musimi Iunnl W ' l p I U1 I1U1 1IU11blll �p i�l�upp�1WNp...i UNIIIIMIII W1111 �I�n� uIuhl1 II� *V T�� �WY1 �I1 MIUMMumum1M ® ®vL ll II�II I II1ul W" 1 .I 2 4 6 8 10 20 40 60 80 100 150 I DRAINAGE AREA IN SQUARE MILES HYETOGRAPH COMPUTATION UNIT PERIOD Amount • 1 .07 (R(180)- R(60)) 2 .05 (R(180)- R(60)) 3 .11 (R(180)- R(60)) 4 .05 (R('180)- R(60)) 5 .20 (R(180)- R(60)) 6 .22 (R(180)- R(60)) 7 .14 (R(180)- R(60)) 8 .16 (R(180)- R(60)) 9 .48 (R(60)- R(30)) 10 .52 (R(60) R(30)) • 11 1.00 (R(15)) 12 1.00 (R(30)- R(15)) UNIT PERIOD .. 15 MINUTES LOCAL PROJECT STORM DEPTH-AREA DURATION CURVES ORANGE COUNTY FLOOD CONTROL DISTRICT C- 12 HYDROLOGY MANUAL PV'_I fl F A_ flCFMA 3 -HOUR CRITICAL STORM PATTERN RAINFALL RELATIONS misapportionment of peak rainfall intensities. The RCFCD uses the NOAA Atlas 2 for its rainfall data base. The county also uses an actual storm event to define its critical storm patterns. For the 6 -hour storm, the total mean rainfall is determined from the Atlas and adjusted according to the Atlas depth -area curves (Figure 7). Then, unit - intervals of rainfall are calculated as simple percentages of the adjusted 6 -hour mass rainfall. It can be noted that the RCFCD 3 -hour storm pattern is reduced by the depth -area curves more than the peak 3 -hour portion of the RCFCD 6 -hour storm pattern. Therefore, in the RCFCD methodology, interior 6 -hour storm peak intensities may exceed recorded rainfall values as adjusted by the depth -area curves, resulting in high estimates of runoff. However, for small watersheds (less than approximately two square miles) where depth -area adjustments are negligible, the RCFCD storm pattern is seen to determine rainfall intensities that are much lower than actual peak rainfall intensities. (3) SBCFC The new SBCFC methodology uses the NOAA Atlas 2 rainfall data base identical to the RCFCD. The assumed critical 24- hour storm pattern includes a single peak event similar to the OCEMA and RCFCD methods. However, the new SBCFC method adjusts the peak 1 -hour, 3 -hour, 6 -hour, and 24 -hour mass rainfall values according to the NOAA Atlas 2 depth -area curves (Figure 7) whereas the RCFCD only adjusts the total storm rainfall. Consequently the SBCFC method develops a critical storm pattern with rainfall intensities that closely approximates recorded rainfall data given by the Atlas. Table III summarizes the major similarities and dissimilarities between the various critical storm patterns considered. CRITICAL STORM PATTERNS: AS A FUNCTION OF WATERSHED AREA Each of the three considered unit- hydrograph methodologies are essentially identical models except for the assumed critical storm patterns specified for hydrologic study purposes. Consequently as discussed above, the sensitivity of modeling results focuses to the single variable: the critical storm pattern. Coupled to this variable is the sophistication involved by use of the depth -area curves. For example, examination of the OCEMA 3 -hour ° storm pattern (Figure 6) which implicity contains the depth -area curves indicates a considerable variation from the NOAA Atlas 2 depth -area curves 0 (Figure 7). However for small watersheds, the depth -area adjustments v cn introduce a negligible factor. z z 0 2 80278.40 - 6 -2 -82 8 3 0 0 0 m ~ UC.C..........C. m.. ...... %. %...... %mu ��������� \% .. ..0 UR*% U. UU. 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W ii EME ESSESE E NNEME N ENSI E M ' iii =i ■■■■■■■ 1°■■■ fI ■i1■iii�l/iEMENiiii °11 % %iif■MEME EM MUSEUM EM on O■■■■11■1 .... ■.u1/iMMINMENSEV 11MSMn..%..M %S/SSSMIL11■■i //■■11~11 1S■S...U.iiiriiiiiiaa..MEMEMES MMENEMENNUEMENEMENiii ° ■■ 11■■■■ 11■■ �11■■ r,■■/ ■■11■/1111■r■/■/111111■ ■//�a11//111111//11 g °- ■ /■■■ ■■MMEW/■■/► ■■ ■■■11■■■■11►I■■■■■■■UM■■N■■■■■/11 ■11■■ / /Iii� iiiniiiiiiiiiii iiiiiitiiii EINEENE A ■■■ttE ■ ■t ■ ■E'� ■// ■11//1111 ■ ■ ■ ■ ■t ■ //� /1111 ■t11 ■! ■ ■ /� / ■ttU■ ■■ ■ SEMEME■ EMMEW %■MEMMEM %MP %NNEE ■S7N11�►�ENNEEN • • •SEEM % R...1 E% U•%•. MMMENEMOM % %MM%% /EMEUNEMENOMEV711EEM\N 1111■ ■■ ■ ■ // I/■■ 11■■■■/n/ ■11■■/./■■ /7//t■1111t11m1/ /■ / //■/ .... . u mu faM a*• / m o ■ ■■ rM/ U■ nU■■■■■■■ O.■ ■// ► .a■t Ca■■/11/t11.■■■■11/11//■11/■ iiivi vi■iiiiMMi4MMM, Mumi■iiiciii mmum mu mmilimmiumeammommummumm erammummummummom ■., /Uv / ■11 /M/■ ■M11 /CS//EESI//11 ■■1111■■■■■ /ttt■■t■ ■11111 EN ■ nnium ws tmeammomm sm11■tt■■■■■■■■■ommummumm 11■■t er, o► aal! s s:ale:/gl■11■■■■■■■ ■11■■■ ■■■n/ ■/11// ■■11/11 ■11 1111// r i-. ct ■■■■11//■ ■1111■1111■/11/11110■///1111■1111 mmumm ■■ o0 °° 0 0 0 to 0 PERCENT OF POINT RAINFALL Reference: Bibliography items No.27 8 29. R C F C 5 W C C DEPTH- AREA - DURATION HYDROLOGY MANUAL RELATIONSHIPS FIGURE 7. NOAA ATLAS 2 DEPTH—AREA CURVES PLATE E-5.8 TABLE III. THREE - COUNTY CRITICAL STORM PATTERN COMPARISONS SUBJECT SBCFC RCFCD OCEMA Actual Storm Event? No Yes Yes Single Peak Storm? Yes Yes Yes Nested Peak Intensities? Yes Yes Yes Total Storm depth -area Adjustment? Yes Yes Yes Interior Storm depth -area Adjustment? Yes No Yes Depth -area Curves? NOAA NOAA CE Rainfall Data Base? NOAA NOAA OCEMA Hydrograph Procedure from U.S. Corps of Engineers? Yes Yes Yes Do Peak Rainfall Intensities Match Recorded Data for Small Watersheds (No depth -area Adjustment)? Yes High Low 1 NOAA Atlas 2 0 2 U.S. Corps of Engineers; OCEMA Hydrology Manual co 0 O co 2 80278.40 - 6 -2 -82 9 To demonstrate the critical storm pattern differences, each of the patterns were determined for specific rainfall values which occurred in the study watershed; namely, from the NOAA Atlas 2: Peak 1 -hour = 1.5 inches Peak 3 -hour = 2.9 inches Peak 6 -hour = 4.3 inches Peak 24 -hour = 9.8 inches The OCEMA storm uses the 3 -hour data; the RCFCD uses the 6 -hour data; and the SBCFC uses all four data values. The critical storm patterns were determined for three watershed areas: 1, 25, and 60 square miles. The critical storm patterns for each county and for each considered watershed area are shown in Figures (8), (9), and (10). From the figures, the RCFCD storm pattern produces low storm rainfall intensities for smaller watersheds, yet produces high rainfall intensities for large watershed areas. The OCEMA and SBCFC patterns, however, modify peak rainfall intensities in accordance with their respective depth -area relations. Comparison of the OCEMA and new SBCFC critical storm patterns indicates that the OCEMA depth -area adjustments are more significant than those used by the SBCFC method. This difference reflects a variation between the Corps of Engineers curves (used in the OCEMA method) and NOAA Atlas 2 curves (used in the SBCFC and RCFCD methods). The OCEMA storm pattern, although modified for internal peak intensities by depth -area relationships, is inaccurrate in the apportionment of the total mass rainfall to the peak 1 -hour, 30- minutes, and 15- minute durations. The SBCFC method, however, incorporates the recorded 1 -hour intensity log -log slope as determined by the Rational Method rainfall intensity plot. The differences in rainfall distribution are given in the tabulations of Tables IV, V, and VI. To better visualize a relationship between the various methodologies and predicted flowrates, a plot of mass - rainfall -ratio as a function of peak - flowrate -ratio is given in Figure (11). The SBCFC method and NOAA Atlas 2 data base is used as the denominator variable, with OCEMA and RCFCD method peak flowrates used as the comparison variable. o From Figure (11), the OCEMA methodology correlates strongly to the v SBCFC methodology with respect to peak one -half hour rainfall values. The cn RCFCD methodology, however, lumps with respect to both one -half hour and Z one -hour rainfall durations. z 0 2 J J 80278.40 - 6 -2 -82 10 3 A 45- A I 1 1 40- I 1 1 I 1 I I I 35- I I I - -- 1 SQUARE MILE WATERSHED 1 I 30- 25 SQUARE MILE WATERSHED 1 I 60 SQUARE MILE WATERSHED I I I I .. 1 I z 25- \ I I `� I� \ I 0 i I j20- I 1 I Z I � I I I J i J Q 15- J I I \ \ .... I Z 10- I i I Ni ,....--... i \ ./ I 5- ,1 1 . i f'---/-"-'\ ) r‘ - \./ 0 / � I � i 1 1 1 1 low 0 25 50 75 100 125 150 175 TIME ( MINUTES) Cie' r III a 9 .,e - PLIA (QTTt(A1 STClRM PATTERN AS A FUNCTION OF WATERSHED AREA 30 25 - - -- 1 SQUARE MILE WATERSHED A l fi •— 25 SQUARE MILE WATERSHED // � I 20 60 j MILE WATERSHED //I L ' �• I H id 15 ✓ // I z I _ / � J 10 / a , �� • R /. _---"' i X ." .. / .°.°. 5 % 0 • 0 25 50 75 100 125 150 175 TIME (MINUTES) FIGURE 9. RCFCD CRITICAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA 50-- 45-- �I - ---- 1 SQUARE MILE WATERSHED J I -•-- 25 SQUARE MILE WATERSHED I 40- 60 SQUARE MILE WATERSHED 35- ! I I; I 111, 30- I I •I 11 Y 3 I 25- J -J � � I 15- 10- \\\\ -\ ✓�� \'✓ 5 • -� 0 0 25 50 75 100 125 150 175 TIME (MINUTES) FIGURE 10: • SBCFC CRTTTCAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA TABLE IV. RAINFALL DATA AND DEPTH -AREA FACTORS Day Creek NOAA NOAA NOAA Atlas 2 Atlas 2 Atlas 2 Recorded Recorded Recorded Peak Peak Peak NOAA NOAA Waterhsed 1 -Hr. Mean 3 -Hr. Mean 6 -Hr. Mean Depth- Depth - Location Point Point Point Watershed Area Area Point Rainfall Rainfall Rainfall Area Factor Factor Number (in.) (in.) (in.) (mi (1 -hr) (6 -hr) 1 2.3 4.9 7.8 4.75 .97 .987 2 2.1 4.3 6.8 7.94 .95 .98 3 1.8 3.7 5.9 11.96 .93 .976 4 1.7 3.5 5.4 15.20 .91 .97 6 1.6 3.2 4.9 19.93 .895 .962 8 1.6 3.1 4.8 21.53 .888 .96 San Sevaine Channel NOAA NOAA NOAA Atlas 2 Atlas 2 Atlas 2 Recorded Recorded Recorded Peak Peak Peak NOAA NOAA Waterhsed 1 -Hr. Mean 3 -Hr. Mean 6 -Hr. Mean Depth- Depth - Location Point Point Point Watershed Area Area Point Rainfall Rainfall Rainfall Area Factor Factor Number (in.) (in.) (in.) (mi (1 -hr) (6 -hr) 1 1.9 4.0 6.3 1.99 .985 .995 2 2.0 4.3 7.0 3.05 .975 .992 3 1.9 3.8 6.0 6.08 .96 .985 4 1.7 3.5 5.4 10.77 .935 .978 4' 1.8 3.6 5.6 16.85 .91 .968 a 5 1.7 3.4 5.3 23.01 .88 .958 7 1.7 3.3 5.0 29.46 .855 .95 = U 8 1.7 3.3 5.0 30.24 .852 .948 ` 9 1.6 3.1 4.8 38.30 .825 .94 a 11 1.6 3.0 4.5 45.11 .803 .93 a 12 1.5 2.9 4.3 60.30 .78 .918 p rn 2 a 80278.40 - 6 -2 -82 11 3 TABLE V. PEAK MODELED 1 -HOUR RAINFALL Day Creek RCFCD SBCFCD OCEMA Watershed Adjusted Adjusted Adjusted Location Peak 1 hr. Peak 1 hr. Peak 1 hr. Point Mean Mean Mean Number Rainfall Rainfall Rainfall 1 3.04 2.23 3.44 2 2.63 2.00 2.80 3 2.27 1.67 2.22 4 2.07 1.55 1.98 6 1.86 1.43 1.70 8 1.82 1.42 1.62 San Sevaine Channel RCFCD SBCFCD OCEMA Watershed Adjusted Adjusted Adjusted Location Peak 1 hr. Peak 1 hr. Peak 1 hr. Point Mean Mean Mean Number Rainfall Rainfall Rainfall 1 2.48 1.87 3.15 2 2.74 1.95 3.23 3 2.33 1.82 2.59 4 2.09 1.59 2.12 4' 2.14 1.64 1.99 5 2.01 1.50 1.74 7 1.88 1.45 1.59 8 1.87 1.45 1.58 9 1.78 1.32 1.39 11 1.65 1.28 1.26 12 1.56 1.17 1.14 a 1 0 0 Z Q Z 0 cn 2 Q D 80278.40 - 6 -2 -82 12 TABLE VI. PEAK MODELED 1/2 -HOUR RAINFALL Day Creek RCFCD SBCFCD OCEMA Watershed Adjusted Adjusted Adjusted Location Peak 1/2 hr. Peak 1/2 hr. Peak 1/2 hr. Point Mean Mean Mean Number Rainfall Rainfall Rainfall 1 2.07 1.61 2.41 2 1.79 1.44 1.94 3 1.54 1.22 1.54 4 1.41 1.13 1.37 6 1.26 1.04 1.15 8 1.24 1.03 1.10 San Sevaine Channel RCFCD SBCFCD OCEMA Watershed Adjusted Adjusted Adjusted Location Peak 1/2 hr. Peak 1/2 hr. Peak 1/2 hr. Point Mean Mean Mean Number Rainfall Rainfall Rainfall 1 1.69 1.36 2.17 2 1.86 1.42 2.22 3 1.58 1.33 1.78 4 1.42 1.16 1.48 4' 1.46 1.20 1.36 5 1.37 1.09 1.16 7 1.28 1.06 1.05 8 1.27 1.06 1.04 9 1.21 0.96 0.91 11 1.12 0.93 0.81 a 12 1.06 0.85 0.72 z 0 u) Q z a z 0 2 a J 80278.40 - 6 -2 -82 13 3 1.7– o O 1.5– ,s 0 \;-‘ 0 1.3– � o O G A O U Q , • • * U 1.1 ° '21a. o a o a 0 0 o 09– C� o 0.7– 05 0.5 0.7 0.9 1.1 1.3 1.5 1.7 (CRITICAL PEAK RAINFA L I S'g' RAN ALL 1 — O.C.E.M.A. METHOD, PEAK 30-MINUTES -- R. C.F C.D. METHOD, PEAK 30 - MINUTES O -- O.C.E.M.A. METHOD, PEAK 60- MINUTES *— R.C.F. C.D. METHOD, PEAK 60- MINUTES FIGURE 11. PEAK RAINFALL AND PEAK RUNOFF CORRELATION TO SBCFC VALUES IV. REFERENCES Orange County Environmental Management Agnecy, 1978. Hydrology Manual. Riverside County Flood Control and Water Conservation District, 1978. Hydrology Manaual. San Bernardino Flood Control, 1982. Hydrology Manual. NOAA Altas 2, Volume XI - California, U.S. Department of Commerce, 1973. Progress Report on Day Creek /San Sevine Channel: Hydrology Study, Williamson and Schmid, 1982. U 0 Z Z 0 2 80278.40 - 6 -2 -82 14 ‘4AsiO" ! ■ t , • 1 ' 0 .- ▪ - I , I \ i l • • 1 1 r -, , --' - -- -- ---11 ec,,eleD 0 • ; 1 i I, :,, • : 0 • • II 11 1 i (7-if: , ' — i < Is * • 2 tjji 7 . a w ,.--_ . '_ ,,,, arirwancraaa 1..ii _1 .,Ei,),,,i : 1-- ` - .1 i 1, I .9t. , .9i. . - d k , , 1111111 . . ›.. to rip i I! • . 1 ', li - 21111 ..- _. : V ' ‘ • U: U. . I. ' A 4, * Li 0 ,..., 0 s 1 . r L7 CC „ a ..;—. J ,1 .. • ,...' i .9C • ' — . a 7 • 1 11 9 < .99 • ..: CO Z a 0 > 0 ...... - -±' , II H3338 H0338 a < . 4._ .„...1 .7 t.". c:) 1 ..— . . . . . . ... IS 9 '' ' ' .. 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