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HomeMy WebLinkAboutFlood Control Facilities West EndId 11r Sri I� REVISED SUPPLEMENTAL REPORT FLOOD CONTROL FACILITIES BD FONTANA WEST END VENTURE CITY OF FONTANA January, 1986 Prepared by Bill Mann & Associates 1814 Commercenter West Suite A San Bernardino, CA 92408 1 TABLE OF CONTENTS P age SECTION 1. INTRODUCTION AND PURPOSE OF REVISED 1 SUPPLEMENTAL REPORT "NA 1.1 PROJECT LOCATION 1 1 1.2 PURPOSE OF REVISED REPORT SECTION 2. REVIEW OF POTENTIAL INCREASED RUNOFF FROM 4 PROJECT DEVELOPMENT 2.1 GENERAL 4 ri 2.2 ESTIMATED INCREASED POST - DEVELOPMENT 5 DRAINAGE FLOWS FROM SITE d SECTION 3. ELIMINATION OF FLOODING ALONG BANANA STREET 7 lw 3.1 GENERAL 7 SECTION 4. REVISED FLOOD CONTROL FACILITIES PLAN 8 4.1 GENERAL 8 4.2 REVISED FLOOD CONTROL FACILITIES PLAN 8 4.3 FLOOD CONTROL PLAN SUMMARY 10 4.4 RUNOFF FROM SITE WEST OF EXISTING 12 ETIWANDA CHANNEL 1 do 1 iw IK SECTION 1. INTRODUCTION AND PURPOSE OF REVISED SUPPLEMENTAL REPORT 1.1 Project Location A Specific Plan has been prepared for the approximate 1,500 acres located north of Foothill Boulevard and east of East Avenue in the City of Fontana. The Specific Plan was approved by the City of Fontana on April, 1985. The Specific Plan area is shown on Figure No. 1. '* The project area is traversed by two major unimproved flood channels. The Etiwanda Creek Channel traverses the westerly part of the site and the San Sevaine Creek Channel traverses the approximate middle of the site. The j existing San Sevaine Creek Channel is due to be removed and combined with the y existing Etiwanda Channel, thus elimir.ating the channelization of San Sevaine Creek flows through the middle of the site. a'" Due to the proposed elimination of the existing San Sevaine Creek Channel, certain flood control facilities are necessary north and south of the project nRe area in addition to onsite channelization. The existing flood control facilities and the proposed offsite flood control facilities are shown schematically on Figure No. 1. 1.2 Purpose of Revised Report The purpose of this revised report is to update the planned flood control facilities proposed for the subject development. As indicated above, the BD Fontana West End Venture project area is traversed by the Etiwanda and San Sevaine Creek Channels. At the time the project area Specific Plan was prepared, a "Flood Control Facilities Study" and a "Supple- mental Report" with recommendations for the control of flood flows and drainage were provided. The two reports and recommendations were based on, 6 and are in conformance with the Day, Etiwanda and San Sevaine Creeks System y y Drainage Plan prepared in March, 1983. The two studies are listed below for reference. West End Specific Plan, Flood Control Facilities Study, September, 1984 West End Specific Plan, Flood Control Facility Alternatives, ON Supplemental Report, November, 1984 rd .s These studies and the plan of action for flood and drainage control were it approved by the San Bernardino County Flood Control District and City of Fontana. The Flood Control District approval letter and recommendations are am included in the Appendix for ready reference. 9 Two alternative flood control plans were presented in the above referenced "Supplemental Report ". Alternate B was recommended and approved by the Flood Control District and City of Fontana. A summary of the approved plan (Alternate B) is also included in the Appendix for ready reference. on This report does not completely replace the two above mentioned reports. This report does revise the recommended Flood Control Facilities Plan as described in Section 4. The only major changes are in the proposed excavation for storm flow detention north and south of the site. The hydrology for the San Sevaine Creek Watershed is being updated and will be ..� submitted by a separate report. B 3 SECTION 2. REVIEW OF POT ENTIAL INCREASED RUNOFF FROM PROJECT DEVELOPMENT 2.1 General The recently developed San Bernardino County Detention Basin Policy states, " I" ... the post - development peak flow rate generated by the site shall be less di than or equal to 90% of the Ao�t development peak flow rate from the site for all frequency storms up to and including the 100 -year frequency storm ... Only 2, 10, 25 and 100 -year storm need to be analyzed." .y When the "West End Specific Plan, Flood Control Facilities Study" was prepared w in September, 1984, it was recommended that the increase in the development dw generated drainage runoff from the site be provided for by a combination of providing onsite and offsite drainage detention capacity. Small storm flows am (2 - year to approximately 5 - year frequency storms) were to be handled y "onsite" detention facilities, with larger storm flows (increase) to be pro- '""' vided for by improving "offsite" storm flow detention capacity. This concept was accepted by the Flood Control District and City of Fontana. ww The following improvements of offsite drainage detention facilities were proposed: �I a. Turnout from existing Etiwa Channel into Victoria Basin. b. Excavation of 200,000 yd3 from the proposed Lower San Sevaine Basin "1 (124 acre -feet) Approximately 55+ acres (250 acre -feet) of onsite drainage retention facili- ties were proposed to handle the residual increased development flows at a cost of approximately $600,000. However, it has always been the contention of the developer and the engineers that the funds that would be placed in temporary onsite detention facilities 0 fl could best serve the regional drainage and flood control system and the general area as a whole by being applied to permanent facilities. Therefore, it is recommended and the intent of this revised plan to place the funds into the regional system, such as the expansion of the Lower San Sevaine Basin, Hickory Basin and /or Jurupa Basin to compensate for increased drainage flows from the development. Local, temporary storm flow detention basins are as expensive to remove as the facilities are to construct initially. There are many cases in the valley area where storm flow detention cannot be accomplished in permanent regional facilities due to the location of the development away from regional channels and /or basins. However, the West End Venture development is in close proximity to existing and proposed storm flow detention basins. 9 dW di dW w �I 0 2.2 Estimated Increased Post - Development Drainag Flows from S ite The increase in drainage flows from the site has been calculated by analyzing the present site conditions and future development. The increase in flows are summarized in Table I. Table I Present Future Condition Condition Increased Runoff (ac -ft) Area (ac -ft) (ac -ft) 2 =yr 10 -yr 25 -yr 100 -yr West End 126 (2 yr) 263 (2 yr) 137 Venture 290 (10 yr) 521 (10 yr) 231 Development 383 (25 yr). 647 (25 yr) 264 574 ( 100 yr) 893 ( 100 yr) 319 5 F The increased runoff volume to be generated by the site upon full development �*+ is approximately 320 acre -feet for a 100 -year storm. This is an increase of IM approximately 56% over the runoff in the natural condition. It should be noted this increase will be over a number of years and will not occur immediately. It is intended to provide for the increase in site runoff volume by assisting in the development of offsite detention facilities in excess of the estimated increased runoff volume of 320 acre -feet. a/ It is also emphasized that the construction of the proposed channel south of *A Foothill Boulevard will eliminate the major flood flows that outlet onto rrY Banana Street and floods the area along the street during even minor floods. Therefore, the project flood .control facilities will not only provide for increased site generated flows, but will also, remove storm flows from Banana do Street that are generated offsite north of this site and presently pass OM through the site. 40 an aw OR va ri i DI �kl 6 D e a SECTION 3. ELIMINATION OF FLOODING BANANA STREET 3.1 General , The San Sevaine Channel presently outlets onto Banana Street at Foothill Boulevard. Due to the limited water - carrying capacity of Banana Street, even small storms cause flooding along the street. Major storm flows on the street in 1978 caused overflow and damage to homes along the street. ar "" The Flood Control Facilities Plan calls for the relocation of the existing San do Sevaine Channel to the existing Etiwanda Channel alignment. The new channel 04 will be designed for the combined Etiwanda and San Sevaine Creek flows. Refer „ to Figure No. 1 for the proposed ultimate channel construction between the Devore Freeway and Foothill Boulevard and the proposed interim channel south 4W of Foothill Boulevard. The new San Sevaine Channel will effectively remove flood flows from Banana Street. The elimination of the Banana Street flooding problem is emphasized in this ®. report because the removal of the downstream flooding due to offsite flows has V1 a much greater benefit to the do; istream area than the elimination of increased flows from the development. The proposed Flood Control Facilities Plan for the project will eliminate the Banana Street flood problem and Ai provide for increased drainage flows generated by the project. The proposed Flood Control Facilities Plan is discussed in Section 4. E e E] N 7 i F SECTION 4. REVISED FLOOD C ONTROL FACILITIES PLAN 4.1 General It is proposed to increase the drainage detention capability in the offsite Ali basins to compensate for the increased drainage flows that will be generated by the site as it develops. The proposed drainage detention capability will be developed in the Lower San Sevaine Basin, Hickory Basin and possibly Jurupa Basin. Refer to Figure No. 1 for the location of the BD Fontana West End Venture project site and the proposed onsite and offsite flood control and drainage detention facilities. The revised Flood Control Facilities Plan is discussed in Section 4.2. 4.2 Revised Flood Control Facilities Plan The "Flood Control Facilities Plan" for the BD Fontana West End Venture generally includes the construction of the ultimate San Sevaine Channel It is not proposed to make any major changes in the approved "Flood Control "interim" channel between Facilities Plan" presented in the "Flood Control Facilities Alternatives, Supplemental Report ", dated November, 1984. The approved plan (Alternate B) storage, and partial excavation is included in the Appendix of this report for ready reference. The above referenced report should be reviewed for a detailed analysis of the regional flood problems in the general area. detention, if necessary. It is proposed to increase the drainage detention capability in the offsite Ali basins to compensate for the increased drainage flows that will be generated by the site as it develops. The proposed drainage detention capability will be developed in the Lower San Sevaine Basin, Hickory Basin and possibly Jurupa Basin. Refer to Figure No. 1 for the location of the BD Fontana West End Venture project site and the proposed onsite and offsite flood control and drainage detention facilities. The revised Flood Control Facilities Plan is discussed in Section 4.2. 4.2 Revised Flood Control Facilities Plan The "Flood Control Facilities Plan" for the BD Fontana West End Venture generally includes the construction of the ultimate San Sevaine Channel F � 8 between the Devore Freeway and Foothill Boulevard, construction of an "interim" channel between Foothill Boulevard and the Santa Fe Railroad to the south, the excavation of 200,000 yd3 in Lower San Sevaine Basin for debris storage, and partial excavation of Lower San Sevaine Basin and Hickory Basin for storm flow detention. Partial excavation in Jurupa Basin will be provided for additional storm flow detention, if necessary. F � 8 The revised plan does not include any proposed changes to the basic flood control channel improvements recommended in the "Supplemental Plan ". The recommended revisions include the design of and additional excavation in the proposed Lower San Sevaine Basin, the design of and partial excavation of Hickory Basin, and excavation in Jurupa Basin, if necessary. The proposed changes involve enhancement of storm flow detention to compensate for the increased runoff to be generated by site development. Under. the "revised plan ", the proposed excavation in Lower San Sevaine Basin has been increased from 200,000 yd to 400,000 yd (215 acre - feet). It is proposed to provide in excess of 140 acre -feet in Hickory Basin by construc- ting the basin embankment and spillway. Flows from San Sevaine Channel will be turned into the basin by a 36 -inch RCP. The proposed 400,000 yd excava- tion in Lower San Sevaine Basin is in addition to the proposed 200,000 yd excavation included in the original plan for debris control. The estimated increase in runoff volume due to the proposed development is 320 acre -feet based on a 100 -year design storm. The proposed detention volume to be provided in the Lower San Sevaine Basin and Hickory Basin is 355 acre -feet or 111% of the projected increase in runoff volume. The revised Flood Control Facilities Plan is summarized below. The estimated construction cost has been updated from the November, 1984 "Supplemental Report" using the ENR Index. The hydrology for the San Sevaine Creek Watershed is being updated and will be submitted by a separate report and is not included herein. As shown -in Table I, the increased runoff from the entire site for a 2 -year storm is estimated at 137 acre -feet. The construction of Hickory Basin with a turnout from San Sevaine Channel will compensate for the increased runoff from small storms. H J E 9 4.3 Flood Control Plan Summary +� The revised "Flood Control Facilities Plan" generally includes the construc- tion of the ultimate San Sevaine Channel between the Devore Freeway and Foothill Boulevard, construction of an "interim" channel between Foothill Boulevard and the Santa Fe Railroad to the south, the excavation for some ww debris and storm flow capacity in the proposed Lower San Sevaine Basin, dd excavation within the proposed Hickory Basin, and partial excavation in Jurupa Basin, if necessary. u/ *� Refer to Figure No. 1 for a schematic location and description of the compo- nents of the plan. Specifically, the features and estimated cost of the Flood Control Facilities Plan are as follows: s +rr a. Construction of the ultimate San Sevaine Channel (combined Etiwanda and San, Sevaine Creeks flow) from the Devore Freeway to Foothill Boulevard. Until the ultimate San Sevaine Channel is constructed ■. below Foothill Boulevard in accordance with the "Drainage Plan" and /or the Lower San Sevaine Basin is constructed, existing Etiwanda and San Sevaine Creek flows cannot be comingled. There - fore, a trapezoidal concrete channel is proposed with a separator wall separating the flows. Existing Etiwanda Creek flows would be directed to the existing RCB under Foothill Boulevard, and existing San Sevaine Creek flows would be directed to the proposed "interim" channel south of Foothill Boulevard. Estimated Cost = $5,435,000 b. Construction of an "interim" earth channel along the ultimate channel alignment from Foothill Boulevard southerly to connect to the existing San Sevaine Channel immediately south of the Santa Fe h q 10 M 9 0 IIRR Ai rrr w err r �.r .rr +q 4 1 4 4 dW Railroad. The construction would include the ultimate road crossing structures. estimated Cost = $2,000,000 C. Develop "offsite" drainage detention capability in the Lower San Sevaine Basin to partially compensate for necessary "onsite" retention of drainage flows. Excavation in the Lower San Sevaine Basin would approximate 400,000 yd3. The material will be placed in the basin levee. Estimated Cost = $ 600,000 d. Develop 200,000 yd3 of debris storage in Lower San Sevaine Basin to provide for major flood debris production on San Sevaine Creek. The material will be placed in the basin levee. Estimated Cost = $ 300,000 The combined excavation of 600,000 yd3 described in "c" and " d " above is equivalent to approximately 215 acre -feet of storm flow detention. e. Develop "offsite" drainage detention capability in Hickory Basin to compensate for necessary "onsite" detention of increased drainage flows from the site. Storm flow detention in excess of 140 acre -feet will be provided by constructing the basin levee, spillway and turnout. Estimated Cost = $ 300,000 SUBTOTAL = $ 8,735,000 0 Because of the area below the Devore Freeway tributary to the existing San Sevaine Channel, it will be necessary to construct a channel or storm drain from the existing San Sevaine Channel to the proposed concrete lined channel for purposes of conveying local drainage flows to the channel. The excavation of the Lower San Sevaine Basin does not provide for local drainage flows north and northeast of the site originating southeasterly of the Devore Freeway. R ol The storm drain or channel would be located along Baseline Avenue and is shown schematically on Figure No. I. Storm Drain Estimated Cost = $1,200,000 Estimated Flood Control Facilities Plan Cost =, $9,835,000 Because of the liabilities involved with comingling Etiwanda and San Sevaine Creek flows prior to an adequate concrete lined channel being constructed downstream of the project area, thesc flows must be kept separated. There- fore, a trapezoidal channel with a wall separating the flows is recommended. A schematic depiction of the channel is included herein as Figure No. 2. The dw final size and configuration of the channel cross - section will depend on final design of the channel system. OR 4.4 Runoff from Site West of Existing Etiwanda Channel The runoff values shown in Table I are for the entire site. The "revised" Flood Control Facilities Plan provides for the increased runoff from the entire site, as described in Subsections 4.2 and 4.3, by partial excavation of the proposed Lower San Sevaine Basin and the construction of Hickory Basin. However, due to the necessity of constructing parallel channels to separate Etiwanda and San Sevaine Creek flows, it is not possible to direct flows from the site west of the existing Etiwanda Channel to the interim channel to be constructed south of Foothil.1 Boulevard. M V YJ D +wi do w ri am do go ud Oft tai OR id w There are 166 acres of the proposed development west of the existing Etiwanda Channel. The 166 acres will generate 60 acre -feet of increased runoff based on a 100 -year storm. There are approximately 550 acres of the proposed development located between the existing Etiwanda Channel and the existing San Sevaine Channel. A portion of the approximate 550 acres historically drained to Etiwanda Channel, with the remainder draining southerly. The runoff from the 550 acres will be directed by storm drains to the San Sevaine Channel and then into Hickory Basin in accordance with the Day, Etiwanda and San Sevaine Creeks System Drainage Plan. The increased runoff from the development west of the existing Etiwanda Channel will be more than compensated for by the direction of drainage flows i east of the Etiwanda Channel to San Sevaine Creek and Hickory Basin. 13 U-11 IL - 1 IL-1 IL -1 IL-1 U. _j &i:i..i tai. CHANN R/W 100 - 105' SEPARATOR WALL A r -Morn &Inn SAKI SFVAINF VARIES 24' - 25' COMBINED CHANNEL ETIWANDA AND SAN SEVAINE CREEKS FLOWS NOTE - CHANNEL DIMENSIONS ARE PRELIMINARY. FINAL DIMENSIONS WILL DEPEND ON FINAL HYDRAU AND DE FIGURE N0.2 VARIES VARIES 9' -II' 13' -14' FLOOD CONTROL /AIRPORTS 825 East Third Street • San Bernardino, CA 92415 -0835 • (714) 383.1665 n City of Fontana P. 0. Box 518 Fontana, CA 92335 Attention: Mr. Bob Shoenborn Director of Public Works ENVIRONMENTAL PUBLIC WORKS AGENCY UN Ate. V, 11`N� MICHAEL G. WALKER �\!r Director January 7. 1985 File: 1- 701/1.00 1- 801/1.00 124.0209 Re: Zone 1, Etiwanda & San Sevaine Channel Systems West End Specific Plan Gentlemen: This office has completed review of the West End Specific Plan Flood Control Facilities Study plus Supplemental Report, proposed Etiwanda & San Sevaine Channel alignments, and detention basin proposals submitted by Bill Mann & Assocites for our review by letters dated October 2, 1984, October 16, 1984, October 30 , 1984, and November 13, 1984 (copies attached). The West End Specific Plan proposes an urban project to be located generally east of East Avenue, south of Baseline Road, west of Hemlock Avenue and north, of Foothill Boulevard in the northwest portion of the City of Fontana. The West End -Specific Plan Flood Control Facilities Study describes the existing. District facilities along the Etiwanda and San Sevaine Creek Systems. The West End Specific Plan also discusses the flood hazards to the site from these facilities. The plan should also address the possibility of the Etiwanda and San Sevaine Creek flows comingling upstream of the Devore Freeway and then the comingled flows entering either San Sevaine Channel or Etiwanda Channel, then traversing the site. The Supplemental Report discusses two alternatives for protecting the proposed development from San Sevaine and Etiwanda Creek flows. Both alternatives follow the "Day, Etiwanda and San Sevaine Creeks System Drainage Plan" with minor modifications.. B.ill Mann & Associates' letter dated October 16, 1984, proposes to increase the storage volume of San Sevaine Basin OS by substantially increasing the basin's levee height. 'Phis proposal pertains to -both alternatives mentioned above. Raising the din height may increase the District's maintenance costs by: 1. Having to remove all vegetation which might hide rodent holes ' in areas of possible piping — these: areas. are greatly increased when levee height is increased. Vegetation and grasses which would cover the levee or trees with deep root systems would not be acceptable. Certain shrubs with - I shallow root systems may' be acceptable. 1 JA 09 00 1 - ■ r Letter to the City of Fontana January 7, 1985 Page 2 2. Increasing the number of times a year inspection of the levee must occur. 3. Having to repair any erosion immediately after it occurs in order to guarantee the dams structural integrity and restore the required storage capacity. The District presently does not have the maintenance personnel to adequately accomplish the above. If maintenance does not occur the District may be responsible for any downstream damage resulting from the lack of adequate maintenance. It may be, by the time of construction, the District may have adequate personnel. An alternative may be the formation of a maintenance district. The increased height would make the basin more visible and may have environ— mental impacts. Since the proposed freeway southerly of the basin will be elevated above existing ground, the increased height may not be a problem. Both the original -and new proposals would have to go through the environmental process. It appears there may be more objection to the elevated levee. The District would not object to the proposal if the environmental concerns can be mitigated including the safety concern in storing water above surrounding natural ground level. It is generally felt the benefit from the increased storage volume will outweigh the increased maintenance costs and environmental concerns. Of the two alternatives proposed, Alternative "B" is recommended. This alternative would - involve the construction of a concrete trapezoidal channel with a separator wall for Etiwanda and San Sevaine Creeks between the Devore Freeway and Foothill Boulevard. Downstream of Foothill Boulevard, Etiwand a Creek flows would be returned to the existing historical flowpath while San Sevaine Creek flows would be conducted south in an interim earth graded channel to the Santa Fe Railroad where the flows are returned to the existing historical flowpath near Hickory Basin. In addition, San Sevaine Basin 05 and Victoria Basin would be upgraded to provide flood protection, water conservation, and flow attenuation. The District has easement for San Sevaine -Creek downstream of Hickory Basin through the old Kaiser Steel Plant. The District does not presently maintain this easement. This easement has been maintained by the property owner. The flowrate through this channel reach will not be increased, but the volume of .flow will be increased. The possible liabilities which may be incurred by the District and City from the increased volume of flow and the strength of the District easement will be reviewed by County Counsel to determine if the present fee owner must be consulted. ' Letter to the City of Fontana January 7, 1985 Page 3 t According to the ultimate,.onsite drainage plan, the local tributary flows to the site from the northeast would be intercepted by a storm drain in Adequate provisions shall be provided to protect the site from Baseline Road and conducted to the proposed San Sevaine Channel. Also, ' the flows generated onsite would be intercepted by storm drains within Channel. This the development and conducted to the proposed San - Sevaine A plan showing these provisions shall be provided and approved would help alleviate the existing flooding problems along Banana Street. Also, detention basins would be provided along with the expansion of existing ' District Basins to handle the incremental flows generated by the development The flow in Etiwanda Creek, San Sevaine Creek and Banana Street from all frequency storms. This may not cover all liabilities arising from development of subject site. According to the Supplemental Report ' these facilities would not be developed until Phase III. It appears Phase storm event. Due to the complexity of the downstream drainage I & Il can be adequately protected from San Sevaine - Etiwanda Creek over and tributary flows by a combination of structural walls, earth berms and ' water carrying streets, as discussed on page 27 of the Supplemental Report, along Banana hydrology and hydraulic calculations shall be provided and but this does not address the downstream drainage problems Street. our recommendations for Phase I are as follows: 1. Adequate provisions shall be provided to protect the site from ' San Sevaine Creek - Etiwanda Creek overflow and tributary flows. A plan showing these provisions shall be provided and approved prior to approval of Phase I. ' 2. The flow in Etiwanda Creek, San Sevaine Creek and Banana Street shall not be increased due to the development by any frequency storm event. Due to the complexity of the downstream drainage ' _proposed solution a preliminary plan plus adequate problems .and d approve hydrology and hydraulic calculations shall be provided and prior to approval of Phase I. The solution will necessitate improve- ment of San Sevaine Basin N5, Victoria Basin and onsi to detention ' to handle the increased flows generated by the development. Develop- ment of the District's Hickory Basin (downstream of the site) may also be necessary. ' 3. A plan plus the necessary hydrology and hydraulic calculations shall be provided prior to approval of Phase I showing there exists adequate developable storage volume in Victoria Basin and San Sevaine Basin n5 to be used by City of Rancho Cucamonga the County and the City of Fontana ' U. Preliminary basin development plans for San Sevaine Basin 05 and Victoria Basin plus the necessary hydrology and hydraulic calculations shall be provided prior to approval of Phase I showing Alternative ' 11 B is feasible. The calculations shall include: II II II n 0 Letter to the City of Fontana January 7, 1985 Page 4 (a) inflow hydrographs, (b) basin depth vs. capacity curves, (c) basin depth vs outflow curves., (d) outflow hydrographs, and (e)'sizing of Etiwanda and 'San Sevaine Channels (f) debris volume determination 5. Phase I, as proposed, represents approximately 1/3 of the entire developable area and no drainage facilities are scheduled in this phase except the expansion of San Sevaine Basin N5 and Victoria Basin to handle the inc. emental flows generated by this phase. This precedent is extremely dangerous as it creates development and increases runoff without providing the .proportionate share of the drainage system. Later sales could put subsequent owner(s) in a- position of responsibility for a disproportionate share of the system and the subsequent owner(s) could possibly receive relief from some of the costs at the expense of the San Bernardino. County Flood Control District and /or other entities. Therefore, , there needs to be guarantees in the West End Specific Plan that the necessary facilities are constructed at an equitable cost by existing and future owners. Development of the West End Specific Plan area shall be tied to the necessary regional flood control improvements. Our recommendations for Phase II are as follows: 1 1 1. Etiwanda Channel shall be improved to the ultimate concrete divided ' channel section from the Devore Freeway to East Avenue based on 4 Alternative "B" and calculations provided by recommendation for Phase I. San Sevaine flows shall not enter at this time unless ' the recommendations for Phase III are met. 2. The flow in San Sevaine Creek and Etiwanda Creek shall not be increased due to the development. An adequate plan and supporting calculations shall be pro -ided. 3. Some form of energy dissipation shall be provided where Etiwanda ' Creek Channel flows are returned to natural. 4. If it is deemed by the District that there is an adverse effect on the downstream property where Etiwanda Channel flows are returned be from - to natural, a flowage acceptance letter shall- obtained the property owner. If it can be shown there is no adverse effect ' on the downstream property the letter may not be necessary. 1 1 Letter to the City of Fontana January 7, 1985 ' Page 5 Our recommendations for Phase III are as follows: 1. 'San Sevaine Channel shall be improved to the ultimate* concrete- . %.!. channel l section from the Devore Freeway through •Foothi *ll -Boulevard, Y,� i based on Alternative "B" and calculations provided by-Recommendatiow. 4 for Phase I. Energy dissipation shall be -provided -where the. concrete channel ends. 2. An earth graded charnel shall be provided for San* Sevaine Creek from Foothill Boulevard to the old Kaiser Steel Plant property as described in Alternative "B ". All road and railroad crossings shall be improved to ultimate design. Bottom controls will be necessary if the flow velocities when calculated are determined to be excessively erosive and degradation of flowline profile.' can reasonably be expected. 3. If it is deemed by the District that there is an- adverse:. effect,%- - . - .,! . on the downstream property where the earth San Sevaine; Channel is returned to its existing flowpath a flowage :acceptance :; ' letter shall be obtained from the downstream property owner.. If it can be shown there is no adverse effect on the downstream... • . property, the letter may not be necessary. By taking. the• flows into Hickory Basin, then returning them to the natural- flowpath-.. %.••. the adverse effects on the downstream owner may be.m•itigated.. This possibility would require documentation and flood. routing -. : ' calculations to verify that peak flow rates are not increased.. : 4. San Sevaine Basin #5 shall be adequately excavated for flow attenuation ; -:•f . and debris retention per plan and calculations provided as.•part :r'�...- of Phase I. '5 . On site drainage facilities shall be provided to conduct the-tributary ' flows to Etiwanda and San Sevaine Channels. The City may want to require a portion of the system to be installed under Phases I and II. It appears this project will provide -lore than its fair share of improvements : : to the Etiwanda - San Sevaine Creeks System. For an equitable solution +. to the Etiwanda - San Sevaine Creeks drainage problems, the District, City ' , of Fontana and other affected cities should meet and consider: •forming a development advisory committee(s). The committee(s)•; should include major s,•. developers/owners in the Etiwanda and San Sevaine watershed. The goal of the committee(s) would be to form policy and guidelines, and determine ' what means of funding may be available to construct ultimate channel facilities : for Etiwanda and San Sevaine Creeks. A steering .committee and technical, ' committee similiar to that formulated for the development of the Day, Etiwanda and San Sevaine Creeks Drainage Plan and the Day Creek Water Project is recommended. As part of the development policy a reimbursement program 'r Letter to the City of Fontana January 7. 1985 Page 6 could be established for developers who provide facilities whose costs are greater than the developments fair share. This could be developed by the technical and steering committee(s). Should you have any further questions concerning this matter, please feel free to contact Allan J. Kielhold, Chief, rater Resources Division at (714) 383 - 2388. Very truly yours, CHARLES L. LAIRD Assistant Director Administration Flood Control CLL :RWC :mjs cc: City of Fontana, Attn: Terry Draper, Planning Director Attn: Reed Flory., Prog. Dir. (West End Spec. Plan) DB Investors, Inc. Attn: Joe Di Iorio City of Rancho Cucamonga, Attn: Lloyd Hubbs, City Engr. Attn: Jack Lam. Community Development Dir. City of Ontario Attn: Leroy Bender Riverside County FC & WCD Attn: Bob Nelson. Bill Mann Mike Walker bcc: —4tiben Montes Tony Gray Ken Miller Bill Collins Pete Mercado i L.LL .MANN & ASSOCIATES Civil Engineering • Drainage — Flood Control • Special Studies February 11, 1985 File: 84 -14 Mr. Charles L. Laird Assistant Director San Bernardino County Department of Transportation/ Flood Control /Airports 825 East Third Street San Bernardino, California 92415 Subject: West End Specific Plan - Etiwanda and San Sevaine Channel SyStem:s, Fontana Dear Chuck:. Reference is made to your letter dated January 7, 1985, in response to the "Flood Control Facilities Study, West End Specific Plan" and the-"Supple- ' mental Report, Flood Control Facility Alternatives, West End Specific Plan" prepared by Bill Mann & Associates. The reports were prepared for the West End Specific Plan located at Foothill Boulevard and East Avenue. We have had an opportunity to review your letter with Bob Schoenborn and Reed Flory of the City of Fontana. Some concerns have been raised on several recommendations in your letter and several items are in need of clarification. The items of concerns are listed below witli reference to the page number and paragraph in•yout letter of January 7th. I. Maintenance of the Dam (levee) for Proposed San Sevaine Basin No. 5 Page 1, Paragraph 3 Reference is made to the future increased maintenance costs by raising the proposed basin design height and the possible lack of maintenance personnnel to adequately inspect the proposed facility at the time of construction. The proposed basin will provide approximately 1,700 to •2,400 acre-feet of flood storage depending upon final levee design height. The. proposed basin is a major feature of Lite Day, Etiwand4 .and San Sevaine Creeks System Drainage Plan and will benefit both County.4re•as 1814 COMMERCENTER WEST • SUITE A • SAN BERNARDINO, CA. 92408 • (714) 885.4309 February 11, 1985 San Bernardino County Page two in allowing channel downsizing and will provide significaflt water con- servation benefits. The basin construction, as a part of the regional flood control system, will assist in allowing the development of the North Fontana area. The regional nature of the plan and the increased tax base due to the proposed development in the area should provide for future maintenance costs by Flood Control District personnel without having to form a maintenance district. We agree with the last sentence if the second paragraph on page two: "It is generally felt the benefit from the increased storage volume will outweigh the increased maintenance costs and environmental concerns. " Due to the potential costs and uncertainty involved with the establishing of a maintenance district, we need to resolve this issue as soon as possible. It should also be noted this basin is a major feature in the proposed San Sevaine Creek Bureau of Reclamation Project. 2. A pp roval of Alt "B" Page 2, Paragrap 3 There is some concern that the District has not accepted Alternatg , " B " as the preferred alternate. As far as the undersigned is c'oncdrned - ,. the flood control facilities proposed in Alternate "B" have been accepted and are recommended by the District. However, the recommendation-of the Alternate "B" facilities by the District should be clarified with the City. 3. Downst Dra Proble alo ,Banana Str eet Page 3, Pa ra raph 1 The last sentence includes, ".. but this does not address the downstream drainage problems along Banana Street ". The first phase of residential development is proposed between the existing Etiwanda and San Sevaine Channels outside the San Sevaine Creek overflow area. Therefore, the initial phase will have no effect on Banana Street. Later phases of development will require the relocation of San Sevaine Channel as recommended in Alternate Therefore, the flood flows will be removed from Banana Street. Addi- tionally, storm drains are proposed to handle onsite local flows. If the proposed commercial area to the east of the existing San Sevaine Channel develops prior to the proposed channel. construction, it will be necessary to mitigate onsite increased drainage flows with retention basins. 9 � • 5 u n II February ll, 1985 San Bernardino County Page three 4. Use of the Victoria Basin and _Lower San Sevaine Basin to Mitigate Increased Development Drainage Runoff We are working with the Cities of Rancho Cucamonga and Fontana and the District to develop sufficient storm storage volume to hopefully satisfy both needs. Additional storage volume can be provided in Victoria Basins by raising the levee height and by degrading the basin on a temporary basis. The turnout from the existing Etiwanda Channel is a. part of the Day, Etiwanda and San Sevaine Creeks Systems Drainage Plan and is a part of the proposed Upper San Sevaine Creek Bureau of Reclamation Project. 5. Phase I Recommendations II n Pages 3 and 4 Recommendation No. 5 states in this phase except the Victoria Basin to handle phase ". that " drainage facilities are scheduled expansion of San Sevaine Basin No. 5 and , the incremental flows generated by this n u n n u n 11. II This is not necessarily the case. A storm drain plan has been prepared .by Hall b Foreman, Engineers for the development. A schematic plan view of the plan is enclosed, Additionally, onsite retention facilities are proposed as part nf the plan although we are attempting to gain approval to provide the major part of onsite retention in the regional facilities. Recommendation No. 2 refers to the potential increased flow ,.in 'San „ Sevaine and Etiwanda Creeks. It is assumed the refe 1 rence'to,.increase in flows pertains to peak flows. If some flows are detained •upst ' ream, ;. and onsite, this may increase the duration of flows downstream.. 6. Phase II Recommendations Page 4 Recommendation No. 2 refers to increased flows ". It is assumed the reference. is to peak flows, as the duration of flow may be increased due to attenuation. 7. Phase. III Reco mmendations Page 5 Onsite drainage facilities are proposed as discussed in No. 5 above. We still believe the requirement of a downstream flowage acceptance 11 February JI, 1985 San Bernardino County Page four letter by the developer and /or the City is not warranted due to the historical flows by both Etiwanda and San Sevaine Creeks. We believe it can be shown that it will not be necessary and that the upstream property has aright to outlet flows in the historical watercourses if done in a reasonable manner. 8. General 1 Sincerely yours, The Day,.Etiwanda and San Sevaine Creeks Systems Drainage Plan has gone through the environmental review process and the EIR has been approved by the Environmental Review Board. It is assumed the EIR will fulfill the environmental review process for the Drainage Plan. However, it is recognized the plan revision to go to a higher .levee (dam) on the proposed Lower San Sevaine Basin may require a focused new EIR for that part of the project due to potential safety and aesthetic concerns. Due to the time constraints and the necessary time frame necessary in obtaining plan approvals, it will be necessary to begin design on the proposed flood control facilities in the very near future. We would like to meet with you at an early date to discuss procedures, hydraulic and design criteria. We appreciate the assistance your staff has provided in reviewing the proposed flood control facility plan, recognizing there are still some issues to resolve. > 'MAN/,/ . E Consulting Eigineer BCM:sw Encl as noted cc: City of Fontana attn: Bob Schoenborn Reed Flory Joe DiIorio Hall b Foreman attn: Hugh Foreman DEPARTMENT OF TRANS DRTATIONI COUNTY OF SAN BERNARDINO " �•ti; ENVIRONMENTAL t FLOOD CONTROUA1RPORTS �.11 1 PUBLIC WORKS AGENCY \1• 414 h \4111 h1f ' 825 East Third Street San Bernardino, CA 92415 -0835 (714) 383.1665 �% MICHAEL G. WALKER 1 .' Director March 5, 1985 File: 1- 701/1.00 1-801/1.00 124.0209 Bill Mann & Associates 1814 Commercenter West San Bernardino, CA 92408 Attention: Mr. Bill C. Mann Re: Zone 1, Etiwanda and San Sevaine Creeks — West End Specific Plan Gentlemen: _Reference is made to your letter dated February 11, 1985, in response to our letter dated January 7, 1985, commenting on your reports entitled "Flood + Control Facilities Study, West End Specific Plan" and the "Supplemental ' Report, Flood Control Facility Alternatives, West End Specific Plan ". Our comments are listed below as referenced in your February 11, 1985 letter and our January 7. 1985 letter. 1. Maintenance of the Dam (Levee) for Proposed San Sevaine Basin No. 5 A maintenance district may not be necessary in this case. The answer will come forth from policy being developed for detention basins. The staff recommended detention basin policy which goes to the Board of Supervisors, and the policy recommends further study of financing alternatives for construction and maintenance of detention basins and drainage (flood control) facilities. 2. Approval of Alternate "B" The District supports and recommends Alternate "B" over Alternate "A ". 3. Downstream Drainage Problems Along Banana Street As tentative maps are filed the effect of the proposed development on the downstream properties and the proposed mitigation measures will be reviewed in more detail. The proposed downstream mitigation measures are adequate for specific plan purposes. 4. Use of the Victoria Basin ar.d Lower San Sevaine Basin to Mitigate Increased Drainage Runoff We concur, but backup calculations and substantiation of \ agreement between the parties involved are still necessary. Letter to Bill Mann & Associates March 5. 1985 Page 2 5. Phase I Recommendations We generally concur with _y_Qur statements. We will also look at the increased duration of flow and the increased_ frequency of occurrence of damaging flow to determine if there is an adverse effect on the downstream properties.- 6. Phase II Recommendations See 5 above 7, Phase III Recommendations Flowage acceptance letters are quite often required as part. of development within the county. A flowage acceptance letter is only necessary if is lkely to be an the flow characteristics are changed Based onnthe there required calculations and adverse effect on the property. plans to be submitted, a determination will be made. ti 8. We concur with your statements. Anytime you wish to /need to meet regarding this project, please feel free to contact Allan J. Kielhold, Chief. Water Resources Division at (714) 383-2388, or myself at (714) 383 -120 Very truly yours. CHARLES L. LAIRD, Assistant Director Transportation /Flood Control /Airports CLL:RWC:mjs cc: City of Fontana, Bob Schoenborn /Reed Flory Joe Di Iorio Hall and Foreman, Hugh Foreman Ruben Montes Allan J. Kielhold 2. Alternate "B" Alternate "B" generally includes the construction of the ulti - mate San Sevaine Channel between the Devore Freeway and Foothill Boulevard, construction of an "interim" channel between Foot- hill Boulevard and the Santa Fe Railroad to the south, and the • excavation for some debris and storm flow capacity in the proposed Lower San Sevaine Basin. • Refer to Fi_gur.e No. 2 for a schematic location and description of the components of Alternative "B ". • Specifically, the features and estimated cost of Alternate "B" are as follows: • r- ? 2.1 Construction of the ultimate San Sevaine Channel (combined Etiwanda and San Sevaine Creeks flow) from the Devore Free, - r - way to Foothill Boulevard. Until the ultimate San Sevaine Channel is constructed below Foothill Boulevard in accor- , dance with the "Drainage Plan" and/or the Lower San Sevaine Basin is constructed, existing Etiwanda and San Sevaine Creek flows cannot be comi.ngl ed . Therefore, a trapezoidal concrete channel is proposed with ;i separator wall separa- ting the flows. Existing Etiwanda Creek flows would be directed to the existing RCB under Foothill Boulevard,and existing San Sevaine Creek flow; would be directed to the - proposed "interim" channel south of Foothill Boulevard.• • Due to the need to separate.Etiwnnda and San Sevaine Creek flows, the channel cost for this reach is higher than the channel in Alternate "A ". Estimated Cost = $ 5,175,000 • 2 . 2 Construction of an "interim" e a r t h channel along the ulti- mate channe,l alignment from F o o t h i l l Boulevard southerly 8 to connect to the existing San Sevaine Channel immediately south of the Santa Fe Railroad. The construction would include the ultimate road crossing structures. A set of schematic plans for the interim channel construction is included in the Appendix for gener.ral information only. Estimated Cost = $ 1,800,000 • 2.3 Develop "offsite" drainage retention capability in Victoria Basin and the Lower Snn Sevainc Basin to partially compen- sate for necessary "onsite" retention of drainage flows. Excavation in the Lower San Sevaine Basin would approximate 200,000 yd • Estimated Cost = $ 445,000 , 2.4 Develop 200,000 yd of debris storage in Lower San Sevaine Basin to provide for major flood debris production on San Sevaine Creek. Estimated Cost = $ 350,000 • • Subtotal = $ 7,770,000 2.5 Because of the area below the Devore Freeway tributary to the existing San Seval.ne Channel, it will be necessary to construct a channel or storm drain from the existing San Sevaine Channel to the proposed concrete lined channel for purposes of conveying local drainage flows to the channel. • The excavation of the Lower San Sevaine Basin does not pro- . vide for local dr;ii.nat;c flows north and northeast of the site originating southeasterly or the Dcvoro Freeway. The • • ] 0 storm drain or channel would be located along Baseline Avenue and is shown schematically on Figure No. 1. Storm Drain Estimated Cost = $ 1,000.000 Estimated Alternate "B" Cost = $ 8,770,000 As indicated in the discussion of Altornate "A ". the cost of the onsite storm - drain and drainage retention system is not included herein. Alternate "B as proposed herein, is approximately $2,500,000 less expensive than Alternate "A ". Ilowever, the facilities pro- posed under Alternate "A" are regional in nature and will provide benefits to the area in general, both to the north and south.of, the site. Components of Alternate "B" are also regional in natxure. 1. Alternate "B" will. provide direct benefits to the area along . Banana Street south of Foothill Boulevard at less expense to the xcgio.n. This alternate wi 11 not requi.r.e the complete ex- cavation of the Lower San Sevaine Basi..n i.nitially, and will re- serve the bulk of the material to be excavated for the construc- tion of the Foothill .Freeway, if needed. Because of the li.nhil n .ities ivolved with comingling Etiwanda and San Sevaine Creeks flows prior to an adequate concrete lined channel being constructed downstream of the project area, these flows must be kept separated. Therefore, a trapezoidal channel wi.th.a wall scpaxating the flows is recommended. A schematic depiction.of the channel is included herein as Figure No. 3. The final size and configuration of the channel cross- section will depend on final design or the rh:innel. system. 11