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Home My WebLink AboutVillage of Heritage Temporary Berm & Channel Plans11 11 1 VILLAGE OF HERITAGE TEMPORARY BERM & CHANNEL PLANS ALONG BASE LINE AVENUE IN THE CITY OF FONTANA COUNTY OF SAN BERNARDINO { ' PREPARED BY HALL & FOREMAN, INC. 3170 REDHILL AVE. COSTA MESA, CA 92626 MAY, 1988 1] III 91t 1 r [1 n D 17 fl 1 OR h 9 9 po"WAoovp 99co CIVIL ENGINEERING • LAND PLANNING • LAND SURVEYING SU ECT B DATE JOB NO. I / J SHEET OF �tSIGnJ ITC1�t�4 n mac.. oev\2 V�OL AVVI JKALA J SDe w. J � t �, ., — ram! N`�+� Gtr �, ✓�. � ( �� -/ - � sr /Z is�i' S2 7 9S LI P rl t Q - Q2 C��iSli • Cov�1� SZ 7 `� ��— 3 �-( SY _ 13 3.3 7 Fr l U 133.37 _ q 3 � 1. 3170 REDHILL AVENUE • COSTAMESA, CALIFORNIA 92626 -3428 • (714) 641 -8777 U N I T -• H Y D R O G R A P H A N A L Y G I S = *•* ***• *** ***** **** * **** ** *•x •**•*•*****•*•**•****•*•*•*•*•** ••* * * * * * * * * * * * **• **- * * * * ** * * *-* <<<; i{<<<<<(<<<<<<<<<<(((<<<<<<<<(<<<()>>)>)> ) > >> >)) >)> >>))>>)))) > >) > >))) > >> (C) Copyright 1983 Advanced Engineering Software EAES7 Especially prepared for HALL & FOREMAN, INC. (<<(<<<((((<(<<<<<<(<<((((<<<(<(((<((0)))1)1 ))) >>) >) >) >))) > >>)))))1))11) >)> **********DESCRIPTION D= RESULTS******************************************** A. 100 YR S STORM FLOW (EXIST. CONDITIONS) * FOR ARE NORTH OF BASE LINE AVE. ACROSS FROM INDUSTRIAL AREA * .. AHMED, 5/2/88 * ********•**•**••***•**•**•******•***** * ***• * * * * * * *• * * * *-* * * **• * * * *• ** *• *•* * * **• * * * *• * * * **• * * ** ****************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *. * * * * * * * * * * * * * * * * * * * * * * * * ** WATERCOURSE LENGT s 11500.000 FEE' LENGTH FROM CONCENTRATION POINT TO CEN I ROI D = 3833. 000 FEET ELEVATION VARIATION ALONG WATERCOURSE _ 257.000 FEET MPNN:ENG'S FRICTION FACTOR ALONG WATERCOURSE = .030 WATERSHED AREA = 331.000 ACRES WATERCOURSE "LAG" TIME = .346 HOURS UNIT HYDROGRAPH TIME UNIT = 5.000 MINUTES UNIT INTERVAL PERCENTAGE OF LAG -TIME = 24. 073 HYDROGRAPH BASEFLOW = 0.000 CFS MAXIMUM WATERSHED LOSS RATE (INCH /HOUR) = .560 LOW SOIL-LOSS RATE PERCENTAGE(DECIMAL) = . 5 0 VALLEY S- GRAPH SELECTED SPECIFIED PEAK 5- MINUTES RAINFALL (INCH) = .56 SPECIFIED PEAK 30- MINUTES RAINFALL(INCH) = 1.15 SPECIFIED PEAK 1 -HOUR RAINFALL (INCH) = 1.52 SPECIFIED PEAK 3 -HOUR RAINFALL(INCH) = 2.80 SPECIFIED PEAS( 6-HOUR RAINFALL. (INCH) = 4.15 SPECIFIED PEAK 24 -HOUR RAINFALL (I NCH =. 9.25 *HYDROGRAPH MODEL *1 SPECIFIED* PRECIPITATION DEPTH -AREA REDUCTION FACTORS: 5- MINUTE FACTOR = .995 30- MINUTE FACTOR = .995 1 -HOUR FACTOR = .997 3 -HOUR FACTOR = .999 6 -HOUR FACTOR = .999 24-HOUR FACTOR = .999 RUNOFF HYDROGRAPH LISTING LIMITS: MODEL TIME(HOURS) FOR BEGINNING OF RESULTS - 14.00 MODEL TIME(HOURS) FOR END OF RESULTS = 17.00 ((<<<(<<<<<(<( <(<< <((<< <( <<<(( < < << <((<)1)>) >> 1)))1))1 > > >))))))))111 > > >)))1 >) Advanced Engineering Software EAES3 SERIAL No. A0478A REV. 1.5 RELEASE DATE: 4/20/83 <<<<<<<<< <<((<<<<(<<�<<�<��<A��}�}>��>>��>>��}��>>��} UNIT HYDROGRAPH DETERMINATION ---- ---------- -------------�� INTERVAL "S" GRAPH UNIT HYDROGRAPH NUMBER MEAN VALUES ORDIWATES(CFS) �-_________-_________-___________________-___________-__-____________-_-____ 1 2.200 88.6980 2 9.361 286.629 N� 3 22.034 507.309 4 38.668 665.860 5 54.262 624.240 6 64.308 4N2.159 N� 7 70.788 259. 397 8 75.102 172.683 9 78.523 136.930 N� m� 10 81.341 112.804 11 83. 722 ' 95.332 N� 12 13 85.798 87.b24 83.10.2 69.090 14 88.999 59.054 15 90.403 56.180 16 91.518 44.641 17 92.556 41.549 18 93.38l 33.030 19 94.149 30.750 20 94.883 29.373 n� 21 95.600 28.710 2 96.186 23.468 N� 23 96.715 21.169 U� 24 97.215 20.015 25 97.715 20.015 26 98.215 20.015 N� 27 96.715 20. 015 28 99.215 20.01 i5 29 99.715 20.015 3el 100.000 11.401 �---------------------------------------------------------------------------- TOTAL SOIL-LOSS VOLUME(ACRE-FEET) = 130.5381 N� TOTAL STORM RUNOFF VOLUME(ACRE-FEET) = 124.3822 24-HOUR ST0RM m� RUNOFF HYDROGRAPH N� HYDROGRAPH IN FIVE-MINUTE INTERVALS(CFS) ------------------------------------------------------------------~^----- |� N� TIME(HRS) VOLUME(AF) Q(CFS) 0. 150.60 300.0 450.0 600.0 600.0 14.IZ83 46.5726 64.78 . Q . V . . . 14.167 47.0255 65.7G . Q . V . . . N� 14.250 47.4856 66.80 . Q . V . . . 14.333 47.9533 67.91 . Q . V . . . 14.417 48.4291 69.08 . Q . v . . . N� 14.500 48.9135 70.33 . Q . V . . . 14.583 49.4068 71.63 . Q . V . . . N� 14.667 14.750 48.9@92 5Q.4207 72.94 . 74.28 . Q G . V . . . . V . . . 14.833 50.9419 75.67 . Q . V . . . 14.917 51.4737 77.22 . Q . V . . . 15.000 52.0177 79.00 . Q . V . . . 15.063 52.5757 81.02 . Q . V . . . 15.167 53.1493 83.28 . Q . V . . . 15.250 53.7403 85.81 . Q . V . . . 15.333 54.3507 88.64 . Q . V . . . o� 15.417 54.9834 91.85 . Q . V . . . 15.500 55.6413 95.53 . Q . V . . . 15.583 56.3231 98.99 . Q . V . . . 15.867 57.0203 101.24 . Q . V . . . 1S.75et 57.7224 101.94 . Q . V . . . 15.833 58.4227 101.68 . Q . V . . . N� 15.917 59.1299 102.69 . Q . V. . ^ 16.OL40 59.8803 108.97 . Q . V. . . 16.083 60.9948 161.82 . Q V. . ~ N� 16.167 62.90@3 276.69 . . Q V . ^ 16.250 65.7516 414.01 . . .V 16.333 69.3557 523.31 . . . V . Q . 16.417 72.9917 527.95 . . . V . Q . N� 16.500 75.9191 425.07 . . . V Q . . 16.583 78.2061 332.06 . , . . Cl) V . . 16.667 @0.&>158 262.77 . . Q . V . . m� 16.750 @1.5633 224.70 . . Q . V . . 16.833 82.9462 200.80 . . Q . V . . 16.917 17.6900 84.2166 85.3997 184.45 . 171.79 . . Q . V . . .Q . V . . UNIT -HYDROGRAPH ANALYSIS <<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>}>>)>}>>>)}>>}>}>>>))))>) (C) Copyright 1983 Advanced Engineering Software [AES] I � Especially prepared for: HALL & FOREMAN, INC. <<<<(<<<<(<<<<<<>>>>}>>}>>>>}>>>>>>}>>>>>>>}>>>mm) OF ll *********DESCRIPTION 25 9R. STORM FLOW (EXIST. CONDITIONS) * FOR AREA NORTH OF BASE LINE ACROSS FROM INDUSTRIAL AREA * AHME0 * N� WATERCOURSE LENGTH = 11500.000 FEET LENGTH FROM CONCENTRATION POINT TO CENTROID = 3833.000 FEET ELEVATION VARIATION ALONG WATERCOURSE = 257.000 FEET N� MANNINGS FRICTION FACTOR ALONG WATERCOURSE = ~030 U� WATERSHED AREA = 331.000 ACRES WATERCOURSE "LAG" TIME = .346 HOURS UNIT HYDROGRAPH TIME UNIT = 5.000 MINUTES N� UNIT INTERVAL PERCENTAGE OF LAG-TIME = 24.073 HYDROGRAPH BASEFLOW = 0.000 CFS MAXIMUM WATERSHED LOSS RATE(INCH/HOUR) = .560 LOW SOIL-LOSS RATE PERCENTAGE(DECIMAL) = .550 o� VALLEY S-GRAPH SELECTED RUNOFF HYDRQGRAPH LISTING LIMITS: m� MODEL TIME(HOURS) FOR BEGINNING OF RESULTS = 14.069 MODEL TIME(HOURS) FOR END OF RESULTS = 17.00 it ((((< (<((( (((( ( <<<<< (<(<<({<<<(<<<<<(p}>>>>>>>>> mm) >m>>>>>>}>>>}>>} Advanced Engineering Software [AES] N� SERIAL No. A0478A — REV. 1"5 RELEASE DATE: 4/20/83 SPECIFIED PEAK 5-MINUTES RAINFALL(INCH)= .44 m� SPECIFIED PEAK 30-MINUTES RAINFALL(INCH) = .91 SPECIFIED PEAK 1-HOUR RAINFALL(INCH) = 1.20 SPECIFIED PEAK 3-HOUR RAINFALL(INCH) = 2.20 N� SPECIFIED PEAK 6-HOUR RAINFALL(INCH) = 3.29 SPECIFIED PEAK 24-HOUR RAINFALL(INCH)= 7.33 N� Y� *HYDROGRAPH MODEL #1 SPECIFIED* PRECIPITATION DEPTH-AREA REDUCTION FACTORS: 5-MINUTE FACTOR = .995 N� 30-MINUTE FACTOR = .995 1-HOUR FACTOR = .997 3-HOUR FACTOR = .999 N� m� 6-HOUR FACTOR = .999 24-HOUR FACTOR = .999 RUNOFF HYDRQGRAPH LISTING LIMITS: m� MODEL TIME(HOURS) FOR BEGINNING OF RESULTS = 14.069 MODEL TIME(HOURS) FOR END OF RESULTS = 17.00 it ((((< (<((( (((( ( <<<<< (<(<<({<<<(<<<<<(p}>>>>>>>>> mm) >m>>>>>>}>>>}>>} Advanced Engineering Software [AES] N� SERIAL No. A0478A — REV. 1"5 RELEASE DATE: 4/20/83 UNIT HYDROGRAPH DETERMINATION INTERVAL ----------- S"-GRAPH ---------- UNIT HYDROGRAPH ------------------- NUMBER MEAN VALUES ORDINATES(CFS) I I 11 11 E it 11 11 4 5 6 7 12 13 14 is 16 17 Is 19 20 21 2E 23 24 25 26 27 28 29 30 2.200 9.361 22.034 38.668 54. 26;7 64.308 70.788 75.102 78. 52.. 81.341 83.722 85.798 87.524 ea. 503. 90. 40- 91.516 92.556 93.361 94.149 94.883 95.600 96. 186 96.715 97.215 97.715 96.215 98.715 99. 215 99.715 100.000 88.080 286.629 507.309 665.860 624.240 402. 103 239.3S7 172. 68Z.-," 136. 930 112. 80A 95.332, 83. 10 21 69.090 59.054 56.160 44.641 41.549 33.030 30. 750 29.373 28.710 23.468 2i. 16 20. 015 20.015 20.015 20.015 20.015 20.015 11.401 it --------------------------- 7 --- .------ ..- .- ..---- . - --..- ---- .- .---- .--- -- ----- --- - - -- -- TOTAL SOIL-LOSS VOLUME(ACRE-FEET) = 104.6194 TOTAL STORM RUNOFF VOLUME(ACRE-FEET) = 97.3889 It --------------------------------------------------------------------------- I I I I I �� STORM RC�I'D FF HYDROGRAPH HYDROGRAPH IN FIVE-MINUTE INTERVALS(CFS) �N------------------------------------------------------------------------ TIME(HRS) VOLUME(AF> Q(CFS) 0. 100.0 200.0 30@.0 400.0 F____ . �9�3 36.9474 52.23 __________-____________-____________ . Q . V 14.167 37.3125 53.02 . Cl . V . . . 14.25Q 37.6El34 53.85 . Q . � 14.333 38.0603 54.73 . Q , V . . . N� 14.417 38.4436 55.66 . Q . V . . . 14.5690 38.8338 56.65 14.583 39.230I6 57.63 . D . V . . . N� 1� �67 ~ 39 6337 . 56.53 . Q . V . . . 14~75e.. 40.0424 59.34 . Q . V . . . N� 14.833 14 . 917 40.4564 40.6768 . 60.12 61.�4 . Q . O ~ V . . . . V . . . 15.69068 41.3N56 62.26 . Q . V . . . 15.083 41.7445 63.73 . Q . v . . . 15.167 42.1951 65.43 . [} . V . . . N� 25.250 42.6591 67.36 ' Q 15.333 43.1381 61:).55 15.417 43.634 72.1714 . Q ' V . . . N� 15 58)0 . 44 1502 . 74.91 . Q . V . . . 15.583 44.6847 77.61 . Q . V 15.667 45.23 79.37 . Q . V 15.750 45.7817 79.92 . Q . y N� 15.833 46.3307 79.72 . Q . V. . . 15.917 46"8855 80.56 . Q . V. . . 16.6900 47.4699 84.85 . Q N� 16.083 48.3233 123.92 - 16.167 49.7672 209.65 16.250 51.9129 311.56 . . .V .Q . 16.333 �.333 54. 615"D 392.35 . . ~ V . Q. N� 16.417 57.3325 394.58 . . . V . Q. 16. 500 59.5064 315.64 . . . V .Q . 16.583 61.2045 246.57 . . ^ QV ^ ^ N� 16.667 62.5574 196.45 . . Q. V . . 16.750 63.7248 169.50 . . Q . V . . 16.833 64.7745 152.42 . . Q V . . N� 18.917 65.7422 140.51 . . Q . V . . ~~ 17.0100 66.6458 131.20 . . Q . V . .. U Ll 0 0 J 1 Runoff Index Numbers of Hydrologic Soil -Cover Complexes For Pervious Areas -AMC II Quality of Soil Group Cover Type (3) Cover (2) A B C D NATURAL COVERS - Barren 78 86 91 93 (Rockland, eroded and graded land) 4:haparrel, Broadleaf Poor 53 70 80 85 (Manzonita, ceanothus and scrub oak) Fair 40 63 75 81 Good 31 57 71 78 Chaparrel, Narrowleaf Poor 71 82 88 91 (Chamise and redshank) Fair 55 72 81 86 Grass, Annual or Perennial Poor 67 78 86 89 Fair 50 69 79 84 Good 38 61 74 80 Meadows or Cienegas Poor 63 77 85 88 (Areas with seasonally high water table, Fair 51 70 80 84 principal vegetation is sod forming grass) Good 30 58 71 78 Open Brush Poor 62 76 84 88 (Soft wood shrubs - buckwheat, sage, etc.) Fair 46 66 77 83 Good 41 63 75 81 Woodland Poor 45 66 77 83 (Coniferous or broadleaf trees predominate. Fair 36 60 73 79 Canopy density is at least 50 percent.) Good 25 55 70 77 Woodland, Grass Poor 57 73 82 86 (Coniferous or broadleaf trees with canopy Fair 44 65 77 82 density from 20 to 50 percent) Good 33 58 72 79 URBAN COVERS - Residential or Commercial Landscaping Good 32 56 69 75 (Lawn, shrubs, etc.) Turf Poor 58 74 83 87 (Irrigated and mowed grass) Fair 44 65 77 82 Good 33 58 72 79 AGRICULTURAL COVERS - Fallow 77 86 91 94 (Land plowed but not tilled or seeded) RUNOFF INDEX NUMBERS SAN BERNAROINO COUNTY FOR HYDROLOGY MANUAL PERVIOUS AREAS E - 19 FIGURE' E -S(1 OF 2) I MEN OEM M III NMI M ops allmol M A HIM 0 ME of RINI M A in M 0 � IN I on on m ME M umm l 1 • ., • • 1 �1 =� 1�� M NM NEON I mmoomw� mEr ,j ME IVA mFAR IR IIA C FJ INFILTRATIN RATE FR PERVIUS AREAS VERSUS B RUNOFF INDEX NUMERS E - 21 FIGURE E - 6 a 1��l� ��II dNl��' 11 �_� wag _- CIVIL ENGINEERING • LAND PLANNING • LAND SURVEYING SUBJEC4� BY DATA JOB . SHEET OF _ �6 Oki< (0. 0) 3186-L AIRWAY AVENUE • COSTA MESA, CALIFORNIA 92626-4675 • (714) 641 -8777 Ono .. . ............... - ............ ...... loll------ ..-- ................. .. N. ....... m .....1..........NN.N.M loll. / / /11 ■. ■ ■._.■ ��... ■... �.../ / /.11 nunnn..■ u.ru�uu■un norm u..n■n■■■=■■uuu■■■uu smell Rollo •.N....... loll.. -- �...............1 ..l loss/ :::i1:1111 moo go" ....1..1.1...■ ■Or1OU1.. ■. nuuuo■■■■ ..undo ■ ■ ■■ loll. loll. . =i. lol=l .......... loll.. N... C =« i. ..N INN Mae nos HE S M C M MU. wNn 'INN 6 G D C C L �t L C 1 1 1 1 a 3.5 3 ?46: W U 2 �-AIIIIIIIIII � 2 a w c J J u. 1.5 Z Q ir 0.5 3.5 3 2.5 2 / SS 1.5 0 1 1 1 1 1 1 2 5 10 25 50 100 RETURN PERIOD IN YEARS NOTES 1. FOR INTERMEDIATE RETURN PERIODS PLOT 10-YEAR AND 100-YEAR ONE HOUR VALUES FROM MAPS, THEN CONNECT POINTS AND READ VALUE FOR DESIRED RETURN PERIOD. FOR EXAMPLE GIVEN 10 -YEAR ONE HOURS 0.85" AND 100 -YEAR ONE HOUR s 1.60 ", 25 ONE HOUR s 1.18 ". REFERENCE:NOAA ATLAS 2, VOLUME =-CAL.,1973 RAINFALL DEPTH VERSUS SAN BERNARDINO COUNTY RETURN PERIOD FOR HYDROLOGY MANUAL PARTIAL DURATION SERIES D -12 FIGURE D-2 P, nt n E D 0 F1 0 j A n = 0.015 1. Drainage area has fairly uniform, gentle slopes 2. Most watercourses either improved or along paved streets 3. Groundcover consists of some grasses - large % of area impervious 4. Main water course improved channel or conduit n 0.020 1. Drainage area has some graded and non - uniform, gentle slopes 2. Over half of the area watercourses are improved or paved streets 3. Groundcover consists of equal amount of grasses and impervious area 4. Main watercourse is partly improved channel or conduit and partly greenbelt (see n = 0.025) n 0.025 1. Drainage area is generally rolling with gentle side slopes 2. Some drainage Improvements in the area - streets and canals 3. Groundcover consists mostly of scattered brush and grass and small % impervious 4. Main watercourse is straight channels which are turfed or with stony beds and weeds on earth bank (greenbelt type) n 0.030 1. Drainage area is generally rolling with rounded ridges and moderate side slopes 2. No drainage improvements exist in the area 3. Groundcover includes scattered brush and grasses 4. Watercourses meander in fairly straight, unimproved channels with some boulders and lodged debris n = 0.040 1. Drainage area is composed of steep upper canyons with moderate slopes in lower canyons 2. No drainage improvements exist in the area 3. Groundcover is mixed brush and trees with grasses in lower canyons 4. Watercourses have moderate bends and are moderately impeded by boulders and debris with meandering courses n 0.030 1. Drainage area Is quite rugged with sharp ridges and steep canyons 2. No drainage Improvements exist in the area 3. Groundcover, excluding small areas of rock outcrops, includes many trees and considerable underbrush 4. Watercourses meander around sharp bends, over large boulders and considerable debris obstruction n 0.200 1. Drainage area has comparatively uniform slopes 2. No drainage improvements exist in the area 3. Groundcover consists of cultivated crops or substantial growths of grass and fairly dense small shrubs, cacti, or similar vegetation 4. Surface characteristics are such that channelitation does not occur SAN BERNARDINO COUNTY HYDROLOGY MANUAL E-8 r Ire t: -c 0 17 Dt E n L fift W49 9 2W,4*� / CIVIL ENGINEERING • LAND PLANNING • LAND SURVEYING ECT BY ( DATE 1 t 4105 NO. SHEET OF o - ? l 'I L 12.A�1 - 10 rJ (�-EGr Pi7A III) to ro -- ( I -+ L 1 u ('a I -+ Icy s - cu � C � 1c, cv) ic cl C V ": Par 1 A,Z� '�,�(.C'•r✓Y. n (/{/� ►f/ V1►1t�4t�1�/ � Y" Ic 3170 REDHILL AVENUE • COSTAMESA, CALIFORNIA 92626 -3428 • (714) 641.8777 CIVIL ENGINEERING • LAND PLANNING • LAND SURVEYING SUBJECT BV DATE JOB NO. SHEET OF �D-y a /+ a •II�O �f�s> a f = 0.793 I CJs f,KTo�' is �ot� 47w P� kf�D L/ as- 1 3.21 21 3170 REDHILL AVENUE • COSTAMESA, CALIFORNIA 92626 -3428 • (714) 641 -8777 Department of Water Resources Bulletin No. 195 Rainfall Analysis for Drainage Design Volume II. Long - Duration Precipitation Frequency Data October 1976 Claire T. Dedrick Secretary for Resources Edmund G. Brown Jr. Governor Ronald B. Robie Director The Resources State of Department of Agency California Water Resources OTHER VOLUMES OF BULLETIN NO. 195 (Bound separately) Volume I. Short - Duration Precipitation Frequency Data Volume III. Intensity- Duration - Frequency Curves Disclaimer Statement The contents of this report reflect the views of the CALIFORNIA DEPARTMENT OF WATER RESOURCES, which is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the CALIFORNIA DEPARTMENT OF TRANSPORTATION or the FEDERAL HIGHWAY ADMINIS- TRATION. This report does not constitute a standard, specification, or regulation. j., 0 1 Copies of Volume II of this bulletin at $10.00 each may be ordered from: State of California Department of Water Resources P. O. Box 388 Sacramento, CA 95802 Make checks payable to STATE OF CALIFORIQIA. California residents add 6 percent sales tax. ii El State of California EDMUND G. BROWN JR., Governor The Resources Agency CLAIRE T. DEDRICK, Secretary for Resources Department of Water Resources RONALD B. ROBIE, Director ROBIN R. REYNOLDS GERALD H. MERAL ROBERT W. JAMES Deputy Director Deputy Director Deputy Director CHARLES R. SHOEMAKER Assistant Director Division of Planning HERBERT W. GREYDANUS, Chief Virgil E. Whiteley . . . . Chief, Environmental Quality Branch This report was prepared under the direction of Robert L. McDonell. . . . . . . . . . Statewide Data Coordinator by James P. Goodridge . . . . Associate Engineer, Water Resources Assisted by William W. Lau. . . . . . . . . . . . Student Assistant Engineer John E. Baugher . . . . . . Associate Engineer, Water Resources George E. Blondin . . . . . . . . . . Senior Programmer /Analyst Travis Latham . . . . . . . . . . . . . . . . . Research Writer and CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT Boalin Wu . . . . . . . . . . . . . . . . . . . . . . Hydrologist iii J INTRODUCTION Bulletin No. 195, RainfaZZ AnaZysis for Drainage Design, comprises three volumes issued as separately bound publications that complement one another but are also useful as independent documents. Volume I contains short - duration precipitation data. This volume, Volume II, contains analyses of long- duration precipi- tation frequency records for storms lasting from one day to 60 days. Data on rainfall and snowfall are included. Volume III contains precipitation intensity - duration- frequency data. Volume I includes records of precipitation for storm durations shorter than one day recorded by gages having five or more years of record. Volume II includes selected data on daily rainfall frequency, with 20 or more years of record. The data include the following: All records evaluated during the past 15 years by the Department of Water Resources for spillway analysis. Records from stations that have been added to complete a minimum statewide grid. Comprehensive countywide data sets provided by j several county flood control districts. Records of gages having 70 or more years of daily rainfall record. Data on extreme rainfall contributed by many consulting engineers and private meteorologists. u 0 The daily depth- duration - frequency tables are arranged by drainage areas for all California stations with 20 or more years of record. (These areas are the major drainage provinces and hydrographic units shown on Plate 1.) The tables report data for periods of 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 30, and 60 consecutive days, and total annual precipitation. These are records from which the regional coefficients of skewness and variation used in Volume I were derived. The usefulness of time - related data depends on the fre- quency with which observations are made. However, data storage capacity limits the total amount of information that can be collected and analyzed economically. Restricting the data to an annual series of extremes, as has been done in this study, has simplified the maintenance of the data file. Only the greatest -1- u depth of rain for each year for the specific durations under study are reported here. Data Bank F I C 0 J C1 A permanent data bank containing long- duration data (for 1 to 60 days), reported here as Volume II, is filed in the Computer Systems Office of the Department of Water Resources on a seven - channel magnetic tape. The procedure for editing and updating the daily rainfall frequency data file is Computer Process 842. Data are retrieved and analyzed by Computer Process 843. The data are filed in this system by the drainage areas shown on Plate 1. The data bank is a truly cooperative enterprise between the Department of Water Resources and the agencies listed under "Acknowledgments ", which have contributed the data reported in Bulletin No. 195. The information filed in this bank is available to all cooperators in this study. The locations of those stations having 20 or more years of record are shown on Plate 2 and listed in the index. Limitations of Rain Gages A word of caution regarding the inadequacies of rain gage records is important to the user of this data. Both wind and snow can cause gages to underregister by preventing precipi- tation from entering the gage. Turbulent air reduces rainfall catch by deflecting the rain from the gage orifice. Its deflec- tion of snow is even greater. Snow also interferes with the functioning of the gage by occasionally forming a thick cap over the gage opening. The loss of record that ensues is usually unknown. It has not been possible, therefore, to correct these studies to account for such errors in the record. The data user should probably select a large return period or.use some other procedure as a safety factor under snowy conditions. Earlier Reports Two previous publications have been useful in preparing this report. In 1961, the U. S. Weather Bureau issued its Technical Paper No. 40 in which are summarized data for storm durations of 30 minutes to 24 hours and return periods up to 100 years. The paper's full utility was limited by rain frequency maps drawn to a scale of 1:10,000,000. In 1973, the National Weather Service published a rain frequency atlas for California`' in which the depiction of rain frequency in the State was improved by maps at a scale of 1:1,000,000. The atlas developed data for 6 -hour and 24 -hour storm durations and return periods up to 100 -2- Maximu Daily Rainfall Extremes of rainfall are best expressed in terms of statistical variation, rather than in inches of rain. Evaluating rainfall events as standard deviations above the mean provides a truer measure of maximum rainfall. When extreme rains are thus normalized, the highest values often are shown to have occurred at stations other than those that received the heaviest rains. This is demonstrated by the data shown in Table 1. In the North Coastal drainage province, for example, the extreme recorded daily rainfall occurred in 1949 at Gasquet Ranger Station, where the maximum daily precipitation was 474 millimetres (18.70 inches). This is 2.7 standard deviations above the mean. However, when the data are normalized, the extreme rains in that area are shown instead to have taken place in 1951 at Orick, where the maximum daily precipitation was 292 millimetres (11.50 inches), or 4.0 standard deviations above the mean. Occasionally the values for extreme recorded rainfall and the normalized extreme rainfall coincide at one station, as in the case of Lytle Creek in the Santa Ana drainage province. For the most part, though, such events are the exception. Table 1. REGIONAL RAINFALL EXTREMES FROM NONRECORDING RAIN GAGES Extreme Recorded Rainfall Normalized Extreme Rainfall Mean Meximum Mean Maximum Annual Daily Standard Annual Daily Standard Rainfall Rainfa ll Deviations _ Drainage* Rainfall Rainfall Deviation Year Province Station in Year in Above the Station in in Above the millimetre millimetre Mean 1 7 1n illimetres millimetres Mean (in inches) (in inches) inches) (in inches) North Coastal Gasquet Ranger 2 593 1949 475 2.7 Orick ( 7 1 815 ) 1951 (11 ?50) 4.0 Station (102.08) (18.70) San Francisco Lake McKenzie 1 168 1956 305 3.2 Mt. Hamilton 679 loss 230 4.2 La y (45.97) (12.01) Central Coastal boulder Creek 1 577 1959 319 1.8 Paicines 388 1956 142 3.9 (North) (62.10) (12.57) (15.29) (S.60) Central Coastal Juncal Dam 720 1969 406 3.2 Los Alamos 387 1918 148 3.6 (South) (28.36) (16.00) (15.22) (S.81) Los Angeles Hoegees 941 1943 522 3.3 Sawtelle 377 - 1934 239 4.1 (37.03) (20.57) (14.64) (9.40) Santa Ana Lytle Creek 839 1969 633 6.3 Lytle Creek 839 1969 633 6.3 (33.02) (24.92) (33.02) (24.92) San Diego Henshaw Dam 652 1927 368 4.0 Henshaw Dam 652 1927 368 4.0 (25.67) (14.46) (25.67) (14.48) Sacramento Hobergs 1 465 1938 361 2.9 Colfax 1 200 1965 162 4.1 River (57.68) (14.20) (47.57) (6.37) San Joaquin Crane valley 1 020 1956 230 2.S Hetch Hetchy 867 1951 (7 291 ) 3.6 River (40.16) (9.04) Tulare Lake Kern River 426 1967 331 4.9 Kern River 426 1967 331 4.9 Intake 3 (16.77) (13.02) Intake 3 (16.77) (13.02) North Lahontan Tahoe City 902 1945 190 2.0 Susanville 374 1963 119 2.9 (31.S6) (7.50) (14.72) (4.70) South Lahontan Squirrel Inn 1 018 1916 427 4.1 Independence 116 1967 145 4.4 (40.07) (16.81) (4.55) (5.72) Colorado River Raymond Flat 828 1938 343 2.7 Indio 79 1940 164 5.1 (32.60) (13.50) (3.12) (6.45) a See Plate 1 -3- 0 H- Standard rain gage of the type used to ; measure daily rainfall for the past 70 years. Support device and stakes secure these gages to the ground. Photo by Weather Measure Corp. -4- ANALYSIS OF THE DATA The equations of mean (X), standard deviations (S), the coefficient of skew (g) , the coefficient of kurtosis (k) , and the coefficient of variation (CV) are basic to this study. They are shown here: "! x - S - E (x) 2 N -1 _ NE (x) S g JN -1 N -2 S k = N2E(x)4 N -1 N -2 N- S S CV = — X Where X = the magnitude of an event and x = X - X E J The mean expresses the central tendency of the data set. The .standard deviation measures the deviation from the mean. The skew shows the lack of symmetry, or lopsidedness, that occurs in a rainfall data set due to bounding by a lower limit and virtually no bound on rains' upper limit. Kurtosis is used here to test for appropriateness of various frequency distributions. A number of probability distributions have been found to be adequate for hydrologic frequency analysis; these include the normal, exponential, Gumbel, log - normal, log Pearson's Type III, Pearson's Type III (Gamma), and Weibull distributions . For each distribution there exists a unique relationship between the coefficients of skewness and kurtosis. The Pearson's Type III distribution is used in this report. The precipitation depth - duration - frequency tables in this volume were prepared with the Department's Computer Program No. 3024. This program uses the general e uation for hydrologic frequency analysis from Chow's Handbook , which is: r 7 -5- TABLE 2 FREQUENCY FACTORS FOR PEARSON'S TYPE III DISTRIBUTION Rerurn Coefficient of Skew Period in Years .4 .5 .6 .7 .8 .9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2 _.07 - .08 - .10 - .12 •.13 - .15 x .16 _ .18 _20 _21 ...23 _.24 _.25 -.27 _28 ,_.29 _.31 5 .82 .51 .80 .79 .78 .77 .76 .75 .73 .72 .71 .69 .68 .66 .64 .63 .61 10 1.32 1.32 1.33 1.33 1.34 1.34 1.34 1.34 134 134 1.34 1.33 133 1.32 132 1.31 1.30 20 1.75 1.77 1.80 1.52 1.84 1.88 1.68 1.89 1.91 1.92 1.94 1.95 1.98 1.97 1.98 1.99 2.00 25 1.88 1.91 1.94 1.97 1.99 2.02 2.04 2.06 2.09 2.11 2:13 2.15 2.16 2.18 .. 2.19 2.21 2.22 40 2.14 2.19 2.22 2.27 2.31 2.35 2.38 2.42 2.45 2.49 2.52 2.55 2.58 2.61 2.64 2.66 2.69 • GO 2.28 2.31 2.36 2.41 2.45 2.50. 2.54 2.58 2.63 2.67 2.71 2.74 2.78 2.81 2.85 2.88 2.91 100 2.62 2.69 2.76 2.82 2.89 2.96 3.02 3.09 3.15 3.21 3.27 3.33 3.39 3.44 3.50 3.55 3.61 200 2.95 3.04 3.13 3.22 3.31 3.40 3.49 3.58 3.66 3.75 3.83 3.91 3.99 4.07 4.15 4.22 4.30 1,000 3.67 3.81 3.96 4.10 4.24 4.39 4.53 4.67 4.61 4.96 6.10 5.23 5.37 6.51 6.84 5.77 5.91 2,000 3.96 4.12 4.29 4.46 4.63 4.60 4.97 5.13 5.30 6.47 5.63 5.80 5.96 6.12 6.26 6.44 6.60 10,000 4.60 4.62 5.05 5.27 5.50 5.72 5.96 6.15 6.41 6.64 6.97 7.09 7.32 7.54 7.77 6.00 6.21 9.•. Figure I. 6 - - KURTOSIS 5 4 Based on 512 Stations with 3 _ 21,934 Station -years of records. 2 SKEW l VARIATION - -~ O l 2 3 4 5 6 8 10 15 20 30 60 365 DAYS VARIATION IN EXTREME PRECIPITATION STATISTICS WITH STORM DURATION -6- C P = Pi + KjS 'L) = (� - r - where j = return period in years i = specific storm duration in minutes, hours, or days Pji = precipitation in inches for return period j and duration i P. = mean maximum annual storm for duration i 1 K = frequency factor (in standard deviations) for return period of j years S. = standard deviation of maximum annual storm 1 for duration i The frequency factor (K) is from the Pearson's Type III Distribution and is related to the return period, as shown on Table 2. As an example of the significance of skewness in hydrologic frequency analysis, a 1,000 -year storm is defined as the mean plus 3.67 standard deviations for a skewness of 0.4 and the mean plus 5.91 standard deviations for a skewness of 2.0. Regional coefficients of skewness (Sk) are used because skewness is quite sensitive to large storm events in small statis- tical samples. The sensitivity of skewness was illustrated when the largest daily rainfalls from 79 daily rainfall records, each having 70 years or more of record, was normalized in terms of standard deviations in excess of the mean. The coefficient of determination between the normalized maximum daily rainfall and the coefficient of skewness was 0.74, indicating 74 percent of the variation in the coefficient of skewness is related to the size of the largest daily event in the rainfall record. Regional Coefficients Standard deviations of extreme annual rainfall are sub- ject to sizable random errors for small samples of years. To overcome the small sample problem, the standard deviations have all been converted to a dimensionless coefficient of variation (CV) by dividing the standard deviations by means. Averages of the coefficients of variation are quite stable over a broad range of storm deviations, as well as over a broad geographic region. The uniformity of the coefficient of variation with duration is illustrated on Figure 1, which shows a nearly uniform coefficient of variation for all storm durations from one to 60 days. This was based on statewide averages. The actual values selected for use in this report are shown on Table 3 for the 14 -7- Y�.'C��t��.t r1Y�L./Y/�iJ1W:WUY.fWa . r. n 0 L_ u • Shown in Figure 3. I I I -8- Table 3. REGIONAL COEFFICIENT OF VARIATION OF MAXIMUM ANNUAL SERIES PRECIPITATION i PRECIPITATION 3 Second Approximation - September 11, 1975 - October 14, 1975 1 Regions* Storm Duration in Days Days Y 1 2 3 1 .5 6 8 10 1 15 1 20 30 60 365 1 .351 .371 .365 .360 .356 .349 .340 .340 .341 .339 .335 .338 .268 2 .383 .424 .446 .464 .459 .449 .414 .400 .373 .364 .335 .331 .276 3 .443 .490 .525 .515 .521 .527 .513 .506 .482 .484 .448 .421 .329 4 .341 .8 .377 • .396 .397 .389 .384 .383 .380 .376 .387 .374 .365 .291 f 5 .348 .371 .372 .370 .361 .359 .364 .363 .363 .365 .369 .377 .924 S 6 .403 .8 .430 .430 .423 .420 .417 .410 .403 .402 .399 .393 .394 .-332 S 7 .376 .8 .408 .425 .434 .436 .437 .441 .427 .450 .439 .413 .422 .381 8 .455 1.2 .504 .515 .510 .505 .489 .484 .474 .459 .445 .424 .429 .364 } 9 .644 1.5 .718 .735 .739 .748 .748 .745 .730 .717 .698 .653 .637 .506 10 .409 1.1 .452 .474 .476 .480 .502 .501 .492 .489 .489 .478 .475 .403 11 .475 1.2 .531 .SS4 .565 .565 .576 .587 .575 .553 .542 .523 .519 .445 12 .494 .515 .528 .528 .526 .522 .521 .512 .513 .501 .481 .491 .416 13 .492 .532 .549 .543 .546 .S38 .548 .551 .551 .544 .527 .564 .501 14 .641 .641 .641 .641 .641 .641 .641 .641 .641 .641 .641 .641 .S55 *Shown in figure 2. 1.1 • 1.0 1.0 i 1.1 • Shown in Figure 3. I I I -8- Table 4. REGIONAL COEFFICIENT OF SKEW OF MAXIMUM ANNUAL SERIES PRECIPITATION 3 Second Approximation - October 14, 1975 Regions* Storm Duration in Days Y 1 2 3 4 5 6 8 10 15 20 30 60 365 i 1 1.1 1.3 1.2 1.1 1.1 1.0 .9 .8 .6 .6 .7 .7 .4 , 2 1.3 1.5 1.6 1.7 1.8 1.7 1.5 1.5 1.2 1.2 1.1 1.0 .6 3 1.3 1.6 1.5 1.4 1.3 1.3 1.1 1.0 .9 .9 .9 .8 ,t .5 4 1.1 1.2 1.1 1.0 .9 .9 .9 .8 .8 .8 .8 .8 .5 5 1.2 1.4 1.3 1.2 1.1 1.0 1.0 .9 .8 .7 .7 .8 .8 6 1.3 1.4 1.4 1.4 1.4 1.4 1.4 1.3 1.4 1.3 1.1 1.2 1.0 7 1.3 1.5 1.4 1.3 1.2 1.3 1.5 1.5 1.4 1.4 1.4 1.5 1.2 8 1.2 1.4 1.3 1.2 1.1 1.2 1.2 1.2 1.1 1.1 110 1.1 1.0 .n 9 1.4 1.3 1.3 1.4 1.4 1.4 1.2 1.2 1.1 1.0 1.0 1.2 3 . ..9 i 10 1.6 1.8 1.7 1.7 1.7 1.7 1.8 1.8 1.6 1.6 1.4 1.5 i , 1.1 11 1.2 1.3 1.2 1.1 1.1 1.0 1.0 1.0 .9 .9 .8 1.1 .9 12 2.0 2.0 1.9 1.9 1.8 1.8 1.8 1.8 1.7 1.6 1.8 1.6 1.1 13 1.6 1.5 1.6 1.6 1.5 1.4 1.3 1.2 1.2 1.1 • 1.0 1.0 i 1.1 • Shown in Figure 3. I I I -8- geographic zones shown on Figure '2. These values of CV were based on weighted mean values derived from the length of record. It is anticipated that these values will be periodically modified. The geographic zones were selected on the basis of similar values of CV. The chief problem with the CV values in Table 3 is demon- strated by the abrupt discontinuities between adjacent zones. To overcome these, lines of equal CV have been prepared for future consideration. They are shown in Plate 11. Perhaps some smoothing technique should be used in all of these 14 zones. The only zone, where smoothing was used was the southeast part of the zone, where the random fluctuations (in CV with duration) were felt to be excessive. The coefficient of skew (CS) was averaged in zones of similar values (Table 4). These are shown on Figure 3. Regional coefficients of skewness were selected to avoid the situation in which a projected rainfall event for a large return period at a short duration would exceed one for a long duration. Such a situation has occurred in previous reports. Frequency Distribution The criterion for the selection of a frequency distribu- tion to represent extreme annual precipitation for this report is the skew- kurtosis relationship shown on Figure 4, which shows curves representing log - normal, Weibull, and Pearson's Type III distributions, as well as points representing normal and Gumbel distributions. The data points represent weighted averages of skew and kurtosis from 512 daily rainfall measuring stations with 21,934 station -years of record. The Pearson's Type III dis- tribution is the clear choice for all storm durations up to 30 days. The Weibull distribution is the best choice for 60 -day storm durations and for yearly total rainfall. however, the Type III distribution is used throughout this study. Fixed - Interval Corrections Design storms provide the maximum values that are likely to occur for any duration, regardless of beginning and ending time. Weather observations, by contrast, are taken at a fixed time each day. Previous studies have shown that; on the average, the maxi- ' mum daily rainfall occurring in the wettest consecutive 1,440 minutes is 14 percent greater than that taken from a once -a -day observation made at a fixed time. The same fixed rainfall measurement interval exists, regardless of duration; that is, the maximum annual rain falling for 60 consecutive minutes is 14 per- cent greater than the clock -hour maximum rains observed at fixed intervals. These fixed interval corrections are described by Weisse as independent of the time interval under study and as equally valid when used to describe hourly, daily, or monthly extreme data. The values of clock -hour correction (which have been used in these studies) are shown in the following tabulation. -9- Figure 2. REGIONS OF UNIFORM COEFFICIENT OF VARIATION aQ Numbers refer to O values of CV on Table 3 O O ® O O O KIM Figure 3. REGIONS OF UNIFORM COEFFICIENT OF SKEW Numbers refer to values of skew on Table 4 —10— 0 u I I '4 Intervell Correction 1 2 3 4 5 6 8 10 1.14 1.07 1.04 1.04 1.03 1.02 1.02 1.01 The interval can be in any uniform time increments. hour corrections also become calendar -day corrections uniform once -a -day observation time is used. Partial Duration Series and Annual Series These clock - when a Two methods exist for extracting the extreme values of time series data: using either the highest value of a total series, regardless of the time it occurs, or the highest value for each year. The analyzed results affect only relatively short return Periods because, for periods longer than ten years, the two series merge into one. f The partial duration series are those values that exceed a given base level, no matter when they occur. With this series, an analysis may include one year in which several large floods occurred and other years in which no storm as large as the base level occurred. The partial duration series is used for studying storms that have return periods of less than five years; longer return periods show little substantial difference. Partial duration series analysis requires the data analyst to use foresight in selecting a base level of storm events for a predetermined number of data points. The annual series consists of the largest annual value for each year, with only one value per year. Langbein compared the results of the annual series to the partial duration series,as shown by the following conversion factors. Return Period in Years 0 I I u n Annual Series 0.5 1.0 2.0 5.0 10.0 100.0 Partial Duration 1.16 1.58 2.54 5.52 10.5 100.5 Series The annual series provides one great advantage over the partial duration series: ease of data file management. When the files of extreme data are updated, one year's record can be added to the data file for each year without regard to prior data files. Depth- Duration - Frequency Tables The depth - duration - frequency tables in this report have several parts. The first part with station number, station name, elevation, location, and county code is described in "Key to Station Descriptions" in this volume. -11- r. Figure 4. 6 5 N N 0 ►- q o: M Y Norm a V rtosis hip for (uration Log-Normal Gum bel 6 ' Skew -Ku !O relations �s Various t JO in days w ,�, Pears T on's a 1 Type III Weibu11 Based on daily rain gage records 2 1 2 SKEW SKEW - KURTOSIS RELATIONSHIP WITH CRITERIA FOR THREE FREQUENCY DISTRIBUTIONS -12- ®i I N The second part of the tables is a matrix of columns of storm events ranging from 1 day to 60 days, including the annual total precipitation, and return periods ranging from 2 to 10,000 years, with a probable maximum precipitation (PMP) estimated as the Wean plus 15 standard deviations. The calendar, fiscal, or water year total precipitation is coded as C YR , F YR , or W Y R , or when unspecified, as 365 D . The third part of the table contains the mean, which is the arithmetic average; the clock -hour correction, where used; the calculated skew; the regional skew; and the actual skew, which is used on the computations for the duration - return period matrix. The fourth part of the table contains the kurtosis, which is the fourth moment function. II The number of data points used in the computations for each column is coded as N. The year in which the highest .rainfall of record occurred is coded as Record Year. The highest precipitation for each duration is indicated in the row labeled Record Maximum Normalized Max is •the record maximum in units of standard deviations in excess of -the mean for each duration. The calculated coefficient of varia- tion is coded as Calc. Coef. of Var The regional coefficient of variation is coded as Regn. Coef. Var The coefficient of variation used in this report is coded as Used Coef. Var The fifth part of the table contains dimensionless ratios of precipitation for return periods of 10 to 10,000 years, expressed as percentages of the mean annual precipitation. These are coded as RP 10 /A, etc. PMP is also expressed as PMP /A (probable maximum precipi.t o expressed as a fraction of the mean annual rainfall (A) ) , so that the mean annual precipitation can easily be used as an interstation interpolating device, as well as a means of comparing adjacent records for consistency. The data user is expected to be concerned mainly with the first two parts of the table. The remainder of each is printed in the interest of continued procedures development. 4 'tat 1S states: "Where N is small, results are not dependable ". In this application, "small" means records of 25 years or less. From sampling theory is derived the concept: errors are propor- tional to one over the square root of the sample size. Safety Factors in Hydrology Engineers are accustomed to using safety factors in the design of structures. In hydrology, safety factors have con- sisted of designing for "spillway design floods ", "project design floods% "1,000 -year storms ", "probable maximum precipitation ", and other bases for rationalizing the use of very rare storm H, -13- d Figure 5. RELATIONSHIP OF PERMISSIBLE LEVEL OF RISK AND RETURN PERIOD Return period (RP) in years I 1.000 1 0 100 1000 10,000 100 ,000 n 1 2 10 20 10 200 ecl Life in Yea rs on o CL ( I a RP= 1 -(1 -J) Ph .100 Source I Linsley, Kohler and Pouikus f 1 Hydrology for Enpineers,l9SJ - a Y 0 ., A10 e pq r ;o c N C (Pearsont Type M, Skew E E E er .001 O 1 2 ' Standard 4 5 6 7 8 deviations above the mean i t ■ 3 —14— : events in design of flood protection structures. The fact that design storms are occasionally exceeded points out the need for an assessment of the risks of failure associated with selected return periods. Frequency analysis defines the event which can be expected once every "Y" years, on the average. This does not imply that a "Y -year event" will occur regularly every "Y" years. Return periods, as well as flood magnitudes, are subject to analysis. For example, there is a two percent chance that a 50 -year event will occur in any one year. The 10,000 -year event with a skew of 1.3 is defined as the mean plus 6.64 standard deviations, as shown on Table 2. The 10,000 -year return periods based on 10 to 30 years of record will be considered to have low statistical reliability. However, their use in hydrologic studies has considerable utility and compensates for this disadvantage. Since some hydraulic structures have design lives of 100 years and since a low level of risk, such as a one -in -a- hundred chance of failure, is desirable, the joint probabilities of the two events are calculated by multiplying, in this case, a one -in -a- hundred risk with a 100 -year project life for a design return period of 10,000 years. The permissible level of risk during the life of a project can be considered when a return period is selected. A project with a one -year useful life, for which a one percent chance of failure would constitute a permissible level of risk, would be designed for a return period of 100 years. The relationship of permissible level• of risk and return period is shown on Figure 5 for a broad range of project lives and return periods. The graph was prepared from a probability formula in Hydrology for Engineers (Linsley, Kohler, and Paulhus, 1958) It indicates that there is a 10 percent chance of a once -in -460 -year event occurring in the next 50 years. Permissible risk in discussed in a paper by Ben Chie Yen. 13 Meterological models of the precipitation mechanism have been based on three physical limitations: • Moisture in the air over a basin • Moisture carried into a basin by winds ° The fraction of the inflowing moisture that will precipitate These variables, although difficult to measure directly, are commonly estimated for orographic and convective storm types. Models of the precipitation mechanism are frequently calibrated C by historical precipitation data. A good discussion of probable maximum precipitation was prepared in 1967 by Vance Myers of the U. S. Weather Bureau. ' Statistical models represent a direct approach to estimating PMP with a minimum amount of assumption. A comparison of these two approaches to PMP computing was made by Hershf ield, 1 0 who used the mean plus 15 standard deviations to estimate prob- able maximum precipitation. The value of 15 standard deviations was an upper enveloping value for extreme storms of record. The use of a given level of risk or a given number of standard deviations above the mean can be a management decision, when a relatively stable method of computing the means, standard devia- tions, and skew coefficients is available. L F C� i -16- i 1 1 �i i s Advanced Engineering Software [AES] N� SERIAL No. A0478A m� REV. 1.5 RELEASE DATE: 4/20/83 UNIT HYDROGRAPH DETERMINATION ------------------------------------------------------------------------- _N� T RVAL "S" GRAPH UNIT HYDROGRAPH N�NUMBER MEAN VALUES ORDINATES(CFS) ______________________________________________________________________ 1 2.048 47.566 2 8.476 149.251 N� 3 19.784 262.568 4 35.085 355.290 5 50.621 360.735 N� 6 61.570 254.237 7 68.620 163.714 8 73.369 110.259 9 76.877 81.471 10 79.813 68.173 11 82.276 57.190 12 84.416 49.676 13 86.276 43.195 14 8 36.165 15 89.200 31.740 N� 16 90.505 369.306 |� - 17 91.540 24.6912 18 92.521 22.780 19 93.305 18.220 0� -V 20 94.030 16.819 21 94.726 16.171 22 95.405 15.774 @� l� 23 96.008 14.@04 24 96.508 11.61W N� 25 26 97.008 97.508 11.610 11.610 U� 27 98.008 11.610 28 98.508 11.610 29 99.008 11.610 30 99.508 11.61el 31 100.000 11.414 _ --------- _----------------- ________------- ----------------------- __ V AL SOIL-LOSS �OLUME(ACRE-FEET) = 75.7246 _TOTAL STORM RUNOFF VOLUME(ACRE-FEET) = 72.1864 ML ---------------------------------------------------------------------- 24-HOUR STORM N� RUNOFF HYDgOGRAPH N� HYDROGRAPH IN FIVE-MINUTE INTERVALS(CFS) 1I I > VOLUME(AF) Q(CFS) 0. 100.0 200.0 300.0 400.69 ----------------------------------------------------------------------- 1 083 26.9250 37.41 . Q . V 1 167 27.1865 37.97 . Q . V 1N�250 27.4521 38.57 . Q . V . . . 14.333 27.7221 39.20 . Q . V . . . 1 417 27.9966 39.87 . Q . V . . . 1N�500 28.2761 40.58 . Q . V . . . 14.583 28.5607 41.32 . Q . V . . . 1 667 28.8505 42.07 . Q . V 1 750 29.1455 42.84 . Q . V . . . X��833 29.4460 43.64 . Q . V . . . I ��17 29.7526 44.51 . Q . V . . . 1 000 30.0660 45.51 . Q . V . . . 1��6D83 30.3873 46.65 . Q . V . . . 15.167 369.7174 47.93 . Q . V . . . 1 jR50 31.69573 49.36 . Q . V . . . � 333 31.4082 50.96 . Q . V . . . 1 31.7716 52.77 . Q . V . . . 1 500 32.1493 54.84 . Q . V 1 583 32.54�05 56.80 . Q . V . 1 �� 32.9410 58.16 . Q . V . . . I .j0 33.357 58.76 . Q . V . . . 1 ��3�� 33.7507 58.80 . Q . V �� 1 917 34.1591 59.30 . Q . V . . . 16.000 34.5896 62.51 . Q . V. . ~ 1 o83 35.2159 90.94 . Q. V. 1 167 36.2523 150.48 . . Q V . . I��250 37.7816 222.05 . V Q . . 333 39.7429 284.79 . . . Q . . V �� 417 41.@194 3N1.50 . . V Q . . ��5069 43.5760 255.06 . . . VQ . . 16.583 44.9601 20N.98 . . Q V . . 667 46.69606 159.78 . . Q . V . . 1N� 69 7� 46.9799 133.49 . . Q . V . . 1 47.7985 118.87 . .Q . V . . 1 917 48.5467 108.64 . Q . V . . � 16900 fl 49.2428 101.06 . Q . V . . I U N I T- H Y D R O G R A P H A N A L Y S I S ' (C) Copyright 1983 Advanced EnQineerinn CAES1 Especially prepar for ' HALL & FOREMAN. INC. �****DESCR I P T I ON OF RE 0A YR. FLOW FOR EXISTING CONDITIONS FOR AREA NORTH OF BASE LINE AVE.. C SS FROM I AREA � H D SHEIKH, 0/24/88 WATERCOURSE LENGTH = 13000.000 FEET ' LENGTH FROM CONCENTRATION POINT TO CENTROID 3840.000 FEET ELEVATION VARIATION ALONG WATERCOURSE = 270.000 FEET MANNINGS FRICTION FACTOR ALONG WATERCOURSE _ .030 WATERSHED AREA = 192.000 ACRES WATERCOURSE "LAG" TIME = .368 HOURS UNIT HYDROGRAPH TIME UNIT = 5.000 MINUTES UNIT INTERVAL_ PERCENTAGE OF LAG -TIME = 22.644 ' HYDROGRAPH PASEFLOW = 0.000 CFS MAXIMUM WATERSHED LOSS RATE(INCH /HOUR) = .560 LOW SOIL -LOSS RATE PERCENTAGE(DECIMAL) = .550 VALLEY S -GRAPH SELECTED SPECIFIED PEAK 5- MINUTES RAINFALL(INCH)= .56 SPECIFIED PEAK 30 -M I NLJTES RAINFALL. (I NCH) = 1.15 1 SPECIFIED PEAK 1 -HOUR RAINFALL(INCH) = 1.52 SPECIFIED PEAK 3 -HOUR RAINFALL(INCH) = 2.80 SPECIFIED PEAK 6 - HOUR RAINFALL(INCH) = 4.15 ' SPECIFIED PEAK 24 -HOUR RAINFALL(INCH)= 9.2', *HYDROGRAPH MODEL #1 SPECIFIED* ' PRECIPITATION DEPTH -AREA REDUCTION FACTOR'�s 5- MINUTE FACTOR = .997 30- MINUTE FACTOR = .997 ' 1 -HOUR FACTOR = .998 3 -HOUR FACTOR = .999 6 -HOUR FACTOR = .999 ' 24 -HOUR FACTOR = 1.000 RUNOFF HYDROGRAPH LISTING LIMITS: MODEL TIME(HOURS) FOR BEGINNING OF RESULTS = 14.00 MODEL TIME (HOURS) FOR END OF RESULTS = 17.00 *} NOTE: RATIO OF (AREA IN SQUARE FEET) / (WATERCOURSE LENGTH SQUARED) IS NOT BETWEEN [.I@] AND [1.01 ,, L� HYDRAULIC ELEMENTS - I PROGRAM PACKAGE ========================================================================== < ((< <(<<<<<<<<< <<0>>>>>>m>>>}>>>>>>>>>>>>>>>>} (C) CODyripht 1982,1966 Advanced Engineering Software LAES3 Especially prepared for: HALL & FOREMAN, INC. V <(((((<(<((( (( <( <( (< � ell << ((<<( (((<0>)))))>>>>>) )))>>>)>>))>>)))>>>>)) ))'i )>>>>)>>}> __________________________________________________________________________ <(<<<<<<<<<<<<<<<(<<>>)>>>>)}))}>>}}>>>>>>>>>>>>>>>>>>>>>> ~- Advanced Enpineering Software [AES'j SERIAL No. 100821 N� VER . 2 . 3C RELEASE DATE: 2/20/86 DESCRIPTION OF RESULTS******************************************** N �BASE LINE AVE. DITCH STA.6673.5 TO 7831.00 * w� * * 0 = 434.87 CFS * AHMED,5/24/88 t -- ))CHANNEL INPUT IWFORMATION<<<( _____------------------------CHANNEL Z(HORIZONTAL/VERTICAL) = 2.00 BASEWIDTH(FEET) = 35.00 N� CONSTANT CHANNEL SLOPE(FEET/FEET) = .005600 UNIFORM FLOW(CFS) = 434.87 MANNINGS FRICTION FACTOR = .02569 N� NORMAL-DEPTH' FLOW INFORMATION: __________________________________________________________________________ )>))} NORMAL DEPTH(FEET) = 1.83 N� FLOW TOP- WIDTH(FEET) = 42.30 — FLOW AREA(SQUARE FEET) = 70.55 HYDRAULIC DEPTH(FEET) = 1.67 N� FLOW AVERAGE VELOCITY<FEET/SEC.> = 6.16 U� ~~ UNIFORM FR8UDE NUMBER = .841 PRESSURE * MOMENTUM(POUNDS) = 9085.93 AVERAGED VELOCITY HEAD(FEET) = .590 SPECIFIC ENERGY(FEET) = 2.415 CRITICAL-DEPTH FLOW INFORMATION: N�_____________-------------------------------------------- CRITICAL FLOW TOP-WIDTH(FEET) = 41.53 CRITICAL FLOW AREA(SQUARE FEET) = 62.45 CRITICAL FLOW HYDRAULIC DEPTH(FEET) = 1.50 N� CRITICAL FLOW AVERAGE VELOCITY(FEET/SEC.) = 6.96 CRITICAL DEPTH(FEET) = 1.63 CRITICAL FLOW PRESSURE + MOMENTUM(POUNDS) = 8957.92 N� AVERAGED CRITICAL FLOW VELOCITY HEAD(FEET) = .753 CRITICAL FLOW SPECIFIC ENERGY(FEET) = 2.385 1 1 � • CIVIL ENGINEERING • LAND PLANNING • LAND SPIMM M No ITA - 79, V - ob To 79//. o o A k etq P. Pc=- 36 2- Is , 4 2– ( , e� Y- .0 .2t4 cks r,��. 1 .. L PD IL � = I. � ; O.�f�1 �-. _r ' /3o Q, 33 .r J•N�Z_ 130. �/l� 13o8,'t9 ' _ - r ___._ �>c- � + ►. 2 �� f �� - 777 +t•K -� � y7 � 1 46 (4 S4 ............... ......... ............... ......... \0 00 3170 REDHILL AVENUE • COSTAMESA, CALIFORNIA 92626-3428 • (714) 641-8777 I ****DESCRIPTION OF .T 7911-00 TO 6839.21 11 133 37 CFS )JANNEL - INPUT - INFORMATION(<<< ------------------------------------------- - ----- ----- --------------- ANNEL Z(HORIZONTAL/VERTICAL) = 2.00 SEWIDTH(FEET) = 10.00 NSTANT CHANNEL SLOPE(FEET/FEET) .01150► IFORM FLOW (CFS) = 133.37 MANNINGS FRICTION FACTOR = .0250 = 9 RMAL-DEPTH FLOW INFORMATION: -------------------------------------------- I ))) NORMAL DE FEET ) = 1.47 OW TOP- WIDTH(FEET) = 15. OW AREA(SQUARE FEET) HYDRAULIC DEPTH(FEET) = 1.20 11 OW AVERAGE VELOCITY(FEET/SEC.) IFORM FROUDE NUMBER = 1.123 PRESSURE * MOMENTUM(POUNDS) N ERASED VELOCITY HEAD(FEET) ECIFIC ENERGY(FEET) = 2.232 90 19.09 6.99 26 09 .758 ITICAL-DEPTH FLOW INFORMATION: ------------------------------------------------------------------------ - ICAL FLOW TOP-WIDTH(FEET) = 16.33 .fICAL FLOW AREA(SQUARE FEET) = 20.82 9 ITICAL FLOW HYDRAULIC DEPTH(FEET) = 1.28 ITICAL FLOW AVERAGE VELOCITY(FEET/SEC.) = 6.40 CRITICAL DEPTH(FEET) = 1.58 K ITICAL FLOW PRESSURE + MOMENTUM(POUNDS) = 2600.76 ERASED CRITICAL FLOW VELOCITY HEAD(FEET) .637 ITICAL FLOW SPECIFIC ENERGY(FEET) = 2.219 I I 11 I �I I I * * * * ** *DESCRIPTION OF T1133.37CFS 8839.21 TO STA. 10173.00 HMEn.5 /20/88 NANNEL INPUT INFORMATION(((( ANNEL Z(HORIZONTAL /VERTICAL) = 2.00 BASEWIDTH(FEET) = 10.00 NSTANT CHANNEL SLOPE(FEET /FEET) _ .009200 IFORM FLOW(CFS) = 133.37 MANNINGS FRICTION FACTOR = .0250 RMAL -DEPTH FLOW INFORMATION: I )>) NORMAL DEPTH(FEET) = 1.57 OW TOG- WIDTH(FEET) = 16.26 OW AREA(SGUARE FEET) = 20.56 HYDRAULIC DEPTH(FEET) = 1.26 OW AVERAGE VELOCITY(FEET /SEC.) = 6.49 IFORM FROUDE NUMBER = 1.016 PRESSURE + MOMENTUM(POUNDS) = 2601.08 ERASED VELOCITY HEAD(FEET) _ .653 ECIFIC ENERGY(FEET) = 2.219 ITICAL -DEPTH FLOW INFORMATION: d� - ICAL CK.fICAL ITICAL ITICAL CRITICAL ITICAL ERASED ITICAL C 1 C 1 FLOW TOP-WIDTH(FEET) = 16.33 FLOW AREA (SQUARE FEET) = 20.82 FLOW HYDRAULIC DEPTH(FEET) = 1.28 FLOW AVERAGE VELOCITY(FEF_T /SEC;.) = DEPTH(FEET) = 1.58 FLOW PRESSURE + MOMENTUM(POUNDS) = CRITICAL FLOW VELOCITY HEAD(FEET) _ FLOW SPECIFIC ENERGY(FEET) = 2.219 6.40 2600. 76 .637 1 T11 10173 * TO 10506.21 HMFn * 5/20/88 U� CRANN Z(HORIZQNTAL/VERTICAL) = 2.00 SEWIDTH(FEET) = 10.00 NSTANT CHANNEL SLOPE(FEET/FEET) = .013200 IFORM FLOW(CFS) = 133.37 | ANNINGS FRICTION FACTOR = .0250 ' ================================================================ RMAL-DEPTH FLOW INFORMATION: '--~---------------------------------------------------------------------- NORMAL DEPTH(FEET) = 1.42 OW TOP- WIDTH(FEET) = 15.67 lOW AREA(SQUARE FEET) = 18.19 HYDRAULIC DEPTH(FEET) = 1.16 S AVERAGE VE�L8CITY(FEET/SEC.) = 7.AVERAGE XFORM FROUBE NUMBER = 1.199 OW PRESSURE + MOMENTUM(POUNDS) = 2640.19 ERAGED VELOCITY HEAD(FEET) = .835 %FIC ENERGY(FEET) 2.252 ITICAL-~DEPTH FLOW INFORMATION: ---------------------------------------------------------------------- 'ICAL FLOW TOP-WIDTH(FEET) = 16.33 c�°fICA- FLOW AREA(SQUARE FEET) = 20.82 S ITICAL FLOW HYDRAULIC DEPTH(FEET) = 1.28 ITICAL FLOW AVERAGE VEL8CITY(FEET/SEC.) = 6.40 CRITICAL DEPTH(FEET) = 1.58 l ITICAL FLOW PRESSURE + MOMENTUM(POUNDS) = 2600.76 E0AnED CRITICAL FLOW VELOCITY HEAD(FEET) = .637 ITICAL FLOW SPECIFIC ENERGY(FEET) = 2.219 L� M L „ t 1 / 52 co / w Ga gin g 26 ♦♦ w ��.� 2� ♦� 44 15 '• l4 HIGHLAND* qw Well '.r it .♦ j � ♦ iii II ♦ Q ,n ♦ ' ♦ I +\ II � / ••O ii ♦ III ii 192 AC. U ♦ , ii i ! Vl ♦� /00 — O O I i i .♦ C.F. vim' Q /Gtr ==,627.9.5 i = 394 5B C.FS. i II s. vsoo =.a .xc Q /cb "q25 = I P7 97 C.F.S. ., . ♦ II ♦ I I a, ! ♦ ♦ 1 �r ♦ 45 �.� k # 0=11 ,9 = 4',o - q25 = 13737C`F511�♦ Bic— 137.37 — — BA 'ALINE f1l�E• I o i l .• �' . A . GILFILLAN • • %1m Iv FONTANA 1178 REBNILL AVENUE COSTA MESA. CA 92828.1128 CMLENDINE[NIND • LANDVLANNINO • LANDSUIIV[YIND HYDROLOGY MASTER PLAN DATE SCALE DRW. 11/86 i