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Home My WebLink AboutSWP272156(1) • LEVEL I DRAINAGE ANALYSIS AND DISCUSSION OF CORE AND SPECIAL REQUIREMENTS FOR TALL FIRS TOWNHOUSES LOCATED AT SUNSET BOULEVARD (AKA DUVALL AVENUE N.E.) RENTON, WASHINGTON OUR JOB 4168 JANUARY 8, 1991 BARGHAUSEN CONSULTING ENGINEERS, INC. 18215 - 72ND AVENUE SOUTH KENT, WASHINGTON 98032 (206) 251-6222 •• j��s�F m • 4168.002 -1- AS/mh LEVEL I DRAINAGE ANALYSIS AND DISCUSSION OF CORE AND SPECIAL REQUIREMENTS FOR TALL FIRS, RENTON, WASHINGTON OUR JOB 4168 JANUARY 8, 1991 INTRODUCTION/GENERAL INFORMATION The project lies within a portion of the Southwest quarter of Section 3, Township 23 North, Range 5 East, Willamette Meridian, King County, Washington, and is approximately 3.2 acres in size. The existing site consists of three houses located at the south portion of the property along Sunset Boulevard. The remainder of the area is undeveloped and is covered with evergreen and douglas fir trees and undergrowth consisting of many forms of grass and shrubs. The property is basically trapezoidal in shape and contains approximately 314 feet of frontage to the south along Sunset Boulevard. The property is bounded to the north by undeveloped properties and existing residential houses, to the east by the existing Summer Wind subdivision, and to the west by Shannon Village commercial and business center. The overall topography of the site generally slopes from north to south with an approximate slope of 6 to 8 percent. The on-site soil has been classified as Alderwood gravelly sandy loam in accordance with the King County soils survey map. The proposed project is for construction of a 37-unit townhouse project. UPSTREAM DRAINAGE CONSIDERATIONS From the site visit and existing topographic map of the project, it is apparent that the site does not . receive any storm drainage runoff from upstream properties. The north property line of the property is located at the ridge line of the land and the property to the north drains away from the project. Properties to the east and west have already been developed and contain their own storm drainage system. The project is bounded to the south by Sunset Boulevard and does not receive any storm drainage runoff from the south due to the topography. ON-SITE DRAINAGE CONSIDERATION As mentioned above, the site drains from north to south with an average slope of approximately 6 to 8 percent. Storm drainage runoff from the site will sheetflow toward Sunset Boulevard and be collected by two existing catch basins located at the north portion of the road. These two existing catch basins collect the storm drainage runoff from the subject property and some of the upstream tributary area. The proposed project provides detention and biofiltration in the form of a grassline swale for treatment of the on-site stormwater prior to discharging to these catch basins. Please refer to the upstream tributary area map enclosed within this report for the location and delineation of the project site. DOWNSTREAM DRAINAGE CONSIDERATION Please refer to the enclosed aerial topography map for the mapping of the downstream conveyance system. Storm drainage runoff from the two existing catch basins along the north portion of Sunset Boulevard discharges to Honey Creek in two different routes. The existing catch basin located at the east portion of the project crosses Sunset Boulevard via an existing a 18-inch CMP pipe to the catch basin located at the south portion of the road and discharges to the south vi an 18-inch CMP pipe. From here, storm drainage runoff sheetflows for approximately 150 feet before discharging into Honey • 4168.002 -2- AS/mh Creek. From this point, Honey Creek flows westerly through a wooded area and for approximately is600 feet before reaching an existing 72" x 44" arch culvert under 138th Avenue S. At this point the second catch basin located at the west portion of the project discharges to Honey Creek. The second catch basin which is located at the west portion of the project along Sunset Boulevard is tightlined to a 12-inch pipe which travels for approximately 400 feet before reaching the intersection of Sunset Boulevard and 138th Avenue S.E. From here, storm drainage runoff changes direction and travels southerly for approximately 200 feet through a 12-inch CMP pipe and discharges to the entrance of a 72" x 44" arch culvert under 138th Avenue S.E. As mentioned above, this is the location that the storm drainage runoff from two existing catch basins adjacent to the property meet each other. From this point, storm drainage runoff traveling southwesterly under an existing shopping center through a 72" x 44" arch culvert for approximately 900 feet before discharging to an open ditch located at the southwest portion of an existing McDonald's restaurant. This ditch is approximately 3 feet wide at the bottom and 10 feet wide at the top and approximately 2 to 3 feet deep. Storm drainage runoff travels approximately 200 feet before reaching the Whitman Avenue and discharging to two 56" x 36" culverts and traveling westerly for approximately 500 feet before crossing Sunset Boulevard. Through our research and conversation with the City official, we did not find that there were any indications of erosion or flooding along this drainage course. 4168.002 -3- AS/mh DISCUSSION AND ANALYSIS OF CORE REQUIREMENTS AND SPECIAL REQUIREMENTS The following is a brief discussion of how the project has or will comply with the seven core requirements and the twelve special requirements of the 1990 King County Drainage Manual. CORE REQUIREMENTS 1. Drainage at the Natural Location The proposed project will be designed to incorporate an on-site detention system for storm drainage runoff. The existing catch basin with an 18-inch CMP pipe is located adjacent to the project and is currently the natural discharge point for the project. During the design of the final grading, surface water runoff will be designed to discharge at this location. 2. Off-Site Analysis As required by Core Requirement No. 2, the upstream tributary drainage area has been identified and the Level I Drainage Analysis has been completed to identify an downstream drainage problems noted during the field investigation. The Level I Drainage Analysis is enclosed in the report and satisfied Core Requirement No. 2. 3. Runoff Control As required by Core Requirement No. 3, the proposed storm drainage system will provide the • required runoff control to limit the develop condition's peak rate of runoff to the predeveloped rate. 4. Conveyance System Core Requirement No. 4 states that all conveyance systems for the proposed project must be analyzed, designed and constructed for existing tributary off-site runoff and developed on-site runoff from the proposed project. During final design plan preparation of the project, a detailed sizing of the conveyance system will be completed which incorporates any tributary runoff area. Our field investigation has verified that the site does not receive surface water runoff from the upstream tributary area, therefore the conveyance system will only be designed to incorporate surface water runoff from the project site. A complete design and analysis of the final conveyance system will be completed during the final design plan preparation. 5. Erosion/Sedimentation Control Plan As part of the preparation of the final design plan an erosion/sedimentation control plan will be prepared in accordance with the King County Drainage Manual and/or City of Renton requirements. This plan will generally consist of a temporary erosion/sedimentation control pond, a construction entrance, mirafi filter fabric, temporary interceptor ditches and an outlet control structure sized in accordance with the design requirements. Core Requirement No. 5 will be satisfied through preparation of final design plans. 4168.002 4- AS/mh • 6. Maintenance and Operation Core Requirement No. 6 states that maintenance of all drainage facilities constructed or modified by a proposed project is the responsibility of the property owner except that the City may assume maintenance of drainage facilities constructed for formal plat subdivisions and some short plat subdivisions two years after construction approval. As part of the final preparation of the drainage report, a maintenance and operation manual will be prepared to identify maintenance requirements for the system as well as the schedule. No other specific action is needed at this time to satisfy this condition. 7. Bonds and Liability As indicated by Core Requirement No. 7, the drainage facility will be constructed in conformance with the bond and liability requirements of King County Code 9.04.100. No specific action is required at this time for this requirement. SPECIAL REQUIREMENTS 1. Special Requirement No. 1. Special Requirement No. I indicates that King County/City of Renton provide the authority to establish critical drainage areas within which any proposed projects must comply with these special requirements. The proposed project is located within the City of Renton and on-site detention standard is required. The special requirements for drainage control within this basin will be incorporated into the final design plans for the project. • 2. Special Requirement No. 2 - Compliance With an Existing Master Drainage Plan - Special Requirement No. 2 indicates that if a proposed project lies within an area covered by an approved master drainage plan as listed at the BALD Division Permit Center, then the proposed project's drainage review and engineering design plans must be prepared in accordance with any special requirements of the master drainage plan. The proposed project does not lie within an existing master drainage plan area. No other specific action is required at this time to satisfy this condition. 3. Special Requirement No. 3. Special Requirement No. 3 contains a list of conditions which require a master drainage plan. This requirement is not applicable to the proposed project because the project is not a master drainage development; the project does not encompass a contiguous sub-basin of more than 200 acres; the project is not a commercial building permit or planned unit development that will eventually construct more than 50 acres of impervious surface area; and the project will not clear an area more than 500 acres within a contiguous drainage sub-basin. Therefore Special Requirement No. 3 is not applicable to this project. 4. Special Requirement No. 4. Special Requirement No. 4 states that a proposed project lying within an adopted basin or community plan must prepare engineering plans in conformance with the special requirements of the adopted basin plan or community plan. As stated in Special Requirement No. 1, the project does not lie within any adopted basin or community plan. Therefore special Requirement No 4 is not applicable to this requirement 4168.002 -5- AS/mh 5. Special Requirement No. 5 - Special Water Quality Control. Special Requirement No. 5 states that if a proposed project will construct more than one acre of impervious surface that will be subject to vehicular use or storage of chemicals and proposes a direct discharge of runoff to a regional facility, receiving water, lake, wetland or closed depression without on-site peak rate runoff control or the runoff from the project will discharge into a Type I or Type II stream or Type I1 wetland within one mile from the project site, that a wetpond meeting the standards described in the King County Drainage Manual shall be employed to treat a project's runoff prior to discharge from the site. Since the proposed project will not create impervious surface area, exceeding one acre, which is subject to vehicular use, Special Requirement No. 5 is not applicable to this project. 6. Special Requirement No. 6 - Coalescing Plate Oil/Water Separators. Special Requirement No. 6 indicates that if a proposed project will construct more than five acres of impervious surface that will be subject to petroleum storage or transfer or high vehicular use, which exceeds 2,500 vehicle trips per day, or heavy equipment use storage or maintenance, then a coalescing plate oil/water separator or the equivalent shall be incorporated to treat the project's runoff prior to treatment by the wetpond, wet vault or water quality swale. Since the project does not meet the threshold conditions indicated in this requirement, Special Requirement No. 6 is not applicable to this project. 7. Special Requirement No. 7 - Closed Depression. Special Requirement No. 7 indicates that if a proposed project will discharge runoff into an existing closed depression that has greater than 5,000 square feet of surface area at potential overflow, the project must meet the special requirements indicated by this condition. The proposed project does not discharge surface • water runoff into closed depression area based on a review of the existing topographic survey, and therefore. Special Requirement No. 7 is not applicable to this project. 8. Special Requirement No. 8. Special Requirement No. 8 states that if a project proposes to use a lake, wetland or closed depression for peak rate runoff control consistent with Core Requirement No. 3, then the project must meet the special requirements for this condition. Since the project does not propose to use a lake, wetland, or closed depression for peak rate runoff control, Special Requirement No. 8 is not applicable to the project. 9. Special Requirement No. 9 - Delineation of 100-year Flood Plain. Special Requirement No. 9 states that if a proposed project contains or abuts a stream, lake, wetland or closed depression or if other King County regulations require study of flood hazards, then the 100-year flood plain boundaries, based on an approved flood hazard study as described below shall be delineated on the site improvement plans and profiles and on any final subdivision maps prepared for the project. The proposed project does not contain or abut a stream, lake, wetland or closed depression, and therefore, Special Requirement No. 9 is not applicable to this project. 10. Special Requirement No. 10 - Flood Protection Facilities for Type I and Type II Streams. Special Requirement No. 10 states that if a proposed project contains or abuts a type I or type 1I stream that has an existing flood protection facility such as a levy, revetment and berms or proposes to construct a new or modify an existing flood protection facility, then the flood protection facilities shall be analyzed and or designed as described in the conditions to demonstrate conformance with the Federal Emergency Management Administration. Since the • project does not abut a Type I or Type II stream and is not adjacent to a flood protection facility such as a levy revetment and/or berm, Special Requirement No. 10 is not applicable to this project. 4168.002 -6- AS/mh 11. Special Requirement No 11 - Geotechnical Analysis and Report. Special Requirement No. 11 states that if a project proposes to construct a pond or an infiltration system (excluding roof downspout or dispersion system): (a) within 200 feet of the top of a steep slope or; (b) on a slope with a gradient steeper than 15 percent or; (c) using a berm higher than 6 feet or proposes to modify an existing flood protection facility, then a geotechnical analysis and report shall be prepared and stamped by a geotechnical professional civil engineer that shall address, at a minimum, the analysis described within this condition. Since this project does not meet the threshold requirements of Conditions A B and C. Special Requirement No. 11 is not applicable to this project. 12. Special Requirement No. 12 - Soils Analysis and Report. Special Requirement No. 12 states that if the soils underlying a proposed project have not been mapped or if the existing soils maps are in error or are not of sufficient resolution to allow a proper engineering analysis of the proposed site to be performed, then a soils analysis and report shall be prepared and stamped by a professional civil engineer with expertise in soils to verify and/or map the underlying soils by addressing the minimum as described in this condition. The King County SCS Soils Survey Maps indicate that the existing soils within the proposed project consist of Alderwood sandy gravelly sandy loam soils. Since the project does not meet the threshhold requirement to identify the soils bearing, Special Requirement No. 12 is not applicable to this project, although we anticipate that a geotechnical report will be prepared during the final design of the project and footing design of the building. • 4168.002 -7- AS/mh PRELIMANARY STORM DRAINAGE DETENTION CALCULATION BIVO. 10 re fie ve/o oer/ J W W W moo , " 6'fou w.od, Yo.� Saco d "v vaa 11 rrr giosr'l .W CI" re 2.o Poo 300 , �= 0 P05 L Developed Coy, 7o TG/ 7�n)c)P,- viotA,5 N. ✓fa = I,qS � � �N� 7 -r n 1 r I f 4/22/91 Barghausen Engineers page 1 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR. STORM --------------------------------------------------------------------- --------------------------------------------------------------------- DETAIL BASIN SUMMARY BASIN ID: IA NAME: 2YR/24HR PRE-DEV. RUNOFF SOS METHODOLOGY TOTAL AREA. . . . . . . : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE, . . , : USER1 PERVIOUS AREA PRECIPITATION, , , . : 2.00 inches AREA. : : 3.20 Acres TIME INTERVAL. . . . : 10.00 min CN, , , , : 61 .00 TIME OF CONC. . . . . : 42.93 min IMPERVIOUS AREA ABSTRACTION COEFF: 0,20 AREA. . : 0.00 Acres ON. . . . 98.00 TcReach - Sheet L : 300.00 n5:0.4000 p2yr: 2.00 5:0.0850 TcReach - Shallow L: 100.00 k.s:5.00 s:0.0250 PEAK RATE: 0.26 cfs VOL: 0. 16 Ac-ft TIME: 490 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DESI RUNOFF RUNOFF RUNOFF RUNG (min ) (cfs ) (min ) (cfs ) (min ? (cfs ) (.min ) (cf 10 3S@ 690 @. 1.251 1030 0.09 20 380 700 0. 12S2 1040 0.09 30 370 710 0. 1259 1050 0.08 40 380 720 0. 1268 1060 0.08 S0 390 0.0004 ?30 0. 1280 1070 0.08 60 400 0.0019 740 0. 1292 1080 0.06 70 410 d.0057 750 0. 1305 1090 0.08 80 420 0.0122 760 0. 1315 1100 0.08 90 430 0.0210 770 0. 1297 1110 0.08 100 440 0.0328 780 0. 1242 1120 0.08 110 450 0.0494 790 0. 1161 1130 0.08 120 460 0.0806 800 0. 1141 1140 0.06 130 470 0- 1486 0l@ 0. 1123 1150 0.09 140 480 0.2304 820 0. 1116 1160 0.09 150 490 @,2642 830 0. 1115 1170 0.09 160 500 0.2479 840 0. 1118 1180 0.09 170 510 0.2153 850 0. 1123 1190 0.09 180 520 0. 1940 860 0, 1129 1200 0.09 19d 530 0. 1775 870 0. 1135 1210 0.09 200 540 0. 1596 680 0. 1141 1220 0.09 210 550 0. 1439 890 0. 11:_?.--'� 1230 0.09 220 560 0. 1343 =00i 0. 1105 1240 0.09 230 570 0. 1301 9110 0, 1075 11250 0.09 240 _-80 0. 1289 =2d 0, 1056 1260 0.09 250 590 0, 1295 30i @, 1@4r 1270 0y,@9 260 600 0. 1308 _4d 0, 104:, 12r0 0,OR 270 610 0. 1323 950 0. 1047 1290 0.09 280 620 0, 1343 56@ 0. 1050 1300 0.09 290 6:_10 0. 1365 970 0, 1054 1310 0:09 300 640 0, 1385 80 0. 1058 1:_,20 0,09 310 650 0. 1379 _90 0,. 1083 1.7_ @ 0,09 320 660 0. 1'3? O00 0, 1c)SS 1:_,40 0,09 670 0, 1290 1 '-10 0. 1046 1350 0,09 340 680 0, i260 „ 0 0. 1000 1360 0,09 4/22/91 Barghausen Engineers page 2 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM DETAIL BASIN SUMMARY BASIN ID: 2A NAME: 10YR/24HR. PRE-DEV. RUNOFF SCS METHODOLOGY TOTAL AREA. . . . , . , : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2.90 inches AREA. . : 3.20 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 .00 TIME OF CONC. . . . . : 42.93 min IMPERVIOUS AREA ABSTRACTION COEFF: &20 AREA. . : 0.00 Acres CN. , , , 96.00 TcRea.ch. - Sheet L: 300,00 ns:0.4000 p2yr: 2.00 s:0.0650 TcReach - Shallow L: 100.00 ks:5.00 s:0.0250 PEAK. RATE: 0.69 cfs VOL: 0.33 Ac-ft TIME: 490 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DESI RUNOFF RUNOFF RUNOFF RUNG (min ) (cfs ) (min ) (cfs ) (min) (cfs ) (min ) (cf ------------------------------------------------------------------ ------------------------------------------------------------------ 10 350 0.0239 690 0.2476 1030 0: 17 20 360 0.0337 700 0.2466 1040 0. 16 30 370 0.0444 710 0.2469 1050 0. 16 40 380 0.0551 720 0.2476 1060 0. 16 50 390 0.0655 730 0.2490 1070 0. 16 60 400 0.0762 740 0.2505 1080 0. 15 70 410 0.0911 750 0.2520 1090 0. 15 80 420 0. 1127 760 0.2530 1100 0. 15 90 430 0. 1374 770 0.2489 i110 0. 16 100 440 0, 1676 780 0.2376 1120 0. 16 110 450 0.2084 790 0.2253 1i30 0. 16 120 460 0.28S5 800 0.2170 1140 0. 16 130 470 0.4503 810 0.2130 1150 0. 16 140 480 0.6349 820 0.2111 1160 0. 16 150 490 0.6895 830 0.210S 1170 0. 16 160 500 0.6213 840 0.2105 1180 0, 16 170 510 0.5211 850 0.2109 1190 0. 16 180 520 0.4551 860 0.2115 1200 0. 16 190 530 0.4059 870 0.2122 1210 0. 16 200 540 0.3579 880 0.2126 1220 0. 16 210 550 0.3174 690 0.210E 1230 0. 16 220 560 0.2919 900 0.205i 1240 0. 16 230 570 0.2794 910 & 1994 1250 0. 16 240 560 0.2737 920 0. 1954 1260 0. 1E 250 590 0.2724 930 0. 1936 1270 0. 15 280 600 0.2729 940 0. 1926 1280 0. 16 270 610 0.2738 950 0, 1926 1290 0. 16 280 620 0.2760 960 0. 1928 1500 0, 16 290 630 0.2787 970 & 1932 1310 0. 16 300 0.0001 640 0.2810 960 0. 19.?7 1.320 0. 16 310 0.0010 650 0.2782 990 0. 1942 1330 0. 1.6 320 0.00.39 660 0.2683 1000 0. 1944 1.340 0. 16 :_307� 0,0069 670 0.2575 1010 0. 1909 1150 0. 16 34n 0.0156 680 0..250S 1 020 O. 1 t_20 1360 & 16 4/22/91 Barghausen Engineers page 3 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM DETAIL BASIN SUMMARY BASIN ID: 3A NAME: 100YR/24HR.. PRE-DEV. RUNOFF SCS METHODOLOGY TOTAL AREA. . . . . . . : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3.90 inches AREA- : 3.20 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 61 .00 TIME OF CONC. . . . . : 41.93 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 0.00 Acres CN. . . . 98.00 TcReach - Sheet L: 300.00 n5:0.4000 p2yr: 2.00 s:0.0650 TcReach - Shallow L: 100.00 k.s:5.00 s:0.0250 PEAK: RATE: 1 .25 cfs VOL: 0.S4 Ac-ft TIME: 490 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DESI RUNOFF RUNOFF RUNOFF RUNG (min ) (cfs ) (min ) (cfs ) (min ) (cfs ) (min ) (cf ------------------------------------------------------------------ ------------------------------------------------------------------ 10 350 0. li l ?- 690 0.3939 1030 0.26 20 360 0. 1295 700 0.391S 1040 0.25 30 370 0. 1485 710 0.3911 1050 0.24 40 380 0. 1664 720 0.3916 1060 0.24 50 390 0. 1825 730 0.3928 1070 0.24 60 400 0. 1988 740 0.3943 1080 0.24 70 410 0.2241 7SO 0.3959 1090 0.24 80 420 0.2632 760 0.3968 1100 0.24 90 430 0.3076 770 0.3896 1110 0.24 100 440 0.3604 780 0.3712 1120 0.24 110 450 0.4319 790 0.351E 1130 0.24 120 460 0.5677 800 0.3381 1140 0.24 130 470 0.8565 810 0.3313 1150 0.24 140 480 1 . 1698 820 0.3279 1160 0.24 150 490 1 .2451 830 0.3264 1170 0.24 ISO 500 1 . 1041 640 0.3260 1180 0.24 170 510 0.9128 850 0.3262 1190 0.24 180 520 0.7668 860 0.3267 1200 0.24 190 530 0.6939 870 0.3275 1210 0.24 200 540 0.6062 880 0.3279 1220 0.24 210 5SO 0.5335 890 0..3245 12.330 0.24 220 560 0.4872 900 0.31.5E 1240 @.24 230 570 0.46 .4 910 0.3062 1250 0.24 240 580 0.45i6 920 @.2998 1260 0.24 2SO 0.0007 590 @.4474 930 0.2967 1, 0.24 260 0.0034 600 0.4463 940 0.2952 1280 0.24 270 0.0089 610 0.4460 950 0.2946 1290 0.24 280 0.0171 620 0.4479 960 0.2946 1300 0.24 _94'_. tr,_027E :0 0.4508 1@, @.246 300 0,,0404 640 0.4530 Ko 0.295.' 132t�i 0.24 310 0_@544 65@ 0.4472 990 0.2y5Y 1:_-30 0."24 20 0.0685 660 0.4302 1000 0.2958 1340 0.24 330 0.0 670 0,41119 1 01 0 0.2190C. 1 7E;0 0.24 340 0.C' 58 680 0,39g5 102 0,276: 1360 0, 4 4/22/91 Barghausen Engineers page 4 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM DETAIL BASIN SUMMARY BASIN ID: 4A NAME: 2YR/24HR POST-DEV.RUNOFF SCS METHODOLOGY TOTAL AREA. . . . . . . : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2.00 inches AREA- : 1 .22 Acres TIME INTERVAL. . . . : 10.00 min ON. . . . : 86.00 TIME OF CONC. . . . . : 5.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA- : 1 .96 Acres ON- . : 98.00 TcReach - Channel L: 300.00 kc:21 .00 5:0.0600 PEAK. RATE: 1 .51 cfs VOL: 0.36 Ac-ft TIME: 460 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DESI RUNOFF RUNOFF RUNOFF RUNO (min ) ( cfs ) (min ) (cfs ) (min ) (cfs ) (min ) (cf 10 350 0. 1810 690 0.2392 1030 0. 13 20 360 0. 1880 700 0.2399 1040 0. 13 30 370 0. 1946 710 0.2405 1050 0. 14 40 380 0.2009 720 0.2410 1000 0. 14 50 390 0.2068 730 0.2416 1070 0. 14 60 400 0.2990 740 0.2422 1080 0. 14 70 410 0.3117 750 0.2427 1090 0. 14 80 420 0.3214 760 0. 1939 1100 0. 14 90 430 0.4429 770 0. 1928 1110 0. 14 100 440 0.4608 780 0. 1932 1120 0. 14 110 450 0.6962 790 0. 1935 1130 0. 14 120 460 1 .5101 800 0. 1938 1140 0. 14 130 470 0.8141 810 0. 1941 1150 0. 14 140 480 O.S459 820 0. 1944 11GO 0. 1.4 150 490 0.4096 830 0. 1947 1170 0. 14 160 0.0038 500 0.4098 840 0. 1950 1180 0. 14 170 &0113 510 0.4135 850 0. 1953 1190 0. 14 180 0.0185 520 0.2774 860 0. 1956 1200 0. 14 190 0.0253 530 0.2750 870 0. 1958 1210 0. 14 200 0.0319 540 0.2764 880 0. 1727 1220 0. 14 210 0.0381 550 0.2778 890 0. 1722 1230 0. 14. 220 0.0518 560 0.2791 900 0. 1724 1240 0. 14 230 0.0596 570 0.2804 910 0. 1726 1250 0. 14 240 0.0668 580 0.2817 920 0. 1728 1260 0. 14 250 0.0737 590 0.2829 930 0. 1730 1270 0. 14 260 0.0803 600 0.2841 940 0. 1732 1280 0. 14 270 0.0865 610 0.2853 950 0. 1734 1290 0. 14 260 0. 1085 620 0.2864 960 0. 1736 1300 0. 14 290 0. 1166 630 0.2875 970 0. 1738 1310 0. 14 300 0. 1238 640 0.2374 980 0. 1740 1320 0. 14 10 0. 1307 650 0.2367 990 0. 1741 13.30 0. 14 320 0. 1372 660 0.2373 WOO 0. 1404 1 340 0. 1 4 330 0. 1434 670 0.2380 1010 0. 1395 1350 0. 14 340 0. 1729 680 0.2386 1020 0. 1397 1360.E 0. 14 4/22/91 Barghausen Engineers page 5 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR./10YR/100YR/24HR STORM --------------------------------------------------------------------- DETAIL BASIN SUMMARY BASIN 10: 5A NAME: 10YR/24HR. POST-DEV. RUNOFF SCS METHODOLOGY TOTAL AREA. . . . . . . : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2.90 inches AREA. . : 1 .22 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 86.00 TIME OF CONC. . . . . : 5.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA- : 1 .98 Acres CN. . . . : 98.00 TcRea.ch - Channel 1-: 300.00 kc:21 .00 s:0.0600 PEAK: RATE: 2.49 cfs VOL: 0.59 Ac-ft TIME: 460 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DE=>I RUNOFF RUNOFF RUNOFF RUNO (min ) ( cfs ) (min ) ( cfs ) (min ) (cfs ) (min ) (cf ------------------------------------------------------------------ ------------------------------------------------------------------ 10 350 0.3433 690 0.3713 1030 0.21 20 360 0.3519 700 0.3718 1040 0.21 30 370 0.3599 710 0.3724 1050 0.21 40 380 0.3675 720 0.3729 1060 0.21 50 390 0.3745 730 0.3734 1070 0.21 60 400 0.5354 740 0.3739 1080 0.21 70 410 0.5516 750 0.3744 1090 0.21 80 420 0.5627 760 0.2989 1100 0.21 90 430 0.7666 770 0.2971 1110 0.21 100 440 0.7884 780 0.2974 1120 0.21 110 0.0002 450 1 .510.3 790 0.2977 1130 0.21 120 0.0094 460 2.4933 800 0.2979 1140 0.21 130 0.0201 470 1 .3254 810 0.2982 1150 0.21 140 0.0302 480 0.8824 820 0.2985 1160 0.21 150 0.0397 490 0.6591 830 0.2988 1170 0.21 160 0.0593 500 0.6569 840 0.2990 1180 0.21 170 0.0716 510 0.6606 850 0.2993 1190 0.21 180 0.0828 520 0.4419 860 0.2995 1200 0.21 190 0.0934 530 0.4371 870 0.2998 1210 0.21 200 0. 1034 540 0.4385 880 0.2642 1220 0.21 210 0. 1127 550 0.4399 690 0.2633 1230 0.21 220 0. 1421 560 0.4412 900 0.2635 1240 0.21 230 0. 15.38 570 0.4424 910 0.2637 1250 0.21 240 0. 1643 580 0.4437 920 0.2639 1260 0.21 250 0. 1740 590 0.4448 930 0.2641 1270 0.21 280 0. 1832 600 0.4460 940 0.2642 1280 0.21 270 0. 1918 610 0.4470 950 0.2644 1290 0.21 280 0.2341 620 0.4481 960 0.2646 1300 0.21 290 0.2453 630 0.4491 970 0.2647 1310 0:21 300 0.2550 640 0.3704 980 0.2649 1320 0.21 10 0.2640 650 0.3668 990 0.2651 1330 0.21 320 0.2724 660 0.3695 1000 0.2136 1340 0.21 330 0.2803 670 0.3701 1010 0.2123 1.350 0.21 340 0.3328 680 0.3707 1020 0.2124 1360 0.21 4/22/91 Barghau5en Engineers page 6 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM DETAIL BASIN SUMMARY BASIN ID: 66 NAME: 100YR/24HR.POST-DEV. RUNOFF SCS METHODOLOGY TOTAL AREA. . . . . . . : 3.20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION- . : 3.90 inches AREA. . : 1 .22 Acre TIME INTERNAL. . . . : 10.00 min CN. . . . : 86.00 TIME OF CONC. . . . . : 5.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 1. .98 Acres CN. . . . 98.00 TcReach - Channel_. L: 300.00 kc:21 .00 s:0.0600 PEAK RATE: 3.59 cfs VOL: 0.85 Ac-ff TIME: 460 min r TIME DESIGN TIME DESIGN TIME DESIGN TIME DESI RUNOFF RUNOFF RUNOFF RUNG (min ) ( cfs ) (min ) ( cfs ) (min ) (cfs ) (min ) (cf ------------------------------------------------------------------ ------------------------------------------------------------------ 10 350 0.5339 690 0.5162 1030 0.29 20 360 0.5434 700 0.5167 1040 0.29 30 370 0.5521 710 0.5172 1050 0.29 40 380 0.5602 720 0.5177 1060 0.29 50 390 0.5677 730 0.5181 1070 0.29 60 400 0.8064 740 0.5186 1080 0.29 70 410 0.6254 750 0.5190 1090 0.29 80 420 0.8368 760 0.4142 1100 0.29 90 0.0069 430 1 . 1327 770 0.4115 1110 0.29 100 0.0262 440 1 . 1573 780 0.4117 1120 0.29 110 0.0444 450 2. 1982 790 0.4120 1130 0.29 120 0.0611 460 3.5871 800 0.4122 1140 0.29 130 0.0766 470 1 .8916 610 0.4125 1150 0.29 140 0.0910 480 1 .2544 820 0.4127 1160 0.29 150 0. 104.3 490 0.9346 830 0.4129 1170 0.29 160 0. 1411 500 0.9296 840 0.4132 1180 0.29 170 0. 1582 510 0.9330 850 0.4134 1190 0.29 180 0. 1735 520 0.6233 860 0.4136 1200 0.29 190 0. 1876 530 0.6158 870 0.4138 1210 0.29 200 0.2006 540 0.6171 880 0.3646 1220 0.29 210 0.2127 550 0.6183 890 0.36.34 1230 0.29 220 0.2615 560 0.6195 900 0.3635 1240 0.29 230 0.2766 570 0.6207 910 0.3637 1250 0.29 240 0.2896 580 0.6218 920 0.3638 1260 0.29 250 0.3016 590 0.6229 930 0.3640 1270 0.29 260 0.312_ 600 0.6239 940 0.3641 1280 0.29 270 0.3231 610 0.6249 950 0.3643 1290 0.29 280 0.3693 620 0.6258 960 0.3644 1300 0.29 290 0.4030 630 0.6268 970 0.3646 1310 0.29 300 0.4142 640 0.5166 980 0.3647 1320 0.29 W0 0. .245 650 0.5140 990 0.364,E 1330 0.29 320 0.4341 660 0.5146 1000 0.2940 1.340 0.29 330 0.4421 670 0.5151 iolo 0.2920 1Z50 0.29 340 0.5218 680 0.5157 1020 0.2921 1360 0.29 4/22/91 Barghausen Engineers page 7 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM HYDROGRAPH SUMMARY PEAK. TIME VOLUME HYD RUNOFF OF OF Ccntri6 NUM RATE PEAK: HYDRO Area cfs min. cf-AcFt Acres 1 0.264 490 7042 cf 3.20 2 0.690 490 14411 cf 3.20 3 1 .245 490 23736 cf 3.20 4 1 .510 460 15707 cf 3.20 5 2.493 460 25596 cf 3.20 6 3.587 460 36860 cf 3.20 7 0.264 640 15707 cf 3.20 8 0.689 SOO 25596 cf 3.20 • 4/22/91 Barghausen Engineers gage N.E. SUNSET BLVD. APT. COMPLEX. STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/124HR STORM STORAGE STRUCTURE LIST RECTANGULAR VAULT ID No. 1 Description: DETENTION Length: 100.00 ft . Width: 19.50 ft . • 4/22/91 Barghausen Engineers page 9 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM --------------------------------------------------------------------- --------------------------------------------------------------------- • STAGE STORAGE TABLE RECTANGULAR VAULT ID No. 1 Description: DETENTION Length: 100.00 ft . Width: 19.50 ft . STAGE <----STORAGE----:- STAGE <::----STORAGE---- STAGE ---STO ( ft ) ---cf--- --Ac-Ft- ( ft ) ---cf--- Ac-Ft- ( ft ) --cf--- ------------------------------------------------------------------- ------------------------------------------------------------------ 100.00 0.0000 0.0000 101 .30 2535 0.0582 102.60 507 100. 10 195.00 0.0045 101 .40 2730 0.0627 102.70 526 100.20 390.00 0.0090 101 .50 2925 0.0671 102.80 546 100.30 585.00 0.0134 101 .60 3120 0.0716 102.90 565 100.40 780.00 0.0179 101 .70 3315 0.0761 103.00 585 100.50 975.00 0.0224 101 .80 3510 0.0806 103. 10 604 100.60 1170 0.0269 101 .90 3705 0.0851 103.20 G24 100.70 1365 0.0313 102.00 3900 0.0895 103.30 643 100.80 1560 0.0358 102. 10 4095 0.0940 103.40 663 100.90 1755 0.0403 102.20 4290 0.0985 103.50 682 101 .00 1950 0.0448 102.30 4485 0. 1030 103.60 702 101 . 10 2145 0.0492 102.40 4680 0. 1074 103.70 721 101 .20 2340 0.0537 102.50 4875 0. 1119 103.80 741 • • 4/22/91 Barghausen Engineers page 10 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM SDISCHARGE STRUCTURE LIST MULTIPLE ORIFICE ID No. 1 Description: CONTROL STRUCTURE Outlet Elev: 100.00 Elev: 98.00 ft Orifice Diameter: 2.6695 in. Elev: 101 .90 ft Orifice 2 Diameter: Z.7500 in. • 4/22/91 Barghausen Engineers page 11 N.E. SUNSET BLVD. APT. COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM • STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 1 Description: CONTROL STRUCTURE Outlet Elev: 100.00 Elev: 98.00 ft Orifice Diameter: 2.6895 in. Elev: 101 .90 ft Orifice 2 Diameter: 3.7500 in. STAGE DISCHARGE---;- STAGE <--DISCHARGE---> STAGE 0-DISC ( ft ) ---cfs-- ------- ( fi ) ---cfs-- ------- ( ft ) ---cfs- 100.00 0.0000 101 .60 0.2483 103.20 0.786 100. 10 0.0621 101 .70 0.2559 103.30 0.808 100.20 0.0878 101 .80 0.2633 103' 40 0.829 100.30 0. 1075 101 .90 0.2706 103.50 0.849 100.40 0. 1241 102.00 0.3983 103.60 0.870 100.50 0. 1388 102. 10 0.4551 103.70 0.889 100.60 0. 1520 102.20 0.5002 103.80 0. 908 100.70 0. 1642 102.30 0.5390 103.90 0.927 100.60 0. 1756 102.40 0.5739 104.00 0. 945 100.90 0. 1862 102.50 0.6060 104. 10 0.963 101 .00 0. 1963 102.60 0.6358 104.20 0. 981 101 . 10 0.2059 102.70 0.6639 104.30 0.998 • 101 .20 0.2150 102.80 0.6905 104.40 1 .015 101 .30 0.2238 102.90 0.7159 104.50 1 .031 101 .40 0.2322 103.00 0.7402 104.60 1 .048 101 .50 0.2404 103. 10 0.7636 104.70 1 .064 4/22/91 Barghausen Engineers Rage 12 N.E. SUNSET BLVD. APT, COMPLEX STORM DRAINAGE DETENTION CALCULATION 2YR/10YR/100YR/24HR STORM LEVEL POOL TABLE SUMMARY MATCH INFLOW ST DI <:-PEAK-> STORAGE --------DESCRIPTION---------:- (cfs ) ( cfs ) id id <-STAGE> id VOL ( cf ) 2YR/24HR ROUTING . . . . . . . . . . . . . 0.26 1 .51 1 1 101 .81 7 3S 10YR/24HR ROUTING 0.69 2.49 1 1 102.80/ 8 S4F • • ---- - 407.2 FL S-kJITARY SEVER MANHOLE 07 OF RIM = 407.28 HOUSE HOUSE 412.0 407.0 HOUSE 412.4 407.3 1 / _ 418.7 z FENCE � 418 1 \ 21 F 14 F _' %/ r--STORM DRAINAGE CATCH BASIN / - IrF tf!"F _-_ trm \\_r Lc 6F 407.E T.G. = 406.09 24-F �- 21"F 12'F tiS :4'F 12'F. 1�F Y 14'F x 407/tt 1 420 J 1frF IrF 13'F 17) / 1Tf� i __ .� 1 24'F 5 STORM DRAINAGE CATCH BASIN V F "i E _--1 I ar F - _ _ / \1 �' �- T.G. = 405.79 d"f 6� 2ti F 20'F\�� 10'F �12" GRAVEL O / Z6'F / IVF' y 24 F 24F 2e'F • '►�' arF �F ►tv� DRIVE IrF gF Irf 20'F 2rF / 24-F SI'F � 14 i 12"F A 19rF 426.�`21Y\ 21'F A4 { 61F ^L 32'F Y$- - 2tfF 1 o"PL l a 4 dA \ A 2tF'F 24"F 20'F All }7F 18"F j / / `,�A( Iti F 6'S O 3-12"CU 21-F IF {` A d"S IS'F / j/ y ITF 1CC4 F\\ 428.8 2LrF Ir 4 act' 106.1 FL _FOUND 2- IRON PIPE FILLED IrH , 24-F 14 u WITH CONCRETE WITH BRASS O / / 24 i IruO gF 3rF / 2♦ F 25'F e PIN. IN CASE 20'F � O 2-16'F 1tT •J * t8"F 32'F 2�F/ / �} 3ai 411.b OIUNo 406.0 406.7 j kr�,0 TttF 10'F 1frF 10 F 26F Yi` PLANTER 7 26-F 267 441 15-M 24'F 2 F trF BOX / ��F \ 3�F i \ \�., 22'F 21rF F IVF 413.0 2t; Yet'` O 217F 24'F \ � 1rF 14'F 4 F ! �01/ 7--CONCRETE 2�F � � A 6F SLAB A'D 26`F ' 26-F � �,.\, �\5'F 14'F' 2CfFr * � 12`F 1�F ul trF t O STEPS 1 406-9 430. mn _ _ i _ 26'F ll FL 1- i• 2�F Y 2U F �F to F '1r F r*1 �F IF EL DRIVE `F �1 1` ib'F i6'F O, \ 1�F 6-u 3VF 410.1 cF �� 0 2rF 16"F io"F� \ 141P fiy FUEL ' `� 4'F 2 i � $F 24 F OIL % 71 I 1 f3 N ' t V. F 2frF 2drf I 'F TF 17e 20"17 24"F " FFIILLLER 24'F Z 2 LJ) {,j T6FA 14 F 24-F t4'F 'GrF O6 ?a'F !'Y1` \ 'T4'. CIO 14'F 406.0 406.7 '►�` 24'F e-F 1VA �-BARBWIRE �� 1cr6 1 F ZUF 24'F 24 F OC � 41 [ 67 t�F `��, 24.F FENCE 5' HIGH WOOD y , � p A frF 4 F et 9 � 4'i TE FENCE SF G 11rF 1b"F \OVERHANG-� 24'F ,� 406.2 S 1 4,F 11rF �trF 24F \ CARPORT STORM OFF i' ' 20 F 1 F `� 16F I0'F 2-1rF 21]'F \ \ 411.2 Q "' T.G. 4C 33'F IlrF F 1VA O 16 F 24F Zti F HOG E I VF 420.1 20-F 14F �.�\ FENCE - 5' HIGH WOOD rp FENCE ll f/ 21rF 2Ai F O 44 y I 14"i F 14'F Sri 14'F 16F 1 F, 4`j•0 1e"F 26'F 2rF ZOrF l- 41ti.8) i Y -CONCR E 1 T.G. DRAIN ItrF�I 1 trF 2�f F �A / 21rF y SIDEWA j �- .G. = 406.1 418.1 24F 26'F O 405.8 26'F TWIN 16'7 � fSA 1rF 26 F r trFl �Y 1(fA AND 24 F. F rF Ai IrF G�r STEPS 24'F Ifi F lEF � 16'F WOOD 24'F 0 Af 16'F A(y - 1 405 9 ttrF M I4 f 24,164 O ' Il�F ! SHED-�� 12-F it 00 -�_� FL TA ♦ 26'F 418 _�f 2U'F `; _�-5-15'F i' .Arc 12 F 24 F NCR 267 /- 3T F y��O ,'F �F ASPHALT 18'C �' Y �✓- r� 3S � { DRIVE WIN 24'F 127 0e I SHED 2W r 6F CHAIN LINK AND 24'F IdF - 4176.6 'fF SHIP LAP FEN `A� 1cF '1�F t -F 06.0 1CF - SAN(7 lfrF 2tiF i6 RIM�A 412.3 r z4b l3'F 5' HIGh n 1 0 ifrA CHAIN LINK 2F O 22F 1 ' FENCE T{F 06.2tfP 14c 411. 2CrF \ i ----- 413.8 -------- - -_ 41O f•L HOG / 418.3" 417. . ArF 1a1 F 41 0 1. (SD FENCEW IRE 414.9 18'F 415.2 \ 410.4 n n BUILDING CHAIN LINK O o. lfrF (A n BUILDING z z Z FEtJCE n �DECK _-�E -- --- - --- 1r /- EDGE OF GRASS - - mz k0MG PARKING LOT CONCRETE 1414.1 / SI:)EWALK �1.1 CHAIN CURB FeiICE SHED �'-'---.._ EXTRUUED ------------ -- ---- - /-HOGWIRE FENCE CONCRETE 417.9 CURB �� 409.5 A�c - - _ 415_5 408.7 0 \, 405.7 PATIO / �\ 406.5 1 r L �O FL. 1 HOUSE �OVEERHANG BUILDING � BV1w1P1G 1 a FUEL OIL Q -- - 417.7 WOODEPJ STRUCTURE ' BvI�p1NG -; FILLER CAP '� BUILDING ?'�1 406.2 o CC EXTRUDED 409.5 s r p�L y / CONCRETE 4C7.4 40i;.3 FL PARKING LOT --408.9 41Q 406.7 HOGWIRE 12" CONIC FL15.64 FL 12' CONC. p --�_ FENCE PIPE PIPE - \ 0 DRIVEWAY �AN O � � ,1...� - CONCRETE S10E iWALK C1 2 415.2 FL I CURB I __- - BREAK IN - - _ CUTOUT 414.3 FL _ CURB i 411.1 FL 00 r�7 r� �n o c� ---- ----- ----_ -__._ 415.0 -_ \4m.7 FL SCALE 1"=4 ' 413.9 o r' C,� ouvA(AVENUE S.E. - - 4-1 1.7 AVENUE U E�D N-E,� WSIT� T1�EA! AREA MAP