0+00 0+50 1+00 1+50 40 42 44 46 38 36 PROP. 149.91' - 8" Ø SDR 26 PVC PIPE @ 1.67% 0+00 EX. INV. OUT = 39.96' PROP. INV. IN= 40.20' EX. MODIFIED CURB INLET ST TOP= 42.69' 0+39.48 8" TEE W/ 4X8 REDUCER FOR UNDERDRAIN CONNECTION INV. = 40.82' 1+40.48 22.5° BEND & 4" CLEANOUT INV. = 42.23' 1+66.19 INV. OUT= 42.70' PROP. 18" PED RND GRATE INL PROP. 18" PVC MANHOLE NYLOPLAST OR EQUIV TOP= 45.00' 40 42 44 46 38 36 EX. CURB INLET ST5 TOP= 42.64' PROP. 16.28' - 15" Ø RCP @ 3.93% EX. INV. OUT = 38.62' EX./PROP. INV. IN= 39.32' 0+16.28 1+57.49 CONN. UNDERDRAIN 0+06.50 CONN. UNDERDRAIN REMOVE EX. 12" RCP CORE DRILL & GROUT 18" CONN. CORE DRILL & FLEXIBLE BOOT 2+00 0+02.50 CONN. UNDERDRAIN 0+07.70 CONN. UNDERDRAIN 0+03.75 45° BEND 0+17.50 CONN. UNDERDRAIN 0+87.58 CONN. UNDERDRAIN 1+34.98 CONN. UNDERDRAIN DUNCAN AVE. LESLIE AVE. YMCA PARKING LOT EX. CONCRETE WALK BENCH EX. 4' CONCRETE WALK EX. CONCRETE WALK 12" EX. FH 16" WV WV WV WV 26" 2" 6" 4" 4" 12" 6" 8" 4" 24" 4" 5" 3" 10" 12" 4" WM WM WM EX. GAS VALVE WM 10" 10" 10" 2" 36" 28" 18" 10" 6" 10" 5" 10" 10" 10" 30" 10" 18" 15" 10" 10" 12" 12" 24" 6" 6" 6" 6" 3" 3" 38" 6" 4" 4" SHRUB 10" 3" 4" 6" 3" 4" 4" 8" 10" 5" 6" 2X4" 6" 4" 8" 10" 6" 12" 6" 4" EX. IRRIGATION VALVE 5" 8" 6" 6" 6" 6" 10" 3" 5" 5" 12" 18" 16" WV WV 4" 12" 5" WV 6" 8" 4" 8" IPF 47 47 48 47 46 46 46 45 44 43 42 41 43 44 45 46 44 44 45 47 44 47 46 45 44 47 46 44 45 43 44 244.45' - EX. 10" SAN SWR @0.5% (CITY OF ALEXANDRIA) EX. SAN. MH TOP= 43.61' INV. IN (N)=32.65' INV. IN (E)=32.41 INV. OUT=32.41' 53' 21 EX. STM MH TOP= 42.44' INV. IN= 33.28' INV. OUT= 33.26' EX. STM MH ST2 TOP= 42.43' INV. IN (N)= 33.29' INV. IN (E)= 34.59' INV. OUT= 33.17' ET ST4 42.64' 39.32' 38.62' 16.28' - EX. 12" RCP STM SWR @ 3.93% STM SWR @0.36% (CITY OF ALEXANDRIA) 1 3.89' 2.81' .85' EX. TENNIS COURTS EX. BO SHRUB SHRUB 45 EX. WATER METER EX. IRRIGATON BOX EX. BASEBALL FIELD EX. ELEC. MH EX. STADIUM LIGHT EX. SCOREBOARD EX. CHAINLINK FENCE EX. 3' CHAINLINK FENCE EX. GAS VALVE 23.28' - EX. 27" RCP STM SWR @ -0.1% (CITY) 31.90' - EX. 12" RCP STM SWR @ 12.63% (CITY) EX. UTILITY BOW LID TOP= 45.60' EX. NO PARKING SIGN EX. MH TOP= 45.08' EX IRRIGATION CNTRL EX. ELEC. BOX EX. STADIUM LIGHT EX. TIMBER RETAINING WALL EX. STADIUM LIGHT EX. ELEC. BOX EX. ADA RAMP EX. ADA RAMP EX. ADA RAMP EX. IRRIGATION VALVE APPROX. LOC. EX. 12" WATER MAIN (VA AM WATER) EX. CURB INLET ST5 TOP= 42.69' INV. OUT= 39.96' EX. WOODCHIP PLAY AREA APPROX. LOC EX. GAS LINE (WASH GAS) 46 45 46 47 45 46 47 +42.29 +42.51 +43.01 +43.03 +43.31 43.66 + +43.94 +44.10 +44.52 47 47 +47.04 46 BM#1 SAN MH TOP= 43.61' #2 SAN MH P= 40.51' PROP. BMP SIGN PROP. BMP SIGN PROP. BMP SIGN C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O C/O PROP. WATER FOUNTAIN DRYWELL SEE DETAIL 3 ON SHEET L-508 PROP. 9' 3" SDR 26 PVC PIPE CONN. UNDERDRAIN TO 8" PIPE C/O PROP. BMP SIGN C/O DUNCAN AVE. LESLIE AVE. BENCH 12" EX. FH 16" WV WV WV WV 26" 2" 6" 4" 4" 12" 6" 8" 4" 24" 4" 5" 3" 12" 4" WM WM WM EX. GAS VALVE WM 10" 10" 2" 36" 28" 18" 10" 6" 10" 5" 10" 10" 10" 30" 10" 18" 24" 6" 6" 6" 6" 3" 3" 38" 6" 4" 4" SHRUB 10" 3" 4" 6" 3" 4" 4" 8" 10" 5" 6" 2X4" 6" 4" 8" 10" 6" 12" 6" 4" EX. IRRIGATION VALVE 5" 8" 6" 6" 6" 6" 10" 3" 5" 5" 12" 18" 16" WV WV 4" 12" 5" WV 6" 8" 4" 8" 47 48 47 46 46 45 44 43 42 41 43 44 45 46 44 44 45 47 44 47 46 45 44 47 46 44 45 43 44 244.45' - EX. 10" SAN SWR @0.5% (CITY OF ALEXANDRIA) EX. SAN. MH TOP= 43.61' INV. IN (N)=32.65' INV. IN (E)=32.41 INV. OUT=32.41' 1.53' 1.21 .06' EX. STM MH TOP= 42.44' INV. IN= 33.28' INV. OUT= 33.26' EX. STM MH ST2 TOP= 42.43' INV. IN (N)= 33.29' INV. IN (E)= 34.59' INV. OUT= 33.17' NLET ST4 = 42.64' = 39.32' = 38.62' 16.28' - EX. 12" RCP STM SWR @ 3.93% 7" STM SWR @0.36% (CITY OF ALEXANDRIA) ST1 = 33.89' 32.81' 32.85' E SHRUB SHRUB 45 EX. WATER METER EX. BASEBALL FIELD EX. GAS VALVE 23.28' - EX. 27" RCP STM SWR @ -0.1% (CITY) 31.90' - EX. 12" RCP STM SWR @ 12.63% (CITY) EX. IRRIGATION VALVE APPROX. LOC. EX. 12" WATER MAIN (VA AM WATER) EX. CURB INLET ST5 TOP= 42.69' INV. OUT= 39.96' EX. WOODCHIP PLAY AREA APPROX. LOC EX. GAS LINE (WASH GAS) +42.29 +42.51 +43.01 +43.03 +43.31 43.66 + +43.94 +44.10 +44.52 +47.04 BM#1 SAN MH TOP= 43.61' M#2 SAN MH TOP= 40.51' PROP. BMP SIGN PROP. BMP SIGN PROP. BMP SIGN PROP. WATER FOUNTAIN DRYWELL SEE DETAIL 3 ON SHEET L-508 PROP. 9' 3" SDR 26 PVC PIPE CONN. UNDERDRAIN TO 8" PIPE PROP. BMP SIGN DUNCAN AVE. LESLIE AVE. YMCA PARKING LOT EX. CONCRETE WALK BENCH EX. 4' CONCRETE WALK EX. CONCRETE WALK 12" 16" 26" 2" 6" 4" 4" 12" 6" 4" 24" 3" EX. GAS VALVE 2" 36" 28" 18" 10" 6" 10" 5" 10" 10" 10" 30" 10" 18" 24" 6" 6" 6" 6" 3" 3" 38" 6" 4" 4" SHRUB 10" 3" 4" 6" 3" 4" 4" 8" 10" 5" 6" 2X4" 6" 4" 8" 10" 6" 12" 6" 4" 5" 8" 6" 6" 10" 3" 5" 5" 12" 18" 16" 4" 12" 5" 6" 8" 4" 8" IPF 45 44 43 42 43 44 45 44 45 47 44 47 46 45 44 47 46 44 45 43 44 244.45' - EX. 10" SAN SWR @0.5% (CITY OF ALEXANDRIA) EX. SAN. MH TOP= 43.61' INV. IN (N)=32.65' INV. IN (E)=32.41 INV. OUT=32.41' EX. STM MH TOP= 42.44' INV. IN= 33.28' INV. OUT= 33.26' EX. STM MH ST2 TOP= 42.43' INV. IN (N)= 33.29' INV. IN (E)= 34.59' INV. OUT= 33.17' 16.28' - EX. 12" RCP STM SWR @ 3.93% % (CITY OF ALEXANDRIA) SHRUB SHRUB 45 EX. IRRIGATON BOX EX. BASEBALL FIELD EX. ELEC. MH EX. STADIUM LIGHT EX. SCOREBOARD EX. CHAINLINK FENCE EX. 3' CHAINLINK FENCE EX. GAS VALVE 23.28' - EX. 27" RCP STM SWR @ -0.1% (CITY) 31.90' - EX. 12" RCP STM SWR @ 12.63% (CITY) EX. UTILITY BOW LID TOP= 45.60' EX. NO PARKING SIGN EX. MH TOP= 45.08' EX IRRIGATION CNTRL EX. ELEC. BOX EX. STADIUM LIGHT EX. TIMBER RETAINING WALL EX. STADIUM LIGHT EX. ELEC. BOX EX. ADA RAMP EX. ADA RAMP EX. ADA RAMP X. CURB INLET ST5 TOP= 42.69' INV. OUT= 39.96' EX. WOODCHIP PLAY AREA APPROX. LOC EX. GAS LINE (WASH GAS) 46 45 46 47 45 46 47 +42.29 +42.51 +43.01 +43.03 +43.31 43.66 + +43.94 +44.10 +44.52 47 47 +47.04 46 BM#1 SAN MH TOP= 43.61' PROP. BMP SIGN PRO PROP. BMP SIGN PROP. WATER FOUNTAIN DRYWELL SEE DETAIL 3 ON SHEET L-508 PROP. 9' 3" SDR 26 PVC PIPE CONN. UNDERDRAIN TO 8" PIPE PROP. BMP SIGN SimpsonPlayground-baserevunderdraintocity_jl edits_CSedits_072618.dwg SOLICITATION NO.: FILE NAME: DWN BY: CKD BY: DESIGNED BY: DESCRIPTION D C A B MARK APPR. DATE: FILE NUMBER: SIZE: SUBMITTED BY: PLOT SCALE: PLOT DATE: DATE CONTRACT NO.: SHEET IDENTIFICATION CITY OF ALEXANDRIA VIRGINIA NOT FOR CONSTRUCTION SIMPSON PLAYGROUND + PASSIVE LAWN RENOVATION 421 E. MONROE AVENUE 05 JULY 2017 ANSI D LARDNER/KLEIN LANDSCAPE ARCHITECTS, PC 815 North Royal Street., Suite 200 Alexandria, Virginia 22314 703.739.0972 www.lardnerklein.com SHEET 11 OF 31 07/05/2017 ALEXANDRIA, VA 22301 KES L/KLA EBL L/KLA DOMINION SURVEYORS INC. 8808-H Pear Tree Village Court Alexandria, Virginia 22309 Phone: (703) 619-6555 Facsimile: (703) 799-6412 [email protected] Approved Date Director of Transportation and Environmental Services Director of Recreation, Parks and Cultural Activities Approved Date STORM SEWER PROFILE SCALE: 1" = 20' HORZ 1" = 2' VERT DRAINAGE AREA MAP - POST DEVELOPMENT SCALE: 1" = 40' D.A. TO PROP GRATE INLET A= 0.64 ACRES C= 0.30 Q2= 1.25 CFS Q10= 1.73 CFS D.A. TO ST5 A= 0.72 ACRES C= 0.37 Q2= 1.73 CFS Q10= 2.40 CFS D.A. TO CURB INLET ST4 A= 0.99 ACRES C= 0.48 Q2= 3.08 CFS Q10= 4.28 CFS D.A. TO STR #2 A= 1.58 ACRES C= 0.33 Q2= 3.39 CFS Q10= 4.69 CFS D.A. TO CURB INLET #1 A= 0.80 ACRES C= 0.56 Q2= 2.91 CFS Q10= 4.03 CFS DRAINAGE AREA MAP - PRE DEVELOPMENT SCALE: 1" = 40' SWM/BMP NARRATIVE THIS PROJECT PROPOSES THE RENOVATION OF A 1.17 ACRE PORTION OF SIMPSON PARK. THE EXISTING STONE DUST PATH WILL BE REMOVED, THE AREA REGRADED IN PLACES AND MULTIPLE DIFFERENT PLAY SURFACES WILL BE ADDDED. ALL THE SURFACES WILL BE PERVIOUS WITH A STONE BASE/UNDERDRAIN AS REQUIRED. A PERVIOUS PAVER WALK WILL BE USED AS A STRUCTURAL BMP TO MEET SWM REQUIREMENTS. THE SITE MEETS VRRM REQUIREMENTS BY REDUCING THE CN NUMBER FROM 82 IN THE PREDEVELOPED CONDITION TO 81 IN THE POST DEVELOPED CONDITION. USING THE RATIONAL METHOD, FOR THE STORM SEWER DESIGN, THE TEN YEAR RUNOFF TO THE THE EXISTING STORM SEWER IS REDUCED FROM 8.94 CFS TO 8.41 CFS. OUTFALL NARRATIVE THIS PROJECT PROPOSES THE RENOVATION OF A 1.17 ACRE PORTION OF SIMPSON PARK. THE EXISTING STONE DUST PATH WILL BE REMOVED, THE AREA REGRADED IN PLACES AND MULTIPLE DIFFERENT PLAY SURFACES WILL BE ADDED. THE PIPE BETWEEN STR 5 AND STR 4 IS NOT ADEQUATE IN THE EXISTING CONDITION AND SHALL BE REPLACED. THE PROJECT AREA DISCHARGES TO THE EXISTING STORM SEWER WITHIN DUNCAN AVE. 0.99 ACRES DRAINS TO DUNCAN AVE AND THEN ALONG THE GUTTER TO STORM STRUCTURE ST4. ST 4 DRAINS TO A MANHOLE THE CONNECTS TO A STORM SEWER WITH A SEWER SHED OF APPROXIMATELY 19 ACRES TO THE NORTH. ST2 CONNECTS DOWNSTREAM TO STR1 VIA A 27" PIPE. STR 1 RECEIVES RUNOFF FROM 0.5 ACRES TO THE NORTH AND THEN DISCHARGES 450' TO THE WEST THROUGH A 27" INCH PIPE WITH AN ASSUMED SLOPE EQUAL THAT OF THE PIPE BETWEEN STR 2 AND STR 1. THE RUNOFF FROM THE PARK HAS BEEN REDUCED. BY 0.53 CFS FOR A TEN YEAR STORM. THE EXISTING PIPE WAS ANALYZED FOR THE DOWNSTREAM 3 RUNS (150 FEET DOWNSTREAM OF THE STR2 WHICH SERVES A WATERSHED MORE THE 90% OF THE PROJECT WATERSHED. BASED UPON THE RECORD SOURCES AND THE SURVEY PERFORMED BY THE CITY OF ALEXANDRIA, IT IS MY OPINION THAT THE EXISTING STORM SEWER MEETS THE ADEQUATE OUTFALL REQUIREMENTS OF THE CITY OF ALEXANDRIA AND THIS PROJECT WILL NOT RESULT IN ADVERSE IMPACT ON THE DRAINAGE OF THE DOWNSTREAM DRAINAGE. THE RESULTING DISCHARGE DOES NOT CAUSE FLOODING OF THE DRAINAGE SYSTEM AND DOES NOT RESULT IN EROSIVE VELOCITIES TO THE EXISTING STORM SEWER. THE ANALYSIS OF THE PROPOSED PARK DOES NOT INCLUDE THE DETENTION/SLOWING OF THE RUNOFF THAT WILL OCCUR WITH THE PROPOSED PERVIOUS SURFACES, PEAK RUNOFF RATES FROM THE SITE WILL BE LOWER THAN THOSE SHOWN. STORM SEWER CALCULATIONS - EXISTING OUTFALL STORM SEWER CALCULATIONS - PROPOSED C I T Y O F A L E X A N D R I A V I R G I N I A DRAINAGE AREA IMPERVIOUS PERVIOUS TOTAL SITE AREA (SF) 6229 44736 50965 ON-SITE TREATED (SF) 5445 0 5445 OFFSITE TREATED (SF) TOTAL TREATED (SF) 5445 ANY ON-SITE DISCONNECTED BY A VEGETATED BUFFER (25 FT) TOTAL ONSITE TREATED OR DISCONNECTED 5445 PROJECT DESCRIPTION DEVELOPMENT OR REDEVELOPMENT BMP TYPE AREA TREATED BY BMP (ACRES) IMPERVIOUS AREA TREATED BY BMP (ACRES) BMP EFFICIENCY PERMEABLE PAVEMNT 0.1250 0.1250 25 MISCELLANEOUS TOTAL WQV TREATED: YES NO DETENTION ON SITE: YES NO PROJECT IS WITHIN WHICH WATERSHED? TIMBER BRANCH/HOOFS RUN PROJECT DISCHARGES TO WHICH BODY OF WATER? CAMERON RUN THIS PROJECT INVOLVES THE RENOVATION OF A PORTION OF SIMPSON PARK. THE PROPOSED PAVERS EXCEED THE WQV REQUIREMENT FOR THIS SITE. WATER QUALITY DEFAULT VOLUME TOTAL IMPERVIOUS AREA= 6229 SQUARE FEET (0.143ACRES) WQV= 6229 x 1 2 " (0.0417')= 259.75 CF TOTAL VOLUME PROVIDE IN PERMEABLE PAVER BASE IMPERVIOUS AREA TREATED: 5,453 SF (227.4 CF) AREA OF PERVIOUS PAVERS 5,179 X 0.5 X 0.4= 1,036 CF STORMWATER MANAGEMENT DATA C-006 BMP MAP - POST DEVELOPMENT SCALE: 1" = 40' - D.A. TO PERMEABLE PAVERS - 5453 SF (0.125 AC) - D.A. UNCONTORLLED - 45,520 SF (1.045 AC) 1. RESPOND CITY COMMENTS DATED 1/23/17 2/22/17 00000539 161251-00