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HomeMy WebLinkAbout12030010.8Q N 0 M O } Y 0 a Q N O m M O } Y N Z Q K H fn ° a ° a -0 aN �Q 3m ° W 3N o� ° 03 o° N a Z -j Q J as ja U) I pw %m �m LJ w� w i� 3� /w tLja Y m 10 M w0 a r z� w U U w3 x° F- w J -t O N N rm'7 /x N / m N X i t"k_p ::: 'A r' , -1 i.. Nib 1 6 6 I',1 ' r OXGRE.EN RAC[_ H;OVIEOVVNEK`S ASSOC. DRAINAGE SUMMARY - SOUTH BASIN BASIN AREA AREA (AC.) PERMEABLE IMPERVIOUS AREA-POST CN (PRE-POST) PRE -DEV 10 -YR (CFS) F PAVEM €NT PERM. PVMT. REQUIRED (SF) 1.88 1.54 1.53 EXIST. STORM SEWER 10.40 14.93 10,500 Y W Ix WV — 2 o J i Wa y�l J W w � o EXISTING OUTLET PIPE U 0 P +- C PROPOSED r5 d C taG c �R�S. DRAINAGE SUMMARY - SOUTH BASIN BASIN AREA AREA (AC.) IMPERVIOUS AREA-PRE IMPERVIOUS AREA-POST CN (PRE-POST) PRE -DEV 10 -YR (CFS) POST -DEV 100 -YR (CFS) DETENTION VOL. REQ'D (CF) PERM. PVMT. REQUIRED (SF) 1.88 1.54 1.53 92 10.40 14.93 10,500 12,000 * ASSUMES 24" STONE DEPTH WITH 40% VOID VOLUME FOR STORAGE RESERVOIR EXISTI NG OUTLET PIPE STORMWATER MANAGEMENT APPROACH mm"m THE NORTHERN AND SOUTHERN LAND DISTURBANCE AREAS WILL BE REDEVELOPED IN ACCORDANCE WITH THE CITY OF CARMEL'S STORMWATER ORDINANCE REQUIREMENTS FOR THE PROVISION OF DETENTION AND POST - CONSTRUCTION TREATMENT OF RUNOFF. PER THE CITY'S REDEVELOPMENT POLICY, DETENTION WILL BE PROVIDED TO RELEASE THE POST - DEVELOPED 100 -YEAR STORM EVENT AT THE PEAK 10 -YEAR PRE- DEVELOPMENT RATE. IN LIEU OF THE PROVISION OF TWO POST - CONSTRUCTION BMP'S IN SERIES FOR THE NORTHERN AND SOUTHERN REDEVELOPMENT AREAS, A SINGLE BMP FOR EACH OF THESE AREAS WILL BE PROVIDED TOGETHER WITH A THIRD BMP TO TREAT PRESENTLY UNTREATED RUNOFF FROM THE CENTRAL PORTION OF THE SITE WHICH WILL REMAIN UNDISTURBED BY THIS PROJECT. THE APPROACH DEPICTED WITHIN THESE DEVELOPMENT PLANS RELIES UPON A LOW IMPACT DEVELOPMENT (LID) STRATEGY UTILIZING PERVIOUS PAVEMENT AND BIORETENTION ISLANDS WITHIN PORTIONS OF THE EXISTING AND PROPOSED PARKING LOTS TO TREAT AND DETAIN RUNOFF. THE DEVELOPER RESERVES THE RIGHT TO EMPLOYEE A CONVENTIONAL DESIGN APPROACH TO DETENTION AND TREATMENT VIA UNDERGROUND CHAMBERS AND MECHANICAL STORMWATER QUALITY TREATMENT UNITS (SQTU'S) IF PREFERRED. IF A CONVENTIONAL APPROACH IS EMPLOYED, EQUIVALENT STORAGE WILL BE PROVIDED IN CHAMBER SYSTEMS WITHIN THE NORTHERN AND SOUTHERN REDEVELOPMENT AREAS WITH TREATMENT PROVIDED BY SQTU'S BASED UPON THE WATER QUALITY FLOW RATE FOR EACH AREA. A THIRD SQTU WILL THEN BE PROVIDED TO TREAT PRESENTLY UNTREATED RUNOFF FROM THE CENTRAL PORTION OF THE SITE TO REMAIN UNDISTURBED. (n Z 0 U) w tY Z 0 I- a U W W Q O Y lY Q Q. 0 tY v O w I` � J a a a W I BASIN AREA AREA (AC.) z W W CN (PRE-POST) PRE -DEV 10 -YR (CFS) POST -DEV 100 -YR (CFS) DETENTION VOL. REQ'D (CF) j 1.98 a FZ 92 10.96 I- Z W 11,000 W Ix WV — 2 o J 0 0 Wa J W w � o EXISTING OUTLET PIPE P +- C r5 d C taG c W`u LV DRAINAGE SUMMARY - NORTH BASIN BASIN AREA AREA (AC.) IMPERVIOUS AREA -PRE IMPERVIOUS AREA - POST CN (PRE-POST) PRE -DEV 10 -YR (CFS) POST -DEV 100 -YR (CFS) DETENTION VOL. REQ'D (CF) PERM. PVMT. REQUIRED (SF) " 1.98 1.68 1.55 92 10.96 15.72 10,000 11,000 * ASSUMES 24" STONE DEPTH WITH 40% VOID VOLUME FOR STORAGE RESERVOIR Z� �06 m 0 w Wu w �- w Fj CL uva i L .lob No. 12016L a No. PE195M STATE 01 O,n � '� �n NgANP � l3 •,,;,s�ONAL Date: March 16, 2 Scale: 1 " =40' Title: STORMWAT MANAOEME PLAN Sheet: c5c