Drainage Report

The existing conditions of the drainage area that is routed to Basin 2 a forested ah \ifie? GS underbrush due to deer over browsing. The path of the existing conditions Tc isshol Existing Conditions Drainage Area Map. The Tc is calculated in the Hydrocad prégrertawitrrtHes -c factors shown on the map and is as follows. The Basin 2 contributing area is 465453 sf of Woods in good condition. The initial 100 LF is sheet flow with a slope of 0.5% in woods with light underbrush. Tc=14.4 min The next segment is shallow concentrated flow 1260 If with a slope of 5.7% through woods with light underbrush. There is no discernable channel in the field along this path that would change the categorization of the flow type. Tc = 17.6 min. Total pre-development Tc= 32 min Basin 2-1 Tc. Basin 2-1 collects runoff by overland flow from the area down hill of the dog park. The 17,946 sf area will be grass cover and the Tc was computed with the flowing factors Sheet flow 100 LF @6% Tc=6.1 Min Shallow concentrated flow 90 If @ 3.4% Tc=.5 min Total Tc = 6.6 min Basin 2-2 Tc. Basin 2-2 collects runoff from the parking area behind Building A. The area of 61,497 sf is mostly paved coverage with grass area outside and the Tc was computed with the following factors. Sheet Flow 60 LF @13 % grass cover Tc= 3min Shallow concentrated flow 120 If @ 4.5% Tc =.5 min, grass cover Pipe Flow 426 If of 12 inch pipe @ 3.5% N=0.01 Tc 1.1 min Total Tc = 4.6 min Basin 2-3 Tc. Basin 2-3 collect runoff from the area around the clubhouse and a portion of Kusik Drive. The Tc was computed with the following factors. Sheet Flow 100 LF @3% grass cover Tc= 8 min Shallow concentrated flow 60 If @ 3.3% Tc = .4 min, grass cover Shallow Concentrated Flow 72 LF@ 8% Tc =.2 min, Pavement Cover Pipe Flow 1326 If of 15 inch pipe @ 3% N=0.01 Tc 1.9 min Total Tc= 10.5 min Basin 2-4 Tc basin 2-4 collects runoff from behind Building C and the clubhouse parking lot. The Tc was computed with the following factors. Sheet Flow 100 LF @8% grass cover Tc= 5.4 min Shallow concentrated flow 120 If @ 2% Tc =.9 min, grass cover Pipe Flow 1692 If of 15 inch pipe @ 3.7% N=0.01 Tc 3.7 min Total Tc= 10 min 5 Anderson Consulting Services LLC 40 Miller Drive, Boonton, NJ 07005 973-975-0703 (O) 973-886-7336 (C) PAndersonpe@gmail.com