Drainage Report

The Basin 1 contributing area is 368392 sf of Woods in good condition. AA, i Fp The initial 100 LF is sheet flow with a slope of 5% in woods with light underbrus' The next segment is shallow concentrated flow 1260 If with a slope of 5.7% throtignawoudsvith ight 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 The proposed Tc for the area flowing to Detention 1 uses the following input Sheet flow 100 If @0.5% over grass Tc= 24 min Shallow concentrated flow 144 If over grass @ 6.9% Tc=0.6 min Shallow concentrated flow 642 If over pavement @ 2.6% Tc= 3.7 min Pipe flow 873 If of 18 inch pipe N= 0.13, To=1.9 min Total Tc = 30.2 min Un-detained Area associated with Basin 1. These are small area at the perimeter of the drainage area that have minimal distance to travel before exiting the area of analysis. The longest path is Sheet flow 70 If @ 8% over grass Tc=5.9 min Detention basin 1 collects water from the east side of the site that drains to the Canoe Brook. The existing conditions have been modeled with a coverage as woods is good condition as required by the standards with NOAA type D rainfall curves. The table below outlines the results of the routing for this area. Filterra Treatment devices have been added prior to each paved surface inlet providing approved green technology water quality treatment for the basin Large scale Infiltration basins are listed as green technology for quantity in Table 5-2. The basin has been routed without exfiltration for the quantity Without Exfiltrations EXISTING Permitted DETENTION | OVERLAND] TOTAL (CFS) (CFS) (CFS) (CFS) (CFS) 2YR 4.51 2.26 0 1.36 1.36 10 YR 11.02 7.71 75 2.97 3.72 100 YR 25.26 20.21 2.09 6.40 8.49 Water Quality Water Quality is attained with Filterra treatment devices which are approved as green technology for 80% suspended solids removal. Groundwater Recharge Because green technology has been provide for 80% suspended solid removal the groundwater recharge has been calculated and included in the recharge spreadsheet. 4 Detention Basin 2 Area Anderson Consulting Services LLC 40 Miller Drive, Boonton, NJ 07005 973-975-0703 (O) 973-886-7336 (C) PAndersonpe@gmail.com