Report 4 13 2026

​ENSURPLAN, INC.​ ​ ww.Ensurplan.​​net​ w ​ ivil Engineers & Land Surveyors C Ph: (732) 469-0400​ ​Certificate of Authorization 24GA27997700​ ​STORMWATER DRAINAGE REPORT​ ​04/13/26​ ​Minor Subdivision 15 Ridgeway Ave West Orange, NJ​ ​Project Scope and Stormwater Management System Overview​​(continued)​ I​nfiltration may be used in the model of the stormwater basin routing as all runoff entering the​ ​system from developed surfaces receives pretreatment by either a gutter screening system or​ ​by passing through the permeable pavement layer. The basin shall, through the use of​ ​infiltration and orifice control, provide the required stormwater quantity reductions, recharge​ ​volumes and the required 80% reduction of total suspended solids for water quality.​ ​Design Discussion​ ​ tormwater analysis of the project is accomplished utilizing HydroCAD version 10.20-8a​ S ​Software furnished by HydroCAD Software Solutions LLC. The SCS-TR20 methodology is used​ ​to analyze NOAA 24 hr type C storms for both the current (2020) and projected (2050) 2, 10 and​ ​100 year rainfalls along with the NJDEP 2 hour water quality design storm.​ ​ he model of this project focuses solely on the “developed” area of the site within the drainage​ T ​area directed towards the residential properties to the north. As the Township stormwater​ ​ordinance defines the reconstruction of a home or milling or replacement of pavement as​ ​placement of new impervious surface, all impervious surfaces within this area whether driveway​ ​or existing roofs shall be considered “new” and altered from a good condition wood ground​ ​cover. The remaining portions of this drainage area which shall not be proposed with an​ ​impervious cover are considered existing lawn conditions to remain, and therefore are not​ ​included within the study.​ ​ small portion of the paved driveway stem from which runoff flows from the existing highpoint​ A ​towards Ridgeway Ave is considered as replacement as it has existed prior to 1980 and​

the study.​ ​ small portion of the paved driveway stem from which runoff flows from the existing highpoint​ A ​towards Ridgeway Ave is considered as replacement as it has existed prior to 1980 and​ ​continues to drain towards Ridgway Ave.​ ​These areas are depicted on the drainage area map.​ ​ he area of the site to be studied in the existing condition is modeled as type “C” HSG with​ T ​ground cover type of “good condition woods” with a curve number of 70. The time of​ ​concentration was calculated as 10.9 minutes consisting of sheet and shallow concentrated flow​ ​from the rear of the proposed homes travelling to the study point which shall be the existing inlet​ ​to the rear of the site. The existing study area totals 18,843 sf.​ ​4​ ​Mailing Address: Post Office Box 4304, Warren, NJ 07059​