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​ ​Infiltration Mounding Analysis​ ​ he mounding of the infiltrated water below the basin bottom is modeled utilizing the Hantush​ T ​spreadsheet calculator downloaded from the NJDEP.​ ​ epth for the mounding analysis is based on the maximum depth of the projected 100 year​ D ​storm or 3.44 feet.​ ​The initial calculation inputs are as follows​ ​ he recharge rate, R,or the permeability rate utilized is ½ of the measured rate of 1.0”/hr​ T ​R=0.5 “/hr​ ​ he basin dimensions for spread sheet entry were 65’’ x 6.5’. Because the basin shape is linear​ T ​the spread sheet is run twice with the x and y values transposed.​ ​The specific yield utilized was the default value of 0.15.​ ​The horizontal hydraulic conductivity was set equal to the design permeability rate of 0.5”/hr.​ ​The duration of the infiltration period was calculated as follows.​ ​Infiltrated Vol (0.045 af) (43,560 sf) (12”) / Footprint (1,600 sf) (0.5”/hr) = 29 hrs​ ​The initial thickness of the saturated zone utilized was the default value of 10 feet.​ ​ esults indicate a zero change in mounding at a distance 23.5’ from the long axis of the pond​ R ​and a zero change in mounding at a distance 25’ from the long axis of the pond. There are no​ ​building structures with a basement within the area which would experience an increase of​ ​ground water elevation.​ ​13​ ​Mailing Address: Post Office Box 4304, Warren, NJ 07059​