29906 15 Ridgeway Minor Subdivision R3 5 26 2026

BYPASS TO INLET STUDY POINT FOR ANALYSIS PRE DEVELOPED Q 2yr = 0.90 cfs Q 10yr = 2.24 cfs : Q 100yr= 5.34 cfs n QP 2yr = 1.34 cfs Hi Q P 10yr = 3.11 cfs # QP 100 yr = 7.53 cfs Q 10yr = 1.35 cfs Q 100yr= 4.18 cfs | Q P 2yr = 0.64 cfs fq LOT 21 QP 10yr = 2.12 cfs | QP 100 yr = 5.85 cfs \ LOT 21.01 10” SDR 35 PVC DRAIN CONNECTED 10 PUBLIC STORM SEWER™“"¥ MAX OUTFLOW Q = 1.08 cfs 563.00 8” FES 6x12’ 4” Rip Rap Level Spreader * Post development runoff is reduced for all design DEVELOPED storms from what would have occurred if the site was undeveloped and wooded. No credit taken in Q 2yr = 0.42 cfs the analysis for existing impervious to remain. Landscape Block Wall Max Height 36” Top Wall | 566.0 / y | ROW Fo TC PATH Ay YARDS TO BASIN SHEET FLOW 24.7 MIN. 4 3 214' @ 2.1% ; : BYPASS AREA ROOF EAST =; LOT 28.02 DIRECT TO INLET Y asewENt . TO REAR BASIN < | EXISTING DWELLING 7,274 SF 7 Moves _— tc paty 3:867 SF | S | } ROOF WEST. | ROOF TO BASIN E “| “TO REAR BASIN 0.4 MINUTES (PIPE FLOW) | cr ”~”SY | 150 LE @ 2% | | | | : ) | van — \ | wdyeeee | \ Ni \ ° \ \ 2 “Xt \ f ww / e NL raven | & , PROPOSED ee | yee : 2 opRorose> Ml CURBED DRIVEWA i \ | PICKET ELEV = 568.0 x \ 8 568% am — <— a weceeeeeeee joe 4 TC PATH k K=1.00°7He SHWa560.3, EXISTING DRAINAGE AREA BOUNDARY (—_— ) PIORET FENCE EXISTING DRAINAGE AREA 48,268 SF TOTAL 08" GOOD WOODS CN 70 ~. ) ) 5 ee 4 2 PROPOSED CONDITIONS STUDY LAND USE PLANNING AND SOURCE CONTROL PLAN & STORMWATER MANAGEMENT FACILITIES MAP 276.95" i S_65°20'50” EF [ee PAVEMENT oD Ss 231'@26% *& SHEET FLOW..2 24.1 MIN. \ yn - Rw 56! (_UTILITY ko os? fo AND GUY WIRES’ = MAJOR STORMWATER DESIGN JUSTIFICATION/DESCRIPTION This report has been prepared to demonstrate that the runoff from the proposed improvements to the site, which result in an increase of impervious coverage, is properly mitigated in accord with the requirements for a NJ DEP major stormwater project, and will pose no negative impact to any surrounding downstream properties. To ensure that the design complies with the requirements and goals of the Township Stormwater Ordinance a detailed analysis of the site condition was performed. A soils evaluator tested various areas of the site to identify both seasonal high water levels and the ability of the soil to infiltrate runoff. Additionally areas allowing for use of low impact development were

luator tested various areas of the site to identify both seasonal high water levels and the ability of the soil to infiltrate runoff. Additionally areas allowing for use of low impact development were identified; including potential preservation of large deciduous trees, lessening the slope of surfaces and elongation of drainage paths. This study focused the design on the area of the site which would allow for use of infiltration. Two stormwater management basins were designed for the project. The first, known as the “Front Yard Basin”, a small scale sub-surface extended infiltration basin (a system allowing for infiltration and controlled release) was chosen as the green infrastructure BMP to provide infiltration and recharge as well as reduction of runoff quantity. The basin is located at the area of the site where the soils evaluation determined an acceptable infiltration rate for design (A factor of safety was applied to the analysis by utilizing 8 of the measured infiltration rate in all calculations). The ‘Front Yard Basin” works in conjunction with the proposed permeable pavement, another green infrastructure BMP, which is specified for all driveway surfaces. When rainfall from the Water Quality Storm is filtered by passing through the permeable pavement, conveyed to the basin and infiltrated, the system is rated for 80% total suspended solids reduction providing water quality treatment for the site. Runoff entering the permeable pavement shall be collected within a stone bed below the pavement. It is proposed to allow runoff to travel through the stone bed (supplemented by a series of perforated pipes) and enter the infiltration basin. The second basin, known as the “Rear Yard Basin”, collects runoff from roof surfaces, lawn areas, sidewalks and patios. As these surfaces are not subject to vehicle traffic provision of water quality treatment for this runoff is not required. The “Rear Yard Basin” is located at an area where the measured infiltration rate is less than 1”/hr, therefore although some infiltration will occur, it is not considered within the routing of the basin. The basins shall be shared systems, accepting runoff from both lots, therefore easements allowing for common use and maintenance shall be established. Operations and maintenance requirements and responsibilities shall be filed with the record owner deeds. The analysis shows

ore easements allowing for common use and maintenance shall be established. Operations and maintenance requirements and responsibilities shall be filed with the record owner deeds. The analysis shows that the runoff from the developed portion of the site directed towards the stormwater basins when combined with the runoff rate from the portions of the site which bypass the system, has been reduced to no more than 50% of the two year storm rate. 75% of the 10 year storm rate and 80% for the 100 year storm rate from what would have occurred if the design area were an undeveloped wooded lot. Additionally, provisions for recharge and water quality have been provided and meet the requirements of the NJ DEP. The project also meets the requirements of the Township of West Orange Stormwater Ordinance with the exception of retaining the design “retention storm”. The limitations of the sub—soil on the property will not allow for infiltration of this volume, which exceeds the NJ DEP requirements, and a waiver will be required. The proposed improvements provide a reduction in runoff rate from what occurs currently, provides water quality for motor vehicle surfaces where none is currently provided, and maintains 100% of the existing infiltration on the site, justifying the requested waiver. N 65°20’50” W 528.66’ TC PATH FOR PERMEABLE PAVEMENT TO INFILTRATION (TRAVEL THROUGH PERFORATED PIPE AND/OR STONE BEDDING 0.4 MINUTES (PIPE FLOW) LAND _USE PLANNING DISCUSSION The total area of land disturbance is 1.10 Acres In accordance with the goals and standards of Chapter 25—29.3 through 25—29.5 of the West Orange Code this plan has been developed in the following manner. The project construction shall conform to a Soil Erosion and Sediment Contol Plan, to be reviewed and approved by the Conservation District. Green Infrastucture has been implemented into the design through use of permeable pavement systems which collect, store and direct runoff towards an infiltration basin, providing water quality, recharge and volume reduction. Additionally low impact development measures are implemented throughout the unstudied portion of the project which will lessen the overall stormwater runoff from the site to a greater extent. The measures include; preservation of large decidous trees along the site perimeter, lessening of slopes in the rear yard of proposed homes and

ll stormwater runoff from the site to a greater extent. The measures include; preservation of large decidous trees along the site perimeter, lessening of slopes in the rear yard of proposed homes and increasing drainage path routes in order to increase time of concentration. oO 5’ 10°15’ 20’ 25’ a \ eine HIGH POINT 50’ TABLE OF BMP INFORMATION 9 % ey ca APPROXIMATE LOCATION OF WATER LINE O.W.) (VARIABLE. Wit Revision Table: 3) 5-26-26 STORMWATER 2) TOWNSHIP ZONING/ENGINEERING REVIEW 04-13-26 1) UPDATE FOR NEW HOUSE PLAN 01-06-2026 0) INITIAL ISSUE 11-25-2025 WA Wihiphh WILLIAM S. SCOTT, P.E. Professional Engfieer, NJ. License N6. GE44863 h.QSa- NANCY J. SCOTT, P.L.S. BOTTOM S.H.W. INFILTRATION Professional Land Surveyor BMP DESCRIPTION ELEVATION ELEVATION RATE "/HR Nu. License No. GS35875 INFILTRATION BASIN 563.0 560.3 1.00 A PERMABLE PAVEMENT 566.5 560.3/561.0} N/A EN GRAPHIC SCALE 1°=20’ (Certificate of Authorization No. 24GA27997700) P.O. BOX 4304, WARREN, N.J. 07059 Tel: 732-469-0400 ensurplan@gmail.com LAND USE PLANNING AND SOURCE CONTROL STORMWATER MANAGEMENT FACILITIES MAP 15 RIDGEWAY AVENUE LOT 28.01 IN BLOCK 158 (TAX MAP SHEET NO. 91) SITUATED IN THE TWP. OF WEST ORANGE, ESSEX COUNTY, Nd SCALE: 1”=20' ORDER: E-11156 6 DATE: 11-25-2025 FILE: 29906 7