Montclair Stables Drainage Report 1 10 25

INTRODUCTION This report is submitted in support of an application to the Township of West Orange for site plan approval. The Applicant, Montclair Stables LLC, has purchased the existing equine facility on Woodland Avenue and proposes to make improvements to the site. The primary improvements are the re-orientation and reconstruction of the existing outdoor sand riding arena and the re-location of the paved parking lot and driveways. The Applicant also proposes to make improvements to Nicholas Avenue, a paper street located at the rear of the property. This facility has used part of Nicholas Avenue as a driveway for decades. The proposed improvements include extending the driveway to connect to the paved portion of Nicholas Avenue near its intersection with Cannon Street. The driveway would function as a one-way driveway which would exit near the Cannon Street intersection and there would be new security gates at both ends. There are presently two buildings on the site, a barn and an indoor riding arena which are connected by a one-story concourse. There are no changes proposed to the configuration of these buildings. The Existing Drainage Area Plan, as well as the Existing Conditions Plan in the application set, depict a dwelling and related improvements which existed on Lot 176 until recently. EXISTING DRAINAGE The existing drainage patterns are indicated on the attached Existing Drainage Areas Plan. The area considered includes the site, a portion of Nicholas Avenue, a small portion of adjacent Lot 132 and an existing bridle path on Lots 1 and 2 in Block 152.26. An easement for the bridle path appears on the Tax Map. The total study area includes 175,847 square feet, or 4.037 acres. Under present conditions, five drainage areas were identified. Drainage Area A includes 19,498 square feet. This area is on the west side of the site and drains onto adjacent Lots 162 and 172. This area includes part of the existing riding arena, a lightly wooded area adjacent to Lot 162, the rear and west side of Lot 176 and approximately one quarter of the paved parking lot. Nearly all the runoff to Lot 172 is intercepted by the curbed, paved driveway and is directed to the curbline of Woodland Avenue. Drainage Area B includes the front yards of the buildings, a small portion of the roof area, the majority of the existing paved parking lot and approximately one quarter of

urbline of Woodland Avenue. Drainage Area B includes the front yards of the buildings, a small portion of the roof area, the majority of the existing paved parking lot and approximately one quarter of Lot 176 and drains onto Woodland Avenue. The area is 22,685 square feet. No formal drainage system exists for the parking lot. Drainage Area C includes 64, 808 square feet. This drainage area encompasses most of the center of the site and a portion of Nicholas Avenue as shown. Approximately three quarters of the roof surface is in this drainage area, as is the land between the barn and the indoor riding arena. Drainage Area C drains to an existing type E inlet in Nicholas Avenue and ultimately to the municipal drainage system located in an easement between Lots 5 and 6 in Block 152.26. Part of this drainage area is tributary to an existing riprap swale that is connected to a type E inlet at the west side of the indoor riding arena by a 12” corrugated metal pipe and flows to the type E inlet in Nicholas Avenue through a 15” corrugated metal pipe. Page 1