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Warwick Schools Bioretention Area


view of bioretention area - vegeated area with woods in the far background

An expansive asphalt parking lot behind the school's building complex drains to the Wawayanda Creek, which is only about 200 feet from the lower edge of the parking lot. Although an "early generation" stormwater detention basin receives the runoff before it reaches the Creek, this practice primarily attenuates flood flows but has limited water quality benefits. Adding a filtering practice in the form of this bioretention basin complements the storm water management of the parking lot runoff by adding significant pollutant removal capability while infiltrating a portion of the runoff to better mimic pre-development conditions.

The existing parking lot storm drainage collection system was retrofitted by adding a "low flow" pipe at the bottom of a catch basin that receives most of the parking lot runoff. This low flow pipe captures the "first flush" and low flows from the parking lot - diverting them from the pre-existing detention basin and directing them to the new bioretention area. Additional runoff from the parking lot reaches the bioretention area by overland flow.

Site Location

  • Site location: Warwick Valley Central School District
  • Address: 89 Sandfordville Road, Warwick, NY 10990
  • Owner: Warwick Valley Central School District
  • County: Orange
  • Watershed: Wawayanda Creek/Wallkill River
  • Land use of this site: School
  • Can this site be visited? Yes, but access to the public is limited
  • Location on site: South of the building complex, east of Sandfordville Road, west of the campus track/sportsfield

Practice Details

  • Intent of design: To install a retrofit bioretention practice to remove pollutants and infiltrate a portion of the runoff, complementing an existing stormwater detention pond that mitigates flooding
  • Size of structure/capacity: 3,800 square feet surface area/1,900 cubic feet ponding/storage volume
  • Size of drainage area: 5 acres
  • Plants or materials used: partial list of plants used: Carex, Cardinal Flower, Joe Pyeweed, Sedum, Daylily, Roseanne Cranesbill
  • Maintenance: Weed, water, replace plants
  • Maintained by: Volunteers from school, Orange County Soil and Water Conservation District

Design/Installation Information

  • Design: Lehman and Getz, P.C.
  • Installation: Vellenga Lawn Care, with construction supervision by Orange County Soil and Water Conservation District
  • Other project partners: Warwick Valley Central School District - approve project, assist with maintenance
  • Date of installation: August 2014
  • Zoning change or special permit required: No
  • Project cost: Approximately $20,000
  • Form of payment: Grant funds (from the NYS DEC Hudson River Estuary Program, in partnership with New England Interstate Water Pollution Control Commission), additional support from Orange County Soil and Water Conservation District, Warwick Valley Central School District, Lehman and Getz, P.C.

For Additional Site Information:

Contact: Kevin Sumner, Conservation District Manager, Orange County Soil and Water Conservation District


Phone: (845) 343-1873