Through the Catskill Watershed Corporation (CWC) Stormwater Planning and Assessment Grant Program, Delaware Engineering carried out stormwater assessments for the Town of Windham in 2009 and again in 2017.

The CWC administers three New York City-funded programs to help municipalities, businesses and property owners address and correct stormwater runoff problems which may contribute to degraded water quality, and to plan ways to avoid runoff problems. The process contributes to the protection of New York City drinking water and helps local municipalities avoid flooding issues.

The project scope of work included conducting a stormwater infrastructure inventory, GIS development, data analysis, and crafting recommendations for stormwater infrastructure improvement planning. Delaware Engineering utilized a Data Reference Manual for documenting existing conditions of culverts, pipes, structures and swales that was initially developed by Greene County Soil and Water Conservation District personnel. Field forms were developed based on this guide.

Data collection involved field-locating the stormwater infrastructure using a Trimble Pro XRS GPS receiver and evaluating conditions. Swales were considered any open ditch feature and GPS data were collected as a line feature. Culverts, pipes and structures were located as point features using GPS.

Using ESRI ArcView software, the data was mapped and analyzed. A complete listing of stormwater structures was provided in an ArcView GIS database. Stormwater infrastructure was evaluated to identify areas that represented a potential source of sediment/pollutants to the Batavia Kill and to identify conditions that could result in localized flooding. Recommendations for retrofitting problematic structures were provided to support creation of prioritized mitigation programs for potential solutions to improve stormwater management and the quality of stormwater runoff.