The information contained in this site uses the best data available from a variety of resources. While the SRAT technical team strives to present the most recent data, The Open Space Institute, The Academy of Natural Sciences of Drexel University, Penn State University, The Institute for Conservation Leadership and The William Penn Foundation do not assume responsibility for the spatial accuracy or timeliness of data used. We disclaim any and all responsibility for errors, preclusion or other inconsistencies depicted arising from or otherwise related to this dataset. This map is intended for Phase II planning of the Delaware River Watershed Initiative and should not be used for regulatory purposes.  

GIS Professionals

We recommend that you download the SRAT dataset. There are four datasets that can be downloaded at this time:


regular Users

We recommend that you use the SRAT Story Map to guide you through the preliminary stages of your planning process. *

* If your cluster requires more complex mapping with the SRAT data than is provided by the Story Map, please reach out to the SRAT technical team at ans_bgidata@drexel.edu so that we may assist you. 


  • Yield: Amount of TP, TN, or TSS per area (lbs/acre).
  • Concentration: Amount of TP, TN, or TSS in a volume of water (mg/L).
  • Load: Amount of TP, TN, or TSS (lbs)
  • Total catchment: A NHDPlus V2 catchment plus all other NHDPlus V2 catchments that drain into it.
  • Local catchment: A NHDPlus V2 catchment.
  • Thresholds: Point at which biological communities and/or water quality in a waterbody may change from "unimpaired" to "impaired" due to pollutant increases.
  • TN: Total nitrogen (including all species of dissolved and particulate forms)
  • TP: Total phosphorus (including all species of dissolved and particulate forms)
  • TSS: Total suspended solids (primarily sediment)
  • BMP: Best management practices.
  • Limiting nutrient: A nutrient that, if increased in a waterbody, will result in increased productivity.