| AET | actual evapotranspiration |
| AIDS | Acquired Immunodeficiency Syndrome |
| ATU | aerobic treatment unit |
| AU | animal units |
| AVGWLF | Arc View GWLF |
| BACT | best available control technology |
| BG | billion gallon |
| BMP | best management practice |
| BOD | biochemical oxygen demand |
| BWS | Bureau of Water Supply |
| CBOD | carbonaceous biochemical oxygen demand |
| CBUDSF | continuously backwashing upflow dual sand filtration |
| CDC | Centers for Disease Control and Prevention |
| CDIC | Catskill/Delaware Interconnecting Chamber |
| CE | conservation easements |
| CFI | continuous forest inventory |
| CFP | Catskill Forest Preserve |
| CFU | colony forming unit |
| CMF | continuous microfiltration |
| CREP | Conservation Reserve Enhancement Program |
| CSBI | Catskill Streams Buffer Initiative |
| CTCP | Catskill Turbidity Control Program |
| CWA | Clean Water Act |
| CWC | Catskill Watershed Corporation |
| CWMP | Community Wastewater Management Program |
| DBP | disinfection byproduct |
| DEC | Department of Environmental Conservation |
| DEM | digital elevation model |
| DEP | Department of Environmental Protection |
| DO | dissolved oxygen |
| DOC | dissolved organic carbon |
| DOH | Department of Health |
| DOHMH | Department of Health and Mental Hygiene |
| DOM | dissolved organic matter |
| EOH | east-of-Hudson |
| EOHWC | EOH Watershed Corporation |
| EPA | U.S. Environmental Protection Agency |
| EPSC | erosion prevention and sediment control |
| FAD | filtration avoidance determination |
| FBO | Flood Buyout Program |
| FC | fecal coliform |
| FEIS | final Environmental Impact Statement |
| FEMA | Federal Emergency Management Agency |
| FTE | full-time equivalent |
| GIS | Geographical Information Systems |
| GLM | General Lake Model |
| GPS | Global Positioning System |
| GWLF | Generalized Watershed Loading Function |
| HAB | harmful algal bloom |
| HEC-RAS | Hydrologic Engineering Center’s River Analysis System |
| HEV | human enteric viruses |
| HIV | human immunodeficiency virus |
| HPC | heterotrophic plate counts |
| HRU | hydrologic response unit |
| IESWTR | Interim Enhanced Surface Water Treatment Rule |
| IRSP | Individual Residential Stormwater Permit |
| LAP | Land Acquisition Program |
| LFA | Local Flood Analysis |
| LID | low-impact development |
| LIDAR | Light Detection and Ranging |
| LOESS | locally weighted smoothing |
| LRAA | locational running annual average |
| MBR | membrane bioreactor |
| MCL | maximum contaminant level |
| MCLG | maximum contaminant level goal |
| MEP | maximum extent practicable |
| MGD | million gallons per day |
| MOA | Memorandum of Agreement |
| MS4 | municipal separate storm sewer system |
| MSL | mean sea level |
| MST | microbial source tracking |
| NANI | net anthropogenic nitrogen inputs |
| NAPI | net anthropogenic phosphorus inputs |
| NASEM | National Academies of Sciences, Engineering, and Medicine |
| NCD | natural channel design |
| NCRS | Natural Resource Conservation Service |
| NFC | natural features criteria |
| NLCD | National Land Cover Database |
| NOAA | National Oceanic and Atmospheric Administration |
| NOM | natural organic matter |
| NPDES | National Pollutant Discharge Elimination System |
| NRC | National Research Council |
| NRCS | Natural Resources Conservation Service |
| NTU | nephelometric turbidity units |
| NWI | National Wetland Inventory |
| NWS | National Weather Service |
| NYC | New York City |
| NYS | New York State |
| OST | Operations Support Tool |
| PCR | polymerase chain reaction |
| PET | potential evapotranspiration |
| PFAS | per- and polyfluoroalkyl substances |
| PFOA | perfluorooctanoic acid |
| PFOS | perfluorooctane sulfonate |
| SCM | stormwater control measure |
| SDWA | Safe Drinking Water Act |
| SMIP | Stream Management Implementation Program |
| SMP | Stream Management Program |
| SPARROW | Spatially Reference Regressions on Watershed Attributes |
| SPDES | State Pollutant Discharge Elimination System |
| SRP | soluble reactive phosphorus |
| SS | suspended solids |
| SSC | suspended sediment concentrations |
| STRP | sediment turbidity reduction project |
| SUNY | State University of New York |
| SWAT | Soil and Water Assessment Tool |
| SWAT-HS | SWAT-Hillslope |
| SWAT-VSA | SWAT-Variable Source Area |
| SWCD | Soil and Water Conservation District |
| SWMM | Storm Water Management Model |
| SWPPP | stormwater pollution prevention plan |
| SWTR | Surface Water Treatment Rule |
| TC | total coliform |
| TDP | total dissolved phosphorus |
| TI | topographic index |
| TMDL | Total Maximum Daily Load |
| TOC | total organic carbon |
| TP | total phosphorous |
| TSI | Trophic State Index |
| TSS | total suspended solids |
| TTHM | total trihalomethanes |
| USDA | U.S. Department of Agriculture |
| USFS | U.S. Forest Service |
| USGCRP | U.S. Global Change Research Program |
| USGS | U.S. Geological Survey |
| UV | ultraviolet |
| VSLF | Variable Source Loading Function |
| WAC | Watershed Agricultural Council |
| WAP | Watershed Agricultural Program |
| WDRAP | Waterborne Disease Risk Assessment Program |
| WECC | Watershed Enforcement Coordination Committee |
| WFP | Watershed Forestry Program |
| WMP | Waterfowl Management Program |
| WOH | west-of-Hudson |
| WR&R | Watershed Rules and Regulations |
| WRTDS | weighted regressions on time, discharge, and season |
| WTM | Watershed Treatment Model |
| WWTP | wastewater treatment plant |