PRMS — The Complete Guide: Watershed Modelling from Precipitation to Streamflow
PRMS (Precipitation-Runoff Modeling System) is a USGS watershed hydrology model. It divides the basin into hydrologic response units and follows water from precipitation and snowmelt, through evapotranspiration, surface runoff and infiltration, to streamflow. It is in the public domain, with ready-to-run packages for Windows and Linux plus source code.
PRMS
U.S. Geological Survey (USGS)
Watershed hydrology model: from precipitation to runoff, infiltration and streamflow.
Get it from the vendorWhat you get
- Full water budget — every part of the basin water cycle, day by day.
- Snow and evapotranspiration — snow accumulation, melt and evapotranspiration.
- Climate and land-use scenarios — comparing flows under different conditions.
- Basis for coupled models — the surface component of GSFLOW.
- Interface and examples — a basic Java graphical interface and sample projects.
Who it suits and what to know
Hydrologists and water-resources engineers studying a basin’s long-term water budget. It is not a quick tool for a single-event design flow. Preparing spatial parameters for a real basin takes separate GIS work, the interface is basic and needs Java, and without calibration against measured streamflow the results cannot be trusted.
Related tools
For coupling with groundwater — GSFLOW. For event rainfall-runoff and drainage design — HEC-HMS. For agricultural basins with water quality — SWAT.
GSFLOW
U.S. Geological Survey (USGS)
Coupled groundwater and surface-water model for whole watersheds, linking PRMS with MODFLOW.
Get it from the vendor
HEC-HMS
US Army Corps of Engineers
Rainfall-runoff hydrological model — infiltration, unit hydrograph and routing. Pairs with HEC-RAS.
Get it from the vendorSWAT
Texas A&M AgriLife / USDA-ARS
A watershed model — runoff, erosion, nutrients and pesticides over decades.
Get it from the vendor
QGIS
QGIS.org
Open-source GIS for spatial analysis, layer work and map production.
Get it from the vendorThe bottom line
PRMS is a long-established model for basin water budgets. It needs data preparation and calibration, but it is completely free and well documented.