prms(1) U.S. Geological Survey (wrdapp) prms(1) NAME prms - Precipitation-Runoff Modeling System ABSTRACT PRMS is a modular-design, deterministic, distributed-parameter modeling system developed to evaluate the impacts of various combinations of precipitation, climate, and land use on streamflow, sediment yields, and general basin hydrology. Basin response to normal and extreme rainfall and snowmelt can be simulated to evaluate changes in water-balance relationships, flow regimes, flood peaks and volumes, soil-water relationships, sediment yields, and ground-water recharge. Parameter-optimization and sensitivity analysis capabilities are provided to fit selected model parameters and evaluate their individual and joint effects on model output. The modular design provides a flexible framework for continued model-system enhancement and hydrologic-modeling research and development. METHOD A watershed is divided into subunits based on such basin characteristics as slope, aspect, elevation, vegetation type, soil type, land use, and precipitation distribution. Two levels of partitioning are available. The first divides the basin into homogeneous response units (HRU) based on the basin characteristics. Water and energy balances are computed daily for each HRU. The sum of the responses of all HRU's, weighted on a unit-area basis, produces the daily system response and streamflow for a basin. A second level of partitioning is available for storm hydrograph simulation. The watershed is conceptualized as a series of interconnected flow planes and channel segments. Surface runoff is routed over the flow planes into the channel segments; channel flow is routed through the watershed channel system. An HRU can be considered the equivalent of a flow plane or it can be delineated into a number of flow planes. HISTORY 1991 version - Added option to output computed time series to the Watershed Data Management (WDM) file 1984 version - A WDM file replaces the ISAM file for the time-series data management 1983 version - Original version DATA REQUIREMENTS For daily streamflow computations, a minimum of daily precipitation and daily maximum and minimum air temperature are required. For snowmelt computations, daily short-wave solar radiation data are recommended. For areas without snowmelt, daily pan evaporation data can be substituted for temperature data. For storm hydrograph and sediment computations, short time-interval precipitation, streamflow, and sediment data are needed. Physical descriptive data on the topography, soils, and vegetation are input for each watershed subunit. The spatial and temporal variation of 7 Jul 1998 1 prms(1) U.S. Geological Survey (wrdapp) prms(1) precipitation, temperature and solar radiation are also needed. The input time-series data are read from a WDM file. OUTPUT OPTIONS The observed (if available) and predicted mean daily discharge for the basin is output in tabular form. Annual and monthly summaries of precipitation, interception, potential and actual evapotranspiration, and inflows and outflows of the ground water and subsurface reservoirs are available. The time series available at a monthly time step may also be output at a daily time step along with the available soil moisture, percent snow cover, pack water equivalent, and snowmelt. Most of the computed daily time series can also be written to the WDM file. This information is also available for the individual HRU's. A summary table of observed and predicted peak flows and runoff volumes for each storm period is output in tabular form. The inflow and outflow for user selected overland flow plans and channel segments can be output in tabular form, as "printer" plots, or to the WDM file. SYSTEM REQUIREMENTS PRMS is written in Fortran 77 with the following extension: use of include files. Some variable and routine names are longer than 6 characters. The UTIL, ADWDM, and WDM libraries from LIB are used. A subset of these libraries is provided with the code and may be used instead of the libraries; this subset uses INTEGER*4 and mixed type equivalence. For more information, see System Requirements in LIB. DOCUMENTATION Leavesley, G.H., Lichty, R.W., Troutman, B.M., and Saindon, L.G., 1983, Precipitation-Runoff Modeling System: User's Manual: U.S. Geological Survey Water-Resources Investigations Report 83-4238, 207 p. RELATED DOCUMENTATION Flynn, K.M., Hummel, P.R., Lumb, A.M., and Kittle, J.L., Jr., 1995, User's manual for ANNIE, version 2, a computer program for interactive hydrologic data management: U.S. Geological Survey Water-Resources Investigations Report 95-4085, 211 p. REFERENCES Carey, W.P., and Simon, A., 1984, Physical basis and potential estimation techniques for soil erosion parameters in the Precipitation-Runoff Modeling System (PRMS): U.S. Geological Survey Water-Resources Investigations Report 82-4218, 32 p. Cary, L.E., 1984, Application of the U.S. Geological Survey's Precipitation-Runoff Modeling System to the Prairie Dog Creek basin, Southeastern Montana: U.S. Geological Survey Water- Resources Investigations Report 84-4178, 98 p. Kidd, R.E., and Bossong, C.R., 1987, Application of the precipitation-runoff model in the Warrior Coal Field, Alabama: U.S. Geological Survey Water-Supply Paper 2036, 42 p. 7 Jul 1998 2 prms(1) U.S. Geological Survey (wrdapp) prms(1) Kuhn, G., 1989, Application of the U.S. Geological Survey's Precipitation-Runoff Modeling System to Williams Draw and Bush Draw basins, Jackson County, Colorado: U.S. Geological Survey Water-Resources Investigations Report 88-4013, 38 p. Norris, J.M., and Parker, R.S., 1985, Calibration procedure for a daily flow model of small watersheds with snowmelt runoff in the Green River coal region of Colorado: U.S. Geological Survey Water-Resources Investigations Report 83-4263, 32 p. Parker, R.S., and Norris, J.M., 1989, Simulation of streamflow in small drainage basins in the southern Yampa River Basin, Colorado: U.S. Geological Survey Water-Resources Investigations Report 88-4071, 47 p. Puente, C., and Atkins, J.T., 1989, Simulation of rainfall-runoff response in mined and unmined watersheds in coal areas of West Virginia: U.S. Geological Survey Water-Supply Paper 2298, 48 p. Scott, A.G., 1984, Analysis of characteristics of simulated flows from small surface-mined and undisturbed Appalachian watersheds in the Tug Fork basin of Kentucky, Virginia, and West Virginia: U.S. Geological Survey Water-Resources Investigations Report 84-4151, 169 p. TRAINING Watershed Systems Modeling I (SW2008TC), offered annually at the USGS National Training Center. CONTACTS Operation and Distribution: U.S. Geological Survey Hydrologic Analysis Software Support Program 437 National Center Reston, VA 20192 h2osoft@usgs.gov Official versions of U.S. Geological Survey water-resources analysis software are available for electronic retrieval via the World Wide Web (WWW) at: http://water.usgs.gov/software/ and via anonymous File Transfer Protocol (FTP) from: water.usgs.gov (path: /pub/software). The WWW page and anonymous FTP directory from which the PRMS software can be retrieved are, respectively: http://water.usgs.gov/software/prms.html --and-- /pub/software/surface_water/prms 7 Jul 1998 3 prms(1) U.S. Geological Survey (wrdapp) prms(1) SEE ALSO annie(1) - Program to list, table, plot data in a WDM file iowdm(1) - Program to store time-series data in a WDM file wdm(1) - Watershed Data Management system 7 Jul 1998 4