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
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.
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
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