NRCS Wetlands Modeling with SPAW and DRAINMOD

Executive Summary:
The USGS, in cooperation with the NRCS, will develop, calibrate, and verify SPAW and
DRAINMOD application models as requested by NRCS for use by NRCS at agricultural
locations in North Dakota. The models will be used to estimate the daily water balances of the
upland areas and the daily water balances including runoff amounts to wetlands at the study
locations. Additionally, application of the SPAW model to cold weather regions, such as North
Dakota, which experience annual freezing/thawing of the soil profile, will provide additional
insight to parameter estimation during snow accumulation and melt. The use of both SPAW and
DRAINMOD models for analyzing the hydrology of wetlands in North Dakota provides two
approaches utilizing different methodologies to analyze wetland hydrology.

Objective(s):
Objectives of the study include 1) developing a better understanding of parameter development
for SPAW and DRAINMOD models in North Dakota, 2) determining field data requirements for
model calibration and verification, and 3) understanding model limitations in field applications.