Historical hourly or daily precipitation data in gridded format can be imported into a HEC DSS file used by HEC-HMS as time series gridded dataset or gridsets. The commonly available…
Historical hourly or daily precipitation data in gridded format can be imported into a HEC DSS file used by HEC-HMS as time series gridded dataset or gridsets. The commonly available…
NOAA Atlas 14 provides the latest official U.S. precipitation frequency (PF) estimates for various durations and frequencies with lower and upper bounds of the 90% confidence interval. Refer to Post…
Two calibration methods are available in HEC-HMS: semi-automatic calibration using computation points and automatic calibration using optimization trial runs. This post is to focus on calibration by optimization trial runs.…
Two calibration methods are available in HEC-HMS: semi-automatic calibration using computation points and automatic calibration using optimization trial runs. This post is to focus on computation point calibration. Calibration by…
Peak flows of different frequencies calculated from hydrologic modeling often need to be validated to gain some confidence on them. There are several ways to validate a peak flow value.…
Urbanization has some substantial impacts on a watershed hydrology including increased surface runoff flow rate and volume, quicker to peak, decreased infiltration and evapotranspiration. To account for these effects in…
SCS Curve Number (CN) method, proposed by USDA Soil Conservation Service (SCS, now known as NRCS), has been widely used for infiltration loss and runoff calculation due to its simplicity…
As a theory-based infiltration method, Geen-Ampt is widely used in hydrologic modeling since its parameters are easy to acquire, especially for those project sites without monitored data for model calibration.…
In addition to loss through infiltration, during a precipitation-runoff process other losses may need to be accounted for as well, which include canopy interception, surface depression storage, and evapotranspiration (ET).…
Initial and Constant Loss Method and Deficit and Constant Loss Method are two common infiltration methods in HEC-HMS and they share the same underlying concept, simply put, after the "initial…