|Title||Continuous Hydrologic Simulation of Johnson Creek Basin|
Shimota, Richard J.
Hadley, Hans R.
|Date Issued||2011-05-25 (iso8601)|
|Note||Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR.|
|Abstract||Peak discharge estimates are fundamental in the design of hydraulic structures, embankment protection, and stream restoration efforts, as well as flood risk analysis. Historic stream gage records are commonly used in the development of peak discharge estimates for a particular watershed. Use of an entire stream gage record assumes hydrologic stationarity within the basin of interest. However, changes in land use or climatic conditions may invalidate the assumption of hydrologic stationarity. An alternative to estimation from historic gage records is the development of peak discharges from a continuous hydrologic simulation and incorporating known or predicted changes to the hydrologic regime of the basin.
This presentation addresses an application of long-term continuous hydrologic simulation using Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS). A long term simulation of Johnson Creek basin was developed using current land use conditions in order estimate peak discharges for the City of Gresham flood study. The calibrated HEC-HMS model used a precipitation record of 61 years. The HEC-HMS model setup, calibration and verification are described. The non-stationarity of the Johnson Creek basin, the computed 100-year peak discharge estimate derived from long term simulation, and stream gage records are compared.