Fort Collins, Colorado

To support the U.S. Army Corps of Engineers in development of the Final Environmental Impact Statement (EIS) for the Northern Integrated Supply Project (NISP), Hydros created and applied a dynamic temperature model of the Cache la Poudre River. The temperature modeling was conducted recognizing the potential for increased diversion flows to adversely impact river water temperatures.

ADYN/RQUAL software was used to create a dynamic temperature model to quantify potential effects of the NISP alternatives on water temperature in the most vulnerable reaches of the Poudre River. The model consisted of a hydrodynamic model linked to a water-quality model, applying RMS, version 4.5. A 17.4 mile reach of the Poudre River was simulated, extending from the Poudre Valley Canal diversion to the Boxelder Gage. The model simulated hourly flow rates and temperatures for six months of the year, from April through September. Predictions over the simulated reach reflected the effect of flow rates, diversions, diversion structures, channel geometry, shading, and meteorological conditions.  The model was applied for the EIS and used in the 401 Certification application for NISP.