Rocky Mountain (53rd) and South-Central (35th) Sections, GSA, Joint Annual Meeting (April 29–May 2, 2001)

Paper No. 0
Presentation Time: 1:30 PM

VERIFICATION, UNCERTAINTY, AND SENSITIVITY ANALYSES FOR AN INTEGRATED WATER RESOURCES EVALUATION MODEL


ALY, Alaa H. and RUSKAUFF, Greg J., Boulder, CO 80301, aly@waterstoneinc.com

An integrated surface water/groundwater (ISGW) model has been developed for the Northern Tampa Bay area in west central Florida. The model covers about 3,600 square miles area that includes all of Pasco County, most of Hernando, Pinellas and Hillsborough counties, and parts of Lake, Sumter and Polk counties. Model parameters were calibrated for a time window starting in January 1971 and ending in December 1996. Observed hydrologic system responses for a three-year time window (1996-99) were used to verify the model predictive capabilities. Several tools were used in this evaluation, including time-series methods, spatial statistics methods, and conventional univariate statistics methods. These analyses showed that the model predictive capabilities are reflective of the model performance during calibration. Furthermore, while the integrated model was able to provide fairly accurate predictions of average hydrologic conditions, the model performance during dry periods was highly questionable. This suggested that the traditional calibration assessment metrics were not appropriate for this application. Instead, different metrics needed to be defined to evaluate the model performance for different hydrologic conditions and guide future re-calibration of the model.