SBIR-STTR Award

This proposal is directed to the development of a procedure for generating long streamflow sequences. It is proposed to first develop a long sequence of hourly rainfall by stochastic methods and to transform this rainfall sequence into streamflow with a deterministic hydrologic model. Phase I will focus on the a stochastic rainfall model capable of developing rainfall sequences at multiple sites. The work of Franz and Kelman will be the basis of this model. A 1000-yr flow sequence will be developed. The annual flood peaks will be studied to determine the best fit frequency distribution. Subsamples of 100, 200, 333, and 500 years will be analyzed to determine the variation of uncertainty in flood frequency estimates with sample size. This information will be used in planning Phase II of this research, which will require application of the methods to data from several catchments representing a variety of hydrologic regimes.Anticipated Results/Potential Commercial Applications of the Research:If the research is successful it will: 1. Help to improve present procedures for estimating flood frequency for events with 100-yr return period and less. 2. Provide a basis for estimating flood probability at probability levels of 10-3 and less. 3. Permit an evaluation of the probability of the Probable Maximum Flood currently used for spillway design.

This proposal is directed to the enhancement and testing of a procedure for generating long streamflow sequences to be used as a basis for improving flood frequency estimates. The procedure computes a long sequence of hourly rainfall data using a stochastic model developed and tested in the Phase I project. This synthetic rainfall is then transformed into synthetic streamflow using a deterministic hydrologic model. The Phase I results indicate that this procedure has significant potential for study of floods of long return period. The procedure will be applied to 4 to 6 watersheds in the United States selected to represent a range of climatic regimes. This more extensive testing will help establish the applicability and reliability of the procedure.Anticipated

Benefits:
If the research is successful it will: 1. Provide a basis for estimating flood probability at levels of 10-3 or less. 2. Permit san evaluation of the probability of the Probable Maximum Flood currently used for spillway design.