Estimating Forecast Lead Time

Flood warning systems (FWS), if properly designed and operated, reduce flood damages and save lives. For federally funded projects, the economic benefit of the FWS must be computed. That benefit must be greater than the project cost for the system to be implemented. The driving factor in the benefit computations is the duration of the lead time attributed to the FWS. In other words, how far in advance can a FWS forecast a threshold exceedence? We have developed a straightforward procedure to answer this question using standard-of-practice rainfall-runoff models. The result can be used with economic models to estimate the economic benefit of an FWS for project planning purposes.