An evaluation of the crest-stage gage program in Louisiana

The crest-stage gage program in Louisiana was evaluated to determine if the data were adequate for use in developing regional flood-frequency equations and to determine if any crest-stage gages could be discontinued. An abundance of data at many crest-stage stations and a lack of data for urban area and flat-slope areas indicated a need for a shift in the number, type, and locations of gages. Extensive correlations and comparisons of annual peak flows and watershed characteristics of 96 sites resulted in a reduced network of 25 stations that could potentially be used as index sites. The adequacy of the reduced network for development and verification of regional flood-frequency equations was tested by comparing a set of regional flood-frequency equations developed using data from the full network with a set developed using data from the reduced network. The results indicate that the crest-stage gage network can be reduced to 25 stations and still provide adequate information for future flood-frequency analyses. (USGS)