Publication
Increasing Trends in Peak Flows in the Northeastern United States and Their Impacts on Design
With Richard M. Vogel. 2nd Joint Federal Interagency Conference, Las Vegas, June 27 to July 1, 2010.
- Author
- Meghan Walter
- Year
- 2010
- Topics
- Source
- See the link at the end
Water infrastructure is designed on the assumption that annual peak flows are stationary. This paper tests that assumption at every gaged river in the northeastern United States rather than only at undisturbed basins. From a database of 1,312 USGS gages with at least 20 years of record, a parametric t-test on the slope of log annual peak flow against time found positive trends at 258 gages, about one in five, concentrated in urbanized watersheds.
The paper then asks what those trends mean for design. Decadal magnification factors project how flood magnitudes grow, and recurrence reduction factors translate that into return periods. If the observed trends continue at the trending sites, in ten years the 10-year flood becomes on average a 6.1-year event, the 25-year flood a 13.8-year event, and the 100-year flood a 48.5-year event. Under Bulletin 17B, an unrecognized nonstationary signal biases flood frequency low and leads to undersized bridges, culverts, and dams. The findings show remarkably large trends at a small share of sites.
Details
AuthorsMeghan Walter, NRCS; Richard M. Vogel, Tufts UniversityVenue2nd Joint Federal Interagency Conference on Sedimentation and Hydrologic ModelingWhere and whenLas Vegas, Nevada, June 27 to July 1, 2010FormatConference paper, PDF
The original ACWI link no longer resolves. The paper is preserved in the Internet Archive.