Paleoflood hydrology of the Carson River, Nevada and California

Paleoflood information establishes the long-term context of short hydrological records thereby reducing uncertainty in frequency predictions for regulatory (i.e. 100-year) floods. Three field sites along the Carson River were selected for paleoflood analysis. Results indicate a 1,600 m3s -1 magnitude flood has not occurred on the main stem in the past 1,350 years and that only three floods comparable to the 1997 event, the largest in the gage record, have occurred since and including 1862. Paleoflood evidence also suggests only four floods comparable to the 1997 event have occurred in the past 650 years on the East Fork and a flood of magnitude 630 m3s-1 has not occurred there in the past 540 years. This paleoflood data was combined with stream gage records for flood frequency analysis resulting in a return period for the 1997 flood to be 73 years on the main stem and 72 years on the East Fork.