Equations for estimating the magnitude of peak discharges for
recurrence intervals of 2, 5, 10, 25, 50, 100, and 500 years were
updated for New Mexico. The equations represent flood response
for eight distinct physiographic regions of New Mexico.
Additionally, a regional equation was developed for basins less
than 10 square miles and below 7,500 feet in mean basin elevation.
Flood-frequency relations were updated for 201 gaging stations on
unregulated streams in New Mexico and the bordering areas of
adjacent States. The analysis described in this report used data
collected through 1993. A low-discharge threshold was applied to
frequency analysis of 140 gaging stations. Inclusion of these low
peak flows affects the fitting of the lower tail and the upper
tail of the distribution.
Peak discharges can be estimated at an ungaged site on a
stream that has a gaging station upstream or downstream. These
estimates are derived using the drainage-area ratio and the
drainage-area exponent from the regional regression equation of
the respective region.
Flood-frequency estimates for 201 gaged sites were weighted by
estimates from the regional regression equation. The observed,
predicted, and weighted flood-frequency data were computed for
each gaging station.
A maximum observed peak discharge as related to drainage
area was determined for eight physiographic regions in New
Mexico. Peak-discharge data collected at 201 gaging stations were
used to develop a maximum peak-discharge relation as an
alternative method of estimating the peak discharge of an extreme
event.
