Stream restoration is an opportunity to recover a substantial amount of lost ecosystem structure and function. This may be particularly beneficial for perennial streams in semi-arid regions because of the striking differences in productivity and biodiversity between the riparian corridor and surrounding uplands. We develop a plan to restore floodplain connectivity along a channelized reach of the unregulated Upper Gila River in southwestern New Mexico, and evaluate its potential to provide additional aquatic habitat. To identify the extent of historical channelization, primary and secondary documents are examined. Signs of current geomorphic processes are also considered to formulate a restoration design. A high-resolution elevation model of the channel and floodplain is built from Light Detection and Ranging (LIDAR) and channel survey data, and an additional elevation model is created that includes the restoration plan. The plan consists of a new overflow channel in the disconnected floodplain, and is evaluated using a hydraulic model of open channel flow built with stream geometry information from the georeferenced elevation model. Flow levels for the study are chosen and characterized based on the 83-year record of daily mean discharge measured at the gaging station immediately upstream of the study site. The hydraulic simulation estimates for total area, total volume, and patterns of inundation in the study reach are used to evaluate the change in aquatic habitat availability and floodplain connectivity for the restoration plan. Results show that the reconfigured channel pattern would provide unique backwater habitat in the reach, and it also would increase total flooded area and floodplain connectivity throughout the entire range of modeled discharges.
Stream restoration--Gila River (N.M. and Ariz.), Floodplain management--Gila River Watershed (N.M. and Ariz.)
Scherff, Eric. "Channel rehabilitation to increase aquatic habitat and reestablish floodplain connectivity on the Upper Gila River." (2012). http://digitalrepository.unm.edu/wr_sp/56