Changing Middle Rio Grande Channel Conditions: Isleta to Rio Puerco

摘要

The Isleta Reach of the Middle Rio Grande spans about 42 miles from Isleta Diversion Dam to the confluence with the Rio Puerco. Analysis of spatial and temporal trends in channel geometry and morphology are reported. Hydrologic and hydraulics have been dynamic over the past century. The mean annual discharge has decreased since the 2000s, and the suspended sediment discharge has been declining since the 1970s, resulting in channel degradation. GIS analysis of aerial photographs and maps dates as far back as 1918 showing geomorphic changes; the current channel is less than one-fifth of what it was in 1918. There is also a slight increase in depth, velocity, median bed grain size, and sinuosity (channel length/valley length), while the slope decreased from 1972 to 2012.