The Bernalillo Reach of the Middle Rio Grande spans about 16 miles from Highway 550 Bridge to Montano Bridge Crossing in Albuquerque, New Mexico. The analysis of spatial and temporal trends in channel geometry and morphology are reported including dynamic hydrologic and hydraulic changes over the past century. The mean annual discharge has decreased since the 2000’s and the suspended sediment discharge has been declining since the 1970s, resulting in channel degradation. A GIS analysis of maps and aerial photographs dating as far back as 1918 shows geomorphic changes where the channel width has decreased from about 1,170 to about 290 ft wide, it is now about 1/4thof the historical width. Upstream dam construction in the 1970’s has led to channel incision ranging from about 3 to 8 ft. Channel planform has changed from a braided highly mobile sand bed condition to a narrow single thread gravel-dominated channel bed. There is also a slight increase in flow depth, velocity, median bed grain size and sinuosity while the slope decreased from 1972 to 2012. To further understand the channel evolution, a geomorphic conceptual model based on Massong et al. (2010) and modified by Schied et al. (2022) was considered.
