Inner Rio Grande Valley
William Lettis & Associates (WLA), a division of Fugro Consultants, Inc., mapped surficial geologic deposits along over 105 river miles of the inner Rio Grande Valley, between Isleta Pueblo and Elephant Butte Reservoir. The mapping identified the types and distributions of floodplain sediments at two time windows: 1935 and 2001. This historical (1935) and modern (2001) data was selected for characterization and comparison of the changes to the fluvial geomorphic system and related perturbations to the floodplain linkages.
Changes imposed on the system include controlled discharge (dams), river confinement (levees), incursion of salt cedar vegetation, as well as urbanization and land use changes. The surficial geologic mapping provided key insights to early depositional environment river patterns, as well as locations of modern river sedimentation and erosion. The map data, in turn, provided a geomorphic and geologic framework for decision makers, such as floodplain restoration planners or flood managers, who are responsible for flood control or conveyance structures.
Fugro Services: Geologic mapping of floodplain sediments, characterization of geomorphic system, and system changes over time