El Chausse Wetland Restoration: Design Development & Implementation

The El Chausse Concession Area is an approximately 160-acre site located on a historic meander of Reach 4 of the Colorado River, near Francisco Murguía, B.C., Mexico. Restauremos el Colorado, A.C., in partnership with Pronatura Noroeste, A.C., is implementing a project to improve and restore native aquatic, wetland, riparian, and upland vegetation to a site dominated by salt cedar and phragmites. The project is designed to capitalize on floodwaters of the Colorado River and allocated irrigation water delivered through existing canals to support a mosaic of newly planted backwater wetlands, cottonwood-willow gallery forests, mesquite bosques, and upland habitats. In addition to restoring native ecosystems, the projects will bolster the economies of nearby farming communities and ejidos through job creation. Restoration activities include: selective hand and mechanized clearing of invasive reeds and salt cedar while leaving existing native trees, earthwork/re-contouring to optimize water use and habitat, installation of infrastructure to allow for managed flooding, and planting with native cottonwoods-willow, marsh plants, upland grasses, and honey mesquite. The restoration design is expected to attract native and migratory birds and wildlife species.

The following is a summary of Oxbow Ecological Engineering’s technical contribution to the project:

Conceptual Plan Development – Oxbow Ecological Engineering processed USGS/USBR LIDAR point cloud data that was collected for entire Colorado River Delta and extracted 20 million “bare earth” points for the El Chausse Concession Area. The bare earth points were combined with RTK GPS bathymetric data, collected by OEE during ground-truthing operations, to create an existing ground surface model (TIN-Triangulated Irregular Network) for the site. This surface model was then leveraged to complete a wide array of analyses, calculations, and mapping including: habitat and water optimization, conceptual habitat maps, water extent and depth maps, and preliminary plan quantities for earthwork and plants. This concept was then presented to project cooperators in Mexicali, Mexico.
Wetland Design – Provided analysis for the grading and water control plan including earth balance calculations for embankments and habitat channel excavations, technical guidance on cast-in-place water level control structures, and the development of preliminary seasonal water maintenance hydrographs.
Construction Packages – Coordinated and collaborated with the local contractor/engineer, Estudios, Proyectos, y Construcciones del Colorado (E.P.Y.C.), on the development of project specifications, drawings, calculations, and quantity take-offs for the habitat re-contouring and and water level control structure plans.
Revegetation Plan Collaboration – Coordinated and collaborated with Fred Phillips Consulting, Inc., as needed, as part of the development of the grading and revegetation plan.
Construction Phase Services – Collaborated with Fred Phillips Consulting on Pre-bid and Pre-Construction meetings and site visits, construction observation activities, and re-vegetation workshops.