By Connie Maxwell, NM WRRI Graduate Research Assistant
The New Mexico Environment Department (NMED) awarded the New Mexico Water Resources Research Institute (NM WRRI) a Watershed Implementation grant funded by the Environmental Protection Agency Clean Water Act Section 319 , The Rincon Subbasins 319 Project. NM WRRI, in collaboration with the Stormwater Coalition, will work to bring the best science to better understand watershed dynamics develop tools for land managers to achieve watershed restoration to address regional flooding and water supply challenges. The NM WRRI is the grant recipient and project lead; other project collaborators include the Doña Ana County Flood Commission as the long-term manager of the project and member of the steering committee, the Elephant Butte Irrigation District, Bureau of Land Management, the Caballo Soil and Water Conservation District, and additional project experts as key personnel.
Floods scour soils and transport sediment, which in turn clog downstream riparian areas, agricultural infrastructure, and overwhelm downstream flood control infrastructure. A root cause of flooding is vegetation loss in the uplands exacerbated by droughts, growing aridity, and land management. The Rincon Subbasins 319 Project implements a watershed restoration plan in two subbasins of the Rincon Arroyo Watershed with the primary objective to reduce sediment transport that includes E. coli to the impaired reach of the Rio Grande through slowing flood flows and spreading them across the landscape. This project will examine restoration and management approaches that exploit storms that come in fewer and more intense events to achieve revegetation (Bestelmeyer et al. 2018; Holmgren et al. 2006). The restoration design was informed by the results from an innovative ecohydrologic modeling framework developed by Maxwell et al. (2020) that quantified the extent of restoration needed to build the watershed’s buffering capacity to disturbances such as flooding and droughts. The small-scale, low impact restoration practices will include constructing stone lines along contours, wire and brush lines along contours,f microcatchments, and one-rock dams to infiltrate storm runoff in two sub-watersheds totaling 180 acres. The project will compare flow dynamics, E. coli loading, and vegetation between treated and non-treated control subbasins to quantify and compare the effects of the restoration practices. The collaborative process and critical science provided by this project will support water managers and inform other projects across regional watersheds of the Hatch and Mesilla Valleys.
References:
Bestelmeyer, B. T., D. P. Peters, S. R. Archer, D. M. Browning, G. S. Okin, R. L. Schooley, and N. P. Webb. 2018. The grassland–shrubland regime shift in the southwestern United States: Misconceptions and their implications for management. Bioscience 68:678-690.
Holmgren, M., P. Stapp, C. R. Dickman, C. Gracia, S. Graham, J. R. Gutiérrez, C. Hice, F. Jaksic, D. A. Kelt, and M. Letnic. 2006. Extreme climatic events shape arid and semiarid ecosystems. Frontiers in Ecology and the Environment 4:87-95.
Maxwell, C.M., Fernald, A., Cadol, D., Faist, A.M., King, J.P., (in press) 2020. Managing flood flow connectivity to landscapes to build buffering capacity to disturbances: an ecohydrologic modeling framework for drylands. Journal of Environmental Management.