Watersheds

Las Conchas fires

Flames from the Las Conchas fire as seen from Los Alamos National Laboratory (KRQE)

The wellbeing of humankind has always been intricately tied to the resources provided by the natural environment, which are referred to as ecosystem services. Watersheds contribute to many of these services including storage and provisioning of water, baseflow augmentation through bank storage and release, flood reduction through watershed and floodplain storage and floodwave attenuation, nutrient retention and cycling, and the provision of fish and wildlife habitat. It has been widely documented that past watershed management and river engineering projects have contributed to the degradation of ecosystem services. For example, 20th Century forest management practices in the southwestern U.S. have resulted in reduced water yields and increased sediment yields.

The Rio Grande is a highly engineered river within a highly stressed watershed that has experienced severe drought over the past several years. Drought conditions in the Rio Grande Watershed are further confounded by the increased frequency and severity of forest fires and subsequent flash floods in the headwaters. Of the 20 largest wildland fires observed in New Mexico, 19 of them have occurred since the year 2000. Two of the most notable fires occurred in the Jemez Mountains, which are an important headwater region for the Rio Grande. When the Cerro Grande Fire occurred in May 2000, it was the second largest fire in New Mexico’s recorded history as it burned 190 km2 and destroyed a large portion of the City of Los Alamos. That fire was dwarfed by the 630 km2 that burned in the Las Conchas Fire in June 2011. Because the fire season precedes the monsoon season in the Southwestern U.S., these fires were both followed by catastrophic floods resulting in destruction of infrastructure including the Santa Clara and Cochiti Pueblo Indian Reservations, the City of Los Alamos, and Bandelier and Kasha-Katuwe Tent Rocks National Monuments.

Research is needed to improve the understanding of how the watershed has been affected by past practices and the best approaches for restoring the ability of watersheds to provide ecosystem services. The goal of this subproject is to enhance knowledge of the impacts of watershed management on hydrologic processes and ecosystem services within the headwaters of the Rio Grande Watershed. The team will investigate: (1) the impacts of forest management (mechanical thinning, controlled burns, etc.) on hydrologic processes in headwater watersheds, (2) the impacts of watershed management and wildland fires on nutrient processing rates, and (3) the interacting impacts between watershed management and climate change on hydrologic and biogeochemical processes in headwater watersheds.

Read more about the specific research projects being done in the CWE.