April 2019 eNews

UNM Researcher Studies Ecological Responses in a River with More and Less Water: Chama River unrepresentative system for natural water flow

By Steve Carr, University of New Mexico Communication & Marketing

University of New Mexico graduate student Monika “Mo” Hobbs has been conducting research along the Chama River and El Vado Dam in northern New Mexico to attempt to learn how the flow of water affects invertebrates and their environment.

Last year, Hobbs received $6,000 to help fund her research titled Ecological responses in a river with more and less water: a case study of highly-managed Chama River, New Mexico as a part of the Student Water Research Grants program through the New Mexico Water Resources Research Institute.

The Rio Chama has several reservoirs and dams, including Heron Reservoir, El Vado Reservoir, and Abiquiu Lake that are essential for storing water for agriculture and residents of New Mexico, while also providing flood control services. Hobbs’ research focuses on the Chama River and the El Vado Dam and how that dam affects the physical and biological structure of a stream including the timing, magnitude, and frequency of stream discharge.

“My research integrates elements of biology, hydrology, and geomorphology,” said Hobbs, who is currently working on her Masters’ in Water Resources in UNM’s Water Resources Program. “In New Mexico, the water is more spoken for than it is present. The use of water must be allocated amongst multiple users while also trying to maintain a life for aquatic organisms and habitats.”

Usually, the amount of water released from the El Vado Reservoir is determined by the needs of downstream users, which causes the Chama River to be unrepresentative of the natural flow of water the aquatic invertebrates are used to. For example, decreased water flow can limit the diversity of aquatic organisms. Additionally, certain organisms cannot adjust well to quick and dramatic changes in water flow.

Hobbs’ research project intends to assess the responses of macroinvertebrates in a river with more and less water with the objective of informing water managers about the optimal timing of water releases to benefit both the ecosystem and downstream users. Aquatic invertebrates are a practical and effective means for measuring stream resiliency due to their essential role in aquatic ecosystems and because their community tells of ecosystem disturbance.

“The objective of my research is to consider the potential effects of variable flows on macroinvertebrate communities in the highly managed reach of the Rio Chama by gathering site-specific ecological data to help stakeholders design flow optimization targets and measure the success of their modified flow releases,” said Hobbs. “This research will involve sampling macroinvertebrates and various physical and chemical parameters that may influence the community, and performing a statistical analysis to assist in determining which parameters are most important in driving the community, and ideally what role the current managed flow regime plays.”

Operation of these hydraulic structures often leads to diminished spring peak flows, relative to pre-infrastructure. However, there is actually more water in the Rio Chama overall due to the San Juan Chama Project, where water is conveyed through the continental divide from the San Juan River to the Rio Chama, and eventually to the Rio Grande.

Hobbs’ initial interest in intentional management of water resources to increase benefits to wildlife began while doing field work in Nevada. She participated on a small mammal survey team and could see how a stream diversion, which greatly reduced streamflow, negatively impacted the community of small mammals in the area. About a year into the Water Resources Program, Hobbs was introduced to the unique streamflow patterns on the Rio Chama and the interest of stakeholders to optimize flows for the benefit of the surrounding ecosystem.

The NM WRRI provides support for water-related research through its Faculty and Student Water Research Grant Programs. Funds for the Student Water Research Grant Program are made available through the institute’s state appropriations. The funded projects allow New Mexico university faculty and students to pursue critical areas of water resources research while providing training opportunities for their students.

NM WRRI Student Water Research Grants are intended to help students initiate research projects or to supplement existing student research projects in water resources research. The research grants usually fund expenditures for student salaries, supplies, sample analysis costs, field equipment, travel to field sites, and travel to present results at professional meetings.

“The most exciting part about receiving the grant was knowing that I could actually implement my research project,” said Hobbs. “I was absolutely ecstatic when I found out I received the grant. I cannot thank the New Mexico Water Resources Research Institute enough for supporting my research and allowing me to gather data and perform analyses that contribute to an expansion of knowledge about New Mexico’s ecological resources.”