Environmental flows in the Rio Grande - Rio Bravo basin

Abstract

The Rio Grande/Bravo is an arid river basin shared by the United States and Mexico, the fifth-longest river in North America, and home to more than 10.4 million people. By crossing landscapes and political boundaries, the Rio Grande/Bravo brings together cultures, societies, ecosystems, and economies, thereby forming a complex social-ecological system. The Rio Grande/Bravo supplies water for the human activities that take place within its territory. While there have been efforts to implement environmental flows (flows necessary to sustain riparian and aquatic ecosystems and human activities), a systematic and whole-basin analysis of these efforts that conceptualizes the Rio Grande/Bravo as a single, complex social-ecological system is missing. Our objective is to address this research and policy gap and shed light on challenges, opportunities, and success stories for implementing environmental flows in the Rio Grande/Bravo. We introduce the physical characteristics of the basin and summarize the environmental flows studies already done. We also describe its water governance framework and argue it is a distributed and nested governance system across multiple political jurisdictions and spatial scales. We describe the environmental flows legal framework and argue that the authority over different aspects of environmental flows is divided across different agencies and institutions. We discuss the prioritization of agricultural use within the governance structure without significant provisions for environmental flows. We introduce success stories for implementing environmental flows that include leasing of water rights or voluntary releases for environmental flow purposes, municipal ordinances to secure water for environmental flows, nongovernmental organizations representing the environment in decision-making processes, and acquiring water rights for environmental flows, among others initiatives. We conclude that environmental flows are possible and have been implemented but their implementation has not been systematic and permanent. There is an emerging whole-basin thinking among scientists, managers, and citizens that is helping find common-ground solutions to implementing environmental flows in the Rio Grande/Bravo basin.

The dynamics of mature and emerging freshwater conservation programs

“…Such relationships are fully consistent with-and derive from-the fundamental law of demand in economics, i.e., demand for conservation programs adjusts in response to price changes (e.g., Lambert et al, 2007). To boost program participation, conservation actors should look for opportunities to leverage growing participation willingness and awareness of a number of restoration actions or policies, including those that support environmental flows (Wineland et al, 2021c;Sandoval-Solis et al, 2022), water conservation (Farzaneh et al, 2021), habitat restoration (Popejoy et al, 2018), invasive species management (Milt et al, 2018), fish passage and the restoration of ecosystem connectivity (Fleming and Neeson 2020;McKay et al, 2020). In particular, outreach and education efforts may offer low-cost means for increasing support for conservation programs (Wade et al, 2021).…”

Multi-scale drivers of daily flow intermittency in a regulated desert river

“…The Rio Grande is contained within the Rio Grande/Rio Bravo Basin (Fig. 1), which encompasses approximately 11% of the continental United States (Sandoval-Solis et al, 2022). The Rio Grande is the basin’s largest river and is noteworthy as the fifth-longest river in the United States and twentieth longest worldwide (Patiño-Gomez et al, 2007).…”

“…Nearly 83% of the basin's water resources are diverted for agriculture, suggesting that understanding how in-channel infrastructure like diversion dams control flow intermittency would contribute to efforts to develop environmental flows in this and other arid agricultural systems (Sandoval-Solis et al, 2022) Significantly, the Rio Grande is home to the endangered Rio Grande Silvery Minnow (Hybognathus amarus). When the river is diverted to provide crop irrigation, close monitoring of flow intermittency is required to support the fish's conservation (Platania et al, 2020;McKenna, 2021;Walsworth and Budy, 2021).…”

“…The Rio Grande is contained within the Rio Grande/Rio Bravo Basin (Fig. 1), which encompasses approximately 11% of the continental United States (Sandoval-Solis et al, 2022).…”

Small increases in stream drying can dramatically reduce ecosystem connectivity

“…This suggests that even small alterations of hydrologic regimes can have significant ecological consequences. Water management strategies that aim to incentivize reductions in water usage (Zamani Sabzi, Rezapour, et al, 2019) or set targets for environmental flows (Sandoval-Solis et al, 2022;Wineland, Bas ¸a gao glu, et al, 2021) should carefully consider the potential for nonlinear impacts of stream drying. In our study, stream drying is associated solely with climatic changes, and water managers should seek to identify water sustainability strategies that are robust to future climate uncertainty (Farzaneh et al, 2021;Fovargue et al, 2021;Wineland, Fovargue, et al, 2021).…”