Environment

in the gunnison basin

Environmental Issues in the Gunnison Basin

Similar to other river basins across the globe, the Gunnison River Basin faces a complex set of environmental issues. For water users, these issues might be simplified down to three particular areas:

1. Water quantity,
2. Water quality and
3. Associated impacts to fish and wildlife habitat.

In general, there are regulations associated with each of these three topics that include requirements, agreements and voluntary actions. These are primarily associated with, but are not limited to, the Endangered Species Act (ESA) and the Clean Water Act (CWA).

Water users in the Gunnison Basin are actively complying with both of these federal programs.

In very generalized and simplified terms, water quantity impacts to the environment are primarily assessed and evaluated based upon ‘depletions’ under the ESA. These depletions are related to the consumption of water by humans and include all uses. Agricultural uses causes the most depletions through evapotranspiration, this is the portion of diverted water that is consumed by the crops and that which does not return to the river system via return flows. Some estimate agricultural consumption to be about three quarters of all depletions. Municipal and industrial depletions are much smaller because the majority of diverted water for these uses are not consumed and return to the river system via wastewater treatment plants.

Depletions can affect threatened and endangered fish species, including the Colorado pikeminnow and razorback sucker. These species occupy federally-designated critical habitat in the Lower Gunnison River downstream of the confluence of the Uncompahgre and Gunnison Rivers near Delta, Colorado. In addition, there are several ‘species of special concern’, including the flannelmouth sucker, roundtail chub and the bluehead sucker. These species are subject to a multi-state “range-wide conservation agreement and strategy agreement”, and occupy much of the Lower Gunnison River Basin below the Aspinall Unit reservoirs.

In addition, water use can cause unintended consequences to water quality in the Gunnison River Basin generally related to the fact that return flows have a different character than the original water quality that was diverted for use.

Several important programs operate to protect water quality and to provide regulatory compliance and therefore certainty for water users. These include the Selenium Management Program and the cooperative Salinity Control Program.

More information / resources on environmental issues:

http://www.usbr.gov/uc/progact/salinity/

http://www.coloradoriverdistrict.org/supply-planning/endangered-fish-recovery-program/