Dissolved Oxygen, Stream Temperature, and Fish Habitat Response to Environmental Water Purchases

Peer Reviewed: 
Yes
What level of funding support did EPSCoR provide for this publication?: 
None
Date Submitted: 
2016-11-01
Date of Publication: 
2018-01
NSF Acknowledgement: 
Not Acknowledged

Environmental water purchases are increasingly used for ecological protection. In Nevada's Walker Basin (western USA), environmental water purchases augment streamflow in the Walker River and increase
lake elevation of terminal Walker Lake. However, water quality impairments like elevated stream temperatures and low dissolved oxygen concentrations also limit ecosystems and species, including federally-threatened Lahontan cutthroat trout. In this paper, we prioritize water volumes and locations that most enhance water quality for riverine habitat from potential environmental water rights purchases. We monitored and modeled streamflows, stream temperatures, and dissolved oxygen concentrations using River Modeling System, an hourly, physically-based hydrodynamic and water quality model. Modeled environmental water purchases ranged from average daily increases of 0.11e1.41 cubic meters per second (m3/s) during 2014 and 2015, two critically dry years. Results suggest that water purchases consistently cooled maximum daily stream temperatures and warmed nightly minimum temperatures. This prevented extremely low dissolved oxygen concentrations below 5.0 mg/L, but increased the duration of moderate conditions between 5.5 and 6.0 mg/L. Small water purchases less than approximately 0.71 m3/s per day had little benefit for Walker River habitat. Dissolved oxygen concentrations were affected by upstream environmental conditions, where suitable upstream water
quality improved downstream conditions and vice versa. Overall, this study showed that critically dry water years degrade environmental water quality and habitat, but environmental water purchases of at least 0.71 m3
/s were promising for river restoration.

Publication Type: 
Journal Article
DOI: 
10.1016/j.jenvman.2017.04.016
EPSCoR Acknowledged : 
No
Journal, Book, Magazine or Newspaper Name: 
Journal of Environmental Management
Volume: 
197
Pages: 
559-570
Status: 
Published
Are you collecting Data?: 
No
Non-EPSCoR Authors: 
Nate Mouzon, Logan, Elmore