Water Resources Research Act Program

Details for Project ID 2011NV178B

Measuring Water Use of Tamarisk and Impacts from Biocontrol: Lower Virgin River, NV

Institute: Nevada
Year Established: 2011 Start Date: 2011-03-01 End Date: 2014-02-28
Total Federal Funds: $47,206 Total Non-Federal Funds: $106,993

Principal Investigators: Kumud Acharya

Project Summary: Tamarisk species (Tamarix spp.) are one of the most successful invasive species in the western United States. With their high success rates, come several consequences. These include, but are not limited to, degradation of soil quality, high water use and loss of biodiversity. Traditional eradication efforts such as herbicidal treatment, fire and mechanical removal have either proven too costly or shown to have negative impacts on the native flora which they are intending to restore. Recently, new eradication efforts have shifted towards the use of a biocontrol agent, the saltcedar leaf beetle (Diorhabda elongata), to reduce tamarisk leaf cover along many western water sheds. The Virgin River watershed (a tributary of the Colorado River) is dominated by thick extensive stands of tamarisk and has been undergoing biological control studies since 2004. Due to the implications of possible increased water savings for Lake Mead through tamarisk defoliation, an eddy covariance (EC) tower was installed along the river in the early spring of 2010. The primary goal of the proposed research was to estimate evapotranspiration (ET) prior to and following episodic herbivory by the leaf beetle using the existing EC station. Specifically, under the proposed research plan we will 1) quantify ET prior to and following episodic herbivory by the leaf beetle, 2) calculate the difference between ET prior to and following herbivory which may contribute to a net savings of water along the Virgin River, 3) monitor temperature changes in the tamarisk stand through the use of a temperature iButton (Maxim Integrated Products) and 4) monitor stream flow and daily groundwater oscillations from groundwater wells maintaining by Desert Research Institute, Southern Nevada Water Authority, and Virgin Valley Water District. The proposed study will provide insight into the water saving potential of restoring native habitat not only for the Virgin River corridor but also for the Lower Colorado and other riparian systems infested by Tamarisk. The results will be published in peer-reviewed journals, and made available to the public, in an effort to educate on the use of biocontrol for tamarisk removal. Furthermore, the research will provide student educational opportunities on the application and use of an EC station to estimate ET. Finally, the knowledge and data gained from this study will serve to support additional proposals for national funding, so that we can further understand the effectiveness of biocontrol on water savings resulting from invasive species eradication.