Developing Low-cost, Effective Methods for Evaluating Aquatic Ecosystems

Project ID: 101
Principal Investigator: Mark Nelson
Research Topic: Water Quality
Funded Fiscal Years: 2004, 2005, 2006, 2007 and 2008
Keywords: None

Research Question

Water project operations can cause positive or negative changes in aquatic ecosystems. Development of rapid, low-cost bioassessment techniques would be useful to detect changes and determine appropriate project operation and water release patterns. Water managers wish to predict how far biological attributes can be altered from their natural state, before an impact occurs.

* What are the impacts of operations and what type of information can be used to support biological needs and assist managers by reducing conflicts between environmental needs and project use?

* Can increased supplies be realized as water releases are often overallocated due to uncertainty? Invertebrate resources may provide useful metrics for measuring these changes.

Need and Benefit

Studies will provide information to stakeholders on integrating and enhancing aquatic system attributes during water management.

Butterfly studies will ameliorate concerns with salt cedar control used to increase water delivery. Large amounts of salt cedar cover riparian lands, causing an annual water loss estimated to be as great as 2.5 million acre-feet per year. Biological control of salt cedar is one of the tools being developed to reduce water loss; however, before control organisms can be released on a wide scale it is necessary to collect information on salt cedar control efforts on native wildlife.

Salmon redd ecology studies will determine minimal flows for egg survival and maximize water resources for stakeholders in the Yakima area.

Litter processing data will provide flood levels for decomposition and for managing treatment wetland biomass to improve reliability. Treatment wetlands need to be taken off-line when biomass from senescent plants increases to the point where treatment is compromised. Removal of biomass costs up to $100, 000 every three years. Information on decomposition rates and conditions needed to encourage invertebrate decomposers will aid in improving infrastructure reliability, prevent alterations in water storage from wetlands, and decrease costs. Wetland water is reused and supplied to irrigators in this cooperative venture between Reclamation and Eastern Municipal Water District in California.

Las Vegas Wash studies will track changes in water suitability via flood control structures that Reclamation is helping construct. These structures are designed to decrease water suitability problems associated with nutrients and salinity. Reclamation, as water master for Lake Mead and the Colorado River, is concerned with these constituents.

Collection of aquatic invertebrates associated with engineered structures will track positive biological changes related to Reclamation efforts. Other studies will examine changes in water systems operations and tail water quality. Development of biological metrics will aid in documenting flow goals and help manage Yakima area water resources in a way that will increase water reliability. This will pre-empt litigation and aid in protection of the five hundred million dollar annual crop value in the Yakima area. Study goals include improvements in infrastructure reliability, river operations, and water delivery. Information gained should be generalizable to other Reclamation projects with similar problems.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Independent Peer Review

The following documents were reviewed by qualified Bureau of Reclamation employees. The findings were determined to be achieved using valid means.

Biological Indicators Of Conditions Below Dams In The Western United States (final, PDF, 301KB)
By Mark Nelson
Publication completed on April 10, 2009

Aquatic macroinvertebrates were collected below 43 Reclamation dams in the western United States. Multivariate analysis indicated that dam height was an important variable in structuring macroinvertebrate communities. Dam height represents a multitude of impacts which includes those related to temperature and thermal regime modification,
sediment transport, hydraulic residence time, and water quality.

Restoring habitat for riparian birds in the lower Colorado River watershed: An Example from the Las Vegas Wash, Nevada (final, PDF, 595KB)
By Mark Nelson
Publication completed on October 18, 2011

The success of riparian restoration projects in the arid southwestern U.S. is often measured in terms of
vegetation characteristics such as growth, cover, and structure. Among low-elevation riverine environments
within the Colorado River watershed, restoration is typically conducted to improve degraded
habitats for birds of conservation concern by replacing the exotic tamarisk (Tamarix ramosissima) with
native cottonwoods (Populus spp.) and willows (Salix spp.). The working assumption for ma

Not Reviewed

The following documents were not reviewed. Statements made in these documents are those of the authors. The findings have not been verified.

Response of stream macroinvertebrate assemblages to erosion control structures in a wastewater dominated urban stream in the southwestern U.S. (final, PDF, 572KB)
By Mark Nelson
Publication completed on May 11, 2011

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Last Updated: 6/22/20