Estimating Water Use in the United States A New Paradigm for the National Water-Use Information Program (2002) / Chapter Skim
Currently Skimming:
8. Integrative Water Use Science
8. Integrative Water Use Science
Pages 130-142
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 130... ...
Water use science, therefore, must encompass and integrate both the social and natural sciences. We use the term "integrative water use science" to describe this multidisciplinary, hypothesis-driven investigation of the behaviors and phenomena that determine spatial and temporal patterns of water use, and of the impacts of water use on aquatic ecosystems, the hydrologic cycle, and the sustainability and vulnerability of the nation's water resources.
|
From page 131... ...
of irrigation water as it is diverted from a stream or reservoir or pumped from an aquifer, is applied to the land surface, undergoes evapotranspiration, leaches salt from the soil, and emerges as irrigation return flow. Water diverted for municipal consumption also generally suffers reduction in quality, as the water discharged from a wastewater treatment plant is generally "degraded" relative to the original diversion.
|
From page 132... ...
Water use causes pollutants to enter waterways other than from discrete point sources (e.g., irrigation water leaches salts from soils, causing the salts to enter surface waters and groundwaters as part of irrigation return flows)
|
From page 133... ...
, which cover about half the land area of the United States and about 60 percent to 70 percent of the nation's water use and population served by public water supplies.
|
From page 134... ...
Because the NAWQA Program does not cover the entire nation, any of its water-quality information that would be used in an expanded NWUIP would have to be augmented by data from other programs. Although much of the existing water use data are organized by political unit, it may be feasible in some cases for the NAWQA study units themselves to serve as modeling units to develop the science behind water use estimates.
|
From page 135... ...
The USBR is currently concerned with the quality of irrigation water supplied by its projects through its National Irrigation Water Quality Program (http:// www.usbr.gov/niwqp/~. Because irrigation return flow often empties into reservoirs e.g., Kesterson Reservoir in the San Joaquin Valley, whose wildlife has suffered from selenium poisoning (NRC, 1989)
|
From page 136... ...
, which has been used extensively in the NAWQA Program as a regional water-quality assessment tool, may also be useful in an expanded NWUIP. Although SPARROW was not developed under the aegis of the NAWQA Program, it has been implemented in a number of NAWQA studies.
|
From page 137... ...
Environmental and recreational interests are increasingly pursuing an agenda that includes watershed restoration and protection of instream flows to restore and sustain a stream's historic ecological and hydrogeologic functions (Tarlock, 1999~. A growing body of evidence indicates that the maintenance or restoration of whole riverine ecosystems requires a range of flow conditions, because different species have different flow optima and may be dependent on natural disturbances such as low and high flows (Poff et al., 1997; Sparks, 1992~.
|
From page 138... ...
Riparian ecosystems require instream flows different in timing and magnitude from aquatic organisms, which often differ among themselves (e.g., fish vs. macroinvertebrates)
|
From page 139... ...
This method uses measured or synthesized daily streamflow data from a period during which human alteration of the hydrologic system was negligible; this streamflow record is then characterized using 32 variables defined by Richter et al.
|
From page 140... ...
Dr. Schwarz discussed the 1978 Second National Water Assessment of the Water Resources Council, which provided an overview of the nation's 99 water resource assessment regions and of the nation as a whole.
|
From page 141... ...
Rather, it would be a tool for assessing the relevance of water use information in determining water availability in the stream, which might prove useful in estimating instream flows for ecological needs. Various sampling and other methods could be used to make independent estimates of water use in the absence of detailed water use estimates in every state.
|
From page 142... ...
Most current methods for estimating instream flows are species-specific and cannot estimate instream flow requirements for multispecies assemblages or entire aquatic/riparian ecosystems. The specter of global climate change also looms large, as it may diminish flows in already overallocated streams.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.