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<br />WSW Issue #1687
<br />September 15, 2006
<br />WATER RESOURCES
<br />Water Availability/Water Information Management
<br />On September 12 -15, the Western States Water Council, U.S. Geological Survey (USGS) and the New
<br />Mexico Office of the State Engineer (OSE) cohosted a workshop on Water Information Management Systems
<br />(WIMS) and Water Availability. It was preceded by a training session on the USGS National Hydrography Dataset
<br />(NHD), which is a comprehensive set of digital spatial data about surface water features, such as lakes, ponds,
<br />streams, rivers, and springs. When combined to form "reaches," it provides a framework for linking water - related
<br />data to the surface drainage network, and allows users to display and analyze water - related data in upstream and
<br />downstream order.
<br />The NHD is part of the USGS Mapping /Geography Division, and was initiated with $20M from USGS and
<br />the Environmental Protection Agency (EPA). It is based upon the content of USGS Digital Line Graph (DLG)
<br />hydrography data integrated with nationwide reach - related information from the EPA Reach File Version 3 (RF3).
<br />The NHD supersedes DLG and RF3 by incorporating them, not by replacing them, with a greatly expanded and
<br />refined capacity. While initially based on 1:100,000 -scale data, a $50M upgrade to a 1:24,000 scale will be
<br />completed in March 2007. The NHD is designed to incorporate and encourage the develop -ment of higher
<br />resolution data required by many users. NHD+ now provides streamflow volume and velocity data for any reach,
<br />as well as mean annual flows, time of travel and elevation grids, etc.
<br />However, USGS downsizing threatens further NHD development. Therefore, USGS is seeking to turn
<br />NHD over to states for "fine tuning," with states adding the location of gages, dams, water diversions, canal flows,
<br />fish habitat, water quality and other data. USGS would provide training support and data quality control and
<br />assurance. Pennsylvania uses NHD as its framework for determining water availability. Western states with NHD
<br />agreements in place or being negotiated include California, Colorado, Idaho, Kansas, Montana, New Mexico,
<br />North Dakota, Oregon, Utah, Washington and Wyoming. USGS asked for $1.25M in FY07 for agreements in 24
<br />states, but some $2M is needed. For more NHD information, contact Jeff Simley, USGS, at jdsimley @usgs.gov or
<br />(303) 202 -4131.
<br />On Wednesday, September 13, USGS experts from across the West addressed a variety of models and
<br />other information for projecting water supply needs and determining water availability. Rain, snow and storage are
<br />the major components of water supply in the West says George Leavesley, USGS National Research Program,
<br />Denver. The National Weather Service (NWS) and Natural Resources Conservation Service (NRCS) provide
<br />much of this information. "We all use history as an analogue for the future," said Leavesle "but the future may be
<br />very different from the past." He used as an example evidence that snowmelt and pea pring runoff are coming
<br />earlier. Water managers need to know how much water they will have Vwhen come. They have to work
<br />with uncertainty and th ere are many models that provide, high, low anasts. However, there is no
<br />one perfect model. Sometimes "ensemble modeling," using regression the mean and median from a
<br />number of models, can improve forecasts. Often the simpler models p most efficient, as the more
<br />complex a model is, the more demanding are its needs for data, maint
<br />Bill Alley, Chief, USGS Office of Ground Water, addressed issues of sustainability and the long term
<br />effects of climate change on ground water. USGS is now conducting ground water availability studies in the
<br />Denver Basin, Great Basin, and California's Central Valley. The latter ranks just behind the Ogallala Aquifer in
<br />water production. He also mentioned cooperative work in the Middle Rio Grande, involving different USGS
<br />programs. Of note, he explained that relatively small ground water depletions can have large effects. San Pedro
<br />Basin ground water use has consumed only 2% of the estimated 23 million acre -feet (Maf) in storage, but that has
<br />raised concerns over land subsidence, aquifer compaction and the loss of wildlife habitat and vegetation
<br />dependant on ground water.
<br />http: / /www.westgov.org /wswc /1687.html 10/24/2006
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