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2 Gaging the Nation's Streams
Pages 19-46

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From page 19...
... In this chapter, the committee traces the history of river studies and streamgaging at the USGS, summarizes what a USGS gaging site generally looks like, briefly consider the role of other U.S. agencies in supporting streamgaging, looks at streamflow network design in other countries, and examines the value of a national streamflow information program.
From page 20...
... A small appropriation in 1894 was earmarked for "gauging the streams and determining the water supply of the United States." Groundwater and water-use investigations became part of the USGS, and appropriations were increased regularly. The federal need for water information was fully recognized in 1896, when a Public Lands Commission was recommended, to include the director of the USGS.
From page 21...
... The USGS Hydrographic Division separated from the Geologic Branch and became the Hydrographic Branch. Appropriations increased for water resources investigations over the years, in response both to irrigation needs and to several major floods (Figure 2-2)
From page 22...
... . FIGURE 2-3 A USGS geologist surveys a western river for power generation potential in 1920.
From page 23...
... USGS scientists also studied flood hazards; water supply issues, including water resource assessments; snowpack and snowmelt, annual runoff estimates for major basins; and effects of rainfall and drought on flow.
From page 24...
... The 1960s and 1970s saw passage of the Water Quality Act, the Solid Waste Disposal Act, and the National Environmental Protection Act. By 1971, the USGS collected streamflow data at more than 11,000 gaging stations and measured water quality at 4,000 stations.
From page 25...
... Mapping advances benefited the Water Resources Division; by 1988, the Mapping Division completed the 1:100,000-scale digital database including hydrology of the United States. USGS publications from the last few decades reflect emerging technologies and changing societal values, linking streamflow to water quality, land use, and watershed management.
From page 26...
... Changes in stage originally were recorded by using a float attached to a rotating drum and, more recently, have been recorded by using pressure transducers that convert water pressure to an electronic signal. A sturdy housing protects most USGS gages; even during severe floods the gages must continue to function and transmit information or they lose their value for flood warning.
From page 27...
... As might be expected, very high stages and discharges are rare but are of great interest for flood warning. The USGS strives to amass data on high discharges whenever and wherever they occur, in order to extend rating curves into the high-flow range.
From page 28...
... Not all data are disseminated: many are archived by the USGS, either digitally or otherwise, including notes by field hydrologists, rating curves, and so-called unit values of discharge. Gaging and data retrieval innovations have led to variability among the 7000 USGS gage stations.
From page 29...
... . FIGURE 2-6 Arizona's Santa Cruz River, normally dry, in flash flood, 1983.
From page 30...
... . · Safety: need for technology to measure discharge quickly and remotely · Communications: need for information to reach the affected public quickly, despite possible interruptions in communication lines · Durability: need for gages and transmission devices to continue to function even in severe conditions · Water supply security: need for information on low-flow conditions to provide decision makers and water managers with information to manage needs for drinking water, power generation, recreation, defense, industry, and instream habitat · Distribution and coverage: need for knowledge of conditions at any time, whether measured directly or interpolated · Continuity: need for long records in order to understand extreme events and assess stationarity of streamflow · Cost optimization: need to optimize the balance between spatial coverage and long records, given that resources are limited
From page 31...
... TABLE 2-1 Summary of Hydrologic Stations a Costs Number Percentage Number Feature Active of Total Inactive Technology Labor Data collected Continuous stage 7,273 12,151 Crest stage only b b Discrete (event) data b b High Data retrieval By site visit 1,260 17.3 Low High By satellite 6,013 82.7 High Low By camera 0 0 High Low Remote sensing Ground-penetrating radar 0 0 0 High Doppler 200-300 High aThe numbers of gages recording stage maxima or discrete events are not tracked because of their inherently changing nature.
From page 32...
... Gaging is therefore an example of adaptive management, in which the fundamental goal is to obtain coverage either directly or indirectly for the priority gaging needs. ROLE OF OTHER AGENCIES IN SUPPORTING STREAMGAGING Many city, county, state, and federal agencies collect streamflow data.
From page 33...
... The bureau also provides a national flood warning service under collaborative arrangements with state or territory and local governments. As a result of these arrangements, the bureau does operate some stream monitoring stations.
From page 34...
... National streamgaging information is available on-line at the Bureau of Meteorology site as a catalog of the water quality monitoring stations operated by the state and territory water agencies. However, only descriptions of the data are provided.
From page 35...
... These are stations associated with federal responsibilities arising from international agreements, treaties, orders, or studies, including the following: · Stations specifically named under the Boundary Waters Treaty and those approved officially as "international gauging stations" · Stations specifically stipulated under International Joint Commission Orders, or required to support such orders, to provide for control of waters crossing or forming part of the international boundary and for International Joint Commission related study, surveillance, flow regulation, or apportionment purposes; such stations may also be required for similar studies carried out under unilateral or bilateral mechanisms and undertaken in anticipation of the need for formal orders · Stations related to international treaties and agreements that involve waters crossing or forming part of the international boundary and specifically stipulate the reaches of streams required to be monitored or special arrangements that have to be made to meet water quantity survey needs · Stations on streams flowing across or forming part of the international boundary for which Canada has determined that monitoring is required for water management purposes 4. National Water Quantity Inventory.
From page 36...
... United Kingdom The United Kingdom maintains a network of more than 1,300 gaging stations. Responsibility for these stations rests primarily with the Environment Agency in England and Wales, the Scottish Environment Protection Agency, and in Northern Ireland, the River Agency.
From page 37...
... The Australian case is particularly interesting because the Bureau of Meteorology provides a federal link to valuable streamflow data from states and territories. European Environmental Agency The design of a water resources monitoring network for the European Environmental Agency (EEA)
From page 38...
... statutory and operational monitoring to provide information for the business and operational needs of regulators, suppliers, and other users; and 2. surveillance monitoring to characterize and allow appraisal of the state of water resources and, with water quality and biodiversity information, the state of the EU water environment.
From page 39...
... reducing pollutant loads to waterbodies. Other areas where streamflow data can have high value include national defense, food and fiber production, recreation, and wildlife habitat and diversity including Endangered Species Act requirements.
From page 40...
... As shown in Figure 2-8, the number of flood insurance policies has increased steadily through the years; the number of damage losses paid out fluctuates significantly from year to year, averaging about 40,000 losses paid out per year in recent years; and the dollar value of these losses also varies significantly from year to year, averaging about $1 billion per year in recent years. Generally speaking, streamflow data, including data uncertainty, are necessary for rational economic decision making for flood warning (Krzysztofowicz, 1999)
From page 41...
... FIGURE 2-8 Trends through time in the National Flood Insurance Program. SOURCE: FEMA (2003; http://www.fema.gov/nfip)
From page 42...
... Water supply management during recent droughts in the western United States has strengthened the realization that more precise streamflow forecasts and predictions can partially substitute for increased structural supplies. By making better use of existing storage capacity and allowing more precise regulation of minimum streamflows to meet environmental standards, better information can substitute for structures at a substantial saving.
From page 43...
... However, these contingent transfer contracts depend on reliable forecasts of water demands under different streamflow conditions and on the ability to accurately monitor real-time streamflow conditions during droughts. Reducing Pollutant Loads to Waterbodies Water quality is also intimately linked to stream discharge and velocity, and discharge estimates are critical to accurate contaminant load estimates and pollutant reduction plans.
From page 44...
... RATIONALE FOR FEDERAL SUPPORT The rationale for the National Streamflow Information Program rests on both the value of streamflow information and the national need for this information. Streamflow information, like most goods and services, can be provided through a variety of administrative and institutional mechanisms.
From page 45...
... Information, in the form of streamflow data, has a low but measurable marginal cost of provision even with methods such as web page data download sites. It is clear that modern data access methods have significantly lowered the marginal cost of provision and, thus, made streamflow data and analysis more clearly a public good.
From page 46...
... Streamflow information supports innumerable planning, management, and scientific activities over a broad range of spatial and temporal scales. These include optimizing hydropower and water supply; reducing impacts of flooding; reducing impacts of droughts; reducing pollutant loads to water bodies; and providing for national defense, food and fiber production, recreation, and wildlife habitat and diversity, including Endangered Species Act requirements.


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