Chapter 11 -- National Handbook of Recommended Methods for Water Data Acquisition

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Offstream water use occurs when water is diverted or withdrawn from a surface- or ground-water source and conveyed to the place of use. After use, the wastewater is conveyed to either a wastewater treatment facility or is returned directly to the hydrologic system. Instream use occurs when the water remains in streams (surface water) and aquifers (ground water) during use, such as in hydroelectric power generation. Water use, both instream and offstream use, is represented schematically in figure 1. Although there may be considerable variation in how water is used, there are basic similarities for determining the volume or rate of use. A first step in determining water use is to define the approach needed to meet the objectives. This first or planning stage takes into account required level of detail, time and manpower available, characteristics of the types of users, and availability of water-use data from other sources. Once the approach has been determined, methods can be selected to collect the data in the most accurate and efficient manner possible. The following sections will discuss water-use concepts, general approaches, and specific methods for determining water use.

11.B.1. Concepts

Generally, water use is divided into two types: offstream use (fig. 1) and instream use. Offstream use involves the withdrawal or diversion of water from a source, treatment, distribution, and use; and the collection, treatment, and return flow of wastewater. Instream use is water that is used, but not withdrawn, from a surface- or ground-water source. The relations between the water-use processes are illustrated in figure 2.

11.B.2 Approaches

Water use can be determined either for site-specific facilities or for categories of water use for a given area. Determining site-specific water use involves water withdrawal, delivery, release, and return-flow data. Area estimates are based on coefficients relating water use to another characteristic, such as number of employees, and applying it to an inventory of site-specific users or by measuring a statistical sample of the user population.

Choosing whether to use site-specific data or area estimates to estimate water use will depend on the objective of the water-use data collection; availability of statewide reported data; availability of time, manpower, and funds; and the area to be covered. The objective of the water-use data collection determines the required degree of accuracy and reliability and identifies individual data elements that are relevant. For example, if the objective of a water-use study is to compare the need for water by the textile industry with the need for water by the petroleum-refining industry in the United States, an estimate based on a coefficient per textile or petroleum-refining employee and the number of textile or petroleum-refining employees could be used. Similarly, if the objective is to determine withdrawals by people with their own wells for each county in a State, a coefficient of water use per person per day (per capita) could be used. However, if the objective is to determine industrial withdrawals within a small watershed, then either a complete inventory or a statistical sample of the industries would be required.

Area estimates are determined by using coefficients relating water use to another characteristic that is available for the area of interest, such as people per county or specific types of industry per state. Livestock water use almost always is estimated from published livestock surveys and established coefficients for water used by dairy cattle, beef cattle, sheep, pigs, and other livestock. Coefficients are most reliable when they are applied to uniform groups of users from which the coefficients were developed, such as livestock water use.

Applying coefficients to groups of users that are non-uniform, such as industries, must be approached cautiously. Water use by specific types of industries varies widely because of age and condition of the plants, processes used, the amount of recycled water used at each plant, and quality of the cooling water (James and others, 1980, p. 5). Any coefficients used for non-uniform users, however, can be improved locally through field verification of large facilities in the area of interest.

An inventory of all users, either by mail or site visit, is feasible if there are only a few users in the category of interest, such as thermoelectric facilities; available resources or time and manpower are relatively abundant; or the area to be covered is small. Even if an inventory of reported data is available, the accuracy of the data must be investigated.

The objective of statistical sampling is to collect information on a small but representative segment (sample) of a population and generalize the results to the total population. Statistical sampling methods are used to make an inference about groups of water users and their water-use characteristics on the basis of information obtained from a relatively small number of users. If done appropriately, the results of the sample can be used to develop a coefficient to apply to the population of users. Statistical sampling can decrease the cost of data collection and still maintain reliable estimates of water use. More accurate data collection from each site is feasible if fewer sites are sampled and time is spent collecting detailed water-use information on how the water is used rather than merely collecting data on the rate of withdrawal of use.

Stratified-random sampling is one form of sampling that offers considerable efficiency in water-use estimation and involves separating sites with similar water-use characteristics into groups or strata. Stratified-random sampling can increase the reliability of estimates on the basis of sample "means." The technique is used when there are known groups with particular water-use characteristics (for example, corn or tobacco growers, motels with swimming pools and restaurants, or golf courses). Stratification divides the population into internally similar groups. The greater the internal similarity of a group, the smaller the sample needed to adequately characterize water use for the group. Sampling a larger percentage of the major users than the minor users improves the reliability of the overall water-use estimates.

Selected statistical methods for estimating ground-water withdrawals were analyzed by Luckey. He determined that regression analysis and random sampling maintained an acceptable degree of accuracy and markedly decreased data collection. Statistical methods to estimate historical and 1980 irrigation requirements in the High Plains of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming were successfully applied by Heimes and Luckey (1982, 1983). Shoemyen (1979) presented a detailed description of the statistical sampling techniques used in the Suwannee River Water Management District.

11.B.3. Methods

Methods used to determine water use are the following: (1) collection of data from the field (primary data acquisition); (2) compilation and evaluation of measured or estimated data sent by water users to State and Federal agencies (secondary data acquisition); or (3) derivation of data through the use of coefficients, accounting methods, or models (table 1). This section provides a basic description for using and evaluating the reliability of each of these methods for all major categories of water use.

11.B.4. Data management

Data management is an essential part of water-use data collection, compilation, analysis, and use. Data that are carefully automated and managed can continue to be used for decades with little additional effort. Data that are less carefully stored may become useless soon after collection. Plans should be made for data storage at the same time as data collection to ensure that all required data are collected, given appropriate identification and geographic and hydrologic references, and are properly documented. Water-use data can be stored in site-specific or aggregate data bases or in a combination, depending on project requirement. A good water-use data base ensures proper organization of the data in a readily accessible, readable, and transferable format.

There are several different groups of water-use data; (1) identification, (2) geographic, (3) hydrologic, and (4) rate or volume. Identification data include the name, address and identification (ID) numbers that tie together different data sets by using the permit numbers or other unique numbers assigned to users by different data collectors. Geographic information are imperative when a Geographic Information System (GIS) is used. A latitude-longitude coordinate precisely locates the user or other point of interest and identifies the county, MCD, State, and watershed in which the user is located.

Hydrologic information identifies the resources affected, such as the river, watershed, or aquifer. Withdrawals from each principal aquifer in an area is often useful information. Data on withdrawal sites, such as drillers' well logs, may be available from the USGS ground-water files in State District offices. Information also may be available from State pollution control agencies or State public health agencies.

Water-use data can be collected in several different units. Volume measurements are usually combined with a time interval. Million gallons per day (Mgal/d) are frequently used in the East along with million gallons per year (Mgal/yr). Acre/feet per year are used more frequently in the West. Public water supply and wastewater-treatment facilities may also use average daily demand (ADD) and maximum daily demand (MDD) in million gallons per day. Meter readings are frequently in thousand gallons or 100 cubic feet. Water-use data are most often expressed as a rate of use: a volume over time. The objective of the water-use collection will determine the importance of the time interval. Water use can be expressed as an annual total in million gallons or acre-feet. More frequently, it is expressed as a daily rate. This daily rate represents the annual volume divided by 365 days, or a maximum daily rate during a shorter period of time, for instance, a summer month, or a peak daily rate.

Establishment of good water-use data bases does not need to be the responsibility of a single agency. Coordinating committees and working groups can work toward establishing statewide or basinwide computerized data bases. The data base can be developed, updated, and accessed by all agencies requiring the information. All updates can be coordinated through and certified by the coordinating committee.

11.B.5. Quality assurance

Calibration of water-use estimates is an essential step in the quality assurance of water-use data. Care must be taken to be sure that water use estimated through the use of coefficients, accounting methods, and models are applicable to local conditions and variability.

Quality assurance is important for all data collection, compilation, analysis, and use of water-use data. Each of the previous sections on water-use determination in this chapter discuss the weakness of the different determination methods. Metered data must be reviewed in the context of the meter accuracy and reliability. Coefficients need to be calibrated to local conditions. Calibration doesn't always require the collection of site-specific data, but may be accomplished by using corroborative data, as well as statistical analysis of the range and standard deviation to identify outliers or inconsistent data. Edit programs can be written to check the reliability of automated data and identify any discrepancies from one year to the next.

11.B.6. General selected references

These general references are for general water use information. Subsequent reference sections will provide references for specific categories of use and will not duplicate references in this section.

American Water Works Association, 1986, Water meters--Selection, installation, testing and maintenance: Manual M6.

American Water Works Association and Water Environment Federation, 1994, Proceedings of the Water Reuse Symposium, Feb 27-March 2, 1994, Dallas, Tex.:, 845 p.

Anderson, K.E., 1966, Water well handbook (4th ed.): Water Well Drillers Association, Rolla, Mo., 281 p.

Arvin, Don, 1992, Feasibility of using portable, noninvasive pipe flowmeters and time totalizers for determining water use: U.S. Geological Survey Water-Resources Investigations Report 91-4110, 65 p.

Bayha, Keith, 1978, Instream flow methodologies for regional and national assessments, Instream Flow Information Paper: No. 7, Fort Collins, Colorado: U.S. Fish and Wildlife Service, Office of Biological Services, Western Energy and Land Use Team, Cooperative Instream Flow Service Group; FWS/OBS-78/61; 97 p.

Brown, T.C., Taylor, J.G., and Shelby, Bo, 1991, Assessing the direct effects of streamflow on recreation: A literature review: Water Resources Bulletin, American Water Resources Association Paper no. 91122.

Canadian Government Publishing Centre, 1986, Canada water year book, water use edition: Ottawa, Canadian Government Publishing Centre Supply and Services, 98 p.

Cordes, E.H., 1984, Ground water instrumentation program of the U.S. Geological Survey: Ground-Water Monitoring Review, v.4, no. 4, p.103-114.

Davis, W.Y., Rodrigo, D.M., Opitz, E.M., Dziegielewski, Benedykt, Baumann, D.D., and Boland, J.J., 1991, IWR-MAIN water use forecasting system, version 5.1--users manual and system description, consultant report:, Carbondale, Ill., U.S. Army Corps of Engineers and Planning and Management Consultants, 307 p.

Gleick, P.H., 1993, Water in crisis, A guide to the world's fresh water resources: New York, Oxford University Press, 473 p.

Heimes, F. J., and Luckey, R.R., 1980, Evaluating methods for determining water use in High Plains in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming, 1979: U.S. Geological Survey Water-Resources Investigations 80-111, 118 p.

-----1982, Methods for estimating historical irrigation requirements from ground water in the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Water-Resources Investigations Report 82-40, 64 p.

-----1983, Estimating 1980 ground-water pumpage for irrigation on the High Plains in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Water-Resources Investigations Report 83-4123, 36 p.

Helm, W.T., ed., 1985, Glossary of stream habitat terms: Western Division, American Fisheries Society, 34 p.

Holland, T.W., 1992, Water-use data collection techniques in the Southeastern United States, Puerto Rico, and the U.S. Virgin Islands: U.S. Geological Survey Water-Resources Investigations Report 92-4028, 186 p

Holland, T.W., and Baker, N.T., 1993, Evaluation of pumpage data furnished by selected public water suppliers in Arkansas, May 1990 through March 1991: U.S. Geological Survey Water-Resources Investigations Report 93-4104, 80 p.

Horn, M.A., Craft, P.A., and Bratton, Lisa, 1994, Estimation of water withdrawal and distribution, water use, and wastewater collection and return flow in Cumberland, Rhode Island, 1988: U.S. Geological Survey Water-Resources Investigations Report 93-4023, 54p.

Hurr, R.T., and Litke, D.W., 1989, Estimating pumping time and ground-water withdrawals using energy-consumption data: U.S. Geological Survey Water-Resources Investigations Report 89-4107, 27 p.

International Great Lakes Diversions and Consumptive Uses Study Board, 1981, Great Lakes diversions and consumptive uses: Windsor, Ontario, Canada, International Joint Commission, 56 p.

International Joint Commission, 1985, Great Lakes diversions and consumptive uses: Windsor, Ontario, Canada, International Joint Commission, 82 p.

James, I.C., II, Kammerer, J.C., and Murray, C.R., 1980, How much water in a 12-ounce can? A perspectqive on water-use information: Pamphlet reprint from U.S. Geological Survey Annual Report, fiscal year 1976, 18 p.

Kammerer, J.C., 1982, Estimated demand of water for different purposes, in Water for human consumption, man and his environment: International Water Resources Association, Dublin, Tycooly International Publishing Limited, 606 p.

LaTour, J.K., 1991, Determination of water use in Rockford and Kankakee areas, Illinois: U.S. Geological Survey Water-Resources Investigations 90-4166, 79 p.

Luckey, R.R., 1972, Analyses of selected statistical methods for estimating ground-water withdrawal: Water Resources Research, v. 8, no. 1, p. 105-210.

Mather, J.R., 1984, Water Resources: Distribution, use, and management, John Wiley and Sons and W.H. Winston and Sons, Silver Spring, Md., 439 p.

National Water Use Information Program, 1994, A supplementary guide to using the IWR-MAIN water use forecasting system with special case study. Emphasis on the MWD-MAIN version: University of Wyoming in cooperation with the U.S. Geological Survey.

Schefter, J.E., Moody, D.W., 1981, Water use data--who needs it: Water Resources Bulletin, v. 17, no 6, 978 p.

Shoemyen, J.L. (ed.), 1979, Procedure for assessing agricultural water use: Suwannee River Water Management District, Department of Planning and Operations, 114 p.

Solley, W.B., Pierce, R.R., and Perlman, H.A., 1993, Estimated use of water in the United States in 1990: U.S. Geological Survey Circular 1081, 76 p.

Sudman, Seymour, 1976: Applied sampling: New York, Academic Press, Incorporated, 249 p.

Sweat, M.J., Van Til, R.L., 1988, Water use and methods of data acquisition in Michigan, in Symposium on Water-Use Data for Water-Resources Management, Tucson, Ariz., 1988, Proceedings: American Water Resources Association, TPS-88-2, p. 872.

Tate, D.M., 1990, Water demand management in Canada--a state-of-the-art review: Environment Canada, Social Science Series no. 23, 52 p.

U.S. Bureau of Reclamation, 1974, Water measurement manual: Denver, Co., U.S. Bureau of Reclamation, 327 p.

U.S. Department of Agriculture, 1989, the Second RCA appraisal: Soil, water, and related resources on nonfederal land in the United States; Analysis of Condition and Trends: 280 p.

U.S. Environmental Protection Agency, 1993, Guide to Federal water quality programs and information: Washington D.C., EPA-230-B-93-001, 194 p.

U.S. Office of Management and Budget, 1987, Standard industrial classification manual, 1987: U.S. Government Printing Office, 705 p.

Van Der Leeden, Frits, Troise, F.L., and Todd, D.K. (eds.), 1990, The water encyclopedia (2d ed.): Chelsea, Mich., Lewis Publishers, 808 p.

Wilson, B.C., 1992, Water use by categories in New Mexico counties and river basins, and irrigated acreage in 1990: New Mexico State Engineer Office, Technical Report 47, 141 p.

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