CONSIDERATIONS WHICH APPLY TO ALL WATER USE DATA:
1. Use caution when comparing water use between jurisdictions and basins because:
- financial support for data collection responsibilities varies from one jurisdiction to another;
- data collection and reporting methods are not uniform between jurisdictions;
- water use measurement tools vary from one jurisdiction to another;
- topographical features, soil characteristics and precipitation patterns--all of which affect water usage--are not uniform across the basin;
- many jurisdictions are not able to collect data from every water user.
2. There may be small differences between values produced by a self-generated query (using the CREATE YOUR OWN QUERY tab) and a table downloaded in .PDF format (using the DOWNLOAD ANNUAL REPORTS IN .PDF tab) because of independent rounding or conversion between gallons and liters.
3. Self-generated queries (using the CREATE YOUR OWN QUERY tab) present data from all facilities. Tables downloaded in .PDF (using the DOWNLOAD ANNUAL REPORTS IN .PDF tab), shows data for all facilities as well as principal facilities (a subset of all facilities which includes only those withdrawing an average of over 100,000 gallons per day).
4. Consumptive use values are usually not measured; they are arrived at by multiplying the withdrawn amount by an agreed-upon percentage (the consumptive use coefficient) for each water use category. For example, all water withdrawn for hydroelectric use is assumed to be returned to the basin, so this water use category is assigned a consumptive use coefficient of 0%. Water withdrawn for irrigation is assumed to be almost entirely lost to the basin, so this water use category is assigned a consumptive use coefficient of 70% to 90%, depending on the jurisdiction. Refer to the Consumptive Use Coefficients chart for the percentages used by each jurisdiction.
Consumptive Use Coefficients
Water Use Category Definitions
General Definitions and Abbreviations