The physical presence of water on the public lands is not always sufficient for the BLM to accomplish its mission. In the Western United States, the right to use a sufficient quantity of water for many beneficial uses is paramount in ensuring proper management of the public lands and is a necessary resource both for human use and ecosystem sustainability. Water rights are rights in real property, and can be either federally reserved rights for specific purposes identified through executive order or federal legislation, or state appropriative rights that are administered by states.
Federal Reserved Water Rights
When the United States reserves public land for uses such as Indian reservations, military reservations, national parks, forest, or monuments, it also implicitly reserves sufficient quantities of water to meet the primary purpose for which the reservation was established ("primary purpose" requirement) and only in the minimum amounts necessary to meet those purposes ("minimal needs" requirement). Therefore, it is important to quantify any federal reserved right. Generally, quantifying a federal reserved right requires specifying the amount of water claimed, the water sources, the primary purpose of the reservation for which the water is needed, and the date the reservation was created. Because the data needed to quantify the water needed is often not available, there can be controversy regarding the quantity claimed, but generally not regarding the assertion of a federal reserved right.
State Appropriative Rights
Those water rights not reserved for federal use are delegated to the states. Each state has different laws regarding how people can use the state’s water. All western states have enacted laws that require water users to obtain a permit from the state. In general, those laws provide the highest priority to the earliest water users. This is known as the “Doctrine of Prior Appropriation” and is sometimes called “first in time, first in right.” However, even in the west, the laws vary from state to state. For information regarding the water rights and laws in your state contact the state or local agency responsible for water resources – see links to western state’s water resources web sites.
Administration of State Water Rights
The Federal Land Policy and Management Act of 1976 (FLPMA) states that periodically and systematically inventorying the public lands and their resources (including water) is in the public interest. The information gained from regular inventory and monitoring provides BLM with important input for public land management decisions regarding water and other resources. Detailed water resource data are available in the following national databases:
National Hydrography Dataset (NHD) is a detailed, comprehensive geospatial set of data about the Nation's surface water. The NHD also links to information housed in other databases. It contains features such as lakes, ponds, streams, rivers, canals, dams and stream gages. These data are designed to be used in general mapping and in the analysis of surface-water systems.
National Wetlands Inventory provides geospatial wetland data and maps to aid in wetland conservation efforts. The U.S. Fish and Wildlife Service (USFWS) is the principal Federal agency that provides information to the public on the extent and status of the Nation's wetlands.
National Water Information System (NWIS) provides public access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, and U.S. territories. NWIS is maintained by the U.S. Geological Survey (USGS), which investigates the occurrence, quantity, quality, distribution, and movement of surface and groundwater.
EPA STORET (short for STOrage and RETrieval) Data Warehouse is a repository for water quality, biological, and physical data and is used by state environmental agencies, EPA and other federal agencies, universities, private citizens, and many others.
Remote Automated Weather Stations (RAWS) of the Interagency Wildland Fire Management Program are strategically positioned throughout the U.S. The data collected from these stations includes wind speed and direction, wind gusts, precipitation, air temperature, solar radiation, relative humidity, fuel moisture, soil moisture and temperature.
National Climatic Data Center (NCDC) datasets are maintained by the National Oceanic and Atmospheric Administration (NOAA) and include the following:
Land-Based Observations contain various meteorological elements that over time describe the climate of a location or region. These elements include temperature, dew point, relative humidity, precipitation, snowfall, snow depth, wind speed, wind direction, cloudiness, visibility, atmospheric pressure, evaporation, soil temperatures, and various types of weather occurrences such as hail, fog, thunder, etc.
Upper Air Data (greater than 3 meters to 1000s of meters above the surface) consists of temperature, relative humidity, atmospheric pressure, and wind. Vertical profiles of atmospheric measurements (atmospheric soundings) are also available.
Surface Marine Observations contain various meteorological elements that over time can describe the nature of the climate of a location or region. These elements include temperature, dew point, relative humidity, precipitation, snowfall, snow depth on ground, wind speed, wind direction, cloudiness, visibility, atmospheric pressure, evaporation, soil temperatures, and various types of weather occurrences such as hail, fog, thunder, glaze, etc.
Weather/Climate Events Data provides summaries of weather and climate events. Such climate summaries are provided in a variety of formats, many based on a 'normal' base period of 30 years. Links to climate and weather information for such parameters as temperature, precipitation, hurricane events, and snow extremes are also available.
Paleoclimatology data come from natural sources such as tree rings, ice cores, corals, and ocean and lake sediments and provides data and information scientists need to understand natural climate variability and future climate change.