Public-Supply Groundwater Use by Aquifer Type within the Glaciated Conterminous United States, 2005-14

This dataset describes public-supply groundwater use by aquifer type within the glaciated conterminous United States between 2005 and 2014. All or part of 24 states within this glaciated region were included. The US Safe Drinking Water Act defines a "public water system" as an entity that provides water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days out of the year (United States Environmental Protection Agency, 1998). Water may be used for several purposes such as for commercial, industrial, and residential use, or may be used only for one specific purpose such as for residential use. 
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This dataset includes public-supply water systems that furnish their own groundwater supply, purchase groundwater from a neighboring water system, or are mixed water systems that use both ground- and surface water. Groundwater sources include wells, springs, and cross-connections to another public groundwater system. Systems that use exclusively surface water are excluded from this dataset. The surface-water sources and withdrawals of mixed water systems are excluded; however, some population served values might include persons served surface water.     
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Groundwater-use data that were collected from various agencies and resources spanned 2005-14, with a target year of 2010. Of the compiled withdrawal records, 95 percent were within the last five years, 2009-14, and 79 percent were from 2010. The year 2010 was chosen because it is the most recent year the USGS 5-year compilation report was published in United States Geological Survey (USGS) Circular 1405 (Maupin and others, 2014). 
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The goal was to differentiate groundwater withdrawals from unconsolidated sediments of the Quaternary Period, glacial sand and gravel deposits and stream-valley alluvium, from other non-Quaternary aquifers, mostly bedrock aquifers. There are five aquifer types defined in this study, which are Quaternary, Cretaceous (unconsolidated deposits of the Cretaceous Period), Bedrock, Mixed, and Unknown. 
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The water-use records include data from the United States Environmental Protection Agency (USEPA) and state agency databases. These records include 1) identifiers for the water system in the USEPA's Safe Drinking Water Information System (SDWIS) database, 2) type of public water supply system, 3) location, 4) population served by the system, 5) withdrawal rates, 6) well construction information, and 7) aquifer used. Most water systems and water sources were identified and located from the Safe Drinking Water Information System (SDWIS) (USEPA, 2013). Information on withdrawal rates, aquifer source, and well construction were compiled and cross-referenced from state and federal databases. Every water system and groundwater source had a withdrawal rate calculated or estimated. 90 percent (64,151 of 71,566 records) of the water system records had aquifer type assigned (either matched by associated records or estimated), and 41 percent (42,861 of 103,688 records) of the groundwater source records had well depth matched or inferred. 
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The glacial aquifer system is an important source of water supply for the United States. Around 2010, total population served by groundwater from public water systems within the glaciated region is 42.9 million persons, and around 2010, total public-supply withdrawal is around 5,367 cubic hectometers per year (hm3/yr) or 3,884 million gallons per day (Mgal/d). Exactly half of the total public-supply withdrawal was from Quaternary sediments, more if some part of the withdrawals from mixed and unknown aquifer types is included.

Tags: community-water-system, drinking-water, glacial-principle-aquifer-system, groundwater-withdrawal, non-community-water-system, population-served, public-supply, usgs-5a382bb2e4b0d05ee8b2133f, water-availability, water-supply, water-system, water-use
Organization: Department of the Interior