Abstract

Water use in Louisiana from 1960 to 2005 has complicated spatial and temporal trends that are not readily apparent in static tables. Web-accessible maps that illustrate quantity and category (e.g., irrigation, industrial, or public supply) of both surface water and ground water use by parish as well as charts that show use over time and distribution of use by type have been created using Google application programming interface (API). Ground water use varies from more than 200 million gallons per day in some rice-farming parishes to less than 40,000 gallons per day in coastal parishes where most ground water is not potable. East Baton Rouge Parish uses mostly ground water even though it is bounded on the west by the Mississippi River because the ground water is high quality and, prior to heavy industrial use, wells flowed to the surface. Orleans Parish which is just 70 miles down the river from East Baton Rouge Parish uses almost exclusively river water because most ground water is brackish. There was a rapid rise of water use for power generation from 1965 to 1980, especially along the Mississippi River. In 2005, power generation was 50% of the total water use in the state followed by industrial at 30%, rice farming at 7.6%, and public supply at 7%. Almost 85% of water use in 2005 was from surface sources. The economic downturn following the marked decline in oil price in the 1980s is clearly visible in industrial and farming water use. Some parishes, such as Vermilion, have made a dramatic switch from surface water to ground water due to decadal droughts or pollution of surface water. Web accessible data in an interactive, graphical format allows students, researchers, and policy makers to clearly see spatial or temporal trends as well as illustrate connections among water use and other factors.