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East Baton Rouge Parish: depth to the base of fresh groundwater, faults, and wells and gages discussed here. USGS.
Water use
In 2010, the parish withdrew about 171 million gallons a day (Mgal/d): about 150 from groundwater and 21.5 from surface water. Use peaked in 1970, at about 510 Mgal/d.
| Use | Groundwater | Surface water | Total |
|---|---|---|---|
| Industrial | 66.22 | 21.51 | 87.73 (51%) |
| Public supply | 75.12 | 0.00 | 75.12 (44%) |
| Power generation | 7.79 | 0.00 | 7.79 |
| Rural domestic | 0.28 | 0.00 | 0.28 |
| General irrigation | 0.25 | 0.00 | 0.25 |
| Livestock | 0.19 | 0.01 | 0.21 |
| Aquaculture | 0.04 | 0.00 | 0.04 |
| Total | 149.89 | 21.52 | 171.41 |
Water withdrawals, 1960–2010. USGS.
Groundwater
Fresh groundwater (chloride 250 mg/L or less) comes from three aquifer systems, shallowest to deepest: the Chicot, Evangeline and Jasper equivalents. (The Mississippi River alluvial aquifer along the west edge is a minor source.) Made of silt, sand and gravel between layers of clay, they are recharged by rain where they reach the surface to the north — in the Felicianas, St. Helena Parish and southwestern Mississippi — and dip and thicken southward, holding freshwater as deep as about 3,000 feet below sea level (NGVD 29).
| System | Main sands | 2010 withdrawals (Mgal/d) | Active wells (2014) | Well yields (gal/min) |
|---|---|---|---|---|
| Chicot | shallow, "400-foot," "600-foot" | 16.44 | 581, mostly domestic | 4–2,334 |
| Evangeline | "800-foot" to "1,700-foot" | 61.04 | 131, mostly public supply | about 20–3,000 |
| Jasper | "2,000-foot," "2,400-foot," "2,800-foot" | 72.33 | 126, mostly public supply | about 5–2,503 |
Falling levels (1991–2012):
- "600-foot" sand, well EB-827 (Chicot): down about 5 feet, with seasonal swings of about 10.
- "1,200-foot" sand, well EB-146 (Evangeline), in Baton Rouge: down about 35 feet.
- "2,800-foot" sand, well EB-1000 (Jasper): down about 20 feet.
Water levels in wells EB-827 (Chicot), EB-1000 (Jasper) and EB-146 (Evangeline). USGS.
Saltwater: the Baton Rouge Fault marks an abrupt change in how deep freshwater goes. North of it, freshwater reaches about 2,000 to 3,000 feet down in the Jasper. South of it, freshwater survives only in a small part of the "2,000-foot" sand and in the Chicot at shallower depths. Heavy pumping has drawn saltwater north across the fault into parts of the freshwater aquifers.
North–south hydrogeologic section through the parish; blue sands hold freshwater, tan sands saltwater. USGS, modified from Griffith (2003).
Quality: samples from 221 Chicot, 171 Evangeline and 151 Jasper wells show generally soft water that meets federal secondary standards for iron and dissolved solids; pH rises with depth.
Surface water
- Mississippi River: about 21.5 Mgal/d is withdrawn for industry. Levees mean it drains little of the parish, but it carries an average of about 460,000 cubic feet per second near Red River Landing (1928–76). Samples near St. Francisville (1978–2010) show hard water within secondary standards, with dissolved oxygen generally above 5 mg/L.
- Amite subbasin drains most of the parish: the Amite River near Denham Springs averaged 2,069 cubic feet per second (1913–2013) and the Comite River 479 (1944–2013). The Amite at Port Vincent had dissolved oxygen generally above 5 mg/L — the minimum for a diverse warm-water fish community — and a median pH of 6.8.
- Bayou Sara-Thompson subbasin, in the northwest corner, has few flow data.
Sources
Based on Vincent E. White and Lawrence B. Prakken, "Water Resources of East Baton Rouge Parish, Louisiana," U.S. Geological Survey fact sheet, prepared with the Louisiana Department of Transportation and Development; a work of the United States government in the public domain. The map, charts and tables are taken from the fact sheet's PDF.
Licença: CC0 1.0 (domínio público) · Adaptado de pubs.usgs.gov
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