Water Resources of West Feliciana Parish, Louisiana

How much water West Feliciana Parish, Louisiana, has, how it is used and how good it is — from a U.S. Geological Survey fact sheet prepared with the Louisiana Department of Transportation and Development, drawing on earlier reports and the USGS National Water Information System.

How the water is used

In 2010 the parish withdrew about 41.7 million gallons a day (Mgal/d): about 37.0 Mgal/d (89 percent) of surface water and 4.68 Mgal/d of groundwater. Industry and power generation took about 89 percent (37.1 Mgal/d).

By source: the Mississippi River 36.69 Mgal/d and other streams 0.31; the Jasper equivalent aquifer system 4.17, the Chicot equivalent 0.45, the Mississippi River alluvial aquifer 0.04 and the Evangeline equivalent 0.02. Counted every five years, surface-water withdrawals for industry jumped from 0.00 Mgal/d in 1965 to 32.0 in 1970, and power-generation withdrawals from 0.00 to 24.5 Mgal/d between 1980 and 1985.

Groundwater

From shallowest to deepest the parish is underlain by the Mississippi River alluvial aquifer and the Chicot, Evangeline and Jasper equivalent aquifer systems — mostly beds of loose sand that thicken and dip south. Individual aquifers are generally at least 75 feet thick and can exceed 200 feet; the clay-and-silt confining units between them are generally at least 100 feet and up to 500 feet thick.

The base of fresh water — chloride of 250 milligrams per litre (mg/L) or less — lies about 300–600 feet below the National Geodetic Vertical Datum of 1929 (NGVD 29) in the far northwest (Turnbull Island) and about 2,000 feet below near the southern boundary; deeper aquifers generally hold salt water.

Rain is the main source of recharge, with leakage from aquifers above and, seasonally, from rivers. Water moves down-dip to the south and southwest at tens to hundreds of feet a year, and leaves by evapotranspiration, leakage to rivers and deeper aquifers, and wells. In 2009 state records listed 264 active wells — 153 domestic, 52 irrigation, 41 public supply, 16 industrial and 2 for power generation.

Mississippi River alluvial aquifer

Lies in the Mississippi flood plain in the west of the parish; its top is about 0 to 50 feet and its base about 100 to 150 feet below NGVD 29, essentially flat. A large fresh-water resource statewide, it had only 10 wells here in 2009 (5 irrigation, 3 rural domestic, 1 industrial, 1 public supply), 117 to 216 feet deep (median 137). Its water is generally very hard and above the EPA's secondary maximum contaminant levels (SMCLs) for iron and manganese.

Chicot equivalent aquifer system

The Upland terrace aquifer, present over most of the parish east of the alluvial aquifer, with its base from about 250 feet above to 250 feet below NGVD 29. Levels at well WF-188 near Bains showed no appreciable change from 1960 to 1990; well WF-158, northeast of St. Francisville, showed slight declines from 1998 to 2010.

• 64 active wells (49 rural domestic, 12 irrigation, 3 public supply), 14 to 200 feet deep, yielding 3 to 1,950 gallons per minute.
• Generally soft, low in dissolved solids; locally iron or salt water.

Evangeline equivalent aquifer system

The "800-foot," "1,000-foot," "1,200-foot," "1,500-foot" and "1,700-foot" sands of the Baton Rouge area, present everywhere except around Angola and Turnbull Island. In the north it lies between 200 feet above and 300 feet below NGVD 29 (about 500 feet thick); in the south between about 300 and 1,200 feet below (about 900 feet thick). Its fine-to-medium sands are 100 to 200 feet thick. Flow is mainly south; in 2003 levels in the 1,200- to 1,700-foot sands ranged from about 140 feet above NGVD 29 in the northeast to 40 feet below in the south. Well WF-254, in the "1,700-foot" sand near Bains, has declined about 10 feet since 1996.

• 128 active wells (75 domestic, 32 irrigation, 12 public supply, 9 industrial), 90 to 793 feet deep (median 259), yielding 3 to 400 gallons per minute.
• Generally soft, and generally within the SMCLs for pH, chloride, iron and dissolved solids.

Jasper equivalent aquifer system

The "2,000-foot," "2,400-foot" and "2,800-foot" sands of the Baton Rouge area, beneath the Evangeline. Its base lies from about 1,000 feet below NGVD 29 in the north to about 2,000 feet in the south; its sands are commonly 50 to 150 feet thick. In 2002 and 2006 levels ranged from about 40 feet above NGVD 29 in the north to about 20 feet below in the south, and water flows south toward the pumping centres of East Baton Rouge Parish. Well WF-222, in the "2,400-foot" sand at St. Francisville, has declined about 70 feet since 1960.

• 46 active wells (24 public supply, 14 domestic, 6 rural domestic, 2 power generation), 484 to 2,083 feet deep (median 852), yielding 6 to 1,900 gallons per minute.
• Generally soft, and generally within the SMCLs for colour, pH, iron, manganese and dissolved solids.

Surface water

About 37.0 Mgal/d of surface water was withdrawn in 2010, for industry, power generation, livestock and irrigation. All the industrial and power-plant water came from the Mississippi River, mostly for cooling, and was returned to it. Notable streams include Thompson Creek and Bayou Sara.

Below the Old River diversion, at Red River and Tarbert Landings (site 07373291) about 40 river miles upstream of St. Francisville, the Mississippi averaged about 460,000 cubic feet per second (about 298,000 Mgal/d) over 1928–76, according to U.S. Army Corps of Engineers records. Its water is generally hard and within the SMCLs for pH, chloride, sulfate and iron, with dissolved oxygen generally above 5 mg/L — the minimum for a varied community of warm-water life, sport fish included.

The fact sheet's figure caption assigns well WF-222 to the Evangeline and WF-254 to the Jasper equivalent system; its text and the graph's own labels place WF-222 in the Jasper ("2,400-foot" sand) and WF-254 in the Evangeline ("1,700-foot" sand), as here.

Sources

• Prakken, L.B., Lovelace, J.K., Tomaszewski, D.J., and Griffith, J.M., 2014, Water resources of West Feliciana Parish, Louisiana: U.S. Geological Survey Fact Sheet 2014–3039, prepared in cooperation with the Louisiana Department of Transportation and Development. https://pubs.usgs.gov/publication/fs20143039
• The tables and figures come from the fact sheet's PDF, which the web version lacks.
• Rewritten in hubnx's own words.