Water Resources of East Feliciana Parish, Louisiana

Knowing how much water East Feliciana Parish, Louisiana, has, how it is used and how good it is matters for managing it. This U.S. Geological Survey fact sheet, prepared with the Louisiana Department of Transportation and Development, draws on earlier reports and the USGS National Water Information System to give water managers, residents and others that picture.

How much water is used

In 2010 the parish withdrew about 3.76 million gallons a day (Mgal/d): 3.51 from groundwater and 0.25 from surface water. Public supply took about 80 percent (3.00 Mgal/d); the rest went to industry, rural homes, livestock and general irrigation. Records kept every five years since 1960 show withdrawals peaking in 1960, at about 4.29 Mgal/d. Groundwater withdrawals have generally risen since 1975, largely because public supply grew from 0.20 Mgal/d in 1960 to 3.00 Mgal/d in 2010.

Groundwater and surface-water withdrawals in East Feliciana Parish, 1960–2010. USGS.

Groundwater

The parish's fresh groundwater — no more than 250 milligrams per litre (mg/L) of chloride — comes from, shallowest to deepest, the Chicot, Evangeline and Jasper equivalent aquifer systems and the Catahoula aquifer; deeper aquifers hold saltwater. The base of fresh water is shallowest on the western border, less than 1,500 feet below the National Geodetic Vertical Datum of 1929 (NGVD 29), and deepest in the east, reaching 2,300 feet in the northeast corner.

The aquifers are recharged mainly by rain falling in the parish and as far as about 100 miles north into Mississippi, and a little by streams. They lose water by leaking into neighbouring aquifers, flowing into streams, and through wells. They generally dip south to southwest, and are mostly sand, separated by clay layers except where those are missing and the sands merge.

East Feliciana Parish: depth to the base of fresh groundwater, subbasins, and the wells and river sites described here. USGS.

More on each aquifer

• Upland terrace. It reaches the surface along ridges and valley sides and dips south to southwest at 10–30 feet per mile, merging with the "400-foot" and "600-foot" sands of the Baton Rouge area near the southern parish line. Being near the surface, it takes in rain and passes it down to deeper aquifers. Its base is more than 200 feet above NGVD 29 in the north and 100–200 feet below in the south. In 2009 water levels ranged from about NGVD 29 near the Mississippi River in the far southwest to more than 230 feet above northeast of Clinton; groundwater flows mostly south, following the land surface, and locally toward stream valleys.
• Evangeline. Its base lies from more than 300 feet below NGVD 29 near the northern line to about 800–1,300 feet near the southern line. In 2003, levels in the "1,500-foot" and "1,700-foot" sands ranged from about 165 feet above NGVD 29 in the northeast to about 45 feet below in the far southwest, with water flowing southwest toward pumping centres in East Baton Rouge Parish. At well EF-61 in Clinton, the "1,200-foot" sand fell about 8 feet from 1995 to 2008, changed little until 2013, then rose about 5 feet by 2015.
• Jasper. Its base is not well defined, probably from more than 1,500 feet below NGVD 29 in the north to about 1,900–2,300 feet in the south. In 2006, water in the "2,800-foot" sand flowed southwest toward a pumping centre in northwestern East Baton Rouge Parish, with levels from about 60 feet above NGVD 29 in the far northeast to about 40 feet below in the far southwest. At well EF-185 it fell about 10 feet between 1996 and 2005, then changed little until 2015.
• Catahoula. Its extent and thickness are not well known. Near Norwood it lies about 1,500–2,100 feet below NGVD 29, and its main sand layers can exceed 450 feet in thickness, with saltwater in the lowest.

Groundwater quality

Samples from 26 Chicot, 29 Evangeline and 27 Jasper wells had median values that were soft and within the Environmental Protection Agency's secondary (non-enforceable) limits for colour, iron, manganese and dissolved solids. Median pH ranged from 5.7 to 8.3 and median temperature from 20.0 to 28.2 °C (68.0 to 82.8 °F), both generally rising with depth. Locally, iron can far exceed its limit in the Evangeline and Jasper systems, and manganese in the Jasper. Limited data show Catahoula water to be soft and alkaline and within the limits for iron, manganese and dissolved solids.

Surface water

About three-quarters of the parish, in the east, lies in the Amite River subbasin and most of the western quarter in the Bayou Sara–Thompson subbasin, both part of the Lake Maurepas basin; only the far southwestern tip drains to the Lower Mississippi–Baton Rouge basin. In 2010, 0.25 Mgal/d was drawn from miscellaneous streams, for livestock and general irrigation.

• The Amite River forms in the northeast corner where the West and East Forks, both rising in Mississippi, meet, and flows south along the eastern boundary. Near Darlington it averaged about 906 cubic feet per second in 1951–2014, from 580 square miles.
• The Comite River drains the centre of the parish, fed by Comite Creek, Pretty Creek and smaller streams; near Olive Branch it averaged 231 cubic feet per second in 1943–2014, from 145 square miles. Beaver Creek, Horton Bayou, Sandy Creek and Redwood Creek also lie in the Amite subbasin.
• Thompson Creek drains the narrow Bayou Sara–Thompson subbasin along the western border and flows into the Mississippi River.
• The Mississippi River receives drainage from more than 40 percent of the conterminous United States; near Red River Landing it averaged about 460,000 cubic feet per second in 1928–76.

Surface-water quality

Samples from the Mississippi River near St. Francisville (1978–2010) and the Amite River near Darlington (1961–1976) had median pH, chloride, sulfate and iron within the secondary limits, and Mississippi River dissolved oxygen was generally above 5 mg/L, considered the minimum for a diverse community of warm-water life, including sport fish. Mississippi water quality varies with the season, rainfall and land use: farm pesticides and nutrients are generally highest in June and July, the "spring flush" of runoff from upstream fields.

Sources

• U.S. Geological Survey, in cooperation with the Louisiana Department of Transportation and Development, Water Resources of East Feliciana Parish, Louisiana, Fact Sheet 2016–3069, January 2017. https://doi.org/10.3133/fs20163069
• USGS Lower Mississippi-Gulf Water Science Center: http://la.water.usgs.gov