¿Ves algo que mejorar? Propón un cambio.
Knowing how much water Red River Parish, in northwest Louisiana, has, how it is used and how good it is helps water managers and residents look after it. This U.S. Geological Survey fact sheet, prepared with the Louisiana Department of Transportation and Development, sums it up.
How the water is used
In 2014 the parish withdrew about 5.76 million gallons a day (Mgal/d): 4.23 from groundwater and 1.54 from surface water.
| Use (2014) | Groundwater | Surface water | Total (Mgal/d) |
|---|---|---|---|
| General irrigation | 2.57 | 0.64 | 3.21 |
| Rice irrigation | 0.74 | 0.08 | 0.83 |
| Livestock | 0.04 | 0.06 | 0.11 |
| Public supply | 0.65 | 0.37 | 1.03 — about 18% |
| Industry | 0.01 | 0.37 | 0.39 — about 7% |
| Rural domestic | 0.20 | 0.00 | 0.20 — about 4% |
Agriculture — general irrigation, rice irrigation and livestock — took about 72 percent (4.15 Mgal/d). Figures are rounded, so they may not add up exactly.
Water withdrawals, 1960–2014, measured every five years to 2010 and again in 2014. They peaked in 1975 at more than 7.3 Mgal/d.
| Source (2014) | Mgal/d |
|---|---|
| Red River alluvial aquifer | 2.88 |
| Carrizo-Wilcox aquifer | 0.95 |
| Upland terrace aquifer | 0.35 |
| Other aquifers | 0.04 |
| John K. Kelly Grand Bayou Reservoir | 0.37 |
| Red River | 0.30 |
| Bayou Pierre | 0.16 |
| Other surface water | 0.70 |
The aquifers
Red River Parish. Shading shows the approximate altitude of the base of fresh groundwater; A–A′ is the section below. From the USGS fact sheet.
The main freshwater aquifers are the Red River alluvial, the Carrizo-Wilcox and the Upland terrace. The Dolet Hills and Naborton aquifers, below the Carrizo-Wilcox, exist only as thin lenses in their confining units, have few registered wells and provide little fresh water. Fresh groundwater — 250 milligrams per litre (mg/L) of chloride or less — reaches from more than 50 feet above sea level (NGVD 29) along the middle of the parish, in the alluvial aquifer, to deeper than 100 feet below it in the northeast, in the Carrizo-Wilcox.
An idealised west-to-east section through the parish; individual sand and clay layers are not shown.
Red River alluvial aquifer
- Extent: a narrow band in the western half of the parish — the most heavily pumped aquifer there. Sediments laid down mainly by the Red River grade from silt and clay at the surface to coarse sand and gravel at the base.
- Thickness: about 80 feet along the western border and about 40 feet in the east; the base sits at a fairly constant 50 feet above NGVD 29.
- Recharge: mainly rain, plus leakage from aquifers below.
- Water levels: steady at wells RR-210 and RR-218, with seasonal swings of 5 to 10 feet following rainfall and the level of the Red River, and little or no long-term trend. RR-210 rose sharply around 1995, probably because the Russell B. Long Lock and Dam (Lock and Dam No. 4) was completed on the Red River in the south of the parish in 1994.
- Wells (2017): 99 active — 45 irrigation, 40 domestic, 6 public supply, 8 industrial.
- Use (2014): 2.29 Mgal/d general irrigation, 0.53 rice irrigation, 0.03 livestock, 0.02 rural domestic.
Carrizo-Wilcox aquifer
The Carrizo Sand and the Wilcox aquifer, sands and gravels of Paleocene and Eocene age, are connected and treated as one aquifer. It lies under the whole parish, thickening from west to east. Water under the Red River is mostly salty; fresh water is generally found east of the river.
- Fresh water: shallow over much of the parish, usually less than 10 feet deep, staying near NGVD 29 in the west; between the middle and the east of the parish its base drops sharply, from about 50 to about 200 feet below NGVD 29. Groundwater moves toward the Red River.
- Water levels: in 2013, between 110 and about 170 feet above NGVD 29 from the middle of the parish to the northeast corner. Well RR-278 (1981–2016) usually varied less than a foot a year, rising about 3 feet from 1981 to 2000 and then falling about 5 feet.
- Wells (2017): 207 active — 151 domestic, 25 public supply, 16 irrigation, 15 industrial; 20 to 500 feet deep; yields 5 to 500 gallons a minute.
- Use (2014): about 0.60 Mgal/d public supply, 0.16 rice irrigation, 0.10 general irrigation, 0.09 rural domestic.
Upland terrace aquifer
A nearly continuous, slender ring around the east, south and west of the Carrizo-Wilcox's extent in the parish. Its deposits coarsen with depth, from clay and silt at the top to gravel at the bottom; it is recharged mainly by rain, and also by leakage from below.
- Water levels: RR-261 barely changed from 1978 to about 1990, then rose about 10 feet from 1990 to 2000. RR-276 held at about 210 feet in 1980–88 and again in 2000–17.
- Wells (2017): 122 active — 109 domestic, 5 public supply, 4 irrigation, 4 industrial; 18 to 100 feet deep; yields 2 to 165 gallons a minute.
- Use (2014): 0.18 Mgal/d general irrigation, 0.08 rural domestic, 0.05 rice irrigation, 0.02 public supply, 0.01 industry, under 0.01 livestock.
Water levels in wells RR-210 and RR-218 (Red River alluvial), RR-261 and RR-276 (Upland terrace) and RR-278 (Carrizo-Wilcox).
Groundwater quality
The state's long-term monitoring sampled 60 Carrizo-Wilcox wells (1955–2014), 59 alluvial wells (1954–2013) and 14 Upland terrace wells (1941–78). Results were generally within the EPA's secondary maximum contaminant levels (SMCLs) — guidelines for taste, colour, staining and similar effects — for colour, chloride and sulfate.
| Red River alluvial | Carrizo-Wilcox | Upland terrace | SMCL | |
|---|---|---|---|---|
| Median hardness | 480 mg/L — very hard | 33.2 mg/L — soft | 22 mg/L — soft | — |
| Median pH | 7.0 | 7.3 | 6.4 | 6.5–8.5 |
| Samples within the pH range | 98% | 86% | 36% | |
| Median iron | 4,000 µg/L | 250 µg/L | 160 µg/L | 300 µg/L |
| Samples above the iron limit | 95% | 47% | 25% | |
| Median manganese | 400 µg/L | 30.6 µg/L | 35 µg/L | 50 µg/L |
| Samples above the manganese limit | more than 99% | about 30% | about 30% |
Surface water
Four subbasins drain the parish. In 2014, 1.54 Mgal/d of surface water was used for general irrigation (0.64), industry (0.37), public supply (0.37), rice irrigation (0.08) and livestock (0.06).
| Subbasin | Where, and main streams | Streamflow record |
|---|---|---|
| Black Lake Bayou (HUC 11140209) | most of eastern Red River Parish; Grand Bayou, Black Lake Bayou, Brushy Creek | Grand Bayou near Coushatta, 1957–96: average 104 ft³/s; monthly averages from 222 in February to 7.5 in October |
| Bayou Pierre (HUC 11140206) | the whole western border, to the western edge of the Red River; Bayou Pierre, which forms the border, and the Prairie River | Bayou Pierre near Lake End (Natchitoches Parish), 1981–2018: average 971 ft³/s; from 2,043 in February to 220 in August |
| Middle Red–Coushatta (HUC 11140202) | the west-centre, along the Red River; the Red River, Coushatta Bayou | Red River at Coushatta, 1939–52: average 31,159 ft³/s; from 62,113 in May to 9,943 in September |
| Loggy Bayou (HUC 11140203) | the north-centre, east of the Red River; Loggy Bayou | Loggy Bayou near East Point, 1981–86: average 1,968 ft³/s; from 4,466 in February to 270 in August |
Surface-water quality
Samples from the Red River at Coushatta (1969–2010) and Grand Bayou near Coushatta (1955–86) were generally within the SMCLs for chloride and sulfate.
| Red River at Coushatta | Grand Bayou near Coushatta | |
|---|---|---|
| Median hardness | 124 mg/L — hard | 29 mg/L — soft |
| Median dissolved oxygen | 8.5 mg/L | 6.7 mg/L |
| Median pH | 7.7 — within the range | 6.3 — outside it in 56% of samples |
| Median iron / manganese | 23 / 4 µg/L — within limits | 495 / 2,150 µg/L — iron above its limit in 83% of samples, manganese in all |
| Median colour | 40 PCU | 70 PCU |
Both sites' median colour was above the SMCL of 15 platinum-cobalt units. Five mg/L of dissolved oxygen is considered the minimum for a diverse community of freshwater warm-water life, including sport fish.
Sources
- Robinson, A.L., and White, V.E., 2020, Water resources of Red River Parish, Louisiana: U.S. Geological Survey Fact Sheet 2020–3053, prepared in cooperation with the Louisiana Department of Transportation and Development. https://pubs.usgs.gov/publication/fs20203053
- The tables, figures and captions come from the fact sheet's PDF, which the web version lacks.
- For the alluvial aquifer's wells the fact sheet runs depths and yields together ("depths … ranged from 17 to 150 gallons per minute"), so neither is given here. It says Grand Bayou's pH was "greater than" the SMCL range; its median of 6.3 is below it, so this page says "outside".
- Rewritten in hubnx's own words.
Licencia: CC0 1.0 (dominio público) · Adaptado de pubs.usgs.gov
1
0
0
0
Comentarios
