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The Pearl River Basin (see figure) covers an area of about 7,800 square miles. The headwaters of the Pearl River consist of several tributaries in east-central Mississippi. From there the Pearl River flows southwesterly, forming the boundary between Louisiana and Mississippi in the southern part of the basin, and discharging into the Gulf of Mexico. The Pearl River is about 490 miles long and divides into the Pearl River and the West Pearl River about 50 miles above the mouth. Significant tributaries include the Yockanookany and Strong Rivers. Elevations in the Pearl River Basin range from sea level to almost 700 feet (0 to 210 meters) above sea level. Much of the upper two-thirds of the Pearl River Basin consists of gently rolling to hilly terrain. In the southern part of the basin, the land is much flatter. About 65 percent of the basin is forested, and about 30 percent is agricultural land. The timber industry and the manufacture of wood products dominate the economy of the lower basin, whereas soybeans and poultry are the major components of the economy in the upper basin.  The flow of the Pearl River near Monticello averages 54,600 gallons per second. However, in the past flow has been as low as about 2,000 gallons per second and as high as about 913,000 gallons per second. Use of surface water in the Pearl River basin is relatively large. About 1.2 million gallons per day are used for irrigation, about 6.2 million gallons per day are used for livestock, about 30.7 million gallons per day are used for industry, about 220,000 gallons per day are used for sand and gravel mining, and about 33 million gallons per day are used for municipal drinking-water supply. Turbidity is often high in the upper two-thirds of the Pearl River basin; however, the water quality of streams is generally fair. In the southern third of the basin, streams generally have a fast, deep flow and generally are of fair to good water quality. Water quality impacts occur below Jackson and at Columbia due to point and non-point sources of contamination. Channel diversions at the lower end of the Pearl River can leave the original river channel near Picayune virtually dry during low-flow conditions. Near the coast, the river becomes estuarine, bounded by salt marsh and affected by tidal influence. |