Lower Mississippi River Environmental Program. Report 2. A Physical Description of Main Stem Levee Borrow Pits along the Lower Mississippi River

摘要

Twenty-five borrow pits along the main stem levee system of the Lower Mississippi River were investigated with regard to selected physical, chemical, and biological resources as part of the Lower Mississippi River Environmental Program. Objectives of the levee borrow pit investigation are to develop an inventory of environmental resources of the borrow pits and to develop environmental design criteria for borrow pits to be used during levee construction. The 25 borrow pits were located between the levees along the Mississippi River from near New Madrid, Missouri (River Mile (RM) 877) to near Belmont, Louisiana (RM 151). Data on fishes, water quality, macrobenthos, and sediments were collected during the summer of 1981. A topographic field survey of each borrow pit was conducted during 1982. A vegetation survey was conducted from 1981 to 1983 as part of a companion study of bird and mammal use. Vegetation data are summarized in this report. Levee borrow pits range in size from one acre ponds to lakes of 50 or more acres. Traditional indicators of environmental quality based on morphological characteristics do not generally fit these unique aquatic basins. The borrow pit basins are generally shallow with most of the bottom in the photic zone. Physico-chemical indicators suggest a productive aquatic habitat. Although the data are survey in scope, it represents the first time a large number of borrow pits representing the entire Lower Mississippi River have been described and compared. (fr)