Availability and compilation of selected streamflow data for the Mobile River and its distributaries including the lower Alabama River and the lower Tombigbee River

Abstract

The U.S. Army Corps of Engineers and the U.S. Geological Survey have collected streamflow data in and near the Mobile Estuary, in southwestern Alabama since 1940. These data include stage, stream velocity, and waterquality information, which were collected from 12 gaging stations and at miscellaneous sites in the area. From 1978 to 1983 over 100 discharge measurements were made along the U.S. Highway 90 Causeway, for the Tensaw, Apalachee, and Blakeley Rivers. Flood profiles for the Mobile River study area have been compiled and are on file with the U.S. Army Corps of Engineers, Mobile District. This report summarizes and categorizes the data collected in southwestern Alabama and lists the availability of the data and the location where the data are on file. INTRODUCTION The Mobile River, together with its lakes, shallow swamps, tributaries, and distributaries, is an abundant water resource in Mobile and Baldwin Counties in southwestern Alabama. The uses of this water resource are varied. Industry uses the Mobile River as a water highway to transport goods, utilities use the water supply for power plants, recreational uses are enjoyed by many, and this water system serves as an environmental habitat for a variety of fish and wildlife. Some or all of these uses, as well as the river system itself, may be affected by man-made and natural changes. Questions, including how the construction of a bridge may affect the flow of a river, how much damage may be done to the ecology of the area, and how the quality of the water would change if a hurricane should strike, may be answered through the use of streamflow models. However, effective use of these models requires adequate streamflow data. Streamflow data have been collected in the area since 1940, and some of these data are published in various reports. Gaging stations have been established to collect continuous stage data and discharge, velocity, specific conductance, and water temperature measurements have also been made. These data will be helpful in future studies. Compilation of these data will provide a much needed source for future studies. Purpose and Scope The purpose of this report is to describe the type of streamflow data that have been collected along the Mobile River and its distributaries, list its availability and identify where it may be obtained. Data collected for the lower reaches of the Alabama and Tombigbee Rivers are also included. For this report, the lower reaches of the Alabama and Tombigbee Rivers are defined as south of Dead River on the Alabama River and south of Bates Lake on the Tombigbee River. The technical scope of the report includes the identification and compilation of available discharge, water temperature, and velocity data collected in the study area. Stream gaging stations were established in 1978 to record water quality and velocity data along the U.S. Highway 90 Causeway for the Apalachee, Blakeley, and Tensaw Rivers, and other gaging stations were established in other locations in the study area to record stage data. Acknowledgments Appreciation is expressed to the U.S. Army Corps of Engineers, Mobile District, for their cooperation and assistance. STUDY AREA The study area includes the lower reaches of the Alabama and Tombigbee Rivers, and the Mobile Estuary which includes the Apalachee, Blakeley, Mobile, and Tensaw Rivers above U.S. Highway 90. For this report, the lower reaches of the Alabama and Tombigbee Rivers are defined as south of Dead River on the Alabama River and south of Bates Lake on the Tombigbee River (fig. 1). Description of Area The lower reaches of the Alabama and Tombigbee Rivers flow through a primarily flat and wooded terrain. The confluence of these rivers, approximately 30 miles north of the city of Mobile, forms the Mobile River which flows in a single channel for about five miles before entering the Mobile Estuary which consists of a maze of small channels, lakes, and bayous. As it enters this swampy estuary, the Mobile River diverges into two distinct channels; the Mobile River which flows along the western section of the estuary, and the Tensaw River which flows along the eastern section of the estuary. The Mobile River discharges into Mobile Bay at the city of Mobile. The area of the Mobile River and its estuary is 520 mi 2 of which approximately 85 percent is marshland. The Tensaw River divides into several channels enroute to Mobile Bay, and discharges into the bay through the Apalachee, Blakeley, and Tensaw Rivers.