Geology Reports⌕ Search

Geology topics

G. H. Nelson

Publications and source records attributed to G. H. Nelson.

13 recordsLinked to original sources
USGS1986

Stage-discharge relations for Black Warrior River at Warrior Dam near Eutaw, Alabama; updated 1985

The construction of Warrior Dam, completed in 1962, has resulted in changes to the stage-discharge relations in the vicinity. The scarcity of current-meter measurements, coupled with backwater conditions, make definition of a single stage-discharge relation impossible without considerable error. However, as a useful alternative, limit curves were developed in 1983 that defined the limits of possible stage-discharge relations at the dam tailwater section. Since the 1983 report, 37 discharge values computed through the dam for the flood of December 1983 were used to verify or update the lower end of the limit curves. Data obtained from a current-meter measurement of the February 1961 flood (furnished by the U.S. Army Corps of Engineers) were used to update the upper end of the curves. This report presents the updated information. (USGS)

Open-File Report↗
USGS1985

Investigation of selected streamflow characteristics of the Alabama River upstream from Selma, Alabama

Available data for floods in the vicinity of Montgomery since the late 1800 's indicate that the flood of 1886 is the highest since settlement of the area in 1814. Profiles for floods in 1948, 1961, 1976, and 1979 were defined using floodmarks and recorded peak stages at gaging stations at Selma and Montgomery. The floods in 1948 and 1961 occurred before construction of Robert F. Henry Lock and Dam (formerly Jones Bluff Lock and Dam and Millers Ferry Lock and Dam). Considerable water-surface differences are indicated between the profiles for periods before and after construction of the dams. The investigation included a step-backwater model to reproduce profiles based on the actual flood profiles. After the actual flood profiles were reproduced, the model was used to compute additional profiles showing the effects of varying tributary inflow. The profiles were computed for discharges ranging from 80,000 ft3/s to 500 ,000 ft3/s. Stage-discharge relations were then developed for five sites upstream from Selma. Discharge coefficient curves for prevalent types of flow over the spillway at Robert F. Henry Lock and Dam were developed using discharges obtained from current-meter measurements and standard discharge equations for flow through gate-controlled spillways. (USGS)

Alabama↗
USGS1983

Preliminary stage-discharge relations for Tombigbee River at Aliceville lock and dam, near Pickensville, Alabama

The construction of Aliceville lock and dam and other related channel alterations, completed in 1979, has resulted in changes to the stage-discharge relations in the vicinity. The scarcity of current-meter measurements, coupled with backwater conditions, makes definition of a single stage-discharge relation impossible. However, limit curves can be defined that would encompass such a relation. Backwater is defined as water backed up or retarded in its course as compared with water flowing under normal or natural conditions. This results in a rise in stage above normal water level while the discharge remains unaffected. Backwater is usually caused by temporary obstruction(s) to flow downstream. Backwater at Aliceville Dam results from a variety of river conditions. Some of these conditions are large tributary inflow, return of flood plain flows to the main channel during recessions, and operations at Gainesville Dam during low flows. The discharges obtained from 26 current-meter measurements, along with computed discharges through the dam, are plotted versus stage. The plot illustrates, by the scatter of data points, the variations in backwater. Curves are drawn to envelope the extreme plot patterns showing possible ranges of several feet in stage for any given discharge. The upper end of the curves were extrapolated based on the results of a step-backwater analysis.

Alabama↗
USGS1983

Preliminary stage-discharge relations for Tombigbee River at Gainesville Dam, near Gainesville, Alabama

The construction of Gainesville Dam and other related channel alterations, completed in 1979, has resulted in changes to the stage-discharge relations in the vicinity. The lack of current-meter measurements, coupled with backwater conditions, makes definition of a single stage-discharge relation impossible. However, limit curves can be defined that would encompass such a relation. Backwater is defined as water backed up or retarded in its course as compared with water flowing under normal or natural conditions. This results in a rise in stage above normal water level while the discharge remains unaffected. Backwater is usually caused by temporary obstruction(s) to the flow downstream. Backwater at Gainesville Dam is due to large tributary inflow and return of flood plain flows to the main channel during recessions. The discharges obtained from 105 computations of flow through the dam for the tailwater and 59 for the pool were plotted versus stage. These plots illustrate, by the scatter of these data points, the variations in backwater. Curves were drawn to envelope the extreme plot patterns showing possible ranges of several feet in stage for any given discharge for both the pool and the tailwater.

Open-File Report↗
USGS1981

Flood of May 5 and 6, 1981, Mobile, Alabama

Heavy and intense rainfall in the late evening and early morning hours, May 5 and 6, 1981, caused widespread flooding along streams and low-lying areas in the port city of Mobile, Ala. More than 12 inches of rain fell between 6 p.m. May 5, and 3 a.m. May 6. Damage caused by flooding was estimated by the Mobile Department of Public Works to be millions of dollars. Maximum water surface elevations on streams in the area were 2 to 3 feet higher than those that occurred during a similar flood in April 1980. The approximate extent of flooding delineated on maps using flood profiles obtained by field surveys will provide a basis for formulating effective flood plain zoning that could minimize existing and future flood problems. (USGS)

Open-File Report↗