Geology topics

C.E. Simmons

Publications and source records attributed to C.E. Simmons.

4 recordsLinked to original sources

USGS1990

Effects of channel modifications on the hydrology of Chicod Creek basin, North Carolina, 1975-87

Drainage modifications in this Coastal Plain basin from 1978 to 1981 consisted of channel excavation and clearing of blockages. A study was begun in 1975 to define hydrologic conditions of the basin before, during, and after modifications and to determine what changes were attributed to modifications. Surface-water conditions were altered during and following modifications. Minimum flow at Juniper Branch was increased from less than 0.1 cu ft/sec to 0.4 cu ft/second;streamflow variability was reduced from an index of 0.87 to 0.49. In-channel velocity at Chicod Creek was increased from a mean of 0.4 ft/sec to 1.5 ft/sec. Substantial groundwater level declines were observed in wells 180 and 250 ft from Juniper Branch during the modifications phase;these were 0.4 and 0.2 ft, respectively. However, most surface-water and groundwater conditions returned nearly to premodification levels by 1987. Water-quality characteristics monitored during the investigation included physical, chemical, and bacteriological characteristics. Physical characteristics monitored were suspended sediment, temperature, dissolved oxygen, and pH. Of these physical characteristics, only sediment concentrations increased substantially during channel modifications. Chemical characteristics studied were major dissolved constituents, nutrients, trace metals, and pesticides. Substantial changes ranged from a decline in total iron concentrations of 77% to an increase in total nitrite concentrations of 130%. Changes in many chemical characteristics persisted following channel modifications. Bacterial counts did not change substantially.

North Carolina↗

USGS1984

Hydrologic conditions in the Chicod Creek basin, North Carolina, before and during channel modifications, 1975-81

Beginning in late 1978, stream channels throughout the 60-square mile Chicod Creek basin underwent extensive modification to increase drainage efficiency and reduce flooding potential. Drainage modifications in this Coastal Plain basin, consisting primarily of channel excavation and clearing of channel blockages, were completed in December 1981. The hydrologic condition of the basin before and during modification was determined from observed data. Observed data indicate hydrologic changes occurred in selected basin characteristics. For example, water levels in the surficial aquifer within 250 feet of Juniper Branch declined as much as 0.4 feet during modifications; at distances greater than 250 feet from the stream, ground-water levels did not change. Base flows increased, and suspended-sediment concentrations for high flows were several times greater than before channel modifications. Increases in selected chemical constituent concentrations in stream water during modifications were as follows: calcium, 12 percent; sodium, 18 percent; bicarbonate, 84 percent; and phosphorous, 80 percent. Significant changes were not found in either pesticide concentrations or coliform bacteria counts.

North Carolina↗

USGS1982

The effects of channel excavation on water-quality characteristics of the Black River and on ground-water levels near Dunn, North Carolina

During 1976-81 data were collected at three sites on the Black River near Dunn, N.C., to define the effects of channel excavation on stream quality and on ground-water levels in nearby areas. One of the data sites was located upstream from the five-mile long excavated reach and served as a background station. Changes in various characteristics of this Coastal Plain stream were determined by comparing data collected before, during, and after the construction period. After deepening of the channel by more than 2 feet, ground-water levels within 100 feet of the stream declined a proportionate amount; however, levels in a well 500 feet from the stream were unchanged. Flow velocities during channel deepening were 100 percent higher than velocities prior to construction. An average increase in water temperatures of about one degree Celsius was observed following removal of trees and brush that provided shading to the stream. After construction, concentrations of dissolved oxygen also increased. The percent of saturation increased 20 to 25 percent in the lower values. Maximum concentrations of suspended sediment increased from about 75 mg/L prior to construction to over 2000 mg/L during construction. Within a year after construction, levels of suspended sediment during stormflow had decreased but remained 5 to 10 times greater than preconstruction levels. Little or no change occurred in pH, total-dissolved solids, nitrogen, phosphorus, and bacteria.

North Carolina↗

USGS1977

Hydrology of the Creeping Swamp Watershed, North Carolina with reference to potential effects of stream channelization

Hydrologic data were collected for four years at six sites in the Creeping Swamp watershed in eastern North Carolina in a preliminary effort to study the effects of stream channelization on the hydrology of a small watershed. A water-budget evaluation for pre-channelized conditions showed that runoff accounts for about 17 percent of the total rainfall, base runoff about 20 percent, ground-water outflow about 2 percent, and evapotranspiration about 61 percent. Channelization would have caused the greatest decline in ground-water levels nearest the stream, with the decline diminishing with increased distance from the stream. Channelization would also have resulted in a decrease in overland runoff and an increase in the amount of water reaching Creeping Swamp through the ground-water system, although the total volume of runoff would not change significantly. The water-quality characteristics of Creeping Swamp indicate that the stream is relatively free of pollution, although it is likely that channelization would increase (1) suspended-sediment loads, (2) stream temperatures, and (3) concentrations of dissolved solids, especially during low flows.

North Carolina↗