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Richard Alfred Gardner

Publications and source records attributed to Richard Alfred Gardner.

6 recordsLinked to original sources
USGS1981

Model of the ground-water flow system of the Gordo and Eutaw aquifers in west-central Alabama

Hydrologic conditions for a two-aquifer system consisting of the Gordo and Eutaw aquifers of Cretaceous age in west-central Alabama were simulated using a three-dimensional finite difference digital model. The model was calibrated to observed heads in the aquifers using a least squares method for obtaining the values for hydraulic parameters which provided the best fit to 28 calibration points in the model. The standard error of estimate for computed heads in the model is 3.46 feet. Data collected during the period of 1900 to 1970 indicate that the modeled aquifer system is in a steady-state condition. The results of steady-state model simulations show that about 56 percent of the discharge from the system is by upward vertical leakage through confining beds to rivers, about 18 percent is to unregulated flowing wells, 10 percent is to pumped wells, and 16 percent is to boundaries. The areal distribution of water in the aquifer containing chloride concentrations greater than 1,000 mg/L appears to be related to flow patterns in the system. Areas of greatest head loss in the system are those where there is natural discharge and pumpage. More than 80 percent of the head loss in the system can be attributed to natural discharge by upward leakage through the confining beds.

Alabama↗
USGS1976

High-resolution seismic reflection profiling for mapping shallow aquifers in Lee County, Florida

High-resolution continuous seismic reflection profiling equipment was utilized to define the configuration of sedimentary layers underlying part of Lee County, Florida. About 45 miles (72 kilometers) of profile were made on the Caloosahatchee River Estuary and San Carlos Bay. Two different acoustic energy sources, a high resolution boomer and a 45-electrode high resolution sparker, both having a power input of 300 joules, were used to obtain both adequate penetration and good resolution. The seismic profiles show that much of the strata of middle Miocene to Holocene age apparently are extensively folded but not faulted. Initial interpretations indicate that: (1) the top of the Hawthorn Formation (which contains the upper Hawthorn aquifer) has much relief due chiefly to apparent folding; (2) the limestone, sandstone, and unconsolidated sand and phosphorite, which together compose the sandstone aquifer, appear to be discontinuous; (3) the green clay unit of the Tamiami Formation contains large scale angular beds dipping eastward; and (4) numerous deeply cut alluvium-filled paleochannels underlie the Caloosahatchee River. (Woodard-USGS)

Florida↗
USGS1976

Analog-model simulations for secondary canal controls and forward pumping water-management schemes in southeast Florida

The analog model of the Biscayne aquifer of southeast Florida was used to approximate the effects of two proposed water-management schemes. One involved adding a secondary control structure in a major canal which is controlled near the coast. In the model the controls were operated in accordance with canal water level both above and below the secondary control. Although the model could not differentiate between control openings of 1 foot or 5 feet, it showed that the secondary control is a viable method of conserving ground water. The second scheme involved pumping ground water ('forward pumping') from the Biscayne aquifer in inland areas during the dry season to: (1) augment canal flows toward the coast to sustain ground-water levels there, and (2) generate additional ground-water storage space for recharge in the wet season. Several sites on the model were programmed for forward pumping wells and the storage change was noted as a percentage of the ground-water withdrawal. (Woodard-USGS)

Florida↗
USGS1974

The 1971 drought in South Florida and its effect on the hydrologic system

The 1971 dry season rainfall in south Florida was low enough that the public media and concerned public officials unanimously characterized the event as a severe drought. Rainfall over all of south Florida during the 1970 wet season and the 1970-71 dry season was less than 85 percent of normal, as was the 1971 wet season on the heavily populated southeast coast of Florida. Rainfall during the dry season ranged from 20 to 63 percent of normal and recurrence intervals for dry season rainfall of this magnitude ranged from 100 years to several hundred years. Canal flow and ground-water levels reflected the drought conditions but in most cases did not set record lows. No permanent undesirable effects occurred as a result of the drought.

Florida↗