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D.C. Dickerman

Publications and source records attributed to D.C. Dickerman.

9 recordsLinked to original sources
USGS2003

Conjunctive-management models for sustained yield of stream-aquifer systems

Conjunctive-management models that couple numerical simulation with linear optimization were developed to evaluate trade-offs between groundwater withdrawals and streamflow depletions for alluvial-valley stream-aquifer systems representative of those of the northeastern United States. A conjunctive-management model developed for a hypothetical stream-aquifer system was used to assess the effect of interannual hydrologic variability on minimum monthly streamflow requirements. The conjunctive-management model was applied to the Hunt-Annaquatucket-Pettaquamscutt stream-aquifer system of central Rhode Island. Results show that it is possible to increase the amount of current withdrawal from the aquifer by as much as 50% by modifying current withdrawal schedules, modifying the number and configuration of wells in the supply-well network, or allowing increased streamflow depletion in the Annaquatucket and Pettaquamscutt rivers. Alternatively, it is possible to reduce current rates of streamflow depletion in the Hunt River by as much as 35% during the summer, but such reductions would result increases in groundwater withdrawals.

Journal of Water Resources Planning and Management↗
USGS1993

Hydrogeology, water quality, and ground-water-development alternatives in the upper Wood River ground-water reservoir, Rhode Island

The 72.4-square-mile Upper Wood River study area is in the Pawcatuck River basin in southern Rhode Island. Stratified drift is the only principal geologic unit capable of producing yields greater than 0.5 Mgal/d. Transmissivity of the aquifer ranges from 7,600 to 49,200 sq ft/d. Water-table conditions prevail and the aquifer is in good hydraulic connection with perennial streams and ponds. Groundwater and surface water in the study area are generally suitable for most uses. Water is soft, slightly acidic, and contains less than 150 mg/L dissolved solids. Locally, however, groundwater has been contaminated with nitrate, chloride, and volatile organic compounds. A model of the groundwater-flow system was used to evaluate the effect of alternative schemes of groundwater development on water levels, pond levels, and streamflow. Till contacts were simulated as specified-flux boundaries, drainage divides as no-flow boundaries, and streams as leaky boundaries. The areas most favorable for development of 1 Mgal/d are along the Flat and Wood Rivers. From 50 to 65 percent of the water withdrawn from wells would be derived from induced recharge. Results of simulation of development alternatives indicate that the groundwater reservoir could sustain withdrawals of 6 to 12 Mgal/d from 11 wells under long-term average annual (1942-89) and simulated drought (1963-66) conditions without causing water-level declines of greater than 25 percent of the unstressed saturated thickness of the aquifer. Pumping 12 Mgal/d, however, would reduce flow of the Wood River at the basin outlet by an amount almost equal to the 7-day, 10-yr low flow of 20.4 cu ft/s.

Water-Resources Investigations Report↗
USGS1985

Hydrology, water quality, and ground-water-development alternatives in the Chipuxet ground-water reservoir, Rhode Island

A glacial sand and gravel aquifer in the Chipuxet River basin of Rhode Island forms a ground-water reservoir that could yield as much as 8.6 million gallons per day to wells; however, some streams would go dry for extended periods of time. The State Water Resources Board has tested five site that it proposes to develop for a public supply of 3 million gallons per day. A digital model was used to determine how withdrawal at this rate from alternative combinations of wells would affect water levels and streamflow. Results show that withdrawal of 3 million gallons per day would have a minimal effect on water levels, but that withdrawal at this rate from some well combinations could cause the Chipuxet River to have little or no flow for 90 consecutive days on the average of 1 year in 20. Quality of ground water is generally good, but leaching of fertilizers applied to croplands, which overlie much of the aquifer, has caused locally excessive concentrations of nitrate. Induced infiltration of surface water through organic sediments that line the bottoms of ponds and streams also seems to be the cause of elevated concentrations of manganese in water from some heavily pumped wells. (USGS)

Water-Resources Investigations Report↗
USGS1985

Hydrogeology, water quality, and ground-water development alternatives in the Beaver-Pasquiset ground-water reservoir, Rhode Island

In a 23 sq mi study area, the Beaver-Pasquiset groundwater reservoir within the Pawcatuck River basin in southern Rhode Island, stratified drift is the only principal geologic unit capable of producing yields > 350 gal/min. Transmissivity of the aquifer ranges from 7,200 to 24,300 sq ft/day. Water table conditions prevail in the aquifer, which is in good hydraulic connection with perennial streams and ponds. A digital model of two-dimensional groundwater flow was used to simulate the interaction between surface water and groundwater, and to evaluate the impact of alternative schemes of groundwater development on groundwater levels, pond levels, and streamflow in the Beaver-Pasquiset groundwater reservoir. Transient simulations of theoretical pumpage were made for a drought period (1963-66) and a wet period (1976-78). The areas most favorable for development of high-capacity wells (350 gal/min or more) are along the Beaver River and near Pasquiset Pond. The water is soft and generally contains < 100 mg/L dissolved solids. Locally, groundwater contains elevated concentrations of iron and manganese (7.5 and 3.7 mg/L, respectively), southeast of Pasquiset Pond, and will require treatment if used for public supply. The groundwater reservoir was simulated with a two-dimensional finite-difference model using a block-centered grid consisting of 33 rows and 75 columns. Differences between measured and simulated water table altitudes for the final steady state run for 21 selected observation wells averaged +0.07 ft. Combined pumping rates for simulation of groundwater development alternatives at eight sites ranged from 3.25 to 7.00 Mgal/d. Pumping rates for individual wells ranged from 0.25 to 1.50 Mgal/d. Transient simulations suggest that the Beaver-Pasquiset groundwater reservoir is capable of sustaining a pumping rate of 4.25 Mgal/d during years of average groundwater recharge with minimal impact on groundwater levels, pond levels, and streamflow. During extreme drought periods (1965 and 1966) it would be necessary to reduce pumpage below 3.25 Mgal/d to maintain flow in both the Beaver River and Pasquiset Brook. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1984

A modification of the finite-difference model for simulation of two dimensional ground-water flow to include surface-ground water relationships

The two-dimensional finite-difference model for simulation of groundwater flow was modified to enable simulation of surface-water/groundwater interactions during periods of low streamflow. Changes were made to the program code in order to calculate surface-water heads for, and flow either to or from, contiguous surface-water bodies; and to allow for more convenient data input. Methods of data input and output were modified and entries (RSORT and HDRIVER) were added to the COEF and CHECKI subroutines to calculate surface-water heads. A new subroutine CALC was added to the program which initiates surface-water calculations. If CALC is not specified as a simulation option, the program runs the original version. The subroutines which solve the ground-water flow equations were not changed. Recharge, evapotranspiration, surface-water inflow, number of wells, pumping rate, and pumping duration can be varied for any time period. The Manning formula was used to relate stream depth and discharge in surface-water streams. Interactions between surface water and ground water are represented by the leakage term in the ground-water flow and surface-water mass balance equations. Documentation includes a flow chart, data deck instructions, input data, output summary, and program listing. Numerical results from the modified program are in good agreement with published analytical results. (USGS)

Water-Resources Investigations Report↗
USGS1974

Availability of ground water in the Branch River basin; Providence County, Rhode Island

Stratified glacial drift consisting largely of sand and gravel constitutes the only aquifer capable of supporting continuous yields of 100 gpm (6.3 1/s) or more to individual wells. The aquifer covers about a third of the 79 mi 2 (205 km2) study area, occurring mainly in stream valleys that are less than a mi le wide. Its saturated thickness is commonly 40 to 60ft (12 to 18 m); its transmissivity is commonly 5,000 to 8,000 ft 2/day (460 to 740m2 /day). The aquifer is hydraulically connected to streams that cross it and much of the water from heavily pumped wells will consist of infiltration induced from them. Potential sustained yield from most parts of the aquifer is limited chiefly by the rate at which infiltration can be induced from streams or low streamflow, whichever is smaller. Ground-water withdrawals deplete streamflow; and if large-scale development of ground water is not carefully planned and managed, periods of no streamflow may result during dry weather. Potential sustained yield varies with the scheme of well development, and is evaluated for selected areas by mathematically simulating pumping from assumed schemes of well Is in models of the stream-aquifer system. Results indicate that sustained yields of 5.5, 3.4, 1.6, and 1.3 mgd (0.24, 0.15, 0.07, and 0.06 m3 /s) can be obtained from the stratified-drift aquifer near Slatersville, Oakland, Harrisville, and Chepachet, respectively. Pumping at these rates will not cause streams to go dry, if the water is returned to streams near points of withdrawal. A larger ground-water yield can be obtained, if periods of no streamflow along reaches of principal streams are acceptable. Inorganic chemical quality of water in the stream-aquifer system is suitable for most purposes; the water is soft, slightly acidic, and generally contains less than 100 milligrams per litre of dissolved sol ids. Continued good quality ground water depends on maintenance of good quality of water in streams, because much of the water pumped from wells will be infiltrated from streams.

Rhode Island↗