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

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Authors:Dickerman, David C.; Ozbilgin, Melih M.
Author Affiliations:Primary:
U. S. Geol. Surv., Providence, RI, United States
Univ. R.I., United States
Source:Reston, VA [Water-Resources Investigations - U. S. Geological Survey, No.WRI85-4190, 104p. Publisher: U. S. Geological Survey,], United States. ISSN: 0092-332X
Publication Date:1985
Note:In English. 46 refs. Hydrogeol. maps
Summary: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)
Subjects:Aquifers; Clastic sediments; Data processing; Digital simulation; Drainage basins; Drift; Finite difference analysis; Ground water; Hydrogeologic maps; Hydrogeology; Hydrographs; Layered materials; Maps; Mathematical models; Sediments; Statistical analysis; Surveys; USGS; Water quality; Water resources; Water supply; Beaver River; Kent County Rhode Island; Providence County Rhode Island; Rhode Island; United States; Washington County Rhode Island; Pasquiset Brook; Pawcatuck River basin; Southern Rhode Island
Coordinates:N412500 N413800 W0713500 W0714500
Record ID:1986029171
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from USGS product, Selected Water Resources Abstracts, Reston, VA, United States
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