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K. W. Toppin

Publications and source records attributed to K. W. Toppin.

11 recordsLinked to original sources
USGS1987

Hydrogeology of stratified-drift aquifers and water quality in the Nashua Regional Planning Commission Area, south-central New Hampshire

The Nashua Regional Planning Commission area in south-central New Hampshire is a 12-community area that is experiencing increases in population and in demands for water supply. The study area is underlain by 129 sq mi (40% of the area) of stratified drift which, where sufficiently saturated and permeable, form the most productive aquifers in the area. Eight towns use the stratified-drift aquifers for municipal water supply. The saturated thickness of stratified drift in the study area ranges from 0 or < 20 ft near aquifer boundaries to more than 100 ft in the Souhegan and Merrimack River valleys. The transmissivity of stratified drift ranges from < 2,000 sq ft/day throughout much of the area to more than 8,000 sq ft/day in the communities of Amherst, Brookline, Hollis, Hudson, Litchfield, Merrimack, Milford, Nashua, and Pelham. Directions of groundwater flow are generally from valley walls to surface waters, which act as drains for the stratified drift aquifers. The estimated total yield of community water-supply systems in the study area (surface and groundwater combined) is 22 mgd (million gallons per day). Analytical modeling indicates that an additional 12 mgd could be obtained from six aquifers located in the communities of Amherst, Litchfield, Merrimack, Milford, and Pelham. Other aquifers in the area, not modeled in the study, could also provide increased amounts of water especially where yields could be augmented by induced recharge of surface water. Groundwater quality in the study area is characterized by naturally elevated levels of iron (Fe) and manganese (Mn). Of 32 wells sampled, 7 exceeded EPA recommended drinking water limits for both Fe and Mn, and 3 wells exceeded the Mn limit only. The average total dissolved solids concentration for 32 samples was 121 mg/L. Groundwater in the area is slightly corrosive; pH 's ranged from 5.0-7.3. Groundwater contamination has been detected at two ' Superfund ' sites in the study area located in Milford and Nashua. At both sites, contamination of groundwater has caused the shutdown of municipal and private water supply wells. The widespread effect of applying highway deicing chemicals on groundwater quality is reflected by sodium (Na) concentrations that average 24 mg/L throughout the study area. At 11 of 32 sites sampled, EPA recommended limits for Na (20 mg/L) was exceeded.

New Hampshire↗
USGS1983

Appraisal of water-quality conditions, lower Black River, Windsor County, Vermont

Six hydroelectric power dams are planned along a 22-mile reach of the lower Black River in southeastern Windsor County, Vermont. Data were collected at 10 stations, during water years 1977-81, to appraise quality conditions before construction. Average specific conductance of Black River is 101 micromhos indicating low concentrations of dissolved solids. Concentrations of common constituents and minor elements were generally low and within safe levels for aquatic life. Near-saturated dissolved oxygen concentrations and relatively low mean total organic carbon concentrations indicate little oxygen-consuming substances in Black River. Mean total nitrogen concentrations ranged from 0.31 mg/L (milligrams per liter) to 0.61 mg/L. The highest concentrations were most likely due to secondary waste discharges entering the river. Nitrate was the primary form of inorganic nitrogen, mean concentrations ranged from 0.13 to 0.27 mg/L. Concentrations seem high enough to promote excessive algal growth in the proposed Hawks Mountain Reservoir. Mean concentrations of total phosphorus ranged from 0.014 to 0.112 mg/L as P. Maximum concentrations at all stations generally exceeded U.S. Environmental Protection Agency suggested levels for water entering lakes and reservoirs. Mean orthophosphorus concentrations ranged from 0.005 to 0.029 mg/L, suggesting a potential for nuisance algal conditions to develop in the proposed reservoir. Mean algal growth potential concentrations ranged from 1.3 to 8.8 mg/L, falling within the moderately high to high productivity range. No pesticides and polychlorinated biphenyls were detected. (USGS)

Water-Resources Investigations Report↗