Influences of land use on water quality of a diverse New England watershed.
Analysis of variations in major ion chemistry in the Mill River watershed reveals the importance of anthropogenic activities in controlling streamwater chemistry. Average concentrations of NO3- and SO4(2-) show a positive correlation with percent catchment area altered by human land uses, and concentrations of Cl- increase with road density. Water removal from municipal reservoirs increases the downstream concentration of NO3- and SO4(2-) over that predicted by land use changes, showing that removal of high quality upstream water concentrates pollutants downstream. In salt-impacted streams, Cl- exceeds Na- by 10-15% due to cation exchange reactions that bind Na+ to soil. The net effect of nonpoint source pollution is to elevate ANC in the most developed areas, which impacts the natural acidity of a large swamp. The sum of base cations (C(B)) exceeds ANC for all samples. Plotting C(B) against ANC and subtracting Cl- quantifies the impact of road salt from the impact of the addition of strong acids.
Rhodes
A L
AL
Department of Geology, Smith College, Northampton, Massachusetts 01063, USA. arhodes@science.smith.edu
Newton
R M
RM
Pufall
A
A
D004784:Environmental Monitoring; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000032:analysis; D018986:Motor Vehicles; D009511:New England; D014867:Water / Q000737:chemistry; D014873:Water Pollutants / Q000032:analysis*
D007477:Ions; D014873:Water Pollutants; D014867:Water