Assessing land-use/ water-quality relationships across contrasting geologic areas in New Jersey

摘要

all, 13 stream water-qualityparameters, including specific conductance (SC), pH,dissolved oxygen (DO), dissolved organic carbon (DOC), three nutrients, and six majorions were compared between the northern bedrock and southern coastal plain regionsof New Jersey, USA and related to watershed-disturbancegradients characterizedby the percentage of urban land, impervious surface (IS), agriculture, and alteredland (sum of urban land and agriculture) in the watersheds. SC, DO, calcium, magnesium,sodium, and chloride concentrations were greater in the north. DOC was higherand pH was lower in the south. Nutrient, potassium, and sulfate concentrations didnot differ between regions. Regional water-qualitydifferences are attributed to geologicsetting and land use. Except for DO in southern streams, all water-qualityparameterswere related to urban land, agriculture, or both. Significant correlations betweenurban land and IS and water-qualityvariables were similar in both regions with differencesin unitless correlation coefficients ranging from 0.00 to 0.06. Compared tourban land and agriculture, relationships between most water-qualityvariables andaltered land were stronger in the south. The extent of urban and agricultural lands inthe watersheds did not differ by region. Altered land was correlated with urban land inboth regions and with agriculture only in the south. Although focused on New Jersey,this study has broader implications for watershed planning.