Bacteria and nutrients from dairies and cropland were impairing recreation in St. Albans Bay (Vermont). The RCWP project focused on manure management and cropland protection BMPs. Manure logs and interviews with farmers were used to monitor land management and document reductions in nutrients and bacteria. Water quality monitoring data indicated a downward trend in stream bacteria counts with an increasing proportion of watershed animals under manure management BMPs.
MONITORING EXPLANATORY VARIABLES
High sediment loads from irrigated cropland and streambank erosion were impairing salmon spawning and recreation in the Rock Creek (Idaho) project. Explanatory variables monitored as part of the 10-year upstream/downstream monitoring program included stream flow and precipitation. These variables were used in the analysis to adjust for climatic variability. In the Taylor Creek - Nubbin Slough (Florida) RCWP project, changes in dairy cow numbers on a subwatershed basis, water table depth, and upstream phosphorus (P) concentrations were the most important explanatory variables. Water table depth measurements in poorly drained, coastal soils were responsive to antecedent rainfall. These measurements were especially useful in confirming that total P concentrations in tributaries increased as the water table rose to within two feet of the surface. Incorporation of explanatory variables in the analyses helped demonstrate that BMP implementation contributed significantly to the decreased P concentrations in tributaries draining into Lake Okeechobee.