How many samples were collected at each site?
Water samples were collected from streams throughout the year, including high-flow and low-flow conditions. Sampling was most intensive during the time of highest pesticide use and runoff—generally weekly or twice monthly for a 4- to 9-month period. During the active study periods in each Study Unit, most sites were sampled 20 to 40 times a year, with the most intense sampling during the seasonal periods of highest pesticide use. Data analyses for ground water was based on one sample per well. Repeated sampling, such as that conducted at stream sites, was not included for ground water because of the comparatively slow rate of change in most ground-water systems, relative to streams.
