Automated Storm Water Sampling on Small Watersheds

Few guidelines are currently available to assist in designing appropriate automated storm water samplingstrategies for small watersheds. Therefore, guidance is needed to develop strategies that achieve an appropriate balancebetween accurate characterization of storm water quality and loads and limitations of budget, equipment, and personnel. Inthis article, we explore the important sampling strategy components (minimum flow threshold, sampling interval, and discreteversus composite sampling) and project -specific considerations (sampling goal, sampling and analysis resources, andwatershed characteristics) based on personal experiences and pertinent field and analytical studies. These components andconsiderations are important in achieving the balance between sampling goals and limitations because they determine howand when samples are taken and the potential sampling error. Several general recommendations are made, including: settinglow minimum flow thresholds, using flow-interval or variable time-interval sampling, and using composite sampling to limitthe number of samples collected. Guidelines are presented to aid in selection of an appropriate sampling strategy based onusers project -specific considerations. Our experiences suggest these recommendations should allow implementation of asuccessful sampling strategy for most small watershed sampling projects with common sampling goals.