Dave is the founder and director emeritus of the Water Quality Laboratory at Heidelberg University (now the National Center for Water Quality Research). Since its onset in 1969, the research program has focused on quantitative studies of nutrient and sediment transport in rivers, primarily within the Lake Erie Basin. The resulting data support (1) determination of the agricultural contributions to watershed-scale nutrient export to Lake Erie, (2) development of appropriate agricultural pollution abatement programs, and (3) assessment of the effectiveness of those programs. In his presentation, Dave will review the methods used to separate the size of agricultural and municipal phosphorus sources impacting Lake Erie and the evidence supporting the need to focus agricultural pollution abatement programs on dissolved phosphorus via nutrient management rather than particulate phosphorus via erosion control programs. Data on phosphorus stratification in soils as a cause of increased dissolved phosphorus runoff will be presented. Differences between dissolved phosphorus and nitrate export from agricultural watersheds, relative to legacy issues will also be discussed.