A new paper was published in the journal Ecological Indicators by ERG researchers Chris Wellen (now at Ryerson University) and Philippe Van Cappellen, together with colleagues from the Ontario Ministry of Environment, Conservation and Parks and Environment and Climate Change Canada. In this study, the authors estimate the sample sizes required to detect statistically significant changes in annual nutrient loads and flow weighted concentrations brought about by conservation measures in agricultural watersheds. The analysis is based on data of long-term flow and water quality from 13 temperate agricultural watersheds spanning a gradient of size from 11 – 16,000 km2 using data synthesized from long term flow and water quality records. The results should help watershed monitoring programs to design sampling regimes that yield adequate statistical power.
The paper can be found here.