LEMN Workshop 4.5B - "Lake Erie Land and Water - Clarifying the Urban - Eutrophication Linkage" was a binational workshop that was held at the Upper Thames River Conservation Authority, London, Ontario on April 25th 2014. This workshop was sponsored by Sponsored by Environment Canada (Lake Erie LAMP) through the Lake Erie Millennium Network.

Workshop Resources

Workshop Purpose

Recent manifestations of eutrophication in Lake Erie have become increasingly prevalent, despite evidence that total phosphorus loadings are at or near target levels that previously were deemed adequate to prevent appearance of nuisance algae, hazardous algal blooms and other manifestations. Findings of various task groups and symposia suggest that changes in the form rather than just the quantity of phosphorus may be responsible.

Postulated sources include changing agricultural practices, increasing discharge from urban centres, and/or transformations or altered cycling by in-lake processes: see Workshop 4.2

In February 2009, the Water Quality Board of the IJC and LEMN convened a workshop to assess the weight of evidence supporting each hypothesis.

Possible causes and ultimate endpoints were summarized by participants in a series of flow charts (fuzzy cognitive maps (FCMs) designed to graphically represent understanding and uncertainties about the processes. Both urban-related functions and agricultural activities may be significant external drivers of the reappearance of eutrophication, and likely play an especially important in the Lake Erie ecosystem.

In March 2010, we convened a workshop to improve the resolution of postulated relationships between agricultural activities and eutrophication: see Workshop 4.4. Practices related to agriculture are possibly more amenable to 'no regrets' management actions than other postulated causes of the eutrophication issue.

Workshop Goal

This workshop (a complement and refinement of one convened in March 2013) will further our current understanding of the causes and consequences of the reappearance of eutrophication, emphasizing the potential role of urbanization on the Lake Erie nearshore. The goal is to develop a detailed fuzzy cognitive map that focuses on the urban-related, land-based pathways and variables that have the potential to influence eutrophication in Lake Erie.