This Request for Applications (RFA) solicits applications from eligible entities for a cooperative agreement to be awarded pursuant to the Great Lakes Restoration Initiative Action Plan II (http://glri.us/actionplan/pdfs/glri-action-plan-2.pdf). Applications are requested for a project to 1) provide in situ observational data for use in 2) the development of enhanced Cladophora growth models to enable phosphorus targets to be developed for the eastern basin of Lake Erie as well as for Lakes Michigan, Huron and Ontario. A consortium of investigators will establish sentinel monitoring sites in Lakes Michigan, Huron, Erie and Ontario for one or more growing seasons. In situ observational data collected at these sites will be used in enhanced Cladophora model development. This RFA is one of several funding opportunities available through federal agencies under the Great Lakes Restoration Initiative (“GLRI” or “Initiative) for FY2017.