The objectives of this report were to summarize the various techniques utilized in the Grand River Basin Water Management Study to assess both the extent of the aquatic plant growth in the river and the impact of the plant growth upon the instream water quality. The report also discusses the field procedure and data collection schedules required for such an assessment. Techniques discussed in this report include the estimation of: solar radiation at both the water surface and at the plant depth, biomass density, biomass nutrient chemistry, and productivity and respiration of the plant community. Also included is a discussion on the data interpretation and a recommended field survey required to provide the necessary input for the ecological model, ECOL1, which is described fully in the companion report, Report #14, "Aquatic Plant Model Derivation and Application". Examples of data collected for both the plant community assessment and for the ecological modelling are provided in the appendices.