Your Link to Muskoka's Water!

A geographic template for cumulative-effects assessment in the Muskoka River Watershed
 

Murray Richardson (PI/Carleton University)
Rachel Plewes (MSc/Carleton University)

Some lakes and rivers are more vulnerable to anthropogenic stressors than others. Examples of such stressors include nutrient loading from septage and agricultural runoff, atmospheric pollution such as mercury and sulphur dioxide, and even hydrologic regime shifts linked to global warming.

The Muskoka River Watershed comprises an area of 4,660 km² and more than 2,000 lakes, and it is difficult to predict how sensitivities of individual waterbodies to stressors vary as a function of landscape factors (e.g. watershed physiography, geology, forest type and land-use). However, emerging research in the field of "landscape limnology" has shown that these sensitivities can be predicted with reasonable confidence using new geospatial technologies like GIS and remote sensing, in conjunction with powerful statistical models involving computationally intensive "machine learning" approaches.

The overarching objective of this research project will be to conduct an analysis of historical water quality data from Muskoka River Watershed lakes and rivers and to develop a spatial-statistical model of aquatic ecosystem characteristics and their inherent variability throughout the Muskoka River Watershed.

Geospatial analysis with remote sensing and digital terrain models will be used to generate "Bayesian trees" to statistically model and predict spatial variability in lake and riverine physico-chemistry. This model will subsequently be used as a geographic template to classify all 2,000+ lakes in the Muskoka River Watershed on the basis of chemical and biological sensitivities to key stressors/indicators (e.g. calcium, phosphorous, dissolved organic carbon and chloride).

Finally, a subset of lakes in the Muskoka River Watershed will be surveyed in the summer of 2013 to explore the potential of several simple chemical and isotopic measurements for use as rapid assessment indicators of internal cycling of nutrients and contaminants, which may facilitate future monitoring efforts in this region.

Update - November 2013

 
Some lakes and rivers are more vulnerable to anthropogenic stressors than others. The Muskoka River Watershed comprises an area of 4,660 km² and approximately 615 lakes, and it is difficult to predict how sensitivities of individual water bodies to stressors vary as a function of landscape factors. The overarching objective of this research project is to conduct an analysis of historical water quality data from Muskoka River Watershed lakes and rivers and to develop a spatial-statistical model of aquatic ecosystem characteristics and their inherent variability throughout the Muskoka River Watershed.

Current efforts are focussed on refining input data sources including GIS layers required to extract meaningful information describing the landscape context of each lake within the Muskoka River Watershed. A new sub-objective of this project is to develop a novel technique for estimating lake depths and volumes from the local topography surrounding each lake, with some promising preliminary results. This effort will provide crucial additional information on lake hydrology and residence times, a missing component of many landscape limnology frameworks developed for other North American lake districts. The contextual information about the surrounding landscape of Muskoka River Watershed lakes extracted from these various data sources will be used to develop predictive models of lake water-quality and sensitivities to stressors, such as urban or agricultural runoff and atmospheric pollution.

The above-described work is the focus of MSc student Rachel Plewes in the department of Geography and Environmental Studies at Carleton University.