Monthly Archives: July 2019

Integrated watershed management can manage Muskoka’s environment

By Peter Sale


Photo by John McQuarrie


In a previous article, Kevin Trimble proposed using watershed hydrology to help manage floods. How do we do this?


The Muskoka Watershed Council recommends integrated watershed management if we want long-term success. Integrated watershed management is widely used in North America and overseas, but not yet in Muskoka.


Nature is interconnected; every organism, every physical feature, every process. What happens in the forest ends up in the lake, upstream ends up downstream, and what happens downstream can even affect what happens upstream. A watershed is a natural management unit which captures precipitation, filters and stores water, and regulates its release as river flow.


The Muskoka River Watershed, stretching from the Algonquin Highlands to the outlets of the Moon and Musquash Rivers at Georgian Bay, includes nearly all the District Municipality of Muskoka, as well as portions of Algonquin Highlands and Seguin Townships, a total of 4,660 kilometres squared. Over half the precipitation arriving in this watershed never gets to Georgian Bay; it is trapped in soils, trees and groundwater or evaporated back to the sky. The rest sometimes causes floods.


Integrated watershed management begins by recognizing that water quality as well as quantity or flow are strongly dependent on the nature of the watershed: its topography, its natural infrastructure of soils, forest types, ground cover, wetlands, rivers and lakes, and its human infrastructure of roads, parking lots, buildings, bridges, channels and dams. Built infrastructure for managing river flow plays an important, but minor, role in how water moves through our watershed. Even if it were possible, it would be far more costly to attempt to manage flow entirely using built infrastructure; we must also use natural infrastructure. In addition, nutrients and pollutants move with the water, playing major roles in determining environmental quality of both the land and water. Flow management is far more than engineering of some river channels; it’s a central part of integrated environmental management.


To implement integrated watershed management in Muskoka, all levels of government, economic sectors and the community must have seats at the planning table, and regulatory agencies and municipalities must ensure their individual actions become part of a seamless, watershed management process.


Muskoka’s long experience with co-operative approaches to environmental management makes integrated watershed management a particularly good fit, and provincial funding promised in 2018 for Muskoka’s environment permits an immediate start. A GIS-based inventory of man-made and natural infrastructure is the first step for modelling the watershed’s hydrology and its capacity to store and move water. Developing a fully interactive hydrological model for use in guiding management decisions is the next step. Such a model provides managers with a vital tool to ask the “what if” questions around the consequences of any planned actions. The model also reveals consequences of events beyond our control such as those caused by global climate change. If we want to minimize future flooding and sustain Muskoka’s environment, we have to take an integrated watershed management approach.


The good news is that much of the needed environmental inventory and some records of precipitation and river flow are already available. Data need to be brought together and augmented as needed to commence the comprehensive hydrological study that will deliver the interactive model. These initial steps require a targeted research effort that could best be met by engaging university-based researchers in collaboration with relevant management agencies.


With integrated watershed management in place, managers will better understand the factors driving water flow, and be able to incorporate that knowledge into all planning decisions, including decisions for any future flow control infrastructure. Integrated watershed management will help ensure nature is thriving alongside a robust Muskoka economy and lifestyle, plus cost-effective management and fewer unpleasant surprises when spring comes around each year.



We need more than just an update to the Muskoka River Water Management Plan

By Kevin Trimble, MWC Chair


Mary Lake Dam


The “Flood of 2019” is now a common term in Muskoka. In its aftermath, there has been an urgent need to focus political will and resources on helping people recover their own losses and on fixing public infrastructure. Almost as urgent, there has also been a call to gain a better understanding of the causes of floods and to prepare ourselves to live with the next one.


But how do we do this? Many people are calling for an update to the Muskoka River Water Management Plan (MRWMP) because this plan is out-of-date and deals primarily with the operation of dams in the Muskoka watershed.


But is that enough on its own? The MRWMP was not designed to manage floods. According to MWC’s Patricia Arney, there are many other human and natural features across the entire watershed that should be considered.


Watershed hydrology, which is the study of how water moves across the landscape, both on land and in waterbodies, is needed to create a broader understanding of the origins and management of flows. Watershed hydrology is used to create a water budget, which is like a financial budget where money comes from a variety of sources into our accounts and goes out as expenses.


In a water budget, water comes in through rain and snow, groundwater and flow from upstream. Some of that water soaks into the ground, some goes back to the atmosphere (about half of our annual precipitation is pumped back to the atmosphere by our forests), some is stored in wetlands, and lakes. The leftover water flows downstream.


Now imagine that our watershed is made up of many small pieces of land, like pieces of a puzzle. A water budget can be made for each piece to see how it contributes to the whole. Water coming out of all the pieces collects into small streams, then bigger rivers and lakes.


Each piece of the watershed has its own natural infrastructure to manage the flows that are released. Some pieces have deeper soils for groundwater recharge. Forests to pump water into the atmosphere. Ground vegetation also pumps water and maintains soils and channels. Wetlands store water. Some pieces have been modified or removed by human land uses like development and infrastructure and now produce more excess flow. So how we manage each small piece of the watershed affects river flows and lake levels. But first we need to understand how all of the pieces work and how they fit together.


With poorly managed home finances, debt leads to expenses that allow too much money to flow out too fast.


Good flood management means managing excess runoff from every piece of the watershed, so by the time excess flows get into big rivers and lakes, there is less flood water to manage. An updated MRWMP is only one part of our portfolio. That’s like controlling our chequing account while draining our credit cards, RSPs and savings accounts.


Each corner of the watershed has unique opportunities for flood control if we use a broad watershed hydrology approach to understand how the pieces all work together. We need to assess and conserve all of our natural infrastructure, including wetlands, headwater streams and forests. We also need to look at our built infrastructure in a different light and to consider building new natural infrastructure where it makes sense. We may also need new kinds of controls on how and where we build.


Watershed hydrology forms the backbone of an integrated watershed management strategy which will be the subject of an upcoming article.