Lakeshore Capacity Assessment: Balancing Development and Water Quality in Cottage Country
The Precambrian Shield is Ontario’s largest ecozone, comprising about 60 per cent of the province’s land area and over 250,000 inland lakes. Many lakes on the Precambrian Shield are characterized as oligotrophic (i.e., low in primary production due to low nutrient levels). As phosphorus is the nutrient most often limiting primary productivity, these lakes are sensitive to its introduction. Increases in total phosphorus concentrations are associated with higher levels of algae and plant growth, which can lead to decreases in oxygen concentrations (the process of eutrophication) in a lake’s deep waters. These low oxygen conditions are harmful to cold-water fish, such as lake trout. In most Precambrian Shield lakes, septic systems of residents, cottages and other shoreline developments are the primary human sources of phosphorus.
The Handbook describes a mathematical model to determine a maximum allowable load of phosphorus from human sources to inland lakes on the Precambrian Shield. The model can also be used to predict the level of additional development that can be sustained around a particular water body without adverse effects due to phosphorus. Municipalities and planning authorities can use this model and the information it provides to determine how many lots should be permitted along the shoreline of a lake. If lakes are already above capacity, MOE suggests that municipalities limit planning approvals for new developments.
Although municipalities are not required by law to carry out lakeshore capacity assessment, an assessment is “strongly recommended” by the Ontario government as a means of being consistent with the Planning Act, the Provincial Policy Statement, 2005 (PPS), the Ontario Water Resources Act and the federal Fisheries Act. MOE states that implementing a lakeshore capacity assessment will require the co-operation of the various ministries and agencies involved, but that municipalities and planning authorities are ultimately responsible for carrying out modelling and setting capacity limits.
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Implications of the Decision
More Stringent Phosphorus Objectives
In the Handbook, MOE has redefined the maximum allowable levels of phosphorus in Precambrian Shield lakes to a 50 per cent increase in phosphorus levels for each lake, calculated from a modelled baseline of “water quality in the absence of human presence.” The new model considers cumulative effects of downstream phosphorus transport in the context of the watershed. Under the new approach, each water body has its own phosphorus objective, so sensitive lakes will be treated more appropriately than in the “one size fits all” type approach previously taken.
Limited Support for Implementation by Municipalities
The Handbook makes it clear that the onus is on each planning authority to implement lakeshore capacity planning, and MOE will provide technical or educational support when asked. The Handbook does not outline any new ministerial responsibilities or financial assistance from ministries. The Handbook notes that some municipalities may not have experts on staff, but that resource managers, planners and environmental engineers could be trained to use the Lakeshore Capacity Model “in less than a week.”
Lack of Incentive for Best Management Practices
The lakeshore capacity model does not take into account any best management practices that encourage retention of phosphorus before reaching the lake. Several lot-level practices, such as the use of vegetated buffer strips as nutrient sinks, are understood to reduce phosphorus entering lakes. MOE did not include these voluntary practices in the general model, calling for further research as few long-term studies have been published providing quantitative evidence of their benefits. Municipalities would need to undertake additional site-specific research before including best management practices in the lakeshore capacity model. Since the general model does not factor in any benefits of best management practices, there is little incentive for municipalities to encourage these practices.
Lakeshore Capacity Model’s Focus on a Single Indicator
Lakeshore capacity assessment as described in the Handbook addresses only one pollutant – phosphorus. It does not account for any other factors that contribute to a lake’s capacity: pollutants other than phosphorus; specific sources of pollution; or factors outside of water quality. By contrast, the original lakeshore capacity assessment approach from the 1980s examined a range of indicators to predict the environmental change resulting from development, including: land use; fisheries exploitation; wildlife habitat; microbiology; and water quality.
ECO Comment
The ECO is pleased that MOE released this Handbook, which was several decades in the making. The Handbook clearly explains the lakeshore capacity model, as well as when and where municipalities or planning authorities should apply it. Further, the ECO is pleased that the model provides a quantitative, more site-sensitive tool for watershed-level planning. The ECO commends MOE for developing new, more stringent limits for phosphorus concentrations for inland lakes on the Precambrian Shield, and encourages MOE to consider updating the water quality objective for total phosphorus across the province.
However, the ECO has observed a substantial retreat by the government from the previous comprehensive method of shoreline capacity planning. The ECO believes that the current approach, focused solely on a single nutrient, takes a narrow approach to the concept of “capacity.” Despite the importance of phosphorus as a key indicator of lake water quality, it should not be the only factor in determining the level of development allowable on a lake. Further, it appears that although provincial guidance is available, the government has downloaded key responsibilities for lakeshore capacity assessment to municipalities with no new funding and limited technical support.
A mechanism to monitor the adoption and effectiveness of the lakeshore capacity assessment appears to be lacking. Without a legal requirement, funding, or assurance of ministry support at the Ontario Municipal Board, many municipalities may choose to go slow or ignore this new guidance. The ECO believes that ministries have a clear responsibility to support municipalities in their adoption of lakeshore capacity assessment; the ECO urges MOE, MMAH and MNR to establish a working group and specify a timeline for reviewing the Handbook and its effectiveness going forward. For example, ministries should commit to report to the public on municipalities that have adopted this form of lakeshore capacity assessment within three to five years.
The ECO questions why, after over 25 years of research, MOE still does not have the quantitative information necessary to include best management practices in lakeshore capacity assessment. The ECO suggests that MOE, MNR and MMAH commit to completing the necessary research to incorporate best management practices in updated versions of the model, thereby encouraging a suite of actions to reduce phosphorus loading to Ontario’s inland lakes.
| Recommendation 6:
The ECO recommends that MOE update the Provincial Water Quality Objective for Total Phosphorus to reflect individual lake sensitivity and watershed-level cumulative effects. |
For a more detailed review of this decision, please refer to Section 4.2 of the Supplement to this Annual Report. For ministry comments, please see Appendix C.
| Previous section: Lake Simcoe Phosphorus Reduction Strategy: Is it Enough? |
| Next section: Stormwater: Our Neglected Headwaters |
| This is an article from the 2010/11 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2011. "Lakeshore Capacity Assessment: Balancing Development and Water Quality in Cottage Country." Engaging Solutions, ECO Annual Report, 2010/11. Toronto: The Queen's Printer for Ontario. 66-68.
