Why 30 has always been the magic measure.
One thing everyone can agree on is that a healthy, natural shoreline is a lake’s strongest line of defence against toxic Blue Green Algae blooms - but there has been a huge amount of debate about just how far back from the water’s edge these natural filters and buffers should start.
There is now a strong consensus among lake-health scientists that the first 30 metres back from any body of water should remain as natural as possible to protect the health of our lakes. Buffers of less than 30 metres will do some of the work, but they simply don't provide the comprehensive protection offered by 30 metres.
Interestingly, the legal requirement of a 30-metre set-back for buildings from our shorelines is not new and has been on the statute books in many Haliburton County townships for years now. It is also standard practice in most municipalities in Ontario.
Getting to the point.
When pollutants enter a lake from a specific and identifiable source such as a factory or a leaking boat engine, this is known as point-source pollution. However, as rainwater flows over our roads, roofs and properties it washes away everything from oil drops leaked from car engines, to pesticides, fertilizers and pet waste. This runoff flows through our gardens and yards, ultimately ending up in our lakes. This wider range of pollutant sources is known as 'non-point source pollution' and is one of the major contributors to the increasing number of algal blooms being recorded in our County's lakes.
Many studies prove that while small buffers (2 to 15 metres) can remove some sediment and phosphorus, literature overwhelmingly supports the fact that larger buffers of 30+ metres provide the most effective filtration and protection for our lakes.
To read the full Lakeshore Capacity Assessment Handbook (LCAH) visit: https://www.ontario.ca/document/lakeshore-capacity-assessment-handbook-protecting-water-quality-inland-lakes
With respect to the 30 metre “ribbon of life” measured from the highwater mark of a waterbody, MOECP Eastern Region has recommended this setback distance for well over 25 years.
Confidence in consensus
For many in our County, establishing and protecting a 30-metre buffer won't be 'new news'. 30-metre setbacks are already a well-established way of life and way of working. Our County and our Townships already appreciate the value of 30 metres and - as you'll see below - have had that number written in to their Official Plans for some time.
Their consensus should give us all confidence in 30 metres being the magic number.
County of Haliburton Official Plan
The County requires, the retention of natural vegetation, including trees, in the full 30 m setback from the high watermark of a ‘body of water’, including rivers and streams on all existing and new lots [MAH Mod 7a]. Local official plans shall identify the minimum requirement for development and site alteration setback from the high water mark. Development and site alteration, including septic system tile beds, shall be set back a minimum of 30 m from the high water mark of lakes, rivers and streams, with no disturbance of native soils and very limited removal of shoreline vegetation. Local municipalities may use planning tools and by-laws to limit encroachment of development on the respective surface water feature(s). Section 188.8.131.52
Municipality of Highlands East Official Plan
Site alteration and disturbance of vegetation is not permitted within the 30 metre setback except for minor alterations to accommodate access trails, docks, water pumping equipment or restoration work.”
Municipality of Dysart et al Official Plan
Within shorelands, all buildings, structures, and tile fields will be set back at least 30 metres from the high water mark of lakes and rivers, and streams.
Township of Algonquin Highlands Official Plan
In general, development and site alterations should be set back a minimum of 30 metres from the high-water mark of lakes, rivers and streams.
Township of Minden Hills Official Plan
Setbacks are utilized to attenuate phosphorus loadings from storm water as well as to maintain the natural integrity of shorelines, including fish and wildlife habitat. Setbacks are also utilized to reduce or soften the visual impact of development on a lot. Vegetation within the setback should be disturbed as little as possible, and the soil mantle should not be altered.