Natural shorelines protect water quality

Waterfront owners may not realize that the state of their shorelines directly affects water quality. Unfortunately, what happens on the land doesn’t stay on the land – at least not without a buffer zone of natural vegetation to help prevent pollutants and excess nutrients from getting into the lakes.

Kawartha Conservation

Deteriorating water quality is largely the result of too many nutrients, especially phosphorus, in lake water and sediments. On our lakes, most of this phosphorus comes from fertilizer and from septic systems leaching into the soil. So it’s important to stop the nutrients in runoff water and eroding soil from washing into the lake, where they “fertilize” algae and aquatic weeds and pollute the water. It’s equally important to prevent gas and oil and chemicals found in pesticides and herbicides from leaching into the water, because they are harmful to humans, fish and wildlife.

A simple, cost-effective way to help control runoff and erosion is to maintain or restore shorelines with a buffer zone of natural vegetation covering at least the first 5 metres back from the edge of the water. A variety of native species of vegetation – ground covers, wild flowers, shrubs and trees – with strong spreading root systems will slow down the rate of natural runoff and trap nutrients, pollutants and eroding soil before they reach the water.

Taller plants or bushes, rather than a lawn, also discourage geese from coming up on shore, because they love to feed on lawns, and believe predators may be lurking in taller vegetation. Native plants with strong root systems also help prevent shoreline erosion from wave action and boat wakes, and provide habitat for wildlife.

The lake wants a separation from your lawn

Shoreline experts advise that any lawn area should be kept at least 15 metres back from the water’s edge with a buffer zone of natural vegetation between it and the lake.

We recognize that most properties, and families’ needs for play areas, can’t accommodate this, so we recommend keeping lawn areas at least five metres back from the shoreline.

Keep any lawn at least seven centimetres tall to slow down runoff. A lawn is a hard surface and rainwater runs off short lawn grass about twice as fast as off areas with larger plants. No fertilizer, pesticides or herbicides should be used near the water.

A good way to begin creating a healthy natural shoreline is to stop cutting the first three to five metres back from the water. Native plants will begin to appear and you can gradually add more. Another approach is to set aside a portion of your shoreline that is not being used, and begin to naturalize this area.

Wildlife depends on the ribbon of life

The first 10 to 15 metres of shoreland and the shallow water next to it are extremely important to wildlife, and are also key to water quality. Clear scientific evidence now exists showing how shorelines affect water quality, and how essential this riparian zone or ribbon of life is to the survival of almost all species, both in the water and on land.

Lynda Marsh


Ninety per cent of all lake and river life depends on shoreline areas for birth, feeding and survival. Seventy per cent of land animals also depend on shorelines for survival at some point in their lives. Hardening shorelines with concrete shore walls or large stone blocks interrupts this ribbon of life and directly impacts wildlife, while doing little to prevent erosion over the long term.

To find out more about the importance of natural shorelines and how to naturalize yours, see:


Helping owners help their shorelines

Our Council has been providing a shoreline education and evaluation program since 2011, working with various partners and shoreline consultants.

The goal is to help improve lake water quality by making it easier for owners to voluntarily restore a portion of their waterfronts to a natural state.

Janice Sommerville

We have conducted a number of educational workshops about the importance of healthy natural shorelines and how waterfronts can be naturalized.

For several years we invited owners on our lakes to take advantage of our shoreline evaluation program, funded by the Stony Lake Heritage Foundation. Unfortunately, this program has been suspended because we do not currently have a shoreline consultant to carry out new evaluations.

Because natural shorelines are so important to water quality and wildlife, we hope waterfront owners will take the initiative to naturalize portions of their shorelines. Native flowering plants also provide important food sources for bees and other pollinators.

Please click on the links in the section above to access shoreline resource materials, and go to Shoreline Plants on the menu bar for a list of Shoreline Plants to Decrease Erosion.


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