Erosion

EROSION

The shoreline, where water meets land, is where your waterfront property is most susceptible to erosive forces. Erosion is a natural process that causes a gradual wearing away of land surfaces by water, ice and wind. Erosion can cause slumping, surface runoff, silt deposits, and if left unchecked, major property and building damage. Protect your shoreline by understanding the value of the “buffer zone”. Alterations to your natural shoreline i.e. removal of rocks, trees, and other live and fallen vegetation, puts your buffer area at risk of becoming an “erosion zone”. Being aware of erosion risks and taking appropriate action will better arm you to safeguard your property, and protect your pocketbook.

FAQ

1. What is a “riparian area”?
2. I have a serious erosion problem on my ocean front / creekside / lakefront property. What should I do?
3. I’ve just restored my lakeshore and planted a lot of small shrubs and willow stakes; how do I prevent the plants from being washed away by boat wakes?
4. What is a buffer strip/zone and why is it important?
5. I am considering installing a shorewall on my property. Can you give me some information about what to consider?
6. I have a shorewall on my property which I am told is contributing to erosion elsewhere along the shore. Is there anything I can do?

1. Riparian areas are the narrow strips of land located along marine and freshwater shorelines, whether they are located along oceans, estuaries, lakes, reservoirs, wetlands, ponds, canals, sloughs, wooded draws, rivers, streams, creeks. They also include the sides of dry-bottomed gullies where sub-surface moisture is present, and even human-made drainage ditches. These areas are also often transition zones - the “vital edges” where land and water meet to create unique and often highly productive ecosystems.

2. For most erosion problems, and particularly for extreme ones, we recommend that you retain the services of a professional consultant to analyze your problem and offer sound solutions. Look for engineers, geologists, or hydrologists who are familiar with “soft-shore protection”, also called “soft armouring” or “bio-engineering”. Even if your problem is fairly minor it will be worth the cost of a consultation for the peace of mind. Don’t try to design shore protection yourself. Choosing the wrong approach can be an expensive and sometimes damaging mistake! It can backfire on you (or your neighbours), possibly damage fish or wildlife habitat — and even result in fines!

3. To reduce erosion from boat wakes, reduce the speed of your boat when approaching the shoreline. You can post a sign which indicates the shoreline is being restored and asks people to reduce their speed and wake. In addition, you may want to use several buoys to keep passing boats at a distance.

Be sure to leave driftwood, rocks and fallen trees in place along the shoreline to absorb the wave energy. You can consider adding these sorts of materials along the waterfront and using them to mulch amongst your shrubs with rocks, driftwood, or branches. Securing a log to the shoreline or anchoring it slightly offshore will also help to break the force of the waves.

If you have an actively eroding shoreline, you will need to consider soft-shore protection measures that use control blankets, mulches, and landscape fabrics to help retain your soil while your plantings are taking root. There are many specialized materials being developed. Consult with experts to ensure you take advantage of the most up to date knowledge in this rapidly advancing field.

4. Deep rooted vegetation such as tall grasses, shrubs, and trees, and aquatic vegetation such as reeds or cattails (freshwater) and eelgrass (saltwater), help “buffer” the shoreline. By reducing the energy of waves and currents, the buffer zone protects your shoreline from erosion.

Vegetation covering your property, including in the buffer zone, provides protection from erosion damage caused by surface drainage. Because shoreline properties are on the receiving end of uphill drainage, this is a common problem; the more cover, the better for you.

If properly established and maintained, a buffer zone can:

• remove up to 50 percent or more of fertilizer chemicals and pesticides
• remove up to 60 percent or more of some bacteria
• remove up to 75 percent or more of sediment (soil particles)

Vegetation, logs and rocks along the shoreline also slow down flood waters, reducing damage to your property. In addition, these shoreline plants increase the soil’s ability to absorb water, which reduces the negative impact of flooding.

5. Sometimes when we buy waterfront property with a natural shoreline, we think that we need to put in a retaining wall or bulkhead to reinforce and protect the shoreline from eroding in the future. Unfortunately, this usually helps create the very problem that we fear!

As well as interfering with currents along the shore and contributing to erosion, “hardened” shorelines also eliminate the filtering qualities of a natural shoreline, degrade water quality, destroy habitat for fish and wildlife, block wildlife access to and from the water, and scour beaches.

If you are considering installing a retaining wall along your shoreline to create a flat “usable space” for outdoor furniture like patio chairs and tables, explore some alternate ways of obtaining usable outdoor space for your recreational activities. For example, a firepit close to your house may provide you and your family with many hours of enjoyable evening activity. Or, a couple of hammocks under a shady tree in your yard may provide you with more entertainment than an area close to the water’s edge.

If you are considering installing a shorewall to deal with shoreline erosion, obtain the advice of a professional who specializes in “soft shore protection”.

6. If your shoreline has been hardened with rock or a retaining wall, there are some simple things you can do to “soften” it:

• Restore or plant deep-rooted vegetation along the strip leading to the retaining wall; this will help buffer surface water from runoff and reduce the risk of erosion by holding the soil together.
• Plant overhanging native shrubs to help keep water cool. You can also drill planting holes from the side and plant cuttings or container plants.
• In rip rap, plant shrubs in open spaces among the rocks.
• Anchor a log or two at the base of a retaining wall to improve wildlife habitat and help break the force of water. This will help reduce the scouring action of waves breaking against the wall.
• With approvals, you can add rock rip rap to the base of a retaining wall at a 45 degree angle, to help break the force of waves and improve habitat for fish and wildlife. Gradually sediment may start to deposit amongst the rocks, and aquatic plants may grow.
• Shore “ladders” of rip rap from the base of the wall to the top may be feasible for some walls, again with appropriate approvals from DFO or relevant ministries in your province. These will help provide wildlife (such as amphibians) access from the water to the land.

If your retaining wall is beginning to crumble, consider replacing it with a more shore-friendly structure. However, this must be done without causing further disturbance to your shoreline. Obtain professional advice and obtain approvals from DFO and relevant ministries in your province. Here are the basic steps to “retiring” a retaining wall:

• Dig it out: Get in behind the wall to remove the supporting backfill and then grade to a new slope of 25◦ or less.
• Clothe it: Lay geotextile filter cloth on the slope to hold the soil in place.
• Remove the wall: Ideally, the wall would be physically removed; however, if this is infeasible, break the wall into pieces to lie on the slope. Finally, smash it into smaller pieces of concrete rubble.
• Add more rip rap. This will help aesthetically, and fill in spaces left by the concrete.
• Revegetate: Plant woody vines or shrubs over the top. Gradually, these will grow and look more like a natural shoreline than the vertical structure that was there.

The new structure dissipates the energy of waves and currents.