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?
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 ) What is a buffer strip/zone and why is it important?
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 ) I am considering installing a shorewall on my property. Can you give me some information about what to consider?
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 fire pit 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 shore wall to deal with shoreline erosion, obtain the advice of a professional who specializes in “soft shore protection”.
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?
- 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.