Whether building a house, gazebo or dock, any construction project that takes place near water requires special care. When building on shoreline property, it increases the potential to damage land, pollute nearby water, and reduce your property’s overall appeal. Before you start any construction project, plan wisely to avoid costly problems. Your waterfront property has many unique characteristics; remember to take them into account!
- I would like to clear my property before I start building but my neighbour has told me this will damage water quality. Is this true?
- I am considering installing a shorewall on my property. Can you give me some information about what to consider?
- 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?
- How can I protect water quality during construction?
- What are some tips for managing drainage on my property?
- How can I protect trees on my property during construction?
- What are some key elements I should include in my site building plan?
- I am worried about drainage on my property. How can I avoid building on an area that has excessive moisture?
- What can I do to minimize the damage done to my shoreline property during construction?
1. Clearing not only could damage water quality – you could lose topsoil to the water. When bare ground is covered with plants, including the shoreline buffer zone, it helps reduce damage and erosion caused by surface runoff. Vegetation also helps keep pollutants out of the water.
Because shoreline properties are on the receiving end of uphill drainage, erosion from rain and snow melt can be a common problem, so the more vegetative cover, the better.If properly established and maintained, a shoreline buffer zone will:
* 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
When dirt particles are carried by runoff and deposited in surface water:
* sunlight cannot penetrate the murky water and aquatic plants are unable to grow, thus destroying habitat for aquatic creatures.
* gravel, pebble or sand beds are covered, making them unsuitable for fish spawning and as homes for insects such as mayflies and stoneflies.
* treatment costs for drinking water can escalate.
* water becomes less pleasant for swimming.
Instead of clearing your property, consider leaving a wide buffer of shoreline plants, and clear only what you need for your access road, buildings, and sewage treatment system (if you are not connected to a municipal system). Leaving a buffer zone will help protect your property from erosion from waves and currents as well.
2. 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”.
* 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.
4. To protect water quality during construction, you will need a two fold strategy. First, keep clean water clean (ie. by stopping it from running through your construction site) and second, keep any water that does become dirty from entering clean water (for example, flowing downhill straight towards the nearest waterbody).
* Place silt fencing downhill of your building site. This fine material allows water to escape while catching soil particles.
* Use temporary hay bale dyking uphill of your building site. Hay bales can be used to direct runoff while catching soil.
* Near water bodies, use only clean fill which is free of debris, such as rock, sand or gravel.
* Cover fill piles (eg to be used for backfilling the basement foundation) with tarps. Uncovered fill will erode away, making a mess of your site and destroying wildlife habitat. Avoid extended use of plastic and tarps, however, as they also will cause increased runoff which can lead to erosion elsewhere.
* Check your site after major rainfalls and correct any erosion problems. If possible, go on site during a storm and observe what is happening to runoff.
* Make sure your equipment is in good working order, to avoid leaks of fuel, oil, etc. which could contaminate surface water. Monitor it regularly.
Protect bare ground
It is critical to protect exposed soil from wind, rain and other sources of soil erosion.
* Leave ground covered until it really must be uncovered.
* Promptly cover soil that has been exposed.
* Keep as much of the construction site covered at any one time as possible; minimize disturbance of ground cover like shrubs or grasses to avoid exposing soil and causing erosion or potential slope failure.
* Cover bare ground with mulch or burlap to limit erosion. Hold mulch down with nylon netting. If possible, mulch bare ground at the end of every day.
* Use hay or straw as a mulch to cover disturbed areas after reseeding. A good rule of thumb is one 50 pound bale per 500 square feet / 45 square metres.
5. Every waterfront property has some degree of surface and groundwater flow. Although you will never be able to control these water flows entirely, you can do your best to manage them so they are not contributing to accelerated erosion and landsliding along your waterfront.
* Reduce runoff towards steep waterfront slopes.
* Divert surface runoff away from steep slopes with narrow gravel filled trenches.
* Outlet rain gutters and road run-off logs (water bars) to the side of a slope.
* Minimize paved and other hard surface areas such as building roofs and patios. Use gravel, modular paving stones, flagstones or decay resistant wood blocks for paths and patios. Modular paving stones provide the durability of concrete while allowing rainwater and snowmelt to filter into the ground; however, they do require maintenance to clean away silt. Do not pave areas that will serve no useful function (such as the corner of a building).
* Use swales (gentle depressions in a slope), berms (low ridges), haybales or other devices to redirect water.
* Design your drainage system to help surface runoff water slow down, with curves (lined with rocks if necessary) and settling pools. This will also give sediment a chance to settle out. Avoid straight ditches heading directly for the water.
* Install eavestroughing along the edge of rooftops to help carry water off the roof and away from the building to areas where soil will not be eroded.
* Provide erosion protection (like a pit and drain trench filled with drain rock) where the down spout outlets onto soil.
* Wherever possible, keep existing natural vegetation or enhance it with landscaping.
* Never run a drainage pipe to the edge of a ravine, bluff or bank.
* Work with your neighbours to create a mutually satisfactory plan for handling runoff. Avoid having your runoff spill onto their property.
Even where your circumstances may require major shoreline stabilization efforts, dealing with your site’s drainage is still an essential component of your strategy for dealing with erosion.
6. Trees are often damaged during construction and then die later. The major problems are grade changes around trees, soil compaction and injuries such as gouging caused by heavy machinery, and tree thinning. The extra initial expense of careful site development to avoid these problems is a worthwhile investment.
* Use temporary fencing to protect trees and shrubs from damage by construction vehicles. This will prevent root damage, gouging and soil compaction (which cuts off air and water to roots).
* Keep all digging and excavation at least 3 m (10 ft) from any tree you want to preserve. Roots generally extend out at least as far as the branches (the “drip line”).
* To avoid soil compaction around trees, hand clear brush surrounding trees rather than using heavy machinery.
* Do not bury tree roots when backfilling or grading. Even 15 cm (6 inches) of fill over the existing grade can cause the death of a mature evergreen.
* Attend to any damage. Damaged roots, trunks, and limbs can cause major trauma to a tree. Support or remove damaged limbs and maintain root cover by adding soil or mulch when necessary.
* Discuss with your contractor how to protect existing drainage patterns as much as possible in order to maintain the same water flows to the vegetation you are protecting.
* Understand the natural features and processes unique to your property and choose building sites and designs that are compatible.
* Locate your high water mark and check for any floodplain restrictions or conservation easements.
* Check with your municipality or Conservation authority for local zoning regulations, development permit requirements and minimum setbacks from water.
* Site your well and septic system first, and identify any environmentally sensitive areas such as wetlands to protect.
* Choose a building site requiring minimal clearing of trees and shrubs, as far back from the shore as possible (min. 30 m or 100 ft), further back on steep sites or where special regulations require.
* Leave a buffer strip of natural vegetation at least 30 m wide along the shoreline. Keep well back from edges of bluffs and crests of ravines.
* Focus alterations like a path, dock or boat launch in one area of your shoreline. Leave as much as possible natural.
* Plan roads and driveways to minimize site clearing and erosion.
* Divert and slow the flow of rainwater and snowmelt to prevent moisture and erosion problems.
* Prune or limb trees instead of removing them entirely to open up views to the water.
* Build to discourage wildlife from sharing your home. In return, consider enhancing wildlife habitat elsewhere on your property.
8. Excess moisture seeping into your building can mean potential for rot, cracked foundations and musty odours. Before you build, check your site in the spring. If there is strong underground seepage in this area, look for alternative locations that are drier, or, if you must build there, install a double weeping tile system.
* Hire qualified contractors who will respect your land and your plans; use written contracts to clearly outline responsibilities and expectations.
* During construction, block off the shoreline and use temporary fencing around trees and shrubs to prevent damage by construction crews.
* Always have a “Green Bin” on hand to clean up spills when they happen. It should include rags, absorbent materials like kitty litter or sawdust, a trowel, empty plastic containers with lids, and crystals for hardening spilled paint (available at hardware stores).