Caring for Our Shores – Chapter 3: Let Nature Do the Work
…how to minimize harm through careful building and landscaping
Some of the largest alterations we can make to our properties are structural: digging fields for septic systems or channels for water pipes, clearing land for lawns and views, paving, roofing, and removing trees. Although many of these things help us to enjoy our property, they may also lead to potential problems through increased run-off and erosion.
Each time we pave or cover an area with impervious surfaces, we give run-off more travelling distance to cross before it drains into the ground; this reduces infiltration and increases evaporation, lessening the amount of potential groundwater. We also provide it with a smooth place to collect and gather speed.
While a little bit of run-off might have passed through your property unnoticed, greater amounts sweep away soil, causing rills and cracks to develop. Run-off from agricultural or urban areas carries pollutants harmful to groundwater and wildlife; concentrated in large amounts, these can affect your health and the health the shore.
Reducing Impervious Surfaces
Reducing the amount of pavement on your property will help stop concentrated run-off from becoming a problem. If you are building a new house, choosing a taller, multi-storied design instead of a sprawling single level means less ground occupied by roofing.
Upland development affects the drainage of surface and groundwaters by impeding its natural flow or giving it an “easier” route (in the case of buried pipes). Cleared land means less vegetation to act as a buffer against erosion. Not only that, but without the cyclical decomposition of roots, leaves, and organic matter present in forested land, your soil quality degrades rapidly. The ability of poor soil to hold water and nutrients is negligible.
To lessen the impacts of erosion, landowners often erect shoreline structures such as breakwaters, jetties, seawalls, groins, and bulkheads. Some of these actually worsen the problem by disturbing patterns of sediment and nutrient transport or shifting the erosion problem down shore. Seawalls and bulkheads can also eliminate important shallow water habitats and affect water exchange with salt marshes.
Shoreline trees and vegetation perform a vital function: they absorb quantities of water that might otherwise erode banks, taking up excess nutrients and toxins before they reach the sea. They also anchor soil to the substrate and provide stability in steep places. To protect the shore against erosion, try obtaining some of the plants naturally found on your banks from your local native plant nursery.
Some native vegetation particularly good at preventing seashore erosion includes:
- snowberry (deciduous, 0.5-2 m)
- salal (evergreen, 0.2-5 m)
- ocean spray (deciduous, to 4 m)
- evergreen huckleberry (evergreen, to 4 m)
- bigleaf maple (deciduous, to 35 m)
- willow (deciduous, 1-12 m tall)
- yew (evergreen, 2-15 m)
- native plant seed mixes (grasses, deciduous, 0.5-1.5 metres)
To order a copy of Caring for Our Shores: A Handbook for Coastal Residents in the Strait of Georgia, contact:
The Cowichan Community Land Trust Society
#6-55 Station Street, Duncan, B.C, V9L 1M2
P: 250-746-0227, F: 250-746-9607
The Marine Ecology Station
Images used with special permission from Kerry L. Werry. To view more pictures of ocean creatures found in B.C waters, visit the B.C Diving and Marine Life I.D Page.