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| January 12, 2020 Post 110 |
| Softer Shore Defense |
Steel and concrete have long been the go to solution for coastal erosion in the U.S. But erosion supplies the sand and gravel that makes up the beaches which in turn protect the shore from further erosion. When the beach disappears, shoreline erosion rates increase. A very expensive solution now seen in southern California, Florida, and other heavily developed “hardened” coastal areas, is that of pump and dump. Sand is sucked up from the bottom and transported to the beach-less shore and deposited. It’s a temporary solution that is extremely costly and environmentally disastrous for the area that the sand is taken from.
Because of the huge costs, engineers are now seeking ‘softer’ solutions on our saltwater coasts.
Unfortunately, I don’t know of anyone doing this on Lake Ontario’s open shoreline. We don’t have oyster bars and tides. But some people are using more ecology friendly approaches to stabilize the shores of the protected embayments where the wave energy is much lower than along the open lake.
When there is no ice cover on the bays, a lot of the biggest waves are generated by power boats on weekends. Regardless of their origin or timing, even small waves nibbling away at bay side lawns are understandably alarming to the land owners. So the people start hollering for some help from the tax payers for sea walls or a load of rocks out in front of their ‘cottages’.
So what’s wrong with that? you ask. Aside from destroying nice little places to haul your kayak or dinghy out on, not much as far as human use goes. But that delicate changeable interface between bay and lawn is vital to for a number of non human bay inhabitants who must travel between water and land. People who enjoy nature watching, fishing, or hunting are aware that various amphibians, waterfowl, and other critters need to be able to haul out. Wildlife may require access to the shore for food sources. Some critters require spots to bask or call for a mate from. Turtles have to come ashore to b
Numerous birds and fishes make use of the shifting shallows adjacent to the land. A gradual drop off that can be colonized by cattails, reeds, flowering plants and other aquatic vegetation is crucial to the survival of at least a dozen species of fish including game species like the yellow perch and pike, as well as to water birds like the herons that feed on fish as well as to aquatic insects that are vital members of the food chain.
A seawall with deeper water next to it cuts off all this exchange between land and water. Angularity simplifies the landscape and lends itself to the tidy straight lined aesthetic favored by many humans. Without shallow water and access to land, the abundance and variety of bay life declines. Fewer little green and big blue herons stalk the shallows. Fewer ospreys and eagles soar over the bay and lake shore. And fewer fish respond to the angler’s casts. The rich life of the inshore waters is g
Solutions:
A “softer” shoreline stabilization is far cheaper than a seawall and can be installed by the home owner.
The NY DEC website has detailed instructions on how to create a soft defense. Planting low growing native shrubs like the red osier dogwood or the button bush creates a dense network of roots to hold soil. They can be trimmed so as not to block waterfront views, while their foliage provides shelter and habitat. Some native shrubs like the button bush and the swamp loosestrife also have handsome flowers as do many wetland perennials like the native blue iris, the marsh mallow, and swamp milkweed.
Rooted wetland plants like cattail and pickerel weed and the various reeds and sedges help absorb wave energy before it hits the shore. Gradual slopes also help dissipate wave energy that in turn reduces erosion and if space allows trees like the willow, cottonwood or the smaller native alders are excellent ‘anchors’
Native vegetation strengthens the shore’s structural integrity and prevents the land from breaking apart and washing away. The deep roots bind the earth together, while their foliage and branches reduce erosion caused by rainfall and winds. A shore planted in grass easily weakens and crumbles into the water when assaulted by constant weekend boat wakes or the occasional windstorm.
For any home owner reading this post, there are many excellent resources on line. The NY DEC website has a concise but comprehensive ‘how to’ at the URL below. Or simply search for “shoreline stabilization freshwater” for photos and text on how to do it.
Fringes of native vegetation along the bay shore also help reduce storm water runoff and nutrient inputs into the bay. This in turn makes toxic blue green algae blooms less likely- a win win for wildlife and property owners alike.
https://www.dec.ny.gov/permits/67096.html