North Shore Erosion Control
(click on any image to enlarge)
There is no question that erosion on the north shore needs to be stopped, in some places the bank has been eroded back 4 – 5 meters, and the walkway itself is threatened. There are two competing visions as to how this erosion will be checked: armour stone or bio-engineering.
The armour stone solution recommends the placing of heavy large stone or concrete blocks along the shoreline from the Festival Bridge to the Orr Dam. The advantage of this approach is that it is very permanent and will stop erosion — witness the stone wall protecting Tom Paterson Island.
Unfortunately, there are three major disadvantages: First, it is very expensive. According to the retained consultant’s presentation to subcommittee on August 2006, it would cost almost two million dollars to supply and install armour stone from Festival Bridge to the Orr Dam. Second, armour stone or concrete present a sterile appearance and provide no habitat for wildlife as compared to natural vegetation. Third, and most important, stone and concrete do not filter or clean the water, whereas natural vegetation does filter out pollutants.
AREA strongly advocates the bio-engineering solution and recommends the following:
- An uncut buffer zone between the cut lawn and the top of the bank to slow runoff and absorb pollutants.
- The establishment of shrubs on the shoreline.
- The construction of an underwater dirt bench protected by green gabions or large rip-rap which would reclaim some of the land lost to erosion.
- The planting of aquatic vegetation, protected by coir logs, in the dirt bench.
- In this way erosion is controlled, the water is cleaned and wildlife finds a habitat. The best and the cheapest solution!
LAKE VICTORIA NORTH SHORE LINE EROSION CONTROL & FISHING ACCESS
Construction of the Foundation of a Fishing Crib