VCSA LAKE BANK RESTORATION PILOT 10-24-17 Report
The Lake Bank Restoration Pilot (approved at the May 2, 2017 VCSA Board of Directors meeting) was conducted during the last weeks of May at 3780 Saybrook Place. The purpose of the pilot was to evaluate the compacted aggregate / littoral solution for gradual lake slope drop-offs, with escarpments exceeding SFWMD criteria of 9 10. This condition is characteristic of the majority of the roughly two-mile Vanderbilt Lake shoreline.
The lake bank was restored to a 4:1 slope from the existing 16 escarpment to 2 feet below the normal low water line as permitted using compacted aggregate fill. Stone of varying size was embedded in the lake bed, at a point 2 feet below waterline, to provide a toe hold to prevent fill from receding into the lake. Drainage lines were routed from gutter downspouts into the lake below the water line. The finished slope was covered with Turf Reinforcement Mat, and secured with J rebar hooks and 6 staples.
When installation was complete, the dry season was still in place. The historically low lake level and lack of rain prevented planting of littorals. Later in June, 15 of rain fell in three days. The lake overfilled its banks and remained high through the ensuing 2017 summer rainy season. Littorals will be planted as the water level recedes exposing more bank.
Several outstanding issues will need further evaluation and resolution before the pilot is considered an unqualified success. One issue encountered was the Turf Reinforcement Mat floating to the surface due to the rapid rise in lake level. The contractor will come back and reattach the mat with J hooks or equivalent that provide greater gripping power to the compacted aggregate. Also, evaluation of littorals will be made over the course of the dry season as progressive plantings are completed. Despite the lack of littoral plantings, there is no visible erosion. This condition will be monitored during the dry season as the water level recedes and more of the restored slope becomes visible.
Photos (23) of the restoration pilot are attached. They show the various stages of the Pilot Bank Restoration Project as presented at the VCSA BOD 10-24-17 meeting.
Completed 4:1 Slope Viewed From Commons Area and Essex Place: 2 photos
Original 16 Shoreline Escarpment: 2 photos
Staging in Saybrook Cul de Sac: 2 photos
Access Through Pilot Property Front Yard and Sideyard Utility Right of Way: 3 photos
Drainage Lines From All Three Lake Facing Gutter Downspouts : 1 photo showing method
4:1 Slope Restoration Starting at Existing Escarpment: 6 photos
Turf Reinforcement Mat & Sod Installation: 7 photos including access path resod