This property owners were having their bank being gnawed back several feet per year, undercutting trees and becoming an eventual threat to the property’s swimming pool. The embankment also had invasive mimosa trees that were becoming too dominant on the shoreline. The 3’ high embankment could have supported a stone revetment, but with healthy marsh grass seaward of the embankment, the owner did not want to eventually drown and kill off the marsh grass as erosion continued seaward at the marsh peat level.
The Client had pursued the project in annual phases in a budgeted process.
2’ Reefs were placed just offshore of Mean Low Water. This larger reef size was used due to long fetch to the NW and to the high tidal fluctuations in the upper reaches of the North River and Mobjack Bay.
Their interlocked pattern will also trap any soils stirred up by wave action and deposited in the low energy zone behind and between the reefs.
One of the interesting results after the Phase 1 in the Spring of 2016 reef install prior to the Phase 2 shore work was that the sparse grasses (see second photo from the top) received enough protection from the reefs to begin prospering in the fall of 2016, just 4 months later (see above two pictures.
Phase 2 of the project in the Spring of 2017 was to remove the dead, dying, and invasive trees from the embankment.
Sand was added above Mean High Water. A grid system was embedded and anchored to hold the sand at a 4:1 slope. A biodegradable matting was placed over the grid cells to help hold the sand in on the greater than 10:1 slope. The elevations were than planted with the appropriate Spartina marsh grasses.