ISLAND RECONSTRUCTION Sample Clauses

ISLAND RECONSTRUCTION. The Reach MM Island will be re-established on top of the cap by the addition of various materials including graded cobbles; similar to other island areas present in the Tittabawassee River. The purpose of the re-constructed island is to promote natural restoration of a stable island habitat that would remain an island during typical water flow conditions and provide structure for natural vegetation. The re-constructed island will be constructed over the in-situ containment cap using suitable sand fill. The top surface of the fill material will be stabilized with geoweb and the outer edges of the island fill will be armored with cobbles. Cobbles will also be placed on top of the island fill to provide structure and to promote sediment accretion. Natural perennial aquatic species will be planted as plugs on the island and annual species would be allowed to colonize. A schematic cross section of the re-constructed island is shown on Figure 3 and a plan view schematic of the re-constructed island is shown on Figure 4. The fill material will consist of poorly sorted silty sand. The fill material will be obtained from a suitable source. In order to encourage revegetation, total organic carbon (TOC) levels in the added material will be similar to levels observed in other island areas of the river (i.e., 2% as seen at the island in Reach N). Organic material may be added to the silty sand prior to placement in order to obtain the desired TOC level. The armor stone will consist of a rounded or sub-angular cobble with a diameter generally between 3 and 12 inches. The average diameter will be between 4 and 8 inches. The cobbles will be placed around the perimeter of the island to a thickness that armors the sides of the island. The interstitial space between the perimeter cobbles will be filled with the silty sand fill. The same cobble material will be placed on top of the island, covering 30 to 50 percent of the island surface. The topography of the Island will be varied, mimicking naturally occurring micro-scale topographical variation. The geoweb will be placed on top of the fill prior to placement of the cobbles. The lower approximate three quarters of the geoweb will be filled with the silty sand fill and the cobbles will be placed in and on the geoweb. Silty sand fill will then be added on top of the cobbles to fill in the remaining space in the geoweb. The geoweb will be a minimum of 6- inches thick and will have 12-inch diameter cells (GW-30V-6-08-29). Grasse...