7/9/1992 CONSERVATION COMMISSION Minutes

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Conservation Commssion July 9, x.992 Page 2. Mr. Hayes advised they will start the Bel kin seawall in fire weeks. Six profiles will be done; they are collecting data. They will be doing to the mid-point o opponesset Spit. As the seawall is completed, they will tie into the land court plan. They will know the entire beachfront from the golf course. to id-point of opponesset Spit. The whole thing is migrating to the northwest and perhaps some of the groins are 'the reason for that. Mr. Crispin displayed an erosion chart, 1938 through 1980# 'T ey developed a 50 year erosion rate, 7 loths of a foot per year. During 1980 through 1991, there was a tremendous acceleration of erosion. The slope of the bank remained 1-1/2 to 1 until the hurricane. Mr. Sherman asked if there was a narrative re beach nourishment and was told it is in the No tice of Intent. Mr, Hayes advised they came up with l.7 for Maushop as the most rapid rate in a time period. The regional beach nourishment program is on-going for 1.8M; inform- ation is in the office. 'fir. Hayes next displayed a schematic of the design, revetment detail.. It was asked if the drift was attributed to the three storms. Mr. 'Ha - yes advised he used actual weather logs; there were twenty such storms. Mr. Crispin stated it is a double Layer revetment with filter fabric beneath the tones. Above the 100 year storm surge, they went down to one stone. There is allowance for some run-up. It is 25-30 feet to the crest of the bank. Mr. Hayes advised they are guaranteeing % success rate on plantings. Ed Baker asked the size of the holes and was told 1" x 21' rectangle. Mr. Hayes displayed a topographic site plan with the Nocera seawall shown as shaded area. It is understood a filing is forthcoming for this. An inventory f the bank showed four nesting areas of Banc Swallows. East-northeast storms would bring storm wages in. They have designed for the southeast storm. There is a path coning down to the coastal bank, They will maintain this with Armophila and the sand will accrete. There should be a walkover structure. Mr . Sheman asked wheren the narrative they addressed alternatives if the Nocer wall is not built. Mr. Hayes stated it is in the EIR and in the Not*ce• he offered to make this a supplement to the Commission. . Homeyer asked, if abutters are restricted from using the path, could they use the walkover? Mr. Hayes stated they could; he would �t this jn writing, A schematic of the construction phases was shoran. Mr.- Crispin stated they will place the crane above Mean High water on the beach. 'There will be 80 yards of sand fill. It is elevation 16 at the top, the base is 4 - 6 at the high point. Mr. Homeyer asked what would be used for matting for the beach ass? Mr. Hayes advised beach grass can belated without matting on the top and they Will use very thin Curler biodegradable to hold therm in place. It is wooden straw inside plastic mat. Mrs. Simons asked if fir., Hae would coordinate this and he stated he lar t -•� cold. They PO o start the ,fob the first of 'ebruary. Planting is in the Notice of Intent.