08/23/1990 CONSERVATION COMMISSION Minutes

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Conservation Commission August 2 , 1990 Page 2. Mr. Humphries stated there are five resource areas included on the properties t some degree. The comumon resource area on each property is the coastal beach, coastal dune, coastal bank and land subject to coastal storm flowage up to elevation 12 on the Nantucket Sound side and elevation 11 on the Deal's Pond side. The only other resource, which only applies to one lot, is the barrier beach on lot 1379 in an area where nothing is proposed at this time. They have found with regards to Lots 1378 and 1377 that there is a role being played geologically by windblown sands moving landward from the coastal dine and providing veneer of sand over the coastal bank. The main origin of the geology in the Popponesset Bluff area is sandy loam, pitted plain deposits, found in exploratory work in relation to the septic systems. The sensitivity of the area along the Nantucket sound side must be addressed. On the Dean's Pond facing side, the loo year flood comes up to and intersects a slope above which there is an obvious break that varies somewhere between elevation 12 at the northern part of the site up to approximately elevation 22 at the southern end. Primarily, the activities proposed in the Notice of Intent will include two driveways, a cobblestone egress ramp and a retaining. wall, only located in two of the resource meas, on the coastal bank and land subject to coastal storm flowage. Elevations for the loo year storm were clarified: elevation 12 on the Nantucket sound side and. elevation 11 on the Dean's pond side. The elevation variance from 12 to 22 is the top of 'bank. Performance standards looked at are confined to 10.30 . The 8ther- p - formance standard on a coastal bank refers to wildlife habitat and this is not shown on the habitat map. Therefore, performance standards and 7 are ghat they looked at. A letter will be provided that addresses the performance standards. Activities to be discussed tonight include removal of portions of the coastal bank, filling of a coastal bank and grading and raking. Primary concern for ensuring stability of the coastal bank relates to the construction process, the sequencing of how that material is either removed, filled, graded or raped on that coastal bank. Measures have been taken in this proposal to address drainage and to get it into the ground as quickly as possible and not to have adverse effects on the stability of the bank. Mr. Sherman pointed out that under the regulations for the Town bylaw there i's a Presumption of Significance for wildlife habitat that may have to be addressed for the coastal bank. Mr. Abrahamson advised they are trying to set up a limit of site development;- terraces, flowers, nothing can legally go forward of that lime. Pacing -Nantucket sound, they would like to maintain the open lawn duality. They came up wi