3/7/1991 CONSERVATION COMMISSION Minutes

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,1 Conservation Cossion March 7. 1991 Page 4. . McGrath advised there is one foot of space between the stringers and existing surface. The stairway is elevated above the existing beach grass at the base of the bank. All work will be done by hand. ir. Hoeyer asked how they will prevent the slope at the top from eroding and what will be put under the stairs? The stairs will have water running through and channeling behind. khat will be used to prevent erosion? Mr. McGrath stated it is heavily vegetated with indigenous species. They will use a fiberglass surface on the stairs to provide light. Mr. Sherman suggested bringing in the arborist/consultant for the $25.00 fee, Mr. McGrath agreed, Mr. Home er asked if the riprap would be double thickness? Hr. McGrath stated it may be, when he gets into it. Mr. Homeyer was concerned with undermining of the toe stones and loss of the gall. Mr. McGrath felt it would be better to have one big stone than two, The reason most- f these fail. has more to do with the effect of soil. moisture and the effect of piping because soil. particles behind the wall have washed out through the crushed stave used for chinking. He does not know of any walls that have failed when filter cloth has been used. Mr. Homeyer pointed out that the elevation is 23, 19 from the beach, and they do not show the armoring going up that high. Mr., McGrath stated it is the same elevation as the ones on either side, Mr. Coffey advised the length of the walkway at the base was puzzling and was told they extended it all the way across to preserve the beach grass. Mr. York asked how they would access the beach with heavy equipment? They will enter through New Seabury land at 'fide match. Mr. trot ke advised a portion of the structure is on New Seabury property. They have no problem with the armoring but are concerned with the impact on the beach. It was an eroding bank and was out further. It has contributed to the sediment on the beach. New Seabury would prefer to see beach nourishment mandated as a condition for construction of the seawall.. There has been sig- nificant recession of the beach and it will eventually disappear or be very mun:mal. Mr. Coffey asked if abutters on both sides are contributing to beach nourishment? Mr. Grotzke advised some of the recent walls are; those prior to 1983 have not been nourishing. and those built with an inappropriate vertical face or rough- ness have considerable. erosion in front of their seawalls due to wage refraction or run- . Mr. Coffey asked if the client has considered beach nourishment? Jeremy Carter, representing the client, advised it is his client's position that his property has accumnulated more sand than his abutters. He is not interested in doing an open-ended beach nourishment plan.