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HomeMy WebLinkAbout1987_08_20 Conservation Advisory Commission Minutes 0111 12 A Q ti% .0 RECEIVED ' OCT 19 1987 Town of Mamaroneck PATRICIA A.DICI000I0 4/7 Conservation Advisory Commission �' MAMARONECK N.Y. ,IS Area Code 914 740 West Boston Post Road Mamaroneck, N. Y. 10543 *t)9139:41 MINUTES 381-6133 A special meeting of the Conservation Advisory Commission (CAC) was held on Thursday, August 20, 1987, at the Town Center, 740 West Boston Post Road, Mamaroneck, New York, to comment on the Gardens Lake Dredging Project. The meeting commenced at 8:05 P.M. Members present: Robert Komitor, Chairman Gloria Allen Charles Bernstein Suzanne Carpenter Mary Anne Johnson, Emeritus Others present: Dolores Battalia, Town Supervisor Bonnie Burdick, Larchmont Reservoir Committee © Robert Hohberg, Water Monitoring Consultant Tom Leddy, Beautification Director C. Alan Mason, Coastal Zone Management Commssn Claudia Ng, Environmental Coordinator Ortwin Meyer, Consultant Engineer Howard Sloane, Friends of Hommocks Salt Marsh St. Clair Richard, Soundview News Maria Mora, Recording Secretary This was a special CAC meeting to discuss the alternatives on the dredging of Gardens Lake. It was reported that Mr. Altieri had planned to be present at this meeting to address the Commission of certain aspects of the proposal but was unable to attend. So, Ms. Ng explained the background of the proposal, summerizing what was said in the engineering report and at the last meeting. Ms. Ng related the fact that at this stage the Town Council would like CAC's opinion on the Gardens Lake dredging project. She stated that the engineering firm has recommended dragline dredging. This alternative proposes to dredge approximately 6,000 cubic yards (c.y. ) of sediment out of Gardens Lake by means of 12 1/2 c.y. trucks and bringing it down to the Hommocks Salt Marsh. This dredge will then be placed in trenches in an egg carton fashion. Ms. Ng also reported that she, the Adminisitrator and two engineers from Malcolm Pirnie, Inc. , had gone to New York State Department of Environmental Conservation (DEC) up in New Paltz last Tuesday to find out what their opinion was on this matter, but they did not give many helpful comments at © this time. She said that they would probably have to review the project under the Water Quality Laws of Article 25 of the Conservation Law. Ms. Ng remarked that although Gardens Lake is not classified under the State CAC minutes - 8/20/87 ® Freshwater Wetlands Law, DEC may still have to review this project under its Freshwater Wetlands regulations because the Town is not allowed to review its own projects under the Local Freshwater Wetlands Law. It is presently being discussed whether DEC will take that responsibility. Ms. Ng commented that Malcolm Pirnie feels that he will not have any problems submitting a DEIS because much of the necessary information would have already been obtained for all the engineering reports to the Town. Ms. Ng noted that CZMC has asked Malcolm Pirnie to address the possibility of lateral dispersement if the dredge spoils are disposed of at the Hommocks and to consider other disposal alternatives. CZMC is concerned that subsurface layers of the Hommocks athletic field may be squooshed out into the adjacent marsh if more material is placed on top. Mueser Rutledge, Inc. , a special consulting firm in N.Y.C. , has the opinion that if the sea wall hasn't moved, then there is no evidence of such lateral dispersion. In Mr. Leddy's opinion, the sea wall has not moved. Another alternative that CZMC wanted Malcolm Pirnie to look into was the possibility of dewatering the lake. This alternative proposes letting the lake dry out and then sending the material out to a landfill for use as fill or capping material. Ms. Ng reported that Mr. Trachtman believes that the material could dry out in 6 weeks under ideal conditions. The weather would have to stay dry and that the water table would have to be low enough to prevent ground water seepage. Also, additional studies will have to be made to determine if the material is acceptable for landfill covering. CAC recognized the difficulty with the dewatering alternative since the weather cannot be controlled. ® Mr. Komitor asked Ms. Ng if CZMC had suggested any other alternatives. Ms. Ng reported that CZMC is very much against the dumping of the dredge spoils at the Hommocks field because it is adjacent to a designated Critical Environmental Area (CEA). Mrs. Allen questioned the quality of the dredge material, to which Ms. Ng replied that the material is not good soil nor was it determined to be suitable for fill. Dr. Mason noted that it would not be wise to dig up the Hommocks after so much was done just to get grass to grow there. Dr. Mason commented that the adjacent CEA was not his main concern. Mr. Komitor questioned how much of the field will be dug up and Ms. Ng responded 630 feet. Dr. Mason commented that the trucks would not likely be confined to one area and would thereby make the Hommocks Marsh look like a construction site. Impact on the field as a result of the construction should be reviewed. Complaints of nearby neighbors because of soil damage to their property may result from this dredging project. Dr. Mason gave his opinion that the dredging project is feasible, but would not be quickly or neatly done. Mr. Komitor asked how far down into the ground would the lateral displacement be. Mr. Meyer said that it is very difficult to give an exact answer because of the uneveness of the sediment. There were questions if this area was being used for anything. Mrs. Johnson responded that it is used in the wintertime with classes. Another question was whether this material after being compressed would eventually lift up and release itself. No supression test has been made because there is no definite way of doing one. Mr. Komitor asked how many egg shell compartments will be needed to © complete the whole job and the answer was 700. Mr. Komitor wanted to know if CZMC had discussed any other alternatives. Ms. Ng mentioned that barging had been considered, but the Army Corps of Engineers will not allow sediments from unnavigable waterways to be dumped into navigable waters. -2- CAC minutes - 8/20/87 Dumping it into a marsh was suggested but a special permit is required for this type of procedure. Ms. Ng informed the Commission that DEC will review the report and give their opinion on the possibility of any toxic problem with the heavy metals present. It was mentioned that the tests involving heavy metals are costly and slow. Mrs. Battalia stated that you can't dump within 12 miles of the coast. Mr. Komitor suggested investigating the full cost of barging beyond 12 miles. Dr. Mason noted that this is being looked into and should be on next meeting's agenda for discussion. The idea of piping the spoils to the Rockland-Thruway pocket/conservation area was raised. Some objected at the use of this area because it is in the flood plain. However, Mr. Meyer expressed that he thought this among the better ideas and should be analyzed more thoroughly. Mr. Komitor suggested having some kind of containment or rip-rapping in the Hommocks site. Mr. Leddy noted that there will be rip-rapping but with plastic because it is cheaper, both money and material wise. Mrs. Allen questioned whether the plastic would allow the water to filter correctly, but Mr. Leddy responded that it would be a special plastic designed specifically for such purposes. Mrs. Johnson felt that this proposal will contribute to a maintenance problem. Mr. Meyer and Mrs. Johnson believed that any material dumped into the Hommocks area will continue to decompose for at least 10 years. Mr. Komitor suggested keeping tabs on the settling and proposing maintenance to prevent any sinking. Mr. Komitor concluded that Malcolm Pirnie should consider extra lining provisions for the Hommocks and the prevention of lateral dispersement. ® Mr. Komitor asked if CAC had any other ideas. Mr. Meyer stated that he liked the Rockland Avenue alternative, but Ms. Ng noted that it would be very difficult to work at because it is a steep site and near a thruway. Mr. Leddy commented that you would not be able to remove the material once it is in place. Mr. Komitor stated that this alternative would be cleaner and make transporting material easier. Comments were made regarding the potential impacts to fish and wildlife in the area. Ms. Ng reported that Paul Degenhart had hoped for someone to be out there to collect all the fish for transplanting to the Reservoir. Dr. Mason suggested placing the material on cars down at the railroad substation, but Mr. Leddy commented that it has to be dewatered. Dr. Mason and Mr. Komitor suggested dewatering it in wooden tanks at Rockland Avenue and then transporting it to the railroad site to be sent out by railroad. Dr. Mason stated that this would be cheaper than barging. The main question from all CAC members was where would the material go. It was reported that Mr. Altieri had written a letter to DEC requesting a list of the various sites that a dredge spoils could be dumped at. Mrs. Battalia asked Ms. Ng if the list had arrived yet, to which Ms. Ng replied that it had not. Mr. Komitor questioned how many cars would have to be rented. Dr. Mason commented that it is around $2.75 per day to rent a railroad car. It was suggested that the cost of the cars and the destination possibilities be investigated. The question of where the spoils could be dewatered was asked. It was suggested that the old Con Edison station, which is alongside the river, be used. It was recommended that additional test be done to determine what is exactly in the material because people will not want it unless they know. O Mrs. Battalia informed CAC that those test are being made at the present time. Mrs. Allen brought up the question of what if it were toxic material. Mr. Komitor stated that if it were toxic, he would want to know why and where it came from. -3- ' CAC minutes - 8/20/87 C Mr. Komitor asked if there were any other comments or suggestions at this point. Mrs. Battalia requested the CAC to give their opinion as to whether Gardens Lake should be dredged in the first place. The second issue that she thought CAC should address in the near future is the growing problem of litter dumping. Mr. Komitor questioned if CZMC had any objection against the dredging of Gardens Lake. Ms. Ng replied that their only concern is the disposal of the spoils. After some discussion, it was confirmed that Gardens Lake should be dredged. However, it was suggested that a permanent area for all our future dumping should be located. Mrs. Battalia said that she would like to have the Commission's opinion for the Board by September. Mr. Komitor asked when would be the best time for this project to be done. Dr. Mason recommended that it get started as soon as possible, perhaps by April. Mr. Sloane expressed his negative opinion on the dredge spoils being dumped on the Hommocks Field. He felt that the fields were now just beginning to be useable as playing fields and that the sea wall was not completely intact. Mrs. Battalia also requested that in the near future CAC should examine where the Town's woodchips should be placed. Mr. Komitor agreed and said that this issue will be addressed at the next meeting. It was mentioned that, eventually, the Village of Mamaroneck will have to get involved with this problem since they are downstream of Gardens Lake. All members received a copy of the preliminary engineering report. Mr. Meyer mentioned that he could not find the total calculations for this project in the report. Ms. Ng stated that on page 9 there is a table listing the costs for dredging portion only. Mrs. Battalia commented that the figures Mr. CMeyer wants could be found in the engineer's proposal. Mr. Komitor requested Dr. Mason to follow up on his idea of using railroad cars. Dr. Mason will first find out if this alternative will work and then inform CAC. Mr. Komitor suggested working with CZMC on this project because it is difficult one. Mrs. Johnson suggested that we think about the possibility of vandalism during this project. It was asked if the pipes for hydraulically pumping the sediment downstream were flexible. Mr. Meyer replied that it could 30 to 40 mechanical joints. Ms. Ng requested that CAC's opinion be written by the 9th of September. There being no further business, the meeting was adjourned at 9:50 P.M. -4- i