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HomeMy WebLinkAbout1984_10_25 Conservation Advisory Commission Minutes corrected 4 r /101 It %I TOWN OF MAMARONECK CONSERVATION ADVISORY COMMISSION DO,? 29 l,�gA tf`^ AND WATER CONTROL COMMISSION JOINT MEETING AJ44 nv.; . c11 .0 N.y � A regular meeting of the Town of Mamaroneck Conservation Advisory Commission and the Water Control Commission was held on Thursday, October 25, 1984, at the Weaver Street Firehouse. The meeting commenced at 8:05 P.M. Members present: Dr. C. Alan Mason, Chairman, CAC & WCC Mary Anne Johnson, Emeritus Ellie Fredston, CAC & WCC James Santos, CAC Robert Hohberg, CAC & WCC Also present: Cliff Emanuelson, Conservation Consultant Thomas Amlicke, Town Councilman Jane Moss, L.I.F.E. Center Buddy Atherton, Liquiflo, Inc. Elizabeth Imperato, Recording Secretary Administrative matters: The minutes for the September 20, 1984 meeting were discussed and approved. The next meeting for the Conservation Advisory Commission and the Water Control Commission is scheduled for Thursday, November 15, 1984,at 8:00 P.M. , at the Weaver Street Firehouse. r Environment: Coastal Zone Committee: Dr. Mason reported the preliminary draft was sent to Albany; a public hearing is scheduled for November 8, 1984. Cherry Lawn Parcel: Dr. Mason stated trees have been cut down along Weaver Street; a shopping and parking lot will be built. The Commission has received no notification on this project; Dr. Mason will contact Mr. Altieri for information on this action. Mrs. Johnson reported the hydrological study being compiled by Laura Tessier is not in its final form; Ms. Tessier will notify us when completed. (2) Water Courses and Water Bodies: Reservoir Preservation (lower dam) : Dr. Mason reported the dam leakage • is increasing and evidence of erosion is more evident at the south-west corner of the lower Reservoir. A meeting is scheduled for this Saturday with engineers and Jim Johnson. Mr. Emanuelson stated the lower dam needs immediate attention- refit the stones and lower the water level at the spillway. Contamination of Storm Water Drains: Dr. Mason reported that at a meeting of the dedication of the Reservoir, Mr. Kellogg requested Bob Hohberg to run tests from the Maple Hill area, under the Thruway, out the northwest corner of the Rail-road parking area. Mr. Hohberg took samples which indicated we have very high ecoli and fecal counts; there is raw sewage in quantity in the stream. A follow up investigation is underway. Possible construction in Rye: Dr. Mason reported on plans for a large 585 parking space area in Rye; it was defeated by the Rye Planning Board. Automation of Reservoir Valve: Mr. Altieri and Ms. Battalia requested the Commission for specific recommendations; Dr. Mason will furnish this information at the next meeting. Fram industries: A presentation was made by Buddy Atherton, Sales Engineer from Liquiflo Inc. Fram specializes in oily water separating devices; suggested use of this system is the Pinebrook chamber which is a common point. Cost is estimated at three quarters to one million dollars. Mr. Atherton also suggested a sensing device with a monitor for use with this system. Dr. Mason thanked Mr. Atherton for his presentation; this idea will be discussed further by the Commission. j (3) Communications to Commission: Dr. Mason and Mr. Emanuelson met with Ellen Muller from NYS DEC and discussed funding requests for L.I.F.E. Center. Proposals were rewritten and presently read Air Quality and Water Quality. They were passed on by Ms. Muller who recommended apgroval. Federated Conservationists: Mrs. Johnson will ask Russ Keller about the Oil Spill Compensation Fund and will advise the Commission further. Budget: A discussion was held on the budget and was passed by the Commission. A question was raised as to the $8,500 for Flint Park Field Development. Bayberry: Mr. Santos has tried unsuccessfully to contact Bayberry Association; Mrs. Fredston will furnish Mr. Santos with the name and number to contact. New or other business: Beringer Property: Dr. Mason reported the Planning Board has agreed to go with a full E.I.A. - type I. (See attached memorandum) . I. Storm water meeting: Dr. Mason made a presentation at the meeting sponsored by Diane Keane. Dr. Mason discussed development of the property adjacent to East Creek where Firestone will buy the property (including IHOP) and put in a 10 bay facility; discussion centered around traffic study conditions and effects on East Creek. Discussion was also held on the Palmer Avenue Honda Agency Project which was presented to the Town Planning Board. The Village of Larchmont has (4) y expressed consern; Dr. Mason was asked by the Commission to write to the • Town Planning Board and Village Planning Board regarding drainage and traffic concerns of the Commission on this and the preceeding project. There being no further business to discuss, the meeting was adjourned. Dated: October 25, 1984 • 4 MEMORANDUM Date : October 9 , 1984 To : Town of Mamaroneck Planning Board From : Town of Mamaroneck Conservation Advisory Commission Town of Mamaroneck Freshwater Wetlands Commission C .A . Mason , Chairman Re : Environmental Impact Statement on the Proposed Development of the Berrenger Property During the last several weeks members of this commission as well as the paid consultant to the commission have examined the available maps of the proposed ' development area. Generally speaking, the maps were not very helpful. We then visited the property and tried to correlate the maps with the actual terrain. Our conclusions are that the development of this property must be planned very carefully as the potential for serious negative impact on the environment is extremely high. t Flood Impact This property is composed of slightly more than 30 acres of irregular land through which passes a small stream which, after exiting the property, joins the East Branch of the Sheldrake River. Within the property itself there are three areas of erosion which indicate runoff during periods of rain. These three areas of runoff, which are actually small streams themselves, join the larger stream within the property and contribute their water to the larger stream which later joins the East Branch of Sheldrake River. It should be noted that the East Branch of the Sheldrake River is the same stream which later flows into the conservation area north of Rockland Avenue, under Rockland Avenue, through the Badger Camp Property and down along Valley Stream Road where it joins the-West Branch of the Sheldrake River at the intersection of Valley Stream Road and Brookside Drive (East and West) . ( 1 ) This, area at the confluence of the two branches, is a severe flood area which N has been inundatet numerous times in the last 40 years. The three small streams within the Berrenger Property, whose flow is not constant, are irregular and wandering thus serving to delay the runoff from the property. This delay is further enhanced by the natural spongy condition of the undisturbed soil found in undeveloped woods. The large number of mature, wide- leafed trees found on the property further help to lessen the runoff by retention of water in their root systems and transpiration of water vapor into the air. 1 Thus the contribution of water to the Sheldrake River from this property is delayed and has less of an impact on downstream flood-prone areas than can be anticipated when the property is developed and roads and driveways are constructed and paved, and some, or all, of the large trees are removed. The logical solution to the problem is to provide detention facilities within the property to delay the flow of storm water that falls on the property to the extent that there is no increase, actually there should be at least a 10% decrease, in the rate of runoff into the stream that flows through the property. There is not likely to be an argument over the need to provide detention facilities. The argument is more likely to center on the capacity to be created. • During the past decade the standard has been the so-called ten-year storm. This is proving to be an inadequate measure of detention facility volume. We have r had, during the past 14 years, one 35 year storm, at least one 17 year storm, one 14 year storm and numerous 1, 5 and 7 year storms. As the development of the area has .progressed the impact of theses storms has increased with no parallel adjustment in the detention facilities required. It is the opinion of this commission that a more direct and easily understood • standard must be developed and applied. We feel that an appropriate standard for this area is that a property proposed to be developed be able to retain, within its boundaries, the rainfall impacting on that property resulting from 12 inches of rain falling over a 72 hour period, and that the water thus detained be released in as nearly uniform rate as possible over an additional 72 hours. 1 Transpiration of water vapor through the surface of the leaves of • broad-leafed tree can be as much as twenty tons of water a day during favorable conditions of temperature and sunlight . ( 2 ) At first glance, this might appear to require that 30 acre-feet of detention be provided on the property in question. This is not the case. For purposes of planning, it would be reasonable to assume a uniform rate of rain for the first 72 hour period. During that period approximate half of that water would be permitted to exit the property as the 3 days of rain 2 would coincide with the first 3 days of the 6 day discharge period. The net result would be that at the end of the 3 day rain period the water detained on site would be at it greatest but would amount to only about half the total rainfall impacting the property, as half would already have beert discharged. This 15 acre-feet of detention could be in the form of recreation area or open space surrounded by a suitable embankment. A five-acre ball field or park area need only have a three-foot high, gradually inclined embankment around it to serve as a detention area in time of flood. At other times it would be dry. It has been common practice in the past for the Town of Mamaroneck to accept money in lieu of land for recreation. It is our opinion that this would be an appropriate time to insist on dedication of a suitable piece or pieces of land for recreational purposes and that it be situated and contoured to aid in flood water detention and control. It should also be noted that there is, at the present time, a serious flooding problem adjacent to the northerly end of the proposed development area at the point where the stream which parallels the end of Kolbert Drive enters the t property. This stream is unable to handle the present flow from the Murdock Woods development area south of Griffin Avenue. When the necessary detention facility is created within the proposed development, every effort should be made to at least maintain the present capacity of the stream as it passes through the property. The detention ponds must be adjacent to the present stream but the flow of the stream should not be routed through the detention facilities. The preliminary map made available by the developer indicates that roads and homes are to be developed immediately adjacent to or on top of the present stream. In our opinion, this is inappropriate. 2 Three days of rainy weather is common when a northeasterly storm hits this area . The rain usually builds slowly in intensity for the first one and one-half to two days , and tapers off during the third day . Flooding is usually encountered during the last day and one-half. ( 3 ) The philosophy behind this recommendation is that a developer should not be saddled with the task of solving the problems created by past planning mistakes, but should not, on the other hand, be permitted to add to a problem, even to the smallest extent. No single prior development can be credited with causing the entire flooding problem, but each project has contributed a little bit, with the result that several areas of the town are virtually inundated on a regular basis. Sewage Impact It is presently necessary to pump sewage from the homes at the lower end of Kolbert Drive, which are at a higher elevation than much of the proposed development, to a gravity main located at a higher elevation. It is not clear from the map provided by the developer if it will be possible to construct a gravity sewer line from the proposed development area. If so, we would recommend that it be made large enough to accommodate the effluent from Kolbert Drive so that the present pumping station can be eliminated. If it will not be possible to construct a gravity system, careful consideration should be given to the adequacy of the pumping station. The one located at the end of Kolbert Drive appears to be operating at close to its maximum capacity. Consideration must also be given to the ability of the Harbor Island treatment plant's ability to handle the increased load of thirty or more additional large homes. This plant frequently must bypass sewage during periods of high volume discharge. r Traffic Impact Questions have been raised as to the need or advisability of opening a second access road into Murdock Woods. This matter should be referred to the Traffic Commission for consideration. It is not the purpose of this commission to involve itself in that decision except to note that there are valid safety considerations which can be considered in support of both positions. The additional traffic generated by thirty homes would not seem to have a major impact on the Fenimore Road. Thank you for permitting us to be of service. • ( 4 ) TOWN OF MAMARONECK WESTCHESTER COUNTY. N. Y. FOUNDED 1651 TOWN OFFICES 740 WEST BOSTON POST ROAD w MAMARONECK. N. Y. 10943 OFFICE OF THE 03 (914) 698-3441 Vf N ADMINISTRATOR (914) 698-5085 August 9, 1984 Dr. Alan C. Mason 482 Weaver Street Larchmont, New York 10538 Dear Alan: I would like to communicate to you the information the Town received at a meeting with representatives from the State Department of Transportation concerning the Hutchinson River Parkway project. The meeting was held in the Village of Scarsdale and included the chief elected and appointed of- ficials of the Town of Mamaroneck, Village of Mamaroneck and Village of Scarsdale. In attendance from the Department of Transportation was the Regional Director, Albert Dickson and Nicholas Pucino, the Co-ordinator for the Westchester Parkway Group. The purpose of the meeting was to dis- cuss the impact of drainage on the three aforementioned municipalities resulting from the reconstruction of the Hutchinson River Parkway. lare According to the Department of Transportation, the Hutchinson River Parkway project will have an insignificant impact on the Sheldrake River basin. Again, according to the Department of Transportation, they have estimated that the increase of run-off will be less than one tenth of one percent due to the fact that there will not be a significant increase in the paved areal - of the Hutchinson River Parkway between Wilmot Road and Mamaroneck Avenue. - The increase in paved area will result from the installation of paved shoulders in both directions. With respect to the flooding in the Pinebrook area, the State will be constructing a small berm along the Pinebrook in an attempt to reduce the flooding problem to the homes on Pinebrook Boulevard. Drainage on the east branch of the Sheldrake River will be addressed by re- placing two small culverts at Quaker Ridge Golf Club with a twenty-four inch culvert. - `—' At this meeting, we stated to Mr. Pucino that siltation in the Town is a significant problem and inquired as to what would be done to control silta- tion during construction of the Hutchinson River Parkway. Mr. P8cino stated _ that the Department of Transportation reimburses the contractor separately for hiring appropriate staff to monitor siltation during the construction. The staff hired to monitor siltation is responsible for reporting to the . CO Dr. Alan C. Mason -2- 8/9/84 Department of Transportation on a regular basis. Additionally, as land is cleared, hay will be spread to help prevent siltation. • There was also discussion of the ,affects of the Hutchinson River Parkway project on the Mamaroneck River basin. Due to the fact that the Hutchinson River Parkway will be increased to six lanes north of Mamaroneck Avenue, it has been determined that there is a significant affect on drainage. To re- . solve the problem, a retention basin is to be constructed north of Mamaroneck Avenue for the purpose of maintaining a stable rate of flow during a fifty year storm. We stated to the Department of Transportation officials that we would prefer to see a zero increase in run-off on the Sheldrake basin. Weade mthem aware" of the fact that while the Hutchinson River Parkway pro.fect may not alone in- crease the problem, there is a cumulative affect caused by developments in and around the Sheldrake River basin. It is anticipated that the construction will begin south of Mamaroneck Avenue in the spring of 1985. 41 I would be happy to discuss this matter with you further at your convenience. Very t ly yours, tr ,% ��_ . - Stephen V. Altieri Town Administrator SVA/ct cc: Mary Ana-T Johnson Supervisor Battalia