HomeMy WebLinkAbout2017_02_27 Coastal Zone Management Commission Minutes Town of Mamaroneck — Village of Larchmont
COASTAL ZONE MANAGEMENT COMMISSION
TOWN CENTER:740 West Boston Post Road,Mamaroneck,NY 10543-3353
;r... - = TEL:914-381-7845 FAX:914-381-8473 conservationdept@townofmamaroneck.org
CZMC Minutes-Approved
February 27, 2017
A meeting of the Coastal Zone Management Commission (CZMC) was held on Monday,
February 27, 2017 in the Mamaroneck Town Center, Conference Room D, 1st Floor, 740 W.
Boston Post Road, Mamaroneck, New York. The meeting was called to order at 7:30 p.m.
MEMBERS PRESENT:
Marc Godick, Co-Chair
C. Alan Mason, Co-Chair
Tara Anderson
Howard McMichael
REGRETS:
Matthew Teitsch
OTHERS PRESENT:
Elizabeth Paul, Environmental Planner, Town of Mamaroneck
Abby Katz, Liaison, Mamaroneck Town Board
Robert Fletcher, Candidate for CZMC
Jonathan Avellino, Applicant, 5 Valley Stream Road
William Lachenauer, Hudson Engineering & Consulting, 5 Valley Stream Road
Anthony Gioffre, Attorney, 5 Valley Stream Road
1. Approval of Minutes
The minutes of the October 24, 2016, November 28, 2016 and January 23, 2017 meetings
were approved as submitted.
2. Referral—5 Valley Stream Road—Wetlands and Watercourses Permit—Referred
by the Town of Mamaroneck Planning Board
Jonathan Avellino, William Lachenauer and Anthony Gioffre presented the proposal for
the reconstruction of the single family home at 5 Valley Stream Road, within the
wetlands buffer zone of the Sheldrake River. As proposed, stormwater runoff from the
property will be collected and pumped to a bank of 12 infiltrators located in the front/side
yard with an overflow to the catch basin on Valley Stream Road. According to the
drainage analysis, the test pits and percolation tests were conducted several years ago
during a period of dry-weather and groundwater was observed at 52" and 72". The
basement slab and trench drain as proposed will be located below the water table,
requiring constant pumping of water to the infiltrators, surcharging the system before
stormwater is introduced. During a 25-year storm event this condition will be
exacerbated and during a 100-year storm, the property will be under flood waters.
Page 1 of 3
CZMC found the proposal to be significantly inconsistent with policies 11 and 17 of the
LWRP which state:
Policy 11:Buildings and other structures will be sited in the coastal area so as to
minimize damage to property and the endangering of human lives caused by flooding
and erosion.
Policy 17: Whenever possible, use non-structural measures to minimize damage to
natural resources and property from flooding and erosion. Such measures shall include:
(1) the setback of buildings and structures: (2) the planting of vegetation and the
installation of sand fencing and drainage systems; (3) the reshaping of bluffs; (4) the
flood proofing of buildings or their elevation above base flood level.
Based upon the site and surrounding area being in a flood prone area, CZMC makes the
following recommendations to ensure consistency with the LWRP:
• The percolation test data should be reevaluated and certified by the applicant's
engineer to determine/confirm the seasonal high water table at the site.
• Based upon the existing percolation test data, the basement slab and driveway trench
drain elevations should be raised a minimum of 2 feet to avoid the slab and drain
bottoms potentially being below the water table, which would avoid the need to pump
groundwater into the stormwater infiltrators during dry weather conditions.
Furthermore, if further review of the percolation test data indicates that the seasonal
high water table is higher than what was assumed, the design should be modified
further to ensure that the bottoms of the basement slab and trench drain are above the
seasonal high water table.
• The applicant should give consideration to waterproof the basement with a structural
membrane type waterproofing system and not rely on pumping of water from one or
more sumps in the basement during seasonal high water conditions and/or severe
storm events.
• Roof drains from other portions of the site are proposed to be pumped to the
stormwater infiltrators. Strong consideration should be given to reconfigure the
alignment and elevations of the drainage piping to avoid the need for pumping.
3. LWRP Update
Elizabeth Paul sent CZMC members a complete draft of the LWRP. Comments were
submitted today by several members and will be incorporated into the next draft. A letter
will be written to Justin Datino asking Larchmont for additional information where
needed. Marc Godick and Elizabeth Paul will set up a conference call for Friday
afternoon to work on the document.
Page 2 of 3
4. Old Business
Robert Fletcher was introduced as a potential CZMC appointment by the Village of
Larchmont. The Town recently received a resume from a resident who is interested in
volunteering. Councilwoman, Abby Katz will be in touch with her.
5. New Business
No New Business to discuss
The meeting was adjourned at 8:45 p.m.
Page 3 of 3