HomeMy WebLinkAboutSP-24-08 - Supplemental - 0870 Williston Road (6)Memo
164 Main Street, Suite 201 | Colchester, Vermont | P: (802) 878-0375 | email@krebsandlansing.com
Date: 03/26/2024
To: Marla Keene
From: Derick Read, PE
Re: DoubleTree Hotel Addition and Parking Garage – River Corridor
12.07 River Corridor
Section 12.07 of the South Burlington LDRs outlines the regulations related to protecting and wisely developing
the mapped River Corridors in the city. The Agency of Natural Resources, through the Natural Resource Atlas,
has identified a perennial stream adjacent to the DoubleTree Hotel site as shown on the site plans. As such, per
section 12.07(F)(2)(c) of the South Burlington LDR’s, a River Corridor is defined to include “all land within fifty
(50) feet horizontal distance from the top of bank or top of slope, whichever is applicable given the stream’s
fluvial geomorphology, of all other perennial rivers and streams.”
At the advice of Kyle Medash, the Western Floodplain Manager from the ANR Rivers Program, Krebs & Lansing
reached out to Chris Brunelle, as his office regulates perennial streams for the state. As part of our
correspondence Chris provided the following:
Hello Derick,
As we just talked about on the phone the unnamed tributary to Centennial Brook meets the technical definition
of a perennial stream under Stream Alterations even though that reach of stream, upstream of the UVM East
Campus Stormwater Treatment Facility Stormwater pond pipe outfall, is treating stormwater. Because this reach
of stream has been and must continue to be maintained as a functioning stormwater treatment facility requiring
maintenance, the preexisting use as a stormwater facilities precludes the ability to manage the reach as natural
and in recognition of these types of preexisting conditions in urban areas the Stream Alteration General
Permit allows these types of existing facilities to be maintained as “Non-Reporting” under C.2.1.4 of the Stream
Alteration General Permit provided:
a) The maintenance work is conducted in a manner which minimizes or avoids turbidity associated with the
activity
b) If the work is in association with agricultural lands, vegetated buffers required under the Required
Agricultural Practices (RAPs), Medium or Large Farm Operation Permits, or other applicable rules or permits,
including the CAFO General Permit, are maintained
c) Erosional channels are appropriately stabilized with vegetative or structural treatments
d) Sediments excavated to maintain channel capacity are disposed of outside of mapped Flood Hazard Areas
or river corridors
PAGE [ 2 ]
e) The work does not result in existing surface waters being converted to subsurface flows
f) Project improvements that move toward attainment of the Performance Standards outlined in Section
B.3.2. of the Stream Alteration General Permit are implemented wherever feasible.
The DoubleTree Hotel project is only proposing impacts in the River Corridor area that are adjacent to the
stormwater treatment facility. Because of this the area does not have to be maintained as natural and as such,
is a “Non-Reporting” use as long as the conditions above are met. The erosion control design included with this
submittal will ensure that the listed standards are met. With this finding we feel that the Purpose (12.07A) of
the regulation as listed below is achieved.
(1) Establish protection of the river corridor to provide rivers and streams with the lateral space
necessary to maintain or reestablish floodplain access and minimize erosion hazards through
natural, physical processes; The river corridor is protected because of the pre-existing and
previously approved stormwater treatment systems that are located within and at the beginning
of the mapped River Corridor.
(2) Allow for wise use of property within river corridors that minimizes potential damage to existing
structures and development from flood-related erosion; The associated grading from the planned
multi-use recreation path is above the water surface elevation of the existing pond so there will
be no flood related erosion. The recreation path and pavement reconstruction is generally within
an existing developed part of the site and therefore the benefits of the multi-use path is a wise
use of the property.
(3) Discourage encroachments in undeveloped river corridors; This is an existing developed portion of
river corridor.
(4) Protect and improve the quality of surface waters and streams within the City of South Burlington;
The stormwater treatment facilities are collecting and treating large urban watersheds.
(5) Provide sufficient space for wildlife habitat along rivers and streams; and, The area just north of the
project site is preserved for wildlife habitat and the associated river corridor in that area will
remain in its natural state
(6) Provide allowances for infill and redevelopment of designated centers that are within river
corridors. We believe the FBC Transect 4 zone is a designated center to allow for redevelopment
that benefits the public with the addition of the multi-use recreation path.