D-4. Foxwood: Approve Maintenance Agreement with Riley Purgatory Bluff Creek Watershed District 1 � Y
QT
•
CITY Of CIIANHASSEN
Chanhassen is a Community for Life-Providing for Today and Planning for Tomorrow
NH A �
MEMORANDUM
TO: Paul Oehme, Director of Public Works/City Engineer 1
FROM: Alyson Fauske, Assistant City Engineer
a
DATE: July 10, 2017
SUBJ: Foxwood Development—Approve Maintenance Agreement with
Riley Purgatory Bluff Creek Watershed District
PROPOSED MOTION
"The Chanhassen City Council approves a Maintenance Agreement with the Riley Purgatory
Bluff Creek Watershed District for the Foxwood Development."
Approval requires a simple majority vote of the City Council.
BACKGROUND
On July 25, 2016 the City Council approved the Foxwood final plat, which lies within the Riley
Purgatory Bluff Creek Watershed District(RPBCWD). At that time city and RPBCWD staff were
working to establish an agreement between the two agencies that would satisfy in perpetuity the
maintenance requirements for practices installed by a private developer and turned over to the city
for ownership and maintenance. Assuming such agreement would be made shortly after approval of
the Foxwood final plat, a RPBCWD declaration for the development was not pursued.
After much discussion and consultation with each agency's legal staff it was determined that it is not
in the best interest of either agency to enter into such an agreement; therefore, a maintenance
agreement with RPBCWD is now required for the Foxwood development. The agreement requires
the city to inspect and maintain the storm water facilities,buffers and water crossings and structures
within the development. These requirements are consistent with the city's current practices for
developments as well as the city's requirements under the MS4 permit.
Staff recommends that city council approve the maintenance agreement.
ATTACHMENT
1. Maintenance Agreement.
g:\eng\projects\f-j\foxwood\20170710 approve rpbcwd declaration.docx
PH 952.227.1100• www.ci.chanhassen.mn.us• FX 952.227.1110
7700 MARKET BOULEVARD • PO BOX 147 • CHANHASSEN • MINNESOTA 55317
MAINTENANCE AGREEMENT
Between the Riley Purgatory Bluff Creek Watershed District and
City of Chanhassen, MN
This Maintenance Agreement (Agreement) is made by and between the Riley Purgatory
Bluff Creek Watershed District, a watershed district with purposes and powers set forth
at Minnesota Statutes chapters 103B and 103D (RPBCWD), and City of Chanhassen, a
statutory city and body corporate and politic of the State of Minnesota (City).
Recitals and Statement of Purpose
WHEREAS pursuant to Minnesota Statutes section 103D.345, the RPBCWD has
adopted and implements the Wetland and Creek Buffers Rule, the Waterbody Crossings
and Structures Rule and the Stormwater Management Rule;
WHEREAS under the Wetland and Creek Buffers Rule, certain land development
activity triggers the requirement that the landowner record a declaration establishing
the landowner's perpetual obligation to protect undisturbed buffer adjacent to a creek
or wetland;
WHEREAS, under the Waterbody Crossings and Structures Rule, certain land
development activity requires the landowner to record a declaration establishing the
landowner's perpetual obligation to inspect and maintain waterbody crossings and
structures in accordance with approved plans;
WHEREAS under the Stormwater Management Rule, certain land development
activity triggers the requirement that the landowner record a declaration establishing
the landowner's perpetual obligation to inspect and maintain stormwater-management
facilities;
WHEREAS in each case, a public landowner, as an alternative to a recorded
instrument, may meet the maintenance requirement by documenting its obligations in
an unrecorded written agreement with the RPBCWD;
WHEREAS in accordance with the RPBCWD rules and as a condition of permit
2016-026, the City's perpetual obligation to maintain wetland and creek buffer,
waterbody crossings and stormwater facilities must be memorialized in a maintenance
agreement specifying requirements and restrictions;
WHEREAS City and the RPBCWD execute this Agreement to fulfill the condition of
permit no. 2016-026, and concur that it is binding and rests on mutual valuable
consideration;
THEREFORE City and RPBCWD agree as follows that City, at its cost, will inspect
and maintain the wetland and creek buffer, waterbody crossings and stormwater
facilities as shown in the site plan attached to and incorporated into this Agreement as
Exhibit A in perpetuity as follows:
1 . BUFFER AREAS
a. Buffer vegetation must not be cultivated, cropped, pastured, mowed,
fertilized, subject to the placement of mulch or yard waste, or
otherwise disturbed, except for periodic cutting or burning that
promotes the health of the buffer, actions to address disease or
invasive species, mowing for purposes of public safety, temporary
disturbance for placement or repair of buried utilities, or other actions
to maintain or improve buffer quality and performance, each as
approved by the District in advance in writing or when implemented
pursuant to a written maintenance plan approved by the District.
b. Diseased, noxious, invasive or otherwise hazardous trees or
vegetation may be selectively removed from buffer areas and trees
may be selectively pruned to maintain health.
c. Pesticides and herbicides may be used in accordance with Minnesota
Department of Agriculture rules and guidelines.
d. No fill, debris or other material will be placed within a buffer.
e. No structure or impervious cover (hard surface) may be created within
a buffer area beyond that shown in the scaled site plan attached to
this declaration as Exhibit A.
f. Permanent wetland buffer markers will be maintained in the locations
shown on the approved site plan attached as Exhibit A. Language
shall indicate the purpose of the buffer, restrictions, and the name
2
and website address of the Riley Purgatory Bluff Creek Watershed
District.
2. WATERBODY CROSSINGS & STRUCTURES
a. Crossings and structures in contact with the bed or bank of a waterbody will
be inspected at least once a year and maintained in good repair in perpetuity
to ensure adequate hydraulic and navigational capacity is retained in
accordance with approved plans; to ensure no net increase in the flood stage
beyond that achieved by the approved plans; to prevent adverse effects to
water quality, changes to the existing flowline/gradient and increased scour,
erosion or sedimentation; and minimizing the potential for obstruction of
the waterbody.
3. STORMWATER FACILITIES
a. Stormwater retention and treatment basin(s). Stormwater retention and
treatment basin(s) must be inspected at least once a year to determine if the
basin's retention and treatment characteristics are adequate and continue to
perform per design. Culverts and outfall structures must be inspected at
least annually and kept clear of any obstructions or sediment accumulation.
Sediment accumulation must be measured by a method accurate to within
one vertical foot. A storage treatment basin will be considered inadequate if
sediment has decreased the wet storage volume by 50 percent of its original
design volume. Based on this inspection, if the stormwater basin(s) is
identified for sediment cleanout, the basin(s) will be restored to its original
design contours and vegetation in disturbed areas restored within one year
of the inspection date.
b. Raingardens, infiltration basins and filtration basins. Raingardens, infiltration
basins and filtration basins will be inspected annually to ensure continued
live storage capacity at or above the design volume. Invasive vegetation,
excess sediment and debris will be removed as needed and healthy plant
growth will be maintained to ensure that the facilities continue to perform
per design.
c. Vegetated swales. Vegetated swales will remain free from mowing or other
vegetative disturbance, fertilizer application, yard or other waste disposal,
3
the placement of structures or any other alteration that impedes the function
of the vegetated swale.
d. Pervious pavement. Pervious pavement will be inspected after at least one
major storm per year and otherwise annually to ensure continuing
performance per design. Surface openings will be vacuumed in dry weather
to remove dry, encrusted sediment as necessary. Broken units that impair
the structural integrity of the surface will be replaced. If water stands for an
extended period of time, the base materials will be removed and replaced.
e. Underground storage facilities. Underground storage facilities will be
inspected at least annually to ensure continuing performance per design.
Capacity will be considered inadequate if sediment has decreased the
storage volume by 50 percent of the original design volume. Accumulated
debris and sediment will be removed, and inlet and outlet structures will be
kept clear of any flow impediments.
f. Grit chambers, sump catch basins and sump manholes. Grit chambers, sump
catch basins and sump manholes will be inspected in the spring, summer
and fall of each year. All sediment and debris will be removed as needed
such that the stormwater facilities operate as designed and permitted.
g. Proprietary stormwater facilities. Proprietary stormwater facilities will be
inspected at least annually and maintained as specified or recommended by
the manufacturer and/or installer as described in Exhibit A.
3. Reporting. City will submit to the RPBCWD annually a brief written report that
describes stormwater facility maintenance activities performed under this
declaration, including dates, locations of inspections and the maintenance
activities performed.
4. Property Transfer. If City conveys into private ownership a fee interest in the
property that is the subject of this Agreement, it shall require as a condition of
sale, and enforce: (a) that the purchaser record a declaration on the property
incorporating the maintenance requirements of this Agreement; and (b) that
recordation occur either before any other encumbrance is recorded on the
property or, if after, only as accompanied by a subordination and consent
executed by the encumbrance holder ensuring that the declaration will run with
the land in perpetuity. If City conveys into public ownership a fee interest in any
property that has become subject to this Agreement, it shall require as a
4
condition of the purchase and sale agreement that the purchaser accept an
assignment of all obligations vested under this Agreement.
5. This Agreement may be amended only in a writing signed by the parties.
6. The recitals are incorporated as a part of this Agreement.
IN WITNESS WHEREOF, the parties hereto have executed this Agreement.
RILEY PURGATORY BLUFF CREEK WATERSHED DISTRICT
By Date:
President, Board of Managers
CITY OF CHANHASSEN
By: Date:
Its Mayor
By: Date:
Its City Manager
5
I
.,_..• : ...::-.......\
-.BLS K / .>,,.; ..
ourwra
\:.1.......:
,t-2.---.. �i .•••• 'P
d
WETLAND 1 j."• . !
:....;/ Mph. I.-L_________Jr -----, \I 1B3 li I ,
7 I
f' 1 1 l\ I
// /' \".4/ra All1110 i t , I
lLWIMI I -..
.'-'-` , -- 7.' -----'- /4 ,/,`NrIpAllitaillINEMIINIIIIIIIIIIIIIIIS r-
OUTLOTa I 1] '
1 ' i
12 ;
/'
I Blr K 1 3
ST 1 (WET.5`,II.
L fi 1 J `iii
�. I I
i t i 1 i BLOCK 5
I
* !
••fr,OOTLOTC ..,,� 1�:..... ` -s 1 , i
�✓ /' 1\ 1 1
dWETLAND 2.,t::::::, %,,,,....... ..._/ 13 ) / iiir .............4 1
•• • • j
*.'•:::::::::•:* \/,''' 1
XE / ..,',"\• / it i
OUTLOTC /7
, Ai -....
i i T I BLOCK 541t .,, \\‘‘‘‘s\ss,
//,:..,• ourmTE
wilt,--
- 7
1 J
�i ``� I ® '/' ...• WETLANDS
I� % IBL IK3 13 � r
1- =Z..:. MAINTENANCE BMP LEGEND:
t.
.0-4 �.•_. ..
\A o l) \\ ► I� �'' " '°FE'i�: •:•::::::::::::::1 CITY MAINTAINED WETLAND BUFFER
11' -•- -• ,,` 4• INFILTRATION BASIN
CP
. ' .1‘.
.. .:..rtt I.% e`�.. WETLAND
l•.. \ toN'�t. ® SUMP MANHOLE
.7....„.:,..................;•••.;
:.,-- WETLAND! 1�T
‘1,7..%.•••••••••••• `'::'•'• '`. •■ WETLAND BUFFER MONUMENTS
i V..'.'.':::'�� y.: � 00;
�----""".• •',::' ;:• i",-,e' 1 STORM SEWER ENTERING/CROSSING
L r �® ti. >,..____ A WATERBODY
u
CLI
•;�.v' WETLAND4 X�� ♦ 1 TII\ L-
E �,.. `i:'.'.. !>, 111
I \ J
m
Lo
i
.
N 401
FOXWOOD- EXHIBIT A
CHANHASSEN, BY:
DRAWN BY:MINNESOTA DATE: ALLIANT
AKA ENGINEERING
I