01-16-24 Agenda and Packet
A.6:00 P.M. - CALL TO ORDER
B.PUBLIC HEARINGS
B.1 Ordinance XXX: Amending Lot Cover Standards in the Residential Single Family (RSF)
Zoning District.
B.2 Ordinance XXX: Amending Lot Cover Standards in the Shoreland Overlay District.
C.GENERAL BUSINESS
D.APPROVAL OF MINUTES
D.1 Approve Planning Commission Meeting Minutes dated December 5, 2023
E.COMMISSION PRESENTATIONS
F.ADMINISTRATIVE PRESENTATIONS
G.CORRESPONDENCE DISCUSSION
H.ADJOURNMENT
I.OPEN DISCUSSION
AGENDA
CHANHASSEN PLANNING COMMISSION
TUESDAY, JANUARY 16, 2024
CITY COUNCIL CHAMBERS, 7700 MARKET BOULEVARD
NOTE: Planning Commission meetings are scheduled to end by 9:00 p.m. as outlined in the official by-laws. We will
make every attempt to complete the hearing for each item on the agenda. If, however, this does not appear to be possible,
the Chairperson will notify those present and offer rescheduling options. Items thus pulled from consideration will be
listed first on the agenda at the next Commission meeting.
If a constituent or resident sends an email to staff or the Planning Commission, it must be made part of the public record
based on State Statute. If a constituent or resident sends an email to the Mayor and City Council, it is up to each individual
City Council member and Mayor if they want it to be made part of the public record or not. There is no State Statute that
forces the Mayor or City Council to share that information with the public or be made part of the public record. Under
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State Statute, staff cannot remove comments or letters provided as part of the public input process.
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Planning Commission Item
January 16, 2024
Item Ordinance XXX: Amending Lot Cover Standards in the Residential Single
Family (RSF) Zoning District.
File No.Item No: B.1
Agenda Section PUBLIC HEARINGS
Prepared By Eric Maass, Planning Director
Applicant
Present Zoning
Land Use
Acerage
Density
Applicable
Regulations
SUGGESTED ACTION
The Planning Commission should provide a formal recommendation to the City Council on the
proposed ordinance amendment.
SUMMARY
The City Council has considered options for amending the city's ordinances related to lot cover. The
City Council gave direction to city staff to prepare a draft ordinance revising language which currently
allows for impervious lot cover up to 30% within the Residential Single Family (RSF) zoning district.
BACKGROUND
Currently the RSF zoning district allows for a base of 25% impervious lot cover. Property owners can
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have an additional 5% lot cover through the use of permeable pavers. The ordinance as drafted would
allow for up to 30% impervious lot cover but not dictate that a property owner utilize pervious pavers in
order to do so.
As previously presented, pervious pavers can be costly to install and require routine maintenance. If
installed incorrectly or not properly maintained the pavers can revert from their initial pervious state
into an impervious state. The ordinance amendment would lift the pervious paver requirement and
allow for the 30% lot cover to be available for all RSF property owners.
The City currently has 42 Planned Unit Development (PUD's) in place. 39 of the possible 42 PUD's
stipulate within the PUD ordinance the specific governance for lot cover for those developments most of
which allow for a lot cover of at least 30%. The three PUD's which indicate that the underlying RSF
zoning shall regulate the lot cover include Ches Mar Farm & Trail, Lake Susan Hills, and Mission
Hills. Attached to this case is a table summarizing the various PUDs in place and their corresponding
lot cover limitations.
DISCUSSION
RECOMMENDATION
Staff is seeking a formal recommendation from the Planning Commission to be forwarded to the City
Council.
ATTACHMENTS
Ordinance 722 Draft Lot Cover in RSF.docx
Residential PUD Lot Cover Table
Water Resources Dept - Staff Report
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Page 1
CITY OF CHANHASSEN
CARVER AND HENNEPIN COUNTIES, MINNESOTA
ORDINANCE NO. XXX
AN ORDINANCE AMENDING CHAPTER 20, ZONING,
OF THE CHANHASSEN CITY CODE AMENDING LOT COVER STANDARDS IN
THE RESIDENTIAL SINGLE FAMILY (RSF) ZONING DISTRICT
THE CITY COUNCIL OF THE CITY OF CHANHASSEN, MINNESOTA,
ORDAINS:
SECTION 1.Section 20-615 Lot Requirements and Setbacks of the City Code, City of
Chanhassen, Minnesota, is hereby amended to read as follows:
Section 20-615 Lot Requirements and Setbacks
The following minimum requirements shall be observed in an "RSF" District subject to additional
requirements, exceptions and modifications setforth in thischapterand chapter18:
(a) The minimum lot area is 15,000 square feet. For neck or flag lots, the lot area
requirementsshallbemetaftertheareacontainedwithinthe"neck"hasbeenexcluded
from consideration.
(b) Theminimumlotfrontageis90feet,exceptthatlotsfrontingonacul-de-sac"bubble"
shall be 90 feet in width at the building setback line. The location of this lot is
conceptually illustrated below.
FrontageMeasuredatSetback Line
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Page 2
(c)The minimum lot depth is 125 feet.
(d)Lot width on neck or flag lots and lots accessed by private streets shall be 100 feet as
measured at the front building setback line.The location of these lots is conceptually
illustrated below.
Neck/Flag Lots
(e)The maximum lot coverage for all structures and pavedimpervious surfaces is
30 percent,unless further restricted by the City's Shoreland Management District of which no
more than 25 percent can be impervious surfaces. For flag/neck lots neither the area within the
neck, nor the lot coverage of the driveway within the neck shall be included within the
calculation of the lot area or lot coverage of the lot.
(f)The setbacks are as follows:
(1)For front yards, 30 feet.
(2)For rear yards, 30 feet.
(3)For side yards, ten feet.
(g)The setbacks for lots served by private streets and/or neck lots are as follows:
(1) For front yard, 30 feet. The front yard shall be the lot line nearest the public
right-of-way that provides access to the parcel unless otherwise designated in
accordance with section 20-922. The rear yard lot line is to be located
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Page 3
opposite from the front lot line with the remaining exposures treated as side
lot lines. On neck lots the front yard setback shall be measured at the point
nearest the front lot line where the lot achieves a 100-foot minimum width.
(2) For rear yards, 30 feet.
(3) For side yards, ten feet.
(h) The maximum height is as follows:
(1) For the principal structure, three stories/35 feet.
(2) For accessory structures, one story/20 feet.
SECTION 2.This ordinance shall be effective immediately after its passage and publication.
PASSED AND ADOPTED this day of , 2024 by the City Council of the
City of Chanhassen, Minnesota.
ATTEST:
Kim Meuwissen City Clerk Elise Ryan, Mayor
(Published in the Chanhassen Villager on )
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SITE # PROJECT FILE NO.
DESIGN
STANDARD LOT COVER LISTED DETAILS NOTES
1 Minnewashta Creek 75-1 SUB Design Standard Y 25%
2 Red Cedar Cove Townhouses 85-5 PUD Design Standard Y 25%
Can be averaged throughout the entire
development
3 Ches Mar Farm & Trail 84-2, 88-1, 91-1 PUD Design Standard N
4a Meadows at Longacres 92-4 PUD Design Standard Y 25%
4b Woods at Longacres 93-3 PUD Design Standard Y 25%
5 Highlands at Bluff Creek 2003-3 PUD Design Standard Y 30%
6 Arboretum Village 99-2 PUD Design Standard Y 70% commercial / 30% total
site
7 Pheasant Hills 83-1 PUD Design Standard Y 30%
8 The Park 2019-01 PUD Design Standard Y 36.7% for 90 ft lots / 52% for
65 ft lots
Preserved 50 acres of woods adjacent
top Lake Ann
9 Walnut Grove 96-04 PUD Design Standard Y 30%
10 WillowRidge 91-3 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
11 Chaparral 78-01, 79-3 PUD Design Standard Y 30%
Can be averaged throughout the entire
development
12 Triple Crown Estates 85-2 PUD Design Standard Y 30%
13 Chanhassen Vista 86-1 PUD Design Standard Y 30%
14 Saratoga 1st and 2nd Additions 77-1 PUD Design Standard Y 30%
Can be averaged throughout the entire
development
15 Saratoga 3rd Addition 98-2 PUD Design Standard Y 65% Multi-family residential
16 Western Hills 79-6 PUD Design Standard Y 30%
17 Laredo Lane 75-2 PUD Design Standard Y 30%
18 Oak Ponds 92-3 PUD Design Standard Y 50% Multi-family residential
19 Near Mountain 79-2 PUD Design Standard Y 25% / 25% / 30% / 30% Varies based on housing types
20 Fox Hollow 84-1 PUD Design Standard Y 25%
Can be averaged throughout the entire
development
21 South Lotus Lake 85-4 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
22 South Lotus Villas 89-4 SPR Design Standard Y 54% High-density residential
23 Townhomes at Creekside 96-3 PUD Design Standard Y 30%
Averaged from the entire development,
including the public and private streets
and Outlots, may not exceed 30
percent hard coverage. Individual lots
will exceed the 30 percent site
coverage.
24 Trotters Ridge 93-2 PUD Design Standard Y 30%
25 Lynmore Addition 98-1 PUD Design Standard Y 30%
26 Autumn Ridge Townhouses 93-5 PUD Design Standard Y 30%
Averaged from the entire development,
including the public and private streets
and Outlots, may not exceed 30
percent hard coverage. Individual lots
will exceed the 30 percent site
coverage.
27 Lake Susan Hills 87-3 PUD Design Standard N Includes RSF, R-8, and R-12/16
28 Chanhassen Hills 85-6 PUD Design Standard Y 25%
29 West Park 2017-12 PUD Design Standard Y 50% RSF and Mixed Use
30 Chanhassen Gateway 2006-05 PUD Design Standard Y 50% Residential / 70%
Commercial and Office
31 Hidden Valley 85-1 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
32 Mission Hills 93-4 PUD Design Standard N
33 Preserve at Rice Lake 2013-12 PUD Design Standard Y 30%
34 Southwest Village 2006-18 PUD Design Standard Y 50% / 70% Commercial and
Transit Facility
35 North Bay 95-1 PUD Design Standard Y 50%
The entire development, including the
public and private streets and Outlots,
may not exceed 50
percent hard coverage. Individual lots
will exceed the 50 percent site
coverage. (Townhomes)
36 Lakeside 2006-26 PUD Design Standard Y 50%
The entire development, including the
public and private streets and Outlots,
may not exceed 50
percent hard coverage. Individual lots
will exceed the 50 percent site
coverage. (Twinhomes, townhomes,
and condos)
37 Springfield 1993-06 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
38 Arbor Glen 2015-16 PUD Design Standard Y 59% Residential
The entire development, including the
private street and outlots, may not
exceed 25
percent hard coverage.
39 Preserve at Bluff Creek 2006-14 PUD Design Standard Y 45% Residential
The entire development, including the
public and private streets and Outlots,
may not
exceed 30 percent hard coverage.
Individual lots will exceed the 30
percent site coverage.
40 Liberty on Bluff Creek 2005-11 PUD Design Standard Y 30% Averaged from the entire development.
41 Camden Ridge 2013-13 PUD Design Standard Y 25% Shoreland / 35% Total
The entire development, including the
public and private streets and Outlots,
may not exceed 35
percent hard coverage. Individual lots
may exceed the 35 percent site
coverage. Lots within the
shoreland district may not exceed 25
percent site coverage.
42 Lake Lucy Island 2020-23 PUD Design Standard Y 25%
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Memorandum
To:Eric Maass, Planning Director
From:Joe Seidl, Water Resources Engineer
CC: Charles Howley, Public Works Director/City Engineer
George Bender, Assistant City Engineer
Erik Henricksen, Project Engineer
Date:1/10/2024
Re:Amending Lot Cover Standards within the Shoreland Overlay
District and the Residential Single Family Zoning District
Introduction
The City of Chanhassen is considering increasing the maximum amount of lot cover allowed
from 25% to 30% within both the Shoreland Overlay District and the Residential Single Family
Zoning District. The Water Resources Division does not support the ordinance amendments to
increase lot cover. Water Resources staff believe that the increase in lot cover without the
construction of offsetting Best Management Practices (BMPs) has the potential to cause
adverse impacts. Lot cover or impermeable surfaces caused by urbanization and the
construction of buildings, pavement, etc. can have several negative effects on downstream
lakes, streams, and wetlands and the overall environment. Water Resources and Planning staff
have however worked successfully with the DNR to incorporate strategies related to the
Shoreland Overlay District that help mitigate potential effects.
The potential effects can include:
Increased runoff: Lot cover prevents rainwater from infiltrating into the ground and/or
uptake by vegetation (trees and shrubs) . Instead, the water flows over the surface and
increases the volume and velocity (rate) of the runoff; which can cause flooding and
erosion in nearby streams and rivers, and could overwhelm existing downstream storm
sewer collection and treatment systems, especially if those systems are already
undersized due to elevated rainfall amounts and intensity.
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Reduced infiltration: When rainwater cannot penetrate the soil, it cannot recharge
groundwater supplies. This can lead to a decrease in the water table, which can cause
wells to run dry and streams to dry up.
Water quality degradation: As runoff flows over the land, it picks up pollutants such as
oil, fertilizers, and pesticides, and carries them into nearby waterways. This can lead to
decreased water quality and harm aquatic ecosystems and the organisms that depend
on them.
Increased temperature: Urban areas with increased lot cover tend to be hotter than
surrounding areas due to the absorption of heat by buildings and pavement. This can
lead to warmer water temperatures in streams and rivers, which can negatively impact
aquatic life.
The increase in stormwater volumes and runoff rates generated by impervious surfaces can
cause issues if not mitigated by the construction of stormwater Best Management Practices
(BMPs).
The following sections provide background information to inform Chanhassen’s Planning
Commission and City Council.
What is a stormwater BMP?
Stormwater Best Management Practices (BMPs) are a set of techniques and practices designed
to manage and treat stormwater runoff, which is rainwater and other precipitation that flows
over the ground and into storm drains or other bodies of water. Stormwater BMPs are designed
to reduce the negative impacts of stormwater runoff, such as flooding, erosion, and pollution
generated by impervious surfaces.
Overall, stormwater BMPs work by mimicking natural systems and processes to manage and
treat stormwater runoff by facilitating infiltration, filtration, settling, and evapotranspiration.
Commonly used stormwater BMPs include infiltration basins, biofiltration basins, wet ponds,
rain gardens, green roofs, and permeable pavers.
Proposed Lot Cover Ordinance Amendment in the RSF Zoning District
The proposed Lot Cover Ordinance within the Residential Single Family Zoning District does not
have any provisions included that require the construction of offsetting BMPs. The ordinance
amendment would increase the maximum lot cover allowed within a property from 25% to
30%.
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Proposed Lot Cover Ordinance Amendment in the Shoreland Overlay District
The proposed Lot Cover Ordinance within the Shoreland Overlay District would increase the
maximum lot cover allowed for a property from 25% to 30% and includes provisions that would
require the applicant to construct and maintain a BMP to offset the increase in impervious
surface constructed. For properties adjacent to water resources the BMP would be a natural
vegetative buffer sized as a 1 to 1 ratio to the impervious area over the 25% threshold. All other
properties would be required to construct a BMP with a design approved by Water Resources
staff. City Staff worked with the Department of Natural Resources Hydrologist to develop the
proposed ordinance. The ordinance would allow lot cover flexibility within the Shoreland
Overlay district and would help the DNR achieve their goal of naturalizing the shoreland. The
provisions include the creation of a maintenance declaration that would be recorded against
the property to ensure the stormwater treatment improvement would be protected.
How are impervious surfaces regulated?
The construction and reconstruction of impervious surfaces are regulated locally by the City of
Chanhassen and by local Watershed Districts, including the Riley Purgatory Bluff Creek
Watershed District (RPBCWD), Minnehaha Creek Watershed District (MCWD), Lower Minnesota
River Watershed District (LMRWD) and the Carver County Water Management Organization
(CCWMO). The Metropolitan Pollution Control Agency (MPCA) also regulates the construction
of impervious surfaces through the Municipal Separate Storm Sewer System (MS4) Permit and
National Discharge Elimination System Construction Stormwater (NPDES) Permit.
In general, when a project is proposed, the amount of impervious surface being constructed is
quantified and converted into a Water Quality Volume (WQV) by multiplying the new
impervious surface area by 1.1 inch. For example, a project creating 1 acre of new impervious
surface would be required to design BMPs to treat a WQV of:
1 Acre =43,560 Square Feet X 1.1 Inch/(12 Inch/Foot) = 3,993 Cubic Feet of Treatment Required
In this example, as part of the project design, the project proposers would implement BMPs to
treat the WQV and create Hydrologic and Hydraulic (H&H) Models to compare existing and
proposed conditions to ensure stormwater is managed properly and will not create adverse
impacts downstream.
The requirements for the construction of BMPs and H&H modeling are generally associated
with defined amounts of impervious surface. For example, the RPBCWD has a stormwater
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treatment requirement trigger set to 5,000 square feet of impervious surface being
constructed. The typical residential improvements (patios, decks, additions, etc.) governed by
the proposed ordinance amendment would not trigger the threshold to mandate stormwater
treatment.
This gap in regulation creates a problem because the smaller individual projects might not
create visible issues, but the cumulative impact of many smaller projects would create
stormwater management problems.
Standard practice is to ensure subdivision development projects design BMPs for the maximum
lot cover allowed within the parcels generated. Any increase to the lot cover after the fact
would create additional stormwater volumes in excess to those accounted for in the original
design.
What are potential impacts that residents could experience?
The existing stormwater infrastructure within Chanhassen would still serve to offset some of
the impacts noted above, including flood mitigation and pollutant removal. However, the
infrastructure was not designed for the increased lot cover allowances proposed nor the
additional stormwater runoff that would be generated. In general, Chanhassen stormwater
infrastructure is undersized due to when it was designed, therefore the additional runoff
generated would act to further tax our drainage system. Over time, if unmitigated lot cover
were to increase, residents could experience some of the following impacts:
Increased pollutant loads in stormwater ponds and water resources, which would
degrade water quality and increase the frequency and scale of algae blooms.
Increased frequency and duration of street flooding and high water levels of stormwater
ponds and water resources.
Increased erosion of natural and manmade stormwater conveyance systems.
Increased frequency and duration of nuisance drainage issues, such as wet yards, sump
pump discharge, and standing water.
How would the stormwater BMP improvements be regulated and managed for the Shoreland
Overlay District?
City staff would ensure the natural vegetative buffer or stormwater BMP was sized correctly as
regulated by City Ordinance during review of the building permit. Template maintenance
agreements and buffer declarations are available and would be provided to project proposers.
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After construction, the BMP would be added into the asset management database managed by
the City’s engineering department. City staff would need to expand the current program that
tracks and completes inspections on private BMPs to ensure the assets function as designed.
When problems are identified, City staff would work with residents to get the issues resolved.
Depending on the scale of the problem and the resident’s commitment to complete the work,
the amount of time it would take to resolve a specific problem could vary greatly.
How do other agencies view the Proposed Lot Cover Ordinance Amendments?
The proposed ordinance changes to increase lot cover were coordinated with the water
management organizations that regulate the City of Chanhassen, including the Minnesota
Department of Natural Resources (DNR), RPBCWD, MCWD, MRWD, and CCWMO. In general,
these agencies are opposed to regulations that would generate additional impervious surfaces
without the construction of corresponding BMPs to mitigate adverse impacts. Correspondence
and memos provided by the agencies are included in the agenda item packet.
What is the guidance from Chanhassen’s Local Stormwater Management Plan?
The Local Stormwater Management Plan adopted in December of 2018 is intended to provide
the City of Chanhassen with information and direction in the administration and
implementation of water resource management activities within the City during the period
2018-2027. It serves as a guide to projects, provides for effective allocation of resources, and
sets forth a funding plan for projects and programs over the next 5 to 10 years.
The Local Stormwater Management Plan includes goals and policies to help achieve those goals.
Included below are the most pertinent sections regarding the proposed Ordinance
Amendments that would increase maximum lot cover allowances:
Goal 1 reads: “Promote abstraction through infiltration, reuse and other methods where
practicable to do so to provide flood protection, ground water recharge and improved water
quality.”
Within Goal 1 the two most relevant polices to the proposed ordinance amendments are
outlined below:
Policy 1.4. Continue to stringently enforce lot coverage requirements set forth in City Code
and development contracts.
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Policy 1.2. Require all development and redevelopment projects to demonstrate no net
increase in the annual runoff water volume discharged from the site compared
to pre-development conditions.
The proposed ordinance amendments within the RSF Zoning District are in direct conflict with
the goals and policies of the Local Surface Water Management Plan. Without offsetting BMPs,
the increased hardcover would act to inhibit infiltration, reduce flood protection and
groundwater recharge, and decrease water quality.
Goal 2 reads: “Achieve water quality standards in lakes, streams, and wetlands consistent
with their designated uses and established classifications.”
Within Goal 2 the policy outlined that is most relevant to the proposed ordinance amendment
that would increase the maximum Lot Cover allowance within the Shoreland Management
District is:
Policy 2.15 Maintain a shoreland ordinance consistent with DNR requirements and
recommendations to promote and encourage shoreland protection.
The proposed Lot Cover ordinance modifications were coordinated with the DNR and received
conditional approval from the local area Hydrologist. While in general increases in lot cover are
not supported by the DNR, the ordinance changes within the Shoreland Overlay District and the
regulations that mandate the creation of natural vegetative buffers and stormwater BMPs are
viewed as a reasonable trade to allow Chanhassen residents flexibility for improvements on
their property that would increase lot cover. Therefore, the proposed ordinance changes within
the Shoreland overlay district are consistent with Policy 2.15.
It must be noted that water quality within large portions of the City of Chanhassen is below
standards set by the MPCA. Several of the local lakes and streams are on the impaired waters
list and therefore Chanhassen is not achieving Goal 2 of the Local Surface Water Management
Plan. The proposed Ordinance amendments within the Shoreland Overlay District do not apply
to reconstructed impervious surfaces and therefore only act to preserve the current state of
the local water resources.
The Water Resources Department recommends that the ordinance proposed be amended to
include BMP requirements for reconstructed impervious areas to improve the quality and
character of receiving water bodies as redevelopment occurs.
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Planning Commission Item
January 16, 2024
Item Ordinance XXX: Amending Lot Cover Standards in the Shoreland Overlay
District.
File No.Item No: B.2
Agenda Section PUBLIC HEARINGS
Prepared By Eric Maass, Planning Director
Applicant
Present Zoning
Land Use
Acerage
Density
Applicable
Regulations
SUGGESTED ACTION
The Planning Commission should provide a recommendation on the draft ordinance.
SUMMARY
The City Council has considered options for amending the city's ordinances such that greater lot cover
would be allowable that is comparable to neighboring communities. The City Council gave direction to
city staff to prepare a draft ordinance allowing up to 30% impervious lot cover within the shoreland
overlay zoning district and to work with the Department of Natural Resources (DNR) on the proposed
ordinance amendment.
Any amendments to the city's Shoreland Overlay Zoning Ordinance requires DNR review and approval
of the ordinance revisions. Staff has collaborated with the area hydrologist and DNR land use specialist
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on the ordinance included in this agenda item. The ordinance as drafted has conditional approval from
the DNR through it's implementation flexibility process. The ordinance as drafted satisfies the DNR's
requirements for "alternate approaches" as a result of the required riparian vegetative buffers for new
impervious surface area between 25% and 30% of the total lot area. The "alternate approaches"
implementation flexibility can be found under Minnesota Rules 6120.2800 Subp. 3.
BACKGROUND
The attached ordinance amending the Shoreland Overlay Zoning District would allow a maximum of
30% impervious surface area for lots which were established prior to January 1, 1976. Currently the
city’s shoreland overlay zoning ordinance allows for a maximum impervious surface area of 25% as
outlined by the DNR’s model ordinance.
The city currently has a total of 444 riparian lots. Of that, 253 were established prior to 1976. Those
253 lots would be eligible for up to 30% impervious lot coverage under the proposed ordinance
amendment. The city has mapped requested variances and an overwhelming number of the total
variances requested have been on lots which have been identified as lots established prior to 1976.
These lots are much narrower, some just 40 feet wide, than what is currently required for lot width by
ordinance and as a result are also much smaller in total lot area than what ordinances would currently
require. Lot cover variances requested for reasonable requests on substandard lots have typically been
approved by the city when a practical difficulty can be established as required by state statute. The city
has denied various lot cover variance requests if a practical difficulty could not be established because
of a substandard lot or other practical difficulty established by statute. The proposed ordinance
amendment would alleviate many variance requests while empowering city staff to still require that
Best Management Practices (BMPs) be utilized to mitigate the impact of increased impervious surface
area.
The draft ordinance requires that a BMP be established that is commensurate with the additional
impervious lot cover between 25% and 30% of the lot area. The draft ordinance stipulates that an
operations and maintenance agreement be executed and recorded against the property when necessary
so that the BMP could be inspected by the city to ensure its existence and functionality over time. The
ordinance also establishes the information required to be provided at the time of permit application so
that city staff can properly review and verify BMP requirements.
The draft ordinance also stipulates that an extra protection not typically required by ordinance be taken
if the property is a riparian lot. That extra protection is establishment of a shoreline vegetative buffer.
The shoreline vegetative buffer would qualify as a BMP and may satisfy the BMP requirement. The
total area of the shoreline vegetative buffer is proposed to be equal in size to the impervious area
between 25%-30% of the total lot area. The vegetative buffer area is proposed to have a length along the
shoreline of at least 25% of the total linear lake frontage. The width of the shoreline vegetative buffer
will be the width necessary so that the shoreline length multiplied by the width is then equal to the total
square feet of impervious area.
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Example:
A 200 square foot paver patio is being proposed on a riparian lot that has 50 feet of lake frontage
and which is already at 25.0% lot cover. The lot would have 200 square feet of impervious area
over the standard 25% threshold as a result.
A 200 square foot shoreline vegetative buffer required.
The shoreline vegetative buffer would have to have a length of at least 20 feet of lake
frontage.
The shoreline vegetative buffer would then have to be 10 feet wide.
The 20 foot lake frontage multiplied by the 10 foot wide (depth) = 200 square foot total
area of shoreline vegetative buffer.
Note: If the property owner desired for additional riparian length of the buffer area, the depth could be
reduced such that the total square feet of the buffer area remained equal to the 200 square feet outlined
in the above example.
DISCUSSION
RECOMMENDATION
The DNR has provided conditional approval of the proposed ordinance revisions to the shoreland
overlay district.
ATTACHMENTS
Ordinance 721: Amending Shoreland Overlay Lot Cover
DNR - Conditional Approval Notice
Map showing lots zoned as Residential Single Family (RSF) and Shoreland Overlay Zoning District
Boundary
Map showing date of riparian lot establishment and prior variance requests
Existing residential PUDs and lot cover allowance
Water Resources Dept - Staff Report
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Page 1
CITY OF CHANHASSEN
CARVER AND HENNEPIN COUNTIES, MINNESOTA
ORDINANCE NO. XXX
AN ORDINANCE AMENDING CHAPTER 20, ZONING,
OF THE CHANHASSEN CITY CODE AMENDING LOT COVER STANDARDS IN
THE SHORELAND OVERLAY DISTRICT
THE CITY COUNCIL OF THE CITY OF CHANHASSEN, MINNESOTA,
ORDAINS:
SECTION 1.Section 20-485 Stormwater Management of the City Code, City of
Chanhassen, Minnesota, is hereby amended to read as follows:
Section 20-485 Stormwater Management
Lotcoverage of lots shall not exceed 25 percentof the lot area, exceptas follows:
(a)Thirty-five percentformedium/high densityresidentialzones;and
(b)Seventypercentin industrialzoneswithin the LakeSusan Shoreland District.
(a) 30percent imperviousshallbe allowed forlots zoned Residential Single Family
(RSF) which were platted prior to January 1, 1976 with the following conditions:
(1) Riparian Lots
a. When exceeding 25 percent impervious coverage, riparian lots shall
be required to have a shoreline vegetativebufferarea equalin size to
the new impervious area proposed over 25 percent of the lot area.
(Example:100squarefeetofimperviousareawillrequire100square
feet of shoreline vegetative buffer area).
1. Theshorelinevegetativebufferwillbe required to encompass
at least 25 percent or 20 feet of the linear water frontage,
whichever is greater. The buffer width shall be the width
necessary to achieve the required buffer area. (For example,
100 square feet of impervious area required with 25 feet of
buffer length along the shoreline would require a vegetative
buffer width of 4 feet.)
2. Ifthevegetative required isdetermined to beinfeasiblebythe
City Engineer, alternative Best Management Practices
(BMPs) shall be installed as outlined in section B.
3. Accessto thelakeforswimming ordock useshallbe
maintained.
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Page 2
4.ThevegetativebuffermaysatisfytheBMPrequirement
outlined below.
b. Thefollowing shallbeprovided atthetime ofpermitapplication:
1. Pre-andpost-projectlotcovercalculations.
2. Water Quality Volume shall be calculated by 1.1 inch
multipliedbytheareainsquarefeetofimperviousareaover
25 percent.
3. BMPs shall be designed to treat the calculated amount of
WaterQualityVolumecreatedbytheproposedimpervious
area.
4. Project plans on a scaled survey shall show the proposed
impervious surface as well as the offsetting location and
designofBMPs.Thiscouldincludenativevegetativebuffers,
rain gardens, rain barrels, infiltration/biofiltration
basins/swales, etc.)
5. Anerosionandsedimentcontrolplaninaccordancewith
Section 19-145 of the City Code.
6. Additional information, such as Hydrologic and Hydraulic
Modeling,planscertifiedbyaprofessionalengineer,etc.,may
be required as determined by the City Engineer when there is
reasonable cause for concern of the impacts of the increased
stormwater runoff.
c. Changes in stormwater runoff shallnotcause adverse impacts to
adjacent and downstream infrastructure.
d. BMPs installed shall be privately owned and may require an
OperationsandMaintenanceAgreementtoberecordedagainstthe
property at the discretion of the City Engineer.
e. Vegetative buffer areas shall be protected in an easement recorded
againsttheproperty, and monumentsshallbeinstalled attheeasement
boundary
(2) Non-Riparian Lots
a. Thefollowing shallbeprovided atthetime ofpermitapplication.
1. Pre-andpost-projectlotcovercalculations.
2. Water Quality Volume shall be calculated by 1.1 inch
multipliedbytheareainsquarefeetofimperviousareaover
25 percent.
3. BMPs shall be designed to treat the calculated amount of
WaterQualityVolumecreatedbytheproposedimpervious
area.
4. Project plans on a scaled survey shall show the proposed
impervious surface as well as the offsetting location and
designofBMPs.Thiscouldincludenativevegetativebuffers,
rain gardens, rain barrels, infiltration/biofiltration
basins/swales. etc.
5. Anerosionand sedimentcontrolplanin accordance with
19
Page 3
Section 19-145 ofCity Code.
6. Additional information such as Hydrologic and Hydraulic
Modeling,planscertified byaprofessional engineer,etc.may
berequiredasdetermined bytheCityEngineerwhen thereis
reasonable cause for concern of the impacts by the increased
stormwater runoff.
b. Changes in stormwaterrunoff shallnotcause adverse impacts to
adjacent and downstream infrastructure.
c. BMPs installed shall be privately owned and may require an
OperationsandMaintenanceAgreementtoberecordedagainstthe
property.
(b) 35 percent formedium/high-density residentialzones;and
(c) 70percentin industrialzoneswithin the Lake Susan Shoreland District.
SECTION 2.This ordinance shall be effective immediately after its passage and publication.
PASSED AND ADOPTED this day of , 2024 by the City Council of the
City of Chanhassen, Minnesota.
ATTEST:
Kim Meuwissen City Clerk Elise Ryan, Mayor
(Published in the Chanhassen Villager on )
20
Revised 10/05/2022
1801 South Oak Street
Lake City, MN 55041
December 14, 2023
Eric Maass
Chanhassen Planning Director
EMaass@chanhassenmn.gov
Re: Conditional Approval of Chanhassen Shoreland Ordinance Amendment
Dear Eric:
Thank you for sending your proposed shoreland ordinance amendment to the DNR for conditional
approval review. I am pleased to inform you that the proposed amendment is substantially compliant
with the statewide rules and hereby approved, provided all of the conditions of approval and terms of
implementation flexibility in this letter are met.
Ordinance Evaluation
We have reviewed Section 20-485 (Stormwater Management), which you propose to amend in your
draft ordinance (received on December 13, 2023) for compliance with state shoreland rules (MR
6120.2500 – 6120.3900). Our conditional approval only applies to Section 20-485.
Terms of Implementation Flexibility
The following terms of implementation flexibility (per Minn. R. 6120.2800 Subp. 3), which were sent to
us December 13, 2023, are included in the ordinance we are conditionally approving. These terms of
implementation flexibility are also conditions of approval. If any of the offsetting higher standards are
eliminated or protection levels reduced in future ordinance amendments without DNR approval,
approval of implementation flexibility is rescinded.
Provisions not meeting minimum standards:
• Maximum of 30% impervious surface for lots within the shoreland overlay district platted prior
to January 1, 1976
Offsetting higher standards:
1) Riparian Lots
21
Revised 10/05/2022
a. When exceeding 25% impervious coverage, riparian lots shall be required to have a
shoreline vegetative buffer area equal in size to the new impervious area proposed over
25% of the lot area.
1. The shoreline vegetative buffer will be required to encompass at least 25% or 20
feet of the linear water frontage, whichever is greater. The buffer width shall be the
width necessary to achieve the required buffer area.
2. If the vegetative buffer required is determined to be infeasible by the City Engineer,
alternative Best Management Practices (BMP[s]) shall be installed as outlined in
section B.
3. Access to the lake for swimming or dock use shall be maintained.
4. The vegetative buffer may satisfy the BMP requirement outlined below.
b. The following shall be provided at the time of permit application:
1. Pre and post project lot cover calculations.
2. Water Quality Volume shall be calculated by 1.1 inch multiplied by the area in
square feet of impervious area over 25%.
3. BMPs shall be designed to treat the calculated amount of Water Quality Volume
created by the proposed impervious area.
4. Project plans on a scaled survey shall show the proposed impervious surface as well
as the offsetting location and design of BMPs. This could include native vegetative
buffers, rain gardens, rain barrels, infiltration/biofiltration basins/swales, etc.)
5. An erosion and sediment control plan in accordance with Section 19-145 of city
code.
6. Additional information such as Hydrologic and Hydraulic Modeling, plans certified by
a professional engineer, etc. may be required as determined by the City Engineer
when there is reasonable cause for concern of the impacts by the increased
stormwater runoff.
c. Changes in stormwater runoff shall not cause adverse impacts to adjacent and downstream
infrastructure.
d. BMPs installed shall be privately owned and may require an Operations and Maintenance
Agreement to be recorded against the property at the discretion of the City Engineer.
e. Vegetative buffer areas shall be protected in an easement recorded against the property
and monuments shall be installed at the easement boundary.
2) Non-Riparian Lots
a. The following shall be provided at the time of permit application:
1. Pre and post project lot cover calculations.
2. Water Quality Volume shall be calculated by 1.1 inch multiplied by the area in square
feet of impervious area over 25%.
3. BMPs shall be designed to treat the calculated amount of Water Quality Volume created
by the proposed impervious area.
4. Project plans on a scaled survey shall show the proposed impervious surface as well as
the offsetting location and design of BMPs. This could include native vegetative buffers,
rain gardens, rain barrels, infiltration/biofiltration basins/swales, etc.
5. An erosion and sediment control plan in accordance with Section 19-145 of city code.
6. Additional information such as Hydrologic and Hydraulic Modeling, plans certified by a
professional engineer, etc. may be required as determined by the City Engineer when
22
Revised 10/05/2022
there is reasonable cause for concern of the impacts by the increased stormwater
runoff.
b. Changes in stormwater runoff shall not cause adverse impacts to adjacent and downstream
infrastructure.
c. BMPs installed shall be privately owned and may require an Operations and Maintenance
Agreement to be recorded against the property.
Next Steps
Following are the steps for completing and receiving final DNR approval for your ordinance amendment:
1. The city council adopts the ordinance amendment revised according to the listed conditions.
2. Email the completed Ordinance Processing Checklist (attached) and the documents identified on
the checklist within 10 days of city council adoption to:
a. Taylor Huinker (taylor.huinker@state.mn.us)
b. Ordinance.review.dnr@state.mn.us
3. We will review the ordinance amendment adopted by the city council for consistency with the
above conditions and the terms of implementation flexibility.
4. If the adopted amendments are consistent with the conditions and terms of implementation
flexibility, I will send you a “final approval” letter. State rules require DNR final approval of
shoreland ordinances and amendments for those ordinances to be effective.
A shoreland ordinance is an important land use regulation that helps to protect surface water quality,
near shore habitat, and shoreland aesthetics of Minnesota’s public waters. We appreciate your efforts
to protect these resources for all present and future Minnesotans. Taylor Huinker is available to assist
with ordinance technical guidance and to consult with you on other land and water-related projects.
Sincerely,
Megan Moore
EWR Region 3 South District Manager
Attachments:
Proposed Ordinance with DNR comments
Ordinance Processing Checklist
c: Taylor Huinker, DNR Area Hydrologist
Ordinance.review.dnr@state.mn.us
23
1
CITY OF CHANHASSEN
CARVER AND HENNEPIN COUNTIES, MINNESOTA
ORDINANCE NO. XXX
AN ORDINANCE AMENDING CHAPTER 20
CHANHASSEN CITY CODE,
THE CITY COUNCIL OF THE CITY OF CHANHASSEN, MINNESOTA ORDAINS:
Section 1. Section 20-485 of the City Code, City of Chanhassen, Minnesota, is hereby
amended to read as follows with the underlined language to be added and the crossed out
language to be removed:
Sec 20-485 Stormwater Management:
Lot coverage of lots shall not exceed 25 percent of the lot area, except as follows:
a) 30 percent impervious shall be allowed for lots zoned Residential Single Family
(RSF) which were platted prior to January 1, 1976 with the following conditions:
1) Riparian Lots
a. When exceeding 25% impervious coverage, riparian lots shall be
required to have a shoreline vegetative buffer area equal in size to the
new impervious area proposed over 25% of the lot area. (Example:
100sf of impervious area will require 100sf of shoreline vegetative
buffer area).
1. The shoreline vegetative buffer will be required to encompass
at least 25% or 20 feet of the linear water frontage, whichever
is greater. The buffer width shall be the width necessary to
achieve the required buffer area. (Example, 100sf of
impervious area required with 25’ of buffer length along the
shoreline would require a vegetative buffer width of 4’.)
2. If the vegetative buffer required is determined to be infeasible
by the City Engineer, alternative BMPs shall be installed as
outlined in section B.
3. Access to the lake for swimming or dock use shall be
maintained.
4. The vegetative buffer may satisfy the Best Management
Practice (BMP) requirement outlined below.
b. The following shall be provided at the time of permit application:
1. Pre and post project lot cover calculations.
2. Water Quality Volume shall be calculated by 1.1 inch
multiplied by the area in square feet of impervious area over
25%.
3. BMPs shall be designed to treat the calculated amount of Water
Quality Volume created by the proposed impervious area.
24
2
4. Project plans on a scaled survey shall show the proposed
impervious surface as well as the offsetting location and design
of (BMPs). This could include native vegetative buffers, rain
gardens, rain barrels, infiltration/biofiltration basins/swales,
etc.)
5. An erosion and sediment control plan in accordance with
Section 19-145 of city code.
6. Additional information such as Hydrologic and Hydraulic
Modeling, plans certified by a professional engineer, etc. may
be required as determined by the City Engineer when there is
reasonable cause for concern of the impacts by the increased
stormwater runoff.
c. Changes in stormwater runoff shall not cause adverse impacts to
adjacent and downstream infrastructure.
d. BMPs installed shall be privately owned and may require an
Operations and Maintenance Agreement to be recorded against the
property at this discretion of the City Engineer.
e. Vegetative buffer areas shall be protected in an easement recorded
against the property and monuments shall be installed at the easement
boundary.
2) Non-Riparian Lots
a) The following shall be provided at the time of permit application:
1. Pre and post project lot cover calculations.
2. Water Quality Volume shall be calculated by 1.1 inch
multiplied by the area in square feet of impervious area
over 25%.
3. BMPs shall be designed to treat the calculated amount of
Water Quality Volume created by the proposed impervious
area.
4. Project plans on a scaled survey shall show the proposed
impervious surface as well as the offsetting location and
design of (BMPs). This could include native vegetative
buffers, rain gardens, rain barrels, infiltration/biofiltration
basins/swales, etc.
5. An erosion and sediment control plan in accordance with
Section 19-145 of city code.
6. Additional information such as Hydrologic and Hydraulic
Modeling, plans certified by a professional engineer, etc.
may be required as determined by the City Engineer when
there is reasonable cause for concern of the impacts by the
increased stormwater runoff.
b) Changes in stormwater runoff shall not cause adverse impacts to
adjacent and downstream infrastructure.
25
3
c) BMPs installed shall be privately owned and may require an
Operations and Maintenance Agreement to be recorded against the
property.
b) 35 Thirty-five percent for medium/high density residential zones; and
c) 70 Seventy percent in industrial zones within the Lake Susan Shoreland District.
Section 2. This ordinance shall be effective immediately upon its passage and
publication.
PASSED AND ADOPTED this ___day of _____, 2024, by the City Council of
the City of Chanhassen, Minnesota
______________________________ ________________________________
Kim Meuwissen, City Clerk Elise Ryan, Mayor
(Published in the Chanhassen Villager on ______________________________)
26
ORDINANCE PROCESSING CHECKLIST
Please complete, sign and return this checklist and all required documents by email to the
DNR:
Ordinance.review.dnr@state.mn.us, and
your Area Hydrologist
1. _______________ Date(s) of published public hearing notice(s). Email the notice
with this checklist.
_______________
2. _______________ Date(s) of public hearing(s).
_______________
3. _______________ Date of ordinance adoption. Email the adopted ordinance/
amendment with the signature of the chief elected official in
PDF format with this checklist.
4. _______________ Date of newspaper publication of adopted ordinance/
amendment or ordinance amendment summary.
5. Email a zoning map showing the “district” corresponding to the adopted ordinance
at the time of adoption, if one exists, and the underlying zoning districts if the
adopted ordinance refers to them.
_______________________________________________
Signature of Clerk/Auditor
_______________________________________________
Name of Community
27
28
29
SITE # PROJECT FILE NO.
DESIGN
STANDARD LOT COVER LISTED DETAILS NOTES
1 Minnewashta Creek 75-1 SUB Design Standard Y 25%
2 Red Cedar Cove Townhouses 85-5 PUD Design Standard Y 25%
Can be averaged throughout the entire
development
3 Ches Mar Farm & Trail 84-2, 88-1, 91-1 PUD Design Standard N
4a Meadows at Longacres 92-4 PUD Design Standard Y 25%
4b Woods at Longacres 93-3 PUD Design Standard Y 25%
5 Highlands at Bluff Creek 2003-3 PUD Design Standard Y 30%
6 Arboretum Village 99-2 PUD Design Standard Y 70% commercial / 30% total
site
7 Pheasant Hills 83-1 PUD Design Standard Y 30%
8 The Park 2019-01 PUD Design Standard Y 36.7% for 90 ft lots / 52% for
65 ft lots
Preserved 50 acres of woods adjacent
top Lake Ann
9 Walnut Grove 96-04 PUD Design Standard Y 30%
10 WillowRidge 91-3 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
11 Chaparral 78-01, 79-3 PUD Design Standard Y 30%
Can be averaged throughout the entire
development
12 Triple Crown Estates 85-2 PUD Design Standard Y 30%
13 Chanhassen Vista 86-1 PUD Design Standard Y 30%
14 Saratoga 1st and 2nd Additions 77-1 PUD Design Standard Y 30%
Can be averaged throughout the entire
development
15 Saratoga 3rd Addition 98-2 PUD Design Standard Y 65% Multi-family residential
16 Western Hills 79-6 PUD Design Standard Y 30%
17 Laredo Lane 75-2 PUD Design Standard Y 30%
18 Oak Ponds 92-3 PUD Design Standard Y 50% Multi-family residential
19 Near Mountain 79-2 PUD Design Standard Y 25% / 25% / 30% / 30% Varies based on housing types
20 Fox Hollow 84-1 PUD Design Standard Y 25%
Can be averaged throughout the entire
development
21 South Lotus Lake 85-4 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
22 South Lotus Villas 89-4 SPR Design Standard Y 54% High-density residential
23 Townhomes at Creekside 96-3 PUD Design Standard Y 30%
Averaged from the entire development,
including the public and private streets
and Outlots, may not exceed 30
percent hard coverage. Individual lots
will exceed the 30 percent site
coverage.
24 Trotters Ridge 93-2 PUD Design Standard Y 30%
25 Lynmore Addition 98-1 PUD Design Standard Y 30%
26 Autumn Ridge Townhouses 93-5 PUD Design Standard Y 30%
Averaged from the entire development,
including the public and private streets
and Outlots, may not exceed 30
percent hard coverage. Individual lots
will exceed the 30 percent site
coverage.
27 Lake Susan Hills 87-3 PUD Design Standard N Includes RSF, R-8, and R-12/16
28 Chanhassen Hills 85-6 PUD Design Standard Y 25%
29 West Park 2017-12 PUD Design Standard Y 50% RSF and Mixed Use
30 Chanhassen Gateway 2006-05 PUD Design Standard Y 50% Residential / 70%
Commercial and Office
31 Hidden Valley 85-1 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
32 Mission Hills 93-4 PUD Design Standard N
33 Preserve at Rice Lake 2013-12 PUD Design Standard Y 30%
34 Southwest Village 2006-18 PUD Design Standard Y 50% / 70% Commercial and
Transit Facility
35 North Bay 95-1 PUD Design Standard Y 50%
The entire development, including the
public and private streets and Outlots,
may not exceed 50
percent hard coverage. Individual lots
will exceed the 50 percent site
coverage. (Townhomes)
36 Lakeside 2006-26 PUD Design Standard Y 50%
The entire development, including the
public and private streets and Outlots,
may not exceed 50
percent hard coverage. Individual lots
will exceed the 50 percent site
coverage. (Twinhomes, townhomes,
and condos)
37 Springfield 1993-06 PUD Design Standard Y 25% in Shoreland / 30%
Elsewhere
38 Arbor Glen 2015-16 PUD Design Standard Y 59% Residential
The entire development, including the
private street and outlots, may not
exceed 25
percent hard coverage.
39 Preserve at Bluff Creek 2006-14 PUD Design Standard Y 45% Residential
The entire development, including the
public and private streets and Outlots,
may not
exceed 30 percent hard coverage.
Individual lots will exceed the 30
percent site coverage.
40 Liberty on Bluff Creek 2005-11 PUD Design Standard Y 30% Averaged from the entire development.
41 Camden Ridge 2013-13 PUD Design Standard Y 25% Shoreland / 35% Total
The entire development, including the
public and private streets and Outlots,
may not exceed 35
percent hard coverage. Individual lots
may exceed the 35 percent site
coverage. Lots within the
shoreland district may not exceed 25
percent site coverage.
42 Lake Lucy Island 2020-23 PUD Design Standard Y 25%
30
Memorandum
To:Eric Maass, Planning Director
From:Joe Seidl, Water Resources Engineer
CC: Charles Howley, Public Works Director/City Engineer
George Bender, Assistant City Engineer
Erik Henricksen, Project Engineer
Date:1/10/2024
Re:Amending Lot Cover Standards within the Shoreland Overlay
District and the Residential Single Family Zoning District
Introduction
The City of Chanhassen is considering increasing the maximum amount of lot cover allowed
from 25% to 30% within both the Shoreland Overlay District and the Residential Single Family
Zoning District. The Water Resources Division does not support the ordinance amendments to
increase lot cover. Water Resources staff believe that the increase in lot cover without the
construction of offsetting Best Management Practices (BMPs) has the potential to cause
adverse impacts. Lot cover or impermeable surfaces caused by urbanization and the
construction of buildings, pavement, etc. can have several negative effects on downstream
lakes, streams, and wetlands and the overall environment. Water Resources and Planning staff
have however worked successfully with the DNR to incorporate strategies related to the
Shoreland Overlay District that help mitigate potential effects.
The potential effects can include:
Increased runoff: Lot cover prevents rainwater from infiltrating into the ground and/or
uptake by vegetation (trees and shrubs) . Instead, the water flows over the surface and
increases the volume and velocity (rate) of the runoff; which can cause flooding and
erosion in nearby streams and rivers, and could overwhelm existing downstream storm
sewer collection and treatment systems, especially if those systems are already
undersized due to elevated rainfall amounts and intensity.
31
Reduced infiltration: When rainwater cannot penetrate the soil, it cannot recharge
groundwater supplies. This can lead to a decrease in the water table, which can cause
wells to run dry and streams to dry up.
Water quality degradation: As runoff flows over the land, it picks up pollutants such as
oil, fertilizers, and pesticides, and carries them into nearby waterways. This can lead to
decreased water quality and harm aquatic ecosystems and the organisms that depend
on them.
Increased temperature: Urban areas with increased lot cover tend to be hotter than
surrounding areas due to the absorption of heat by buildings and pavement. This can
lead to warmer water temperatures in streams and rivers, which can negatively impact
aquatic life.
The increase in stormwater volumes and runoff rates generated by impervious surfaces can
cause issues if not mitigated by the construction of stormwater Best Management Practices
(BMPs).
The following sections provide background information to inform Chanhassen’s Planning
Commission and City Council.
What is a stormwater BMP?
Stormwater Best Management Practices (BMPs) are a set of techniques and practices designed
to manage and treat stormwater runoff, which is rainwater and other precipitation that flows
over the ground and into storm drains or other bodies of water. Stormwater BMPs are designed
to reduce the negative impacts of stormwater runoff, such as flooding, erosion, and pollution
generated by impervious surfaces.
Overall, stormwater BMPs work by mimicking natural systems and processes to manage and
treat stormwater runoff by facilitating infiltration, filtration, settling, and evapotranspiration.
Commonly used stormwater BMPs include infiltration basins, biofiltration basins, wet ponds,
rain gardens, green roofs, and permeable pavers.
Proposed Lot Cover Ordinance Amendment in the RSF Zoning District
The proposed Lot Cover Ordinance within the Residential Single Family Zoning District does not
have any provisions included that require the construction of offsetting BMPs. The ordinance
amendment would increase the maximum lot cover allowed within a property from 25% to
30%.
32
Proposed Lot Cover Ordinance Amendment in the Shoreland Overlay District
The proposed Lot Cover Ordinance within the Shoreland Overlay District would increase the
maximum lot cover allowed for a property from 25% to 30% and includes provisions that would
require the applicant to construct and maintain a BMP to offset the increase in impervious
surface constructed. For properties adjacent to water resources the BMP would be a natural
vegetative buffer sized as a 1 to 1 ratio to the impervious area over the 25% threshold. All other
properties would be required to construct a BMP with a design approved by Water Resources
staff. City Staff worked with the Department of Natural Resources Hydrologist to develop the
proposed ordinance. The ordinance would allow lot cover flexibility within the Shoreland
Overlay district and would help the DNR achieve their goal of naturalizing the shoreland. The
provisions include the creation of a maintenance declaration that would be recorded against
the property to ensure the stormwater treatment improvement would be protected.
How are impervious surfaces regulated?
The construction and reconstruction of impervious surfaces are regulated locally by the City of
Chanhassen and by local Watershed Districts, including the Riley Purgatory Bluff Creek
Watershed District (RPBCWD), Minnehaha Creek Watershed District (MCWD), Lower Minnesota
River Watershed District (LMRWD) and the Carver County Water Management Organization
(CCWMO). The Metropolitan Pollution Control Agency (MPCA) also regulates the construction
of impervious surfaces through the Municipal Separate Storm Sewer System (MS4) Permit and
National Discharge Elimination System Construction Stormwater (NPDES) Permit.
In general, when a project is proposed, the amount of impervious surface being constructed is
quantified and converted into a Water Quality Volume (WQV) by multiplying the new
impervious surface area by 1.1 inch. For example, a project creating 1 acre of new impervious
surface would be required to design BMPs to treat a WQV of:
1 Acre =43,560 Square Feet X 1.1 Inch/(12 Inch/Foot) = 3,993 Cubic Feet of Treatment Required
In this example, as part of the project design, the project proposers would implement BMPs to
treat the WQV and create Hydrologic and Hydraulic (H&H) Models to compare existing and
proposed conditions to ensure stormwater is managed properly and will not create adverse
impacts downstream.
The requirements for the construction of BMPs and H&H modeling are generally associated
with defined amounts of impervious surface. For example, the RPBCWD has a stormwater
33
treatment requirement trigger set to 5,000 square feet of impervious surface being
constructed. The typical residential improvements (patios, decks, additions, etc.) governed by
the proposed ordinance amendment would not trigger the threshold to mandate stormwater
treatment.
This gap in regulation creates a problem because the smaller individual projects might not
create visible issues, but the cumulative impact of many smaller projects would create
stormwater management problems.
Standard practice is to ensure subdivision development projects design BMPs for the maximum
lot cover allowed within the parcels generated. Any increase to the lot cover after the fact
would create additional stormwater volumes in excess to those accounted for in the original
design.
What are potential impacts that residents could experience?
The existing stormwater infrastructure within Chanhassen would still serve to offset some of
the impacts noted above, including flood mitigation and pollutant removal. However, the
infrastructure was not designed for the increased lot cover allowances proposed nor the
additional stormwater runoff that would be generated. In general, Chanhassen stormwater
infrastructure is undersized due to when it was designed, therefore the additional runoff
generated would act to further tax our drainage system. Over time, if unmitigated lot cover
were to increase, residents could experience some of the following impacts:
Increased pollutant loads in stormwater ponds and water resources, which would
degrade water quality and increase the frequency and scale of algae blooms.
Increased frequency and duration of street flooding and high water levels of stormwater
ponds and water resources.
Increased erosion of natural and manmade stormwater conveyance systems.
Increased frequency and duration of nuisance drainage issues, such as wet yards, sump
pump discharge, and standing water.
How would the stormwater BMP improvements be regulated and managed for the Shoreland
Overlay District?
City staff would ensure the natural vegetative buffer or stormwater BMP was sized correctly as
regulated by City Ordinance during review of the building permit. Template maintenance
agreements and buffer declarations are available and would be provided to project proposers.
34
After construction, the BMP would be added into the asset management database managed by
the City’s engineering department. City staff would need to expand the current program that
tracks and completes inspections on private BMPs to ensure the assets function as designed.
When problems are identified, City staff would work with residents to get the issues resolved.
Depending on the scale of the problem and the resident’s commitment to complete the work,
the amount of time it would take to resolve a specific problem could vary greatly.
How do other agencies view the Proposed Lot Cover Ordinance Amendments?
The proposed ordinance changes to increase lot cover were coordinated with the water
management organizations that regulate the City of Chanhassen, including the Minnesota
Department of Natural Resources (DNR), RPBCWD, MCWD, MRWD, and CCWMO. In general,
these agencies are opposed to regulations that would generate additional impervious surfaces
without the construction of corresponding BMPs to mitigate adverse impacts. Correspondence
and memos provided by the agencies are included in the agenda item packet.
What is the guidance from Chanhassen’s Local Stormwater Management Plan?
The Local Stormwater Management Plan adopted in December of 2018 is intended to provide
the City of Chanhassen with information and direction in the administration and
implementation of water resource management activities within the City during the period
2018-2027. It serves as a guide to projects, provides for effective allocation of resources, and
sets forth a funding plan for projects and programs over the next 5 to 10 years.
The Local Stormwater Management Plan includes goals and policies to help achieve those goals.
Included below are the most pertinent sections regarding the proposed Ordinance
Amendments that would increase maximum lot cover allowances:
Goal 1 reads: “Promote abstraction through infiltration, reuse and other methods where
practicable to do so to provide flood protection, ground water recharge and improved water
quality.”
Within Goal 1 the two most relevant polices to the proposed ordinance amendments are
outlined below:
Policy 1.4. Continue to stringently enforce lot coverage requirements set forth in City Code
and development contracts.
35
Policy 1.2. Require all development and redevelopment projects to demonstrate no net
increase in the annual runoff water volume discharged from the site compared
to pre-development conditions.
The proposed ordinance amendments within the RSF Zoning District are in direct conflict with
the goals and policies of the Local Surface Water Management Plan. Without offsetting BMPs,
the increased hardcover would act to inhibit infiltration, reduce flood protection and
groundwater recharge, and decrease water quality.
Goal 2 reads: “Achieve water quality standards in lakes, streams, and wetlands consistent
with their designated uses and established classifications.”
Within Goal 2 the policy outlined that is most relevant to the proposed ordinance amendment
that would increase the maximum Lot Cover allowance within the Shoreland Management
District is:
Policy 2.15 Maintain a shoreland ordinance consistent with DNR requirements and
recommendations to promote and encourage shoreland protection.
The proposed Lot Cover ordinance modifications were coordinated with the DNR and received
conditional approval from the local area Hydrologist. While in general increases in lot cover are
not supported by the DNR, the ordinance changes within the Shoreland Overlay District and the
regulations that mandate the creation of natural vegetative buffers and stormwater BMPs are
viewed as a reasonable trade to allow Chanhassen residents flexibility for improvements on
their property that would increase lot cover. Therefore, the proposed ordinance changes within
the Shoreland overlay district are consistent with Policy 2.15.
It must be noted that water quality within large portions of the City of Chanhassen is below
standards set by the MPCA. Several of the local lakes and streams are on the impaired waters
list and therefore Chanhassen is not achieving Goal 2 of the Local Surface Water Management
Plan. The proposed Ordinance amendments within the Shoreland Overlay District do not apply
to reconstructed impervious surfaces and therefore only act to preserve the current state of
the local water resources.
The Water Resources Department recommends that the ordinance proposed be amended to
include BMP requirements for reconstructed impervious areas to improve the quality and
character of receiving water bodies as redevelopment occurs.
36
Planning Commission Item
January 16, 2024
Item Approve Planning Commission Meeting Minutes dated December 5, 2023
File No.Item No: D.1
Agenda Section APPROVAL OF MINUTES
Prepared By Jenny Potter, Sr. Admin Support Specialist
Applicant
Present Zoning
Land Use
Acerage
Density
Applicable
Regulations
SUGGESTED ACTION
"The Chanhassen Planning Commission approves its December 5, 2023 meeting minutes"
SUMMARY
BACKGROUND
DISCUSSION
RECOMMENDATION
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ATTACHMENTS
Planning Commission Minutes dated December 5, 2023
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CHANHASSEN PLANNING COMMISSION
REGULAR MEETING
MINUTES
DECEMBER 5, 2023
CALL TO ORDER:
Chairman Noyes called the meeting to order at 6:00 p.m.
MEMBERS PRESENT: Chair Eric Noyes, Erik Johnson, Kelsey Alto, Perry Schwartz, Ryan
Soller, Edward Goff, Steve Jobe.
MEMBERS ABSENT: None.
STAFF PRESENT: Rachel Arsenault, Associate Planner; Rachel Jeske, Planning Intern; Eric
Maass, Planning Director; Laurie Hokkanen, City Manager, Joe Seidl, Water Resources
Engineer
PUBLIC PRESENT:
Mark Undestad Eden Trace Corporation, 8821 Sunset Trail, Chanhassen MN, 55317
PUBLIC HEARINGS:
1. AFFINITECH SITE PLAN REVIEW – 2451 GALPIN COURT
Rachel Arsenault, Associate Planner, presented an overview of the Affinitech site plan.
Commissioner Schwartz asked if the architecture plans submitted match the elements of nearby
properties. Ms. Arsenault stated the materials are limited in the development by the planned unit
development standards so many elements are similar.
Chair Noyes opened the public hearing. There were no public comments.
Chair Noyes closed the public hearing.
Chair Noyes shared the elements for the landscaping and architecture are appropriate for this
area of the city, so he had no concerns. He invited the applicant to come and share comments.
The applicant shared this is the last unit to be developed in this area. They are excited to keep
Affinitech as a tenant and provide a permanent home for them in Chanhassen. He thanked staff
for completing the reports.
Vice-Chair Alto moved, Commissioner Jobe seconded that the Chanhassen Planning
Commission recommend approval of the proposed site plan located at 2451 Galpin Court
in the Chanhassen West Business Park, subject to the conditions outlined in the city staff
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report and water resources reports and adopts the findings of the fact and decision. All
voted in favor and the motion carried unanimously with a vote of 7 to 0.
APPROVAL OF MINUTES:
1. APPROVAL OF PLANNING COMMISSION MINUTES NOVEMBER 6, 2023
Commissioner Goff moved, Commissioner Schwartz seconded to approve the Chanhassen
Planning Commission summary minutes dated November 6, 2023 as presented. All voted in
favor, and the motion carried unanimously with a vote of 7 to 0.
COMMISSION PRESENTATIONS: None.
ADMINISTRATIVE PRESENTATIONS:
1. DISCUSSION ON MAXIMUM LOT COVER PRECENTAGE IN RESIDENTIAL
SINGLE FAMILY (RSF) DISTRICT AND SHORELAND OVERLAY ZONING
DISTRICT
Laurie Hokkanen, City Manager, shared that the City Council has looked at hard cover lot
requirements in City Code in working sessions. The City Council set policy direction to increase
lot cover to 30 percent in residential and shoreland overlay districts as much as possible. Ms.
Hokkanen stated there are exceptions, including planned unit developments. The Department of
Natural Resources have made modifications and adjustments for the proposal for the shoreland
overlay district lot cover.
Eric Maass, Planning Director, shared the Minnesota Department of Natural Resources has
jurisdiction and needs to approve changes. City staff met with the Department of Natural
Resources who would prefer vegetative buffer along the shoreline and made suggested changes
to the current language provided in the packet.
Chair Noyes asked what was driving the review of the hard cover lot requirements. Ms.
Hokkanen shared the review is based on the requests from property owners. The City Council
and Planning Commission rarely approve variance requests. There has been an increase in
variance requests which has encouraged the City Council to evaluate current rules.
Commissioner Schwartz asked for additional information of the vegetative buffers. Mr. Maass
responded the best management practice would be offsetting activity for increased perviousness.
The Department of Natural Resources wants to see a one-to-one ratio between the lot cover and
vegetative buffers to offset increased runoff.
Commissioner Schwartz questioned flexibility in the ordinance if a lot line is not straight. Mr.
Maass shared the language from the ordinance. The width should not encompass more than 50
percent of the current shoreline, but they are trying to provide flexibility for residents to meet the
required square footage.
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Vice-Chair Alto asked about the long-term impact on the lakes would be if there was 30 percent
lot cover on all the properties. Mr. Maass stated many residents do not meet the current limit for
lot cover and thinks there would only be a handful of projects in a year that would exceed 25
percent of lot cover.
Vice-Chair Alto encouraged the staff to consider the long-term impacts on nature. She stated
other cities might make decisions based on lake home ownership rather than what is best for the
community and nature.
Mr. Maass shared the Department of Natural Resources is providing flexibility to lots created
prior to January 1, 1976.
Vice-Chair Alto asked what percentage of the lots fell into that category. Mr. Maass answered
there approximately 60 percent of lots were created prior to January 1, 1976 and 40 percent of
lots were created after January 1, 1976.
Commissioner Schwartz agreed with Vice-Chair Alto. He shared the value of vegetative buffer is
clear and he is concerned they are not considering best management practices to deal with runoff
of lots going into the water.
Mr. Maass clarified if an individual wants additional lot cover, they need to provide a vegetative
buffer.
Vice-Chair Alto asked about maintenance enforcement throughout the homeownership. Mr.
Mass shared the vegetative buffer would require an easement to be recorded, posts to be placed
at the corners, and an operation and maintenance agreement to be established to ensure the long-
term function.
Vice-Chair Alto questioned whether there would be a fine if property owners do not comply. Mr.
Maass shared they are considering a monitoring program to ensure the vegetative buffers exist
and are functioning.
Vice-Chair Alto shared her concerns that if the only punishment was a fine, property owners
would opt to pay the fine rather than comply with the requirements.
Commissioner Goff asked if a homeowner did not want to comply with the requirements if a
homeowner could request a variance.
Mr. Maass shared a property owner could apply but they could not receive a variance around a
process.
Commissioner Goff stated there are many odd-sized lots around the lake which has provided the
need for variances. He asked if these requirements are meant to eliminate the need to request
variances with the Planning Commission.
Mr. Maass shared a property owner would possibly need to request a variance for certain
reconstruction. The proposed ordinance is for existing homes looking to add additional lot cover.
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Chair Noyes shared his concern regarding these requirements, providing an example that if a
property owner was reconstructing and using the maximum lot cover percentage, it might require
additional variances, such as side yard setback.
Commissioner Soller asked for a timeline to remind the Commission of the history leading up to
this discussion.
Ms. Hokkanen shared it started in February with the Planning Commission based on an analysis
of the variance requests. In July, the Planning Commission received a proposal for the Shoreland
Overlay District to use pervious pavers for five percent lot cover. Commissioner Soller
confirmed that there is a public hearing January 16th and that this is a proposed ordinance. If
there is a vote that does not pass with the Planning Commission, it is a recommendation against
the ordinance to the City Council.
Chair Noyes asked if there would be a possibility to separate the Shoreland Overlay District and
the residential single-family district would be separate voting matters on January 16.
Mr. Maass confirmed this information.
Commissioner Schwartz asked why there was an interest in pervious pavers, as over time they
become impervious.
Ms. Hokkanen stated this is a City Council driven issue and introduces additional options along
with pervious pavers for lot cover, such as rain gardens or rain barrels.
2. CIVIC CAMPUS PROJECT UPDATE
Laurie Hokkanen, City Manager, shared an overview of the Civic Campus Project Update. There
will be an open house next Tuesday, December 12, from 4 to 6 PM in the Senior Center. She
reviewed the locations and uses of the buildings and discussed the complimentary architectural
materials implemented throughout the Civic Campus.
Commissioner Schwartz asked about ADA compliance and ramps near the pavilion. Ms.
Hokkanen shared that there are ADA options to access every route. She shared there is
consideration to implement an elevator, but this is budget dependent. They have received
multiple price quotes on the elevator and are trying to clarify the costs.
Commissioner Schwartz asked about trees throughout the site. Ms. Hokkanen shared there are
high priority areas where they will invest in more mature trees, and they are prioritizing pockets
for greenery.
Commissioner Schwartz encouraged consideration of lighting in the bandshell for the
performers. He also asked if the furniture would be secured so individuals cannot walk away
with the furniture.
Ms. Hokkanen shared this information is not yet finalized.
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Vice-Chair Alto asked where the farmer’s market would be located. Ms. Hokkanen reviewed
options for the location, including the main parking lot or the green space. They are including
power options in both places for the farmer’s market or food trucks.
Commissioner Jobe questioned if there would be security cameras and asked if there would be a
staff member who would oversee the rentals of spaces and equipment. Ms. Hokkanen shared
they do not envision there being a full-time manager for this site. She shared outdoor yard games
are popular parks and they will continue to investigate options for equipment use. She confirmed
there would be security cameras.
Commissioner Soller asked if this space would be subject to traditional park closing times and if
the fireplace areas would be gas and push-button operated. He asked if there would be a
possibility to expand public Wi-Fi options so individuals can use the seating to work. He shared
newer playgrounds are often geared towards children with different types of abilities and asked if
this playground would fall into this category.
Ms. Hokkanen shared the playground would not be the top option for accessibility due to space
constraints. She confirmed the fire pits would be open to public use before the 10 PM park
closing. She answered the Wi-Fi options are budget dependent, but they are considering these
options.
Commissioner Soller asked how close these images are to the final design and wondered about a
targeted grand opening. Ms. Hokkanen shared they are close. They are having a construction
manager look through the plans prior to opening the plans to bid. She said they are currently in
the cost estimate phase. There is a goal to complete the plan by July 2025.
Commissioner Schwartz questioned how the project is being funded. Ms. Hokkanen answered
the project is being funded by levy-dollars and they are issuing general obligation debt for the
project. There will be a 6.5 to 7 percent levy increase over the course of multiple years.
Commissioner Schwartz shared concerns about rollerbladers, families walking, and strollers
using the same concrete walk and encouraged city staff to take these concerns into consideration.
Eric Maass, Planning Director, communicated that Xcel Energy is reviewing the plans to ensure
the building is energy efficient and meets rebate options.
Commissioner Schwartz asked if there were plans for solar panels.
Ms. Hokkanen shared the building would be solar-ready and installation would be dependent on
budget. There would also be sections for car-charging dependent upon budget.
CORRESPONDENCE DISCUSSION:
Planning Director Maass updated the Commissioners, noting that Bob Generous would be
retiring in January 2024. He celebrated 30 years with the City in September 2023.
ADJOURNMENT:
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Commissioner Jobe moved, Vice-Chair Alto seconded to adjourn the meeting. All voted in
favor and the motion carried unanimously with a vote of 7 to 0. The Planning Commission
meeting was adjourned at 7:12 p.m.
Submitted by Eric Maass
Planning Director
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