12. preliminary cc approvalOn July10, 2017, the Chanhassen City Council adopted the following motion:
Request for Preliminary Plat creating 17 lots, 3 outlots and dedication of public right-of-way for
public streets (115.519 acres); and a Rezoning of 115.519 acres of property zoned Agricultural
Estate District, A2, to Planned Unit Development-Regional Commercial District (PUD-RC)
including Exhibit A Avienda Design Standards; and Conditional Use Permit to encroach into the
primary zone and required buffer for development in the Bluff Creek Corridor; Wetland Alteration
Permit to 4.897 acres of permanent wetland impacts as shown in plans dated April 14, 2017, and
June 13, 2017, to request to construct into the primary zone and required buffer for development in
the Bluff Creek Corridor located at the southwest corner of Powers Boulevard and Lyman
Boulevard.
WETLAND ALERATION PERMIT
The City Council approved the Wetland Alteration Permit to 4.4659 acres of permanent wetland
impacts subject to conditions:
• The applicant needs to supply the needed additional information to the city. The additional
information is needed to determine if the project meets the WCA requirements.
• A Technical Evaluation Panel meeting is needed to review the application.
• If the application is deemed to meet the avoidance and minimization criteria of the WCA, a
mitigation plan that adequately replaces wetland functions and values is needed.
• City Staff has reviewed mitigation options. City Staff recommends the applicant provide
wetland mitigation via the purchase of wetland bank credits, at a ratio of 2:1, in accordance
with WCA requirements.
• The applicant shall contribute $300,000 to the city for water quality improvement projects
within the watershed.
Wetland Functions and Mitigation
If the project meets the WCA sequencing and shows that the wetland impacts need to occur for
the project (i.e. if the project meets wetland avoidance and minimization requirements), the rest
of the WCA review for this project is dependent on wetland replacement.
The WCA requires that wetland replacement must replace the public value of wetlands lost
because of an impact. The public value of wetlands is generally based on the functions of
wetlands including: water quality, flood water attenuation, public recreation and education, and
fish/wildlife/plant habitats. The WCA uses the Minnesota Routine Assessment Method
(MnRAM) to determine functions and values. The City completed a city-wide MnRAM in
2006. The applicant has completed MnRAM as part of the application process. For the on-site
wetlands that were previously evaluated by the City, the applicant’s MnRAM has either the same
result or a slightly higher quality results for the wetlands.
The table above shows the wetland management categories from the application. The standard
categories that the City uses, which are in conformance with state guidance, is as follows:
• Preserve: These are the highest quality wetlands and have high quality habitat and native
vegetative diversity.
• Manage 1: These are a lower quality than Preserve, but still show high habitat quality
and plant diversity.
• Manage 2: These wetlands have been impacted by stormwater, invasive species, or other
impacts and are lower quality than Manage 1. They likely still provide some habitat and
may have some native plant species.
• Manage 3: These wetlands have been impacted the most and may provide a stormwater
treatment function and have minimal native plants. These are the lowest quality
wetlands.
The wetlands proposed to be impacted by the project are either Manage 2 or Manage 3
wetlands. Some have historically been excavated. These wetlands do not contain a diversity of
native plants. They do provide stormwater and floodplain treatment for downstream wetlands as
they are at the headwaters of the Bluff Creek and Lake Susan watersheds. Downstream waters
are impaired for water quality.
Wetland mitigation that replaces wetland functions and values at a minimum of a 2:1 ratio is
required and can be met in a variety of ways:
• On-site mitigation: New wetlands are created or restored within a project area. This
could address replacing functions and values in the same area, but the current layout does
not provide opportunity for a reasonable creation or restoration project. Also, creating
new wetlands takes time and there are many factors to consider for its success.
• Replacement in the same subwatershed: New wetlands are created or restored within the
same minor or major subwatershed as the project. This would allow wetland functions
and values to be replaced within the subwatershed where the project is located and the
project layout would not have to be altered to fit mitigation on site. However, a suitable
site would need to be located.
• Purchase of wetland credits from a wetland bank: There are several wetland banks in the
state and applicants can purchase credit from these already created wetland areas. It is
preferred in the WCA rules that a bank within the same bank service area be chosen to
purchase credit for a project.
• Some combination of these mitigation options: An eligible project can also use a
combination of these mitigation options.
As stated, if the project is determined to have met the avoidance and minimization criteria for the
wetland impact, wetland mitigation for the lost functions and values would be required at a
minimum of a 2:1 ratio. Currently, the applicant is proposing mitigation through the purchase of
credit from three wetland banks in Blue Earth, Stevens, and Rice Counties. These banks are in
the same bank service area, and only one is in the same major watershed area.
• In addition to the wetland bank credits, City staff recommends that a condition of
approval will include that the applicant shall contribute $300,000 to the City for water
quality improvement projects within the watershed.