PC staff report west water treatmentCITY OF CHANHASSEN
PC DATE: September 6, 2016
CC DATE: September 26, 2016
REVIEW DEADLINE: October 4, 2016
CASE #: 2016-21
BY: RG, TJ, ML, JM, JS, SS
SUMMARY OF REQUEST: Request for a Site Plan Review and replat of Lot 1, Block 4, and
Outlot A of Lake Harrison to construct the West Water Treatment Plant.
LOCATION: 2070 Lake Harrison Road (Lot 1, Block 4, and Outlot A, Lake Harrison)
APPLICANT: Greg Johnson, P.E. Paul Oehme, P.E., Public Works Director
WSB & Associates City of Chanhassen
477 Temperance Street 7700 Market Boulevard
St. Paul, MN 55101 P. O. Box 147
(651) 286-8466 Chanhassen, MN 55317
gjohnson@wsbeng.com (952) 227-1169
poehme@ci.chanhassen.mn.us
PRESENT ZONING: Single-Family Residential, RSF
2020 LAND USE PLAN: Parks and Open Space
ACREAGE: 6.57 acres DENSITY: 0.06 F.A.R.
PROPOSED MOTION:
“The Chanhassen Planning Commission recommends approval of the subdivision creating one lot
and two outlots and site plan for a 16,950 water treatment facility subject to the conditions of
approval and adoption of the findings of facts and recommendation.”
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 2 of 11
LEVEL OF CITY DISCRETION IN DECISION-MAKING:
The city’s discretion in approving or denying a Preliminary Plat is limited to whether or not the
proposed plat meets the standards outlined in the Subdivision Regulations and Zoning
Ordinance. If it meets these standards, the city must approve the preliminary plat. This is a
quasi-judicial decision.
The city’s discretion in approving or denying a Site Plan is limited to whether or not the
proposed project complies with Zoning Ordinance requirements. If it meets these standards, the
city must then approve the site plan. This is a quasi-judicial decision.
Notice of this public hearing has been mailed to all property owners within 500 feet.
PROPOSAL/SUMMARY
Request for subdivision approval to replat Lot 1, Block 4, Lake Harrison and Outlot A, Lake
Harrison into one lot and two Outlots and site plan review for a 16,950 square foot water
treatment facility.
APPLICABLE REGULATIONS
Chapter 18, Subdivision
Chapter 20, Article II, Division 6, Site Plan Review
Chapter 20, Article VI, Wetland Protection
Chapter 20, Article XII, “RSF” Single-Family Residential District
Chapter 20, Article XXIII, Division 7, Design Standards for Commercial, Industrial and Office-
Institutional Developments
BACKGROUND
The plat for Lake Harrison was approved on July 12, 2005 as Planning Case #2005-14 creating 39
lots, 6 outlots and associated right-of-way for public streets with a variance for a private street and
street grade. As part of the development, the City purchased Lot 1, Block 4, in the northeast
portion of the site for a future water treatment plant. In addition, a raw water main was extended
through the development from the well fields to the north and west in anticipation of the
construction of the water treatment plant.
On May 9, 2005, the Chanhassen City Council approved: Rezoning of the property from RR, Rural
Residential, to RSF, Single Family Residential District; Preliminary plat (Subdivision) to create 40
lots, 4 outlots and public right-of-way with a variance for a private street and street grade; a 5-foot
front yard Variance for Block 2; a Wetland Alteration Permit to fill and alter wetlands on site;
and denied the bluff setback variance.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 3 of 11
PRELIMINARY PLAT
The city is proposing the replat of Outlot A and Lot 1, Block 4, Lake Harrison into one lot for the
water treatment facility and park area and two outlots containing open space and wetlands. The
lot shall be developed with a water treatment facility and a neighborhood park. Manchester
Drive will be extended to provide a permanent cul-de-sac and parking area for the neighborhood
park. The outlots shall contain wetlands and permanent open space. Public streets, water and
sewer were provided as part of the Lake Harrison development.
EASEMENTS
The site plan requires replatting Lot 1, Block 4 and Outlot A, Lake Harrison, therefore the
existing drainage and utility easements on these properties must be vacated prior to recording the
final plat.
COMPLIANCE TABLE
Area (sq.
ft.)
Width
(ft.)
Depth
(ft.)
Hard Cover
% / sq. ft.
Notes
Code 15,000 90 125 25 / 3,750
Lot 1 179,858 245 44,964 4.13 acres
Outot A 45,411 1.04 acres, Contains wetlands
(eastern outlot)
Outlot B 21,718 0.5 acres, contains wetlands and
slope (western outlot)
Total 246,987 5.67 acres
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 4 of 11
SITE PLAN REVIEW
The city is proposing a 16,950 water treatment facility with underground backwash tanks
northeast of the building. In the future, a neighborhood park is being proposed at the end of
Manchester Drive.
Access to the site will be via a 30-foot wide access off of Lake Harrison Road. The proposed
location exceeds the city’s minimum access spacing requirement from Galpin Boulevard. The
plan includes a paved area in front of the building to accommodate parking and delivery
vehicles. Curb and gutter are required around the parking area.
The plan includes installing a 90-foot diameter cul-de-sac at the end of Manchester Drive to
provide vehicular access and parking for future park amenities in the area. An 8-foot wide
bituminous trail is proposed to extend from the parking area; an ADA-compliant curb ramp must
be installed.
UTILITIES
Eight-inch lateral sanitary sewer will be extended from Galpin Boulevard to the site. A water
service will be stubbed to the building from the water system improvements that will be
installed.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 5 of 11
The Metropolitan Council Environmental Services Sewer Access Charge (Metro SAC) must be
paid with the building permit. The West Water Treatment Plant is not subject to the City Sewer
Access Charge and Water Access Charge (City SAC and WAC).
GRADING AND RETAINING WALLS
The site drops 30 feet in elevation from the north (Manchester Drive) to the south (Lake Harrison
Road). The water treatment plant is proposed to be built into the slope. Two, 30-foot long
retaining walls are proposed at the following locations:
1) At the northwest corner of the building, maximum height of four feet, and
2) At the southwest corner of the building, maximum height 19.5 feet.
The following comments must be incorporated into the final grading plan:
a) The bottom of wall elevation of the northerly retaining wall is mislabeled (shown as
914.0’, appears to be 1014.0’), and
b) The 984’ contour southwest of the parking area is mislabeled (shown as 884’).
SURFACE WATER MANAGEMENT
City code requires that a project either meets NURP recommendations or the National Pollution
Discharge Elimination System (NPDES) Requirements, whichever is more restrictive. As the
project will exceed the National Pollution Discharge Elimination System threshold for
permanent stormwater management the NPDES permit would be the more restrictive. This
requires a net reduction in runoff volume, total phosphorous and total suspended solids leaving
the site post-development.
This site will also be subject to the Riley Purgatory Bluff Creek Watershed District (RPBCWD)
Rule J – Stormwater Management. RPBCWD requires that applicant demonstrate that they can
accomplish the following goals:
1) Limit peak runoff from all points leaving the site to at or below the existing rates for the
2, 10 and 100-year return frequency storms.
2) Provide onsite abstraction for 1.1 inches of runoff from all impervious surfaces.
3) Provide, on an annual basis, removal of 60% total phosphorous and 90% total suspended
solids.
If the RPBCWD criteria are met, this will satisfy the city requirements for stormwater
management. A stormwater management plan, including a hydraulic and hydrologic model,
discussion of how the proposed best management practices will meet the volume requirements, a
water quality model (either P8 or MIDS Calculator), and Walker calculations demonstrating
adequate capacity within the existing and proposed conveyance system shall be submitted and
approved prior to issuance of any permits.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 6 of 11
The proposed inlet to the existing pond under the driveway (5003) will result in a short circuit
condition. This must be modified to maximize the separation and reduce the probability of short
circuiting.
The proposed inlet into the exiting pond from the proposed cul-de-sac is greater than 16%. This
has the potential to accelerate the runoff to the pond and exceed scour velocities. The pipe shall
be made shallower and the Walker calculations must demonstrate that scour velocities will not
occur at FES 5005.
EROSION PREVENTION AND SEDIMENT CONTROL
The project exceeds the NPDES permit threshold. The applicant shall prepare a Surface Water
Pollution Prevention Plan (SWPPP) and submit to the city for approval prior to the issuance of
any permits. No earth disturbing activities may occur until an approved SWPPP is developed.
This SWPPP shall be a standalone document consistent with the NPDES Construction Permit
and shall contain all required elements as listed in Parts III and IV of the permit.
SITE CONSTRAINTS
Wetland Protection
There exists onsite two wetlands. One wetland exists adjacent to Galpin Boulevard and includes
a mitigation area for wetland impacts that occurred with the Lake Harrison development. The
other is located at the western limits of the property and also includes a mitigation area. These
were delineated in 2008 and were reviewed by city staff this summer to verify that their
boundaries have not significantly changed. Any proposed disturbance will be a minimum of 200
feet from the western wetland basin. The easterly wetland is in relatively close proximity to the
proposed improvements. Although no impacts are likely to occur from the project, the site must
still accommodate the required buffer and setback. The plans should be updated to clearly
indicate the wetland boundary and the edge of buffer.
Shoreland Management District
The property is at least partially within the Shoreland Management District for Lake Harrison.
The site must meet the requirements for construction with the Shoreland Management District.
ARCHITECTURAL COMPLIANCE
The applicant is requesting site plan approval for a 16,950 square-foot water treatment facility.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 7 of 11
Size Portion Placement
The main entrance to the building is located on the south side of the building. The entrance is
covered by roof overhang that is raised up from the rest of the roof. The entrance is tucked into a
small entry stoop or porch type area. This facility is not intended for general visitor entry. A
ten-foot-tall berm is located to the south of the building adjacent to Lake Harrison Road which
will screen the parking area. An accessible ramp is located on the west side of the building.
Material, Detail and Color
The building materials are primarily a reddish-brown brick veneer with tan stone accent bands
and columns of cultured stone veneer. The roof material is a gray metal. A hardietrim trim
board and facial frame the roof and building interface as well as along the clerestory window
band. Precast stone cap stone provides a ledge for the clerestory window band
Height and Roof Design
Height is limited to three stories or 35 feet in the Single-Family Residential District. The
building has stepped roof heights as it moves up the hill with the highest roof peak 21 feet to the
top of roof above grade. The building uses prairie roof style with shallow pitches (12:3) and
large eves. On the west, north and east elevations of the northern part of the building and over
the southern entrance, a small dormer type roof treatment provides addition height and
architectural relief to the roof line and building.
Facade Transparency
This building is not intended for public view so minimal windows are necessary or advisable.
Clerestory spandrels windows are provided on all four elevations of the building with a few clear
windows to provide natural lighting within the building. Windows are provided at the
office/control room area of the building to the north of the main entrance. All other areas shall
include landscaping material and architectural detailing and articulation.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 8 of 11
Site Furnishing
The city is providing a trail connection from the park area above to the trail on Galpin
Boulevard. The upper area of the site will be developed as a neighborhood park.
Loading areas, refuse area, etc.
Loading areas are located on the southwest side of the building where the loading dock is
located, which is screened from public view by the building orientation, berming and
landscaping. No specific outdoor refuse area is proposed.
LANDSCAPING
Landscaping requirements for the West Water Treatment Plant include bufferyard plantings to
the north and foundation plantings around the building. Minimum landscaping requirements are
as follows.
Landscape Requirement Required plantings Proposed plantings
Bufferyard B – 240’ 3 overstory trees
5 understory trees
9 shrubs
3 overstory trees
13 understory trees
5 shrubs
The applicant exceeds quantities for understory trees but falls short for the quantity of shrubs.
The understory trees are evergreen that provide year round buffering. An increased number of
these plantings provide a better buffer than the shrubs. Staff recommends that the proposed
buffer plantings be accepted.
The applicant is proposing to preserve a number of existing trees on site and use foundation
plantings to break up expanses of the building, buffer site lines from various points and create an
aesthetically pleasing grounds. The locations of proposed landscape plantings will need to be
field located to work around existing trees. Proposed planting will be placed on site in locations
that do not conflict with preserved trees. All existing trees proposed to be preserved will be
required to have tree protection fencing installed at the driplines or a minimum of 15 feet from
the trunk.
MISCELLANEOUS
The building is required to have an automatic fire extinguishing system. Building plans must be
prepared and signed by design professionals licensed in the State of Minnesota. Retaining walls
over four high must be designed by a professional engineer and a permit must be obtained prior to
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 9 of 11
construction. Detailed occupancy related requirements will be addressed when complete building
plans are submitted. The owner and or their representative shall meet with the Inspections Division
as soon as possible to discuss plan review and permit procedures.
COMPLIANCE TABLE
RSF West Water Treatment Plant
Building Height 3 stories 1 story
35 feet 21 feet to roof peak
Building Setback N - 30' E - 10' N – 108’ E - 30'
W - 10' S - 30' W - 312' S – 144’
Wetland Setback: 20’ buffer 20’ buffer
Building 30’ to buffer 50’ to buffer
Parking 15’ to buffer 15’ to buffer
Parking Stalls 2 6
(One per employee plus one per vehicle normally parked on site.)
Parking Setback N - 30’ E - 10' N - 396' E - 72'
W - 10’ S - 30' W - 151' S - 120'
Hard Surface Coverage 25% 13%
Lot Area 0.344 acre 6.27 acres
RECOMMENDATION
Staff recommends that the Planning Commission approve the subdivision creating one lot and
two outlots and site plan for the water treatment facility subject to the following conditions:
SUBDIVISION
Existing drainage and utility easements on these properties must be vacated prior to recording the
final plat.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 10 of 11
SITE PLAN
Building
1. The building is required to have an automatic fire extinguishing system.
2. Building plans must be prepared and signed by design professionals licensed in the State of
Minnesota.
3. Retaining walls over four high must be designed by a professional engineer and a permit
must be obtained prior to construction.
4. Detailed occupancy related requirements will be addressed when complete building plans
are submitted.
5. The owner and or their representative shall meet with the Inspections Division as soon as
possible to discuss plan review and permit procedures.
Environmental Resources Specialist
1. All existing trees to be preserved shall have tree protection fencing installed at the
driplines or a minimum of 15 feet from the trunk, prior to any grading.
2. Proposed landscaping will be field located.
Engineering
1. The existing drainage and utility easements must be vacated prior to recording the final
plat.
2. Curb and gutter are required around the parking area.
3. An ADA-compliant curb ramp must be installed from the parking area at the Manchester
Drive cul-de-sac to the 8-foot wide trail.
4. The following comments must be incorporated into the final grading plan:
a) The bottom of wall elevation of the northerly retaining wall is mislabeled (shown as
914.0’, appears to be 1014.0’), and
b) The 984’ contour southwest of the parking area is mislabeled (shown as 884’).
5. The Metropolitan Council Environmental Services Sewer Access Charge (Metro SAC)
must be paid with the building permit.
6. The West Water Treatment Plant is not subject to the City Sewer Access Charge and
Water Access Charge (City SAC and WAC).
7. The applicant shall prepare a Surface Water Pollution Prevention Plan (SWPPP) and
submit to the city for approval prior to the issuance of any permits.
8. A stormwater management plan, including a hydraulic and hydrologic model, volume
reduction methods, a water quality model (either P8 or MIDS Calculator), and Walker
calculations demonstrating adequate capacity within the existing and proposed
conveyance system shall be submitted and approved prior to issuance of any permits.
9. The applicant shall submit and receive all applicable permits from the Riley Purgatory
Bluff Creek Watershed District prior to commencement of any work on the site.
Planning Commission
West Water Treatment Plant – Planning Case 2016-21
September 6, 2016
Page 11 of 11
10. The applicant shall submit and receive all applicable permits from the Minnesota
Pollution Control Agency prior to commencement of any work on the site.
11. The plans shall be modified to clearly demarcate the wetland boundary and the edge of
buffer.
12. A vegetation management plan shall be prepared and submitted for review and approval
prior to the issuance of a building permit.
13. The plan shall indicate placement of wetland buffer signs.
ATTACHMENTS
Findings of Fact and Recommendation
Development Review Application
Lot Split Sketch
Reduced Copy Lake Harrison Plat
WSB Project Narrative with Appendices A – D
Building Elevation North and West
Building Elevations East and South
Consortium of HOA’s Questions & Staff Responses dated August 22, 2016
Email messages from Xcel’s Jennifer Abbott & Kim Marinac re: Electric outages in the Lake
Harrison neighborhood
Public Hearing Notice and Mailing List
Jag Reddy Letter
Chlorine Plant Accidents List 1998-2013
WISE Phase 3 Water Utility Guidelines
Michelle Treptau Email
Consortium of HOA
Robert Kline Email
Email from Arjau K.
Chanhassen West Water Treatment Plant Open House Sign Up Form
West Water Treatment Plant Project – Open House Comments from Michelle Treptau
West Water Treatment Plant Landscape Plan
G:\PLAN\2016 Planning Cases\2016-21 West Water Treatment Plant\staff report west water treatment.doc