HomeMy WebLinkAbout2020-06-05 MSCWMO Review Letter & Approval Julie Hultman
From: Eric Johnson
Sent: Monday, June 15, 2020 10:15 AM
To: Mann, Lee; Julie Hultman
Subject: FW: MSCWMO Central Automotive Review Memo
Attachments: MSCWMO_Review_Letter._060520pdf.pdf
FYI
From: Rebecca Nestingen <RNestingen@mnwcd.org>
Sent: Monday, June 8, 2020 1:04 PM
To: Eric Johnson <eajohnson@cityofoakparkheights.com>; Adam Thiele<AThiele@ae-mn.com>
Cc: Matt Downing<MDowning@mnwcd.org>
Subject: MSCWMO Central Automotive Review Memo
Mr. Johnson,
Attached is the MSCWMO review letter for the proposed Central Automotive Project.The MSCWMO staff recommends
approval with conditions.
Rebecca Nestingen, PE I District Engineer
Washington Conservation District 1455 Hayward Ave N. I Oakdale, MN 55128
Office: (651) 330-8220 Ext. 21
Website: www.mnwcd.orq
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MIDDLE ST. CROIX WATERSHED MANAGEMENT ORGANIZATION
455 HAYWARD AVE . N , OAKDALE , MINNESTOA 5 51 28 w..t
Phone128 tZI Pathx22 fax 6 5 1 . 3 3 0 . 7 7 4 7 www . m s c w m o . o r g "`1
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May 1, 2020 June 5, 2020 Mscw
Eric Johnson,Administrator
City of Oak Park Heights
14168 Oak Park Blvd. N.
Oak Park Heights, MN 55082
RE: Central Automotive, Oak Park Heights
Dear Mr.Johnson,
The Middle St. Croix Watershed Management Organization (MSCWMO) received an application for project review on
April 14th, 2020 for the proposed Central Automotive development, located within MSCWMO boundaries and in the
City of Oak Park Heights. Revised submittal materials were received May 20th, 2020. The proposed project qualifies for
full review under the MSCWMO 2015 MSCWMO Watershed Management Plan (WMP). The revised submittals contain
sufficient information to determine compliance with the performance standards identified in Section 7.0 of the
MSCWMO Watershed Management Plan. The MSCWMO recommends - .•- - - - . - .-- - ••
comment:,approval with the following three conditions:
1. SWPPP is incomplete
a. Inspection and Maintenance records shall include:
i. Rainfall amounts must be obtained by a properly maintained rain gauge installed onsite, or by a
weather station that is within one mile or by a weather reporting system.
ii. Requirements to observe, describe, and photograph any discharge that may be occurring during
the inspection.
- - • - -- -
a. Use separate pervious/impervious runoff calculations
longer than the existing Tc. There will not be much sheet flow for this DA, mostly shallow
concentrated or channel flow.
Wellheiad Protection Area (WHPA) therefore infiltration is probated.
2. Dedications or easements are needed over the stormwater facility
3. Maintenance agreement is required.
The enclosed checklist contains detailed information on project review and the policies and performance standards of
the WMP. Feel free to contact me at 651-330-8220 x22 or mdowning@mnwcd.org if you have any questions regarding
these comments.
Middle St. Croix Watershed Management Organization Member Communities
Afton, Bayport, Baytown, Lakeland, Lakeland Shores, Lake St. Croix Beach, Oak Park Heights, St. Mary's Point, Stillwater, ft West Lakeland
June 5,2020
Page 2 of 2
Sincerely,
Matt Downing
MSCWMO, Interim Administrator
Enclosure
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
suu..n.
MIDDLE ST. CROIX WATERSHED MANAGEMENT ORGANIZATION
455 HAYWARD AVE . N . --1 ~`
O A K D A L E , MINNESTOA 5 5 1 2 8
Phone 651 . 330 . 8220 x22 fax 6 5 1 . 330 . 7747 www . mscwmo . org t'
PROJECT REVIEW Mscw •
...1
. Iona
MSCWMO Project Review ID: 20-006
Project Name: Central Automotive Ittry�
Applicant: Anderson Engineering
Purpose: Construction of a new automotive repair shop
Location: 59th St and Osgood Ave N, Oak Park Heights, MN
Review date: 06/04/20
Recommendation:Approval with three conditions Revise and resubmit. See red items in checklist and the
1. SWPPP is incomplete (see checklist for required items)
a. Inspection and Maintenance records include:
i. Rainfall amounts must be obtained by a properly maintained rain gauge installed onsite, or by a
weather station that is within one mile or by a weather reporting system.
ii. Requirements to observe, describe, and photograph any discharge that may be occurring during
the inspection.
. ..
a. Use separate pervious/impervious runoff calculations
longer than the existing Tc.There will not be much sheet flow for this DA, mostly shallow
3. The maximum ponding depth for infiltration allowed is 18".
Wellhead Protection Area (WHPA) therefore infiltration is probated.
2. Dedications or easements are needed over the stormwater facility
3. Maintenance agreement is required.
Applicability:
® Any project undertaking grading,filling, or other land alteration activities that involve movement of 100 cubic
yards of earth or removal of vegetation on greater than 10,000 square feet of land
® Any project that creates or fully reconstructs 6,000 square feet or more of impervious surface
Middle St. Croix Watershed Management Organization Member Communities
Afton, Bayport, Baytown, Lakeland, Lakeland Shores, Lake St. Croix Beach, Oak Park Heights, St. Mary's Point, Stillwater, a West Lakeland
2
n All major subdivisions or minor subdivisions that are part of a common plan of development. Major
subdivisions are defined as subdivisions with 4 or more lots.
n Any project with wetland impacts
❑ Any project with grading within public waters
❑ Any project with grading within buffers
❑ Any project with grading within 40-feet of the bluff line
❑ Development projects that impact 2 or more of the member communities
n New or redevelopment projects within the St. Croix Riverway that require a building permit that adds five
hundred (500) square feet or more of additional impervious surface
n Any project requiring a variance from the current local impervious surface zoning requirements for the
property
n Any land development activity, regardless of size,that the City determines is likely to cause an adverse impact
to an environmentally sensitive area or other property,or may violate any other erosion and sediment control
standard set by the member community.
SUBMITTAL ITEMS:
Electronic submittals are highly encouraged
® A completed and signed project review application form and review fee
® Grading Plan/Mapping Exhibits
a. Property lines and delineation of lands under ownership of the applicant.
b. Delineation of existing on-site wetlands,shoreland and/or floodplain areas (including any buffers).
c. Ordinary High Water(OHW) elevations and datum, as determined by the MDNR(if applicable).
d. Existing and proposed site contour elevations related to NAVD 1988 datum (preferred) or NGVD, 1929.
Datum must be noted on exhibits.
e. Drainage easements covering land adjacent to ponding areas,wetlands, and waterways up to their 100-year
flood levels and covering all ditches and storm sewers.Access easements to these drainage easements
and to other stormwater management facilities shall also be shown.
f. Minimum building elevation for each lot.
g. Identification of downstream water body.
® Permanent Stormwater Management System in compliance with the requirements of the NPDES SDS
Construction Stormwater Permit and MSCWMO Performance Standards.
a. Impervious areas (Pre-and Post-Construction).
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
3
b. Construction plans and specifications for all proposed stormwater management facilities.
c. Location(s)of past, current or future onsite well and septic systems (if applicable).
® Other exhibits required to show conformance to these Performance Standards
n A Stormwater Pollution Prevention Plan in compliance with the requirements of the NPDES SDS Construction
Stormwater Permit
® Grading Plan/Mapping Exhibits:
a. Delineation of the subwatersheds contributing runoff from off-site, proposed and existing on-site
subwatersheds, and flow directions/patterns.
b. Location,alignment, and elevation of proposed and existing stormwater facilities.
c. Existing and proposed normal water elevations and the critical (the highest)water level produced from the
100-year 24-hour storms.
d. Location of the 100-year flood elevation, natural overflow elevation, and lowest floor elevations.
® Hydrologic/Hydraulic Design Exhibits:
a. All hydrologic and hydraulic computations completed to design the proposed stormwater management
facilities shall be submitted. Model summaries must be submitted.The summaries shall include a map that
corresponds to the drainage areas in the model and all other information used to develop the model.
b.A table(or tables) must be submitted showing the following:
i.A listing of all points where runoff leaves the site and the existing and proposed stormwater runoff rates
and volumes.
ii. A listing of the normal water levels under existing and proposed conditions and the water levels produced
from the storm and runoff events listed above for all on-site wetlands, ponds,depressions, lakes,streams,
and creeks.
❑ Dedications or easements for the portions of the property which are adjacent to the facility and which lie below
the 100 year flood level. For sites within public right-of-way, no easement is required.
❑ A proposed maintenance agreement,which may be in the format of Appendix K, or other form approved by the
city.
HISTORY&CONSIDERATIONS:
SPECIAL OR IMPAIRED WATER
® This site drains to,and is within one mile of special or impaired water and complies with enhanced protections.
a.Scenic or Recreational river C.1., C.2.,C.3.
b.Scientific and Natural area C.1.,C.2.,C.3.
c. Waterbody with a TMDL C.1., C.2.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
4
C.1. Stabilization initiated immediately and all soils protected in seven days/provide temp basin for five acres
draining to common location.
C.2.Treat water quality volume of one inch of runoff by retaining on site unless not feasible due to site
conditions (See Part III.D.1. design requirements).
C.3. Maintain buffer zone of 100 linear feet from Special Water.
EROSION AND SEDIMENT CONTROL[A checked box indicates compliance]
n A Storm water Pollution Prevention Plan(SWPPP)that meets the National Pollutant Discharge Elimination System
(NPDES)requirements.
Narrative
® Identify the person knowledgeable and experienced who will oversee the implementation of the SWPPP;the
installation, inspection,and maintenance of the BMPs.
a. Identifies the person who will oversee the BMP inspection and maintenance.
b. Identify the training requirements are satisfied.
c. Inspections performed once every 7 days.
d. Inspections performed within 24 hours of a rain event greater than 0.5 in/24 hours.
e. Inspection and Maintenance records include.
i. Date and time of inspection.
ii. Name of person(s)conducting inspections.
iii. Finding of inspections, including the specific location where corrective actions are needed.
iv. Corrective actions taken (including dates,times, and party completing maintenance activities).
v. Date and amount of rainfall events greater than 0.5 in/24 hours.
vi. Rainfall amounts must be obtained by a properly maintained rain gauge installed onsite, or by a
weather station that is within one mile or by a weather reporting system.
vii. Requirements to observe, describe, and photograph any discharge that may be occurring during the
inspection.
viii. All discovered nonfunctional BMPs must be repaired, replaced, or supplemented with functional
BMPs within 24 hours after discovery, or as soon as field conditions allow.
® Describes procedures to amend the SWPPP and establish additional temporary ESC BMPs as necessary for site
conditions.
® Describes the installation timing for all Erosion Sediment Control (ESC) Best Management Practices (BMPs).
® Describes final stabilization methods for all exposed areas.
® Methods used to minimize soil compaction and preserve topsoil must be described.
® Describes dewatering technique to prevent nuisance conditions, erosion,or inundation of wetlands?
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
5
NA Identifies any specific chemicals and the chemical treatment systems that may be used for enhancing the
sedimentation process on the site, and how compliance will be achieved with the permit requirements.
® Describes pollution prevention management measures
a.Storage, handling,and disposal of construction products, materials,and wastes.
b. Fueling and maintenance of equipment or vehicles;spill prevention and response.
c.Vehicle and equipment washing.
d. No engine degreasing allowed on site.
e.Containment of Concrete and other washout waste.
f. Portable toilets are positioned so that they are secure.
Plan sheets
NA Temporary Sediment Basins required(10 acres draining to common location or 5 acres App.A)
Basin design meets the following criteria:
a.Adequately sized—2-year, 24-hour storm, minimum 1,800 feet/acre;or no calculative minimum
3,600ft3/acre.
b. Designed to prevent short circuiting.
c. Outlets designed to remove floating debris.
d. Outlets designed to allow complete drawdown.
e. Outlets designed to withdraw water from the surface
f. Outlets have energy dissipation.
g. Have a stabilized emergency spillway.
h. Situated outside of surface waters and any natural buffers.
® Locations and types of all temporary and permanent Erosion Control BMPs.
a. Exposed soils have erosion protection/cover initiated immediately and finished within 7 days.
b. Wetted perimeters of ditches stabilized within 200 feet of surface water within 24 hours.
c. Pipe outlets have energy dissipation within 24 hours of connecting.
® Locations and types of all temporary and permanent Sediment Control BMPs.
a.Sediment control practices established on down gradient perimeters and upgradient of any buffer zones.
b.All inlets are protected.
c.Stockpiles have sediment control and placed in areas away from surface waters or natural buffers.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
6
d. Construction site entrances minimize street tracking?
e. Plans minimize soil compaction and, unless infeasible to preserve topsoil.
f. 50 foot natural buffers preserved or(if not feasible) provide redundant sediment controls when a surface
water is located within 50 feet of the project's earth disturbances and drains to the surface water.
® Tabulated quantities of all erosion prevention and sediment control BMPs.
® Stormwater flow directions and surface water divides for all pre-and post-construction drainage areas.
® Locations of areas not to be disturbed (buffer zones).
® Location of areas where construction will be phased to minimize duration of exposed soil areas.
NA Blufflines are protected from construction activities in urban (40 foot buffer) areas and rural areas (100-foot
buffer).
LAKE,STREAM AND WETLAND BUFFERS
NA A buffer zone of unmowed natural vegetation is maintained or created upslope of all water bodies (wetlands,
streams, lakes).
NA A 50 foot natural buffer or(if a buffer is infeasible) provide redundant sediment controls when a surface water is
located within 50 feet of the project's earth disturbances and stormwater flows to the surface water.
NA If adjacent to a Special or Impaired Water an undisturbed buffer zone of not less than 100 linear feet from
the special water is maintained both during construction and as a permanent feature post construction.
STORMWATER MANAGEMENT[A checked box indicates compliance]
® Water quality treatment is provided prior to direct discharge of stormwater to wetlands and all other water bodies.
Rate and Flood Control Standards
® The peak rate of stormwater runoff from a newly developed or redeveloped site shall not exceed the 2-, 10-, and
100-year 24-hour storms with respective 2.8,4.2, and 7.3-inch rainfall depths with MSCWMO approved time
distribution based on Atlas 14 for existing and proposed conditions. The runoff curve number for existing
agriculture areas shall be less than or equal to the developed condition curve number.The newly developed or
redeveloped peak rate shall not exceed the existing peak rate of runoff for all critical duration events, up to and
including the 100-year return frequency storm event for all points where discharges leave a site during all phases of
development.
® Predevelopment conditions assume"good hydrologic conditions"for appropriate land covers as identified in TR-55
or an equivalent methodology. Runoff curve numbers have been increased where predevelopment land cover is
cropland:
Hydrologic Soil Group A: Runoff Curve Number 56
Hydrologic Soil Group B: Runoff Curve Number 70
Hydrologic Soil Group C: Runoff Curve Number 79
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
7
Hydrologic Soil Group D: Runoff Curve Number 83
® Computer modeling analyses includes secondary overflows for events exceeding the storm sewer systems level-of-
service up through the critical 100-year event.
NA In sub-areas of a landlocked watershed,the proposed project does not increase the predevelopment volume or
rate of discharge from the sub-area for the 10-year return period event.
n Flowage easements up to the 100-yr flood level have been secured for stormwater management facilities (such as
ditches and storm sewers).
® Lowest floor elevations of structures built adjacent to stormwater management features and other water bodies
are a minimum of two feet above the 100-year flood elevation and a minimum of two feet above the natural
overflow of landlocked basins.
Volume Control Standards
® Calculations/computer model results indicate stormwater volume is controlled for new development and
redevelopment requirements per the MSCWMO Design Standards.
1. New Nonlinear Development 1.1" * new impervious surfaces
2. Reconstruction/Redevelopment Projects 1.1" * reconstructed impervious surfaces
3. Linear Projects 0.55" * new and/or fully reconstructed impervious surface and 1.1"from net increase in
impervious area
4. Sites with Restrictions-flexible treatment options documentation has been provided.
Volume Retention Required (cu.ft.) Volume Retention Provided (cu. ft.)
BMP Volume
21040 sf*1.1" = 1929 cu.ft. BMP#1 4313 cu.ft.
Total Proposed 4313 cu.ft.
Total Required 1929cu.ft.
Flexible Treatment Options(when applicable)
• Applicant demonstrated qualifying restrictions as defined in Section 7.2.2 (4) of the 2015 MSCWMO Watershed
Management Plan that prohibits the infiltration of the entire required volume.
® MIDS calculator submission removes 75%of the annual total phosphorous.
® MIDS calculator submission removes 60%of the annual total phosphorous.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
8
Infiltration/Filtration Design Standards
® Proposed stormwater management features meet or exceed NPDES General Construction Permit requirements are
designed in conformance with the most recent edition of the State of Minnesota Stormwater Manual.
NA None of the following conditions exist that prohibit infiltration of stormwater on the site
a. Areas where vehicle fueling and maintenance occur.
b. Areas with less than three(3)feet of separation distance from the bottom of the infiltration system to the
elevation of the seasonally saturated soils or the top of bedrock.
c. Areas where industrial facilities are not authorized to infiltrate industrial stormwater under an National
Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) Industrial Stormwater Permit
issued by the MPCA.
d. Areas where contaminants in soil or groundwater will be mobilized by infiltrating stormwater.
e. Areas of Hydrologic Soil Group D(clay)soils
f. Areas within 1,000 feet up-gradient,or 100 feet down-gradient of active karst features unless allowed by a
local unit of government with a current MS4 permit.
® Minimum setbacks from the Minnesota Department of Health for infiltration practices are met
Setback Minimum Distance(ft)
Property line 10
Building foundation* 10
Private well 35
Public water supply well 50
Septic system tank/leach field 35
*Minimum with slopes directed away from the building
® Pretreatment devices(s) remove at least 50%of sediment loads. If downstream from a potential hot spot, a
skimmer is in place to facilitate cleanup.
® Water quality volume will be discharged through infiltration or filtration media in 48 hours or less.
a. For bioretention (biofiltration and bioinfiltration)volume control management facilities above ground with
vegetation the period of inundation shall be calculated using the maximum water depth below the surface
discharge elevation and the soil infiltration rate.
b. For infiltration basin volume control management facilities the period of inundation shall be calculated using the
maximum water depth below the surface discharge elevation and the soil infiltration rate.
NA Appropriate soil borings have been conducted that meet the minimum standards.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
9
a. A minimum of one boring was conducted at the location of the infiltration facility for facilities up to 1,000 ft2;
between 1,000 and 5,000 ft2,two borings, between 5,000 and 10,000 ft2, three borings and greater than 10,000
ft2 4 borings plus an additional boring for every 2,500 ft2 beyond 12,500 ft2
b. Soil borings extend a minimum of five feet below the bottom of the infiltration practice. If fractured bedrock is
suspected,the soil boring goes to a depth of at least ten feet below the proposed bottom of the volume control
facility.
c.A minimum of three feet of separation to the seasonal water table and/or bedrock.
d. Identify unified soil classification.
NA The least permeable soils horizon identified in the soil boring dictated the infiltration rate.
NA Additional flows are bypassed and are routed through stabilized discharge points.
® Filtration basin demonstrates a basin draw down between 24 hours and 48 hours.
® Filtration system Iron Enhanced Sand Filter is sized to bind soluble phosphorous removal for 30 year functional life
of the system using the published value of 17 lbs phosphorous removal per 20 yards of 5% by weight iron filings to
95%sand.
n identify ac h.iilrl curvev and mPthorl to demonstrate infiltratinn orfiltratinn hacin ir functioning.
NA Construction plans provide adequate construction guidance to prevent clogging or compaction and demonstrate
performance.
a. Excavation within 2.0 feet of final grade for infiltration/filtration systems is prohibited until contributing
drainage areas are constructed and fully stabilized.
b. Rigorous sediment and erosion controls planned to divert runoff away from the system.
c. Installation of volume control facilities must occur in dry soil conditions. Excavation, soil placement and rapid
stabilization of perimeter slopes must be accomplished prior to the next precipitation event.
d. Excavation shall be performed by an excavator with a toothed bucket. Use excavator bucket to place materials.
Construction equipment shall not be allowed into the basin.
e. Prior to the release of any remaining fee or security,the permit holder must provide documentation that
constructed volume control facilities perform as designed.
® There is a way to visually verify the system is operating as designed.
® A minimum 8.0' maintenance access is provided to all stormwater facilities.
WETLAND PERFORMANCE STANDARDS
NA Direct discharge of stormwater to wetlands and all other water bodies without water quality treatment is
prohibited.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township
10
NA Any potential changes to the hydrology of the wetland (i.e. changes to the outlet elevation or contributing drainage
area) must be reviewed to evaluate the impact of both the existing and proposed wetland conditions and approved
by the MSCWMO.
NA Land-altering activities shall not increase the bounce in water level or duration of inundation from a 2.0-inch 24-
hour storm for any downstream wetland beyond the limit specified in Table 7.2 for the individual wetland
susceptibility class.
Middle St. Croix Watershed Management Organization
MEMBER COMMUNITIES:
Afton,Bayport,Baytown Township,Lakeland,Lakeland Shores,Lake St.Croix Beach,Oak Park Heights,St.Mary's Point,Stillwater and West Lakeland Township