HomeMy WebLinkAbout2021-11-04 MSCWMO Plan Approval Letter -St,11.Yrte,
MIDDLE ST. CROIX WATERSHED MANAGEMENT ORGANIZATION
455 HAYWARD AVE . N , OAKDALE , MINNESTOA 55128 ■ `'' :
Phone 651 . 330 . 8220 x22 fax 6 5 1 . 3 3 0 . 7 7 4 7 www . m s c w m o . o r g
Raytown
November 4, 2021 Mscw
Toro \
Eric Johnson,Administrator
City of Oak Park Heights
14168 Oak Park Blvd. N.
Oak Park Heights, MN 55082
RE: Park Dental, Oak Park Heights
Dear Mr.Johnson,
The Middle St. Croix Watershed Management Organization (MSCWMO) received an application for project review on
September 15th, 20021 for the demolition of existing building and utilities and reconstruction of a new building and
associated improvements at 13961 60th St. N, located within MSCWMO boundaries and in the City of Oak Park Heights.
The proposed project qualifies for full review under the MSCWMO 2015 MSCWMO Watershed Management Plan
(WMP). After the initial MSCWMO staff review the applicant was asked to revise and resubmit H&H model materials as
well as provide a higher level of engineering review for the suitability of infiltration in a high vulnerability DWSMA on
September 17th, 2021. The higher level of engineering review was received on October 19th, 2021 and revised H&H
model submittal materials were received November 3rd, 2021. 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 approval with the following five conditions:
1. Timing of inlet protection is provided in the SWPPP or Grading, Drainage& Erosion Control Specifications.
2. Flowage easements up to the 100-yr flood level have been secured for stormwater management facilities.
3. A proposed maintenance agreement approved by the city is provided.
4. Methods to demonstrate infiltration or filtration basin is functioning as designed prior to the release of any
remaining fee or security are identified in the plans.
5. Plans/SWPPP specifies that for installation of infiltration systems:
a. the installation occurs in dry soil conditions,
b. excavation,soil placement and rapid stabilization of perimeter slopes must be accomplished prior to the
next precipitation event,and
c. excavation and placement of materials shall be performed by an excavator with a toothed bucket.
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, & West Lakeland
November 4,2021
Page 2 of 2
The enclosed checklist contains detailed information on project review and the policies and performance standards of
the WMP. Also enclosed is a copy of the high level of engineering review for determining the suitability of infiltration at
the site. Feel free to contact me at 651-330-8220 x22 or mdowning@mnwcd.org if you have any questions regarding
these comments.
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
Se+Ilrab.
MIDDLE ST. CROIX WATERSHED MANAGEMENT ORGANIZATION
455 HAYWARD AVE . N . ■ �—
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
PROJECT REVIEW
MSCW
MSCWMO Project Review ID: 21-010
et
Project Name: Park Dental St. Croix Valley
Applicant: Vicki VanDell
Purpose: Demolition of existing buildings and utilities, reconstruction of a new building with associated
improvements.
Location: 13961 60th St N, Oak Park Heights
Review date: 11/04/21
Recommendation: Approval with the following conditions:
1. Timing of inlet protection is provided in the SWPPP or Grading, Drainage& Erosion Control Specifications.
2. Flowage easements up to the 100-yr flood level have been secured for stormwater management facilities.
3. A proposed maintenance agreement approved by the city is provided.
4. Methods to demonstrate infiltration or filtration basin is functioning as designed prior to the release of any
remaining fee or security are identified in the plans.
5. Plans/SWPPP specifies that for installation of infiltration systems:
a. the installation occurs in dry soil conditions,
b. excavation,soil placement and rapid stabilization of perimeter slopes must be accomplished prior to the
next precipitation event, and
c. excavation and placement of materials shall be performed by an excavator with a toothed bucket.
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
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.
❑ Any project with wetland impacts
n Any project with grading within public waters
n Any project with grading within buffers
7 Any project with grading within 40-feet of the bluff line
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, 8 West Lakeland
2
n 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
❑ Any project requiring a variance from the current local impervious surface zoning requirements for the
property
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).
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
® 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.
3
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.
n 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.
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]
® A Storm water Pollution Prevention Plan (SWPPP)that meets the National Pollutant Discharge Elimination System
(NPDES)requirements.
Narrative
4
® 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).
Timing of inlet protection not listed in sequencing.
® 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?
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
5
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.
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).
6
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
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.
® 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
7
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
0.882 ac *1.1" = 3,522 cu.ft. BMP#1 2,212 cu.ft.
BMP#2 1,760cu.ft.
Total Required 3,522cu.ft. Total Proposed 3,972cu.ft.
Flexible Treatment Options(when applicable)
NA 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.
NA MIDS calculator submission removes 75%of the annual total phosphorous.
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.
® 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.
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. Higher level of engineering review completed for DWSMA,
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
8
® 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.
® Appropriate soil borings have been conducted that meet the minimum standards.
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.
® The least permeable soils horizon identified in the soil boring dictated the infiltration rate.
® Additional flows are bypassed and are routed through stabilized discharge points.
NA Filtration basin demonstrates a basin draw down between 24 hours and 48 hours.
NA 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 17lbs.phosphorous removal per 20 yards of 5% by weight iron filings to
95%sand.
ri Identify as build survey and method to demonstrate infiltration or filtration basin is functioning.
n 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.
9
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.
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.
water
October 18,2021
ecology
Vicki VanDell
community
Loucks,Inc.
7200 Hemlock Lane
Suite 300
Maple Grove, MN 55369
Subject: Higher level engineering review
Park Dental Site
Oak Park Heights, Minnesota
Dear Ms. VanDell:
We reviewed the hydrogeology information available for the Park Dental Site. The site is shown on
Figure 1. The project is within the wellhead protection area(WHPA)and drinking water supply
management area(DWSMA) for the City of Oak Park Heights municipal water supply wells. The area is
classified as having high vulnerability. According to the Minnesota Stormwater Manual and the
Construction Stormwater General Permit, infiltration areas that are constructed in high vulnerability areas
within a DWSMA must have a higher level engineering review.
Guidance documents
The Minnesota Stormwater Manual(MPCA,2021)states that:
"There are two conditions in which infiltration is prohibited under the Construction Stormwater
General Permit unless a higher level of engineering review is conducted and demonstrates that a
functioning treatment system will prevent adverse impacts to groundwater.
1.An Emergency Response Area(ERA)within a DWSMA classified as moderate vulnerability
2. Outside of an ERA within a DWSMA classified as having high or very high vulnerability"
The Park Dental site meets Condition 2. To complete a higher level engineering review,the stormwater
manual guidance is:
"The primary concern for this condition,however, is to identify or protect other receptors,
which typically will be private well owners. This can be achieved by limiting the risk of
contaminant exposure,as described above for condition 1.A second option is to conduct a
receptor survey. This is a two step process:
1. "Determine the one year travel time surrounding the infiltration practice. This can be
estimated using simple calculators...
2. "Determine if there are any active receptors utilizing the aquifer within the one year
travel time area.
Receptor Survey
The Prairie du Chien aquifer is the primary drinking water aquifer in the Oak Park Heights area. The one
year time of travel through the aquifer can be measured from the wellhead protection areas calculated for
the nearby municipal wells, as shown on Figure 1. The maximum distance for a one-year time of travel is
approximately 2,000 feet.Note that it is the same for all the municipal wells.
Emmons&Olivier Resources, Inc.is an Equal Opportunity Affirmative Action Employer
1919 University Avenue West,Suite 300 St.Paul,MN 55104 T/651.770.8448 F/651.770.2552 www.eorinc.com
Figure 1 also shows the one-year time of travel around the subject property. Two Oak Park Heights
municipal wells were identified as potential receptors downgradient from the subject property. Other
potential receptor wells were identified from the Minnesota Well Index(MDH,2021). Two private
residential wells(Unique ID 123503 and 242865)were identified within the one-year time of travel and
downgradient from the Park Dental site. Several other wells in the area were identified as being
abandoned and sealed. Oak Park Heights has a municipal drinking water supply, so any residential wells
in this area are likely to be used exclusively for non-drinking water purposes such as lawn watering. This
reduces the potential threat of health effects from contaminated groundwater.
The Oak Park Heights wellhead protection plan delineated emergency response areas using a groundwater
model to calculate the one-year time of travel area for each well,as shown on Figure 1. The Park Dental
site lies outside of these areas. The municipal wells are not potential receptors for storm water infiltrating
at the Park Dental site within the designated one-year time limit.
Both of the identified residential wells are completed in the Prairie du Chien aquifer, as indicated by the
well logs included as Attachment A. The one-year capture areas for the two residential wells were
calculated using the method prescribed by the Minnesota Department of Health(MDH,2018),but using
one-year pumping rates instead of 10-year pumping rates. The pumping rate for a residential well was
assumed to be 300 gallons/day(109,500 gallons/year). The calculated wellhead protection radius is
shown in Table 1.
Table 1.Calculated Wellhead Protection Radius(r)for Residential Wells
Q(1 yr)
Well# (gal) n L(ft) r(ft)
123503 109500 0.1 112 55.8
242865 109500 0.1 52 81.9
The capture areas were also extended upgradient 2000 feet to reflect the one-year time of travel. The
calculated one-year capture areas for the residential wells are shown on Figure 1. A more rigorous
groundwater model would show some interference between the Oak Park Heights municipal wells and the
residential wells,but it is still clear that the Park Dental site is outside the one-year capture areas of the
residential wells.
Conclusion
This higher level of engineering review has found that stormwater infiltrating from the Park Dental site
will have no adverse impacts to groundwater because there are no active receptors utilizing the aquifer
within the one-year travel time area of the receptors. Therefore,the project meets the requirements of the
Construction Stormwater General Permit.
References
Minnesota Department of Health(MDH),2018. "Preliminary Wellhead Protection Area
Delineation."Available online at Preliminary Wellhead Protection Area Delineation
(state.mn.us).
Minnesota Department of Health(MDH),2021. Minnesota Well Index.Available online at
https://mnwellindex.web.health.state.mn.us/
Minnesota Pollution Control Agency(MPCA),2021. "Minnesota Stormwater Manual. Guidance and
recommendations for conducting a higher level of engineering review for stormwater infiltration in
DWSMAs and Wellhead Protection Areas."Available online at
https://stormwater.pca.state.mn.us/index.php?title=Main Page
1919 University Avenue West,Suite 300 St. Paul,MN 55104 T/651 770 8448 F/651 770 2552 www.eorinc.com
Figure 1
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Project Location Wells Park Dental
( J Wellhead Protection Municipal Nearby Wells and
ERA,1-year TOT • Private ii,. , sow at.
NMIWellhead Protection Areas
ecology
1 Year Capture Area 8 Other e
community (Residential Well) DWSMA vulnerability
L,_I1Year TOT HighMI 0 Miles 0.5
Groundwater Flow Direction Moderate
1919 University Avenue West,Suite 300 St.Paul, MN 55104 T/651.770.8448 F/651.770.2552 www.eorinc.com
Attachment A-Residential Well Logs
Minnesota Unique Well No. MINNESOTA DEPARTMENT OF HEALTH
County Washington Entry Date 03/01/1989
123503 Quad Stillwater WELL AND BORING RECORD Update
Quad ID 1 ISD Minnesota Statutes Chapter 1031 Received Date 02/14/2014
Well Name Township Range Dir Section Subsection Use Status Well Depth Depth Completed Date Well Completed LiefReg.No.
CHAMPIONM, 29 20 W 4 BBAAC domestic A 185 ft. 185 ft. 10/25/1976 82084
Elevation 933 ft. Elev.Method 7.5 minute topographic map(+1-5 feet) Aquifer Plaine Du Chien Depth to Bedrock 73 ft Open Hole 170 - 185 ft Static Water Level 140 ft
Field Located By Minnesota Geological Survey Locate method Digitized-scale 1:24,000 or larger(Digitizing Universal Transverse Mercator(UTM)-NAD83-Zone 15-
Unique No.Verified Address verification Input Source Minnesota Geological Survey UTM Easting(X) 514292
Geological Interpretation Bruce Bloomgren Input Date 01/01/1990 UTM Northing(Y) 498684
Agency(Interpretation) Interpretaion Method Geologic study 1:24k to 1:100k
Depth(ft.) Elevation(ft.)
Geological Material Color Hardness From To Thickness From To Stratigraphy Primary Lithology Secondary Minor Lithology
SAND&CLAY&BOULDERS BROWN SFT-HRD 0 73 73 933 860 pebbly sand/silt/clay- sand clay boulder
LIMEROCK YEL/WHT HARD 73 185 112 860 748 Prairie Du Chien dolomite
Minnesota Well Index-Stratigraphy Report 123503 Printed on 10/18/2021
Minnesota Unique Well No. MINNESOTA DEPARTMENT OF HEALTH
County Washington Entry Date 10/09/1990
242865 Quad Stillwater WELL AND BORING RECORD Update
Quad ID 118D Minnesota Statutes Chapter 1031 Received Date 02/14/2014
Well Name Township Range Dir Section Subsection Use Status Well Depth Depth Completed Date Well Completed Lic/Reg.No.
29 20 W 4 BABACD domestic A 126 ft. 126 ft. MGS
Elevation 916 ft. Elev.Method 7.5 minute topographic map(+/-5 feet) Aquifer Prairie Du Chien Depth to Bedrock 42 ft Open Hole 94 - 126 ft Static Water Level 116 ft
Field Located By Minnesota Geological Survey Locate Method Digitization(Screen)-Map(:24,000)(15 meters Universal Transverse Mercator(UTM)-NAD83-Zone 15-
Unique No.Verified Information from owner-site Input Source Minnesota Geological Survey UTM Easting(X) 514518
Geological Interpretation Bruce Bloomgren Input Date 02/13/2004 UTM Northing(Y) 498686
Agency(Interpretation) Interpretaion Method Inferred from geophysical log
Depth(ft.) Elevation(ft.)
Geological Material Color Hardness From To Thickness From To Stratigraphy Primary Llthology Secondary Minor Lithology
GLACIAL DRIFT 0 42 42 916 874 Quaternary deposit drift
ST.PETER SANDSTONE 42 74 32 874 842 St.Peter Sandstone sandstone
PRAIRIE DU CHIEN GROUP 74 126 52 842 790 Prairie Du Chien dolomite
Minnesota Well Index-Stratigraphy Report 242865 Printed on 10/18/2021