ITEM 2.1 _Enigneer ReportReview No. 1
ENGINEERING REVIEW
Residential Subdivision
for the City of Otsego
by
Hakanson Anderson
Submitted to: Brian Krystofiak, P.E., Carlson McCain
cc: Lori Johnson, City Administrator
Tami Loff, City Clerk
Dan Licht, City Planner
Andy MacArthur, City Attorney
Rick Packer, Mattamay Homes, Inc.
Reviewed by: Ronald J. Wagner, P.E.
Brent M. Larson, P.E.
Date: July 1, 2014
Proposed
Development: Boulder Creek
Street Location A portion of the Section 27, T121, R23. south of 78th Street,
of Property: west of Odean Avenue, and north of C.S.A.H. 37.
Applicant: Rick Packer
7201 Washington Avenue
Suite 201
Edina, MN 55439
Developer: Mattamay Homes, Inc.
Owners of Record: Mattamay MPLS Partnership
Purpose: Boulder Creek is a proposed 360 lot single-family residential
development on 156+ acres in the City of Otsego, Wright County,
Minnesota. The proposed development will be served with
municipal water, sanitary sewer, storm sewer, and public streets
typical of an urban setting.
Jurisdictional Agencies: City of Otsego, Wright County, Minnesota Department of
(but not limited to) Health, Minnesota Department of Natural Resources, Minnesota
Pollution Control Agency, Wright Soil and Water Conservation
District.
Permits Required: NPDES, Minnesota Department of Health (water), and
(but not limited to) Minnesota Pollution Control Agency (sanitary sewer)
SUBDIVISION CONFIGURATION LOT SIZE DENSITY
1) The City of Otsego Comprehensive plan show the proposed development area as future R-5,
R-6, an d R-7 zoning. It appears that the proposed zoning is PUD withtypical 30' setbacks,
a minimum lot width of 55' and minimum lot area of 7150 sq.ft. Also a portion of the
City Planner's recommendations.
development is within a Shoreland District. Zoning and density requirements shall be per the
EXISTING CONDITIONS
1) Label the existing zoning for the area within the development boundary as well as the 2
exceptions along 70th Street.
2) Label the existing 100 yr or Ordinary High Water elevations (OHW) for all the existing
wetlands and storm ponds within 150' of the site.
3) Label the size, type, and elevations for all utilities within 150' of the site boundary. (Along
78th Street there are a 12" DIP watermain, 18" PVC sanitary sewer, and 30" RCP storm
sewer, with 8" water and sanitary sewer stubs and an 18" storm sewer stub to the south at
Parell Avenue. Along 76th Street there is a 12" DIP stub at the property line.)
4) Show widths of existing streets and ROW within 150' of the site boundary.
TRAFFIC/ACCESS ISSUE
1) The site provides one access point to 78th Street to the north, one access point to 76th Street in
the NW and one access point to 70th Street (CSAH 37) to the south. The streets are to be
widened at the intersections of 78th Street and 70th Street to provide for appropriate turning
lanes.
2) City staff has worked with the developer regarding the required layout and necessary street
sizing requirements for the proposed development. Palmgren Avenue is proposed to have
parking along one side of the street in various areas as well as 5' sidewalk along both sides
for the entire length of the street. The street will be widened to 33' wide in the areas where
parking is proposed (vs. the typical 28' wide). This will be enough to provide (2) 11' drive
lanes and (1) 8' parking lane.
3) The typical section for Palmgren Avenue and Packard Avenue shall be per a geotechnical
engineer's recommendation for a 10 Ton design.
4) Provide an 100' tangent between all horizontal curves.
PRELIMINARY PLAT
1) The streets shall be names as follows:
a. Street A (north -south portion) — Palmgren Avenue NE
b. Street A (northern east -west portion) — 74th Street NE
c. Street A (souther east -west portion) — 73`d Street NE
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d. Street B — Palmgren Circle NE
e. Street C (east -west portion) — 77th Street NE
f. Street C (north -south portion) —Park Avenue NE
g. Street D — Park Court NE
h. Street E — 76th Street NE
i. Street F — 76th Court F
j. Street G — Palmgren Avenue NE
k. Street H — 74th Circle NE
1. Street I — 74th Court NE
in. Street J — 73rd Street NE
n. Street K — 72nd Street NE
o. Street L - Page Avenue NE
p. Street M — 72'd Street NE
q. Street N (north -south portion) — Parell Avenue
r. Street N (east -west portion ) — 71St Street NE
s. Street O — Padgett Avenue NE
t. Street O (cul-de-sac) — Padgett Court NE
u. Street P — Packard Avenue NE
2) Temporary cul-de-sacs are required at the ends of all streets with 2 or more driveways (i.e.
Streets C, J, K and both ends of N). Easements are required around these temporary cul-de-
sacs.
3) A couple areas require a temporary construction easement to be obtained from adjacent land
owners in order to grade along the eastern property edge. Written confirmation of these
agreements shall be obtained prior to final approval as they may alter the proposed plans
significantly.
4) All swales shall be contained within the proposed drainage and utility easements. (i.e. rear
yard swale along Lots 7-10 and 13-14, Block 4 is outside of the easements.)
5) An easement shall cover the trail through Outlots D, E, and K.
PRELIMINARY SITE/UTILTIY PLAN
_Sanitary Sewer System
1) Water and sewer service shall be stubbed towards the two exception properties along 70th
Street. These services shall be covered by easements if not within the right-of-way.
2) Depending on the type of soils (clay) watertight Hamilton Kent Lifespan Systems or
approved equal are required on all sanitary sewer manholes on this project. This should be
brought to the contractor's attention as soon as possible.
3) A new 10" sanitary sewer connection to the existing sanitary sewer manhole at 78th Street is
proposed at 849.0. The existing 8" has an invert of approx. 848.8. The existing 8" stub shall
be removed and new 10" cored. This will require 78t Street to be ripped up and to be closed
or atleast reduced to one lane. A traffic control plan shall be submitted for this work. The
time of this construction shall be such that impacts to traffic are minimized (i.e. 9 am to 4
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pm). It should also be noted that the need to remove the existing stub pipe and replace with a
larger pipe is a result of the changes to the proposed Page Avenue as requested by the
developer of Pheasant Ridge 6th — 8th Addition.
Water System
4) An 8" watermain shall be placed between the east end of Street F and south end of Street C
to provide a loop. The watermain shall be covered but a 20' wide easement centered over the
pipe.
5) Provide a 16" X 16" X 12" cross at the intersection of Street P and 70th Street. Provide a
70LF 16" stub to the west, and a 50 LF 16" stub to the east for future connections by others.
The cross and stubs shall be located approximately 10' south of the right-of-way.
Streets
6) The City standards required a minimum 250' horizontal curve for residential streets. Some
of the proposed streets have 90' horizontal curves proposed. This has been done due to
various physical constraints do not allow a 250' radius. This has been allowed in similar
situation throughout the City.
7) The temporary cul-de-sac at the connection point to 76th Street shall be removed, connection
made with a through street and the area restored as part of this development.
8) All streets shall have a minimum 90' vertical curve or meet the minimum K value for a 30
mph street.
9) Pedestrian ramps are needed at many of the street intersections along Streets A and G to
connect the sidewalks.
10) We suggest placing the sidewalk along the south side of Street K. Street K will be a trough
street in the future and this will eliminate a pedestrian crossing at Street N.
Details
11) Watertight Hamilton Kent Lifespan Systems are required on all sanitary sewer manholes on
this project and therefore no chimney seals are required. Add Std. Plate 307 and remove Std.
Plate 308.
PRELIMINARY GRADING PLAN
1) Please label the lots with the same lot and block numbers found on the preliminary plat for
ease of relating the separate drawings to each other.
2) Typically all lot grading shows a minimum of 2% grade with a few exceptions that can be
addresses in more detail with the final plan submittal.
3) Concrete valley gutters will be required at all intersection that do not provide a minimum of
I% grade across them.
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4) The emergency overflow (EOF) for Lots 213 — 227 is 875.10 (at the low point in street south
of these lots). The EOF needs to be lowered to 875.0 or the lowest opening of these lots
raised 0.1' to provide the minimum 1.5' of freeboard.
5) The respective pond and wetland in Pheasant Ridge 6th -8th Addition are: Pond, NWL = 871.6
and 100 yr HWL=873.8; Wetland, NWL = 871.3 and 100 yr HWL = 872.6. are 871.6. label
these elevation of the plans.
6) The grading north of lots 297 and 304, along the trail shall be revised to provide a minimum
2% grade. As proposed runoff may pool next to the trail in the park area.
7) Pond 1P has a NWL = 864.0 and a 100 yr HWL = 867.8 while 872L in the Lefebvre Creek
Study (same as Pond 1P) has a NWL = 866.0 and 100 yr HWL = 870.2. The lowest opening
proposed along the creek is 874.5. The proposed elevations provide the required separation
from the HWL in either situation.
SURFACE WATER MANAGEMENT
1) The stormwater runoff south of 78th Street and East of Street B is proposed to discharge off-
site to an existing storm sewer pipe in Pheasant Ridge 6th Addition. It must be verified that
the existing storm sewer pipe and downstream pond can accommodate this flow.
2) The Lefebvre Creek Trunk Stormwater Study, dated 1999 indicates two (2) 33" culverts are
sufficient at the street crossings of Lefebvre Creek. The plans have a two (2) 36" culverts
proposed. Trunk storm water credits will be provided within the Development Agreement.
3) The drainage ditch (Lefebvre Creek) shall be cleaned out to provide an 8' wide channel.
Trunk storm water credits will be provided within the Development Agreement.
4) Provide inlet spread calculations for the storm sewer. Not all catch basins need to be
calculated as long as the most critical are evaluated. 2/3' of the drive lane are allowed to be
inundated along normal residential streets. Streets A and G should be less than 1/2 of the
drive lane. A 10 yr storm event shall be used for this analysis.
WETLANDS
1) Wetland impacts are proposed to be replaced via wetland bank and has been approved b
WCA. The Notice of Decision has been sent. Army Corp of Engineers is still reviewing the
site.
SWPPP
1) The site disturbs more than 50 acres, discharges to a Special water within 1 mile, therefore
the SWPPP shall be submitted to the MPCA a minimum of 30 day prior to construction for
review.
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OTHER CONSIDERATIONS
1) Submit wetland delineation report by Kjohlaug Environmental Services, Inc.
2) Submit soil borings and report with a recommended R-value for typical residential streets
and a recommended street section or Gravel Equivalent for the minor collector street
(Palmgreen Avenue).
3) A statement certifying the environmental condition of the site including the presence of any
hazardous substance as defined in Minnesota Statutes 11513.02, Subd 8 is required.
4) Provide a contact name and phone number for the developer.
SUMMARY AND/OR RECOMMENDATION
We recommend approval contingent upon the above comments being addressed.
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