February 6, 2007
Lake Emma Township Board
Lake Emma Township, MN
RE: Half Moon Road
Dear Lake Emma Twp. Chair and Board Members,
The township has requested our services to analyze improvement options and cost
estimates for Half Moon Road. This letter examines three alternatives for maintaining
the existing road and three alternatives for vacating the existing road. Cost estimates are
enclosed.
Half Moon Road provides a connection between County Road 4 and County Road 40 and
is approximately 1.8-miles long. Approximately 0.9-miles of Half Moon Road is located
within 15-ft of Blue Lake and has been petitioned to be vacated. The roads average
width is 18-ft. The average daily traffic is estimated between 50 and 90 vehicles per day.
26-parcels are located along Half Moon Road and 11 of those parcels are located on the
portion of road proposed to be vacated.
Maintaining Half Moon Road
Three alternatives for maintaining Half Moon Road have been examined. The
alternatives focus on reducing the road’s environmental impacts on Blue Lake.
Environmental impacts created by the road include; increased sediment loadings, dust,
untreated runoff, and shoreline erosion. The following alternatives will be examined;
narrowing the road, increasing the buffer zone, redirecting runoff, and implementing
erosion and dust control measures.
Alternative #1 - Reduce the road width and expand the buffer zone between the
road and the lake
Currently the buffer zone ranges from 5-ft to 10-ft with an average slope of 1:1. Buffer
zones are established to infiltrate and treat nutrient loaded runoff before it enters the lake.
Expanding the buffer zone by an additional 5-ft will allow for a more gradual sloped
bank and a longer time of concentration for the runoff, allowing more runoff to infiltrate
into the soil and be consumed by vegetation.
The road width will be reduced from 18-ft to 16-ft. Shifting the road away from the lake
will require some additional excavation. Existing ditches will need to be reconstructed
and some side slope cutting is expected. In areas with steep side slopes, retaining walls
will need to be constructed. Base-One should be applied to the road surface to reduce the
amount of gravel erosion and dust created by the road. Calcium chloride is also
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recommended for dust control. Signage stating “LOCAL TRAFFIC ONLY” or “NO
THRU TRAFFIC” is recommended to reduce the amount of traffic using the road.
All disturbed areas along the road will be planted with native vegetation. A mixture of
shoreline grass seed, forb seed, trees, and shrubs will be planted along the lake shore.
The additional vegetation along the shoreline will help stabilize the lake shore, reduce
erosion, and treat storm water runoff. The vegetation will also improve the aesthetics of
the shoreline.
Any construction activity along the lake shore will require strict erosion control
measures. Silt fences, floating booms, temporary sediment ponds, and other BMP’s will
be required until construction activity is complete and vegetation has been re-established.
The estimated total cost of alternative #1 is $168,000.
Alternative #2 - Redirect runoff away from the lake and construct ditches and
sediment ponds to mitigate runoff
The road surface will be graded to slope away from the lake. Base-One will be applied to
the road surface to reduce erosion and dust. Ditches will be constructed on the outside of
the roadway. Dry sedimentation ponds will be constructed intermittently to treat runoff
before it outlets into the lake. Retaining walls are anticipated in areas containing steep
side slopes. The township will need to establish a 66-ft right-of-way along the entire
roadway to accommodate ditching and ponds. The estimated total cost of alternative #2
is $232,000.
Alternative #3 - Construct bituminous curb and overlay road with bituminous
pavement
Runoff will be directed away from the lake and mitigated as described in Alternative #2.
Bituminous curb will be constructed on the lake side of the road. The bituminous curb
will further prevent any surface runoff from entering the lake. The bituminous surface
will provide a more consistent grade for drainage and will eliminate erosion and dust
problems. The estimated total cost of alternative #3 is $410,000.
Vacating Half Moon Road
Three alternatives for vacating Half Moon Road have been developed. Vacating Half
Moon Road will focus on removing environmental hazards to Blue Lake and restoring
the right-of-way back to its natural state.
Alternative #4 - Excavate the road surface and restore vegetation.
The top 6” of the road surface will be excavated. Excavated gravel can be salvaged for
turn-arounds and other township projects. The excavated area will be graded to match
existing grades and 2” of topsoil will be placed over the disturbed site. The road bed will
be re-vegetated with shoreline grasses, forbs, trees, and shrubs. Turn-arounds will be
constructed at the east end and west end of Half Moon Road. The turn-arounds will be
36’ x 50’. A 66-ft right-of-way will need to be established at turn-around locations.
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After project completion, the vacated right-of-way can be turned over to the property
owners. The estimated total cost of alternative #4 is $154,000.
Alternative #5 - Restore wetlands in conjunction with Alternative #4.
Wetlands will be constructed in areas identified as pre-existing wetlands. According to
wetland inventory maps, wetlands are identified in the northeast and northwest corners of
Blue Lake and in various locations along the shoreline. We estimate that approximately
one-half an acre of wetland can be restored. To establish wetlands, the township will
need to excavate identified areas to one foot above the high water level. Excavated areas
will be seeded with wetland grasses, forbs, and saplings. After project completion, the
vacated right-of-way will need to be transferred into a conservation easement.
Constructing wetlands will provide an excellent buffer to the lake and will help restore
the natural hydrology of the area. Wetland credits can be sold back to the state for
approximately $13,000 per acre. The estimated total cost of alternative #5 is $223,000.
Alternative #6 - Construct a walking trail in conjunction with alternative #4.
Using salvaged aggregate from the roadway, a walking trail can be constructed to
meander along the lake shore. The walking trail will need to be 8-10-ft wide. We
recommend planting some additional trees and shrubs along the trail to shield the trail
from nearby homes.
Site amenities such as benches, picnic tables, and
interpretive/educational elements may also be included to attract visitors. The vacated
right-of-way will need to be transferred into a trail easement or conservation easement.
The estimated total cost of alternative #6 is $177,000.
The cost estimates developed are preliminary estimates provided to assist in the decision
making process. All estimates include a 20% contingency. Engineering fees include the
following; centerline survey, topography survey, wetland delineation, storm water
pollution prevention plan, construction plans, specifications, bid proposal, permitting, and
other project specific design requirements. Construction services include construction
staking, construction inspection, and construction management. Cost estimates do not
include any legal fees or any costs associated with right-of-way acquisition.
I hope this report answers some of your questions regarding Half Moon Road. Please
feel free to contact me at (218) 444-1859 with any questions or comments you may have.
Sincerely,
WIDSETH SMITH NOLTING & ASSOCIATES, INC.
Darren Laesch, E.I.T.
Enclosures