3. Log House Ramp Memo 10-21-15w a t e r
e c o l o g y
community
Project Name 1 Log House Landing Boat Ramp Date 1 10/21/2015
To / Contact info 1 Jim Shaver (CMSCWD Administrator)
From / Contact info 1 Carl Almer (EOR), Britta Hansen (EOR)
Regarding 1 Concept Plan & Estimated Costs
Background
The intent of the Log House Landing boat ramp project is to provide a stabilized access point for
boat launching while also eliminating erosion and sediment transport to the St. Croix River from the
ramp and surrounding slopes. The current condition of the site is a highly erosive native soil/ rock/
gravel surface ramp that contributes sediment directly to the river. Frequent regrading and
resurfacing are required due to washouts from runoff from 2051h Street as well as vehicle rutting.
A variety of materials were explored as options for improving the access ramp. Bituminous, steel
matting, geotextile mats, and HDPE turf pavers were all considered. Ultimately it was determined
that due to the steep slope, concrete would be the most appropriate and durable material. No other
material could provide the amount of stable traction and strength required for vehicles to navigate
the 24% slope ramp. Concrete is also the most durable in terms of wave, wake, wind, ice, and
current exposure, and poses the least risk of being displaced due to high water.
Concept Design
Ramp & Access Drive - The attached concept plan proposes a combination of DNR supplied
concrete boat ramp planks and a reinforced concrete access ramp over geotextile fabric. 32
concrete planks are proposed at the base of the ramp where boats will be deposited and retrieved
from the water. The planks will extend approximately 15' beyond the OHW of 680' into the water,
but will not exceed a depth of 4', per DNR requirements. The planks will be set on a 13% slope,
which is within the preferred range of slopes for boat access. The proposed design affords
construction in accordance with State of Minnesota Specifications (State File SDG.00030, Sheet 14)
which is mandated by the (draft) Public Water Access letter agreement between the City and the
State. The access drive from the parking area to the boat ramp is proposed to be paved with a 6"
thick, reinforced concrete with a v-groove finish.
Additional Elements - The access drive is proposed to be bordered on either side by a clear
aggregate spillway over fabric in order to direct flows and prevent erosion. In addition, the steep
slopes on either side of the access drive are proposed to be stabilized and reinforced with 18-36"
boulders. Any disturbed area will be seeded with a native woodland mix. Currently an eroded foot
path exists approx. 40' to the north of the boat ramp access point. The concept plan proposes
formalizing and reinforcing the path with a rough cut stone stairway, fitted into the slope.
Other Considerations - Additional items not itemized in the preliminary cost estimate that could
provide added benefit include landscaping with shrubs and perennial plugs instead of seed; an
improved picnic area near the historic fireplace with decomposed granite surface, tables, and
educational signage; and a sediment basin in the far corner of the parking area to receive runoff
from 205th Street in order to direct sediment away from the reconstructed access drive, boat ramp,
and river.
FOR is an Equal Opportunity Affirmative Action Employer
Emmons & Olivier Resources, Inc. 651 Hale Ave N. Oakdale, MN 55128 T/ 651.770.8448 F/ 651.770.2552 www.eorinc.com