Corps sets conditions on draft permit

After an extensive application review, the U.S. Army Corps of Engineers, Walla Walla District, issued a draft permit to the Idaho Transportation Department for the Sand Creek Byway.

The Department of the Army draft permit was issued with conditions to

minimize impacts to Sand Creek and to mitigate wetlands proposed to be filled

for construction of the project.

The conditions are:

1. Turbidity curtains, cofferdams, sheet piles or other types of cofferdams

will be used to keep work areas isolated from flowing water, dewater

construction areas, and to prevent erosion of sediments into Sand Creek and

Lake Pend Oreille.

2. Prior to the removal of the temporary inflatable cofferdams, temporary

turbidity curtains will be installed around the perimeter of the cofferdams.

Individual cofferdam segments will be slowly and carefully deflated so that

water is slowly returned to the proposed dredging location to minimize

turbidity in Sand Creek. Turbidity curtains shall not be removed until water

quality testing indicates that turbidity levels in the dredging area do not

exceed those in Sand Creek.

3. Dredging shall occur only during the winter drawdown or low water period.

4. All clearing and grubbing immediately adjacent to Sand Creek shall be

done during the winter drawdown or low water period.

5. All disturbed soil areas along Sand Creek, including authorized fill

areas, shall be adequately stabilized and protected to minimize erosion of

sediment into open water areas.

6. Best Management Practices will be installed as specified in the Storm

Water Pollution Prevention Plan to isolate any potential water run-off from

disturbed areas into Sand Creek and Lake Pend Oreille during storm events.

7. All surface water and water generated from dredging activities will be

pumped to stormwater treatment ponds, construction detention basins,

vegetated swales, or stormwater treatment systems and treated to eliminate

turbidity prior to discharge in Sand Creek through controlled outlets.

8. Fish passage in the project area will be maintained throughout

construction of the project.

9. Construction of the North Interchange Mitigation Site shall occur as soon

as possible once the initial function of sediment pond during construction is

no longer necessary. The site will be contoured and planted per the "US 95

Sandpoint, North & South, North Interchange Wetland Mitigation Plan" sheets

2-4 of 14. The following acreage and wetland types shall be established:

0.51 acres of forested wetlands, 0.18 acres of scrub-shrub wetlands, and 0.86

acres of emergent wetlands.

10. Construction of the Habitat Enhancement Areas shall be completed

concurrent with project construction to mitigate for impacts to aquatic areas

as a result of the construction of the pedestrian/bicycle path.

11. Mitigation sites shall be monitored for a period of five years.

Mitigation wetlands shall meet the 1987 Corps of Engineers Wetland

Delineation Manual criteria at the end of the five-year monitoring period.

For all types of wetland mitigation (emergent, scrub-shrub and forested

wetlands), the mitigation sites will have at least 45 percent cover at all

sample sites at the end of three years. The mitigation wetlands will have at

least 80 percent cover at all sample sites at the end of five years. The

mitigation sites will have an observable, continual increase in cover

percentage, plant species diversity, and plant age/size class diversity

throughout the five-year monitoring period. The sites will allow for natural

recruitment of desirable wetland species to be included as cover and as

species diversity during long-term monitoring. The mitigation wetlands shall

be dominated by native vegetation. Non-native noxious weeds shall cover less

than 10 percent of the mitigation sites at the end of three years. For

scrub-shrub wetland mitigation sites, ITD will establish at least 15 percent

cover of all shrub species at the end of three years, and 30 percent cover of

all shrub species at the end of the five-year monitoring period. ITD shall

maintain at least 75 percent survival of planted shrubs at the end of the

five-year monitoring period. For forested wetland mitigation sites, ITD will

establish at least 15 percent cover of all tree species at the end of three

years, and establish at least 30 percent cover of all tree species at the end

of the five-year monitoring period. ITD shall maintain at least 75 percent

survival of planted trees and shrubs at the end of the five-year

monitoring period. Wetland mitigation sites monitoring reports shall be

submitted to this office by the following January of each year monitoring is

required. Should the site(s) not meet the success criteria above at the end

of the five-year monitoring period, ITD will submit a contingency plan.

12. ITD is responsible for the long-term maintenance of the Sandpoint High

School Mitigation Site, North Interchange Mitigation Site, and the Habitat

Enhancement Areas regardless of any agreements made with third parties

related to these sites.

13. ITD shall provide copies of all written agreements executed with the

Cities of Sandpoint and Ponderay regarding the operation and maintenance and

protection of the Habitat Enhancement Areas within one year of the completion

of construction of these areas. However, this does not relieve ITD of the

responsibility for long-term maintenance of these areas.

14. Four core samples of new surface material at the channel hydraulic

dredging site would be collected after the final grade has been reached and

prior to the removal of the cofferdam. Samples will be collected when the

final grade has been reached to assure the required one-foot sample depth is

achieved. If samples from the newly exposed channel bottom have contaminant

concentrations above the Dredged Material Evaluation Framework screen levels

and Idaho Initial Default Target Levels, an additional one foot of material

would be removed and the excavation backfilled with clean fill to the

designed elevation to prevent direct contact with the water column and biota.

15. ITD shall comply with all requirements of the Memorandum of Agreement

developed and executed on April 14, 2005 between the Idaho State Historic

Preservation Office, FHWA, ITD, the Corps (Walla Walla and Seattle

Districts), the Kootenai Tribe of Idaho, and the Kalispel Tribe to mitigate

adverse effects of the project on historic properties.