November 13, 2014 CAG Meeting

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River Mile 10.9 Removal Action Overview River Mile 10.9 Removal Action Overview River Mile 10.9 Removal Action Overview River Mile 10.9 Removal Action Overview

Modified from CPG’s RM10.9 Removal Action Final Design Report dated Nov. 2013

River Mile 10.9 Removal Action Activities River Mile 10.9 Removal Action Activities River Mile 10.9 Removal Action Activities River Mile 10.9 Removal Action Activities

Dredging: Approx. 2 feet of contaminated sediment were removed.

Capping: A cap of approx. 2 feet was placed over the “post –dredge sediment.” The cap consisted of the following layers in ascending order:

• Active material/sand mixture was placed above the post-dredge sediment (remaining contaminated sediment) to prevent contaminants from migrating to the surface of the cap.

• Geotextile was placed over the active material/sand mixture. The geotextile is a fabric layer that keeps the active layer/sand mixture in place and prevents penetration by the armor stones.

• Armor stones, the sizes of which were determined by an engineer, were placed over the geotextile. Placement of the stones happened after the geotextile panels were placed.

• Sand (habitat layer) was placed over the armor stones to fill in voids to help reestablish the mudflat ecosystem. 2

August 17, 2013 August 28, 2013

August 7, 2013 to October 4, 2013: Dredging operations conductedApproximately 2 feet of contaminated sediments were removed.

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November 13, 2013 – A telebelt (device to convey

material from barge) is depositing the active

material/sand mixture over the post dredge sediment.

November 15, 2013 – Photo shows an area where

active material/sand mixture had been placed.

November to December 2013: Active Material/Sand Mixture Placement

Approximately 10 inches of active material/sand mixture placed over post dredge sediment

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March 15, 2014

Left Photo: geotextile panel being placed

near the fire deptartment boat launch

Right Photo: armor stone placement

overlying the newly placed down geotextile

panel. CPG’s contractor can be seen trimming

the extra geotextile.

March 2014: Placement of geotextile and armor stone

Geotextile: fabric layer used to keep the

active layer/sand mixture in place and to

prevent penetration.

Armor stones: were placed after the

geotextile panels were laid down.

� Keeps the geotextile in place and also

helps to protect the underlying cap from

erosion due to high river flows and

propeller wash from recreational

boating.

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April 14, 2014: Photo of armor stones over

recently-placed geotextile panel.

Two different types of armor stone are seen

in this photograph:

Type B (the smaller of the two stones

used) was used when the underlying

substrate was hard pan. Type B armor stones

were placed closer to shoreline where the

flow rate is expected to be lower (less

potential erosion).

Type A (the larger of the two stones used)

were determined by CPG’s engineer to

withstand a 100-year storm event.

April 2014: Placement of geotextile and armor stone

6Photograph taken in area south of “No Dredge Zone”

April 23, 2014

North of the “No Dredge Zone”

Mini excavator is in the background leveling out the

armor stone north of the “No Dredge Zone”

South of the “No Dredge Zone”

Type B stone can be seen here

Exposed geotextile panel is shown here as it extends

beyond the armor stones. When placing the geotextile

panel:

� CPG’s contractor laid the panels out flat to extend

approx. 5-15 feet off the vegetated shoreline,

anchoring it off the trees/brush until the armor stone

could be installed.

� Process resulted in approx. 5 feet excess geotextile in

places beyond where dredging/capping occurred

� CPG’s contractors then trimmed back the geotextile to

the edge of cap. Exposed geotextile is not a result of

erosion

April 2014: Placement of geotextile and armor stone continued

“No Dredge Zone” Area

South

North

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May 8, 2014: Initial test run of sand being applied via a telebelt

over the armor stone. Area photographed is south of the “No

Dredge Zone.”

May 2014: Sand (habitat layer) placement beganSand layer was applied over the armor stones to fill in voids to help reestablish the mudflat ecosystem.

May 9, 2014: Photo of an area where one layer of sand was

initially applied.

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May 12, 2014: Photo taken three days after the initial

placement of two sand layers (on May 9th).

May 2014: Sand (habitat layer) placement continued

May 9, 2014: Photo of sand layer 24 hours after initial

test. Two layers of sand have been placed.

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May 27, 2014:

Background: The telebelt is conveying

first layer of sand in an area just south of

the fire department boat launch.

Foreground: An area that was covered in

the prior week.

The row of exposed armor stone in the

foreground is outside the dredge line and

was not slated to be covered by sand.

� Helps to anchor the extra geotextile

that extends beyond the area

dredged/capped.

� CPG’s contractor cut additional fabric

once the row of armor stone anchoring

the geotextile had been placed.

May 2014: Sand (habitat layer) placement continued

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May 29, 2014: Photo taken while standing south of “No

Dredge Zone” looking north. The row of armor stone (acting

as an anchor) can be seen on the right side of the photo.

May 29, 2014: Photo taken from the southern most

cap/dredge location and looking north. The final cap

surface post installation can be seen here.

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May 29, 2014: CPG started to demobilize from RM10.9

� Site visits with EPA, CPG and

members of the boating

community

� EPA and CPG discuss and plan for

an effort to address high spots of

armor stones. EPA and CPG

engage in discussions regarding

placement of buoy markers

� CPG and EPA identify areas of

elevated armor stones and CPG

takes coordinates of the

locations

Photo credit: Harvey Morginstin. Photograph titled “Lyndhurst LT June 24 2014 037.jpg”

and was provided to EPA on 6/24/2014 via email.

June 2014 - August 2014

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September 2014

� CPG begins effort on Sept. 29th to

move high spots of armor stones

� EPA oversees this effort

September 29, 2014: CPG effort to move high spots of armor stones

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CPG’s contractor removes high spots of armor stones in areas

closer to the channel. Area is south of “No Dredge Zone.”

Conditions prior to start of work. Row of armor stones anchoring

geotextile seen in foreground. A red buoy marker not placed by

CPG and EPA is seen. Also, a rower passing by.

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September 30, 2014: CPG effort to move armor stones

CPG’s contractor continues to manually remove high spots of armor stones.

Based on observations that day, it was estimated that approximately 3-4 inches of sediment had accumulated above the sand layer. River level

at low tide was higher than anticipated. As such, work was scheduled to resume the following week.

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October 6, 2014:

Last day of effort

Area near fire

department

boat launch

CPG’s contractor utilized a

tracked vehicle in effort to

remove armor stones in

area north of “No Dredge

Zone.”

CPG’s contractor manually removes

armor stones near channel in area north

of the “No Dredge Zone.”

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RM10.9 site visits after CPG’s efforts to remove high spots of armor stones

November 4, 2014: Area north of “No Dredge Zone.” Row of

armor stones anchoring geotextile is in foreground. These stones

are outside the dredged/capped area, line almost the entire

length of the mudflat, and will remain as they help to anchor the

underlying geotextile layer.

October 8, 2014: Area south of “No Dredge Zone.”