Dredge Report, July 22, 2011

Friday, July 22, 2011

Sunrise revealed another promise of rain looming on the horizon. Karen had constructed a pontoon that we intend to test as a discharge float, and we had been trying to get it dried out all week. Finally got it sealed up this morning. We cut the plywood and 2x4s to finish the containment and loaded all on Goose. We left the pontoon on a high spot along the bank at the site, and loaded the airboat to finish the outer containment wall. The wake from the airboat tested the rigidity of the wall and it proved to be quite resistant, not transferring but a few ripples into the pond from each wave.

In a total of about 3 hours, we installed 178 feet of containment. We were rather glad we didn’t have to cut that much cane, and it’s a trade off in cost to buy lumber or spend the man-hours. Now we can compare the performance of reeds vs plywood, not only in containing mud, but how fast it falls apart.

Timmy putting in screws, securing plywood to 2x4s(Left). Karen putting in screws on her end, holding plywood in place with a foot(Right).

With the previous reed placement at Cell #4, the outer containment for the experimental cells is complete. Interior containment will be placed as the discharge is moved.

View of containment #1 looking northeast toward the landing and dock.

 

View of containment #1 looking west from the walkway dock. Eventually another line of containment will be placed between the walkway and this containment to separate cells 1 & 2.

This figure shows the layout of the experimental cells. North is to the top. Planned containment is indicated by orange lines and labels, and completed containment is shown in green. Containment #1 was completed this week with plywood. Cell 5 is being filled, with yellow crescents indicating the former positions of the discharge.

Lagniappe – Test Site update

After containment was completed, we stopped by the Test Site that had been partially filled earlier this year.  We were happy to find that there was new vegetation colonizing the fill material. Spikerush (Eleocharis sp), Bacopa and one of the grasses were starting to take root.
Arrows indicate some of the areas that show new growth.

The Spartina alterniflora that Timmy had planted next to the containment at the walkway was also doing very well, growing vigorously and putting out a lot of tillers.

The photo to the left shows Spartina alterniflora growing vigorously in the mud next to the reed containment, and Bacopa growing in the reeds.

It doesn’t appear that the sediment has settled significantly in the last few months. When the experimental cells are filled, we plan to return to this area to expand the contained area, add more fill and build on what we started.

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