Dredge Report, July 13, 2011

Wednesday, July 13, 2011

Timmy and Karen were at the dredge at 6:30am and Karen crushed a finger between the boat and dredge by 6:31. Ouch.




To change the oil in the water pump, we needed to raise it off of the deck. It was too heavy to bet on propping it up safely, so Timmy left to go get the come-along and chase down an unidentified boat that we saw zooming down the main canal (It turned out to be a McIlhenny) while Karen did some housekeeping on the barge and arranged extra shade. With the come-along, Timmy hoisted the pump up and set it over a bucket for spill back-up. Again, the oil plug was in an awkward position and we had to rig a conduit to catch the flow, but spilled not a drop into the water.

Everything was back together and hooked up for pumping by 7:50 am. Timmy dredged, Karen assisted. Then Karen went ashore and took the canoe out for a view of the working discharge and to inspect containment.

After being moved last week, the discharge floats are pinching the discharge flow so that some of it is diverted below and behind the float. Substantial flow was observed still flowing over the new delta into the side inlet and creating eddies throughout the rest of the cell. Containment 5a is holding well with very little sediment flow-through. Containment 5b however, had an exit plume at the north end of the containment and effluent was flowing in a serpentine fashion behind the discharge and right through the containment at that point into cell #4. Standing on the containment and probing with a paddle proved that the flow had excavated under the containent at that point. Having just gotten the dredge underway and watching gathering clouds, the decision was that it wasn’t worth trying to fix at the moment.

Karen went back to the dredge, then cut cane while Timmy dredged until thunder drove us back to camp at 10:30. Showers, lunch, change clothes and a nap helped recovery from the morning activities.

Discharge is constricted between floats(Left). Containment 5a with little flow(Right).

Sediment plume moving under north end of containment 5b.

Around 2:00, radar showed that the thunderstorms were moving out, so we returned in a light drizzle to start dredging again at 2:15.  Karen returned to the pond and installed a piece of plywood against the containment to block the sediment escape channel. Within minutes, another flow was observed toward the middle of the containment coming through the cane. Karen observed a large area of fluid mud within Cell 4 and checked the distribution with the paddle.  It is apparent that overflow has begun filling Cell 4 and a nice plume is circulating within the confined area. Based on these observations, Timmy and Karen are planning to put in the outer containment for the entire area at our next opportunity using plywood to retard or prevent the loss of sediment to the open pond.

As the afternoon cooled, Karen again cut cane while Timmy dredged, and we shut it down at 6 pm for a total of 6 hours dredging for the day.

Estimated fill status for cells 4 & 5. Fill is to the water level in areas marked with bright purple and shows considerable sediment in the darker purple areas. Yellow crescents mark discharge points, and the green lines are the existing containment.


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