Dec 19, 2012 – Cell 3 – Exposed Mudflat

Dredge and Rainey Report
Cell 3 – Exposed Mudflat

December 19, 2012

 

Summary of accomplishments:

  • Most of Cell 3 is at -1” ML or better
  • Pulled 3 sections of hose out of the pond
  • Total time pumped directly into Cell 3 (.366 acres) = 59.75 hours
  • Total time in study cells = 206 hours

Impediments: low water in the pond => no dredging

This report can be downloaded in PDF file format by clicking the Dredge and Rainey Report Cell 3 – Exposed Mudflat hyperlink.

Tuesday, December 18

The day was crisp, clear and cold, and fortunately for me, Timmy had errands in town. This meant I didn’t have to bring the Avocet and got to ride out to the Sanctuary in the enclosed cabin of the Goose. As we headed out into Little Vermilion Bay, marsh fire plumes were visible in all directions as various land managers took advantage of the steady breeze. Timmy had repaired the airboat this weekend just past, and we passed his first burn at the bay end of the canal into the Sanctuary. Smoke still rose from the active edge of the burn.

Wednesday, December 19

Early morning light revealed a constant stream of snow geese searching for open areas to feed. As we headed over to the dredge site, we could see them swirling down into the area just burned, with smoke still rising not far away. I suppose even geese enjoy a warm breakfast on such a chilly morning!

The wind and tides had not been great over the past week, so I was not surprised to find that water was too low in the pond to dredge. However, I was surprised that the canoe was pulled out, since I had left it full of water in the mud next to the “dock.” Timmy had managed to flip it over in the last high water to drain it, and had pulled it into the marsh to dry.

The water level was at -2.5” ML, de-watering Cell 3 and exposing our mudflat in all its glory. Most of it was already covered by a multitude of footprints – avian, mammalian and reptilian. The south end that was recently mudcracks, was covered again by a layer of unbroken mud. This end was the first part of Cell 3 to be brought up to marsh level, and is also the first part of the cell to show exuberant new growth (figure 3). I’m amazed that this 3rd cell is the largest, and yet is below average in the time it has taken to fill it. Our methodology has indeed improved!

Even though the winter weather causes tidal depression (low water) that makes it difficult to dredge, the frequent mud exposure to air and subsequent reflooding seems to stimulate plant tillering and seed germination. While most of the above ground grass has gone dormant and lost the deep green of summer and gold of autumn, the edges of our fill areas are bright with new shoots.

It had been two weeks since we last visited the site, and it was pleasant to have the time to walk around the area just to observe. The new growth of Spartina patens marshhay was becoming more and more evident in areas where the fill has had time to “age.” It had almost closed in on the original channel we had used for the canoe into Cell 5, and was being kept open across containment 5a only by the frequent crossing of a resident gator (Figure 5).

Figure 1. New mud exposed under and next to the boardwalk with signs of recent visitors.

Figure 1. New mud exposed under and next to the boardwalk with signs of recent visitors.

Figure 2. The new mud in Cell 3 on the left contrasts with the shallow water of Cell 2 on the right.

Figure 2. The new mud in Cell 3 on the left contrasts with the shallow water of Cell 2 on the right.

Figure 3. A scour under the containment created during our last dredging event, or by tidal movement since then, was obvious with the low water.

Figure 3. A scour under the containment created during our last dredging event or by tidal movement since then, was obvious with the low water.

Figure 4. View to the east along the south shore of Cell 3, showing new growth all along the new mudflat. The rope is connected to the outfall end of the hose in the middle of the cell.

Figure 4. View to the east along the south shore of Cell 3, showing new growth all along the new mudflat. The rope is connected to the outfall end of the hose in the middle of the cell.

Figure 5. Spartina patens was showing vigorous growth in areas that had been filled earlier. The photo on the Left is in Cell 4 and Right is the reed containment (5a) between Cell 5 and 3, where the vegetation is competing with the frequent crossing of the resident gator.

Figure 5. Spartina patens was showing vigorous growth in areas that had been filled earlier. The photo on the Left is in Cell 4 and Right is the reed containment (5a) between Cell 5 and 3, where the vegetation is competing with the frequent crossing of the resident gator.

Figure 6. The view to the west across the mudflats of cells 5 and 4.

Figure 6. The view to the west across the mudflats of cells 5 and 4.

We couldn’t dredge with no water over the mud, but we still had plenty of time in our day. Timmy had been wrestling with the long hose in Cell 3 every time he moved it, and we decided that we really don’t need any more delta building to the south end since it is already above marsh level. The length of the hose pulling against the mud makes the job more difficult than it needs to be, so we decided to use the afternoon to pull some sections out. We went back to the house and loaded up the 4-wheeler, hammers and extra rope.

Since we intended to use the 4-wheeler to pull, we started with a hose connection near the levee. It was almost too heavy with water to pick up until the connection seal was broken and the water was allowed to drain. Timmy tied the end connected to the pond to the 4-wheeler with a short rope, but was unable to pull it. Aimed downhill, it was still full of water, and the hose in the pond was in mud. We counted 3 sections of hose, disconnected it, and easily carried it to the top of the levee after it drained.

Timmy and I pushed the long section of hose still attached to the pond hose across the marsh in line with the 4-wheeler to make it as easy as possible to pull. While he moved the 4-wheeler to the old airboat crossing, I used a long pole to push the part of the flex hose that bent over the bank into the mud over the marsh until it was as straight as possible. Timmy brought a long rope, tied it securely to the free end of the hose and took the end of the rope to the 4-wheeler on high ground. The first pull had the hose sliding successfully out of the pond. While Timmy did the hard work of pulling with the 4-wheeler, I stayed in the marsh to keep up with the free end to make sure it didn’t get caught and to keep an eye on the end of the hose in the pond. We weren’t sure if we needed to pull 2 or 3 sections out.

As he pulled, the hose in the pond pulled against the soft mud until it found an efficient route, then slid quite well following itself in a self-made, curving ditch. I signaled Timmy (yelled loud) when I thought it was close to where it needed to be. Together, we pushed the hose over the marsh back toward the dredge end. I got out my pole and managed to lever the muddy flex hose over the marsh and bank into position. The 4-wheeler was moved again in line, and Timmy pulled the hose up the rest of the way to meet the connection. We had pulled 3 sections out and still had plenty of hose in the pond for mud management the next time we get to dredge (next year). Somehow, I was all muddy and sweaty, and Timmy looked fresh as a daisy. Go figure. But, this task was complete!

Figure 7. We had to take the hose apart to pull the "slack" out of the pond.

Figure 7. We had to take the hose apart to pull the "slack" out of the pond.

Figure 8. The 4-wheeler was critical to shortening the hose.

Figure 8. The 4-wheeler was critical to shortening the hose.

Figure 9. Geese crossing the dredge site on their way to the newly burned marsh area to the northeast.

Figure 9. Geese crossing the dredge site on their way to the newly burned marsh area to the northeast.

I realized, as I stood admiring the efficient curve to the hose, that I had removed one of the ropes that added length to the outfall end, in case we needed it. The end of the hose had moved quite a distance. Oh dear. I hurriedly crossed the walkway, and found my fears realized. The end of the rope was out in the mud.

LSU had left a number of 10-ft PVC poles stuck in the marsh, so I picked out one that didn’t look critical and used it to carefully work the only loop in the rope toward shore, gratefully retrieved it, and retied the borrowed length of rope with a sturdy knot.

As I finished, I heard and then saw, more geese heading toward the still burning marsh to our northeast. It was such a wonderful reward for the day’s effort! Walking back to the levee, I admired the results of our effort. The big S-curve the hose had made was now one gentle long curve, and it seemed to be aimed in the perfect direction for the next dredge flow. I can’t wait! Unfortunately, we would not be able to resume until next year since this was the last opportunity I had before the holidays. On the bright side, this would give our mud some time to consolidate before the next layer is applied.

Figure 10. The hose was in the perfect position for the next available dredge event.

Figure 10. The hose was in the perfect position for the next available dredge event.

The last task we had before we left the dredge site, was to pull the canoe out. It had developed a few leaks, we weren’t likely to use it in Cell 3 any longer with no water, and Timmy wanted to get it cleaned up and repaired over the break. Timmy went to get the 4-wheeler, and I flipped it over and pulled it a little closer to the levee. The 4-wheeler hauled it up to high ground, both were loaded onto the Goose, and we headed back to the house.

See you next year!!!

Figure 11. Timmy hauling the canoe to high ground.

Figure 11. Timmy hauling the canoe to high ground.

Figure 12. Estimated status of the study cells as of December 7, 2012. Gray lines are containment, orange line is planned containment, yellow lines are walkways, yellow crescents are recent locations of the outfall, bright green is new vegetation, white dots are PVC pole locations.

Figure 12. Estimated status of the study cells as of December 7, 2012. Gray lines are containment, orange line is planned containment, yellow lines are walkways, yellow crescents are recent locations of the outfall, bright green is new vegetation, white dots are PVC pole locations.

 Karen A Westphal and Timmy J Vincent, National Audubon Society
Louisiana Coastal Initiative and the Paul J Rainey Wildlife Refuge
6160 Perkins Road, Suite 215, Baton Rouge, LA 70808
225-768-0921 office, kwestphal@audubon.org

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