Dredge (and Rainey) Report Cell 4 filled with fluid mud, March 2, 2012

Dredge (and Rainey) Report
Cell 4 filled with fluid mud
March 2, 2012

Summary of accomplishments:

  • Moved outfall over
  • Cell 4 containment successfully raised water level 3 inches above pond level
  • Cell 4 filled to marsh level with fluid mud
  • Total time pumped directly into Cell 4: 53 hours
  • Total dredging time at study cells: 125.5 hours

Impediments: new pump passes larger material so hose clogs.

 

Tuesday, February 28

Karen went back to the camp with Timmy after a meeting of the Rainey Conservation Alliance at Avery Island.

 

Wednesday, February 29

We awoke to a very foggy morning. It was a warm and humid start for “leap day.” I rode along as Timmy took the Goose south to retrieve the ATVs from the chenier. We stopped along the way to take salinity readings as well. The recent multiple rainstorms have dropped the salinity in the canals back to around 3-4 ppm.

Figure 1. Foggy morning roseate spoonbills.	Figure 2. Foggy sunrise.

Figure 1. Foggy morning roseate spoonbills. Figure 2. Foggy sunrise.

Figure 3. Redtail wet and droopy from fog.   Figure 4. Bringing the ATVs back from the chenier.

Figure 3. Redtail wet and droopy from fog. Figure 4. Bringing the ATVs back from the chenier.

We stopped by camp so that I could bring the flat boat and made it to the dredge site by 9:00 am. It was already 72°, with south winds at 8mph and an overcast sky. Timmy unloaded the ATV from the boat, tied ropes onto the floating hose he had disconnected last week, and used the ATV to pull it up the bank until the next connection emerged from the water. He disconnected that one and we found that shells and sticks had made a plug at the end of flex hose coming from the dredge. I ran back and forth to the dredge to pump water while Timmy worked at the clog until it broke apart and flushed out. He then reconnected the hose, bypassing the floating hose since we thought it might be causing the problem.

Figure 5. Timmy pulling the hose out of the water with the ATV.

Figure 5. Timmy pulling the hose out of the water with the ATV.

At 11:00, we were startled by a boat horn piercing the dredge noise from behind us. Louisiana Wildlife and Fisheries enforcement agents that knew Timmy stopped by to see what we were doing. We shut the dredge down for a while to visit. After they left, we took the opportunity to eat lunch and then headed to the pond to see what an hour and half of pumping had done.

The water level of the pond was at -2ML, and the old delta was still above the water, as well as the new one around the outfall. A small flock of black-necked stilts, greater yellow-legs and blue winged teal flushed as we walked out to the end of the boardwalk. Fluid mud was evident three-quarters of the way across Cell 4, and it was backing up over containment 5b into the previously filled Cell 5.

We decided to move the pontoon, so paddled and poled the canoe out to Cell 4. Timmy walked the containment between Cell 4 and 5 to untie the pull ropes and bring them over to the north side.  We tried, but couldn’t move the pontoon very far. The hose has a big curve in it, and pulling the pontoon was pulling the hose against a large amount of mud. Timmy and I each had a rope to pull, and even with it wrapped around our bodies and using all our weight it wouldn’t budge more than a few feet. We even tried using a lever on the hose while Timmy pulled to no avail. We left it at least aimed in a different direction and returned to the dredge. Timmy suggested we bring the airboat out next week to move it.

Figure 6. Moving the outfall from the delta we created in about 9 hours of pumping.

Figure 6. Moving the outfall from the delta we created in about 9 hours of pumping.

We resumed dredging, but it wasn’t long before the hose clogged again. Timmy again used the ATV to haul the hose out of the water to get to the next joint to unclog it. By this time, it was really warm and breezy for a February day, at 81° with a south wind of 19mph, partly sunny. Apparently, the new pump passes larger particles so that it doesn’t clog as easily as the hose.

Figure 7. Timmy working to unclog the hose again.

Figure 7. Timmy working to unclog the hose again.

We have the dredge “walking” backwards near the south bank and was approaching the airboat ramp where we had the boat tied. We needed to move the left traveling cable back as well, so stopped dredging just long enough to rearrange everything.

Another hour and we stopped again for Karen to take Timmy over to the other boat. He needed to check out the installation of a water control structure on Vermilion property. So I dredged by myself until 5 pm. Thankfully, nothing clogged. Timmy returned as I was shutting everything down and helped me finish up so we had time to go to the pond.

At the pond, roseate spoonbills were working the shallows, and flushed with teal as we neared the end of the boardwalk. Black-necked stilts, yellow-legs, willet and even a common moorhen were more reluctant to leave.  Obviously, there is something very attractive in our mud.

Figure 8. Roseate spoonbills working the old delta on the right and teal to the left in the fluid mud.

Figure 8. Roseate spoonbills working the old delta on the right and teal to the left in the fluid mud.

 

Thursday, March 1

It dawned another muggy day. Karen cut bamboo into poles while Timmy went in to Shell Morgan to get fuel needed for boats, airboat & dredge. I also cut some plywood to use as patches for the containment.

Figure 9. Bundled roseaucane on the left, bamboo on the right.    Figure 10. Cutting bamboo into 5-ft lengths.

Figure 9. Bundled roseaucane on the left, bamboo on the right. Figure 10. Cutting bamboo into 5-ft lengths.

When he returned, we loaded up the flat boat and ran down to Christian Marsh to collect Timmy’s pirogue. We dropped it at the dredge site, then continued out the canal, across the bay, to the oil & gas canals at Cole’s Bayou to collect some Spartina alterniflora plugs for transplanting. Mudflats in the protected canals were populated by numerous wading birds, and the mudflats of the delta terraces in the bay were covered with shorebirds. One of the biggest gators I’ve seen was lazily sunning itself unconcerned as we passed.

Figure 11. An army of black-necked stilts (and one avocet).

Figure 11. An army of black-necked stilts (and one avocet).

Figure 12. Mudflats between delta terraces were full of shorebirds.
Figure 12. Mudflats between delta terraces were full of shorebirds.
Figure 13. Big gator on mudflat between delta terraces.

Figure 13. Big gator on mudflat between delta terraces.

We returned to the dredge site at 11:00 and went out into the pond to inspect and fix containment in Cell 1 and Cell 4. The birds were back on the mudflat in Cell 4 and had brought friends. Regardless of our activities, the usually shy birds kept returning to the mudflat.

Figure 14. The birds on the mudflat in Cell 4 included, left to right, black-necked stilts, short-billed dowitcher, common moorhen, more stilts, blue-winged teal, dowitcher, stilt, mixed group of long- and short-billed dowitchers, stilts.

Figure 14. The birds on the mudflat in Cell 4 included, left to right, black-necked stilts, short-billed dowitcher, common moorhen, more stilts, blue-winged teal, dowitcher, stilt, mixed group of long- and short-billed dowitchers, stilts.

We paddled the canoe out and fixed the north end of containment #1 first. I tried but couldn’t get the plywood pounded through the edge of the patens marsh. Timmy cut the root mat with a knife and was successful in closing the gap that we had left on initial installation. We paddled to the other end of containment #1 and Timmy pulled the canoe over into the outer pond so we could get on the outside of containment #4c. We identified another leak and Timmy pushed another plywood plug into place.

We got out on the marsh and walked around the south perimeter of the pond admiring the fluid mud that was an inch below marsh level (ML). Closer inspection revealed a high concentration of Chironomid larvae or 1/4-inch long “bloodworms” churning the surface of the fluid mud. No wonder the birds were so persistent in returning! It was a bird buffet! Normally on the bottom of a waterway, I’m guessing the midge larvae were transported from the canal in the dredge effluent.

Figure 15. The fluid mud was covered with millions of  "bloodworms" or larvae of a chironomid midge.

Figure 15. The fluid mud was covered with millions of "bloodworms" or larvae of a chironomid midge.

By the time we got back to the dredge it was 12:30 and already 85°. March 1st and 85°. Ugh.
We cranked up the dredge and got to work. A few minutes into dredging and a Frogco boat and airboat came up and down the canal, and we had to lower the right traveling cable each time for them to pass. They were visiting the access point to the south part of the Coles Bayou area which is north of the dredge site. After about an hour of dredging with no clogs or problems, I left Timmy dredging to go to the pond to watch where mud went.

Fighting the wind, I paddled around to look for leaks and watch the outflow. The containment was working well enough to have the mud level in Cell 4 at marsh level while the pond level was at -3 ML. The higher water level was backflowing over containment 5b into Cell 5, but not going anywhere from there. However, it was leaking through the marsh to the east of containment 4a, through containment 4a where two bundles of reeds met, through a few of the joints in containment 4b, a little through the west end of 4b, and a walk over the marsh showed a big leak through containment 4c into the outer pond. Cell 4 was completely full of fluid mud to marsh level with a large new delta filling up the eastern end of the cell, completely covering the previous delta.

It took two trips to bring enough poles and bundles for repairs and to reinforce 5b so I could walk across it without sinking into the mud. Once across, an inspection of the south end of Cell 5 confirmed no leakage, and the southwest side of Cell 4 showed that no mud was making it past the delta to cross 4d. Back on the north side, I used a bundle to patch the leak in 4a. In the heat and fighting the wind, I was pretty tired, so was happy to beach the canoe and return to the dredge. We finally shut it down around 4pm after 3 hours of pumping.

Figure 16. Cell 4 was filled to marsh level with fluid mud, backflowing into Cell 5, and making another delta mound above marsh level.

Figure 16. Cell 4 was filled to marsh level with fluid mud, backflowing into Cell 5, and making another delta mound above marsh level.

Figure 17. Estimated status of fill in the 5 experimental cells as of March 2, 2012. Green lines are completed containment, orange lines are planned containment, white dots are approximate locations of pvc marker poles.

Figure 17. Estimated status of fill in the 5 experimental cells as of March 2, 2012. Green lines are completed containment, orange lines are planned containment, white dots are approximate locations of pvc marker poles.

Test Cell  After shutting down the dredge, we rode down to the test cell. Two alligators were reluctant to leave the bank when we pulled up, but jumped in just as I was reaching for a paddle to give them more motivation.

Figure 18. Timmy planting Spartina along the inside of the test cell containment.

Figure 18. Timmy planting Spartina along the inside of the test cell containment.

Timmy pulled plants this morning to add to the containment of the site. The Spartina alterniflora he had planted last year on the inside of the containment as an experiment had performed as expected, reinforcing the roseaucane containment and spreading out into the new mud. He wanted to finish lining the rest of the containment.

There was three-square spreading from the marsh edge, spikerush greening up all over, and new grass sprouting in the several places in the center. We are eager to bring the dredge back to this area when the LSU area is filled to add more sediment and extend the fill.

 

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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