April 11, 2013 – High Water Dredging in C3

Dredge and Rainey Report
High Water Dredging in C3

April 11, 2013

Summary of accomplishments:

  • Total time dredging this week into Cell 3: 10.75 hours
  • Total time dredging into Cell 3: 75 hours
  • Total time at experimental site: 221.5 hours
  • Spartina patens and Scirpus olneyi are spreading well

Impediments: high water in canal and pond, very windy conditions

Summary:

This report can be downloaded in PDF file format by clicking the Dredge and Rainey Report, High Water Dredging in C3 hyperlink.

Last week, April 1-3, water in the marsh creation site was still too low (3” below marsh level) to dredge, so we worked in the apartment. We finished tiling the floor and Timmy cased in the door. We started installed the plumbing and started on assembling the shower, but it was more complicated than we had anticipated and Timmy finished it after I left.

This week, the expected storm front was due later in the week, which put the pre-storm high wind and water at the beginning of the week, and was sustained long enough to bring water into the marsh and ponds.

Tuesday, April 9

Karen arrived at the Paul J Rainey Wildlife Sanctuary at 7:45 am, and went straight to the dredge, where Timmy was already dredging. The day was warm, overcast, and misty. I went to the pond to document the beginning conditions, and was greeted by 12 Blue-winged Teal, 15 Black-necked Stilts, 18 yellow-legs and an Eastern Kingbird in Cell 3as I stepped up on the boardwalk. When they spotted me, they lifted to settle just a little further away.

I found the pond water level at +1″ ML (1 inch above Marsh Level). No sediment plume was evident directly escaping the containment, but I could see a plume of finer material filtering through the marsh to Cell 4 then back into Cell 2. I headed to the headquarters to unload my gear, then returned to help with the dredging.

Soon after I settled on the dredge, at 9:25, we stopped to rearrange discharge hose. Timmy had been dredging for over an hour, and we like to move the outfall often when we are in a shallow receiving basin. Cell 3 only needs about 4” of fill at the north end to be complete. When we started, the 1/3-acre cell was 10-12 inches deep. The south end has been brought to marsh level or above, and the marsh grass is spreading into it very rapidly.

I walked around Cell 3 to untie the east pull rope, and Timmy pulled the hose into a new position by the walkway on the west side of the cell. The length of hose in the cell had been buried in dried mud and was still a bit hard to pull. Plus, a portion of the hose in the pond is hard hose and doesn’t bend, which caused the flex hose to kink when we tried to pull it in different positions. We tried looping a rope around the hard section to pull it loose but it wouldn’t budge.

Figure 1. Water level was at +1" ML, with Blue-winged Teal in the foreground and Black-necked Stilts in the back.

Figure 1. Water level was at +1" ML, with Blue-winged Teal in the foreground and Black-necked Stilts in the back.

We were back on the dredge by 10:00. I found a 3-ft long snakeskin entwined through the floor grate, and as we were starting the dredge saw small snake on the ladder across from us. Both were non-venomous garter snakes. As we dredged, we noticed even more snakes crossing the canal. There were more snakes than Timmy had seen in years. The dredge seems to be developing its own ecosystem, with ants, flies, wasps, lizards and now snakes. As long as they don’t have big front teeth, I’m good.

Figure 2. The latest dredge fashion.

Figure 2. The latest dredge fashion.

I dredged while Timmy went to shore to watch the hose. After only 20 minutes, I noticed the pump pressure dropped, which usually indicates the pump is clogged. I stopped to clear it, but there was nothing in it. I tried to resume, but the pressure was still too low.

Timmy reappeared to report that the hose had kinked right where the flex joined the hard hose and nothing was coming through. We would have to pull out the hard sections to be able to appropriately direct the outfall.

Timmy dropped me off at the dredge to get my boat, and left in the flat boat to trade it for the airboat. I went back to the pond and tried to take the hose apart, but I didn’t have a hammer to break the corrosion loose. I collected some boards to use for braces and levers, walked around the cell to loosen ropes, and it wasn’t long before Timmy arrived with the airboat and tools.

Figure 3. Timmy arriving with the airboat, cruising along on the other side of Cell 4.

Figure 3. Timmy arriving with the airboat, cruising along on the other side of Cell 4.

It took some effort to get the hose connections apart, especially the ones that had been submerged in the pond. We disconnected a joint close to the pond, and Timmy tied the hose coming from the pond to the airboat, and pulled the hose up onto the marsh far enough that we could get to the next joint. It took several airboat pulls to take out both hard sections, and to reconnect the flex hoses. With Timmy on the walkway and me in the marsh, we pulled the hose back into the pond until the ends matched again and it could be reconnected to the dredge. The pull-rope broke once, but we have lots of rope on hand and slipped another one onto the hose to finish pulling it in place.

Figure 4. Timmy on the walkway pulling the hose back into the pond.

Figure 4. Timmy on the walkway pulling the hose back into the pond.

With that done, we were back on the dredge for lunch and to start dredging again at12:45. The day was still overcast and had warmed to 80°, and it was windy with gusts to 25 mph. There weren’t too many birds trying to fight the wind. A Northern Harrier (marshhawk) teetered across the sky scattering a flock of Red-winged Blackbirds from the reeds. We watched as a pair of Eastern Kingbirds inspected a possible nest site in the bush next to us.

Figure 5. Eastern Kingbird checking out a new nest site.

Figure 5. Eastern Kingbird checking out a new nest site.

After a swing across the canal, Timmy used the Avocet to move the right traveling cable and went to the pond. Soon after, the pump acted clogged again but wasn’t, and he returned to say that the hose had kinked when he was trying to move it.

We checked weather radar and there was scattered rain all around us, generating wind gusts to 19 mph. Despite the conditions, the dredging was rather uneventful and we stopped at 5:00.

We went to the pond and found that the water level had risen in the pond to +3” ML and we could see some sediment at the surface, so we knew we had moved a lot of material. There was a definite color difference between Cell 3 and Cell 2, so we are fairly certain that we are not losing anything through the containment, but that it is filtering through the marsh.

Figure 6. At the end of the day, we could see sediment at the surface (chunks in front of Timmy) and a color difference of the water between Cell 3 on the right and Cell 2 on the left. The waterlevel was up to +3" ML.

Figure 6. At the end of the day, we could see sediment at the surface (chunks in front of Timmy) and a color difference of the water between Cell 3 on the right and Cell 2 on the left. The waterlevel was up to +3" ML.

The ride back to the headquarters was the worst part of the day. The south wind had whipped the water in the north-south canal into rolling waves, and we were battered by gusty head-winds. We saw a raccoon up in an isolated tree, and thought it was because of high water, but when we circled back to get a good look, we saw an alligator camped out at the base of the tree. Neither one would move when we approached. I wish the raccoon luck!

Figure 7. This raccoon (also on right indicated by a black arrow) was in an isolated tree with a problem. A large gator (white arrow) was waiting patiently at the base of the tree, and there was nowhere to run.

Figure 7. This raccoon (also on right indicated by a black arrow) was in an isolated tree with a problem. A large gator (white arrow) was waiting patiently at the base of the tree, and there was nowhere to run.

Wednesday, April 10

The water had come up in the yard even more by dawn. The house was on an island and the water was up to the bottom step at the front door. As we left to head to the dredge, we had to be careful to make no wake.

Figure 8. Water level had risen to the bottom of the front steps and under the front of the camp.

Figure 8. Water level had risen to the bottom of the front steps and under the front of the camp.

Figure 9. The 4-wheeler was parked on a high spot, and there was no break between the canal and the dock.

Figure 9. The 4-wheeler was parked on a high spot, and there was no break between the canal and the dock.

Figure 10. We live in Waterworld.

Figure 10. We live in Waterworld.

We made it to the restoration area around 9:00. The canal water level was at 3 feet above sea level, or 2 feet higher than normal and was overflowing the bank. We were pleased to see the salinity was at an intermediate marsh 5.53 ppm. We parked the boats on top of the bank instead of against it and waded up to the levee.

The water level in the pond was 8 inches higher than normal marsh level, flooding the marsh. All of the containment was under water as were most of the walkways in Cell 4.

Figure 11. We tied the boats on top of the bank (left) and saw that the containment and Cell 4 walkways were underwater.

Figure 11. We tied the boats on top of the bank (left) and saw that the containment and Cell 4 walkways were underwater.

To dredge with the water so high, we stood a chance of losing lighter dredge material over the containment or into the marsh, but reasoned that the heavier stuff would stay within the cell boundaries. To make this more likely, we wanted to move the outfall to the far northeast side of the cell. The water was too high to walk around through the marsh, so we used the airboat to access the rope to pull the hose as far as it would go.

Figure 12. The trail around the pond to access the rope we use to pull the hose was flooded too deep for our boots. We used the airboat to get around.

Figure 12. The trail around the pond to access the rope we use to pull the hose was flooded too deep for our boots. We used the airboat to get around.

The conditions when we started dredging at 10:00 was an overcast sky, 80°, and windy. We observed wildlife all around with alligator gar slapping the surface, White Pelicans soaring aloft, White-faced Ibis and shorebirds riding the wind, and a 4 ft speckled kingsnake crossed the canal. The current past the dredge continued to flow into the canal and marsh bringing swirling muddy water from Vermilion Bay. We stopped after two hours of dredging to move the hose again further north around a marsh island. The water level had increased another inch to +9″ ML.

We got back to the dredge about 12:30, and Timmy left to go to the boat landing and Maxie Pierce’s Grocery while I continued to dredge. I entertained myself while pushing buttons to operate the pump by watching wildlife, scoop-netting for small critters on the side of the dredge, checking weather, answering emails on my phone, trying to take self-portraits, and trying to make our indicator float sink (when you hit good mud, it makes the hose heavy and the white float can’t quite keep the hose up). Several more snakes crossed the canal, and the kingbirds were active in the trees.

Figure 13. One of the many garter snakes that crossed the canal by the dredge (left), and almost sinking the white float with good heavy mud (right).

Figure 13. One of the many garter snakes that crossed the canal by the dredge (left), and almost sinking the white float with good heavy mud (right).

Figure 14. Timmy washing the pump at the end of the day.

Figure 14. Timmy washing the pump at the end of the day.

Two and a half hours later, the multiple swings of the dredge had moved us to the limit of the length of hose in the canal. Timmy returned just as I was finishing up at 3:15 and he helped me shut the system down. We would have to add hose or start back the other way when we dredge next.

We went to the pond, and found that the water level had come up more, to roughly 10” above marsh level. None of the walkways in Cell 4 were above water, and the wind generated waves in the short reach across Cell 3 were splashing up on the main walkway at the containment between Cell 3 and 2. Timmy adjusted the ropes to the outfall and we secured the airboat.

Figure 15. At +10" ML, none of the containment or walkways in Cell 4 (at the top of the frame) are above water, and the waves are splashing onto the main walkway.

Figure 15. At +10" ML, none of the containment or walkways in Cell 4 (at the top of the frame) are above water, and the waves are splashing onto the main walkway.

When we got back to headquarters, we discovered that the backyard had become a duckpond. With the wind whipping the waterways into sloshing wave pools, our flooded yard was a calm spot in the storm. 5 Blue-winged Teal, a squadron of Lesser Yellow-legs, Snowy Egrets, Killdeer, grackles and black birds were enjoying themselves just outside our back window. Martins, Barn Swallows and Tree Swallows swooped overhead enjoying the party. Even a pair of Black-bellied Whistling Ducks stopped by briefly.

Figure 16. The backyard had turned into a duck-pond. In this picture, left to right: two Blue-winged Teal, Lesser Yellow-legs, Two Red-winged Blackbirds, Killdeer, Blue-winged Teal, and the tail of a Boat-tailed Grackle.

Figure 16. The backyard had turned into a duck-pond. In this picture, left to right: two Blue-winged Teal, Lesser Yellow-legs, Two Red-winged Blackbirds, Killdeer, Blue-winged Teal, and the tail of a Boat-tailed Grackle.

Figure 17. Lesser Yellow-legs.

Figure 17. Lesser Yellow-legs.

Thursday, April 11

It was more of the same the next day, but with more birds stopping by to enjoy the relative shelter of the flooded yard. Most of the birds traveled in pairs, or were working on the pair bond. We got to watch quite a few rituals being carried out. The teal would glide in to landing then pair up and gabble at each other. The Black-necked Stilts would preen, then the female would drop her head and periodically turn as the male would make a long-legged circle tight around her, and they would both preen again. Yellow-legs chased each other or stalked off alone. There was a lot of “twitterpating” going on…

Figure 18. Two pair of Blue-winged Teal just outside our window.

Figure 18. Two pair of Blue-winged Teal just outside our window.

Figure 19. In some kind of courtship ritual, the female (browner on the right) kept a lowered head stance and tried to keep herself broadside as the male (on the left) took big steps in a tight circle around her.

Figure 19. In some kind of courtship ritual, the female (browner on the right) kept a lowered head stance and tried to keep herself broadside as the male (on the left) took big steps in a tight circle around her.

We had to wade between buildings to get work done, keeping an eye on the large gator cruising along the expanded canal edge. We both had to leave today, and a front was moving in from the west. Timmy left while I was putting together what we hoped would act as a hose splitter out of ABS plastic and hose fittings.

I ran by the pond, of course, on my way out, to find that the water was now almost a foot above marsh level. I would have to wait until the next time to see how much material we had added.

Figure 20. Wading between buildings, and watching the large gator pass the front steps.

Figure 20. Wading between buildings, and watching the large gator pass the front steps.

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
225-768-0921x202 office, kwestphal@audubon.org
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