Delta Dispatches: Deltas 101 – Back to Basics

On today’s show David Muth, Director of Gulf Restoration, National Wildlife Federation stops by to talk with Jacques & Simone about the importance of restoration of the Mississippi River Delta. On the second half the show, Dr. Alex Kolker, Associate Professor at the Louisiana Universities Marine Consortium joins the program to talk with Simone & Jacques about subsidence, sediment diversion and even potholes! Listen Now

Below is a transcript of this week's Delta Dispatches Podcast. Listen to the full recording here or subscribe to our feed in iTunes and Google Play.

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Show Transcript

Jacques: Hello, this is Jacques Hebert. You're listening to Delta Dispatches. We're discussing Louisiana's coast, it's people, wildlife and jobs and why restoring it matters.

Simone: And this is Simone Maloz. We're back together.

Jacques: Reunited and it feels so good.

Simone: You my peanut butter. I'm your jelly.

Jacques: How's it been without me, Simone?

Simone: I missed you terribly. I'm glad you got a vacation, though. Did you go on a vacation or like was that summer camp or something?

Jacques: It was a college reunion up at Dartmouth in New Hampshire.

Simone: Like you like canoeing …

Jacques: So, there's a lot of canoeing, a lot of outdoors, so it's college, summer camp, but it was a good experience, and I heard your episode with Robert, Dr. Robert Twilley and Pepper.

Simone: It was great. It was great. I could have used a whole other show. I was very nervous to be one without you but they had, Robert Twilley's an old friend, and Pepper is certainly a new friend. I saw some video from the event, the bycatch event, so it looked like it turned out nice and Dr. Alicia Renfro who's been on the show with us before said the food was really good.

Jacques: Yeah. I wasn't there unfortunately, but I'd like to taste some of those recipes sometime, so I heard you had a big day in Terrebonne this week.

Simone: We did. Terrebonne hosted their inaugural coastal day, and this was really the brainchild of parish president Gordie Dove and the levee district executive director Reggie Dupree who used to be a state senator and is actually the father of the CPRA. He was the one who put the legislation together and they just had this idea to put on a coastal day and to get as much information out there as possible about some of the protection that they have in store and then some of the restoration projects, but they brought levee district equipment in, like their boats and everything. It was really amazing, so hats off to them for a really great event. They had the vision for it and their staff executed it really, really nicely. They had some good ink as some columnist people would say on that as well, so kudos to them for a good coastal day.

Jacques: Yeah, that's great and I heard there was a really good turn out and it's definitely something that other parishes could emulate.

Simone: Absolutely. We're already looking forward to next year. They think they had over 700 people come through the Home of Terrebonne Civic Center, so yeah, a great, great turn out, especially considering they had a tropical storm.

Jacques: Yeah, from Audubon's perspective, we've been watching it really closely because while Cindy may have not had the kind of, thankfully, the effects kind of on people and flooding, it definitely did bring some storm surge across beaches at the height of nesting season, so there's been some coverage and stories that have been done showing that it wiped out a lot of the nesting birds who weren't able to fly away from Texas to Florida, so our staff are out kind of monitoring the effects and there are also going to be volunteer opportunities this weekend to go out to Grand Isle and other places to help these birds recover and so if you want to find out more you can go to to volunteer.

Simone: Great. Great. Also on the Mississippi River Delta website is still the information about the GOMESA and the administration's being removed from the administration's budget so you want to remind folks about that.

Jacques: Yeah, you can just go to and make sure that you let your legislators know, your congressman, your senators, that GOMESA's important. It's worth protecting and that you vocalize your support for it.

Simone: Yeah, just a reminder. We talk about this a lot on the show but it's been the past couple of years through previous administrations, the threat has been to take away GOMESA funds which is dedicated here in Louisiana to coastal restoration and protection efforts, so we had the vision before that came online that we would dedicate that to coastal resources and so, that's a real threat that that could take away from resources that could be allocated to our coast. So who are we talking to today?

Jacques: We've got some great guests, good colleagues and friends on the show. First up we have David Muth with the National Wildlife Federation. David is the director of gulf restoration for National Wildlife Federation. He's also been working in Louisiana and on coastal issues for quite a while, previously with the Jean Lafitte National Park Service and where he was for 30 years, so we're going to talk to him a little bit about that, but also …

Simone: He's a bird dude, too.

Jacques: He is pre-eminent bird expert in the state and I'm not kidding. And we're also going to talk to him about his current role and what he's been doing to advocate for large scale restoration, particularly here is Louisiana but also across the gulf.

Simone: Yeah, we have another friend coming in the studio, too. Alex Kolker, and Alex works at LUMCON and he has some information about sea level rise and subsidence. David's going to talk about the delta and hopefully Alex will talk about what's happening to the delta now.

Jacques: Yeah, so we're kind of going back to the basics today with the show. We're discussing deltas since we are Delta Dispatches and we're part of the Restore the Mississippi River Delta Coalition, so what are deltas, how do they form, why is the Mississippi River Delta so important, and then what are some of the challenges facing our current delta and then also, of course, restoration opportunities.

Simone: Great. Well, let's get to it. Welcome to the show.

David: Thank you, Simone.

Simone: Mr. David Muth. M-U-T-H. Muth.

David: That's very good, Simone.

Simone: We just had a pronunciation lesson and my name Simone Maloz, like people don't screw that up, David. David, you grew up just on the other street, right? Just one street down from me.

David: I did, in Metairie, that's correct.

Simone: You went to the old St. Catherine.

David: I did.

Simone: And then you went to … where you went to high school, David?

David: I went to Rummel High School in Metairie.

Simone: Yes, very nice. Very nice. So, David, we've worked together for a long time, but why don't you tell folks a little bit about yourself and what you used to do and what you do now?

David: Well, as we've said, I'm a native of the New Orleans region. I've spent my whole life here in New Orleans and spending time in wetlands and in other areas of southeast Louisiana, and I was very lucky that 30 years ago when Jean Lafitte National Historical Park and Preserve was being formed, I got a job there, and managed to have an entire career there, working on issues and on the kinds of things that really interested me which included the history and the natural history and the culture of southeast Louisiana, of the delta region.

Simone: And then you joined the campaign?

David: I did. I retired from the federal government and I joined the campaign in the beginning of 2011, working for the National Wildlife Federation.

Simone: And what do you do now?

David: I'm still working for the National Wildlife Federation …

Simone: What's your title?

David: I'm the director …

Simone: Man, he's got to pull stuff out of him, huh?

David: I'm the Director for Gulf Restoration, so I, in addition to the work here in coastal Louisiana, because of this massive influx of interest and resources that are coming to the entire gulf region, we work in all five gulf states on issues about restoration.

Simone: Yeah. So let's talk about our state. Let's talk about the delta a little bit. I've been with you several times before when we've brought folks down and they needed a crash course I coastal 101 on how we even got here in the first place and about America's great delta and how we got there and then what's happening to it now, so let's start there, living on a delta, right?

David: We're living on a delta. We're on one of the largest deltas in the world, depending on how you measure it, but certainly one of the top 10 deltas in the world in terms of size, and like many, many deltas, our main city and our infrastructure is all about that connection between the interior of a continent, that it's great river gives you to the ocean, and that's why New Orleans is here, that's why many of our other ports along the Louisiana coast are here.

Jacques: And David, we've talked about this on previous episodes, but basically the delta as we know it now isn't necessarily the delta that's been over time, so can you talk a little bit about the history of the Mississippi River Delta, maybe some big changes, how it shifted and kind of explain the deltate process that has led to what we have now in terms of the Mississippi River Delta.

David: Sure, deltas are not static. They don't stay the same. They're all about change and the reason is, is that they're, in terms of geological processes, they're alive. They're changing all the time, and because they react so closely to what the sea is doing, in our case, when sea level was much lower during the ice age, which wasn't that long ago, 14,000 years ago, there was no delta here. There was a big valley that went all the way up into Missouri and Illinois, but once sea level reached its, pretty much, current stand, the Mississippi River began filling in the valley and eventually it filled in the valley and it got to the gulf and it started building deltas out onto the continental shelf, and it would build one delta then it would take a short cut to the sea and build a new delta and the old delta would begin to erode and to sink and would become an estuary.

 And that's really been the process that we've been seeing for thousands of years in Louisiana. The city of New Orleans, the city of Houma, the city of Thibodeaux, the suburbs of Baton Rouge, much of where we live is on that delta, and I think a lot of people don't really think about that but we're on a delta that's been tamed.

Jacques: Right, and by tamed you mean we have the Mississippi River levees that's kind of kept the Mississippi River in place and then there have been other effects as a result of that, mainly land loss and we're going to talk a little bit about that with Dr. Alex Kolker when he's here, but we're going to dig into this topic a little bit more with the Mississippi River Delta, kind of why it's so important, not just to our region but to the world when we come back from the break. You're here with Delta Dispatches and we have David Muth on the shoe. We'll be back right after the break.

Jacques: Hello. You're listening to Delta Dispatches. We're discussing Louisiana's coast, it's people, wildlife and jobs and why restoring it matters. We are here with David Muth with the National Wildlife Federation. Before the break, David, you had mentioned that kind of the delta, the Mississippi River Delta, as we know it has been kind of stuck in place by the Mississippi River levees. So, let's talk a little bit. What is the state of the Mississippi River Delta currently?

David: Well, it's in pretty sad shape. We, as the people who settled this delta made a decision a long time ago that we were going to do our best to tame the river, and we were very successful at that. We leveed it. We closed off all of the distributary channels and we channelized the navigation system, and the result of that is that a system that used to be sustained by the spring overflow, by the distribution of sediments and fresh water from the river has really been left open to salt water, to the Gulf of Mexico. That makes great estuaries and that's one of the reasons we've been so productive in terms of seafood for the last hundred years, but it's come at a price and the price is the total amount of land that's available.

Simone: So, David, is there hope to returning to a healthy delta and then I understand what you're saying about seafood. That's a really good point, but is there hope in returning it to more natural and the way that is was?

David: There absolutely is hope and we have something that many, many, many coastal areas of the world don't have, coastal areas that are watching rising sea level. We have a river full of sediment and we just have to figure out how to tap that sediment. The state master plan has a series of projects that are envisioned over the next 50 years that will begin to substantially increase the amount of sediment that we get instead of putting it out over the edge of the continental shelf or picking up in dredges that we actually put into wetlands to sustain and build new wetlands.

Jacques: And you know, our organization, of course, we're active proponents and believers in sediment diversion and we believe they're crucial as you said, so let's talk about specifics. The mid-Barataria sediment diversion is the furthest along in terms of implementation. Tell us a little bit about this diversion, why it's so important and what is the status of it?

David: Yeah, so this is one of those diversion ideas that's been on the books for at least 30 years because if you look at a map of Louisiana, it's pretty obvious, you have the upper Barataria Basin north of Barataria Bay. The marsh has been collapsing. It's been disappearing, and the river's right there. So this has been kicked around in every planning document for the last 30 years. The great news is that we are on the verge. The state has begun the formal process of getting permits, of doing the environmental impact statement to go to construction of the mid-Barataria diversion and it's going to be a really major change in the way we manage the river. It's going to be 75,000 cubic feet per second which is one of those terms people throw around, but to put that in perspective, when it's flowing at full capacity and it'll only do that during big flood years, but when it's flowing at full capacity, it'll be one of the biggest rivers in North America.

Simone: So, David, they are moving along in that process and they're close to doing some scoping meetings within EIS, so we've had Rudy Simoneaux and some of the state managers, so we'll come back to that when it gets closer to the event, but maybe explain a little bit of that process about EIS and scoping meetings, anything like that. There's several layers that you have to get through, correct?

David: There are a lot of layers that we still have to get through. We have to get permits from the US Army Corps of Engineers to build a diversion through the river levees and through the back levee, and in order to issue that permit the Corps of Engineers has to do an environmental impact statement and that's got to analyze not just the footprint of that project but the consequences of the project to the ecosystem at large and to human communities at large, so that's the process that we're beginning now.

Jacques: And David, I want to kind of shift back a little bit, so I mean, obviously sediment diversions are hugely important. We just talked a little bit about the mid-Barataria sediment. There are others in the coastal master plan that we focus on and folks can go to our website or CPRE's website to learn more, but we often get the question why don't you just move, right? Sea levels are rising. You have this terrible land loss crisis. Can you talk a little bit about why the Mississippi River Delta is so important, I mean maybe was historically to Native Americans, to European settlers, and even today remains so important, not just to the people who live here but to that nation.

David: Well, it's important to be near the resource, so whether that resource is the navigation opportunities of having a city and a major port system near the mouth of a river that drains a huge part of a continent, so that you can take the raw materials that come from the interior of the continent, put them on ships and send them overseas, you have to have a place to do that, and the farther inland you do that, the more expensive it is. We also have the wildlife resources and the seafood resources that if you're going to take advantage of those resources, enjoy those resources, you have to be close to them, and finally, we happen to be sitting in the cradle of oil and gas production and refining in North America and so the infrastructure to make that work is here, and if you have to move it, the price is going to go up.

Simone: By a little bit.

David: By quite a bit.

Simone: David, you mentioned earlier, you work across the gulf. You work, you obviously have the pleasure of being a Louisiana native and living here now, but you work across the gulf, so how different or not different are the other states, the challenges that they face versus Louisiana. Are some the same? Are some different? Tell us a little bit about that.

David: There's a lot of overlap in those challenges. There's a lot of things that they face in coastal wetlands around the gulf from the Everglades to the Rio Grande Valley that are very similar, but at the same time, our position on a delta which has a very high subsidence rate has much bigger implications, and one of the reasons that Louisiana has reached the point of having a master plan and a master planning process is because frankly, we've been suffering the consequences more acutely than many other areas of the gulf. But there are areas of the gulf with very similar problems and similar amounts of planning and effort that are going into restoration including the Everglades. So it's a mixed bag.

Jacques: Right, and I mean, as much as our situation is severe and dire, I mean, we also need to pat ourselves on the back a little bit in terms of how far we've come, how comprehensive our plan is and we've focused on the master plan a lot on this show and had Brent Haas from CPRE and others on, so it is a huge accomplishment and there are reasons to be hopeful despite the situation we face. David, I have to ask you this question because Simone and I like to keep it fun in addition to covering the substance, so our fun question for the day for you is what is your favorite bird?

David: Oh, I don't have a favorite bird. My favorite bird is the next one that I see that I hadn't seen before, so it's my next life bird.

Jacques: You see, I feel like that's the answer that the real birding experts have. It's very similar to what Dr. Eric Johnson with Audubon Louisiana said. We asked him what's your favorite bird, he said "Whatever one I'm looking at," so it's like picking among children. Well, David, we really appreciate your being on the show. We hope to have you back soon. You're not going to go too far, so we'll have on for an update on mid-Barataria and some other topics, but for now, thank you and when we come back from the break, we're going to have Dr. Alex Kolker and we're going to dig into some of the topics, some of the challenges that face our delta, particularly subsidence and talking a little bit more about the opportunities to restore the great Mississippi River Delta. You're listening to Delta Dispatches and we'll be back after the break.

Jacques: Hello. You're listening to Delta Dispatches. We're discussing Louisiana's coast, it's people, wildlife and jobs and why restoring it matters. We're back with Dr. Alex Kolker. Dr. Kolker is currently …

Simone: And he has, Alex has a guest.

Jacques: A special guest.

Simone: Don't be rude.

Jacques: Sorry.

Alex: And my guest here is Dupree, who is a Zydeco retriever.

Simone: Nice.

Jacques: And you and Dupree were just out in the marshes.

Alex: We were out at Caernarvon, yes.

Simone: Is she a marsh dog?

Alex: He is a marsh dog. Exactly.

Simone: Well, Jacques was hoping to get the folks on who make the nutria treats.

Alex: Oh, yeah. He will do some promotion for that.

Jacques: Oh, good. He's a fan of the nutria treats. That's great.

Alex: He is a fan.

Simone: Alex thinks Dupree is a little or medium sized dog. No, no, no.

Jacques: He's pretty big.

Simone: He's a healthy dog. Healthy dog. Welcome and thank you for coming to the studio.

Alex: Thank you.

Simone: We're glad to have you.

Alex: It's great to be here today. Absolutely.

Simone: It just happened to be that you were coming from Caernarvon.

Alex: I was coming from Caernarvon so thanks for the invite, but I was out there.

Simone: Great. Great. We're going to talk about Caernarvon in a little but we want to get to know you some so you're based down at LUMCON in Cocodrie.

Alex: Right, so …

Simone: You got to tell people what LUMCON is. You may have to tell them where Cocodrie is.

Alex: All right. So LUMCON, we are the Louisiana Universities Marine Consortium. We are effectively the marine lab for the state of Louisiana, so we are a marine lab and we're down in Cocodrie which is about 45 minutes south of Houma and the lab, we do all kinds of marine science, so I'm a coastal geologist, but we have biologists, fisheries people. We got actually a couple of new fisheries people that just joined us and a new environmental chemist that joined us as well.

Simone: We had Dr. Twilley on last week and he told me that that was his, when he came to Louisiana, that's where his interview was, that he had to drive down to LUMCON and they had just built LUMCON.

Alex: And you know, he's actually has told me that's the reason I came to Louisiana.

Simone: Yeah.

Alex: He has told me that. It is a fantastic facility. In part, it's great because you can do fantastic scientific research and you're right out in the middle of the marsh.

Simone: Absolutely. Yes.

Alex: And our boats have access to the open Gulf of Mexico.

Simone: Definitely.

Alex: So you can take samples and analyze environmental samples in near real time and do experiments that you just couldn't do at a campus at Baton Rouge or New Orleans.

Simone: Absolutely. Ooh, and you have a beautiful building down there and we were talking about how well it was constructed to withstand hurricanes.

Alex: Yeah, so that building has withstood Andrew and some before my time. I can guarantee you that, but it has withstood a number of hurricanes. Now we are close to the water and we are concerned about rising waters and rising sea levels.

Simone: You more have problems with water in the parking lot and access to the building itself.

Alex: Yeah. I mean we have problems. I would almost say the problems are more complicated on a sunny day than a hurricane. I mean, it's actually a very strong robust building that can survive a hurricane. Our bigger concern I think in the near term is access and when can you get, can the delivery people get trucks up to the building and those kinds of questions.

Simone: Right. In fact, you all, I think, when I had a meeting at LUMCON I heard that you all had 3,000 school children come through the building.

Alex: I think maybe 5,000.

Simone: Five thousand. Yeah.

Alex: It's a lot.

Simone: You bring Dupree to entertain them? Is that …

Alex: Unfortunately, he doesn't come down as often as he would like, but we do get, you know, as someone, as our Ed person says, we have K to gray. We have everything from K to 12 students, university students, graduate students, researchers coming over and seniors groups as well. Adult Ed and seniors groups and teacher trainings, so you name it. The age, the section of the population, we work with students from across the spectrum, and it's really one of the, in my view, it's one of the rewarding things about working there because we can work with, talk to so many different kinds of people about coastal Louisiana and the interesting things about it.

Simone: And they're interested.

Jacques: So, Dr. Kolker, you as a geologist study subsidence quite a bit. So can you explain to the average person that may not know what is subsidence?

Alex: Subsidence is the land sinking, so it's just the land lowering is basically what subsidence is.

Simone: Is that your first day of undergrad was "Subsidence is when the land sinks. End of class."

Jacques: You passed Geology 101 but it's a big problem here, correct?

Alex: It's a big issue here in Louisiana. We're sinking, and as scientists, of course, one of the questions that we have is how fast are we sinking, why are we sinking and where are we sinking because we're not sinking the same rate all across the coast and those rates probably are not the same, they might change over time, too.

Jacques: And we were talking with David Muth earlier about how a delta's formed and part of that subsidence is actually that we're living on a delta that different parts are sinking.

Alex: Absolutely, so the muckier, more organic soils tend to sink faster because they just don't have the robust strength that a solid mineral soil that might be the river sands. River sands ten to sink relatively slowly whereas organic, mucky, marshy stuff tends to sink much quicker, and areas where the sediment is really thick like say at the bird's foot, at the mouth of the river, those places tend to sink relatively quickly and areas that have relatively shallow marshes, those areas tend to sink a little slower.

Simone: So tell us about subsidence and how that relates to relative sea level rise and how do those work together in a way here for Louisiana.

Alex: So we talk, the technical term is relative sea level rise. The short story is the water can go up for two reasons, right? It can either go up because the land sinks or it can go up because the water level raises, and of course, we have to deal with both here in south Louisiana. We're sinking as we said, and of course, global sea levels are rising. Global sea levels are going up, so you put the combination of those two together and that's what scientists call relative sea level rise, but to your average person or to a lot of water level gauges that just shows the water going up.

Jacques: And there was a recent study that came out by the Geological Society of America, a new subsidence map for coastal Louisiana, it showed that rates were pretty high in terms of subsidence.

Alex: I will say that that map, the data analysis and the patterns that they showed were beautiful. One thing I would say is the overall magnitude of that was actually not all that shocking. Those rates were about a centimeter a year, I think coast-wide which is a pretty similar average to what we've been saying for a while. What was really to me as a scientist, what was new about that, was the patterns and the level of resolution that they had, that they had basically analyzed something close to 300 stations.

Jacques: Wow.

Alex: And they were able to show, for example, higher subsidence in areas around the Atchafalaya River which many people thought was a slow subsidence area, so I would say there were some really interesting patterns in that and unusual patterns that were unexpected, but the overall average rate in my opinion was not too different from what people have said in years past.

Jacques: And it's within the range of the 2017 Coastal Master Plan considers.

Alex: Yeah, the master plan. You know, we're trying to, I think as scientists we're all trying to come up with a better map. That's within the range that people have talked with the master plan. It's a little slower in some places and in a little faster in others, but that's within the range of what we had thought for the … yeah, within the range.

Jacques: And let's dig into that a little bit because you were at Caernarvon today where we've taught there's been land building as a result of that freshwater input. You mentioned Wax Lake Delta as an example of hope for Louisiana because of the land building, but why is the land sinking more quickly in those areas?

Alex: So, freshly consolidated sediments tend to sink, tend to compact, right? So, the sediment around here, a lot of the Louisiana coast is kind of, in a way, it's mucky, it's sort of light and fluffy as far as like geological materials go, and they settled out over time. So freshly deposited sediments tend to sink a little bit more quickly than old consolidated sediments. Likewise when you have freshwater, when you put a lot of sediment you can load the area. Sediment is heavy and you can load the areas and cause areas to sink.

Jacques: But I guess that's why it's important to have that kind of replenishment.

Alex: Right, so okay. So part of the reason that diversions are a key part of the coastal master plan is that they continually add sediment to the marsh. That they're a relatively consistent supply of material and so as the land sinks and as water levels go up, you constantly need to add new sediment to the area and diversions do that without all of the, they do it basically in a way, once you've built a structure for almost for free because you're just constantly adding material, so it's a relatively efficient, both economically and environmentally, way to both build new land and maintain the land that's already out there.

Jacques: Great, and I want to talk a little bit more about that when we come back from the break. I know you did a tour with WWNO in New Orleans of potholes, the pothole bike tour.

Alex: Yes, we did. It was one of the most fun interviews and one of the most fun things I have done here in coastal Louisiana.

Simone: So we always ask a fun question, but Alex, what was your favorite pothole?

Jacques: Was it the one with the Christmas tree in it?

Simone: We'll talk a little bit more about that when we get back from the break, yes? Thank you BJ. All right.

Jacques: All right.

Simone: We'll talk to you soon. We'll talk to you when we get back.

Jacques: All right. We're back. You're listening to Delta Dispatches. We're discussing Louisiana's coast, it's people, wildlife and jobs and why restoring it matters. We're here with Dr. Alex Kolker and Dupree, very special guest.

Simone: Patty's favorite.

Alex: He's the coastal zydeco retriever.

Simone: We were talking potholes before the break.

Alex: Potholes are actually a part of subsidence, part of the subsiding picture here, so the ground, New Orleans is subsiding and some of these pothole features are part of the subsidence of the area, and actually parts of New Orleans are very rapidly subsiding and some of the places that have the worst potholes like Lakeview are, it's in part because they have the highest rates of subsidence.

Simone: Yeah, we were joking about the pothole bike tour, but I mean this is a way that people right here, the way that you just connected that, that potholes are caused by subsidence, but that's also some of the non-structural features that people have here in New Orleans, why they have slabs and elevated homes.

Alex: Right. Because New Orleans has always been built on the marsh and it's a naturally poorly drained environment and people here need to think about how do we live with water in the city, and to some extent, one mistake that we made in the past was that they ran the pumps very hard in years past, and when you dry out the marsh and the marshy soils that make this area, you can lead to subsidence.

Simone: So it upset the balance in a way.

Alex: It upset the balance in a way, and part of the sinking is because they were overly aggressive in pumping water out of the city of New Orleans.

Jacques: Yeah, and I know there's some attempts and kind of to look at how we can better live with water. There's discussion about the Gentilly water district.

Alex: Right. And a lot of that, the idea is to hold water in the soils for longer so that it can soak into the soil so the ground doesn't sink, so we don't get that sinking that's caused by drying out.

Simone: So to talk a little bit outside the city, you studied West Bay and Davis Pond diversions, so tell us a little bit about those diversions, and we talked about you were just at Caernarvon and people may pass them and don't even know what that is right there.

Alex: I know. I mean, a diversion, it's sort of an odd word, right?

Simone: Yeah, right. Right.

Alex: But it's basically, a diversion is an artificial small mouth of the river, right? It's basically a cut in the river that kind of mimics the mouth of the river and the areas where the flow spreads out and because the flow spreads out and slows down, a lot of mud settles out and this is originally how the coast was built and these are the kinds of features that people want to construct or encourage as part of coastal restoration, and in some ways I can understand why it's hard to, people don't know about them because you don't need to get up in the air or out on a boat. There not necessarily the most accessible places, so I can understand why they can be a little bit confusing for people.

Simone: Agreed. And I know, so they had a diversion expert panel that was put together to study some of these issues, and I remember talking to one of the scientists who came from out of state and he said "So basically you want control," and that's what a diversion is, right? It's that control.

Alex: It's almost like controlled chaos. I don't know if that's exactly the right word, but you want, in some ways you want control so that you can maximize the benefits and minimize the impacts, but you also don't want it over-controlled because you also want to let nature do what it's good at, and in part the reason that diversions are a really efficient way to build land is that we don't have to control every single part of them.

Jacques: And Alex, I know you were part of a team of scientists that comprised the sediment diversion expert operations working group, and one of your main studies was around when to open a diversion to maximize the amount of sediment.

Alex: Right, and the short story is that you often want to open a diversion to their max, let's say late winter, early spring when the river is rising, and that turns out to be the time when there's the most sediment in the river, there's the most mud in the river, and so you have the most chance of success, and at the same time, you're going to have the fewest problems because the oysters can deal with, I've been told they can deal for example with freshwater if it's relatively cold. The people that are concerned about shoaling in the Mississippi River and impacts to navigation, those problems are certainly less when the river is high, so often late winter, early spring turns out to be a good time when you can get the most benefit, but you also have the fewest adverse impacts.

Simone: Yeah, I think that was really one of the thoughts, I think, that when people hear diversion and we talk about controlled chaos, but I mean, we're not letting lose 75,000 CFS whenever we want. I mean, it's very controlled. It's very thought out, and the operations working group that you all went into a deep dive on that when might be best when can you get the same bang for a different buck.

Alex: Right, and because I can understand, 75,000 CFS is … it's a lot of water.

Simone: Yeah.

Alex: It would be, I mean, I grew up on the east coast, so that's about three times the size of the Hudson River.

Simone: Right.

Alex: That would be like one of the top 20 rivers in the country, right? So that's a big amount of water, and I can understand that if you were not careful about it, it could lead to problems, but I think that part of the idea of this working group was to look at how you can deal with it in a controlled and regulated way so that you maximize the benefits and minimize the impacts. And so really crank them up when you can get the most land building but scale them back when you might have the most potential adverse impact.

Simone: Yeah, so even projects like David Pond, I mean, they have an operational plan and control.

Alex: Right, and I was told every single water control structure in this country has an operational plan. The idea is that you pre-decide when you're going to open it and when you're going to close it and you've got certain thresholds.

Simone: Right.

Alex: And so I think that with this diversion, we're going to want to have the same kind of structure that when the flow gets to … when we have X, Y and Z conditions, it gets opened up and that would also give people the predictability because they would know when that diversion was going to be opened up, right? So we kind of all know when the river gets to X point they open up the Bonnet Carré Spillway. This would be something like that and people could pretty much see what's happening in the river, and the meteorological forecasting has gotten a lot better. We can predict the river stage pretty well almost a month in advance, and so you could look at those predictions and it would be like an almanac and you could start to make, if you were a fisherman and you were concerned about potential impacts, you could look at the weather and figure out when they were going to open it and plan around that.

Jacques: And Alex, kind of shifting gears a little bit, you mentioned that at LUMCON, you're K to gray, and having worked in this space for so long, do you see an uptick and interest among the scientific community or even among students in studying and looking for solutions on Louisiana's coast?

Alex: I have noticed that students are really interested in coastal issues. I've just noticed and even at the university classes that I teach, when I talk about sediment, some people are into it, some people are not, and when I talk about coastal issues, people really respond, and I think that people have really, people really take to coastal issues in part because it's this fascinating sort of mix of both the science and the human, and it's not just about getting the science right. It's not just about getting the people right. It's about doing both, and I think that that it's a challenging problem and I think it's a really engaging problem, too.

Simone: I agree. We were talking about Terrebonne had a coastal day and 700 people came to the event.

Alex: Which is great.

Simone: Yeah. It's amazing.

Alex: That that many people are that interested in the coast.

Simone: Right. And I think a lot of it has to do with people like you and some of the other folks that we've had on, Alicia Renfro and Dr. Reid, that have made it all so accessible for them to understand.

Alex: I would hope so. I would take the compliment, but I think it's also that people are really concerned about the area that they live in and that they're really engaged, and so maybe some of us that are loud mouths have had some role, but I think it's also just that people are really concerned about their area that they live in.

Simone: So we have to wrap it up and we always ask a fun question before we go. So you're stuck on a barrier island with only three things. What three things would you bring?

Alex: Fresh water and my dog.

Simone: And then whatever comes your way, you get an extra fishing pole.

Alex: Yeah.

Jacques: Well thank you so much Dr. Kolker and Dupree for being on.

Simone: Dupree's running for mayor.

Alex: He's running for mayor. He's got a Facebook page and everything. Dupree for Mayor. But thank you all and please come down to Cocodrie. Come down to LUMCON, and we'll show you around.

Jacques: And the website for LUMCON.


Simone: Great. Thank you so much.

Jacques: Thank you so much and this has been another wonderful episode. It's great to be reunited and I thank our guests. This has been Delta Dispatches and we will see you next week.

Simone: See you next week.

Jacques: Thank you all.