AUSTIN (KXAN) — River deltas along the Mississippi River have seen some massive changes in recent years. Not only are many parts of the delta losing land, but there are also areas that are growing — and climate change and human action in the area are to blame for some of these changes.
Meteorologist Sean Kelly spoke with researchers at the Jet Propulsion Laboratory about the satellite and some of the breakthroughs they’ve made. You can read a full transcript of that interview below or watch an edited video above.
SEAN KELLY, KXAN NEWS: What is the Delta-X? And what are some of the mission goals?
CATHLEEN JONES, SENIOR RESEARCH SCIENTIST, JET PROPULSION LABORATORY: Yeah, so Delta-X is one of NASA’s Earth venture suborbital missions. The goal of Delta-X is to study how land is lost or gained in low-lying deltas around the world, and in particular, in the Mississippi River Delta. That’s where we’re doing our study.
KELLY: And what are some of the findings of your study so far?
JONES: Well, it’s kind of interesting. The X in Delta-X is for exchange: It’s about the exchange of sediment and water between rivers and wetlands and about how that exchange mediates whether land builds or land is lost.
So there are a couple of factors that go into this. One is whether you have sediment coming in from up river, just whether you have any new soil to deposit in this area. And whether the water brings that sediment into the wetlands instead of flushing it down the river and out to sea.
But an interesting component is vegetation, and how vegetation influences whether land builds or is lost. Vegetation does two things. One is that when water flows through vegetation, it slows down, and so the sediment is more likely to drop out. So you get more sediment dropping out.
The other thing is that plants build soil directly through their roots. And whenever they die, they drop on the ground and they contribute to organic soil build up and primarily all the sediments coming down from rivers.
KELLY: Is there anything that enhances sediment? Is it, is it rainfalls? Does drought have an impact? Are there any or do you notice any changes with, I guess, weather [and] climate impacting the amount of sediment coming downstream? Or is there any impact by agriculture?
JONES: Yeah, I know that if you dam up river, like you build a dam up river, then you collect sediment behind the dam, and it doesn’t come down river. That would be one thing that could influence it.
For Delta-X, we just measure the sediment that’s coming in, and then we track how the sediment moves through the wetlands and whether it accretes on the soil or whether it’s washed out. And then we relate that to vegetation. You know, how much vegetation there is? The elevation? How much water goes over the sides of the river into the wetlands? How much of it moves through these tiny channels that distribute water throughout the wetlands?
KELLY: Are we losing more wetlands than then gaining?
JONES: Right now we are. Yes. And Delta-X is actually kind of interesting, because we’re studying an area of the Mississippi River Delta, where you have one basin that’s gaining land quite nicely. And right next to it, you have a basin that’s losing land.
And then these are the same climate, you know, they’re subject to the same forces from the Gulf climate wise, same weather, essentially. But one is gaining land and one is losing land.
So it’s like a perfect, you know, controlled experiment for determining why that’s happening. And so, we measure the channel network, how water flows differently through these two areas, how sediment — the input of sediment — is different in those two areas, how the vegetation is different in order to try to understand what the controlling factors on what makes an area land and what makes another area.
KELLY: Do you find that hurricanes play a role in erosion and impacting wetlands?
JONES: Hurricanes do two things, although we’re not really studying that. I should say that they do two things: They bring in a lot of sediment, but they also have a lot of force and and can affect the vegetation.
Most of the vegetation in those areas are developed under conditions where they’ve been, they’ve been exposed to hurricanes. They’re tolerant to hurricanes, though. So it’s natural, it’s a natural process that they’ve lived with.
KELLY: So with with the research and findings, what would be some overall goals for you know, the years ahead to find ways to be able to rebuild lost land?
JONES: Yes, of course, yeah. That’s our goal…if you understand the processes that cause land to be lost, and you understand the processes that permit you to retain land or even build land, then you can, you could, in principle, be able to design projects that help you to build land instead of losing it. So that’s our big goal, is to understand what is causing land loss?
