Subscribe to our free daily newsletters
. Earth Science News .




Subscribe to our free daily newsletters



WATER WORLD
Research sheds new light on forces that threaten sensitive coastlines
by Staff Writers
Bloomington IN (SPX) Apr 24, 2017


File image.

Wind-driven expansion of marsh ponds on the Mississippi River Delta is a significant factor in the loss of crucial land in the Delta region, according to research published by scientists at Indiana University and North Carolina State University. The study found that 17 percent of land loss in the area resulted from pond expansion, much of it caused by waves that eroded away the edges of the pond.

The findings add to scientists' understanding of the processes that shape the Delta and present new challenges for scientists and engineers seeking ways to protect sensitive coastlines.

"The Mississippi Delta is undergoing collapse as land disappears from the coast and marshes," said study co-author Douglas Edmonds, assistant professor and the Malcolm and Sylvia Boyce Chair in the Department of Earth and Atmospheric Sciences at IU Bloomington. "Yet we know surprisingly little about what processes are driving land loss."

River deltas are ecologically important and highly productive, and they are home to about 5 percent of the world's population. Under naturally occurring processes, coastal land is created in deltas when river sediment is deposited. But sea-level rise and human engineering of river channels have starved the Mississippi Delta of sediment, creating widespread land loss. Any hope of reversing the trend, Edmonds said, requires a clear understanding of the processes at work.

To conduct the study, the researchers analyzed satellite images taken from 1982 to 2016 across the Delta.

"In total, we looked at 10,000 images and classified approximately 1.29 billion pixels into land or water," said Samapriya Roy, a doctoral student at IU in geography and another co-author on the paper. "To do this we took advantage of the supercomputing resources at Indiana University."

Much of the pond expansion the researchers observed was in a southwesterly direction, driven by prevailing winds from the northeast. Expansion was significantly greater in ponds larger than 300 meters in diameter, where larger waves were more likely to erode the edges.

"Our analysis shows that ponds across the deltaic plain are moving and expanding in the same direction as the wind," said Alejandra Ortiz, the study's lead author and an assistant professor of civil, construction and environmental engineering at North Carolina State University. "That such evidence emerged over this expansive study area was surprising, because we thought sea-level rise would be the dominant control on pond expansion. We were also surprised by how important pond expansion is to total land loss on the Mississippi River Delta."

The study points to the importance of river-borne sediment. Because scientists thought sea-level rise and storm surges were dominant threats to coastlines, coastal protection has largely focused on building walls, embankments and other structures to combat rising seas and adding land to replace what's lost or left underwater. But the expansion of ponds would take place even if sea levels weren't rising.

"Most current restoration strategies call for diverting sediment to the coastline where rising sea level is a threat," Edmonds said. "Our work points out that sediment should also be diverted to marsh ponds to halt expansion."

On the Mississippi, dams and flood-control barriers have changed the flow of the river and reduced the amount of sediment deposited at the Delta to replace land that is lost to flooding and erosion. But it's also possible to build diversions that direct river sediment to where it is needed.

"Restoring these pathways of sediment movement is key to reversing the trend of land loss," Edmonds said. "Sediment is a valuable resource in the Mississippi Delta, but unfortunately it is in short supply."

Research paper

WATER WORLD
Degraded coral imperils coastal people: study
Paris (AFP) April 20, 2017
Coral reefs may be losing their ability to shield coastal communities from storms, sea surges and tsunamis, geologists said on Thursday. More than 200 million people around the world depend on coral reefs to protect coastal homes and beaches from the ravaging impact of high seas. But this vital buffer is at threat from reef degradation, according to a paper published by scientists at the ... read more

Related Links
Indiana University
Water News - Science, Technology and Politics


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

WATER WORLD
Japan disaster minister to resign over quake gaffe: reports

The Nepal quake survivors who can never go home

Rights group urges China to release N. Korean refugees

Ukraine, Belarus leaders mark Chernobyl anniversary

WATER WORLD
MIT engineers manipulate water using only light

NIST method sees through concrete to detect early-stage corrosion

Tweaking a molecule's structure can send it down a different path to crystallization

Lasers measure jet disintegration

WATER WORLD
Humans threaten 'fossil' groundwater: study

Research sheds new light on forces that threaten sensitive coastlines

In Mexico City, water a rare commodity

Croatian rivers face hydroelectric peril

WATER WORLD
More Antarctic protections urged on World Penguin Day

Reindeer at risk from Arctic hot spell

Methane seeps in the Canadian high Arctic

How polar bears find their prey

WATER WORLD
A novel form of iron for fortification of foods

New data unearths pesticide peril in beehives

Climatic effect of irrigation over the Yellow River basin

A better way to predict the environmental impacts of agricultural production

WATER WORLD
Atlantic storm season starts early, putting energy industry on notice

Nepal quake injured stalked by disability two years on

Report identifies grand challenges to better prepare for volcanic eruptions

At least 11 killed in Colombia floods: Red Cross

WATER WORLD
Top conservationist wounded in Kenya gun attack

US Defense Secretary Mattis visits strategic Djibouti

Morocco, US stage joint military exercise

Gambia's race to save its 'Roots' on Kunta Kinteh island

WATER WORLD
Indonesian hobbit evolved from African ancestor

Neuroscientists measure 'higher' state of consciousness

Putting social science modeling through its paces

Science says: Let a stranger pick your profile picture




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement