Land Loss and Human Impacts

Louisiana’s shrinking coastal zone is due to both natural causes such as rising sea levels and wave erosion, but human activity intensifies these evolutionary processes. Some of the most impactful land loss processes further increased by human activity include salt water intrusion, proliferation of invasive species, and subsidence.

Hurricanes and other storm events push salt water inland, increasing the salinity of wetlands to levels that damage local flora adapted to lower salinities, causing those plants to die, which in turn decreases their potential to reduce storm surge around human settlements. Dredged canals for oil and gas exploration provide easy pathways for salt water to move inland since these canals are often straight. [1] Healthy marshes decrease the distance that storm surges can infiltrate, so any man-made development that diminishes intermediate or salt marshes indirectly affects freshwater wetlands as well.

Invasive species are plants, animals, or other biota that are from other regions of the world that cause harm to our local native environment. One such invasive species with extensive ramifications for our coastal wetlands is the Coypu, or “nutria rat.” This large rodent devastates stands of native graminoids such as cordgrasses (Spartina spp) and bulrushes (Schoenoplectus spp). Coypu specifically target the base of stems and roots, digging for them in soft sediment platforms. [2] Lower root concentration in soils and active disturbance make for weakened substrates that are more susceptible to being washed away. Other invasive species have similar outcomes, but not necessarily by the same method. We have several invasive animals and plants in Louisiana, each introduced by humans either on purpose or accidentally, and each one has a destructive presence along our coast. CWPPRA actively works to counter the destruction of invasive species through research, engineering and reward-based mitigation, such as the Coastwide Nutria Control Program. [3]

Louisiana was built by the Mississippi River over the past several thousand years, depositing layer after layer of soft, uncompacted sediment. Naturally, that sediment will compact, causing the surface to sink. Developing human settlements might speed up this process due to increased weight. Some cities are sinking as fast as 12 millimeters per year. Combined with rising sea levels, these areas are getting 15 millimeters (.6 inches) closer to sea level each year. [4] Combining the natural subsidence rates with unnatural marsh degradation, flooding will continue to worsen in our towns and cities. The Coastwide Reference Monitoring System (CRMS) tracks subsidence as well as several other ecological conditions and CWPPRA project performance over 391 sites along the Louisiana Gulf Coast. [5] Human activity is an integral component of Louisiana’s coastal zone, and CWPPRA works with biologists, engineers, local governments, volunteers, and residents to study those adverse impacts and devise innovative methods to address and deter them.

 

Sources:

[1] http://web.mit.edu/12.000/www/m2010/finalwebsite/background/wetlands/wetlands-degradation.html

[2] http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Myocastor_coypus.htm

[3] https://www.nutria.com/site9.php

[4] https://www.nola.com/news/environment/article_fc2fc043-f0a3-55a5-b1a5-ce96dc712c3e.html

[5] https://www.lacoast.gov/crms/Home.aspx#

 

Featured Image from JennyCuervo [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)%5D

Watersheds and International Day of Action for Rivers

Water flows from the higher elevations of the northern United States to our low-lying wetlands. Surface elevation, on average, decreases from the northern border with Canada all the way to the mouth of the Mississippi River. What that means is that most of the water that falls between the Rocky Mountains and the Great Smoky Mountains drains into the Mississippi and eventually in the coastal waters of Louisiana. We call this area the Mississippi/Atchafalaya River Basin (MARB) or the Mississippi River Watershed. [1] A watershed, by definition, is an area that drains to a river or lake. The Mississippi River Watershed encompasses nearly 41 percent of the United States.

Streams and ponds in the higher elevations of our watershed are fed by precipitation (rain, snow, hail, etc.) or springs. Water always follows the path of least resistance, which is downhill. Even on gradual slopes, water will seek out lower elevations. Flow rate is dependent on the angle of the slope, also called the elevation gradient. This explains why rivers in more mountainous regions flows faster than in our very flat land. Of course, some water will evaporate, some water will seep into the ground, and the rest will continue downstream until it gets to the ocean. While there are some exceptions to that rule, such as the Great Salt Lake in Utah and other Endorheic basins (no outlets besides evaporation), most water that falls on land will follow the water cycle that we all learned in grade school.

In Louisiana, the MARB outlets are the mouths of the Atchafalaya and Mississippi rivers and their distributaries. Because the state receives this water runoff through our bayous and marshes, so too does it collect  the trash and other pollution from the watershed. This pollution includes not only typical litter and non-point-source runoff, but also agricultural runoff that carries an abundance of nutrients. Select groups across the state are employing litter collection traps in bayous and streams to prevent trash from ending up in our coastal waters. More about these issues can be found in our articles about hypoxia stress and soil pollution.

The International Day of Action for Rivers will be celebrating healthy watersheds worldwide tomorrow, March 14. [2] We encourage our readers to do a little cleaning in their local waterways year-round but especially tomorrow. There are several groups around the state who organize clean-ups in our local waterways for any who are interested. Some of these groups can be found in our sources. As the third largest watershed in the world, the MARB supports numerous ecosystems and human settlements, and it is crucial that we keep it healthy for all its constituents. Each day, our coastal wetlands protect our cities and ports, so we at CWPPRA strive to return the favor and #ProtectOurCoast.

 

[1] https://www.epa.gov/ms-htf/mississippiatchafalaya-river-basin-marb

[2] https://www.internationalrivers.org/dayofactionforrivers

Featured image from http://www.bayouvermilionpreservation.org/photos.html

 

Action groups:

 

City of Lafayette: http://www.lafayettela.gov/EQ/Pages/Environmental-Outreach.aspx

Bayou Vermilion District: http://www.bayouvermiliondistrict.org/

Sierra Club: https://www.sierraclub.org/louisiana/what-do-you-want-do

BREC: http://www.brec.org/index.cfm/page/GroupVolunteerOpportunities

BTNEP: https://volunteer.btnep.org/

Competitive Dominance Pt. II

Last week, Wetland Wednesday focused on dominant species in wetlands and conditions that contribute to competition. Last week we talked a lot about plants, but animals can be dominant in wetlands as well, for example the American Alligator (Alligator mississippiensis).

Alligators are one of the most recognizable predator species of swamp and marsh habitats, but they haven’t always been as numerous as they are now. Alligators were endangered as recently as 1987 due to human impacts, especially hunting. [1] Since their conservation proved so effective, they are no longer on the endangered species list, but instead are now “of least concern”. It is impressive to see such a strong recovery for an endangered species, and their recovery was successful for many reasons, including their lack of strong competitors. Very few animals compare in size or bite strength. As apex predators, they have essentially free reign over other species when they reach maturity, although there is some competition between individual alligators. Productivity in swamps and marshes is extremely high compared to other habitats, so there is plenty of food to go around, but they still compete with birds of prey and other large aquatic animals like alligator gar and alligator snapping turtles (those names probably aren’t coincidental…).

As we mentioned last week, dominant species are not always native. Invasive species like nutria, or coypu, often out-compete native muskrats for similar food sources and homes. Since nutria are larger than muskrats, fewer species can prey on them. [2] Invasive species like nutria can disrupt communities of native species to the point of local extinction in some cases, especially in island ecosystems. [3] Not all introduced species are invasive; some do not significantly impact their new homes. Invasive species are detrimental by definition. Nutria were originally introduced by humans, which means their dominance over native muskrats is a byproduct of human activity. Similarly, zebra mussels and apple snails were introduced by humans and out-compete native species in coastal Louisiana.

Many species face the threat of population decline due to human activity, whether directly or indirectly. In a way, nearly all species on the planet are in competition with humans for food, territory, etc. or compete against one another to survive amid human impacts like climate change. Humans have done a great job altering landscapes to become livable for us, but those landscapes aren’t always good for native species. This kind of disruption has consequences to our own safety, however. Degradation of coastal marshes in Louisiana has been a consequence of human activity, and the risk of lowered wetland protection from storms poses a threat to our settlements. Since we have invested so much in where we live, it is in our best interest to reverse some of the damage we have done to those areas. CWPPRA is dedicated to coastal restoration because it is a responsibility we owe to both the environments we have disrupted and our communities that have come to depend on these environments.

[1] http://www.endangered.org/animal/american-alligator/

[2] https://www.aphis.usda.gov/publications/wildlife_damage/content/printable_version/fs_nutria10.pdf

[3] http://www.pacificinvasivesinitiative.org/site/pii/files/resources/publications/other/turning_the_tide.pdf

Featured image from http://www.louisianaherps.com/american-alligator-alligato.html

Environmental Education

This week is a big one for us in habitat conservation and restoration.  This past Saturday, we celebrated World Wetlands Day and took some time to appreciate the variety and importance of wetlands around us. In case you didn’t see it, we posted on Monday about our Friday spent with students in Houma, LA. This week is also the official start of National Green Week, a set of programs developed by the Green Education Foundation (GEF) in the United States!

Across the country, schools will be offering GEF programs between now and the end of April to foster greater environmental consciousness. Programs that are offered can be found on their website, listed in our “sources” section. Programs consist of 5 days of lessons and associated activities, and they explore multiple topics within themes such as green energy, waste reduction, and sustainable water. Our hope is that schools in our state implement similar lessons. Thanks to programs like National Green Week, we have more citizens who are conscious of human impacts on ecosystems than ever before. In Louisiana, programs like CWPPRA, BTNEP, and CRCL focus on telling the story of coastal land loss and all the potential consequences of letting it happen. Environmental awareness of topics like clean water, energy efficiency, and waste reduction has major benefits to the health of our coastal zone. For more information, feel free to check out our posts about measuring water quality and soil pollution.

The mission of environmental educational programs is to start conversations and lay a solid foundation of knowledge that students can build on. Being introduced to pressing environmental issues at early ages nurtures better stewardship and more productive attitudes when it comes to the challenges of coastal erosion, deforestation, pollution, and other issues. In Louisiana, legislators are already beginning to realize the severity of our disappearing coast and are making changes accordingly. For this, we are extremely fortunate. We are proud to work alongside CPRA and our other partners towards our mutual goal of a resilient Louisiana coastline, and we look forward to the younger generations adopting this mission.

 

Sources:

https://www.worldwetlandsday.org/

http://www.greeneducationfoundation.org/greenweek.html

Featured Image from https://en.wikipedia.org/wiki/Cypress_Lake_(Lafayette,_Louisiana)

Looking Back

Former President George H.W. Bush signed Public Law 101-646, Title III CWPPRA into law in 1990 to combat the national issue of coastal land loss. Over 25 years after he left office and a week after the late President’s day of mourning, this legislation is still providing protection to billions of dollars’ worth of industry, major human settlements, and beautiful ecosystems.

At 28 years of projects and counting, CWPPRA is among the longest-standing federally-funded restoration ventures in the country, as well as one of the most successful. To date, 210 projects have been authorized across Louisiana’s coastal zone to restore 100,000+ acres of wetlands. Each year of operation, CWPPRA has approved funding on multiple projects scattered across our coast. The locations of our projects can be found at https://lacoast.gov/new/About/Basins.aspx.

CWPPRA projects are proposed by anyone and developed in conjunction with one of our 5 federal managing agencies and Louisiana’s Coastal Protection and Restoration Authority. The process of project selection is always a rigorous competition between candidate projects across Louisiana’s coast. Each proposal presents estimated ecological benefits, cost estimates, and a detailed plan for the desired project. At the beginning of each calendar year, Regional Planning Team meetings are held across the coast to hear proposals. The proposed projects are compiled into an annual Project Priority List (PPL). Upcoming proposal meetings can be found Jan 29-31, 2019 on our calendar at https://lacoast.gov/calendar/. Over the next year the CWPPRA Technical Committee and Task Force narrow the list of candidate projects. In December, the Technical Committee recommends their top 4 projects to the Task Force. The Task Force finally votes in January on the 4 projects they will fund for Phase I Engineering and Design. This annual cycle will complete its 28th round in late January 2019.

CWPPRA is excited about wrapping up PPL 28 next month and starting on PPL 29! Be on the lookout for announcements about projects chosen for funding at the January 24th Task Force meeting. We look forward to continuing our efforts to #ProtectOurCoast!

 

Featured image from https://projects.propublica.org/louisiana/

Cameron Prairie National Wildlife Refuge Shoreline Protection (ME-09)

wordpress fact sheet banner ME-09-01

The management levee between the GIWW and the
Cameron Prairie National Wildlife Refuge was in danger
of breaching as a result of erosion from boat traffic in the
GIWW. If breaching had occurred, wave energy from the
GIWW and salt water would have entered the organic,
freshwater wetlands.

A 13,200-foot rock breakwater was constructed 50 feet
from the northern bank of the GIWW to prevent waves
caused by boat traffic from overtopping and eroding the
remaining spoil bank.
The project’s effectiveness is being evaluated by shoreline
movement surveys and by comparing pre-construction and
post-construction aerial photographs for changes in marsh
loss rates.

map.jpg

This project is located in Cameron Parish, Louisiana, on
the north shore of the Gulf Intracoastal Waterway
(GIWW), approximately 7 miles southeast of Sweet Lake
and to the east of Louisiana Highway 27 at its intersection
with the GIWW. It encompasses 640 acres of fresh marsh
and open water.

During 1993-97, while the project area had a 4.9% increase in
water coverage due to management for waterfowl, the
reference area remained unchanged.

The results of shoreline monitoring indicate that the project
has protected 13,200 feet of shoreline, along with 247 acres of
marsh north of the dike. This protection is expected to accrue
throughout the life of the project for a net restoration of at
least 23 acres. Monitoring has shown that the GIWW’s
northern shoreline advanced 9.8 feet per year in the project
area while retreating at a rate of 3.0 feet per year in the
reference area, indicating that low sediment availability does
not prohibit wetland creation behind rock dikes on navigation
channels.

To date, the project has exhibited success. It is expected that
the project area will continue to accrete new wetland area
between the spoil bank and the rock dike, further
safeguarding the adjacent wetland area from encroachment by
the GIWW.

This project is on Priority Project List 1.

 

The Federal Sponsor is USFWS

The Local Sponsor is CPRA

Living Shorelines

According to NOAA, one of our managing agencies, a living shoreline is “A protected and stabilized shoreline that is made of natural materials such as plants, sand, or rock.” [1] In some situations, living shorelines are a better option than hardened shoreline protection because they have more movement of natural sediment, the ability to grow, and the obvious aesthetic value of a natural area.

‘Living shorelines’ can refer to multiple restoration techniques and coastal environments; for CWPPRA, a living shoreline can mean vegetative planting on a marsh creation cell or using a shoreline protection barrier that promotes oyster reef growth. Living restored shorelines help maintain the integrity of ecosystems, but they also provide benefits to recreation and potentially to commerce. One big push in restoration over the past few years has been artificial oyster reefs which provide wave attenuation, natural water filtration, and a harvestable population of oysters for the seafood industry. [2]

Illustration, Courtesy of NOAA [1]
Vegetated marsh provides similar benefits to artificial oyster reefs and is a tried-and-true restoration strategy. Many marsh creation projects will naturally revegetate thanks to seed banks in borrow sites but some need management to limit invasive species. In more vulnerable sites, CWPPRA actively plants native species like smooth cordgrass and California bulrush to give them an advantage against invasive populations.

CWPPRA understands that successful restoration projects, including shoreline protection, help keep ecosystems intact and productive. A changing coast means we need changing solutions, and we will strive to find better alternatives to maintain the natural environment.

[1] https://oceanservice.noaa.gov/facts/living-shoreline.html

[2] https://www.smithsonianmag.com/innovation/storms-get-bigger-oyster-reefs-can-help-protect-shorelines-180967774/

Featured image from https://oceanbites.org/oyster_reef_restoration/