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/

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Soil Pollution

Today is World Soils Day, time to talk about soil pollution and wetlands! Soil pollution is often referred to as “invisible” because, although pollution can be detected through testing, it is much more difficult to see with the naked eye. Some of the biggest players in soil pollution today are improper waste management, agricultural runoff, and industrial processes. You may not think you are directly impacted by soil pollution, but you are.

Polluted soil in agricultural fields is arguably the most direct impact to humans because the pollutants are taken into the crop, whether it is a plant or animal, and make it into our food stream. [1] Pollutants in soils are also less hospitable to plant recruits, which is terrible news for coastal Louisiana. Our coastal wetlands provide us with many things that we rely on, and we cannot afford to lose our wetlands to preventable pollution. When soils do not incorporate healthy plant roots, they are much more susceptible to erosion. When moving sediments around, CWPPRA wants to make sure that plants can re-establish effectively, so they want healthy soils. [2]

Areas with unsustainable levels of pollution are spreading, and non-point source pollution, which includes road and agricultural runoff, is very hard to track and very hard to remedy. Pollutants are not easily scrubbed from soils on a mass scale and so they follow the flow of water. Runoff travels through watersheds just like clean water and makes its way into our coastal wetlands with damaging consequences. Coastal wetlands are resilient ecosystems, but they have limits. We cannot overburden them with harmful, carefree attitudes towards pollution. Our coast deserves to be protected. Our coast deserves to be respected.

[1] https://www.epa.gov/sites/production/files/documents/bioaccumulationbiomagnificationeffects.pdf

[2] https://www.lacoast.gov/crms/crms_public_data/publications/CRMS_FactSheet_Web.pdf

Featured image from https://soilsmatter.wordpress.com/2017/12/15/are-wetlands-really-the-earths-kidneys/

Little Vermilion Bay Sediment Trapping (TV-12)

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High winds and waves prevent GIWW sediments transported down the Freshwater and Schooner bayous from settling and forming the basis of vegetated marsh. This same wind and wave energy also increases shoreline erosion rates.

This project involved the construction of a series of vegetated terraces to diminish waves in Little Vermilion Bay, helping to increase sediment deposition and reduce the rate of shoreline erosion. A pattern of channels was dredged 100-feet wide and 6-feet deep to beneficially distribute sediment from the GIWW through the Freshwater and Schooner bayous. Dredged sediments were used to construct 23 earthen terraces with a combined length of 23,300 feet. After settling, the average height of the terraces was 3.5 feet above mean sea level.

The bases of the terraces were planted with 20,450 containers of smooth cordgrass (Spartina alterniflora).

The design allows commercial and recreational fisherman to access the project area, and it stimulates fishery production by creating new habitat and increasing shoreline length.

In 1998 alone (prior to the project’s completion) 40 acres of wetland habitat were created.

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This project is located in the northwestern corner of Little Vermilion Bay at its intersection with the Gulf Intracoastal Waterway (GIWW) in Vermilion Parish, Louisiana. The project area encompasses 964 acres.

Monitoring is underway and preliminary observations show that the terraces are growing in width, and bay depth between terraces is decreasing indicating marsh expansion in the project area.

This project is on Priority Project List 5.

The Federal Sponsor is NOAA NMFS

The Local Sponsor is CPRA

Louisiana’s Live Oak Cheniers

With coastal needs continuing to grow, we can learn from nature’s history for ways to strengthen our coastlines. While we often think about how barrier islands protect the coast from storms, coastal cheniers and forests across Louisiana are also essential in providing that protection. These coastal forests are often found on shell ridges known as cheniers.

French for “place of oaks”, cheniers act as storm barriers, prevent saltwater intrusion, and provide wildlife habitat for migratory birds and butterflies [1,3]. Cheniers along  Louisiana’s coast extend from Cameron Parish in the west to Iberia Parish” [1]. Due to their higher relief, or height above sea level, a large majority of these areas were cleared for human development uses such as highways, agriculture, and oil and gas [2]. Louisiana originally hosted 100,000 to 500,000 acres of chenier, but today only 2,000 to 10,000 acres remain [1].

While these numbers can be discouraging, local and state efforts are in place to conserve live-oak (Quercus virginiana) cheniers and coastal forests.

Louisiana is fortunate to have programs and organizations like this to conserve the coast and its natural abundance. These practices along with landowner, volunteer and citizen engagement are essential to coastal restoration. You may visit CWPPRA’s website lacoast.gov to learn how you can help Louisiana’s coastal wetlands!

Do your part to conserve our environment and help Louisiana’s coast!

Source:
[1] Louisiana Comprehensive Wildlife Conservation Strategy. Date Accessed October 30, 2018. Available:http://www.wlf.louisiana.gov/sites/default/files/pdf/document/32867-coastal-live-oak-hackberry-forest/coastal_live_oak-hackberry_forest.pdf
[2] Army Corps of Engineers. Southwest Coastal Louisiana Final Integrated Draft and Feasibility Report and Environmental Impact Statement. Date Accessed October 30, 2018. Available:http://www.mvn.usace.army.mil/Portals/56/docs/PD/Projects/SWCoastal/11%20Appendix%20A%20Env%20Report.pdf
[3] Baton Rouge Audubon Society. Accessed on 10/31/2018. Available:http://www.braudubon.org/peveto-woods-sanctuary.php

Ocean Commotion 2018

The 21st annual Ocean Commotion event was held at LSU on October 25, 2018. Sponsored by the Louisiana Sea Grant, Ocean Commotion is an opportunity to learn about coastal and oceanic issues. Held at the LSU Pete Maravich Assembly Center, 65 exhibitors provided hands-on learning about Louisiana’s coastal environment, sustainability practices, our beloved oceans, and the organisms that live here. More than 1,800 students, teachers, and chaperones from area schools had the opportunity to look at zooplankton with the LSU Department of Oceanography, build a delta with LSU Sea Grant, and come face to face with animals from Bluebonnet Swamp.

CWPPRA Outreach staff were set up with our Mysterious Wetland Wonders. Students read clues and then reached inside boxes (no peeking!) to identify plant and animal relics. From invasive apple snail shells to magnolia seed pods to a turtle carapace, each item can be found in Louisiana wetlands. Our wetlands are home to a diverse array of plants and wildlife and provide us with recreation, economic benefits, cleaner water, and other ecosystem services. Protecting these wetlands helps protect all of the groups that depend on them for food, shelter, and fun.

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CWPPRA Outreach staff were set up with our Mysterious Wetland Wonders. Students read clues and then reached inside boxes (no peeking!) to identify plant and animal relics. From invasive apple snail shells to magnolia seed pods to a turtle carapace, each item can be found in Louisiana wetlands. Our wetlands are home to a diverse array of plants and wildlife and provide us with recreation, economic benefits, cleaner water, and other ecosystem services. Protecting these wetlands helps protect all of the groups that depend on them for food, shelter, and fun.

Soil Cores

What can we learn from soil cores?

Soils and sediment can tell us a lot about the health of a wetland, including nutrient concentrations, average productivity, and flooding patterns. There’s a rich history in every soil sample that scientists can piece together if they know what to look for.

Soil cores are a method of collecting soils that allow the observer to get a vertical profile within a layer of sediment or soil. [1] Depending on the desired characteristic, cores can be a foot of material from the surface or they can be over 6 feet tall starting 20 feet below the surface. Each study using a core sample can tell a diverse story. For example, cores in coastal wetlands can be used at CRMS sites to measure accretion on top of marker horizons in an RSET-MH apparatus , in swamps to gauge the oxidation potential of soils, or in marsh to quantify the living root mass that provides structural integrity to platforms. Sediment types, decomposition, and bulk density can also be measured.

Knowing the quality of soils that you’re working with is important in planning for success in the restoration field. Poor soil quality will have lower success in repopulating native flora, as we discussed in our Wetland Wednesday post here. Soil cores lead us to a better understanding of processes that we may not be able to see and to predict the future of ecosystems. Soil testing is a crucial part of conservation and will be a vital tool in the fight to protect our coast.

 

Featured image from http://uwmyvatn.blogspot.com/2012/07/the-grass-is-always-greenerin-midge.html

[1] https://kb.osu.edu/bitstream/handle/1811/513/1/(98)%202.11%20Soils.pdf

Raccoon Island Shoreline Protection/ Marsh Creation (TE-48)

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The Isles Dernieres barrier island chain is experiencing some of the highest erosion rates of any coastal region in the world. Raccoon Island is experiencing shoreline retreat both gulfward and bayward, threatening one of the most productive wading bird nesting areas and shorebird habitats along the gulf coast.

An existing demonstration project on the eastern end of the island, Raccoon Island Breakwaters Demonstration project (TE-29), has proven that segmented breakwaters can significantly reduce, and perhaps even reverse, shoreline erosion rates. The primary goal of this project is to protect the Raccoon Island rookery and seabird colonies from the encroaching shoreline by: 1) reducing the rate of shoreline erosion along the western, gulfward side and 2) extending the longevity of northern backbay areas by creating 60 acres of intertidal wetlands that will serve as bird habitat. This project has been separated into two construction phases, Phase A and Phase B. Phase A includes the construction of eight additional segmented breakwaters gulfward of the island and immediately west of the existing breakwaters demonstration project and an eastern groin that will connect existing Breakwater No. 0 to the island. Phase B involves the construction of a retention dike along the northern shore to create a back bay enclosure that will be filled with sediments dredged from the bay and/or gulf, followed by vegetative plantings.

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The project is located in the Terrebonne Basin on the western-most island of the Isles Dernieres barrier island chain in Terrebonne Parish, Louisiana.

This project was selected for engineering and design funding at the January 2002 Breaux Act Task Force meeting. Construction funding for Phase A was approved in October 2004. Request for Phase B construction funding is anticipated to occur in January 2008.

This project is on Priority Project List 11.

The Sponsors include:

Federal Sponsor: NRCS

Local Sponsor: CPRA