Turning the tide

It was an environmental disaster on a huge scale affecting a formidable ecosystem. In June 1979, the Ixtoc I exploratory oil well blew out in Bahía de Campeche, 600 miles south of Texas in the Gulf of Mexico. The well was not capped until March 1980, by which time more than 3.3 million barrels of oil had spilled into the ocean. Devastatingly, that oil started heading towards the Texas coastline and the biologically rich Aransas National Wildlife Refuge.

To help protect the region’s delicate wetlands and intricate bay systems, the State of Texas decided to close the ephemeral pass at Cedar Bayou, cutting off Mesquite Bay from the Gulf of Mexico and protecting its waters from the approaching oil. Once the beach clean-up operation had been completed, however, the pass remained closed – Cedar Bayou was cut off from the fruitful waters of the gulf.

Where the bayou had been a lively breeding ground for fisheries, blue crab – the primary diet of the endangered whooping crane – and endangered sea turtles, the lack of a flow of water from the gulf meant that its once thriving marine life began to deteriorate.

The closure hit hard, keeping the eggs and larvae of fish, shrimp and crabs from entering the bayou. Its ecosystem crashed, and with it the area’s fishing and tourism industries.

Local groups made several attempts to open the pass, but all ultimately failed, and it was not until 2004 that the first steps were made towards opening the pass and restoring Cedar Bayou to its former glory.

Look back to move forwards

The recovery process began when the state government connected the action group of local commercial and recreational fishermen, Save Cedar Bayou Inc, with engineering consultancy Mott MacDonald.

The two organisations started working together to help secure funding for reopening the channel. This effort was continued by Aransas County and led by County Judge Burt Mills, who recognised the importance of the pass to the environmental ecosystem and local community. His efforts secured construction permits and funding for construction to go ahead.

Hugo Bermudez was appointed as project manager by Mott MacDonald. The team started a coastal engineering and hydraulic analysis to assess what had caused the closing and opening of the pass and how this impacted on the ecosystem.

“We found that, back in the 1950s, there had been a big study of fisheries passing from the Gulf of Mexico into the bay system through Cedar Bayou that described how abundant and lively the system was,” Bermudez says. “We also looked at historical aerial photography back to the 1930s and rectified some of that photography to see different historical openings and closings of the channels. We found some human interventions as early as the 1930s trying to open the pass, and it remained open for quite a while after that, [until the oil spill].”

This analysis helped Bermudez identify how previous dredging attempts failed due to the location where the excavated material was disposed of, and its subsequent impact on water flow, allowing Mott MacDonald to establish a plan for permanently opening the pass.

Bermudez and his team filed for a permit for dredging that would allow the excavated material to be discarded downstream, where it would not limit the flow of water, but regulatory issues made it much more difficult than envisaged to push ahead with the plans for regeneration.

“The agencies received a lot of complaints [after previous dredging attempts] because the material was not disposed of in the proper way and had an impact on the natural resources of the area,” Bermudez says. “So they were very sceptical about anything else being done in that area to help resolve the issue.

“They felt that the two engineering projects previously carried out were enough and they weren’t going to allow a mistake to be made again.”

Going with the flow

The regulators required the regeneration team to perform a study into how their plans would affect the area. After several years of surveys and changes to the plan to reduce the environmental impact of the dredging, a permit was granted in 2013.

This permit required a further phase of monitoring the fisheries, sea grasses and other endangered species. In 2014, the 10-year project finally got under way. It involved removing 540,000 cubic yards of sand using a combination of hydraulic dredging, excavators and off-road trucks, restoring a large volume of flow for the first time in 35 years.

As would be expected in such a project, environmental issues continued to remain at the fore throughout the work, and construction stuck to a tight timescale to avoid impacting on the migration patterns of birds in the region.

“We had to do construction in a very short period of time [to avoid migration seasons],” Bermudez says. “To keep the project under budget, the equipment came through the pass instead of going through the Gulf of Mexico, so we didn’t need ocean vessels. To do that, we had to do surveys of the area and execute the project within a very restricted time frame, while also measuring sea grasses and monitoring migratory birds in the area.

“Mother nature was definitely behind us – we had a lot of rain right after the pass opened, and we had been in a drought up until that point,” he adds. “It is a difficult process to model, but we did know that one of the driving factors for keeping the bay open was rain.”

Now, two years later, the pass is wide open again.

Spectacular comeback

In 2013, before the reopening of the pass, a scientific study caught just 99 fish and 905 crustaceans. Towards the end of 2014, after the pass had been restored, the same study caught 715 fish and 6,963 crustaceans. That’s a greater than sevenfold increase in all sea-life levels, and blue crab numbers grew from as few as five to more than 175 in little over a year.

Mark Ray, board chairman of the Coastal Conservation Association in Texas, called the reopening “a dream come true – a $9m gift to the Texas coast”. He added that, “More fish, more crabs and more birds mean more birders, more fishermen, more hunters and more visits by folks who love the coast.”

With fisheries returned to normal levels, Cedar Bayou is once again harbouring the world’s largest flock of endangered whooping cranes, with people travelling from afar to enjoy the bayou’s spectacular comeback – bringing plenty of new trade for local businesses, and plenty for the local fishermen to catch.

Matt Scott is a business and data journalist.