In 2014, Texas dumped 126,000 cubic yards of mud dug from a ship channel onto a shrinking island; the unusual move rebuilt about 5 acres for nesting birds

Somewhere in Texas there was a beach that kept shrinking. Each storm took a little more of the shoreline the birds needed to raise their chicks. That was the problem on Sundown Island. According to a December 2014 news release from the U.S. Army Corps of Engineers Galveston District, the solution came from an unlikely spot: mud dug from a nearby ship channel.

An island under constant erosion

Sundown Island is an Audubon Society sanctuary for waterbirds that nest in colonies. The island was under constant attack from strong currents, wind, ship wakes, and storms, Corps operations manager George Dabney said in the release. That led to erosion of the shoreline and the loss of more than 20 percent of the island's 60 acres, or more than 12 acres.


Why a ship channel was on the table

The Matagorda Ship Channel was designed in the 1960s to allow deep-draft vessels to travel between Matagorda and Lavaca bays and the Gulf of Mexico, the release said. It is part of the Port of Port Lavaca-Point Comfort. The Corps reports that the channel carries about 11.6 million tons of commerce a year. Ships need the channel kept clear, and maintenance dredging is required every year to keep it available, according to Dabney.

Where the mud went

A $5.77 million dredging contract in 2014 removed about 1.2 million cubic yards of material from Matagorda Peninsula to Point Comfort, per the release. Some of the work was funded by the Calhoun Port Authority with non-federal funds for dredging port berthing areas. Of that work, about 126,000 cubic yards fell on Sundown Island. He called that a unique benefit of the contract. This came through cooperation with the Audubon Society and state and federal resource agencies.

What the five acres added

Adding that sediment to the beach added approximately five acres to the island, Dabney said. It mitigated erosion for years and created new habitat for ground-nesting species. However, it’s worth noting that five acres is less than the 12-plus acres the island lost. It didn't fix everything, but it gave the birds a little more space.

What happened next

The work continued. The Corps awarded three contract options totaling $4.3 million to Orion Marine Construction Inc. to dredge additional reaches of the channel in Matagorda and Calhoun counties. The release stated the contractor was required to remove an estimated 1,985,000 cubic yards, with completion then expected in early 2015. All that material was to be placed in unconfined open-water areas. That made the Sundown Island placement unusual. The Galveston District was organized in 1880 and was the first engineer district in Texas. It maintains more than 1,000 miles of channel.

Why the islands matter

This isn’t just Sundown Island’s story. Texas colonial waterbirds rely heavily on dredge spoil islands for nesting, a report by the Texas General Land Office on eroding rookery islands says. Many of those islands haven't had any new material for years. Birds use them as rookeries to nest and raise chicks in large groups and find protection from predators and human disturbance.

Some historical background is also given in the report. Before the dredging projects of the Gulf Intracoastal Waterway in the early 1900s, birds utilized natural islands. Upon completion of the waterway in the mid-20th century, dredged material was placed along the sides of the waterway, forming new islands that served as replacement rookery sites. But few natural processes rebuild beaches there, the same report notes, and those islands began eroding, too. To see how that erosion is playing out more recently, the researchers examined erosion on 186 rookery islands within about 1.5 miles of the waterway, in 10 coastal Texas counties, from 2004 to 2014. They scored each island for the risk of it becoming unsuitable for waterbirds within 5, 10, 25, and 50 years.

A bigger idea

Can this be done on purpose? A study published in the Journal of Environmental Management suggests it can. The authors state that strategic placement of dredge spoil can be an effective tool for preventing habitat loss. They focused on reddish egrets. The study says most of the U.S. breeding population is in Texas, where numbers have plummeted more than 30 percent since the 1970s. These egrets build nests on dredge spoil islands along the Texas coast. The team created a model to demonstrate where new islands in the Laguna Madre would be most beneficial. It is a different place, a different bird from Sundown. So that doesn't prove the same fix works everywhere.

Why this story counts

Many readers might recognize the pressure of a housing shortage. Birds face it too, when the shorelines retreat. On Sundown, the material was already being dug up for shipping. Moving a share of it gave nesting birds a bit more room. However, caution is still warranted. By the Corps' own account, the new land offset erosion for years. Long-term outcomes would require follow-up checks. One project probably isn't going to solve coastal erosion, but it shows how dredged material can be repurposed into nesting habitat.