More than 10,000 miles of canals dredged largely by the oil and gas industry crisscross Louisiana’s coastal wetlands, eating away at the state’s fragile coast, but over the decades only 35 miles have been backfilled.

A new project at the Jean Lafitte National Historical Park and Preserve Barataria Unit will add an additional 16.5 miles of backfill to that total, but construction is at least a year away.

Although it’s a drop in the bucket to correct coastal erosion, this project will have a positive effect on the park itself, park officials said Monday.

The $8.7 million project’s funding comes from the settlement of the 2010 Deepwater Horizon disaster.

On Monday, U.S. Department of the Interior Secretary Sally Jewell got an update of how this project can help in the fight against coastal land loss, touring previous backfilling at the park.

Canals were dredged primarily to accommodate oil and gas exploration and pipelines.

These canals not only disrupt the salinity of the freshwater marsh by providing a quicker conduit for salty Gulf of Mexico water to reach inland, they also have higher spoil banks on either side, hampering the normal flow of water over the marsh.

Backfilling these canals means pushing these spoil banks into the waterway. Although the canals aren’t completely filled, the spoil does provide a better base for wetland plants to take hold, which in turn traps more sediment.

On Monday’s trip to the park’s interior, the airboat cruised along a canal lined with trees, indicating high ground, before emerging into wide open marsh. This was a site of a previous project that took down the spoil banks along the canal and opened up uninterrupted marsh to the water’s edge.

“It makes a huge difference,” said Dusty Pate, natural resource program manager for the park. “It’s amazing how quickly it recovers. Give this place half a chance and it grows.”

Many of the canals were dredged in the 1950s and 1960s, long before the area became a park in 1978. The property was purchased “as is,” after many of the wells were plugged and the canals abandoned. As such, the canals remain, except for the 6.6 miles of canal the park has already backfilled.

Concern about the damage that canals could do to wetlands dates back for decades. In the 1980s there were attempts at legislation to get backfilling done and a report was issued from the state Department of Natural Resources saying backfilling of canals should be a matter of course; however, nothing came of either.

Much later, the Southeast Louisiana Flood Protection Authority-East filed a lawsuit in 2013, followed later by individual parishes to get the courts to force oil and gas companies to pay for damage to coastal wetlands caused by canal dredging. Those lawsuits are still working their way through the courts.

Jewell asked Monday whether responsible parties are being made to pay for restoring the areas damaged by the canals, in addition to the money provided through the Deepwater Horizon oil settlement.

“We’re working on it,” said Johnny Bradberry, executive assistant to the governor for coastal activities.

Justin Ehrenwerth, executive director of the Gulf Coast Ecosystem Restoration Council, said that’s a conversation they’re hoping to have with the industry.

“We’re not going to get this all done with the money we get appropriated from Congress,” agreed Jewell.

In the meantime, projects like the one at Jean Lafitte park are expected to repair some of the damage. Elsewhere in the state, dirt is being pumped into some coastal areas, but there’s no widespread effort to backfill canals for coastal restoration purposes.

The new project will take a little time to get on the ground as the Department of the Interior and the park work through what kind of monitoring of the project should be conducted.

Once that decision is made, there will likely be a year of monitoring to lay the groundwork, so to speak, of comparing current conditions with conditions after the work is complete, Pate said. Once a construction date is set, construction should take only six months to complete.

“This project is particularly exciting for us,” Ehrenwerth said of the Gulf Council, which approved the work.

Many of the oil and gas canals are leftovers from a time when there was little regulation of activities in the wetlands. However, there are signs that some companies have made a change.

Looking over a large expanse of freshwater marsh, it’s almost impossible to tell where the Shell pipeline is located. It was built using a small ditch and then was immediately filled over, allowing the natural flow of water to continue and the marsh to flourish.

Follow Amy Wold on Twitter, @awold10.