SCARBOROUGH — A federal contractor’s failure to finish dredging the Scarborough River in March jeopardizes boating safety this summer and threatens plans to replenish federally protected shorebird habitat on Western Beach, town officials say.

The future of the $1.7 million dredging project is complicated by the town’s tenuous relationship with the U.S. Fish & Wildlife Service, which holds permitting power over the town’s plan to pump dredged sand onto Western Beach to restore piping plover nesting habitat.

The beach-replenishing plan is vulnerable, said Town Manager Tom Hall, because wildlife officials have indicated that they aren’t satisfied with the town’s recent efforts to increase shorebird protections after an unleashed dog killed a plover chick last July on Pine Point Beach.

The dredging contractor, NALCO – North America Landscaping, Construction & Dredge Co. – removed only 16,000 of 115,000 cubic yards of sand that it was hired to clear from the river’s navigational channel by March 31, according to the U.S. Army Corps of Engineers. The contractor had to stop dredging before plover nesting season started.

As a result, the sand-clogged channel remains largely impassable at low tide, making life difficult and often dangerous for about 35 commercial fishermen and 185 recreational boaters who call the river home, and more than 100 transient boaters who visit the harbor on busy summer weekends.

“It’s going to be tough,” said Dave Corbeau, Scarborough’s marine resource officer. “Fishermen can’t get in and out at low tide. Even Jet Skis have trouble. It limits access and it can be unsafe when boaters run aground. Hopefully, no one gets hurt.”

Army Corps officials will say little about the dredging project because of legal concerns.

NALCO was expected to start dredging by Jan. 6 but didn’t start until mid-February, Corbeau has said. Foul weather, tidal surges and several equipment breakdowns put the company further behind. Corbeau also noted that NALCO didn’t work round the clock, as other dredging companies have done in the past.

The Army Corps actually had planned to start the dredging project in November, at the end of the shorebird protection season, which runs from April 1 through Oct. 31, said Michael Walsh, a navigation project manager for the corps. But another company contested NALCO’s low bid, so the contract wasn’t awarded until December, he said.

NALCO has “performed adequately” on other Army Corps projects, Walsh has said, but they were smaller jobs that didn’t have such critical deadlines and weren’t “on the Maine coast in the middle of winter.”

NALCO has not responded to repeated telephone calls for comment.

The Army Corps intends to resume dredging in November, at the conclusion of the shorebird protection season, according to email comments from Walsh.

It remains unclear, however, which company will finish the job and whether it will be allowed to pump additional sand onto Western Beach.

Town officials say Walsh has assured them that NALCO won’t be back, but transferring the contract to another dredging company requires legal wrangling with the bonding agency that ensured the successful completion of the project.

Permission to continue pumping dredged sand onto Western Beach is up in the air because federal wildlife officials have indicated that the town has fallen short in recent efforts to increase shorebird protections, Hall said. Permission initially was granted through the Maine Department of Inland Fisheries and the U.S. Fish & Wildlife Service, effective annually from April 1 through Sept. 30 from 2014 to 2016.

If wildlife officials don’t readily allow the beach-replenishing plan to continue, Hall said, the Army Corps could decide to barge the sand out to sea, as it often does, and the town would lose an opportunity to refurbish Western Beach, much of which has washed away in recent years.

“If (wildlife officials are) going to be difficult about it, the Army Corps is likely to take the path of least resistance,” Hall said.

On May 7, the Town Council approved a variety of beach- and dog-related ordinance changes intended to increase shorebird protections and raise public awareness. The controversial changes were drafted to avoid a $12,000 federal fine for the plover-killing incident.

From April 1 through Labor Day, dogs are either banned or must be leashed in restricted areas of Higgins, Ferry, Western and Pine Point beaches where piping plovers are known to be nesting. From May 15 through Labor Day, dogs are banned on all beaches from 9 a.m. to 5 p.m. and from dusk to dawn. During this period, dogs can be in non-restricted areas unleashed but under voice and sight control from dawn to 9 a.m., and leashed from 5 p.m. to dusk. From the day after Labor Day through May 14, dogs must be leashed on beaches from 1 p.m. to 3 p.m.

In addition, the town is spending $24,000 a year on additional staff, including a new beach monitoring coordinator, to increase oversight of plover and dog activities. It also established staff training, volunteer monitoring and plover chick protection programs.

To further increase public awareness, the town has installed new signs, published two new pamphlets on dog and beach regulations and created a Facebook page – Scarborough Piping Plover Monitoring – to keep residents and visitors informed about piping plover activities.

Federal wildlife officials are reviewing the town’s latest actions to determine whether they satisfy a settlement agreement that was drawn up to avoid the $12,000 fine, said Meagan Racey, spokeswoman for the U.S. Fish & Wildlife Service.

Racey said the town has been in breach of that agreement since Scarborough voters overturned previously approved ordinance changes in a December 2013 referendum. Still, she said, town officials have demonstrated “good faith” and “genuine interest in continuing efforts to conserve the threatened piping plover.”

Asked whether her agency might withdraw permission to pump sand onto Western Beach, Racey said the beach-replenishing plan has been viewed as a positive move.

“We are still reviewing the town’s ordinance and beach management program,” Racey said in an email. “The results of our review are connected to our coordination with the (Army Corps) on their project.”