The construction of a new Wal-Mart Superstore in Scarborough continues to be delayed as the soil beneath the planned building sinks.

The town has yet to issue a building permit for the 212,000-square-foot Wal-Mart because the soil still has not settled more than a year after construction crews loaded it into the wet ground.

A 138,000-square-foot Lowe’s store, also part of the Scarborough Gallery retail development and originally scheduled to be completed in the summer or fall of 2006, is now expected to open this summer.

Engineers behind the two buildings, which are part of the development located between I-295 and Spring Street, are now faced with the daunting task of pumping 15 million gallons of water out of the ground.

When soil is brought in to create a pad for construction of large buildings like a Wal-Mart Superstore, it’s not unusual for the soil to settle between 6 inches and a foot, according to Town Manger Ron Owens. However, the soil has so far sunk 39 inches – and counting.

Before cold weather hit, project engineers had planned on using snow-making machines to turn the water into snow, making it easier to remove. But Mother Nature beat them to it, turning the water into ice before it could be turned into snow.

“How do you remove 15 million gallons of water from the site?” Owens said.

Bringing in soil to compensate for wet soil is not unusual, according to town officials. Other nearby projects, like the Christmas Tree Shop and the Marriott Hotel, have had to use the same process developers of the Lowe’s and Wal-Mart used – a process known as “pre-loading.”

During pre-loading, soils are brought in to create a mound of earth that replicates the weight of the building, said Owens. The soil then settles, compacting the ground underneath the building site by eliminating the moisture.

“Typically, the pad would take a year to settle at most,” Owens said, but more than a year since the pre-loading, the ground is still sinking.

The culprit in this case appears to be Presumpscot clay, according to town Code Enforcement Officer Carroll Shepard. The clay, which holds a lot of water, is causing the ground to take more time to compact.

Although the engineers who tested the soil last summer knew that Presumpscot clay was present, the extent of it was unclear.

“You do your tests and you do your bores, but it’s not an exact science with something as big as Lowe’s or Wal-Mart,” Shepard said.

He said there were other factors at play as well, like the amount of rainfall that occurred last year. Wick drains have been added to remove the moisture, but the process is still moving slowly.

According to Owens and Town Engineer Jim Wendel, there are a few options for removing the water at this point. One is to remove the ice in blocks and relocate it to a gravel pit in Gorham. Another is to add more wick drains to the site.

The third is to “pile” the site, which means to shove sticks in the soil in order to create a frictional force that would be able to hold the weight of the building. According to Wendel, all of the options are either expensive or time-consuming.

“Ultimately, it all comes down to money,” Wendel said.

According to Ben Divine, a representative from KGI Properties, the company that is developing the property, most of the Lowe’s building has been constructed, but the section where lumber will be sold has not yet been built. Construction of Lowe’s was slowed by winter weather and is expected to start back up again in April. It will take two to three months to complete and the store should be open by the summer, according to Divine.

Shepard said that the construction process at Lowe’s will be sped up by the addition of three more feet of pre-load and wick drains that help remove moisture. Wick drains were added to the Wal-Mart plot and, according to Shepard, “it seems to be stabilizing.”

Shepard said that a building permit would have already been issued, but the process was delayed by the Valentine’s Day storm.

“It’s just a matter of time,” Shepard said.

Sinking soil stalls new Scarborough Wal-MartSinking soil stalls new Scarborough Wal-Mart