By now, shoppers were hoping to hear the rat-tat-tat of a jack hammer breaking ground at Exit 80.

Instead it’s the tap-tap-tap of toes as developers, brokers, retailers and their prospective customers wait impatiently for work to begin. The plan? A 191,000-square-foot Wal-Mart Supercenter and who-knows-how-many other retailers on a 75-acre complex out near Lewiston’s turnpike exit.

The problem? You name it.

New environmental regulations, a state-mandated economic impact study and a squishy national economy all play a part, not only in Lewiston but at other retail sites as well.

Here’s a primer:

• Two new environmental regulations – one that protects urban streams and another that preserves vernal pools – mean more time and money before the spade ever hits the ground.

In the case of vernal pools – those springtime lagoons where critical fauna spawn – timing is everything. A parcel slated for development has to be checked for vernal pools in May. A developer who decides in July that he wants to build will have to wait 10 months before he knows the viability of the site.

“If you have to wait a year before you can test for this, that’s a real problem,” said Charlie Craig, a retail broker with NAI/Dunham Group. “People are delaying on spending money for engineering and things like that because it could be for naught.”

Already affected: The Lewiston Wal-Mart project was ready to break ground last spring, but working out the compliance with the new environmental regs delayed the project until now. Best guess is ground will be broken this spring.

• Maine’s Informed Growth Act, a new law intended to preserve quality of life and restrain sprawl, requires all retail projects 75,000-square-feet (such as Home Depot and Kohl’s) and bigger to undergo an economic impact study. The effect on local jobs, existing retailers, municipal services, the environment and other factors will all be studied by an independent consultant vetted by the State Planning Office. A list of nine-approved consultants was released Dec. 1, six months after the law passed.

The cost: $40,000. The time frame: six months. The problem: more delays in the approval process with the possibility that a study showing a negative impact in any one of the categories can deep-six a project.

• The national economy. Higher fuel bills, a credit crunch, plummeting consumer confidence … all are making shoppers think twice about opening their wallets. Retailers react by stalling – setting expansion plans aside and adopting a wait-and-see attitude. On the corporate level, Wal-Mart and Home Depot have already scaled back their expansions plans; others are following suit. A Maine example: Kohl’s is waiting to see how its Biddeford store is going to perform before it commits to building in other secondary markets, said Craig.