NEWBURYPORT — When the day comes when 200-plus parking spaces disappear from the waterfront, where will all those cars go?

That's the crux of the problem facing the city as the Newburyport Redevelopment Authority's consultant firm, the Cecil Group, narrows in on a new plan for the waterfront. NRA chairman Nat Norton said the NRA has provided the public's comments from the meeting in September on concepts "A" and "B" to the firm, which will be coming up with a final concept in the next few weeks.

There's currently about 360 spaces in the waterfront lots; under the two plans, one would cut it down to 123, the other has 137.

Over the course of 13 months, The Daily News studied parking patterns in the city's major downtown lots - including the NRA's two waterfront lots — and the data indicates capping parking at 123 to 137 spots would often cause congestion and serious parking problems in the downtown.

Of the months studied by The Daily News, six months were problematic. Three of those months posted averages that exceeded 137 cars in the waterfront lots, and three months had between 124 and 132 cars in the waterfront lots — meaning that if there were only 137 parking spots on the waterfront, they would have been over 90 percent full.

The busiest period was June of 2008, when an average of 212 cars were parked in the waterfront lots every day. The Green Street lot during that time averaged 93 percent full, leaving little room for parking relief.

Those figures don't jibe with the NRA's estimates.

"It's our observation that the parking we'll be removing is not actually used on any regular basis," Norton said. "The East lot is under-utilized — as parking spaces are eliminated, it shouldn't have a huge impact."

Some say a parking garage is needed to combat parking woes, while others dread the thought of such a large structure dominating the quaint landscape. NRA member and City Council President James Shanley said a garage should be a case of last resort, as it has many other built-in expenses, like maintenance and staffing.

"Based on my previous work volunteering with various parking committees, there are parcels of land in the city in which a parking garage could fit or make sense, but it's really up to the city," Norton said. "It appears there's a demand for parking in other areas of the city, like upper State Street, but the supply is on the waterfront. The city has the right number of parking spaces, just in the wrong places." Shanley agreed, saying that the city should consider paid parking, with higher demand areas costing more.

"What I think the best way to approach it would be to develop a parking benefit district, which is a concept that's developed in California," Shanley said. "The money that is generated from parking fees gets plowed back into the area where it came from. All or part of the money collected would go back into the neighborhood itself, for sidewalk and lighting upgrades, street sweeping and flowers."

Shanley said he's floated the idea, but has received resistance because residents are so used to having free parking.

"The point of paid parking isn't to make a lot of money, it's to ensure parking turnover," Shanley said. "Fundamentally, there is no such thing as free parking — there's a cost involved with anything in life and when something is free, usually that cost is just deferred or paid for by someone else."