THE LAST time City Council tried to draw new boundaries for itself, Councilman Rick Mariano threatened to throw a colleague out the window.

Members missed their deadline for redistricting and went without paychecks for five months - a factor in Mariano's decision to let a local business pay his credit-card bills, leading to a four-year prison stretch.

Hold your breath: This year's redistricting battle could be worse.

No one in the current Council lineup has Mariano's flair for combat, and there's no reason to put prosecutors on alert.

But city population shifts over the past 10 years make this year's redistricting problems look tougher than those that Council faced in 2000.

Since political districts must be of near-equal population, after every census the boundaries get redrawn. The new census figures show that most of the city's growth over the past 10 years has been on the eastern side of the city, in the two Council districts that run along the Delaware River, the 1st and the 6th.

Meanwhile, the four districts in West and Northwest Philadelphia - the 3rd, 4th, 8th and 9th - have lost population. They can't extend westward, because they're already on the city boundary, so Council members are forced to look eastward for expansion.

That puts a squeeze on two districts in the middle - the 5th, represented by Darrell Clarke, and the 7th, represented by Maria Quinones-Sanchez.

Both are already viewed as two of the most gerrymandered municipal districts in the nation, with nonsensical boundaries that stretch each of them out for close to nine miles, at various points less than a block wide.

Now those two districts will face unavoidable pressure to shift farther east, undergo further contortion or both, as Council sees fit.

The situation is complicated further by demographics: Quinones-Sanchez is the first Hispanic ever elected to a district Council seat, and Hispanics are the fastest- growing segment of the city's population. But the weird configuration of the 7th district dilutes its Hispanic base and leaves Quinones-Sanchez facing a tough challenge from a non-Hispanic ward leader and former councilman, Tim Savage, in next month's Democratic primary.

"It's not a question of swapping 5,000 voters between one district and another," Quinones-Sanchez said. "It impacts five or six districts, and that's why it becomes complicated."

The city charter requires each Council district to include roughly one-tenth of the city's population, or 152,600 people, according to the Census count delivered last month.

The charter gives Council members six months to get it done, or live without paychecks until the job is complete. That's what happened 10 years ago, and 10 years before that.

Despite calls from the government-watchdog group Committee of Seventy to set up public hearings for input and comment, Council members appear preoccupied with the city budget and the May 17 primary election, and they've unveiled no redistricting schedule so far.

As a candidate, Mayor Nutter urged redistricting reforms, but he's gone silent on the issue as mayor. Eventually, he'll have to sign or veto whatever plan Council develops. So it becomes more likely that the new lines of Council districts will be decided the same way they've been decided in the past - in backroom negotiations during which members will jockey for geography featuring friendly ward leaders, likely campaign donors and political views and demographics similar to the Council members'.

The retirement of four Council members may lend more civility to this year's debate, but the people who win Council nominations in May's primary will likely weigh in, adding to the pressure.

Staff writer Julie Shaw contributed to this report.