Construction work began on Mt. Auburn St. yesterday morning, as the city continued the latest phase of its massive sewer remodeling project.

And the work on DeWolfe St. that had taken much of the summer was "essentially completed" Friday, according to project coordinator Brian C. Culver, allowing the street to be reopened to traffic.

The Mt. Auburn St. project, however, will not stop as much traffic as work on DeWolfe St. did--one lane of traffic will remain open on Mt. Auburn St. until the project is completed sometime late next month, Culver said.

Also yesterday, Holyoke Place--the short street off Mt. Auburn St. leading up to Lowell House--was closed for two weeks for sewer renovation.

The castle of the Harvard Lampoon--a semi-secret Bow St. social organization that rarely publishes a so-called humor magazine--seems to be a focal point of the latest renovations.

Over the past two months, more and more large cement pipes have sprung up around the sides of the building. Recently, blockades and gravel were put infront of the castle, and a bulldozer was spotteddumping yet more gravel in the area yesterday.

Nearby on Bow St. on the side of St. Paul'sCatholic Church, dirt and bulldozers have markedthe site of even more work for more than a weeknow.

Yellow ribbons labeled "caution" warnedpedestrians not to cross Mt. Auburn St.yesterday--making visits to Tommy's House of Pizzaand Sage Jr.'s slightly more inconvenient.

By the end of the summer, Plympton St. and MillSt. will also see renovations.

But all the major sewer renovations below theUniversity's streets will be done in time for fallregistration, Culver said in an interview Friday.

The latest ren@[ions are part of the finalphase of a 25-year Cambridge sewer renovationproject that will involve all of the Square by thetime the completion date arrives.

In this sixth phase of the project, which wasinitiated in October 1993, workers will constructthe main trunk of a storm sewer from the CharlesRiver up DeWolfe St.

The trunk will be extended beyond Quincy Squareup Quincy St. to Kirkland St. and Memorial Hall,Culver said.

The present work is just one of three contractsin phase six of the project.

The contractor forecasts completion of theproject by March, 1995, Culver said, and theproject is presently more than 50 percent done.

But the contract will be "essentiallycompleted"--i.e., all work excepting minorrepairs--by the fall of this year.