Rowers in this weekend's Head of the Charles Regatta will compete in the cleanest river in the event's history, the Environmental Protection Agency (EPA) announced earlier this week.

As the University makes its final preparations for the event, the EPA announced that the Charles "is clean enough for boating almost all the time and clean enough for swimming a great majority of the time."

EPA administrator John P. DeVillars said the report was timed carefully.

"We did this on purpose," he said. "We know that this is a time when people are focused on the River."

The EPA deemed the River this year suitable for boating 91 percent of the time, up from 39 percent in 1995. Its improvement in "swimmability" is even greater--a jump from 19 to 75 percent.

Regatta participants and others in the community have long had concerns about pollutants in the river. On Earth Day last year, Harvard joined the EPA and other universities and firms in formally resolving to clean up the Charles.

Before the regatta weekend in 1996, heavy rains caused sewers and storm drains to flow into the river.

"[The regatta] was cancelled because of the weather, but there were concerns about water quality." DeVillars said.

Others were concerned about the possibility of blood poisoning among rowers, whose blisters often come into contact with the River's unclean waters.

Three years ago, at least one first-year rower sustained blood poisoning after contact with the water, according to Edward Kloman, Women's Lightweight coach.

But now, Kloman described the river's current condition as "immaculate."

Still, many say they aren't satisfied with the water quality.

"It's been getting a little better every year," said Women's Heavyweight coach Liz O'Leary, but she points out that the Weld boathouse still raises red or blue flags every day to indicate water quality.

To reach its goal--"to make the river fishable and swimmable by Earth Day 2005" --the EPA announced it will allocate $200,000 in additional projects.

For Harvard, preparing for the some 200,000 visitors to the area each year calls for tightened security on the weekend of the regatta.

Gates leading to the Houses and to the Yard will be monitored, and students will only be allowed to enter with a proper ID, according to an announcement from the dean's office,

Students may only have one guest over the weekend, and the guest must be registered with the House office.

Parties this weekend must be registered through the usual process, and some Houses, including Kirkland, have announced that they will not grant permission for any parties this weekend.

Keg deliveries to the Houses will not be permitted.