State prison officials blame a stunning increase in violence and lockdowns on mushrooming gang activity and budget cuts that reduced programs to keep inmates out of trouble.

Corrections chief Ari Zavaras outlined statistics in a briefing to state lawmakers.

Prisons were locked down 148 times in the 2007-08 fiscal year, an 80 percent increase with 66 more lockdowns than in the previous fiscal year, Zavaras said.

Assaults by inmates on other inmates rose 19.5 percent and assaults by inmates on staff went up 11 percent, he said.

The corrections chief said more high-security cells are needed to isolate problem offenders from the general population.

"In the last eight years, the gang population increased by 85 percent while our inmate population only increased by 42 percent," said prison spokeswoman Katherine Sanguinetti. More than 9,300 inmates of the total prison population of 23,000 are identified as gang members or affiliates, she said.

Many inmates bring their gang affiliations - and rivalries - with them. Others join gangs in prison for protection.

Sanguinetti said efforts are made to keep rival gang members away from each other, but with such high levels of gang affiliation, "they are going to run into each other more frequently."

More violence means more lockdowns, she said.

"When we have an increase of violence, lockdown is one of the ways we manage that and keep inmates from injuring each other or staff." It's costly, but sometimes necessary, she said.

The need for high-security cells will be addressed by a new prison in Canon City, but its completion has been delayed until fiscal year 2010-11 in a move to cut $17 million from the prison budget, Sanguinetti said.

"When the existing (maximum security) Colorado State Penitentiary opened, we had a 66 percent reduction in violence through the system," she said. "We expect the same effect when the new one opens."

Until then, troublemakers must be "managed in the general population, and they continue to be disruptive," she said.

From 2001 to 2003, Sanguinetti said, the corrections budget was slashed by $56 million, and 588 full-time prison employees were cut. Although 80 of the cut positions have been restored, she said, "we still haven't recovered from that."

"Along with them, we lost a lot of education, programs and treatment for inmates," she said. "One of the key principles of offender management is to keep them busy because they are less likely to be destructive."

Inmates also aren't getting programs designed to change their behavior such as one in which staff took photos of prisoners that were printed and sent to inmates' families.

Although it doesn't seem like such a program would cost much, Sanguinetti pointed out "when you have 23,000 offenders, costs mount up."

Inmate morale wasn't improved by a cut in prisoner pay from several dollars a day to 60 cents. So-called gate release money given to inmates when they are released from prison has remained at $100 since the 1970s, Sanguinetti said.

An increase in funding for education programs has helped, Sanquinetti said.

Zavaras said 1,364 inmates earned their general equivalency diplomas, or GEDs, during the past fiscal year, about 400 more than the previous year.

Another bit of good news, Zavaras said, is the dramatic decrease in the number of prisoners entering the system.

About 32 inmates a month came into the system in the 2007-08 fiscal year, compared with the usual 100 a month, he said. So far this fiscal year, the number has dropped to 26 a month.

"It definitely is a hopeful trend," Zavaras said. The overall prison population is expected to increase from 23,567 at the end of this fiscal year to 25,558 in 2021.

Attorney general uneasy about prison closures Recently announced plans to close two state prisons won't make the violence worse because those beds wouldn't be used for inmates requiring higher security, prison officials said. But Colorado Attorney General John Suthers said the plan to shut down prisons concerns him. "As someone who has run the Department of Corrections, talk about closing prisons makes me nervous," Suthers said. "Although growth of prison population has slowed, the idea that 10 years from now we're not going to need more prison beds - I find that ludicrous." Plans to close the Colorado Women's Correctional Facility in Canon City and the Rifle Correctional Facility are part of $823 million in budget cuts Gov. Bill Ritter proposed last month. "It's not an ideal situation, but in these budget times, we've got to make hard decisions," said corrections spokeswoman Katherine Sanguinetti. "We were cut back to the bone in 2001-2003 and we have very few options. This is one that meets the business needs of the state without laying off staff." The 192 minimum-security inmates from Rifle would be moved to other low-security facilities or camps that are less expensive to operate than the remote Rifle prison, she said. As for the women's prison at Canon City, Sanguinetti said that population has leveled off and there are 75 empty beds. About 210 inmates will be moved to other women's prisons. The move would save $2.1 million in operating expenses at the women's prison and $600,000 at Rifle, plus $5.5 million from the sale of the Rifle site, Sanguinetti said. A three-month delay in opening the new maximum security prison in Canon City would save $17 million, she said. "I realize there are a lot of competing interests, but public safety has got to be number one," Suthers said, adding that he is hearing from district attorneys around the state who share his concerns. "People that go to prison belong there," said Jefferson County District Attorney Scott Storey. Suthers called prison closures, the sale of the Rifle land and delay in the maximum-security beds "short-sighted." "I personally am nervous about a confluence of trends, with legislators amenable to looking at sentencing reductions and serious budget problems," he said. "This could be a perfect storm that will have some very adverse effects for public safety."