It sent a 40-foot-high wall of water toward St. George, making 1,500 New Year's revelers scramble for high ground early in the morning. No one died, but 50 to 60 homes were destroyed or damaged, and hundreds of livestock animals were killed.

Marble said all that created political pressure to improve Utah's dam safety program. The Legislature passed a law in 1990 aimed at improving safety. Among other things, it led to studies that raised minimum standards for dam safety. It also required dam owners to perform studies of what steps are needed to bring their dams up to those higher standards.

With concern that resulting repair costs could bankrupt some dam owners, the Legislature passed a law saying the state could not order upgrades to dams until the state offered a grant covering at least 80 percent of the cost.

Since then, the state has awarded more than $40 million in grants to help upgrade or replace dangerous local dams. Such construction has been completed at 21 "unsafe" locally owned dams and is ongoing at three others. Meanwhile, work at 118 other "unsafe," state-inspected dams is awaiting funding.

Additionally, the federal government owns or inspects 25 high hazard dams in Utah — and says they meet safety standards or are undergoing construction to meet them. Many of those federal dams also have been repaired or upgraded in recent years.

Are cities safe?

The state developed a risk rating system to identify and prioritize for repair those dams that it considers to be unsafe. Results show that the most heavily populated areas in Utah also have the most "unsafe" dams.

Salt Lake County has 18. Utah County is close behind with 16, and Davis County is third with 11. All counties except Daggett, Kane and Grand have at least one unsafe dam.

The city with the most "unsafe" dams immediately above it — eight — also happens to be the state's largest: Salt Lake City.

Unsafe dams in or immediately upstream from Salt Lake City include: Rotary Glen Park Dam; Red Pine Dam; Red Butte Dam; Chandler Drive Dam; School Pond Dam; Sugarhouse Dam; Federal Heights Dam; and Shriners Dam.

Sandy in Salt Lake County has the second-most "unsafe" dams above it, seven.

Heber, Payson and Whiterocks (Duchesne County) each have four unsafe dams immediately above them.

Six cities have three "unsafe" dams immediately above them: Bountiful, Center Creek (Wasatch County), Centerville, Huntington, Kaysville and Provo.

Eleven cities have two "unsafe" dams immediately above them. And 50 sit beneath at least one unsafe dam. (See accompanying charts for a list, location and rating of all unsafe dams.)

Dangerous data hole