2002 Hayman Fire and the
Cheesman Area Reclamation
 

Severely burned area near Cheesman, June 28, 2002.

Colorado's largest-ever forest fire, the Hayman fire of 2002, seared through major portions of Denver Water's watershed, charring the land and scorching the forest surrounding one of Denver Water's most valuable and vulnerable assets: Cheesman Reservoir.

The blaze started June 8, 2002, near Tarryall Creek, about 11 miles southwest of Cheesman. Driven by fierce winds, the fire reached Cheesman the next day, incinerating nearly all 7,200 forested acres of Denver Water land surrounding the reservoir. In twenty days, the fire ultimately burned 138,000 acres, destroyed 132 homes, devastated a treasured national forest, and put the workhorse of Denver's water system at risk.

Over the following year, Denver Water crews worked tirelessly to prepare the forest in the short term for what Mother Nature must accomplish in the longer term: the recovery of an ecosystem.

"The Colorado State Forest Service has estimated that it will take 150 years for the forest itself to be re-established,"

The work of rehabilitation begins. Crews repair the Goose Creek road.

said Beth Roman, an analyst in Denver Water's Source of Supply section, in 2003. "However, vegetation and groundcover can come in relatively quickly and that's where we are now concentrating our efforts."

"Since vegetation at Cheesman was completely wiped out, erosion occurs at a much faster rate than normal," Roman said. The soil surrounding Cheesman for the most part consists of crushed or granulated granite. Additionally, the heat of the fire created hydrophobic soil conditions that resist water absorption. These three factors made the area a perfect candidate for flash-flooding and serious erosion during heavy rainfalls.

Erosion is a water system's biggest problem when a previously forested area has become completely devoid of vegetation, Roman explained. "Not only does erosion change the landscape and disturb growth of vegetation, but it also causes massive loads of sediments to move into the water supply. Sediments can clog the outlet works of the dam, reduce the storage capacity of the reservoir, and foul the water. Cheesman is Denver's main operating reservoir, thus making restoration of the area a certain priority for Denver Water."

In the year immediately after the fire, the following restorative efforts took place at the Cheesman Reservoir property:

• Denver Water crews and aerial contractors applied more than 210,000 pounds of grass seed over 4,550 acres and sprayed hydromulch over an additional 450 acres.
• Nearly 30,000 straw bales were placed to create nearly 2,000 sediment dams to slow down the flow of rain runoff in gullies.
• Crews cut dead timber on steep slopes in the burn area using a process called "contour felling' in which trees are cut and aligned perpendicular to the slopes, again to prevent erosion.
• Denver Water also hired contractors with HydroAx machines to mulch standing dead trees on approximately 2100 acres.

  HydroAx at work.

  This process helps break up the hydrophobic soils, removes the unstable burned trees from the landscape, and returns organic materials to the soil. Much of this was done in areas that were already seeded, so it provided mulch over the seed.
• Under private contract, 1700 acres of burned land were logged by timber salvage companies. About 10 million board feet of lumber, the equivalent of 22,000 cords of firewood or 2,900 miles of 2x4 studs, were salvaged and trucked to mills in Montrose to provide framing for new homes.

"We learned our lesson from Strontia Springs and the Buffalo Creek fire," Roman said, referring to the 1996 fire and flood at Buffalo Creek that washed 600,000 cubic yards of sediment into Denver Water's Strontia Springs Reservoir. "The difference this time is that we own a large perimeter of land in the burned area around Cheesman Reservoir, enabling us to really do something to counter the effects of this fire on our watershed."

Denver Water continues to reestablish the forest wiped out by the fire. Denver Water planted 25,000 Ponderosa Pine seedlings in the summer of 2003, and another 25,000 each summer since. We will continue to reforest the area with native pine species for the next 9 years.

As a more immediate source of protection for the dam and the water supply, a 140-foot-long, 40-foot-high rock sediment trap was constructed in 2003 to span the Goose Creek inlet, northwest of the dam. The structure contains about 14,000 tons of rock and is designed to be water-permeable. This trap slows the flow of water from Goose Creek into Cheesman, allowing sediment to settle out behind the trap instead of flowing directly into the reservoir. This summer (2005) crews dredged more than 5,000 cubic yards of sediment from the trap.

In 2004 a similar structure was built at Turkey Creek, on the southeast corner of Cheesman Reservoir. Dredging removed 24,000 cubic yards from this trap in 2005. (More on the sediment trap projects at Cheesman.)

The cost of the first year of Cheesman reclamation totaled more than $5 million, with the U.S. Natural Resources Conservation Service and the Environmental Protection Agency reimbursing Denver Water approximately $2.8 million of that amount. Between 2003 and 2005, Denver Water has spent about another $3 million on the Cheesman rehab. The cost of rehabilitating the entire 138,000 acres, of which the Cheesman property is only a small percentage, will exceed $100 million, as estimated by the Coalition for the Upper South Platte (http://www.uppersouthplatte.net). Since August 2005, the cost has been nearly $40 million.

Turkey Creek, July 14, 2004