Last summer, nearly 90,000 fires burned more than 7 million ac. in the United States, according to the National Interagency Fire Center. After the fires swept through, another battle began. Firefighters, government employees, contractors, and volunteers worked countless hours on erosion control and rehabilitation.Floods a Real PossibilityThere is reason to fear flood after a wildfire. In May 1996, a fire burned about 12,000 ac. around the small town of Buffalo Creek, CO. Some erosion control measures, including terracing and reseeding, were performed, but before the plants could provide enough cover, a heavy rainstorm occurred. About 2.5 in. of rain fell, causing severe flooding. Two people lost their lives, the highway to Buffalo Creek was washed out, and several structures were destroyed. The flood also dumped about a 15-year sediment load into Strontia Springs Reservoir, a drinking-water source for the city of Denver. Tom Weber, a resources conservationist with the National Resources Conservation Services (NRCS) in Lakewood, CO, stresses that we can’t prevent erosion. We can only mitigate its effects. But that might protect many lives and properties that would be lost in even a moderate storm compounded by hydrophobic soils and bare hillsides.Task Begins Even as the firefighting efforts continued at each fire, burned-area emergency rehabilitation (BAER) teams moved in to begin their work. BAER teams include experts in soil science, water quality, engineering, and ecology from federal and state agencies. The teams’ main task is identifying immediate dangers from flooding, mudslides, or hazardous tree skeletons. BAER teams follow four steps: aerial mapping of burned areas, field surveys to identify severely burned areas, analysis of flood risk, and reporting on recommended treatments. In some areas, such as Mesa Verde National Park, BAER teams also survey and protect cultural sites. After approval of the treatments, BAER teams coordinate the work. The first task on land denuded by a fire is stabilization of the soils and slopes. The priorities include safeguarding human life and property, protecting municipal watersheds, stabilizing steep slopes, and protecting cultural resources. After stabilization, workers move to long-term rehabilitation, including reseeding native grasses, replanting trees, and preventing noxious-weed growth. Another federal agency that is in the forefront in the rehabilitation of burned land is the NRCS, a part of the US Department of Agriculture. One of its many functions is assisting private landowners after a wildfire. Under the Emergency Watershed Protection (EWP) program, the federal government provides technical knowledge to the landowners, as well as 75% of the cost of erosion control and rehabilitation. The landowners are responsible for the remaining 25% of the cost, which may be in cash or in kind, such as volunteer hours. What Do We Face?The biggest problem after a wildfire is a heavy rainstorm. In much of the western US, thunderstorms in the months of July and August”sometimes called monsoons”provide at least half of the annual precipitation. With trees and vegetation burned off, speeds and amounts of water runoff increase as much as tenfold. The runoff carries dirt, ash, and debris (such as partially burned logs), which clog up waterways, culverts, and reservoirs. The result can be mudslides that destroy homes, buildings, and roads. In severely burned areas, the soil often has a hard shell over it from the rapid burning of vegetation. Because little water soaks into this hydrophobic soil, runoff increases dramatically, causing floods at lower elevations. Lack of time is another concern frequently cited by those involved in postfire rehabilitation and erosion control. Erosion control measures must be in place quickly to mitigate damage from rains and before the scorched soil becomes even more impermeable. “We need to get the seed down when the ash is still fluffy, within about two to three weeks,” says Tim Sullivan of the US Forest Service in Denver.Coordination of all the agencies involved is another concern for these projects. Most of the fires burned over land controlled by as many as four agencies, including the Forest Service, state parks, the Bureau of Land Management (BLM), and the Bureau of Indian Affairs. Add to that dozens of private landowners, and it is a coordination headache. The BAER teams and the work of the NRCS with private landowners has alleviated that problem to a large extent. New Mexico Fires Up
This burned home is one result of the Hi Meadow fire.Surface erosionThe 2000 fire season started in New Mexico. In May and June, several fires burned in forests around the state. The Cerro Grande fire near Los Alamos proved to be the most destructive fire in New Mexico history. More than 47,000 ac. burned beginning on May 4, when a prescribed burn got out of hand in high winds. The devastation included 235 structures and the watershed for Los Alamos. Once the fire was out, an even bigger problem loomed: the possibility of floods or mudslides. BAER Team Leader Wayne Patton states that the team knew it had maybe 40 days until monsoon rains began, increasing the probability of catastrophic floods. Scientists cite evidence of major floods and avalanches that occurred in the last 2,000 years; most of them likely happened after fires. In canyons near town, huge boulders that washed down in the past attest to the power of these floods. So the community, still stunned by the fire, went back to work to prevent more devastation. Prison inmates and volunteers broke up hydrophobic soil with rakes. Helicopters transported workers to high canyons to cut down trees and build check dams. More than 2,000 volunteers worked almost 12,000 hours placing sandbags and straw bales and spreading mulch. Granite Seed in Lehi, UT, provided straw wattles and mulch for the flood control efforts around Los Alamos, as well as for fires in Colorado. According to Bill Agnew of Granite Seed, three factors are important when choosing which measures to use: coverage, longevity, and cost. The coverage provided by wattles is much less than with blankets. Some erosion will occur between the wattles. Then consider the longevity factor. If a wattle lasts one or two seasons, is that long enough? Straw wattles have biodegradable and photosensitive netting. Most will last for two growing seasons, possibly longer in the semiarid climate of New Mexico. By that time, plants should be growing to stabilize the slopes. If the coverage and longevity of the wattles are acceptable, their lower cost might make them the best option. In more critical sections such as drainage channels, however, cost isn’t the most important factor. “You know you have to have longevity even though it is more expensive,” notes Agnew. Erosion control blankets provide the heavier coverage needed to cope with increased water flows. Straw blankets last one season and straw-coconut blankets extend to two seasons. The higher slope coverage of the blankets outweighs their higher cost.In some areas affected by the Cerro Grande fire, immediate reseeding was needed to stabilize the steep slopes. Western States Reclamation Inc. of Broomfield, CO, was contracted for the job. “Efforts were already underway when we got there,” recalls David Chenoweth, president of the company. “Our focus was on steep canyons and remote areas.” His crew of four pilots and support people seeded a total of 1,450 ac. with a slurry of hydromulch, urea fertilizer, and grass seed. The seed used was a mixture of cereal rye, slender wheatgrass, and mountain brome grasses. Guided to the correct sites by global positioning system technology, planes filled with the slurry dropped their loads on slopes too steep to be seeded by truck. In late October, the reseeding effort was evaluated. Chenoweth says the Forest Service was pleased that the grasses were shin-high just before winter set in. The Los Alamos fire was not the only fire in New Mexico in the summer of 2000. Two fires in the southern New Mexico mountains also posed a real threat of flood. The Cree fire near Ruidoso, started by an out-of-control campfire on May 7, burned almost 7,000 ac. of forest and threatened homes. Some homes were near flames that reached as close as their back porches. After the fire was contained, erosion control measures were implemented. BAER Team Leader Greg Gray states that approximately 10,000 straw wattles (nearly 30 semi truckloads ) were staked down onto 50-75% slopes. Contour tree felling was also used, and 40,000 lb. of seed (mountain brome, Western wheatgrass, and yellow blossom sweet clover) was applied to about 5,000 ac. A major concern was the possibility of damage to the roads in the area. Trash racks and jersey barriers were installed to capture large debris and keep it out of road drainages and away from houses. Culverts were reconstructed to handle increased runoff. Six earthen dams had to be rebuilt and strengthened.“We got lucky on the rain,” comments Gray. “We had several slow rains and got a good catch on the erosion control measures.” Because this fire occurred early in the summer, the seed had an excellent chance to grow. Many of the wattles had a stand of green behind them by the end of summer.The Scott Able fire near Cloudcroft, NM, also occurred in mid-May. Most of the same measures were used to protect structures and roads. About five semi truckloads of straw wattles were staked down, as well as contour logs. In canyon bottoms, trash racks, hog-wire and cloth barriers, and jersey barriers were erected to capture large debris. Helicopters reseeded about 5,000 ac. Colorado Turns Up the HeatStraw wattles for slope erosion protectionSeverely burned creek bottomContour tree fellingThe state of Colorado also experienced several fires this past summer. Two fires that burned simultaneously in the mountains west of Denver were the Bobcat fire and the Hi Meadow fire. Both fires started on June 12 and burned for several days, consuming 22,000 ac. The Bobcat fire covered an area very close to the Buffalo Creek fire of 1996, so officials wanted to prevent a repeat of that tragedy if possible. The Bobcat fire burned in an area of granitic soil and abundant rock fragments. The Hi Meadow fire was also in an area of granitic soil with many rock outcroppings that do nothing to slow water. This area is one of the main water sources for many cities in Colorado, including Denver, so sediment control was especially important.After BAER team evaluation of the burn-area severities for both fires, agencies such as the NRCS and both the US and Colorado Forest Service began the rehabilitation effort. The Hi Meadow fire consumed about 11,000 ac., about half of that on national forest land and half under private ownership.The BAER team recommended all available treatments, including contour log felling, directional log felling, straw mulching, wattles, culvert replacement, sandbag terracing, reseeding, and noxious-weed control. Noxious-weed control was not covered by BAER funding and was eliminated, and contour logs and wattles were used in place of sandbags. A crew of 25, with additional volunteer help, carried out the other recommendations. Benita Arellano, a landowner in the Hi Meadow area, has high praise for the work done by the NRCS. Her 35-ac. property, on which she was planning to build a house, was about 70% burned. NRCS implemented straw wattles and contour tree felling on her land and arranged aerial seeding for the area. She and several volunteers carried out hand-raking. With the measures barely in place, the area received an inch of rain, washing out the county road leading to her property. The wattles, however, kept the higher slope from sliding down onto her property. “The damage to my land was minimal,” she reports, “thanks to the good information and help from the NRCS.”Sullivan of the Forest Service says as many as 10 strong storms have occurred in the area since the measures were implemented. “Many of the straw wattles and log terraces are functioning. We consider them successful.” He adds that he would change some things based on monitoring so far. “We would do more directional falling in the channels and low areas. All the swales were running water in the stronger storms, and the trees felled in the swales are very effective in retaining sediment.”Weber of the NRCS agrees that the overall effort was a success. “We got a month’s worth of work done before the rain.” Two storms each released about 2 in. of rain in a matter of hours in the Hi Meadow area, causing some gully washing, but areas of sheet and slope erosion were prevented from becoming gullies.One of the rainstorms that hit this area in August washed out the access road to two neighborhoods. It was a heavy precipitation, about 3 in. in an hour. The Miller Fork and Big Thompson River ran black with ash after the storm. The devastation would almost certainly have been much worse if there had not been time to install the erosion control measures. Mesa Verde National Park was struck by two fires during the summer of 2000. The first one started by lightning strike on July 20 and eventually burned 23,000 ac., closing the park to visitors. This included land under the BLM and land on the Ute Reservation. Because of the site, extra attention had to be taken to protect cultural sites that were uncovered by the fire. Archaeologists hiked along with fire teams to spot these cultural treasures. The park reopened on August 4 but had to close again that evening because of another fire. After the fires were contained, a BAER team began the work to preserve the sites. Erosion control blankets were placed around historic sites, and sheets of metal were tacked over the sites until they could be studied more thoroughly. Montana and Idaho Take the BruntAbout a third of the fires in the West this past summer hit Montana and Idaho. These fires started much later in the season, from July into October. After fires had burned more than 300,000 ac. east of Helena, firefighters switched to rehabilitation efforts. The Bitterroot Interagency Recovery Team handled the coordination of the work and was joined by volunteers from the Montana Conservation Corps, an organization that uses young people to work on projects to enhance the state’s resources. With guidance from the BAER team, these crews dug a diversion ditch to guide water and debris into Magpie Gulch and away from a historic log cabin belonging to the Forest Service. Other members of the Montana Conservation Corps worked to clear debris out of gullies and other drainage systems. In a storm, the debris could wedge together and form a makeshift dam. Eventually it would likely break and cause even more destruction. In southwest Montana, the Army Corps of Engineers handled some of the rehabilitation work. More than a dozen excavators worked to replace culverts before the winter season began. Several hundred volunteers worked along with trained crews to place straw wattles, mulch, and woody debris to stabilize hillsides. John Blaine of the NRCS in Hamilton, MT, explains that sandbags were lined up on creekbanks to protect homes in the area. Many of the homes are on 20-ac. sites and accessible by roads running over bridges. These bridges had to be investigated. Many of them had weakened supports and were reinforced with rock. Log barriers, check dams, and concrete barriers were also placed around homes. Some people were apprehensive about these measures because of their lack of beauty. One of the NRCS’s tasks was explaining the necessity of the barriers and the possibility of catastrophic flooding or mudslides.Because much of the water supply in this area is from wells, some wellhead protection was performed, mostly in the form of barriers or straw bales. Contour silt traps were also installed.Straw bale dam at Dixon CreekSeeding, straw mulch, and a straw erosion barrier above a Dixon Creek home A soil scientist checks for hydrophobicity.About 5,500 ac. of the burned land was reseeded, and herbicide treatment for knapweed was performed. Knapweed is a noxious plant that moves into damaged land, such as burned areas, and forces out any native plants trying to get a start. Because of the later time of these fires in Montana, the seed that was spread was in the dormant state. “We won’t really know results until spring,” Blaine says. “If we get a big snow year and then a chinook [warm wind] comes along or a heavy rain on top of the snow, we could still have some significant problems.” One of the native plants of this area, lodgepole pine, actually needs fire to reseed itself. After a fire, the cones pop open and spread the seeds. It will be years before this process produces stands of trees, however.NRCS personnel confronted a demanding challenge on landowner Lynda Dyche’s 80 ac. near Dixon Creek, MT. The ground had suffered a severe-burn intensity, and only five trees were left standing. The road to the property has stretches that climb a 45º slope. The property also contains three springs that are the water source for a cabin that Dyche was planning. The EWP program added culverts and built berms and rolling dips to protect the road. A 1.5-in. rain that fell during the process almost washed out the road, but heavy snow since installation of the EC measures has soaked into the ground. The springs were protected by contour log felling in the draws leading to the springs. The area was reseeded, but it will be June before the stand of grass can be determined. Dyche also plans to replant trees. “So far, I’m very impressed,” she remarks. “They did a remarkable amount of work, and they keep coming back to see how it’s doing.”In central Idaho, the Clear Creek fire burned more than 200,000 ac.”the largest fire in 2000. The fire was late in the year, so results from EC measures will be evaluated later. Snow was already falling while firefighters were containing the fire. In some areas, the Forest Service has shored up roads so they won’t be washed away or undermined by erosion. Along the Salmon River the vegetation burned, so the river fills with mud after a rainstorm. Volunteers were recruited to harvest sagebrush and rabbitbrush seed. The seeds will be dried and then replanted by helicopter during the winter. “That technique offers the best chance for the seeds to get established in the spring,” says Fish and Game Department Volunteer Coordinator Mary Dudley. Volunteers will also be planting thousands of bitterbrush seedlings. These shrubs have deep root systems that help stabilize the soil in the burned areas.EC Measures: Same and DifferentThe EC measures used in all these fires have many similarities. Most BAER teams recommended and then used straw wattles, contour logs, directional logs, straw bales, mulch, and blankets. Most also replaced culverts and built check dams. All have carried out reseeding. The differences come in with the timing of the work and the results. Because the fires in New Mexico occurred early in the summer, it is possible to see already that the reseeding efforts have been a success. In Montana and Idaho, the reseeding process had to use dormant seed, so results will not be known until the spring warm-up. Long-Term ResultsFor long-term results, we must look at fires from earlier years. In 1996, after a fire hit Mesa Verde National Park, a BAER team deployed EC measures to mitigate further damage and preserve the sites that were revealed by the fire. In 1999, the team met to evaluate their success. They concluded that the sites had been protected and that the reseeding had stabilized and restored the watershed. Four years ago, the 8th Street Fire near Boise, ID, charred 15,000 ac. BLM crews performed EC measures and reseeded the area with native plants before noxious weeds moved in. The plants grew well and prevented what could have been a serious flooding problem in Boise.The FutureThere will be more fires in the future, some of them burning thousands of acres with high intensity. EC professionals need to move in and do their best to mitigate damage from floods. Lessons learned from past fires can be applied to future fires and increase flood and erosion control.
