Controlling Erosion After an Inferno
The San Bernardino experience.
In 2003, southern California experienced one of its worst fire seasons in recent history. By the time the last of the flames were extinguished, the loss of life and property created scars that would last a lifetime. A critical problem was the damage to the watershed that could result in additional losses from floods and debris flows as winter storms began.
In San Bernardino county, CA, two major arson-set blazes resulted in at least seven deaths, destroyed nearly 1,200 homes, and left approximately 150,000 acres of hillsides exposed along a nearly 40-mile frontage. On October 21, 2003, the first of the fires, known as the Grand Prix fire, erupted in the foothills above Rancho Cucamonga. This fire burned 58,448 acres and destroyed 135 homes before it was contained.
On October 25, 2003, at approximately 9:00 a.m., a second arson fire erupted north of the city of San Bernardino. Witnesses reported seeing a white van driving along Highway 18, with the occupants throwing burning papers from the vehicle. By 10:30 a.m., Santa Ana winds had pushed the fire—known as the Old Waterman Canyon fire—into the city's residential neighborhoods, splitting the fire into two separate fronts that moved east toward Highland and west toward Devore. By the next morning, the fire had moved higher into the mountains toward Crestline and Arrowhead, leaving more than 400 homes destroyed and entire neighborhoods devastated within San Bernardino. By the time the fire was contained on October 31, it had burned nearly 1,000 homes and 91,281 acres. Six deaths were attributed to the fire.
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The city of San Bernardino is situated at the base of the San Bernardino Mountains and shares a 15-mile urban-wildlands interface with the San Bernardino National Forest along the northern city limit. Along this 15-mile boundary, numerous canyons empty out of the mountains into the city, each capable of carrying significant amounts of water and debris directly into neighborhoods already impacted by the fires. But more importantly, the threat of flooding extended into areas of the city untouched by the devastation from the fires. With approximately 185,000 residents, the potential for future loss caused by winter storms was significant, and the task of minimizing further damage from floods facing the city's Public Services Department was daunting.
Assessing the Situation
The most immediate issue facing city staff was to assess the total extent of damage that occurred from the fire as it related to infrastructure. With 400 homes destroyed and other significant infrastructure damage, the initial focuses were on reestablishing services, removing debris, and eliminating potential hazards. City crews were dispatched to each of the neighborhoods to inventory public infrastructure damage. Because the city operates its own refuse-collection services, rolloff bins were placed throughout the damaged neighborhoods to provide both physical and psychological assistance to homeowners who literally had nothing but ash to come home to after the evacuation.
While many of the neighboring jurisdictions were still dealing with the actual fires, city staff recognized that resources such as sandbags, straw bales, and concrete barriers (K-rails) could be in limited supply. Orders for significant quantities of empty sandbags were placed almost immediately with various suppliers, and approximately 100,000 bags were received within two weeks of the fire. Other supplies ordered included a truckload of hay bales, sand, and approximately 45 segments of 20-foot-long K-rail. In addition, crews began immediately inspecting and cleaning storm drains, channels, and catch basins throughout the city, with a particular focus on drainage facilities along the northern portion of the city. Coordination meetings with San Bernardino County Flood Control and the City of Highland were held the first week after the fire and joint response planning was begun.
City staff recognized that, given the breadth and extent of the exposure to erosion along the entire mountain range, the likelihood of significant joint resources was limited once the winter rains began. City officials sought additional technical assistance through a variety of sources, including regional engineering firms such as PSOMAS (Costa Mesa, CA) and TransTech (San Bernardino, CA), who performed surveys of potential erosion threat hazards throughout the city. In addition, Mike Harding, a certified professional in erosion and sediment control, provided technical insights into the issues and concerns the city would be facing and offered guidance.
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| Under the watchful eye of the NRCS inspector, city crews install 300 linear feet of K-rails and 100 sandbags in order to redirect excess water and debris from the Meecham Canyon channel, protecting eight homes. |
Harding's past work includes assistance after both the Oakland and Laguna Beach fires, and he is actively involved in many of the soil management activities related to the San Diego fires that occurred during the same period as the fires in San Bernardino. For Harding, the fires of 2003 were significant because of the immensity of the burn area and the need to prioritize the hazards and impacts. "The first thing you notice is that there's a lot of area that's burned, but not all of it is going to have an impact necessarily on people's lives or infrastructure," he observes. "The first thing is to get out and identify what the hazards are—things like debris flows, mud flows, erosion—then to equate that with an actual impact assessment as well, so that you focus your resources in terms of the time, people, and money. Because it's all limited.
"You try and establish priorities," he emphasizes. "Fires in California are naturally occurring phenomena. As a result you get a lot of mud and ash flow. The second thing, particularly around people's homes and infrastructure, is you try and figure out ways to contain that, either through retention structures or—eventually and more effectively—vegetation establishment. You try and find where the water is going, basically, and try and keep that from impacting people's lives."
One of the biggest issues that Harding sees with the fire/flood cycle in southern California is the penchant for building in risk areas. "People build in harm's way," he states. "You go up these canyons and you see all this dry gravel and decomposed granite that's just lying in the bottom of these drainages. It's just waiting to be mobilized. Then you look down below, and people's houses are, in some cases, right in the drainageway. You know the outflow is just going to hit them. I think sometimes people don't understand the hazards of the areas they're building in. I think I know exactly what you need to do to mitigate the next two to three years' worth of erosion and sanitation problems up there, but it really is something that's not related to the fires. You see a lot of things in the field that are pre-existing conditions that are going to be exacerbated by a fire and flood. People need to be thinking about building retention structures or dirt drainage or diversion structures, because these areas are always going to burn at some point in the future. You need to have permanent control mechanisms in place instead of just worrying about going in after these fires and shooting a little mulch."
Providing Resources Before a Disaster
Immediately after any disaster, a variety of federal and state resources become available to assist in the cleanup. For the City of San Bernardino, it was a matter of sorting through the various services offered by the Federal Emergency Management Agency (FEMA) and other agencies. There are often plenty of resources to help clean up after a disaster, but very few programs offer the kind of proactive assistance required to minimize future damage. As the city wrestled with identifying erosion and flood prevention needs and trying to allocate funds for these actions, the message seemed to be clear that unless something was either part of the declared disaster of the fire or a separate disaster, it wouldn't be reimbursable.
In many cities after a disaster, staff is spread thin trying to cope with a multitude of demands, and the number of meetings relating to the disaster multiplies. Such was the case after these two fires. Informational meetings were quickly scheduled in which multitudes of agencies tried to explain the various programs and services that each offered. In one such meeting, held on November 4, 2003, the city became aware of a program that became the centerpiece of its flood and erosion prevention efforts.
The US Department of Agriculture's Natural Resources Conservation Service (NRCS) provides the Emergency Watershed Protection (EWP) program to respond to emergencies created by natural disasters. The program is designed to help people by reducing the imminent hazards to life and property. Two types of assistance are available through this program. The first is for "Urgent and Compelling" circumstances. For this type of assistance, there must be an imminent threat to life and property that requires immediate federal action. Work must generally be completed within five days of accessing the site to protect life and property. The second type is for "Emergency" situations in which the threat to life and property is high enough to constitute an emergency, but is not considered urgent and compelling. The work under this program does not necessarily require immediate action but needs to be completed as soon as possible and within 220 days from start of work. Under both of these programs, the NRCS will pay up to 75% of the costs of the emergency measures. The remaining 25% comes from local sources and can be in the form of cash, in-kind services, or a combination of the two.
"We take a two-pronged approach after the fires," states Jim Earsom, district conservationist with the NRCS's Redlands, CA, office. "The first approach is that we try to look at the watershed and see what citizens are in harm's way, which houses are right below the drainage, and is their protection adequate or not. We have some information in flyers that we leave with them. If, for instance, one of those citizens needs some major measures they're not able to afford, we ask them to contact their local government entity, whether it's the city or the county, and explain to them about our Emergency Watershed Protection program. The second prong of our approach is get with cities, the counties and water districts, and any other special government entity that could go ahead and sponsor that. The EWP program requires that we have a government entity as sponsor that we work through. The sponsor's responsibility is to get the permits and help with the implementation, and then also to come up with 25% of the cost of the measure."
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| K-rail and sandbag installation at 39th Street and Del Rosa Avenue provided significant erosion protection. |
To access the EWP program, the city sent a letter to the NRCS state headquarters located in Davis. According to the NRCS requirements, the letter must be signed by a qualified representative of the sponsoring organization, and should include information on the nature, location, and scope of the problem for which assistance is requested. In this case, the letter stated simply that "We request Federal assistance under provisions of Section 403, Agricultural Credit Act of 1978, to provide emergency assistance to the City … for urgent and compelling threats to life and property as a result of the ‘Old Waterman Canyon' and ‘Grand Prix' fires. Due to the extent and range of the fires, life and property faces immediate threat of flooding and soil erosion along the entire northern boundary of the City." The city administrator as the qualified representative signed the letter, dated November 4, 2003.
Resources to the Rescue
NRCS responded to the city's application and dispatched field personnel to conduct initial assessments on November 12, 2003. Ironically, this was also the same date that a freak storm system pummeled the Watts section of Los Angeles with golf-ball-sized hail, causing massive localized flooding and giving a sense of what San Bernardino could be facing as well.
NRCS staff began preparing Damage Survey Reports (DSRs) that identified the potential threats to property and the actions necessary to minimize those threats. "The Damage Survey Report starts the whole process," says Earsom. "We look at the areas where you might have trouble spots. In a Damage Survey Report we jot down how many residents would be in danger of additional flooding or debris flows that may come from the rainstorm. We document all that and try to come up with some cost estimates of some measures, whether it would be K-rails or a trash rack or a sediment basin. We talk it over with you, of course, and make sure it's something that you would be willing to live with and could work on and maintain. Then we put all that in a DSR, because we have to be able to defend this economically. It doesn't make sense to put in a huge mega-structure, let's say, when we're only protecting a road.
"The program is not meant to install any new things; in other words, it's made to refurbish what you've got or beef it up to withstand the increasing runoff," he explains. "We're not going to pay to put in a new concrete channel or something like that. The other restriction is that it's not for maintenance. Let's say you had a channel and it was full of sediment, and you just hadn't gotten around to cleaning it out. We're not going to pay to have that cleaned out. But if the channel does not have enough capacity to deal with the increased runoff from a storm, we help you beef up that channel and get its capacity back."
The DSRs also assess any environmental issues that may affect the feasibility of installing the recommended mitigations. "If there's some wildlife habitat, maybe we need to have a biologist out there, or maybe we can only do construction at certain times of the year," states Earsom. "We look at those factors, too, and put it all in a package. You sign it and then our state conservationist signs it. After we've done that, then we go to the project agreement. It spells out exactly who's going to do what and the cost. Then we can go ahead, and either you administer the contract or we can make it a federal contract and administer it and get bids to do the project."
According to Earsom, there are three ways in which the project actually can be completed. "One is what we call a force account, where you have your own labor and equipment and are able to do the work," he says. "In a sense, you become the contractor. We would be out there keeping track of all the stuff you had out there, how many people, how much equipment, and then go ahead and reimbursement you for that. Another way, if you didn't want to use your own people, is for you to go out with a local contract and get bids. [The contractor] would do the work, you would monitor it and pay him, and then we'd reimburse you." A third option, Earsom says, is a federal contract: "We do everything. We go out and get the bids, we monitor the work, and when the contractor is done, we pay him. It's really up to the sponsor which way they want to go. It doesn't really matter to us."
Placing Preventive Measures
As a result of the NRCS assistance, work was completed at several locations within the city. The first project, initiated on November 17, involved installing K-rails and sandbags at three locations where there was a significant exposure to debris flows: Belmont Avenue at Meecham Canyon Channel, Irvington Avenue and Chestnut Avenue, and Verdemont Drive at Olive Avenue. At all the locations, there was the potential for excessive runoff to escape from the existing channel and cause significant damage to a total of 18 residential properties. The cost of the emergency work was estimated at $28,260. The NRCS estimated that there was approximately $681,000 of near-term damage possible if the work was not done. The city purchased the materials, and city crews from the Public Services Department Street Division performed the work under the supervision of an NRCS inspector.
The second project, initiated at the same time, consisted of four work items. Locations included Quail Canyon Road, where there was a potential for hillside erosion impacting a small neighborhood. Several homes in the neighborhood had been destroyed by the fire, but several others had been saved. Because of the design of the road, it actually circled above the small neighborhood before descending into Quail Canyon Court, creating an immediate path for mudflow into the remaining homes. The second location involved north Del Rosa Avenue and East 39th Street. Many of the 400 homes that were destroyed were located southwest of this intersection at a lower grade than the street. The city was concerned that debris flows could come down and cause further damage to residents who had already experienced a great deal of loss.
The third location was at north Del Rosa Avenue and Marshall Boulevard, where a flood channel located along the east side of Del Rosa had the potential for overflowing and impacting an apartment complex on the southwest corner. The fourth location was at north Sterling Avenue at Marshall Boulevard, where a box culvert for a flood channel posed the potential of plugging with debris and overflowing. In 1997, this location was plugged with burned materials when a microburst occurred upstream, sending brush and trees downstream. Homes and an apartment complex were damaged from this flooding, so city staff were particularly concerned about this location. The total cost for the proposed work under this second DSR was estimated at $27,475, with the potential to avoid $1,079,293 in estimated damages. The project involved the installation of K-rails, sandbags, and traffic barricades and involved temporarily closing streets at two locations.
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A third project, initiated November 18, consisted of three work items. These locations included north Sepulveda Avenue at 59th Street, where a canyon above a residential neighborhood had the potential for overflowing. The recommended work consisted of installing a rail-and-timber barrier to increase the capacity of a debris basin, and installation of K-rails and sandbags to prevent debris flows from entering several houses located along the west side of Sepulveda Avenue. The second work item consisted of K-rail and sandbag installations to redirect potential flows around residences located in the 300 block of West 59th Street. The third work item consisted of installation of a timber wall around a residence located at West 59th Street and Pershing Avenue. This house was located at the confluence of three canyons that had been burned. Due to some work done by the homeowner, this work item was revised to include installation of K-rail only. The cost for this work was $76,450 to avoid up to $654,694 in potential damage.
All work was completed by mid-December, and its effectiveness was soon tested. On December 25, 2003, a major storm with rainfall of up to 8 inches occurred within the city. In the county areas north of the city, 14 people were killed in Waterman Canyon when a debris and water flow swept over a church camp. In the Devore area at the northernmost tip of the city, a mudflow swept through a KOA campground, killing two people. The city of San Bernardino experienced significant erosion that resulted in streets filling with mud and debris, but in each location where NRCS erosion control measures were in place, damage was kept to a minimum. The work that was performed totaled $132,185 and prevented $2,415,000 worth of damage to the city.
March-April 2005
Controlling Erosion After an Inferno
The San Bernardino experience.
I
n 2003, southern California experienced one of its worst fire seasons in recent history. By the time the last of the flames were extinguished, the loss of life and property created scars that would last a lifetime. A critical problem was the damage to the watershed that could result in additional losses from floods and debris flows as winter storms began.
In San Bernardino county, CA, two major arson-set blazes resulted in at least seven deaths, destroyed nearly 1,200 homes, and left approximately 150,000 acres of hillsides exposed along a nearly 40-mile frontage. On October 21, 2003, the first of the fires, known as the Grand Prix fire, erupted in the foothills above Rancho Cucamonga. This fire burned 58,448 acres and destroyed 135 homes before it was contained.
On October 25, 2003, at approximately 9:00 a.m., a second arson fire erupted north of the city of San Bernardino. Witnesses reported seeing a white van driving along Highway 18, with the occupants throwing burning papers from the vehicle. By 10:30 a.m., Santa Ana winds had pushed the fire—known as the Old Waterman Canyon fire—into the city's residential neighborhoods, splitting the fire into two separate fronts that moved east toward Highland and west toward Devore. By the next morning, the fire had moved higher into the mountains toward Crestline and Arrowhead, leaving more than 400 homes destroyed and entire neighborhoods devastated within San Bernardino. By the time the fire was contained on October 31, it had burned nearly 1,000 homes and 91,281 acres. Six deaths were attributed to the fire.
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The city of San Bernardino is situated at the base of the San Bernardino Mountains and shares a 15-mile urban-wildlands interface with the San Bernardino National Forest along the northern city limit. Along this 15-mile boundary, numerous canyons empty out of the mountains into the city, each capable of carrying significant amounts of water and debris directly into neighborhoods already impacted by the fires. But more importantly, the threat of flooding extended into areas of the city untouched by the devastation from the fires. With approximately 185,000 residents, the potential for future loss caused by winter storms was significant, and the task of minimizing further damage from floods facing the city's Public Services Department was daunting.
Assessing the Situation
The most immediate issue facing city staff was to assess the total extent of damage that occurred from the fire as it related to infrastructure. With 400 homes destroyed and other significant infrastructure damage, the initial focuses were on reestablishing services, removing debris, and eliminating potential hazards. City crews were dispatched to each of the neighborhoods to inventory public infrastructure damage. Because the city operates its own refuse-collection services, rolloff bins were placed throughout the damaged neighborhoods to provide both physical and psychological assistance to homeowners who literally had nothing but ash to come home to after the evacuation.
While many of the neighboring jurisdictions were still dealing with the actual fires, city staff recognized that resources such as sandbags, straw bales, and concrete barriers (K-rails) could be in limited supply. Orders for significant quantities of empty sandbags were placed almost immediately with various suppliers, and approximately 100,000 bags were received within two weeks of the fire. Other supplies ordered included a truckload of hay bales, sand, and approximately 45 segments of 20-foot-long K-rail. In addition, crews began immediately inspecting and cleaning storm drains, channels, and catch basins throughout the city, with a particular focus on drainage facilities along the northern portion of the city. Coordination meetings with San Bernardino County Flood Control and the City of Highland were held the first week after the fire and joint response planning was begun.
City staff recognized that, given the breadth and extent of the exposure to erosion along the entire mountain range, the likelihood of significant joint resources was limited once the winter rains began. City officials sought additional technical assistance through a variety of sources, including regional engineering firms such as PSOMAS (Costa Mesa, CA) and TransTech (San Bernardino, CA), who performed surveys of potential erosion threat hazards throughout the city. In addition, Mike Harding, a certified professional in erosion and sediment control, provided technical insights into the issues and concerns the city would be facing and offered guidance.
|
|
|
| Under the watchful eye of the NRCS inspector, city crews install 300 linear feet of K-rails and 100 sandbags in order to redirect excess water and debris from the Meecham Canyon channel, protecting eight homes. |
Harding's past work includes assistance after both the Oakland and Laguna Beach fires, and he is actively involved in many of the soil management activities related to the San Diego fires that occurred during the same period as the fires in San Bernardino. For Harding, the fires of 2003 were significant because of the immensity of the burn area and the need to prioritize the hazards and impacts. "The first thing you notice is that there's a lot of area that's burned, but not all of it is going to have an impact necessarily on people's lives or infrastructure," he observes. "The first thing is to get out and identify what the hazards are—things like debris flows, mud flows, erosion—then to equate that with an actual impact assessment as well, so that you focus your resources in terms of the time, people, and money. Because it's all limited.
"You try and establish priorities," he emphasizes. "Fires in California are naturally occurring phenomena. As a result you get a lot of mud and ash flow. The second thing, particularly around people's homes and infrastructure, is you try and figure out ways to contain that, either through retention structures or—eventually and more effectively—vegetation establishment. You try and find where the water is going, basically, and try and keep that from impacting people's lives."
One of the biggest issues that Harding sees with the fire/flood cycle in southern California is the penchant for building in risk areas. "People build in harm's way," he states. "You go up these canyons and you see all this dry gravel and decomposed granite that's just lying in the bottom of these drainages. It's just waiting to be mobilized. Then you look down below, and people's houses are, in some cases, right in the drainageway. You know the outflow is just going to hit them. I think sometimes people don't understand the hazards of the areas they're building in. I think I know exactly what you need to do to mitigate the next two to three years' worth of erosion and sanitation problems up there, but it really is something that's not related to the fires. You see a lot of things in the field that are pre-existing conditions that are going to be exacerbated by a fire and flood. People need to be thinking about building retention structures or dirt drainage or diversion structures, because these areas are always going to burn at some point in the future. You need to have permanent control mechanisms in place instead of just worrying about going in after these fires and shooting a little mulch."
Providing Resources Before a Disaster
Immediately after any disaster, a variety of federal and state resources become available to assist in the cleanup. For the City of San Bernardino, it was a matter of sorting through the various services offered by the Federal Emergency Management Agency (FEMA) and other agencies. There are often plenty of resources to help clean up after a disaster, but very few programs offer the kind of proactive assistance required to minimize future damage. As the city wrestled with identifying erosion and flood prevention needs and trying to allocate funds for these actions, the message seemed to be clear that unless something was either part of the declared disaster of the fire or a separate disaster, it wouldn't be reimbursable.
In many cities after a disaster, staff is spread thin trying to cope with a multitude of demands, and the number of meetings relating to the disaster multiplies. Such was the case after these two fires. Informational meetings were quickly scheduled in which multitudes of agencies tried to explain the various programs and services that each offered. In one such meeting, held on November 4, 2003, the city became aware of a program that became the centerpiece of its flood and erosion prevention efforts.
The US Department of Agriculture's Natural Resources Conservation Service (NRCS) provides the Emergency Watershed Protection (EWP) program to respond to emergencies created by natural disasters. The program is designed to help people by reducing the imminent hazards to life and property. Two types of assistance are available through this program. The first is for "Urgent and Compelling" circumstances. For this type of assistance, there must be an imminent threat to life and property that requires immediate federal action. Work must generally be completed within five days of accessing the site to protect life and property. The second type is for "Emergency" situations in which the threat to life and property is high enough to constitute an emergency, but is not considered urgent and compelling. The work under this program does not necessarily require immediate action but needs to be completed as soon as possible and within 220 days from start of work. Under both of these programs, the NRCS will pay up to 75% of the costs of the emergency measures. The remaining 25% comes from local sources and can be in the form of cash, in-kind services, or a combination of the two.
"We take a two-pronged approach after the fires," states Jim Earsom, district conservationist with the NRCS's Redlands, CA, office. "The first approach is that we try to look at the watershed and see what citizens are in harm's way, which houses are right below the drainage, and is their protection adequate or not. We have some information in flyers that we leave with them. If, for instance, one of those citizens needs some major measures they're not able to afford, we ask them to contact their local government entity, whether it's the city or the county, and explain to them about our Emergency Watershed Protection program. The second prong of our approach is get with cities, the counties and water districts, and any other special government entity that could go ahead and sponsor that. The EWP program requires that we have a government entity as sponsor that we work through. The sponsor's responsibility is to get the permits and help with the implementation, and then also to come up with 25% of the cost of the measure."
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| K-rail and sandbag installation at 39th Street and Del Rosa Avenue provided significant erosion protection. |
To access the EWP program, the city sent a letter to the NRCS state headquarters located in Davis. According to the NRCS requirements, the letter must be signed by a qualified representative of the sponsoring organization, and should include information on the nature, location, and scope of the problem for which assistance is requested. In this case, the letter stated simply that "We request Federal assistance under provisions of Section 403, Agricultural Credit Act of 1978, to provide emergency assistance to the City … for urgent and compelling threats to life and property as a result of the ‘Old Waterman Canyon' and ‘Grand Prix' fires. Due to the extent and range of the fires, life and property faces immediate threat of flooding and soil erosion along the entire northern boundary of the City." The city administrator as the qualified representative signed the letter, dated November 4, 2003.
Resources to the Rescue
NRCS responded to the city's application and dispatched field personnel to conduct initial assessments on November 12, 2003. Ironically, this was also the same date that a freak storm system pummeled the Watts section of Los Angeles with golf-ball-sized hail, causing massive localized flooding and giving a sense of what San Bernardino could be facing as well.
NRCS staff began preparing Damage Survey Reports (DSRs) that identified the potential threats to property and the actions necessary to minimize those threats. "The Damage Survey Report starts the whole process," says Earsom. "We look at the areas where you might have trouble spots. In a Damage Survey Report we jot down how many residents would be in danger of additional flooding or debris flows that may come from the rainstorm. We document all that and try to come up with some cost estimates of some measures, whether it would be K-rails or a trash rack or a sediment basin. We talk it over with you, of course, and make sure it's something that you would be willing to live with and could work on and maintain. Then we put all that in a DSR, because we have to be able to defend this economically. It doesn't make sense to put in a huge mega-structure, let's say, when we're only protecting a road.
"The program is not meant to install any new things; in other words, it's made to refurbish what you've got or beef it up to withstand the increasing runoff," he explains. "We're not going to pay to put in a new concrete channel or something like that. The other restriction is that it's not for maintenance. Let's say you had a channel and it was full of sediment, and you just hadn't gotten around to cleaning it out. We're not going to pay to have that cleaned out. But if the channel does not have enough capacity to deal with the increased runoff from a storm, we help you beef up that channel and get its capacity back."
The DSRs also assess any environmental issues that may affect the feasibility of installing the recommended mitigations. "If there's some wildlife habitat, maybe we need to have a biologist out there, or maybe we can only do construction at certain times of the year," states Earsom. "We look at those factors, too, and put it all in a package. You sign it and then our state conservationist signs it. After we've done that, then we go to the project agreement. It spells out exactly who's going to do what and the cost. Then we can go ahead, and either you administer the contract or we can make it a federal contract and administer it and get bids to do the project."
According to Earsom, there are three ways in which the project actually can be completed. "One is what we call a force account, where you have your own labor and equipment and are able to do the work," he says. "In a sense, you become the contractor. We would be out there keeping track of all the stuff you had out there, how many people, how much equipment, and then go ahead and reimbursement you for that. Another way, if you didn't want to use your own people, is for you to go out with a local contract and get bids. [The contractor] would do the work, you would monitor it and pay him, and then we'd reimburse you." A third option, Earsom says, is a federal contract: "We do everything. We go out and get the bids, we monitor the work, and when the contractor is done, we pay him. It's really up to the sponsor which way they want to go. It doesn't really matter to us."
Placing Preventive Measures
As a result of the NRCS assistance, work was completed at several locations within the city. The first project, initiated on November 17, involved installing K-rails and sandbags at three locations where there was a significant exposure to debris flows: Belmont Avenue at Meecham Canyon Channel, Irvington Avenue and Chestnut Avenue, and Verdemont Drive at Olive Avenue. At all the locations, there was the potential for excessive runoff to escape from the existing channel and cause significant damage to a total of 18 residential properties. The cost of the emergency work was estimated at $28,260. The NRCS estimated that there was approximately $681,000 of near-term damage possible if the work was not done. The city purchased the materials, and city crews from the Public Services Department Street Division performed the work under the supervision of an NRCS inspector.
The second project, initiated at the same time, consisted of four work items. Locations included Quail Canyon Road, where there was a potential for hillside erosion impacting a small neighborhood. Several homes in the neighborhood had been destroyed by the fire, but several others had been saved. Because of the design of the road, it actually circled above the small neighborhood before descending into Quail Canyon Court, creating an immediate path for mudflow into the remaining homes. The second location involved north Del Rosa Avenue and East 39th Street. Many of the 400 homes that were destroyed were located southwest of this intersection at a lower grade than the street. The city was concerned that debris flows could come down and cause further damage to residents who had already experienced a great deal of loss.
The third location was at north Del Rosa Avenue and Marshall Boulevard, where a flood channel located along the east side of Del Rosa had the potential for overflowing and impacting an apartment complex on the southwest corner. The fourth location was at north Sterling Avenue at Marshall Boulevard, where a box culvert for a flood channel posed the potential of plugging with debris and overflowing. In 1997, this location was plugged with burned materials when a microburst occurred upstream, sending brush and trees downstream. Homes and an apartment complex were damaged from this flooding, so city staff were particularly concerned about this location. The total cost for the proposed work under this second DSR was estimated at $27,475, with the potential to avoid $1,079,293 in estimated damages. The project involved the installation of K-rails, sandbags, and traffic barricades and involved temporarily closing streets at two locations.
A third project, initiated November 18, consisted of three work items. These locations included north Sepulveda Avenue at 59th Street, where a canyon above a residential neighborhood had the potential for overflowing. The recommended work consisted of installing a rail-and-timber barrier to increase the capacity of a debris basin, and installation of K-rails and sandbags to prevent debris flows from entering several houses located along the west side of Sepulveda Avenue. The second work item consisted of K-rail and sandbag installations to redirect potential flows around residences located in the 300 block of West 59th Street. The third work item consisted of installation of a timber wall around a residence located at West 59th Street and Pershing Avenue. This house was located at the confluence of three canyons that had been burned. Due to some work done by the homeowner, this work item was revised to include installation of K-rail only. The cost for this work was $76,450 to avoid up to $654,694 in potential damage.
All work was completed by mid-December, and its effectiveness was soon tested. On December 25, 2003, a major storm with rainfall of up to 8 inches occurred within the city. In the county areas north of the city, 14 people were killed in Waterman Canyon when a debris and water flow swept over a church camp. In the Devore area at the northernmost tip of the city, a mudflow swept through a KOA campground, killing two people. The city of San Bernardino experienced significant erosion that resulted in streets filling with mud and debris, but in each location where NRCS erosion control measures were in place, damage was kept to a minimum. The work that was performed totaled $132,185 and prevented $2,415,000 worth of damage to the city.