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|Federal Highway Administration > Publications > Public Roads > Vol. 62· No. 1 > Planning for a New Type of Natural Disaster: El Niño Phenomenon Brings Innovative Approaches|
Planning for a New Type of Natural Disaster: El Niño Phenomenon Brings Innovative Approaches
by John Cagle and Arlo Waddoups
"To be, or not to be; that is the question."
Hamlet's classic query was on the minds of the Federal Highway Administration's (FHWA) Region Nine staff last fall. Would the much-publicized El Niño actually bring widespread flooding and mudslides to their region, which encompasses Arizona, California, Hawaii, and Nevada? Was it "to be"?
Scientists had been warning that the unusually high sea-surface temperatures in the Pacific could portend disaster. And while the El Niño phenomenon is not new - Spanish-speaking South Americans named it years ago for the birth of the Christ child celebrated during late December, when El Niño manifests itself - this particular El Niño was foreseen as having the potential to be particularly troublesome.
After several weeks of such warnings, however, no heavy rainstorms had hit. Skepticism began to set in, followed by sarcasm. Advertisers used El Niño as the punch line for their commercials, making serious consideration of the phenomenon unfashionable. Even the editorial copy in newspapers began to poke fun. One headline said, "Having a bad hair day? Blame it on El Niño." Stand-up comedians found a new source of material. The Los Angeles Times quoted one comic, Willy Parsons, as having joked, "If this El Niño gets much worse, I'm going to have to get a stronger sun block."
Because El Niño was such an unknown concept to most Americans, they didn't know how seriously to take the dire predictions they were hearing. And, as an October conference on how to prepare for El Niño met in Los Angeles, federal, state, and local government officials attempted to put together plans for an emergency the likes of which few of them had ever faced.
Disaster preparedness is nothing new for transportation professionals. They're used to planning and designing for such events as earthquakes, floods, and hurricanes. These preparations generally come in two forms: "Reactive" preparations, such as moving people out of harm's way as a storm approaches, are short term, and the danger is imminent. "Proactive" preparations anticipate natural disasters, such as earthquakes or 100-year-frequency floods, years or decades before they hit and design facilities to withstand them.
El Niño was a little of both. The impact was looming, but there was no visible evidence of it - no storm clouds on the horizon. Also, particular geographic areas that have historical records for natural disasters acquire specialized expertise that evolves over time. Roadways or bridges in Miami or San Francisco, for example, can be designed with hurricane winds and earthquake tremors, respectively, in mind, based on data gained from numerous impacts from such forces. Similar facilities in northern Minnesota might be built to withstand the problems that come with extreme cold. But with El Niño of 1997-98, there was relatively little in the way of a state-of-the-practice in planning and design.
A New Way of Thinking About Disaster Preparedness
The California Division Office of FHWA conducted training sessions on how to apply for emergency relief funds. The state's Local Technical Assistance Program (LTAP) Center did the same with city and county agencies. Getting agency people conversant with the requirements for applying for funds prior to any disaster would mean hours saved after the storms hit. And, of course, those minutes and hours are much more precious when inundated roadways need to be cleared.
In addition to preparing for procedural challenges, FHWA wanted to anticipate the physical impact on the highway system. The two key areas were flooding and landslides. The magnitude of each would be determined by the duration and intensity of the precipitation. Flooding would be the major problem if the El Niño-spawned weather consisted of heavy rains over a short period of time. If, on the other hand, the rains came slowly and constantly, saturating the soil until it could no longer remain stable, landslides would be the problem. So how would this affect the highway system?
For landslides, sites that historically have been prone to slides were identified and monitored. Should these areas begin to slide, roadways would need to be blocked off to minimize loss of life and property. In the case of heavy flooding, one of the major problems is bridge scour. This phenomenon occurs when the fast-moving subsurface currents of a stream churn up and erode the soil around the supports of a bridge. Ultimately, scour can cause bridges to fail, and the cost in lives, disruption of travel, and dollars can be staggering.
For example, on March 10, 1995, near Coalinga, Calif., twin bridges carrying Interstate 5 over the Arroyo Pasajero collapsed, killing seven people. Reconstructing the bridge cost almost $6 million, plus an estimated $550,000 per day in lost travel time and higher fuel use to the public for eight days until an innovative temporary bridge was put into place. (See "California's Temporary Freeway Bridge" in Public Roads, Autumn 1995, pages 2 and 3.)
With the magnitude of possible flooding, El Niño had the potential to cause scour at virtually all of the 21,703 water-spanning public bridges in Region Nine.
To make sure that state departments of transportation understood the potential for disaster, we arranged for five classes on bridge scour to be taught to field personnel in Arizona, California, and Nevada. The sessions were designed to help the staff understand and recognize scour problems at highway bridges as the problems were occurring. The classes were provided at no cost to the states through the National Highway Institute. Also, a "Test and Evaluation Project for Pre-Emergency Scour Countermeasures" was implemented. The project permitted the use of simplified and expedited procedures to get projects cleared for construction. It also made Highway and Bridge Rehabilitation and Replacement Program (HBRRP) funds available for projects that were not previously eligible. Under the program, approximately $13 million in improvements are underway through the state transportation agencies in Arizona, California, and Nevada. Some 35 local agencies throughout the region are also taking advantage of the program. This was not "new money" specifically allocated for El Niño, but rather a shift in priority by the states after encouragement from the FHWA division offices in those states.
In addition, physical systems to monitor scour depth and provide a warning signal are being set up at bridges throughout the region. The equipment notifies the bridge owner when scour reaches a predetermined level. It sends this information telephonically over telephone lines, cell phone systems, or satellite systems. Initially, 15 such bridges were equipped with the permanent devices, with more being outfitted by state and local staff. Two portable devices were provided to Arizona and Nevada for monitoring scour depth on any bridge they choose to look at before, during, or after the high flows. All of the equipment was offered to the states at no cost under FHWA's Demonstration Project 97, "Scour Monitoring and Instrumentation." This project had been ongoing and had developed methods and equipment for measuring scour depths during flow events.
With the threat of El Niño, close coordination between the regional office and the Office of Technical Applications (OTA) in Washington, D.C., resulted in a special dispensation of funds to rapidly implement these procedures on some of the most at-risk bridges in each state. Purchase orders were issued directly out of the regional office for both consultant design services and direct acquisition of the equipment. The state departments of transportation agreed to install the equipment with state resources.
While El Niño's effect was felt throughout Region Nine, it hit California particularly hard - and perhaps the San Francisco Bay area hardest of all. At various times throughout the region, there were sink holes, landslides, flooded highways, and roads blocked by fallen trees and other debris. By April, the California Department of Transportation (Caltrans) was estimating road damage in the Bay Area alone at well over $50 million. Statewide, the agency set overall damage to the highway system at around $300 million.
Of all the highways, state Route 1, the Pacific Coast Highway, got the biggest hit. The portion that runs through the popular Big Sur area was closed for 13 weeks. Forty sections in the 115-kilometer stretch from Carmel to San Simeon were damaged by El Niño-created washouts and landslides. Farther north and closer to San Francisco, at the coastal community of Pacifica, another section of Highway 1 was closed when an eight-meter-deep, nine-meter-wide mass of soil poured onto the highway. It took two days to haul away almost 7,500 cubic meters of material. And still farther north, across the Golden Gate Bridge, another slide dropped a 30-meter section of the same highway into the Pacific Ocean. Roadways throughout the Bay Area had similar problems. Highway 84 in Woodside was hit by four different slides, while tons of dirt poured onto a major roadway in the community of Portola Valley, eight kilometers to the south.
Potholes were a headache everywhere. With the constant rain, some potholes grew to enormous size. One, near Altamont Pass, outside of Livermore, grew to a three-meter-by-three-meter crater. Another giant sinkhole appeared in the middle of Interstate 680 near Pleasanton, and a car-eating pit opened up within the city of San Francisco itself. That city typically fills about 40 potholes a week. During the week of Feb. 16, according to the San Francisco Examiner, city crews filled potholes in 157 locations. Statewide, by early March, Caltrans maintenance crews had logged more than 116,000 man-hours filling thousands of potholes.
Coastal area highways weren't alone in feeling El Niño's wrath. More than 160 kilometers inland, in the central part of the state, some 80 kilometers of state Highway 99 between Bakersfield and Visalia were shut down for a week because of the flash flooding of two normally dry creeks. Entire towns were flooded, and three underpasses for Highway 99 were virtual lakes.
In all, 42 of the 58 counties in California were declared disaster areas, and February 1998 was the wettest February ever for some areas of the state. California is estimating $500 million in damage to public facilities, and FHWA is working with Caltrans to evaluate the extent of the damage to the state's highway system.
This process has already been implemented for the issuance of two permits for a local government agency and will have major positive effects as Arizona continues with its countermeasure program. For example, these permits from the Corps of Engineers grant the states environmental clearances and other approvals necessary to proceed in constructing physical countermeasures on bridges to prevent failure during high flows. These include articulating mattresses that are placed on the channel bottom around the bridge supports to prevent scour from occurring.
And the system worked. A U.S. Highway 101 bridge near Salinas was fitted with a warning device to signal Caltrans when the scour had reached two levels so they could keep its progress under surveillance. The signal went off at the first level, but it never reached the level at which the bridge would have to be shut down.
While much was done to prepare bridges, the most costly roadway damage came from landslides, particularly along the coast. According to a recent study by the Institute of Marine Sciences at the University of California at Santa Cruz, 86 percent of the state's 1,800-kilometer-long coastline is crumbling, and coastal erosion makes the state, on average, 150 to 300 millimeters skinnier every year. Questions about the use of such anti-erosion tools as seawalls and riprap are being debated by land planners, developers, environmentalists, and government officials. As long as highways are built along such geologically active areas as the California coastline, it will be difficult to eliminate problems from landslides. So, while researchers will continue to seek solutions to landslides onto roadways, policy makers will need to evaluate the appropriateness of highways in such locales.
History shows that natural emergencies are not all that unusual in California, which caught the brunt of the El Niño storms. Over the past eight years, the state has averaged slightly more than one major natural disaster each year - primarily floods and earthquakes - and several of these cost more than $100 million to restore the highway system. The big difference with the El Niño storms is that they were predicted. For the first time, workers had months to prepare for coming storms - time for maintenance staffs to stockpile the necessary repair materials in strategic locales and time to get familiar with the procedures necessary to apply for funds after the storms were over.
The old, inexact ways of predicting weather have given way to high-tech methods using satellite monitoring and other new tools. The 1997-98 El Niño showed that the benefits provided by these new, more reliable prediction methods can be lost if government doesn't take a new look its procedures and processes for predictable disasters. The efforts in Region Nine were a start in that effort.
John Cagle is the marketing specialist for FHWA's Region Nine. His 22-year career in transportation marketing includes work at consulting engineering firms, the Texas Department of Transportation, and the Texas Railroad Commission, where he worked on the state's alternative fuels program. He has a bachelor's degree in journalism from the University of Texas at Austin and has been accredited in public relations by the Public Relations Society of America.
Arlo Waddoups is the hydraulics engineer for FHWA's Region Nine. His 19 years with FHWA has included hydraulic design for roadway facilities, work with the hydraulics engineers in state departments of transportation, and the teaching of more than 65 courses nationwide for state and local hydraulics engineers. He also worked in the private sector, attaining the level of executive vice president of a consulting engineering firm with some 70 staffers. Waddoups received both his bachelor's and master's degrees in civil engineering from Utah State University, and he is a registered professional engineer in Arizona, Idaho, Illinois, Nevada, and Utah.
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