Recent Earthquakes: Implications for U.S. Water Utilities [Project #4408]

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1 Recent Earthquakes: Implications for U.S. Water Utilities [Project #4408] ORDER NUMBER: 4408 DATE AVAILABLE: July 2012 PRINCIPAL INVESTIGATORS: John Eidinger and Craig A. Davis PROJECT PURPOSE: The purpose of this project is to provide water agencies information that highlights the following: Damage to water system infrastructure in three recent earthquakes (Chile 2010, Christchurch , Japan 2011). Response of the water agencies in repair and restoration of potable water service to customers. Effectiveness of various earthquake-countermeasures that were previously implemented by these water agencies. This includes upgrades of tanks, buildings, equipment, and (selectively) replacement of old buried pipe with "earthquake-proof" pipe. In order to understand: The factors causing water system service outages. The strategies used and their effectiveness to restore water systems. Water system restoration times. The damaged infrastructure includes: Buried water pipes (PVC, Cast Iron, Asbestos Cement, welded steel, HDPE, etc.) This includes both distribution pipes (commonly 6" to 12" diameter), transmission pipes (commonly 24" to 96" or larger in diameter), and service laterals (commonly under 2" diameter) Water tanks. These include at-grade welded steel circular tanks, at-grade reinforced concrete and prestressed concrete circular tanks, and below grade reinforced concrete tanks. Wells. Water Treatment Plants/Pump Station Facilities. The damage is addressed with regards to the various seismic hazards: Ground shaking Ground failure due to liquefaction

2 Landslide Surface faulting Inundation (flooding) due to tsunami Based on the observations from these recent earthquakes, this report provides guidance for the effectiveness of possible U.S. water system improvements that are cost-effective to address the following: Pipe replacement to address seismic weaknesses as well as pipe aging (leaks, corrosion, etc.) Water tank upgrades for seismic weaknesses Well head seismic upgrades Emergency Response preparedness and implementation (manpower, training, equipment, mapping, communication with the public) APPROACH: To develop this report, the following approach was taken: The principal investigators for this project visited with the water utilities in the affected countries: Mr. Eidinger visited Chile (April 2011), Christchurch (October 2010, April 2011, August 2011, December 2011), Japan (June 2010, October 2011, February 2012). Dr. Davis visited Christchurch (April 2011), Japan (July 2011, October 2011). Some of these visits were sponsored by the Water Research Foundation, and others by the American Society of Civil Engineers (ASCE), Technical Council on Lifeline Earthquake Engineering (TCLEE), and others separately. The researchers interviewed and collected information from the affected water utilities, and visited many of the sites with damaged water infrastructure. Some of the damage information presented in this report is based on tabulations developed by the affected water utilities. The researchers followed up with some of the water utilities to obtain additional maps, GIS information, reports, etc. SUMMARY FINDINGS: This report addresses the damage to water systems in three countries due to recent earthquakes in 2010 and Table 1-1 highlights damage categories in each earthquake.

3 Table 1-1. Summary of Damage (N.A. = not applicable. Unk. = unknown) Asset Category Chile Christchurch Japan Damage to large diameter transmission pipes Many n.a. Many Damage to small diameter distribution pipes Thousands Thousands Thousands and service laterals (CI, AC, PVC, etc.) Damage to HDPE distribution pipe None None None Damage to Kubota chain-jointed ductile iron N.A. N.A. None pipe Damage to at-grade wood, steel or pre-stressed Minor Many Few concrete water storage tanks due to shaking Damage to at-grade concrete water tanks due to None Yes None ground failures Damage to seismically-designed buried steel N.A. N.A. Yes tanks due to liquefaction Damage to water treatment plants Yes N.A. Yes Damage to pump stations Unk. Yes Unk. Damage to wells Not known to have occurred Widespread in liquefaction zones Damage to elevated steel tanks Widespread N.A. N.A. Fire ignitions due to earthquake 2 ~ 10 ~ 124 Fire ignitions due to tsunami None N.A. ~ 167 Suspected due to salt water intrusion, but not verified The key findings are as follows: Chile Earthquake This subduction zone earthquake seriously impacted the City of Concepcion, with a population over 1,300,000 people. The water system in this city had not been designed for earthquakes. Strong ground shaking and liquefaction damaged the city's only water treatment plant. Liquefaction damaged many of the larger diameter steel transmission pipelines. Liquefaction damaged many distribution water pipelines (about 3,000 total). Water outages to customers were lengthy, over a month to some customers. Even so, there was some good news: Essbio (the water system operator) had been installing HDPE pipe in its water distribution system for about a decade prior to the earthquake; while the rest of the water system suffered thousands of damaged pipes, no HDPE pipe was damaged. This earthquake also shook a wide area of Chile, much of it rural/farming. Over the prior decade, the central government of Chile had installed 2,000 small wells water tank systems for these small farming communities (typical population of 100 people or fewer). A standardized type elevated steel tank design was used throughout the country.

4 Unfortunately, the design was insufficient for strong ground shaking, and at least 73 of these elevated steel tanks collapsed, sometimes causing fatalities. The restoration of water service after the earthquake was seriously slowed down by the failure of the regional power supply and communication networks (cell phones). The water companies had learned to use cell phones as their primary method for voice communication. Primarily because of the failure of the widespread cell phone system, restoration efforts were delayed by a few days. There were two fire ignitions requiring fire department response after the earthquake; there was no fire spread. The damage to the water system had no impact on the outcomes of these fires. Christchurch Earthquakes A series of three crustal earthquakes hit Christchurch in September 2010, February 2011, and June The earthquake affected an urban population of about 400,000 people. Each earthquake damaged the water system. Between the three earthquakes, many thousands of repairs to water pipe mains and sub-mains were required. The water pipes and wells in this city had not been designed for earthquakes; a few of the potable water tanks had been seismically upgraded prior to the earthquakes. Strong ground shaking and liquefaction damaged many of the city's wells. Liquefaction damaged many distribution water pipelines. Some of the water tanks performed well (some rooflevel damage still occurred), a few very small unanchored wood and steel tanks slid, and several larger pre-stressed concrete tanks had serious damage (ongoing leaks) or failed completely (lost all water contents). The city's largest concrete reservoir failed completely due to ground deformations. Water outage durations to customers were moderate, mostly restored within 10 days after each earthquake. Even so, there were some good lessons learned: The Christchurch City Council (the water system operator) had installed some HDPE pipe in its water distribution system after the first earthquake; in the subsequent earthquakes, no HDPE pipe was damaged, while nearby older pipes were damaged. There were a few fire ignitions requiring fire department response after the first and second earthquakes; there was no fire spread. The damage to the water system had no impact on the outcomes of these fires. Tohoku Earthquake A magnitude 9 earthquake hit the northeastern part of Japan on March 11, 2011, commonly called the Tohoku region of Japan. The earthquake affected an urban and rural population of about 35,000,000 people. The largest city close to the epicentral area is Sendai, with greater metropolitan population of about 1,500,000 people. The great magnitude of the earthquake also resulted in some earthquake damage to water systems in more distance large prefectures, including Chiba, Tokyo, Kanagawa, and others.

5 The earthquake also triggered a major tsunami event. The tsunami event caused the vast majority (likely over 95%) of all damage and fatalities in Japan, affecting just the first few hundred meters (distances vary along the coastline) inland from the shore. Just outside the tsunami inundation zone, damage to the regular building stock was nearly zero. The tsunami seriously damaged many wastewater treatment plants located at the low elevations near the coastline. The tsunami event had nearly zero impact on potable water systems outside the inundation area. In part due to the many large earthquakes in Japan's history over the past 100 years or so, and in particular the 1923 Great Kanto earthquake (affecting Tokyo) and the 1995 Great Hanshin earthquake (affecting Kobe), many (not all) of the larger water utilities in Japan have undertaken extensive (and expensive) seismic countermeasures over the past 20 years or so. These countermeasures include seismic upgrade of tanks and water treatment plant buildings/facilities; installation of underground emergency storage tanks; and most importantly (and most expensively), wholesale replacement of older (more than 50+ years old) pipelines with new "seismic resistant" water pipes, mostly ductile iron with chained joints (as manufactured by Kubota) and electro-fusion welded HDPE. Two water treatment plants suffered major damage due to liquefaction. A large diameter water transmission pipeline in the epicentral area suffered major damage at more than 50 locations, mostly due to pulled slip joints. A few large diameter water transmission pipelines suffered some slip joint damage in low-shaken areas, very distant from the earthquake. There was no known major damage to at-grade water tanks. Below-grade emergency storage tanks, installed for purposes of providing potable drinking water to local residents, in the event of damaged pipeline distribution networks, mostly performed well (undamaged), but one performed poorly (liquefaction damage). It seems that in areas where the emergency buried tanks performed well had no other major damage, so they were mostly unneeded; in one area where the emergency buried tank performed poorly, there was also a lot of damage to the buried pipeline network and water outages were widespread and lengthy in duration. At the time of the earthquake in March 2011, between 5% to 15% (some water utilities have higher percentages of seismic-resistant pipe, others have none) of the water pipelines in the strong-shaken area had been upgraded with seismic-resistant pipe. By "seismic resistant pipe", it is meant pipe that can sustain a modest amount of ground deformation without failure. In Japan, the most common types of ground failures are due to liquefaction or landslide; given the nature of the earthquake hazard in Japan, fault offset is not generally a concern (and there was none in the March 2011 earthquake). None of the seismic-resistant pipelines is known to have been damaged in the March 2011 earthquake. The observed good performance of the seismic-resistant pipe cannot be extended to say it would perform equally as well under highly concentrated ground deformations due to fault offset.

6 As of the time of writing this report (mid-2012), the tabulated count of fire ignitions is 315, of which 124 were caused due to the tsunami; 167 due to ground shaking; and 24 due to uncertain cause. In one coastal town impacted by the tsunami, some initial ignitions spread and burned several neighborhoods. In all but one instance, the selfevacuation of people from the low lying area resulted in apparently no fire department response to any of the tsunami-caused fires. RECOMMENDATIONS FOR U.S. WATER UTILITIES: Over the past 20 years or so, many U.S. water utilities in high seismic regions have adopted seismic retrofit practices for buildings, water treatment plans, and tanks. The lessons learned in these three earthquakes confirm that these practices remain sound practice. Even so, a major weakness remains for nearly all U.S. water agencies in high seismic zones, namely that the existing buried pipe infrastructure remains highly susceptible to damage due to earthquake-caused ground failures (liquefaction, landslide, surface faulting, and other effects). Today, most U.S. water utilities continue to install nonseismically-designed distribution pipes, even in zones prone to ground failure effects. A few U.S. utilities have seismically retrofitted (or replaced) the most critical large diameter transmission pipes across known active earthquake faults, mostly using welded steel pipe, and in a few cases, HDPE pipe. These three recent earthquakes continue to show that the bulk of the total earthquake damage to water systems, and the resulting water outages to customers, is due to failure of hundreds to thousands of smaller diameter distribution pipes in zones of infirm ground. Until water utilities install seismically-resistant pipes in these areas, this problem will continue to re-occur in future earthquakes in the United States. New technology in water pipeline joinery has been in place in Japan for nearly 20 years, and today (2012), it is estimated that more than 75% of new water pipes installed in Japan use seismic-resistant design; in California, less than 1% of new water pipes use seismic resistant design. For common distribution pipes and service laterals (from under 1" to 8" diameter), HDPE pipe (either fusion butt welded or electro-welded with clamped joints) appear to have excellent earthquake performance, as evidenced in all three recent earthquakes. For distribution and transmission pipes (from 3" to greater than 100" diameter), ductile iron pipe with "chained" joints, as manufactured by Kubota of Japan, have had excellent performance in the March 2011 and many other Japanese earthquakes. Several areas for further applied research by the Water Research Foundation are recommended: Develop a cost effective pipe replacement strategy for U.S. water utilities that factors in the ongoing issues of aging pipeline replacements, as well as earthquakes. A seismic design guideline for water pipes (ALA 2005) is currently available in the United States, but it addresses only seismic issues. This guideline, coupled with addition issues for pipe aging/corrosion, plus the ongoing lessons learned, should be updated for practical implementation by U.S. water utilities.

7 Research into the failure of larger diameter water transmission pipelines at slip joint locations. While ALA (2005) provides some guidance, the failed large diameter pipe observations in Japan as well as other earthquakes shows that the current mandatory design standards (such as AWWA M11 and others) are completely lacking in requirements for seismically-designed slip joints (or bellows or similar). As part of this research, a better understanding of the multiple failures of large diameter girthwelded steel pipes in liquefaction zones in Concepcion should be done to reveal the root causes of these failures. Review and update the Performance Goal targets that are suitable for U.S. water utilities. As of 2012, different water utilities have adopted widely varying goals (ranging from bulk water restoration in 1 day to as much as 30 days or longer after major earthquakes), resulting in widely varying earthquake preparedness and mitigation strategies, and capital costs. Nothing the researchers observed suggests that Performance Goals should be legal mandates. Even so, if a water utility adopts overly aggressive Performance Goals, the resulting cost impacts to ratepayers may seriously outweigh the future benefits. With these considerations in mind, a review of the various strategies recently adopted, addressing forecast benefits, and actual costs, would be a useful document to utilities to help them select their own utility-specific strategies. Review and update the available fire following ignition models in ASCE (2005). These models are also used by FEMA in HAZUS. In all three earthquakes, the evidence appears to clearly indicate that the older models (ASCE, HAZUS) overpredict the number of earthquake-caused fire ignitions in modern cities (Concepcion, Christchurch, Sendai, etc.). This may be in part due to the over-weight (ASCE, HAZUS) of fire ignition data from the 1906 San Francisco earthquake, the 1933 Long Beach earthquake, and other earthquakes where the widespread collapse of unreinforced masonry buildings occurred; the use of modern electrical wiring; and other factors. While fire ignitions are still occurring, they seem to be occurring at a much lower rate (perhaps a 75% reduction) from that older earthquakes, like the 1906 San Francisco earthquake. If true, then the lower fire ignition rate would somewhat lower (but certainly not eliminate) the need to seismically mitigate existing water systems. Review and update AWWA and other standards for steel and pre-stressed at-grade concrete tanks to reflect ongoing poor performance of these tanks when exposed to high levels of ground shaking. The unanchored steel tank provisions should be carefully reviewed, especially for smaller steel tanks in high seismic hazard areas (PGA 0.3g or higher). The combination of vertical earthquake and hydrostatic forces for prestressed concrete tanks needs to be reviewed to ensure that yielding of hoopdirection prestress steel does not occur under high levels of ground shaking. The acceptable ductility limits in current ASCE 7, IBC, ACI, and AWWA codes (ranging from 2 to 4.5 or so) need to be reviewed and revised as suitable in order to provide suitable reliability for a leak-tight tank under high levels of ground shaking.

8 ADDITIONAL INFORMATION: This report was written and edited between late 2011 to mid Over the next decade or so, additional research into specific aspects of the water system performance will be developed. The interested reader should be aware that there are three organizations in the United States that also have done reconnaissance into the effects of these three earthquakes: ASCE TCLEE sent out a number of investigation teams to Chile, New Zealand, and Japan to document the performance of all types of lifelines, including water, power, communications, gas and liquid fuels, ports and harbors, railroads, highways, debris management, wastewater, etc. The authors of this report participated as part of those teams. ASCE TCLEE plans to publish comprehensive reports on each earthquake, including detailed discussions on the earthquake performance of water systems. ASCE reports are available from GEER Association (Geotechnical Extreme Events Reconnaissance) teams have developed reports on the seismic hazards portion of these earthquakes. GEER reports on all three earthquakes are available from EERI (Earthquake Engineering Research Institute) teams are developing reports on performance of structures and societal response on all three earthquakes. A special issue dedicated to the Chile 2010 earthquake, to be published in 2012, will include a detailed discussion of the performance of the earthquake performance of the water systems. EERI reports on all three earthquakes are available from The interested reader should also be aware that some additional information from three case studies of earthquake impacts to water systems is also available. These case studies cover the experience in recent earthquakes in Chile, New Zealand (Christchurch), and Japan (Tohuko earthquake), and are available to Water Research Foundation subscribers, for information purposes only, upon request to the Water Research Foundation.