Lessons from Hurricane Ike

Ch10: Hurricane Impacts on Critical Infrastructures

Introduction hurricanes have far-reaching impacts at numerous levels on the natural and built landscape. the effects are felt for years and the recovery process can be long and slow depending on the nature of the event. this chapter focuses on the impacts of hurricanes on critical infrastructure along the texas Gulf Coast,specificallyontheimpactofhurricane ike on the houston/Galveston area. Critical infrastructure is defined in this chapter in the broadest sense to include the built landscape, municipal infrastructure, environment, natural resources, industry (including ports and shipping), power and transportation networks, and public and private services. in addition to describing damage from ike, this chapter provides some insight into potential damage to the municipal and petrochemical sectors in the event of a larger storm. hurricane ike affected the regional infrastructure to varying degrees. ike caused catastrophic damages to Galveston and coastal resources in texas, but further inland, the most severe effects were loss of power due to toppled power poles and lines and damage on residential, commercial, and industrial structures caused by fallen trees. Some of the effects of the storm were secondary impacts due to primary effects on another element. For example, the integrity of water distribution network was lost due to loss of power. Fewer damages were incurred from flooding when compared to surge and high winds. Built Landscape Urban built landscapes are sophisticated and complex systems. they include commercial and residential built space with interconnected municipal services such as water, sewer, power, stormwater,telecommunications,fuel, and solid waste facilities. hurricanes have multi-faceted effects on this infrastructure ranging from destruction to disruption of services or damage to specific components. in general, there are three types of possible damages: wind damage, storm surge damage, hurricane impacts on Critical infrastructures Hanadi S. Rifai 10 Rifai 123 and flood damage. Wind damage can destroy poorly constructed buildings and send debris such as roofing materials , signs, and siding flying. Storm surge is capable of removing a home from its foundation and completely destroying relatively weak structures. Floodwater and surge can inundate structures causing water damage and conditions suitable for the development of mold. Vehicles left in residential neighborhoods are typically submerged and destroyed. Commercial infrastructure includes stores, buildings, and commercial strip centers, whereas service infrastructure includes schools, public buildings, power transmission networks , and gas stations, among others. hurricanes significantly impact this sector, through physical destruction and damage as well as by interrupting services. For example, in schools in Galveston, classrooms and common facilities were destroyed by high winds and water damage. thousands of children were unable to return to school because class was canceled for almost a month while facilities were repaired. during hurricane ike, thousands of homes along the upper texas Gulf Coast were severely damaged (fig. 10.1). Bridge City and Gilchrist are two communities that were hard hit by ike and had all but 15 homes within their residential neighborhoods completely destroyed (FEMA 2008). Waterfront cities between Galveston and houston sustained residential infrastructure damage (e.g., dickinson, Kemah, league City, and Clear lake Shores in Galveston County, and El lago, la Porte, nassau Bay, and Seabrook in harris County), but more importantly, had substantial losses in their sub-regional economies which rely on tourism , water recreation, nASA, and the houston Ship Channel industry. table 10.1 displays the real estate losses by dollar amount of damage after ike. Upwards of 3300 units were destroyed and more than 100,000 units experienced damage amounting to more than $25,000 per unit. Power Loss hurricane winds and storm surge can damage power networks and cause power outages to significant areas. Power grids are fragile systems with centralizedcontrolandnoredundancy in sub-transmission and distribution paths. Power outages are associated with numerous secondary effects that may be more costly than the primary loss of power. they plunge areas into darkness and idle pumping stations, cutting off water supplies and allowing wastewater release. during ike, more than 2 million residents of the greater houston area lost power (fig. 10.2) and it took 19 days for normal service Hurricane Impacts on Critical Infrastructures 124 to return to most residents. Power outages in the houston area were primarily caused by downed trees and power lines due to high winds (110 mph). in Galveston, storm surge flooded four of the power substations. thus, the majority of the damage was in the distribution network, rather than in transmission and substation power infrastructure. there have been proposals...