Lessons from Hurricane Ike

Ch11: Land-Use Change and Increased Vulnerability

11 Introduction With over 50 percent of the US population residing in coastal areas, local decision makers are finding it increasinglydifficulttoprotectcriticalnatural resources, and facilitate the development of hazard-resilient communities. nowhere is this more apparent than on the texas coast. Rapid urban and suburban development has resulted in loss of critical habitats and key species while at the same time placing human populations in areas vulnerable to natural hazards. these problems are exacerbated within major population centers, particularly the houston /Galveston area, where population growth, sprawling development patterns , and the alteration of hydrological systems have created some of the most vulnerable communities in the nation. the following sections trace the causes and consequences of development within coastal watersheds with special emphasis on flooding in texas. the underlying premise is that human exposure to natural hazards, such as floods and hurricanes, is not solely a technical or engineering problem, but one driven by land-use change and the pattern of development across metropolitan regions. First, the causes of land-use change within coastal landscapes are addressed based on the following four factors: population growth, spread of impervious surfaces, loss of naturally occurring wetlands, and sprawling patterns of development . next, the adverse consequences of land-use change with respect to flood damage, social vulnerability, and risk exposure to severe storms are addressed . Finally, the policy and planning implications for mitigating the impact of the built environment and more effectively protecting communities from the threat of coastal hazards in the future are discussed. Background and Problem Statement Given the recreational, aesthetic, and economic opportunities available on the coast, this geographic area has historically been the focus for extenland -Use Change and increased Vulnerability Samuel David Brody Brody 139 sive population growth and land use change. in 2003 for example, it was estimatedthatapproximately153million people (53 percent of the population of the nation) live in the 673 US coastal counties, an increase of 33 million peoplesince1980 (Crossettetal.2004).As coastal population has increased, more structures have been placed in areas susceptible to the adverse impacts of the severe storms that routinely strike coastal areas. From 1999–2003 for example, 2.8 million building permits were issued for the construction of single -family housing units (43 percent of the total for the nation) and 1 million building permits were issued for the construction of multi-family housing units (51 percent of the total for the nation) within coastal counties across the United States (Crossett et al. 2004). Because communities positioned along a coastline or within a coastal watershed are especially vulnerable to surge, flooding, and high winds, this upward trajectory of growth has created the ideal conditions for human disasters (fig. 11.1). Figure 11.1. When hurricane ike struck, homes on 8th Street near Galveston were severely damaged. Photo courtesy Greg henshall/ FEMA. Land-Use Change and Increased Vulnerability 140 in particular, flooding and resulting flood damage within coastal areas has had a major impact on the national economy. Flooding is the most ubiquitous and costly natural hazard in the United States, causing billions of dollars in property damages each year. Using the national Weather Service (nWS) Storm Data publications, Mileti (1999) estimated property losses from floods to be from $19.6 billion to $196 billion between 1975 and 1994 alone. While damage estimates from floods vary, the economic costs from floods appear to be steadily increasing (Pielke and downton, 2000). For example , Birkland et al. (2003) reported flood damages from 1900–20 totaled $1.76 billion compared to $4.4 billion from 1980–2000. According to data extracted from the Spatial Hazard Events and Losses Database for the United States (ShEldUS), the average annual flood count has increased sixfold from 394 floods per year in the 1960s to 2444 flood events a year in the 1990s. ShEldUS data also show increasing property damage from floods over time. in the 1960s, floods caused $45.65 million dollars in damage per year; by the 1990s, average annual property damage from flooding increased to $19.13 billion dollars a year (inflation adjusted at 1960 dollars ) (Brody et al. 2007a). these damage estimates help confirm what has been understood by local decisionmakers for over a decade: that floods and severe storms are a major risk to the health and safety of the US population and with increasing development in low-lying coastal areas, the problem appears to be getting worse. hurricane ike illustrates the negative impacts...