Document Type

Article

Publication Date

Spring 2024

Abstract

While sea level rise has long received a great deal of attention, another impact of climate change is now getting greater notice — increases in extreme precipitation. As the atmosphere warms, it can hold more moisture; for every increase of one degree Celsius, seven percent more water vapor is carried in the air. When that moisture is quickly released as intense rainstorms, stormwater systems can be overwhelmed, and cities can suffer devastating floods.

The frequency and intensity of heavy precipitation events have increased since the 1950s over most of the world's land areas. One 2023 study — generally consistent with several prior works — projected a 51.6% increase in extreme precipitation in the northeastern United States by the end of the 21st Century. What have historically been called 100-year storms (indicating that a storm of that magnitude has a one-in-one-hundred chance of occurring in a given year) are now occurring as often as every five or ten years. In one five-week period in 2022, places in several different parts of the U.S. (St. Louis, eastern Kentucky, eastern Illinois, Death Valley, California, and Dallas-Fort Worth) were all struck by what were called 1,000-year rain events — storms with a one-in-one-thousand chance of occurring in a given year. On top of extreme rainfall, storm surge worsened by sea level rise can devastate coastal cities, but even inland locations that are near — or not so near — rivers can see similar destruction. In addition to the disruption of property, many illnesses can result when stormwater causes the release of untreated sewage onto the surface of, and into, waterways. Ecological impacts, such as increased fish mortality caused by the polluting runoff, also occur.

There is ample literature on flooding caused by sea level rise. The focus of this article, however, is on flooding in cities caused primarily by rain combined with land-use patterns and inadequate stormwater drainage. Though, of course, the two often combine.

This article proceeds as follows. Part I discusses the nature of the growing crisis in urban flooding, how precipitation is estimated, and how expected flooding is (or is not) disclosed in maps and otherwise. Part II shows the roles of the different levels of government — federal, state, and local — in addressing urban flooding. Part III goes through the various physical methods of coping with urban flooding (grey infrastructure, infiltration, storage, defense, accommodation, and retreat), and some of the associated legal implications. Part IV concerns how the physical methods discussed in Part III can be financed. Part V concludes with thoughts on setting priorities.

Disciplines

Climate | Disaster Law | Environmental Law | Law

Comments

Copyright © 2024 Journal of Land Use & Environmental Law.

Center/Program

Sabin Center for Climate Change Law

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