Overdevelopment and Flooding

by Mary Beth Radeck
(December 2011)

160 years ago, lowlands and floodplains were as common in Schaumburg and the Salt Creek Watershed as shopping malls are today. Most of the naturally flat prairies and wetlands in this area were first drained and converted to farm fields, then later improved to support business and new residences. As of 2004, 92% of Schaumburg had been developed, according to Applied Ecological Services (2004, p iii). This nearly complete coverage of land has interrupted the natural flow of water from Schaumburg through the watershed.

1851 map of Schaumburg’s natural surface water resources (source: Encyclopedia of Chicago)

Konrad (2005) statea that “urbanization generally increases the size and frequency of floods” and concluded that development around Salt Creek boosted flood peak flow volumes by 100% to 200% in the last half of the 20th century (p. 5). Today, Schaumburg relinquishes more storm water to the watershed than is saved. The preponderance of roads, parking lots and even turf grass jettisons massive volumes of rain water which continue to overwhelm man-made sewers, sending what could be water secured in deep aquifers downstream instead, to the Mississippi and eventually the Gulf of Mexico.

Flooding Endangers People and Damages Property

In addition to the loss of precious water, the speed, volume and velocity of stormwater create floods that threaten humans. Flash floods can deliver a wall of water more than 10 feet high which can quickly overwhelm structures within the built environment. Flash floods frequently occur at night (National Flood Insurance Program [NFIP], 2011).  Almost half of all flood fatalities occur in vehicles and underpasses which are especially treacherous (National Oceanic and Atmospheric Administration [NOAA], 2011. p. 3).

Aerial view of Schaumburg today (source: USGS satellite image)

A car can float away in just two feet of water (NFIP, 2011). Danger lessens after the flood but doesn’t evaporate with flood waters. Solomon (2006) reports that mold concentrations double after a flood, which causes asthmatic reactions in sensitive individuals and can cause allergic reactions, too (p.1). The health risks from flooding escalate near rivers and streams in low-lying areas downstream from Schaumburg, since Schaumburg resides on higher ground than the rest of its watershed communities.

Flooding not only risks health, but can be financially devastating, too. Damage from just one inch of flood water in a home can be costly. Nationally, over the last ten years, flood losses exceeded $2.7 billion per year (NFIP, 2011). Flooding is a chronic issue which appears to have worsened as development advanced. Over a two-year time span in the 1980s, Lake and Cook Counties in Illinois experienced uncontrolled flooding that, according to Krohe (2011), caused more than $100 million in severe damages (p. 1). This appeared to be a fluke until 20 years later when statistics revealed by the Upper Des Plaines River Ecosystem Partnership (2011) stated that flooding had caused over $40 million annually in flood damages in six northeastern Illinois counties alone (p. 24). Now, according to NFIP, “everyone lives in a flood zone.” Still, most homeowner’s insurance does not include flood damage even though one-third of flood disaster assistance is paid to individuals who live outside of high-risk areas.

Flooding Causes Ecosystem Degradation

Not only does flooding threaten people and property, it also causes heavy losses to ecosystems if unmitigated. Zhou and Wang (2007) states that as little as 10% impervious coverage cause stream quality to suffer (p.1).

Des Plaines River flooding near Wadsworth, IL (Source: Sara Mikel)

Increases in water volume to streams in an urbanized environment creates a destructive rush of runoff from impervious surfaces though storm sewers to streams. The blast carries many types of pollutants ranging from petroleum products to salt and fertilizer. It scours stream banks, dislodges plants, and clouds the stream which in turn reduces plant life, the building blocks for the food chain, “wip[es] out habitat” (EPA, 2003). Pollutants destroy habitat with algae blooms which devour the oxygen in the water, making it barely livable for fish. As oxygen is depleted and food for small organisms is less plentiful, animals higher on chain disappear. Biodiversity is severely affected by water quality degradation.

Next page: Pollution in the Watershed

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