Impervious surfaces. These are two words that most folks in their lifetime will never utter together, unless, of course, you happen to live in an urban flood plain.
A little over 160 homeowners who live adjacent to Cameron Run in Fairfax, Virginia have become quite familiar with the concepts of imperviousness, and what it means when a significant rain event occurs. Within the last five years, these homeowners have seen their homes repeatedly inundated by the floodwaters of Cameron Run, events that in the past would have been classified as “100- year floods.”
The Cameron Run watershed, within a stone’s throw of downtown Washington, D.C., was once comprised of forest, meadows and farms. Seventy years ago a development of modest, single-family homes were constructed in the Huntington Community. At the time, Cameron Run was a mostly bucolic stream that had a history of being a navigable waterway, and home to one of Alexandria’s largest mills. The first building boom to affect the waterway actually happened shortly after the Civil War, at which time sedimentation slowly made Cameron Run non-navigable. The mills closed and much of the adjacent lands were transformed into rail yards and industrial complexes.
Around 1940, when the Huntington Community was developed, Alexandria experienced a rapid wave of development that continued into the early 1990s. High rise apartments, office buildings, retail shopping centers, and residential communities were built throughout the watershed. And thus, impervious surfaces – asphalt roadways, parking lots, rooftops, etc. – replaced rain-absorbing forests, meadows and farms. The runoff from these impervious surfaces was directed to concrete storm sewers that emptied into Cameron Run. As a result, the stream was the immediate victim of this development; the adjacent landowners were the unsuspecting future victims.
Siltation from development, and then rerouting of the channel due to the construction of the Capital Beltway (I-495), altered the flows of Cameron Run dramatically. The floodplain of Cameron Run moved ever so precipitously towards the Huntington community. Homes that were once simply near to Cameron Run, were now solidly within it’s floodplain. Since the late 1960s the results have been devastating, and the community, Fairfax County, and the federal government are struggling to protect this modest community from the ravages of increasingly severe flooding. As rain events seem to be more severe and more frequent, possibly a result of climate change, the adjacent landowners are now grappling with ever-changing floodplain boundaries.
The solutions to this phenomenon that is playing out in many urban areas are complex. But as so well illustrated in the case of Cameron Run, proper restoration and protection of our nation’s floodplains should be of the highest priority as we continue to develop rural and suburban areas.
To read more about the issues associated with Cameron Run, click here:
Author Doug Pickford of Trout Headwaters, Inc. (THI), an environmental planner with 20 years of experience in the Chesapeake Bay area, follows events in the bay watershed as the tide turns from voluntary to mandatory for bay cleanup regulations and protections. Doug’s blog series for THI will document what is likely the largest and most significant watershed clean up effort in the history of the U.S., and offer his insights into some practical ways to assist the health of this magnificent natural resource