Although global warming has increased precipitation intensity and variability over most land areas, climate change alone does not explain the increased frequency of flooding events in Chapel Hill. The town’s population has grown 43% over the last two decades – that means less tree cover and more pavement. Engineers and stormwater professionals have known for years that when the natural forest floors are replaced by buildings, roads and parking lots, more water runs off the land at a greater rate. The high volumes of fast-moving water scour out our stream banks and diminish water quality for both humans and wildlife. In big storms, the low-lying areas flood. Just last December, 34 people were evacuated from the Camelot Apartments during a flood event. See story
and pictures in Chapelboro’s Chapel Hill Floods.
Chapel Hill resident Del Snow keeps track of the amount of new impervious surface resulting from the new construction the Town government has approved (including projects not yet built). The figures are staggering. She reports that in the Little River Watershed alone, which includes both Bolin Creek and Booker Creek watersheds, an estimated four million square feet of land that currently absorbs rainwater will be turned into impervious surface. It would be foolhardy to think that a substantial increase in impervious surface won’t result in serious consequences.
What can we do to prevent flooding and damage to homes and property? There is no one simple fix. For a start, towns could integrate watershed planning into the land use map to inform and guide the review of new development proposals during application reviews, rather than it being an afterthought.
Currently, Chapel Hill’s Planning Department begins development review without addressing basic questions such as assessing if the land can support a proposed development. Stormwater analysis often comes along much too late in the review process to ensure the use of proactive approaches which would require enough space to use the best practices in stormwater management.
The good news is that Chapel Hill has begun watershed studies in the Booker and Bolin Creek Watersheds. The data obtained from the current lower Booker Creek watershed study now underway will inform the town about future planning and zoning decisions. See www.lowerbookercreeksws.org.