Citing conflicting data, the Southern Environmental Law Center, a Charlottesville, Va.-based advocacy group, has called on the Durham County Board of Commissioners to reject a developer-funded survey of Jordan Lake, and commission an independent survey of the reservoir. The group based its recommendation on data collected in 2007 for the N.C. Floodplain Mapping Program that show Jordan Lake extending beyond a margin set in the 1970s by U.S. Geological Survey maps.
The controversial developer-funded survey, by contrast, shows Jordan Lake contracting in the opposite direction, thus removing property owned at the time by private developer Neal Hunter from a protected area surrounding the reservoir. In letters to state and county officials, Hunter's associates have argued the survey--which Hunter commissioned in 2005--represents "better information" than the 1970s maps, and used the difference in mapping technologies as justification for bypassing a public hearing process required by state law to implement zoning map changes.
The 2007 data SELC presents was collected via a technology known as Light Detection and Ranging (LiDAR), used by NASA and the National Oceanic and Atmospheric Administration to analyze topography. In a March 20 letter (PDF), SELC Staff Attorney Kay Bond notes that the LiDAR data "cannot substitute for an on-the-ground-survey" such as Hunter's, but "can give an accurate enough approximation of actual conditions to indicate whether the conclusions reached by a survey are generally valid."
Bond implies that Hunter's survey--which only analyzed the portion of Jordan Lake affecting his property--may not be completely accurate:
Based on these maps, it appears that the original Jordan Lake boundary recognized by USGS is a conservative one. These maps call into question the surveys submitted by the City of Durham in support of its request to adjust the watershed boundary for Jordan Lake.
View a PDF of SELC's maps, which include Neal Hunter's 2005 survey, and the original U.S.G.S. survey, here.