Interbasin Transfer

Press Enter to show all options, press Tab go to next option

In North Carolina, large surface water transfers between defined river subbasins are regulated through the requirement of an Interbasin Transfer (IBT) certificate from the Environmental Management Commission (EMC). The Town of Cary’s utility service area (including Morrisville and RTP South) and the Town of Apex’s utility service area straddle the boundaries of the Haw River subbasin (Jordan Lake is the water supply source), the Cape Fear River subbasin and the Neuse River subbasin. The Town of Cary obtained IBT certificates in 1989, 2001 and 2015 with terms that evolved to address current conditions and changes in IBT regulations. 

The 2015 IBT certificate, which addresses the needs of Cary, Apex, Morrisville and RTP South through 2045 based on the Long Range Water Resources Plan, allows transfers from the Haw River subbasin to the Neuse River subbasin up to 31 million gallons per day (MGD), and from the Haw River subbasin to the Cape Fear subbasin up to 2 MGD, calculated as a daily average of a calendar month. The following plans were developed in compliance with the certificate conditions: 

The IBT certification requires the Town to submit annual reports to the NC Department of Environmental Quality (NC DEQ), which manages the IBT certification process. View annual reports and background materials on the 2015 IBT certificate and previous IBT certificates, including environmental documentation summarizing IBT impacts.

Monthly Interbasin Transfer Amounts (million gallons per day)

Month and Year    Haw to Cape Fear     Haw to Neuse 
 Jan 2020 0.01 11.8
 Feb 2020 0.01 11.9
 Mar 2020 0.02 12.7
 Apr 2020 0.02 12.1
 May 2020 0.03 13.3
 Jun 2020 0.06 14.7
 Jul 2020 0.09 15.9
 Aug 2020 0.06 15.4
 Sep 2020 0.04 14.5


Sarah Braman
Water Resource Engineer
(919) 462-3846