Agenda - 03-10-20; 8-f - City of Durham’s Teer Quarry Reservoir – Letter of “No Objection” from Orange County Related to the Voluntary Eno River Capacity Use Agreement

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Attachment 2 6 WATER MANAGEMENT CITY OF DURHAM October 29, 2019 Ms. Linda Culpepper, Director Division of Water Resources NC Department of Environmental Quality 1611 Mail Service Center Raleigh, NC 27699-1611 RE:Teer Quarry Operation and Eno River Capacity Use Area Dear Ms. Culpepper: The City of Durham (City) owns the Teer Quarry Reservoir located adjacent to the Eno River and needs to operate the facility under broader parameters than those currently permitted under the Finding of No Significant Impact (FONSI)for the Phase I Teer Quarry Supplemental Storage Project (2010) in order to meet the City's water supply needs.The City of Durham Department of Water Management (DWM) developed a broader set of water withdrawal and water supply access conditions in collaboration with the Division of Water Resources(DWR), the NC Wildlife Resources Commission (WRC) and the US Fish and Wildlife Service (USFWS), and presented those conditions to the Eno River Water Users at their annual meeting. The Durham Water System (City of Durham) is subject to the Voluntary Eno River Capacity Use Area (CUA) Water Management Operations Plan (WMOP), as are the Hillsborough Water System (Town of Hillsborough),the Orange-Alamance Water System, and Piedmont Minerals (now Resco Products).The WMOP was implemented as a result of low flow conditions during which the demand for water exceeded the amount of water available from the Eno River. With the exception of the City's withdrawal from the Eno River(downstream from US-501), the WMOP is based on Lake Orange water levels (upstream of the USGS Eno River Gage at Hillsborough) and Eno River flows at the USGS Eno River Gage at Hillsborough (US-70). See Figure 1 on the next page. The WMOP allows the City to withdraw 5 mgd from the Eno River when flows are above 30 cfs from March through May and above 10 cfs during other times of the year. The WIVIOP allows public water supply systems to withdraw additional water from the Eno River during periods of higher flow "provided that they have long-term contracts for obtaining an equal amount of water from outside the basin when the flow in the Eno River drops" (Eno River Capacity Use Investigation Water Management Operations Plan, p.4). The City has a Jordan Lake water supply allocation of 16.5%which is equal to 2,462 million gallons of water supply storage (estimated to reliably yield 16.5 million gallons per day), satisfying that requirement in the WMOP. The WMOP does not define the Eno River flow conditions for water withdrawals greater than 5 mgd.The DWM worked with the DWR,the WRC and the USFWS to develop and analyze a range of hydrologic modeling scenarios using the DWR's Cape Fear-Neuse River Basins Hydrologic Model to develop operational conditions under which the City can withdraw more than 5 mgd from the Eno River without negatively impacting the stream ecology or other Eno River users. 1600 Mist Lake Dr.Durham, NC 27704 919.560.4381 DurhamNC.gov Follow Us @CityofDurhamNC 1 00 0