2008 report of the water allocation study of the NC Environmental Review Commission. - Page 19 |
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2008 Water Allocation Study Team Report 15 communities’ ability to grow and prosper. Others believe that water availability within a given basin should be viewed as a limit on growth in that basin. Still others believe that allowing easy transfers encourages communities to waste water and to avoid enacting efficiency and conservation measures that would be more sustainable ways to supply water. However, views about interbasin transfer tend to be driven by assumptions about what those transfers are like, and the assumptions are not always grounded in fact. The NC Chapter of the American Waterworks Association ( AWWA) produced a white paper on interbasin transfers on December 19, 2006, authored by Barry Gullet, PE, of Charlotte- Mecklenburg Utilities, then chair of the NCAWWA. This is a good summary of how past and current IBTs in North Carolina actually work. Although IBT permits need to be reviewed comprehensively, there can be clear benefits to allowing these transfers, and it is possible that the complexity of the certification process discourages beneficial transfers. Specifically, transfers can increase water supply reliability, delay the need for building reservoirs and treatment plants, and reduce environmental impacts. Water supply reliability can be increased and costs reduced by the cooperation of water utilities entering into water transfer agreements, such as interconnects, that take advantage of variability in excess capacity and in supply and water usage patterns between the water systems. This variability may be higher in systems in different basins compared to ones in the same basin because of geographical differences in land use and weather. As a result, IBTs may allow even greater benefits. Structurally augmenting supplies ( e. g., reservoirs, wells) is becoming increasingly costly while also imposing unpopular environmental impacts ( Gleick 2000; NRC 2001). A given geographical region will likely have a limited number of viable supply- enhancement options. This is particularly true in the fast- growing headwaters regions of North Carolina’s Piedmont. It can be economically and environmentally beneficial to develop the best option and share it with neighboring systems, even those in other basins, to prevent development of more expensive systems in more environmentally sensitive areas. IBTs are typically requested to meet projected ongoing demand, and once the IBT certificate has been granted, utilities can withdraw up to the allotted amount given they meet the other conditions of the certificate, which may include implementing drought- management measures during times of drought. Conditional withdrawals are another option that preserve much of the gains in reliability and cost while minimizing total transfers. Work with interconnects ( Palmer 2006) between three utilities in North Carolina’s Triangle area shows that by allowing transfers only under certain conditions ( a utility having fewer than a specified number of days of supply remaining or having a risk of failure above a certain level), the volume of water transferred is reduced by 60% to 80% over a simple daily transfer cap. Although this work considered transfers of finished water between communities, it should also apply to transfers of raw water. The IBT certificate process has its own costs that make it more difficult for systems, especially small ones, to cooperate. According to Tom Fransen, River Basin
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Title | 2008 report of the water allocation study of the NC Environmental Review Commission. - Page 19 |
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Full Text | 2008 Water Allocation Study Team Report 15 communities’ ability to grow and prosper. Others believe that water availability within a given basin should be viewed as a limit on growth in that basin. Still others believe that allowing easy transfers encourages communities to waste water and to avoid enacting efficiency and conservation measures that would be more sustainable ways to supply water. However, views about interbasin transfer tend to be driven by assumptions about what those transfers are like, and the assumptions are not always grounded in fact. The NC Chapter of the American Waterworks Association ( AWWA) produced a white paper on interbasin transfers on December 19, 2006, authored by Barry Gullet, PE, of Charlotte- Mecklenburg Utilities, then chair of the NCAWWA. This is a good summary of how past and current IBTs in North Carolina actually work. Although IBT permits need to be reviewed comprehensively, there can be clear benefits to allowing these transfers, and it is possible that the complexity of the certification process discourages beneficial transfers. Specifically, transfers can increase water supply reliability, delay the need for building reservoirs and treatment plants, and reduce environmental impacts. Water supply reliability can be increased and costs reduced by the cooperation of water utilities entering into water transfer agreements, such as interconnects, that take advantage of variability in excess capacity and in supply and water usage patterns between the water systems. This variability may be higher in systems in different basins compared to ones in the same basin because of geographical differences in land use and weather. As a result, IBTs may allow even greater benefits. Structurally augmenting supplies ( e. g., reservoirs, wells) is becoming increasingly costly while also imposing unpopular environmental impacts ( Gleick 2000; NRC 2001). A given geographical region will likely have a limited number of viable supply- enhancement options. This is particularly true in the fast- growing headwaters regions of North Carolina’s Piedmont. It can be economically and environmentally beneficial to develop the best option and share it with neighboring systems, even those in other basins, to prevent development of more expensive systems in more environmentally sensitive areas. IBTs are typically requested to meet projected ongoing demand, and once the IBT certificate has been granted, utilities can withdraw up to the allotted amount given they meet the other conditions of the certificate, which may include implementing drought- management measures during times of drought. Conditional withdrawals are another option that preserve much of the gains in reliability and cost while minimizing total transfers. Work with interconnects ( Palmer 2006) between three utilities in North Carolina’s Triangle area shows that by allowing transfers only under certain conditions ( a utility having fewer than a specified number of days of supply remaining or having a risk of failure above a certain level), the volume of water transferred is reduced by 60% to 80% over a simple daily transfer cap. Although this work considered transfers of finished water between communities, it should also apply to transfers of raw water. The IBT certificate process has its own costs that make it more difficult for systems, especially small ones, to cooperate. According to Tom Fransen, River Basin |