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r 0024 <br /> The areas of the lowest well yield contours were generally in northeastern, <br /> central and southeastern Orange. <br /> One finding of the study did not support an expected hypothesis. Previous <br /> studies have shown that, in other areas of the Piedmont of North Carolina, there <br /> was a relationship between the topography of the land and the well yield, such <br /> that the average yield in valleys and draws was nearly three times greater than <br /> wells on hills and ridges. <br /> However, the Orange data shows well yields have little or no relationship to <br /> topographic setting. This pattern is more similar to the Piedmont of Georgia and <br /> Alabama than to the rest of the Carolinas. This may be due in part to the fact <br /> that there is a difference in the way the County's underlying bedrock relates to <br /> surface drainage patterns. <br /> These data are then combined with the findings of the 1996 report to address <br /> ground water availability. <br /> C. Other Information Provided to the Committee <br /> 1. Discussion of Optimizing Existing Wells <br /> Ray Sparrow, a local well contractor, presented information to the committee <br /> regarding the use of"down-hole" cameras in wells to diagnose well problems <br /> and possible remedies, such as appropriate installation of liners. Sparrow found <br /> that the cameras prove to be a useful tool in remediabon of wells that have <br /> become susceptible to contamination and yet can be successfully repaired by the <br /> installation of a properly placed liner and packer. Cameras are also a useful tool <br /> in assuring that new wells are constructed properly. <br /> The discussion also entailed the need for proper set-up of the well pump in order <br /> to optimize each well. This approach matches the pump size, pump depth, and <br /> storage and pressure system to the characteristics of that particular well. A <br /> common practice contrary to this has been to oversize pumps and set them too <br /> deep. This results in excessive drawdown of the water column which aerates the <br /> well wall and fracture zones. This leads to formation of slime bacteria, iron <br /> bacteria and a buildup of minerals in the fracture zones which reduces the well <br /> yield over time and causes water quality problems for the user. <br /> Generally, these wells do not have to be replaced, they can be rejuvenated and <br /> the original yield can be restored by appropriately treating the well with the <br /> application of acids or special cleaning agents, or by methods using hydrostatic <br /> pressure to physically clean the well out the well. <br /> 17 <br />