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24 <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 rides. <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 parr 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 Ynformatioin Provided to the Committee <br />i. 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 remediation 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 />Zn receiving this information, the .Committee noted that this draws attention to <br />the need far conservative pump sizing for new wells (please see Pinding 9 on <br />page 24). <br />17 <br />