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Figure 4 — Well 5 Drawdown and Recharge <br />860 <br />840 <br />F 820 <br />c 800 <br />a 780 <br />w <br />760 <br />au <br />J <br />+; 740 <br />720 <br />700 <br />0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 <br />O O N CO 10 O N 03 10 O N N 1 N • 10 N O CO • 0 N- CO O O N CO 10 O N CO 10 O N N 1 <br />.. .. .. .. .. .. .. .. .. .. CO.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. CO .. .. .. .. .. <br />O 00 (0 N O r— (6 .7 0) CO O 00 0 Cr) C3) r- 0') N QO (0 0 N 1 .7 O C9 O 0) 10 Cr) 0) N N 00 <br />O CO O Cf) N 010 N 10 CO N- O CO N O LC) N 10 N- O CO O LC) CO 03 O • Cr) O LC) CO N 10 N <br />.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. (Si.. .. .. .. .. .. .. .. .. .. .. (Si.. .. .. .. .. .. .. (Si.. .. .. .. .. <br />O O M 4� (0 00 00 O N Cr) LC) O N 00 O O M O.7 M 10 (0 00 00 O M 10 (0 N 00 O O (46 O r Cr) 4 <br />NNNN NNNN <br />Time <br />Well 5 <br />Drawdown and Recharge <br />May3-May5th <br />itet' <br />5.1.5.2 <br />At the start of this period, Well 5 water levels were recovering to static at approximately 23 feet <br />below ground surface. Pumping commenced at 15:15 on May 3rd and continued for the next 18 <br />hours. Initial drawdown or instantaneous drawdown is depicted by the step increase in drawdown <br />from 16:51 to 18:27. Water levels over this period fell 80 feet. Water levels over the following 18 <br />hours decreased another 40 feet. The well ceased pumping at 10:30 on May 3rd and recharge to <br />the aquifer took 17 hours to return to static water levels. <br />Current well pumping and rates of recharge appear good with the aquifer being able to recharge <br />water to static in a relatively low period of time. <br />Drawdown end AvAilable HPAd <br />Water levels from the source water aquifer, the Tunnel City-Wonewoc Aquifer, are much higher <br />than the topographic elevation of the top of bedrock. This scenario is known as a confined <br />aquifer, where the potentiometric surface, or water head, is higher than the topographic location <br />of the aquifer. <br />Presently, water quantity throughout the region is good and there are no regulations actively <br />being enforced on pumping levels within a well. Well interference and long-term groundwater <br />trends through pumping/drawdown is conducted on a case by case basis by the Minnesota DNR <br />if a problem arises. <br />Typically, it is not a good idea to drawdown water levels in a confined aquifer below the top of <br />bedrock as it can introduce oxygen into the formation. Additionally, water levels should stay <br />sufficiently above the specifications of the water pump design. <br />FEASIBILITY STUDY RAMSY 154354 <br />Page 19 <br />