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5.1.5.1 <br />Well Drawdown <br />Well drawdown is the decrease of water from <br />the baseline static water level. It can also be <br />described as a decrease in water elevation, <br />potentiometric surface, or water head. As a <br />well is pumped, drawdown is induced by the <br />removal of a volume of water from the <br />aquifer. As the well continues to operate it <br />can also create an area around the well <br />where water is drawdown. This area of <br />drawdown is known as a cone of depression <br />or the area of Influence from a pumping well. <br />When a well discontinues pumping, water from <br />surrounding aquifers will flow into the area and <br />bring water levels back to static levels. Pumping <br />temporary creates an area of low potentiometric <br />water pressure, and when the well is shut off <br />water will flow into the area to balance out that <br />change in potentiometric surface. This is known <br />as recharge, or recovery. The recovery period <br />like the drawdown is determined by the <br />hydrogeological properties of the aquifer. <br />Drawdown observed in the City of Ramsey wells <br />are typical for Twin Cities bedrock aquifers. The <br />following chart depicts a drawdown and recover <br />of Well 5 during a 2-day period starting May 3rd to May 5th in 2019. <br />Figure 3 — Terms Relating to Well Performance <br />Pump, 41a1e- Le, el m ma, Stain Weer <br />11..4yeil ] lI Y'f..h. r1 <br />s level lir. fL <br />1;tSk k I - 01 ft <br />FEASIBILITY STUDY - DRAFT RAMSY 154354 <br />Page 18 <br />