These parameters are key to characterizing groundwater-surface water relationships. This level tends to fluctuate over time because of seasonal changes in recharge rates. Also, groundwater extraction by well pumping causes a temporary drop in the water table level near the well. At the location of our sampling session, the water table was higher than the stream level, creating conditions for groundwater discharge to the stream. Flow rates of surface water are another way to help determine where water is coming from or going to.
Streams can either gain water from, or lose water to, the groundwater system.
Flow rates that are higher than can be accounted for by upstream flow indicate probable areas of groundwater discharge, while a decrease in flow rate indicates an area where the stream is recharging the groundwater. Specific conductance , which we measured using a meter, indicates the capacity of water to conduct an electrical current and commonly reflects the amount of dissolved minerals in the water. Changes in specific conductance along a stream reach can be used to help detect areas where groundwater is discharging to surface water. Nitrates were measured by LaMotte field test kits. The high nitrate level found at site 2 indicates a source of nitrate contamination upstream of site 2.