You have to be very careful with so called springs. Springs can result from from water confined by soil or rock layers that finds a porous place where it percolates thru. If the groundwater levels are high the spring flows. If groundwater levels drop, water can leak from the lake back into the ground. Are there any wells in the area? If there are ask the owners what the water level is. It will give you a good indication of where the groundwater table is.