Recharge conduits and sinkholes quickly become filled up with water. This is why the region floods so easily. The Edwards is not a good storage Aquifer where water can be placed and expected to stay for use tomorrow. Transmissivity is high enough that as long as the level of the Aquifer is above the elevation of springs, substantial amounts of water will flow out. We can artificially increase recharge to the Aquifer, but nothing will help us in times of prolonged drought.
Average rainfall means nothing here.
Dealing with the region's water problems always seems to come back to the issue of having some kind of storage available to put surpluses when they occur. The level of the J-17 index well drops about one foot for each 40,000 acre feet of water discharged from springs and wells. During peak pumpage periods in the spring and summer the level can easily fall over one foot per day. When the level of the J-17 well gets below about 650', the rate of decline slows somewhat and no one really understands why. Theoretically, there is enough water in the Aquifer to supply the region for 200 - 300 years, even if another drop of rain never fell.