Every 30 seconds another tanker truck, each representing the average monthly consumption of a family that doesn't water a lawn, would leave the lake headed to the mill. That's more than 100 trucks each and every hour. Not all industrial users are enormous. Some are just large. A sawmill or plywood plant with five acres of logs will pump a million gallons of water a day to keep the inventory wet.
Hydrologists can measure municipal and industrial consumption.
Less easy to gauge is agricultural consumption. No one knows how many irrigation wells have been poked into the Sparta the past two decades. And farmers, not as well organized but politically potent, are no more willing to sacrifice their claim to water than industrial users. More and more cultivated land is being irrigated to produce an increased diversity of crops. Flooding 100 acres of rice takes 30 million gallons of water and probably that much again to maintain the water level.