"People look at the maps of the state that show the dots of irrigation wells, and they're dense in this area. And some people draw the conclusion because of all those wells there has to be a problem.
     "Not necessarily. What we found at the Natural Resource District in looking at this problem for a number of years is our groundwater is really – the groundwater level is really tied to the weather cycles. And we have taken a look at the groundwater changes, and we chart this.
     "So, we plotted this from 1961 to 2003, and we laid that rainfall change chart over the top of the groundwater decline chart and they match. Really close… So we're convinced that rainfall produces a lot of groundwater recharge for this aquifer. We're in windblown Loess soils of 70 to 100 feet thick – that's the yellow clays – and water moves through that fairly rapidly. Now it doesn't happen in one year, but it does move vertically through that. What happens, in the wet year, we have the recharge going on plus people aren't pumping as much. In a dry year, the water's not moving as much, but there's more pumping. So, that's what it's tied into."

John Turnbull – Surface & Groundwater


Other Excerpts from John Turnbull’s Interview:

John in Vietnam
Anti-War Protests
Consumer Preferences
Water Quality
Natural Resource Districts