From The Fort Morgan Times (Dan Barker):
[Robert] Longenbaugh said he has done research on water levels and South Platte River flows over the past few years with the assistance of John Halepaska. Longenbaugh has looked back at groundwater level records and contemporary well measurements — as well as South Platte River flow as it leaves the state near Julesburg — with the help of some funding from corn growers, he said. There is no state agency responsible for collecting groundwater data, and no state funding for the job, but there ought to be, Longenbaugh said. Growers had noticed springs in their fields where none had ever been seen before, as well as wet basements, he said.
Longenbaugh said he found that water levels fluctuate during the year due to a variety of factors such as pumping, augmentation water recharge, natural recharge and deep percolation. Continuous monitoring of wells in the South Platte basin seems to show that there are no long-term effects of previous pumping, he said. When nearby wells stop pumping, water levels quickly begin to rise and may return to pre-pumping levels within a few days or months, Longenbaugh said. In fact, water levels seem to return to equilibrium each spring, he said. Generally, levels will fall, during the spring and summer, but rise again during the fall. Groundwater levels have risen since wells were closed, and that shows artificial recharge has helped, but even areas where there was no recharge have seen water levels rise, Longenbaugh said.
He said well pumping seems to cause local cones of depression around the well, and continuous pumping causes those cones to deepen and expand outward. That causes less flow into the river. But when wells stop pumping, the cones begin to fill and river depletions to decrease, Longenbaugh said.
More South Platte River basin coverage here.