Speaker: Irrigation wells not only concern for South Platte

GILCREST -- There are 10.5 million acre-feet of water under the South Platte River that is not being used and it's time the Colorado General Assembly allows irrigation well owners be allowed to use that water in drought conditions.

That was the message from Robert Longenbaugh Tuesday evening, who also said well users are not the only ones who are effecting the flow of the South Platte River, but "nobody is talking about those and they have more a more significant impact than wells."

Longenbaugh was the featured speaker at a meeting that drew about 250 people to the auditorium of Valley High School organized by Equity In The South Platte River Basin Committee. Longenbaugh spent 30 years with the State Engineer's office.

He charged that cities using transmountain diversion -- bringing water to the east side of the Continental Divide from the west side -- to extinction, evaporation of water from gravel pits along the South Platte, water conservation by cities, the use of pivot irrigation systems by farmers instead of row irrigation, conversion of irrigated land to housing development and trees along the river are among factors that have a greater impact on the flow of the river than do irrigation wells.

"All that has had an effect on return flows to the river, but nobody is talking about those impacts," Longenbaugh said, adding that it has been estimated that such things as non-native trees which have evolved along the river over the years use as much as 490,000 acre-feet of water a year. One acre-foot is enough to supply two families with a year's supply of water. In addition, such things as concrete lining of ditches have eliminated as much of 30 percent of seepage from those ditches -- water that would have returned to the river by seepage.

But most important, Longenbaugh said, is the 10.5 million acre-feet of ground water in the alluvial under the South Platte that could be used by irrigation wells during drought years without hurting senior surface water right holders.

"We have to think outside the box to manage and administer the river system top allow wells to pump and protect senior water right holders at the same time," he said.