A Coyote Gulch reader (thanks Theo!) sent us this link [pdf] as a follow up to the Arkansas Valley Conduit story we ran yesterday (scroll through the document to page 8, Water Rights vs. Pollution Control Along the Arkansas River). It seems that flood irrigation is a major contributor to salinity in the Arkansas River. The river itself is high in natural salinity as a victim of it's geology.
From the article, "Ever since the first settlers plowed up the prairie along the Arkansas River, farmers have flooded their fields with river water to grow crops. They quickly learned that the river was naturally salty and located their towns near river tributaries to find fresh water. But today the Arkansas is slowly poisoning the agricultural economy it helped create. Salt buildup in farm soil has slashed crop yields and high salt loads in the river have forced rural communities to confront huge drinkingwater treatment bills, and provided a potential flash point of litigation between Kansas and Colorado, to say nothing of the impacts on stream ecology.
"The lower Arkansas River in Colorado is the saltiest stream of its size in the U.S. Its underlying problem is geology. The river picks up salt as it cuts through ancient seabed formations on its route through Colorado's southern plains. And traditional flood irrigation -- diverting river water across fields with canals,
ditches and pipes -- raises the salt content of the soil and the contaminant level of the river as it flows toward Kansas.
"Ongoing studies by Gates and other CSU researchers suggest the cycle of irrigation-amplified pollution can be broken but not without great expense. Gates said aging ditches, canals and other waterdelivery systems need to be rehabilitated and modernized; subsurface drainage systems must be installed and maintained; new and more salt-tolerant crop varieties will have to be planted. Widespread adoption of drip irrigation, which delivers water directly to crop roots, could help save farming and improve environmental conditions in the river, Gates believes. But the cost of installing drip systems -- up to $1,600 per acre -- deters many farmers."
Coyote Gulch linked to the original Denver Post article on February 27, 2005.
Category: Colorado Water
8:44:15 AM 
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