Recharge rises as CO flooding recedes
Driven by up to 20 inches of rain, flooding rampaged parts of Colorado last week and, although the water has started to recede, the damage and loss from the torrential moisture is only helping to crystallize just how much work residents now face in rebuilding and recuperating.
The scope of the flood damage is broad, and the statistics surrounding the rainfall event are staggering: "Colorado State Climatologist Nolan Doesken indicated that numerous stations around Boulder recorded a year’s worth of moisture during this 1,000-year event," says University of Nebraska Extension state climatologist Al Dutcher. "In a span of three days, [the city of] Boulder [Colorado] went from the driest year to date to the wettest year to date on record."
As residents start cleaning up the flood's damage, there is a silver lining: The moisture has recharged the region's lakes and reservoirs, and points downstream will likely benefit from the rains, Dutcher says.
"Among all of the devastation that has and will likely occur with this historical flood event, there are some potential benefits that could materialize after the water recedes. The South Platte channel will be scoured of vegetation, and a greater volume of water will flow through the channel instead of being tapped by growing vegetation," he says in a university report. "Colorado reservoirs within the South Platte Basin are now full, so water supply issues for metropolitan areas have been eliminated."
Stream recharge typically happens in eastern Colorado and western Nebraska during the spring when Rocky Mountain snowfall begins to melt. In some years, that can tax the region's water management systems. That could be the case in the next few days as more water makes its way through the Platte and Missouri river systems. The immediate downstream effects will be felt in western Nebraska, but water making its way east from the Rockies will help make up for a dry year.
"With soil surfaces currently saturated in mountainous areas, a greater than normal portion of this winter’s snowpack will run off and subsequently increase flows along the South Platte River next spring," Dutcher says. "The expected increase in flows this spring also may impact Lake McConaughy water levels, even though none of this flood water will directly flow into the reservoir. The increase in flow along the South Platte this spring could give the Central Nebraska Public Power and Irrigation District (CNPPID) the flexibility to divert water into irrigation canals instead of releasing water from McConaughy. Thus, CNPPID may be in a similar position to 2011 when above-normal South Platte flows allowed them to capture spring snowmelt on the north branch of the Platte River that would enter into Lake McConaughey. Typically, a portion of the North Platte flow into Lake McConaughey would be diverted and passed downstream to fill early season irrigation obligations."