Silver lining behind historic flooding

Sep 30, 2013

The recent massive flooding in northeastern Colorado was a tragedy in lost lives, destroyed homes and lost agricultural crops, but there are some benefits coming out of the much needed moisture.

“There is a silver lining if we look down the road,” said Ron Carleton, the deputy commissioner of agriculture for the state. “We just have to get past these near-term impacts.”

According to reports, the State of Colorado receives the seventh lowest total rainfall among the 50 states, and 80 percent of that rain falls on the west side of the Rockies whereas 80 percent of the population lives east of the Rockies.

The Platte, Rio Grande, Colorado and Arkansas Rivers all originate in Colorado, making the state a top water exporter. The Arkansas is 1,469 miles long and the Colorado is 1,450 miles long. The Colorado and its tributaries are a major water source for New Mexico, Utah, Arizona, Wyoming, Nevada and California. The flooding hit the Platte and the Poudre river areas the hardest.

Most of the Platte lies above the Ogallala Aquifer, the largest underground water reservoir in the U.S., covering most of Nebraska and part of Wyoming, Colorado, Kansas, Oklahoma, Texas and New Mexico. The aquifer has also been at the center of a number of legal disputes in recent years. But the Colorado floods may help put some of the disputes to rest, at least for a while.

The Nebraska Department of Natural Resources, local natural resources districts, and irrigation districts in the Platte River Basin have taken steps to divert floodwaters out of the river as they moved into Nebraska from Colorado. These efforts consisted of developing agreements and coordinating the timing of the diversions of this flow in an attempt to attenuate the peak flood flows. The diversion of these floodwaters will have the added benefit of recharging the aquifer as these waters seep into the ground beneath the canals and lakes along the South Platte, North Platte, and Platte Rivers.

The flows on the South Platte River measured at the Colorado state line peaked at 21,000 cubic feet per second (cfs) on September 18. While flows are slowly receding, they are expected to remain elevated for several weeks. The diversions will continue as long as these excess flows are available in order to maximize the aquifer recharge benefits. These groundwater recharge benefits will be realized in both the Platte and Republican River Basins as this groundwater slowly percolates through the ground into these rivers and their tributaries over time.

These diversion projects were set up in a very short time frame as Nebraska braced for the large flows expected after the devastating floods in Colorado. The Director of the Department of Natural Resources, Brian Dunnigan, said “the expeditious work by all parties in developing and implementing these agreements is a wonderful demonstration of what can be achieved when all parties are able to work in close collaboration toward the same goal.”

This effort is similar to the diversion of flood waters carried out along the Platte River in 2011 by the Department and the local natural resources districts and irrigation districts, which also provided significant flood mitigation and aquifer recharge benefits.

But there is no denying that the silver lining is just a small blip on the bigger scale of the flood damage.

A record 17.15 inches of rain fell along the Front Range in about a week, nearly as much as the area usually gets in a year. The rain was so intense over a two-day period in some areas that meteorologists say it was a 1-in-1,000-year event, and the often stodgy National Weather Service described it as “biblical.”

Water surged across 17 counties and into Nebraska, killing at least eight people, destroying at least 1,800 homes and damaging more than 16,000 others. The flooding caused sewage and oil spills and demolished roads and bridges. Hardest hit were northern Boulder County and Larimer County.

The repair estimate for state-owned roads and bridges alone is $430 million, according to Micki Trost, spokeswoman for the Colorado Office of Emergency Management.

The state’s estimated cost for operating the State Emergency Operations Center, providing resources to local jurisdictions, and obtaining air and ground support from the National Guard is $19.5 million, she said. Air evacuations and other costs to the state for National Guard support amounted to $7.1 million of that total. — Traci Eatherton, WLJ Editor