From The Pueblo Chieftain (Matt Hildner):
Too much water has become a bad thing in the Rio Grande basin. That might seem like nonsense in a region that has seen below-average stream flows for most of the last 12 years, but inaccurate stream forecasts coupled with the demands of the Rio Grande Compact have put water managers and users in a pinch. The compact governs how much water Colorado must send downstream and includes separate delivery schedules for the Rio Grande and Conejos River.
Those deliveries run on a sliding scale with the highest demands in wet years and the lowest ones in dry times. Each spring, the state engineer’s office relies on stream forecasts from the Natural Resources Conservation Service to balance how much runoff can be diverted by irrigators with how much must go to New Mexico.
The service draws that forecast partly from the eight automated snow gauges and a string of manual snow survey sights in the basin. But this year’s projections were low by roughly 50,000 acre-feet on the Conejos and almost 150,000 acre-feet on the Rio Grande, Division Engineer Craig Cotten said. That has left Cotten and his staff in the position of curtailing or limiting the amount of water that irrigators would otherwise be entitled to according to their respective water rights.
“The most senior water rights on both rivers are being curtailed dramatically in order to meet the compact,” Steve Vandiver, director of the Rio Grande Water Conservancy District told the basin’s roundtable earlier this month.
Moreover, the service’s snow measurement and forecasting program may have an uncertain future. Last year, the service proposed eliminating 47 of the 110 manual snow survey sites in Colorado to meet agency budget cuts. While those sites were saved, the threat of future funding cuts along with the inaccuracies plaguing the forecast have led officials in the Rio Grande basin to look at other options.
The Conejos Water Conservancy District is in the middle of a $237,000 project that will install a temporary radar system, six weather stations and a string of new stream flow gauges. The aim is to get a more accurate forecast that will reduce curtailments for water users. In 2012, the Conejos district estimated that those curtailments cost water users in the basin up to $13,000 per day.
“We can’t realistically blame Craig because it’s the forecasting error,” said Nathan Coombs, the district’s manager. “We don’t have anything else that helps us.”
The Conejos basin is home to two of the automated snow gauges run by the service.
The radar, which will be located either at Antonito or Alamosa, will give officials a clearer picture of where storms are happening, while the six weather stations will allow them to determine how much the storms are depositing.
Moreover, the project will add flow gauges to key tributaries of the Conejos such as Elk Creek and the South Fork of the Conejos.
“If we can start measuring better what these tributaries are doing, that will give us an indication of what these sub-basins are looking at,” Coombs said.
The snowpack and stream flow data gathered by the district will be turned over to researchers at the National Center for Atmospheric Research and the National Severe Storms Laboratory. In turn, those researchers will try to use that data to create a forecasting model. Coombs said the district will stack up that end product with the service forecasts.
“If there’s enough discrepancy to pursue it, that’s how we’ll go,” he said.
The Colorado Water Conservation Board played a role in funding the Conejos project and also has pursued the use of satellite technology to help increase the accuracy of snowpack measurement.
“We’ve had this conversation a lot,” Travis Smith who represents the Rio Grande on the board, told The Chieftain. “Forecasting drives our compact decisions.” Smith, who has been heavily involved in fire recovery issues in the Rio Grande’s headwaters, said temporary radar near Wolf Creek Pass that’s been installed to warn of late summer and fall monsoon storms, may end up playing a role for winter snowstorms as well.
But moving state officials toward improved forecasting can be difficult given that two of the biggest water management organizations in the state — Denver Water and the Northern Colorado Water Conservancy District — do their own forecasting independent of the service.
Still, Smith sees a potential ally in the Arkansas River basin, where water managers are dependent on service forecasting for its voluntary flow management program and reservoir operations.
Mike Gibson is chair of the Rio Grande Basin Roundtable, which also divvies up state funds for water projects and funded a portion of the Conejos pilot project. He wants all options left on the table.
“I personally feel we need to pursue all avenues available until we come up with a better system than we have now,” he said.
More Rio Grande River Basin coverage here.