SAN LUIS VALLEY — Last year was a tough water year, and the snowpack in the Rio Grande Basin is currently well below long-term average, but this region may see above average moisture through the summer months, Pat McDermott, Colorado Division of Water Resources Division 3, reported to the Rio Grande Roundtable group on Tuesday, Jan. 8.
McDermott’s report followed a dire report from Rio Grande Water Conservation District General Manager Cleave Simpson, who had also made a presentation earlier in the day to the Alamosa County commissioners.
McDermott reminded the Roundtable members how dismal 2018 was, with one of the few consolations being less water required to be sent downstream because there was less water to send.
Preliminary numbers indicate the annual flow of the Rio Grande at Del Norte in 2018 was 282,000 acre feet, or 44 percent of the long-term average. The obligation to downstream states through the Rio Grande Compact was 71,400 acre feet, or about 25 percent. The year before (2017), the Rio Grande had produced 690,000 acre feet, with 29 percent of that obligated to downstream states. While 2018 was a year that produced only 44 percent of average on the Rio Grande, in 2017 the river produced 108 percent of average.
The Conejos River system also experienced an above average year in 2017 and well below average in 2018, with the only benefit being less was required to be sent downriver through the Compact, McDermott explained. The Conejos River system produced 440,000 acre feet or 143 percent of normal in 2017, with 51 percent of that owed to downstream states. In 2018, the Conejos River system produced only 160,000 acre feet, or about 52 percent of the long-term average, but only 25,000 acre feet or 16 percent of the index flow was obligated to downstream states.
McDermott also talked about when the rivers peaked in 2018, which is becoming a trend. While the Rio Grande might have historically peaked in July, it is now peaking in April and May and then quickly declining.
“We are seeing it year after year now,” he said.
The Alamosa River was a similar story in 2018, McDermott recounted, with an early peak out. He said in 2017 the basin had enjoyed some moisture spikes with rains. “We just never saw it in 2018.”
Trinchera Creek was the best performing stream in Division 3 (Rio Grande Basin) in 2017 but was the poorest performing stream in the basin in 2018. Mountain Home Reservoir and Smith Reservoirs were drained, which helped some but did not make a big enough difference, McDermott explained.
Snowpack in the Rio Grande Basin as of Jan. 8 was sitting at about 75 percent of the long-term average. McDermott was optimistic, however, that above average precipitation is predicted in the future for this area, with moisture coming up from the southwest.
He said above average precipitation is predicted all the way through July. He added that temperatures are also predicted to be warmer than normal. In 2018, he said, Alamosa experienced 2.5 degrees above normal.