From the Taos News (J.R. Logan):
Streamflow data from the Colorado Division of Water Resources showed the Río Grande was flowing at 1,330 cubic-feet per second (cfs) when it came out of the mountains near Del Norte, Colo Wednesday (April 30).
But by the time it was just about to cross the New Mexico border, it was at just 209 cfs.
The 84 percent drop is due almost entirely to irrigation in the San Luís Valley, which begins in earnest around this time of year.
A hydrograph of the Río Grande near Cerro showed the river was hovering at nearly 700 cfs between the end of February and the end of March. But starting at April 1, the streamflow at Cerro begin to plummet. At one point in mid-April, the river in New Mexico was at just 100 cfs.
The amount of water in the river as it crosses state lines is dictated by the Río Grande Compact — a deal hashed out between New Mexico, Colorado and Texas in the 1930s…
Water officials in New Mexico and Colorado say Colorado has met its legal obligation in recent years. The total water delivery from Colorado is calculated on an annual basis, meaning water that runs unimpeded in the fall and winter makes up for big diversions in the spring and early summer.
Taos County residents — especially some rafting guides — have been vocal critics of the arrangement, which they say does harm to their business and affects the ecology of the river.
Farmers and water managers in the San Luís Valley, meanwhile, point out that they too are suffering from the effects of drought and are operating within the limits of the compact.
From Reclamation via the Loveland Reporter-Herald:
With runoff starting to increase in the Big Thompson Basin, the Bureau of Reclamation bumped up outflow from Olympus Dam, at the east side of Estes Park, into the river Monday morning.
Kara Lamb, public information officer for the agency, said the flow was gradually increased through the day from 40 cubic feet per second to about 140 cfs.
“The heat over the next few days will likely increase nightly runoff inflows to Lake Estes, which will pass on through Olympus Dam to the canyon,” she said in a press release, adding, “So far, runoff inflows have been typical for this time of year.”
Warm weather has started melting mountain snowpack, leading to the increase in river flow.
On Friday Lamb had reported runoff inflow reaching up to 200 cfs at night. Runoff typically reaches its peak at night as water from snow that melted during the day heads downstream.
Lamb said it’s possible there could be more increases in outflow into the Big Thompson on Tuesday.
Last week, the bureau diverted some of the runoff inflow to the Colorado-Big Thompson Projects reservoirs, including Carter Lake and Horsetooth Reservoir.
By Friday, Carter Lake was at 98 percent of capacity, and more water was being diverted to Horsetooth. By Sunday it was reported at 88 percent full.
From email from Reclamation (Kara Lamb):
We’re still making space for the upcoming runoff on the Blue River. As a result, about an hour ago, we bumped up releases from Green Mountain Dam to the lower Blue by 50 cfs. We are now sending about 950 cfs on downstream.