Lawson recounts 2010 inflows in North Platte system
Casper – “I didn’t know how true it was when, back in April, I said I was looking forward to August,” says Bureau of Reclamation Wyoming Area Office Manager John Lawson when speaking of the 2010 water season on the North Platte River system.
“We’ve got water from one end of the basin to the other, and we’re trying to figure out what to do with it,” he says of the tremendous inflows central Wyoming experienced this spring.
“The system holds 2.8 million acre-feet, and on June 28 we had three million acre-feet in the system, because of the water spilling. Between June 1 and the end of September I’m attempting to evacuate one million acre-feet from the system,” says Lawson. “And we’ll still end with two million acre-feet in the system on Sept. 30.”
“When we started getting sustained inflows, we broke all historic records,” says Lawson. “At one point we had 20,000 cubic feet per second (cfs) coming into Seminoe, and we sustained over 19,000 cfs coming in for seven days. To put it in perspective, Guernsey Dam only holds 45,000 acre-feet, and in 24 hours we were receiving 40,000 acre-feet into Seminoe. We were basically getting a Guernsey Dam a day for seven days. Needless to say, the reservoir was filling at a dramatic rate.”
Lawson says Seminoe Reservoir holds 1.17 million acre-feet, and it was fast approaching 1.1 million. “I had to get this stopped, so we started releasing immediately. At one point we were releasing 16,000 cfs through the spillway at Kortes Dam through the Miracle Mile, and now we’ve got some work to do out there. All the nice fishing piers we had – they’re all gone,” he says.
In 1983 and 1984 high inflows there was an old wooden bridge on the Miracle Mile, and it was saved by cutting a new river channel on the right side of the bridge. “When I came here we had the new one designed and put in place, and I couldn’t remember what it was designed for, so I called the head designer, who’s retired now, and he said he thought it was 10,000 cfs, and I said it better not have been. We started ratcheting up the outflow, and we got to 16,000 cfs under the bridge, and we thought we might be able to crowd another 1,000, and I was prepared to tear out the right abutment to move water around the bridge,” explains Lawson.
He adds he was also concerned with the pine trees along the miracle mile, that their root systems might weaken and they’d head toward the bridge in the velocity of water that was flowing.
“So the 16,000 cfs outflow through the Miracle Mile meant that Pathfinder was going up, and we already knew we were running out of room,” says Lawson. “We started calculating how far we could drive Pathfinder up over the spillway, because the higher we could get Pathfinder built up over the spillway, the more storage space we had. Pathfinder holds 1.16 million acre-feet, and we had it close to 1.6 million acre-feet at the height of the spill. That’s when I started getting a hold of the emergency management people, from the head of Lake Mcconaughy and all points to Casper.”
“We didn’t really know where we were going. We were looking at the snowpack, and asking where it was coming from,” says Lawson. “What happened was the temperature dipped in April. It got cold and we didn’t have our normal runoff, the snow sat there and then we got more snow and rain. Then all the sudden it got really hot.”
“You cannot have a worse situation, than when you have cold that delays the runoff, then rain on top of snow. It’s your worst nightmare,” he says.
“On top of that, three years ago this September, in this system that was at three million acre-feet this year, we only had 700,000 acre-feet in the entire system,” says Lawson. “That’s how fast this thing has turned on us. Three years ago I was advising everyone that if we didn’t have a turnout we’d drain Pathfinder, and we’d have it as a flow-through.”
“We’re releasing 4,500 cfs out of Gray Reef right now, and we were releasing 7,000 cfs a little over a week ago. In Casper the flow got up to around 7,600 to 7,700 through Casper itself,” he says, adding that the only time the flow’s been higher was in 1983 when it almost reached 9,000 cfs. “I wasn’t looking forward to that, and I know that river has considerably changed and shrunk as far as capacity, and I knew the problems we had in ’83.”
“You’re seeing the water coming at you, and it won’t stop. For 20 days we had more than 12,000 cfs come into Seminoe, and we were trying to figure out where it was coming from and when it was going to stop,” he notes.
When Glendo Reservoir reaches the flood pool at 517,000 acre-feet the Corps of Engineers takes over releases. “They’re looking downstream at the flooding in Nebraska, and I’ve got no place to go, and they’re saying stack it. We got just under 720,000 acre-feet in Glendo before we got it stopped, and that was just over a week ago,” he explains.
“We’re releasing 7,000 cfs from Guernsey now, and we’ll release that much until the end of September. I will end this year with 300,000 more acre-feet than we even had last year, and I have to dump 200,000 acre-feet of ownership just to get it out,” he continues. “But I’m betting on the fact that we’ll have, even if it’s less than average next year, enough runoff to fill the ownership back up.”
Even releasing at that rate, Lawson estimates Glendo Reservoir won’t leave the flood pool until Aug. 7. “We’ll end Glendo this year with 240,000 acre-feet of water. Glendo was built to relocate Pathfinder water all winter, and we normally get Glendo down to 90,000 to 100,000 acre-feet by fall. This year I’ll sit at 240,000 acre-feet. I expect by May next year I’ll already be in the flood pool, easily.”
“We’re already running the numbers for next year. We ducked the bullet on this one, and we’re starting to figure out what kind of a bullet might come next year, and how we’re going to manage it,” he says. “It all came out good this year, and I’ve got a tremendous staff. We were here day and night running calculations, and people in the field 24/7 checking reservoir levels. If you’ve got a foot left on the spillway, in the middle of the night you want to make sure that gauge is working.”
“It’s a nightmare,” says Lawson of his job managing the North Platte River system, and others under his office. “It’s a nightmare, but it’s fun. But it’s still a nightmare.”