Water year, Lawson concerned about 2011 inflows
Laramie – While recapping the 2010 water year, Bureau of Reclamation (BuRec) Wyoming Area Manager John Lawson said he’s already worried about next year.
“Everyone is saying how great our water year was, and they see it as a positive, but in June and July I was not that enthusiastic about it,” said Lawson of the water year in the North Platte system and its seven reservoirs under BuRec operation. Lawson spoke to the annual meeting of the Wyoming Water Association in Laramie in late October.
“We ran out of space, and it came as a surprise,” said Lawson. “In over 100 years of records, we’ve never had the inflow that occurred this year in Seminoe. At one point we were getting approximately 20,000 cubic feet per second (cfs) coming in. That may not mean a lot, but to put it in perspective, right now the North Platte is running at about 400 cfs. For five days, every 24-hour period we were filling two High Savery Reservoirs.”
Of the Pathfinder Dam spill, Lawson noted that, in his opinion, there is no dumber animal on the planet than the human being. He spoke of members of the public who would creep out on the wet rocks immediately next to the waterfall.
“I still shake my head, to this day. This was a tremendous waterfall – there were waterfalls coming down the other side of the canyon from the mist. They were crawling down steep rock with that wet situation, and if anyone had fallen in, that first step would have been a big one,” he said.
In the entire system, Lawson said being able to store more water by allowing Pathfinder to spill is what saved the situation. “That required us to keep raising it to store more water. It stores 1.16 million acre-feet, and we were up to 1.6 million acre-feet, and we thought we’d have to go farther than that.”
Lawson said 7,500 cfs was released through Casper, which required a tremendous amount of coordination. “We got a hold of the emergency management people, and all the counties and state reps from Nebraska and Wyoming. Every morning on Monday, Wednesday and Thursday we’d have a phone call to update them. I feel good about how everybody came together to manage it.”
After Seminoe and Pathfinder, the next significant reservoir is Glendo. “We were within a foot of topping Seminoe, were already two feet over the spillway at Pathfinder, and the Army Corps of Engineers was directing releases from Glendo,” said Lawson of Glendo entering the exclusive flood control pool. “We were releasing 7,500 cfs, and the Corps cut us down to about 1,000 cfs. We were passing 7,500 through Casper, and it was raining in the lower basin, and the Corps said to shut off releases. I’ve heard what a great walleye fishery that resulted in.”
“Everything was full – Gray Rocks filled and had 5,000 cfs coming out below our dams, and there was no place to take it, so we had to suck it up and take everything in Glendo,” he added. “There wasn’t a dry picnic table at Glendo, and the bad news was if you wanted to use a restroom on the 4th of July.”
When it was all said and done, Lawson said total space in the system is 2,787,000 acre-feet. On June 28 the system held 2,952,000 acre-feet. Three years ago, in 2007, the entire system held a mere 700,000 acre-feet.
“On June 28 we had three million acre-feet in the system, and this September we ended with two million acre-feet. Even to get to two million we had to evacuate out ownership,” noted Lawson. “We basically had to release 175,000 acre-feet in addition to demand to get down to two million, and that wasn’t an easy thing. A few irrigators are still questioning what I’m doing, because three years ago we were in a situation where we were just about out of water, and this year I’m ‘dumping’ water out of those ownerships.”
Lawson said the reason for evacuating the water is the snowtels, which measure snow water equivalent throughout the winter and spring.
“We got surprised this year, and we’re still not clear what the conditions were that occurred. This year’s snowpack on March 1 was well below average. In 2006 we were relatively well above average. On March 1 in 2006 we forecast 875,000 acre-feet of inflow, and this year we forecast 590,000 acre-feet on March 1.”
“We were going along with snowpack at low levels – not taking any action or releasing any water, and we were feeling pretty good about it,” he continued. “By April 1, we thought we knew what we were doing. Snowpack was still way down, but we increased the forecast to 650,000 acre-feet of water.”
“By mid-April our snowpack was dropping, and still considerably below average. When it started to go up a little, we increased the forecast to 800,000 acre-feet. When we got all done, we ended up with 2,242,000 acre-feet of water. In 2006, with above average snowpack all season, we ended up with only 546,000 acre-feet. Explain that,” said Lawson. “I can’t, other than that we started to get rain, and I’m interested in the bark beetle discussions. I think they did have some effect in what was going on, and the rate the snowpack came off.”
In 2010 the system received over two million acre-feet of water in a 12-month period, and 1.6 million of it came in the four runoff months.
Looking back to 1997, Lawson said the system received 1,072,000 acre-feet of inflow without a problem, but the snowpack was also above average way back in December. “In 1997 we evacuated water in March, April and May, and we didn’t get in trouble. If we have snowpack like in 1997, I can see the irrigator smiling, and he’s saying that I can dump some water.”
On the other hand, he says 2011 could be a year like 2002, when the system only received 118,000 acre-feet of inflow. “That gives you an idea of what we deal with on a year-to-year basis, and the swing we have. If we’re low, those gates will remain tight. If we’re in an above-average range in March and April, there will be some hard decisions, and I’ll look to a lot of people for advice,” he commented.
Looking ahead, Lawson said he’s worried about next year. “You’ve heard the horror stories about this year, but come next year, you tell me. I’ve got two million acre-feet in the reservoir. Come March 1, if I’m below average on snowpack, what do you do? Come April, if we’re still below average, what do you do? That’s the point. We’ll have to watch this very closely.”