The North Platte River System has more water now than it has had in eight years, but continued average moisture is required or the system will return to critical low levels, according to the Bureau of Reclamation.

John Lawson, area manager for the Wyoming area office of the Bureau of Reclamation, said at a meeting Wednesday in Torrington that he had brought bad news about water levels for the last seven years, but at this meeting he could report that 2008 was a good year for water in southeast Wyoming.

However, he cautioned that the increased water level “can go away as quick as it came.”

“We are predicting 748,000 acre-feet of water into Seminoe Reservoir between April and July,” Lawson said. “This is optimistic unless you think the weather has changed. If we get 750,000 acre-feet we will only be able to maintain the same type of carryover.”

To increase water in area reservoirs, Lawson said the area needs inflows greater than 750,000 acre-feet (acf). He also said some conservation actions would be necessary in order to leave as much water as possible.

“You folks have really been doing a good job these last few years. Everyone continued to comply with conservation measures,” he said.

There is more water in Seminoe and Pathfinder reservoirs in 2008 than last year. The Bureau of Reclamation forecasted April–July 2008 inflow to Seminoe Reservoir of 850,000 acf based upon the snow pack; the actual inflow was 955,900 acf. The Alcova to Glendo Reservoir inflow projection for April-July was 100,000 acf and the actual was 209,300 acf. The increase was attributed to the heavy eight-inch rain in the Guernsey/Glendo area in late May. The Guernsey Reservoir outflow for 2008 was 939,100 acf, slightly above the 2007 figure of 892,700 acf.

After all the water changes, at the end of September 2008 the North Platte System storage was over 1.19 million acf, compared to 706,300 acf at the same time in 2007. These figures are similar to those recorded in 1992, when the total system storage was at 722,900 acf at the end of September. In 1993, a total inflow of 1.57 million acf provided for a total system storage recovery to 1.22 million acf by the end of September.

According to Lawson, as of Oct. 1, 2008, Seminoe Reservoir was 53 percent full; it was 22 percent full at the same time last year. Pathfinder was at 34 percent compared to 17 percent the previous year.

Seminoe and Pathfinder reservoirs hold just over 1 million acf each; the whole North Platte System holds 2.8 million acf.

There were 1.19 million acf in storage in the North Platte System on Oct. 1. The 30-year average is 1.43 million acf. For the April-July inflow the Bureau projects a probable 959,700 acf inflow and a minimum of 414,700 acf. The 2008 April-July inflow was 1.27 million acf - the 30-year average is 930,100 acf. Annual inflow is projected at 1.32 million acf with a minimum of 692,100 acf. The 2008 annual inflow was 1.58 million acf and the 30-year average is 1.329 million acf.

“You have climate variability here,” Lawson said. “The wettest period for this area was from 1900 to 1950. There are indications that even with the late snows and 950,000 acre-feet of inflow, there is earlier runoff. There was no runoff 2-3 weeks earlier than the 10-year average. We had zero runoff on 15 June this year even when we were way above average in moisture. Rain is the wildcard in the lower reach.”

Lawson said the Wyoming Water Development Commission is funding a private consultant to design the Pathfinder Modification Project. This project would raise the elevation of the existing spillway by approximately 2.4 feet to increase the capacity of Pathfinder Reservoir. The 54,000 acf increase will recapture space lost to sediment. Construction could start as early as a year from now but is contingent upon a change of use for the water rights. The change of use has been filed with the Wyoming Board of Control but water users above Pathfinder Reservoir are concerned that the change could result in lowering their water entitlement.

“I am very encouraged that we will have success with those opposed to the change of use,” Lawson said. ”We should see construction within a year and two at the most.”

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