By Steve WrightGeneral ManGer Chelan County PuDsteve.wright@chelanpud.org

When word first arrived at Chelan County

PUD on Feb. 27 that there was a crack in Grant County PUD’s Wanapum Dam just downstream from Rock Island Dam, I have to admit to feeling concern for our friends at Grant PUD. It was shocking that a crack could form.

Yet as the Wanapum reservoir kept receding in the days that followed the initial discovery of the crack, and Grant PUD’s attempts to stabilize the dam, it became very clear that there was potential threat to our own operations. Let me take a moment and tell you why and how the lowering of a downstream reservoir impacts us in Chelan County and what we have done to lessen the financial impact to our customer-owners and what we have done to improve the situation for irrigators, river recreationists and for the fish.

How Can Lowering the Wanapum Reservoir Affect Rock Island Dam?

The most frequently asked question I get is why would lowering the river downstream of Rock Island make any difference, since Wanapum was built more than twenty years after Rock Island? The simple answer is today’s Rock Island Dam is very different than the Rock Island Dam before Wanapum was completed in 1963. For example, some of you may remember that the Rock Island reservoir was raised more than six feet in 1978 to add another powerhouse. Also many of the turbines and generators have been built or redesigned and replaced since Wanapum became operational. All of the engineering behind these changes was based on an expected Wanapum reservoir level that dropped dramatically in late February.

The second most frequently asked question is, “Why does the level of the reservoir downstream make any difference at all to the operation of the upstream

reservoir?” That is, why did Chelan County PUD have to lower the Rock Island reservoir when the Wanapum reservoir was lowered? The reason is that there is a direct relationship between the upriver and the downriver water levels when it comes to incredible river forces on a dam.

Our generating equipment is designed for a specific water elevation difference between the upstream side and the downstream side of the dam. If the downstream reservoir is lowered beyond design standards, the water pressure on the upstream side of the dam increases. The risk is potential catastrophic damage to the hydro-generating equipment - risking human health and safety and potentially costing millions of dollars to repair.

The situation at Wanapum Dam put the Rock Island generating equipment at an operating level that would be outside the limits of previous testing. When we found ourselves very suddenly in an untested state we chose to respond cautiously and conservatively to protect the long term viability of the assets that are so incredibly valuable to Chelan County and to ensure public and employee safety. As stewards of assets owned by the people of the county, it is our responsibility to act prudently.

Major Considerations – Agriculture, Recreation and Fish

Since Feb. 27, we have been in regular contact with

our colleagues from Grant

PUD. They have identified the root cause of the crack and are working mightily to find solutions that will restore the dam pier and will allow them to safely raise the Wanapum reservoir. Based on our regular communications with them and information they have released, we are operating under the premise that the downstream situation will remain as it is today at least until the last quarter of 2014

After learning that there wouldn’t be a quick “fix” for the Wanapum situation, Chelan PUD engineers quickly developed a series of accelerated engineering studies that were tested by third parties to give us confidence that we could adjust the elevation of the Rock Island reservoir up approximately two feet to an elevation of 609 feet above sea level on the upstream side of Rock Island Dam. With a minimum river flow upstream of 45,000 cubic feet per second (cfs), it meant that we could resume power generation cautiously. The studies gave us confidence we could operate Rocky Reach within the normal elevation range.

We were able to gain agreement from the Bonneville Power Administration and the Bureau of Reclamation to ensure that Chelan PUD would have 45,000 cfs river flow through October 15 of this year. This should allow us to maintain a sufficient headwater at Rock Island Dam to keep the level at 609’. Since then, aggressive efforts to complete engineering

Right Bank

POWERHOUSE 2POWERHOUSE 1

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CHELAN COUNTY

ALCOA

Rock Island Fish Ladder Extension

CenterFish Ladder

Right BankFish Ladder

Location #1Complete

4/15

Location #2Complete

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Location #3Complete

6/30

Left BankFish Ladder

River Flow

studies have put us in a position to produce roughly 90 percent of the normal Rock Island output, minimizing financial consequences.

Agriculture

While we are not an irrigation agency, we definitely understand the importance of irrigated fruit trees to our community. We held a public forum on March 13 with irrigators from Chelan and Douglas counties who draw water from the Rock Island reservoir. Our partner in this effort was the Washington Horticulture Association and representatives from state and federal agencies were on hand to answer questions for irrigators and what they would need to do if their irrigation intakes needed to be permitted for an extension due to the response to the Wanapum Dam situation.

On March 22-23 we ran a test by lowering the Rock Island reservoir to approximately 608 feet. We did that because we believed that would likely be the lowest the reservoir would operate during the summer. We wanted irrigators to be prepared for the potential impact on their pumps.

We continue to provide irrigators real-time information on our website (www.chelanpud.org Wanapum Dam Response) and a hotline number (509-661-8000) so they can make decisions about what they need to do to protect their investment.

Recreation

Perhaps our biggest unanswered question is how river levels this summer will affect the three public boat ramps on the Rock Island reservoir. It is likely that they will be inoperable below the 609’ level. Right now, all three boat ramps are usable. This is due in large part to snow melt and spring runoff. We don’t know how long we will be able to enjoy these higher river flows. Our backup plan is seek permits to extend one of the three public boat ramps, most likely the Kirby Billingsley boat ramp located on the Douglas County side of the Rock Island reservoir.

We are working toward an early August completion, if all of the necessary permits are received. We are committed to keeping the reservoir accessible to boaters and fishers and we will put forward our best effort to make it happen.

Fish

We have a huge investment in fish protection that is threatened by the drawdown. Juvenile and adult fish passage will work normally at Rocky Reach Dam. At Rock Island Dam we anticipate juvenile passage should also be as effective as during more normal conditions.

In order to address adult fish migration upstream, the adult fish ladders will work as long as flows are high. However, in the event of low river flow conditions, the ladders may be inaccessible. We entered into emergency contracts to extend three of the ladders so they will work under all foreseeable flow levels. Teams

on the ground and dive teams in the water worked night and day to install the ladder extensions in very difficult, turbulent

water conditions. They completed the extensions on the two ladders on the Chelan county side of Rock Island Dam in mid-April and the third extension on the Douglas county side of the dam will be completed in June. The ladder extensions are being modified to support passage of lamprey. The good news is that we are seeing normal fish passage so far.

Good News Through the Challenges We Face

We unexpectedly find ourselves in uncharted

waters. I feel fortunate to be surrounded by people here at the PUD who recognize that this is an emergency situation that requires extraordinary effort. Our colleagues in the federal, state and tribal agen-cies who have a stake in how the river is managed also rec-ognize the significance of the Wanapum Dam event and have unfailingly worked with us in a collaborative and expe-ditious manner. Grant PUD generously has shared time and information in a period of great stress for their utility. Chelan PUD employees have risen to the occasion, put in long hours with unwavering dedication to provide value to our customer-owners. It’s a time of great stress but also great reward when I see what is being accomplished.

And, not lost in all of our efforts to respond to an immediate crisis situation is the fact that no impact on customer rates is expected due to the measures taken. Our customer-owners have the benefit of years of thoughtful planning with carefully crafted financial policies and power purchase contracts providing a mea-sure of financial protection. You can have confidence that not only is your investment in the PUD being protected, we also are working hard to save you money.

We commit to keeping you informed as conditions change. I hope you will tell me if there are ways to do an even better job of letting you know the information you want.

Why Wanapum Reservoir Drawdown Matters

to Chelan County PUD

After extensive engineering studies Rock Island Dam today is producing 90 percent of normal output

Because of collaboration, installation was completed in six weeks rather than the expected two-years it would typically take

Rocky Reach Dam has had minimal impacts from the Wanapum Dam response efforts

Above: Outreach with irrigators is helping to reduce impacts

Below: Intense effort underway to keep boat ramps accessible when river flows recede

At Rock Island Dam we anticipate

juvenile fish passage should also be as effective as during

more normal conditions.