Conservationists comment on Eightmile DEIS

June 10, 2023 

The "cart-before-horse" approach to designing a dam before knowing how much water it can hold has drawn broad criticism.

It is a recurring theme in responses by conservationists to the Washington Department of Ecology's draft environmental impact statement ("DEIS") for a replacement dam in the Alpine Lakes Wilderness. Ecology, they claim, cannot design a dam at Eightmile Lake without first deciding how much water the Icicle Peshastin Irrigation District still legally owns.

Conservationists acknowledge that the irrigation district has a grandfathered water right that preceded creation of the Alpine Lakes Wilderness, but the extent of that right, they insist, has been partly relinquished through decades of non-use. Many commenters also acknowledge or support repair or replacement of the dam to meet safety standards.

For its part, the irrigation district acknowledges that for irrigation purposes it only needs 1,400 acre-feet annually. No one seems to have any quarrel with it using that much water, but the design alternatives in the DEIS call for dams that could store and use much more – anywhere from 1,698 to 2,000 acre-feet.

As one commenter rhetorically asks: "Why is Ecology reluctant to examine the District's water rights during this EIS process when it clearly has the option – or obligation – to do so?"

Several groups complained that they have raised concerns for many years about relinquishment. They reminded Ecology that it previously had promised to determine the extent of the irrigation district's water right, which it now admits it has not done. As one group says, "We expected this determination prior to this Draft EIS. However, in the subsequent years we have not seen such a determination and there is no information regarding its progress."

On this point, another adds: "The EIS is at best, incomplete, but often silent on these matters."

Others complain that the DEIS fails to define the scope and extent of the irrigation district's "existing private rights" under the Wilderness Act. Because Eightmile Lake is within the Alpine Lakes Wilderness, any dam must comply with that law. The Wilderness Act prohibits structures or installations for anything other than to maintain existing private rights.

Several commenters also complained about a new methodology suggested in the DEIS for measuring water rights – something called multi-fill analysis. Under it, the irrigation district could count not only the water it stored over winter, but also water that flowed through Eightmile Lake during summer rain and runoff. This new analysis had not been publicly disclosed before release of the DEIS. As one commenter said, "It is not clear if this multi-fill analysis is an acceptable way to measure a water right ..." That commenter complained that the DEIS appeared to switch back and forth between multi-fill and the traditional single-fill approach.

If Ecology adopts and applies this newly-introduced multi-fill analysis consistently, that might over-shadow previous questions about relinquishment of some water rights, but it would raise new questions about the storage capacity needed for any replacement dam. As one group explains: "If Multi-Fill Analysis is correct and IPID [the irrigation district] has not relinquished any of its water, then IPID has been using its full water right through a multi-fill process with only 1,600 acre-feet of draw down." Even the most modest of the three proposed designs for a dam would exceed that and would "allow for more storage than the dam historically held."

The next move is Ecology's. It will need some time to digest and address some substantial and pointed comments. Previously, Ecology predicted that it might be able to release its final EIS later this year. That seems optimistic.