A Hermiston company's work on the Umatilla Basin Aquifer Recovery Project is reaching a milestone.
As outlined in SB 1069, the project has been researching infrastructure and possible recharge sites within the Umatilla Basin's critical groundwater areas to divert water from the Umatilla and Columbia Rivers during winter months into the recharge areas.
"We're between a third and half way to being able to put it all together," commented Said Amali, with IRZ, the Hermiston company completing the study. "We've achieved a milestone on the project."
He and other hydrologists identified three potential recharge areas at a stakeholder's meeting Wednesday morning. In addition, the group has made strides in identifying basalt zones and available infrastructure. By the next meeting, Amali said the group will be moving onto the next stage - getting into the nitty gritty details of the project.
In his presentation to stakeholders, Amali showed three potential sites: Echo Meadows (a current recharge site), County Line (which has a center sitting just northwest of the Interstate 84-Interstate 82 interchange and extends in a long oval east past the Umatilla River and equally as far west and Stage Gulch northeast of Echo Meadows.
For the most part, Amali said Echo Meadows and Stage Gulch would primarily act as treatment sites for water, while County Line would be a good place for treatment and storage.
At County Line, Amali showed two graphs overlaying each other. One showed the water height in wells since the 1950s. In the 1950s, it peaked at an elevation of about 505 feet, hit a low in the late 1970s of about 485 feet, raised in the 1980s back up to 505 feet, but dropped in recent years to about 495 feet.
"If you go to look at sort of an average elevation in these, it falls to about 495," Amali said, "compared to the pre-developement times, you're looking at more than a ten-foot rise that could still be achieved just to get back to those numbers."
The second graph showed total annual recharge put into the area since the late 1970s.
"What's interesting is that the trend in groundwater level very closely mimics the trend recharge. The more recharge, the more the well responds and comes up," Amali said. "For our project what that means is that there's enough hydraulic control over this, that a lot of that recharge water could be assumed to stay within the aquifer and not run off right away."
At Echo Meadows Amali showed his work over the past few months in finding the flow gradient across the area by looking at elevations of water in wells (which ranged from about 625 feet to 550 feet). In doing so, he was able to determine that most of the water comes in from the southeast corner, near the Westland Diversion, and moves northwest toward Stanfield Meadows and the Umatilla River. Some smaller input also comes from the northwest and southeast, but Amali said the flow is primarily northeast across the recharge area.
Amali also completed some basic geologic cross sections of all three areas by using data from the wells. In each case, he identified boundaries between underlying basalt and newer deposits from the rivers and Misoula Floods. For these recharge projects, Amali was looking for places where water could be stored in shallow aquifers, meaning between the underlying basalt and the surface.