Water trade-off bolsters rivers

Bend Bulletin article on the evaluation of the Deschutes Groundwater Mitigation Program.

SALEM — The straws are drilled deep underground, sucking more water to satisfy the thirst of development across Central Oregon. Yet at the same time, there’s more water flowing down the Deschutes River during the dry summer months when once it ran low.

In short, the state’s first water trade-off system — devised in 2001 — is working largely as promised.

The findings come from the first formal evaluation of the Deschutes Groundwater Mitigation Program, a water rights transfer system authorized by the Legislature in 2001 to meet seemingly conflicting goals: supply the region’s rapid growth, but also protect rivers.

“I think it’s working quite well from a stream flow standpoint,” said Kyle Gorman, a Bend-based watermaster for the Oregon Water Resources Department. “You can physically see a difference in the river flow in the summertime due to mitigation water in there.”

The future of development in Central Oregon hinges on the availability of water, but there isn’t any more of it available in the Deschutes River system, which is already fully tapped through long-standing water rights dating back more than a century.

Preserving the river basin
Instead of diverting water from rivers, Central Oregon resort developers and cities drilled wells — until a federal study in the 1990s showed that if you pump more groundwater, it will hurt flows in the protected Lower Deschutes.
That put a halt to new groundwater permits for four years, from 1998 to 2002, when the mitigation plan went into effect.

The system has a simple bottom line: New wells are allowed, but for every gallon of groundwater that’s pumped, a gallon of water must be routed back into the spiderweb of rivers that cross the Central Oregon High Desert.
How it works is farmers who own the rights to water in the Deschutes River or its tributaries either sell or lease those rights, and the water is left in the river instead of going into fields.

In exchange, the same volume of groundwater can be pumped from wells, year-round.

The mitigation “credits” and leased water rights are managed through a “bank” that’s run by the nonprofit Deschutes River Conservancy.

The mitigation plan covers the entire Deschutes River Basin, a 10,700-square-mile geologic bowl that funnels water northward — both in rivers and underground — along the east flank of the Cascades, from La Pine and Prineville to Lake Billy Chinook and then to the Columbia River.

The five-year analysis by the Oregon Water Resources Department shows that rivers are fuller as a result of the mitigation program.
And in some places, the levels are visibly higher, such as the Middle Deschutes just north of Bend.

Overall stream flows have climbed by 4.3 percent in that section of river, the state says.

The difference in the Middle Deschutes is dramatic during the summer: Water levels in that stretch have increased by roughly 45 percent, compared to the average from 1966 to 1995.

Meanwhile, the state has allowed new wells that are pumping a combined 84 cubic feet per second. That’s 42 percent of a cap of 200 cfs that was set for the mitigation program. A cubic foot of water per second translates to about 449 gallons per minute.

But there’s much more demand for water in Central Oregon. The stack of applications for new wells exceeds that 200 cfs cap, according to the Water Resources Department. Among those waiting in line are proposed destination resorts and cities that want to secure water for long-term population growth.
And that sets up the next political debate: when — and if — that cap should be raised.

Differing views
The new data from the report were presented in February to the state’s Water Resources Board, and members of that panel opted to not make any changes to the cap. The report goes next to the 2009 Legislature, which is scheduled to do its own review of the program and will likely hear conflicting reviews.

Tod Heisler, executive director of the Deschutes River Conservancy, said the mitigation program has paved the way for projects to restore streams throughout the Deschutes basin, while also allowing for economic development.  “The laws of physics say that if you take water out of the ground, it will have an impact elsewhere in the system,” he said. “We’re all basically working for the public good, whether it’s drinking water for people or water for fish and wildlife,” he said.

The mitigation work is just one part of efforts to conserve water and improve rivers in the basin, he said. At the same time, the orderly banking and leasing program — combined with the allowance of new wells — has helped avoid what would have been bidding wars by cities and developers for existing water rights, he said.
“It’s doing good things. Is it the panacea? I don’t know, but it is a good program and without it we would be much worse off.”
So far, there has been more than enough water kept in rivers to offset the additional groundwater pumping, the report says.
However, much of that water in-stream is being leased temporarily — and contracts will need to be renewed at some point. So the future is not certain, particularly as demand for water continues to rise.
Conservation groups argue the overall annual increase in water volume in rivers is a deceptive statistic, because it masks the fact that river levels have dropped slightly during the key spring spawning season.
That dynamic was raised in 2001 but didn’t stop lawmakers from initially approving the mitigation plan.
In addition, when the conservation group WaterWatch of Oregon sued to block the plan, the 2005 Legislature passed a bill — shepherded by state Sen. Ben Westlund, D-Tumalo — that allowed the mitigation efforts to continue.
Conservation groups intend to renew their concerns to the 2009 Legislature.
Their hope: require that water be returned to rivers at the same time it is being pumped, and near where it is being pumped, said Kimberley Priestley, assistant director of WaterWatch.
“Overall, we can say that during the irrigation season (the mitigation plan) is largely working in terms of impacts to the Deschutes,” she said. “It’s outside the irrigation season that it’s not working.”
The new water rights being leased and sold to satisfy the mitigation requirement are seasonal, which means they only result in additional volume in the river in the agricultural growing season.
During the winter, water isn’t diverted from the river system in canals, so the flow is robust.
However, there will be less water percolating from springs to augment that winter flow, she said.
To date, the difference is small but measurable.
Just below the Pelton Dam on Lake Billy Chinook, the river volume is now about one-third of a percent less than the historical average during winter months.
But the fear is the disparity will grow as additional permits are approved, Priestley said.
With that in mind, WaterWatch argues the state should not make any decision about expanding the cap on groundwater pumping past the 200 cfs until that threshold has been reached — and then the impact to rivers at that level is studied.
Watermaster Gorman said the only way the mitigation program can work is to shift irrigation water from seasonal water rights, and to keep the water in rivers.
Still, he said, the state is aware of concerns about declining flows in some parts of the year.
“We are looking into ways of improving wintertime flow,” he said.
One possible solution may be to release water from dams such as Crane Prairie and Crescent Lake in the winter to augment the water already in the river, he said.
The largest applicants who are waiting for approval to start drilling wells — with applications seeking between 5 and 10 cfs — are cities and resort developers, he said.