Managing the dams in the Pacific Northwest’s
Columbia River Basin,
the nation’s largest hydropower system, is an intricate balancing act.
Reservoirs must continually be emptied to avoid flooding and refilled to drive
the turbines that generate electricity. Complicating matters is the need to
accommodate numerous contracts and mandates on power generation, flood risks,
irrigation and other factors. And of course, there’s the fish.
Making matters worse, anticipated climate change is poised
to throw a monkey wrench into the planning as mountain snow cover (and its
associated spring runoff) is expected to change significantly throughout this
century.
Some new thinking is about to be applied to the problem.
This week, the science news Website ScienceDaily
reports that researchers at the University
of Washington and U.S. Army Corps of Engineers have refined
and optimized a water management model, taking the expected changes into
account.
In a paper published
in the Journal
of Water Resources Planning and Management, the researchers noted that
anticipated temperature changes for the region “will cause reduced spring snow
pack, earlier melt, earlier spring peak flow, and lower summer flow.”
And these changes are likely to disrupt the balance between flood
control and reservoir refill in existing reservoir systems.
Current water management systems do not and will not be able
to take the changes into account. The systems use historical stream-flow
records to gauge when to open and close the floodgates. According to
ScienceDaily, the University of Washington
and the Army Corps of Engineers researchers
“compared historical conditions with a scenario where temperatures are 2
degrees Celsius higher on average than today, a change expected in the Pacific
Northwest by the second half of this century. And they created a
computer program that uses long-term forecasts rather than historical records
to recalculate when to begin filling and emptying the major storage reservoirs
in the Columbia River
basin in a warmer climate.”
Based on the refinements, the researchers believe, for some
locations, due to the reduced snowpack and lower spring peak flows, water managers
will be able to refill reservoirs a month earlier in the spring without fear of
flooding. This could help supply more hydropower in the summer, while also
providing more water storage for other purposes, according to the researchers.
Specifically, “computer simulations showed that switching to
the new management system under a warmer future climate would lessen summer
losses in hydropower due to climate change by about a quarter,” according to published
reports on the research. It would also bolster flows for fish by filling
reservoirs more reliably.
Essentially, what the researchers have done is develop
a tool that might one day be used by water managers in the Pacific Northwest to address the changes from anticipated rising
regional temperatures. ScienceDaily noted that it will be years before the
current management practices are formally changed, but this work is a first
step in that direction.
