The U.S. Army Corps of Engineers has conducted a “spring pulse” event at Kinzua Dam on the Allegheny River in Pennsylvania to help improve the downstream ecosystem.
Spring pulses are natural phenomena that typically occur in temperate climates and during early spring. As the weather warms up, rivers and tributaries receive more precipitation and runoff water, sending a cue to aquatic species and other parts of the ecosystem by moving sediments and nutrients. This movement encourages vegetation growth and provides post-winter habitats for animals. For instance, the paddlefish uses the spring pulse as a cue to spawn.
Millions of gallons of water rushed out of Kinzua Dam every minute for eight hours straight, raising the Allegheny River by almost 2 feet. This water release event was seven years in the making, a “perfect storm” of conditions that allowed water quality experts to replicate a spring pulse, the Corps said.
Kinzua Dam controls water flow to reduce flooding. The dam has prevented more than $1.3 billion in flood damages since its construction in 1965, the Corps said. But with recent heavy rains, the Water Quality team pounced on an opportunity to simulate a spring pulse. The river had not seen a natural spring pulse since Kinzua Dam was constructed in 1965, the Corps said.
“We’re normally fairly restricted in how water is released from the dam, so we don’t see the normal pulses rivers see,” said Andi Fitzgibbon, a biologist with the Corps’ Pittsburgh District’s Water Quality team.
To generate the pulse, operators increased the dam’s outflow from 9,000 cubic feet per second (cfs) to 15,000 cfs for eight hours. That resulted in 3.2 billion gallons of water released into the river. The district’s water management team modeled the operation to ensure the artificial pulse would not impact the reservoir’s summer pool or cause flooding.
To test the effects of the pulse, the Water Quality team collected water and tested samples downriver. They threw buckets into the river, poured samples into bottles and cylinders, and tested the samples using machines on the back of their trucks.
Simulating the spring pulse is a significant milestone for the district. Kinzua Dam operates according to congressionally approved protocols based on flooding, navigational and environmental conditions. However, because the dam holds back reservoir water, it prevents spring pulses from occurring naturally.
Organizing the spring pulse took more than seven years to coordinate because it required the reservoir to meet specific water conditions and historical flow regimes without sacrificing its operational responsibilities.
Carl Nim, a biologist with the Water Quality team, said organizing the pulse required coordination and quick response. For example, the Water Quality team knew they could release the spring pulse when heavy rains hit, raising the reservoir level 2 feet above the summer pool months ahead of schedule. That meant the reservoir was suddenly holding back a lot more water that the team could use for the pulse.
In addition, during the spring pulse, PhD students from the University of Pittsburgh conducted their own water-sampling tests near Kinzua Dam. “Without the pulse or spring events like it, outdoor recreation activities will be severely impacted, and these beautiful ecosystems could deteriorate,” said Abby Yancy, a PhD student at the university. “The pulse is important for many beloved sensitive aquatic and terrestrial organisms like plants, fish mussels.”
For Nim, the initiative is an exciting step for the Corps’ role in improving water quality for the region. The Water Quality team travels weekly across the district’s 26,000-square-mile span to collect samples to assess “bio-indicators” that represent ecological quality. “We collect a bunch of different parameters,” said Nim. “So we’d look at pH, acidity, alkalinity, turbidity, dissolved oxygen, specific conductivity, nutrients, as well as metals. Those just scratch the surface of describing what we look at.”
The collected data is used to make reservoir-management decisions, such as how much water to release to improve downstream water quality and keep the waterways clean. One of the mantras Nim says to teach others about how water quality works is “dilution is the solution to pollution.”
The dam is also part of the 451.8-MW Kinzua (also called Seneca) Pumped-Storage project, owned by Seneca Generation LLC.
