The Federal Energy Regulatory Commission (FERC) relicensing process for several of Idaho Power’s 15 FERC-licensed hydroelectric projects has spawned fresh thinking about how to manage fish passage and water quality. Nearly 60 years after an agreement to change its mitigation program to a hatchery program for Chinook salmon and steelhead trout, Idaho Power is finding new approaches to keep populations healthy and address issues like high temperatures, dissolved oxygen (DO), dissolved gas, and connectivity. We speak with Jim Chandler, the environmental manager at Idaho Power, to learn more.
Hydro Leader: Please tell us about your background and how you came to be in your current position.
Jim Chandler: I manage the fish and water quality programs in the Environmental Affairs Department at Idaho Power. I started with Idaho Power 32 years ago, right out of graduate school. I worked as a fish biologist, and as time progressed, I moved into a supervisory role, implementing various fishery programs. Recently, the water quality and fish teams were put in one group, so now I focus on managing our fish and water quality programs.
Hydro Leader: Please tell us about Idaho Power.
Jim Chandler: Idaho Power has a large service territory, mostly covering southern Idaho and a portion of eastern Oregon. We have 17 hydroelectric projects, 12 of which are along the mainstem Snake River. Hydroelectricity usually accounts for more than 40 percent of our generation portfolio. The department’s primary focus is to work on the licensing, compliance, and relicensing of those hydro projects, 15 of which are licensed by FERC. Most of those projects have undergone some level of relicensing work, and we are currently in the process of relicensing two: American Falls and our largest, the Hells Canyon Complex (HCC), which includes Brownlee, Oxbow, and Hells Canyon Dams.
Hydro Leader: Please tell us about your fish hatchery program.
Jim Chandler: Our hatchery program started in the early 1960s. When plans were finalized to move ahead with the construction of Brownlee Reservoir and Dam, the uppermost and largest of our three HCC reservoirs, there were fall Chinook salmon, spring Chinook salmon, and steelhead spawning and rearing above the Brownlee Dam site. The initial plan was to pass those fish above Brownlee and collect juveniles during their downstream migration in a big net collection system in Brownlee Reservoir, and the net was built upon the completion of Brownlee Dam in 1958. However, it became clear that although trapping adults below the dam and transporting them above it to let them spawn naturally was successful, the downstream migration collection of juveniles did not work. Those small juvenile fish could not migrate through a large reservoir like Brownlee. They rely on water currents to orient them and help them migrate downstream, and in a reservoir the size of Brownlee, they were disoriented and were not able to find their way to the collection facility in sufficient numbers to sustain and maintain adult returns.
A decision was made in 1964 to transition the passage program to a hatchery program. We developed four Idaho Power hatcheries, which primarily rear steelhead and spring Chinook salmon. As we progressed with implementing the hatchery program in the mid‑1970s, salmon and steelhead numbers were declining precipitously in the Northwest as other hydro projects were being developed in the region. There was concern on the part of the States of Idaho, Oregon, and Washington; the National Marine Fishery Service (NMFS); and tribes about whether the hatchery production was sufficient to mitigate the losses associated with the construction of the HCC. In 1980, Idaho Power reached a settlement agreement with the three states and the NMFS that defined a fish production level that our hatchery facilities needed to meet. That formed the basis of today’s hatchery program. Today, our hatchery program produces about 1.8 million steelhead, 3 million spring Chinook, 1 million summer Chinook, and 1 million fall Chinook every year. Those fish are released in various places throughout the Snake River basin to mitigate the loss of fish above the HCC. The primary goal is to provide fisheries for the tribes and the three states affected by the lost production above the HCC. We fund the hatcheries, and the Idaho Department of Fish and Game operates them. The adult fish that return as a result of those fish releases are comanaged through agreements among the states and tribes.
Hydro Leader: Are there also passage structures, such as fish ladders, on some of those Snake River dams?
Jim Chandler: Because passage above the HCC proved to be infeasible, the fish managers decided not to release fish above the dams. Rather, all the fish are released in areas accessible from below our lowermost dam, including the Salmon River basin, which is a tributary of the Snake River. The fisheries that are created by our hatchery program include those in the Columbia River and the Snake basin below our lowermost dam. There is an adult fish ladder that leads to a fish trap at the base of Hells Canyon Dam, but that is the only active passage structure we have at any of our mainstem facilities. It is used primarily to capture salmon and steelhead as they migrate upstream to provide brood stock for the hatchery program. There are plans, through an agreement with the U.S. Fish and Wildlife Service, to modify this trap to also allow for the capture of bull trout, a listed species under the Endangered Species Act, as a means of upstream passage for this migratory fish.
Upstream of Hells Canyon Dam, we are trying to restore connectivity for white sturgeon. The lack of connectivity has been an issue at our middle Snake River projects, specifically C.J. Strike and Bliss Dams, which are in an area with one of the more productive white sturgeon populations. Before the construction of C.J. Strike Dam, it is likely that the fish populations we currently see below the dam site migrated above it. Currently, there is no passage structure at that dam, nor is much understood about the passage requirements for large white sturgeon. One of the things we currently do to mitigate the lack of passage is to capture spawning adults below C.J. Strike Dam and transport them above it to allow them to spawn naturally in that reach. Our other primary mitigation activity is another hatchery program—our White Sturgeon Conservation Hatchery.
Hydro Leader: What are the main issues for fish presented by your infrastructure and dams?
Jim Chandler: The primary issues relate to water quality— specifically temperatures, DO, and total dissolved gas. We have worked on temperature downstream of Hells Canyon Dam during the fall Chinook spawning period. We’ve also worked with the Oregon and Idaho Departments of Environmental Quality (DEQs) to come up with measures that would offset or mitigate the issues related to temperature and DO at Brownlee Reservoir and total dissolved gas at all our projects.
In terms of temperature, the main issue was that the water being passed is warmer than the standard at the initiation of the fall Chinook spawning period downstream of Hells Canyon Dam. Because the temperature effects are minimal for this short period of time, Idaho Power and the states developed a temperature offset program rather than trying to meet the spawning temperature requirement directly below Hells Canyon Dam. This thermal reduction was defined in units of energy or kilocalories of solar input. The goal is to reduce the level of solar radiation on the upstream waters flowing into the HCC to offset the difference between current conditions and the spawning standard. Modeling has shown that if summer water temperatures upstream of the complex can be cooled, we can meet the standard downstream.
Idaho Power’s Snake River Stewardship Program involves working in the mainstem Snake above Brownlee Reservoir and in several of the tributaries above the HCC to reduce solar input into those waters to meet the offset goal. We have planted about 20 acres of riparian vegetation to create shade along three tributaries. We have also worked in some of the low-gradient, broad, shallow reaches of the mainstem Snake River to reduce the solar input on the surface of the water by expanding the floodplain around islands. To date, we have created about 24 acres of floodplain on two island complexes. Enlarging islands also creates channels that are narrower, deeper, and a little faster in some sections, enhancing aquatic habitats. This is a 30‑year program based on the idea that improving inflows into the complex will also improve the outflow.
We are working on some of the bigger drivers that contribute to low-DO conditions, such as phosphorus loads flowing into the HCC. Upstream of the project, we have a program to help farmers convert furrow and flood irrigation to sprinkler irrigation, which greatly reduces the amount of sediment and nutrients coming into the river. This equates to better DO levels in the water. We’ve seen improvements over time, not only in the inflows to Brownlee Reservoir but in the outflows and within the reservoir itself. We have also installed distributed aeration systems in the turbine runners at Brownlee Dam. They draw atmospheric air down through the turbine blades and infuse it into the water to elevate the oxygen levels of the water coming out of the plant. We run the aeration system during the low-DO periods of the summer months.
We are also in the process of designing and modeling flow deflectors that will change the spill characteristics from a plunge to more of a flow across the surface. This reduces the total dissolved gas levels below the dams. Upon receipt of the Hells Canyon license, we will be required to install flow deflectors at each of the HCC dams. We are designing those now.
Hydro Leader: Have your efforts had measurable effects on water quality?
Jim Chandler: We’re still early in the implementation of the DO program, but between our actions and those of others, we are already seeing significant improvements to DO throughout the HCC. The flow deflectors I mentioned will be constructed after the issuance of the Hells Canyon license. The Snake River Stewardship Program is a 30‑year program, so we don’t expect to have measurable results soon.
Hydro Leader: Do you also try to release colder water from your reservoirs in order to reduce the temperature downstream?
Jim Chandler: Yes and no. We have discussed that as part of our consultations with various agencies during the Hells Canyon licensing process and during our work on our 401 water quality certifications with the DEQs. There was a desire by many to have selective withdrawals or to create a structure to release colder water from Brownlee Reservoir. Brownlee Reservoir is a large storage reservoir, and it does stratify by temperature. It has a significant volume of colder water in its deeper sections, and there has been interest in accessing that colder water and passing it downstream to help meet temperature standards. That idea was evaluated for some time, but the colder water in Brownlee Reservoir has very low DO levels and contains toxins, such as methyl mercury. The worry was that passing that colder water could create more problems downstream. Those considerations are part of why we moved our attention upstream of the HCC and initiated the Snake River Stewardship Program.
The stewardship program will not necessarily result in us meeting the fall Chinook temperature standard right away, but fall Chinook are actually doing relatively well below Hells Canyon Dam. In fact, their numbers have improved substantially over the course of the last 30 years. Much of this improvement can be attributed to the hatchery program as well as special operations at Hells Canyon Dam to protect spawning and rearing habitats. Meeting the temperature spawning standard is not an immediate need or an emergency relative to factors limiting the population, which is why we are addressing some of the longer-term issues above the HCC rather than trying to release colder water from Brownlee Reservoir now.
That said, our 401 water quality certifications do include a condition related to a temperature threshold of 16.5 degrees Celsius, above which fall Chinook do not do well during the initiating of the spawning season. To address that, we are developing a temperature forecast model to predict whether temperatures at the start of the spawning period would exceed that level. If so, we may draw down Brownlee Reservoir to lower elevations in the fall than we otherwise would so that cooler water can come in and more quickly pass through the reservoir. Our 401 water quality certification also states that if we exceed a 16.5°C threshold for 3 years in a row, we will need alternative measures to the stewardship program. That could involve revisiting the idea of accessing the colder, deeper water in Brownlee with some type of structure.
Hydro Leader: What is your vision for the future?
Jim Chandler: Idaho Power is fully invested in the Snake River. We’d like to see healthy fish and good water quality throughout the system. Through the programs we have been discussing, Idaho Power can actively improve conditions while we continue to provide clean hydropower. We plan to implement the programs that we have talked about at full scale. Many of these water quality programs and measures will be fully implemented when we receive the Hells Canyon license. That’s anticipated to occur within the next couple of years. We will also initiate several programs that we haven’t talked about, including bull trout passage at the HCC; evaluate salmon and steelhead reintroduction; and consider the possibility of increasing passage at Hells Canyon Dam over the long term. There is a lot in play that I think will significantly benefit aquatic resources over the long term.