Draft Columbia River System Environmental Impact Statement Released

Details

Published: Friday, 08 May 2020 21:58

Overview

In late February, the U.S. Army Corps of Engineers, Bureau of Reclamation and Bonneville Power Administration (co-lead agencies) released a draft Columbia River System Operations Environmental Impact Statement (CRSO EIS) on the long-term system operation and configurations of 14 Federal multiple purpose projects throughout the Columbia River Basin.

Nearly 5,000 pages long, the co-lead agencies characterized this effort as “… responding to the Opinion and Order from the U.S. District Court for the District of Oregon. The Opinion and Order states the EIS should evaluate how to ensure that the prospective management of the CRS [Columbia River System] is not likely to jeopardize the continued existence of any endangered or threatened species, or result in the destruction or adverse modification of designated critical habitat.”

The EIS focuses on the effects of flood risk management, water supply, hydropower generation, fish and wildlife, navigation, cultural resources, recreation and other purposes. As effects were considered, six alternatives for operation, maintenance and configuration of the CRS were developed for a 25-year time horizon.

With meeting multiple environmental, economic and cultural objectives desired by sovereigns and stakeholders at play, the co-lead agencies “sought to achieve a reasonable balance.” A preferred alternative was identified that co-lead agencies believe best strike a balance between objectives, competing river resource needs and co-lead agency mission requirements, including complying with environmental laws and regulations.

This article highlights factors, operations and actions called for in the preferred alternative that are specific to Grand Coulee Dam and Lake Roosevelt.

Lake Levels

Modeling suggests changes in streamflow coming into to Lake Roosevelt (inflow) to be small, typically within 1 percent. Some of this is the result of recommendations for changes in operations at Libby and Hungry Horse dams.

Modeling also suggests the timing of inflow will occur earlier in the spring and summer due to earlier melting of snowpack induced by climate change. By the 2030s, the spring freshet peaks could occur one to two weeks earlier. This also leads to projections that inflows in late summer and early fall will be less.

Figure A shows differences in current operations vs. the preferred alternative in dry, average and wet years. In wet years (20% of the time), lake levels would be reduced in January and February. In a median wet year, the lake would be 5 feet lower at the end of February. In May, modeling shows about 2 feet less draft in wet years due to operational changes. And in the September/October time frame, the lake will be about half a foot lower 40% of the years.

Operational changes

Operational changes include:

• Establish a planned draft rate (how much the lake level would be reduced) of 0.8 feet per day. This would reduce the risk of erosion along the shoreline and may reduce spill in some years. This is proposed to support reducing the lake being lowered up to an additional 5 feet by the end of February in wet years. This would not change the limit of reducing lake levels no more than 1.5 feet per day, which typically occurs by April 30th to meet maximum flood risk management needs.
• Changes to the procedure for determining flood risk management drafts (how much lake levels are reduced to avoid downstream flooding). One objective is to keep lake elevation above 1,222.7 feet for irrigation pump efficiency. Another objective is to be able to flexibly respond to “trapped” storage in an upstream CSR reservoir.
• Existing lake level reductions to support Odessa Subarea irrigation, improve municipal and industrial water supply and enhance downstream flows for fish are unchanged. Currently, by the end of August this results in the lake being lowered an additional 1.0 foot in non-drought years and up to 1.8 feet in drought years.
• Timing of water delivery to the Odessa Subarea would be based on demand (when the water is needed) rather than the current September/October delivery schedule. Further, up to 45,000 acre-feet of additional water, based on demand, could be pumped to support the irrigation season (March to October). Reclamation would make the downstream effect of this neutral by releasing up to 0.25 feet of stored water downstream in the spring period.
• The current Lake Roosevelt minimum refill elevation of 1,283 feet at the end of September would be changed to the end of October. This provides more operational flexibility for power generation and supporting downstream flows for fish. However, this change may negatively impact the spawning success of kokanee, burbot and redband rainbow trout in Lake Roosevelt.

Fish

• In 2019, Bonneville funded a 3-year study to determine if changing the minimum refill elevation from the end of September to the end of October would impact resident fish access to spawning habitat. If it does, the co-lead agencies would supplement spawning habitat at locations along reservoir and tributaries (up to 100 acres).

• Changes in hydro operations at Libby Dam may have an adverse downstream effect on the presence of invasive species such as Northern Pike and flowering rush in Lake Roosevelt. The draft EIS indicates an invasive species management plan will be developed to address this issue.

• Water retention time (how fast water moves through the lake system) will be affected by proposed changes to lake elevations and the timing of inflow. This can lead to changes in entrainment risk (fish passing through Grand Coulee Dam), food source reductions and the timing for release of rainbow trout from net pens. Possible adverse effects in wet years were described as “minor,” and in certain scenarios “beneficial” in dry years.

Facilities and recreation

• Changes in lake elevations would result in decreased boat ramp accessibility in September and October but increases in accessibility in May and June.

• The boat ramp at the Gifford-Inchelium Ferry would be extended. This would mitigate the impact of earlier and longer lake level reductions that would otherwise make the ferry unavailable approximately four additional days a year.

Grand Coulee Dam

• Existing plans and ongoing actions to overhaul the third powerplant, modernize power-generating units in the left and right powerhouses, and modernize the John W. Keys III Pump-Generating Plant are identified and incorporated. The preferred alternative also supports expediting the maintenance schedule for the power plants and spillways.

Water Quality

• Operational changes are expected to have a minimal effect on water temperature, total dissolved gas, turbidity, or sediment quality.

What wasn’t considered and financing

Reintroduction of salmon above Grand Coulee Dam was not considered. Co-lead agencies pointed to data gaps and a need for a decision-making framework before reintroduction could be included in an EIS. The draft EIS is also distinct from the Columbia River Treaty (CRT) negotiations. For the EIS, 2016 CRT-related operations were applied.

If either reintroduction or CRT results in significant changes to river management, it’s not clear how or whether a finalized EIS would be modified.

Implementation of the preferred alternative is not expected to significantly change costs for operating the Columbia River System. Annual construction costs are estimated to increase by $4 million, capital costs would be the same, and fish and wildlife mitigation costs could decrease by as much as $41 million or increase by $6 million.

Next steps

The public comment period ended April 13th. Co-agencies will integrate comments into the final EIS, which is expected in summer 2020. A record of decision documenting final recommended actions is scheduled for September 2020.

At that time, NOAA will determine in a biological opinion if the preferred alternative for dam operations complies with the Endangered Species Act and adequately protects listed species, including orcas and salmon.

If past is prologue, some combination of state, tribal, fishing and conservation interests will challenge the resulting biological opinion. Past challenges have been based on requirements of the Endangered Species Act to protect salmon. These challenges have previously been successful.