Ecosystem Cascade of Effects & Hydrology

Cascade of FRE Facility Ecosystem Effects Technical Memo

Hydrology Memo 1: Observed and Predicted Flows

Hydrology Memo 2: Hydrology and Climate Change 

This series of reports examines how the dam would set in motion a much larger “cascade” of impacts than estimated in the DEIS. Among the key findings of these analyses are: the dam would trigger into operation more frequently and impoundment of water behind a temporary reservoir would last longer; reductions to groundwater recharge are underestimated; landslides and hillslope erosion from operation of the temporary reservoir, and therefore delivery of downstream fine sediment, are drastically underestimated.

Fine sediment is known to smother and kill salmon eggs. Groundwater storage is critical to sustain river flows, especially in summer when low water and high temperatures can create river conditions lethal to fish. Groundwater recharge is also important to the health of downstream wetlands, side channels and other habitats for salmon and other fish and wildlife. (Find more information on underestimated impacts of landslides in the geology section below).

Geology Technical Review

Earth Discipline Report – Geology Technical Analyses Review

A major finding of this report is that the DEIS estimate of 840,500 cubic yards of sediment from landslides over the life of the project is drastically underestimated. Actual sediment volumes would be much higher, potentially as high as 16,000,000 cubic yards. A significant portion of that landslide sediment would be fine-grained and result in reduced salmonid egg survival.

The DEIS’ low estimate of sediment volumes also means the potential threat to public safety is underestimated. Landslides can deliver debris and mass into a filled reservoir generating large displacement waves that can overtop a dam creating life-threatening conditions downstream, damage infrastructure and affect the foundation stability of a dam.

Fish and Fisheries

Review of Impacts on Fish and Fisheries Technical Report

Salmon Population Modelling Technical Report

These two reports examine how the impacts to salmon and steelhead in the DEIS were underestimated and the role flawed fish modelling played in under-reported impacts. The analyses also delve into key uncertainties about the dam’s potential impacts. For example, there are major uncertainties about how habitat conditions above and below the dam during construction and operation would change, including:

• How fast will habitat recover from an FRE facility closure event?

• What will habitat above the FRE facility look like through time?

• How will downstream conditions change?

• Will fish recolonize habitat after an FRE facility event, and if so, how quickly?

The analyses put emphasis on spring Chinook describing the special biological, ecological, and cultural significance of the species to the Quinault people, its current status, likely impacts of the proposed project and the potential for being listed as threatened or endangered under the Endangered Species Act (ESA). While the DEIS does address certain likely impacts on spring Chinook, it does not adequately account for the importance of this population either in the Chehalis Basin or within the Washington coastal region
and beyond.

Economic Review

Economics & Socioeconomic Analysis Review

This report looks at major deficiencies in economic analyses in the DEIS, which does not include a cost-benefit analysis. Economic and social impacts of dam construction, operation and potential catastrophic failure are not developed or assessed. Although the DEIS states that “significant adverse impacts” will occur, no economic analysis or impact analysis has been conducted to understand the economic or social implications of any change in abundance of Chehalis Basin salmon.

The DEIS fails to assess the considerable economic consequences of impacts to natural resources, including the ecosystem services they provide. A recent ecosystem services valuation conducted for the Chehalis Basin indicates that the Basin’s natural capital provides an estimated minimum of $1.1 billion to upwards of $15.7 billion in ecosystem service benefits annually.

Alternative

LOCAL ACTIONS ALTERNATIVE TECHNICAL ANALYSES REVIEW

This analysis looks at how the DEIS failed to provide comprehensive flood risk evaluation for the proposed project target area, insufficient analysis of the Local Actions Alternative and explores key elements needed for development of a viable Local Actions Program. The analysis describes the limited flood damage reduction benefits of the proposed dam and offers examples of area-specific strategies for applying Local Actions Program elements in the Chehalis Basin.

The flood damage reduction analysis presented in the DEIS contradicts sound standards of flood risk management practices to comprehensively assess all flood risks to an area, and then develop solution options to address those risks.

The Chehalis-Centralia area experiences regular damaging flooding from several local creeks that flow through the two cities, most notably China Creek, Salzer Creek, Coal Creek and Dillenbaugh Creek, but nothing in the DEIS acknowledges the flood risks posed by local creeks. The DEIS has inappropriately focused on flooding from a single source within the Chehalis Basin – the upper basin above the Town of Pe Ell – when it is well known that damaging floods originate from numerous sources within the Chehalis Basin, including the South Fork Chehalis, Newaukum, Skookumchuck, and Satsop watersheds.

The failure to adequately evaluate different geographic sources of flooding and a range of storm events compounds the DEIS’s failure to actually meet its stated purpose and objectives.

The Local Actions Alternative fails to meaningfully develop elements such as buyouts, relocation and local flood protection measures, fails to describe how and when these elements would be accomplished, and fails to objectively analyze how such elements could achieve the goals and purpose stated in the DEIS, even though data is available to do so.

A viable Local Actions Program could be developed with enough specificity to enable comparison of benefits and impacts against the proposed project, and with enough specificity to enable evaluation of implementation feasibility and community support. A viable Local Actions Program offers a means of reducing local flood damages originating from streams and rivers other than the Upper Chehalis, providing more comprehensive relief in the Centralia-Chehalis and throughout the entire Chehalis Basin.

A much more detailed Local Actions Program is best suited to address the range of flood problems and geographic flooding scenarios not considered in the DEIS, and is more in keeping with legislative direction to reduce flood damage throughout the entire Chehalis Basin.