Alternatives

The Final Environmental Impact Statement (EIS) documents the potential impacts and benefits, and ways to avoid or minimize impacts for construction and long-term management of the project alternatives.

After reviewing public comments on the Draft EIS, Enterprise Services made two substantive changes to the long-term management alternatives.

Before demolition of the 5^th Avenue Dam under the Estuary and Hybrid Alternatives, a new 5^th Avenue Bridge would be constructed to the south and connected to the roadway on either side of the waterbody. This would avoid long-term closure of the corridor, which was a key concern of project stakeholders.
The Hybrid Alternative was modified to include a groundwater-fed freshwater reflecting pool rather than a saltwater reflecting pool. With adaptive management, this would improve water quality over a saltwater reflecting pool.

A list of other substantive edits and clarifications made to the Final EIS and supporting discipline reports is provided in the Final EIS Supporting Materials.

EIS Supporting Chapter 2.0 describes how the alternatives were developed, summarizes each alternative in detail, and provides overviews of what would be required to construct each alternative. The project alternatives are summarized below.

The Final EIS identifies the Estuary Alternative as the Preferred Alternative. As documented in the Final EIS, estuary restoration best achieves project goals compared to the other alternatives considered, has the broadest stakeholder support, and provides other benefits to the natural and built environment.

Information on how the preferred alternative was identified is provided on the EIS Process page.

Under the Estuary Alternative, the 5^th Avenue Dam will be removed, and an approximately 500-foot opening will be established in its place. This will reintroduce tidal flows to the Capitol Lake – Deschutes Estuary, returning the area to estuarine conditions where saltwater from Budd Inlet will mix with freshwater from the Deschutes River.

Key elements of this alternative include:

Initial construction dredging in the Middle and North Basin channels
Establishment of shoreline habitat in the Middle and North Basins
New 5^th Avenue Bridge south of the existing 5^th Avenue Dam and Bridge, which would include a vehicle lane, bicycle lane, and sidewalks with dedicated recreational trail connection
Removal of the 5^th Avenue Dam
Boardwalks in the Middle and South Basins
Restoration of boating and fishing
Recurring maintenance dredging in West Bay
Implementation of a Habitat Enhancement Plan to maintain ecological functions

Learn more about the alternatives in EIS Supporting Chapter 2.0

An aerial overview of the Estuary Alternative, including colors, symbols and text to indicate the primary alternative components. The primary components shown on the graphic include: initial dredging in the Middle and North Basin channels; establishment of habitat areas in the Middle and North basins; Habitat Enhancement Plan to maintain ecological functions; boardwalks adjacent to ecological improvements in the south and middle basins; restoration of boating and fishing; a new 5th avenue pedestrian bridge; removal of the 5th Avenue Dam to improve water quality; and maintenance dredging in West Bay to remove accumulated sediment.

Under the Hybrid Alternative, the 5^th Avenue Dam would be removed, and an approximately 500-foot opening would be established in its place. Tidal flows would be returned to the western portion of the North Basin and to the Middle and South Basins. Within the North Basin, a retaining wall would be constructed to create an approximately 45-acre groundwater-fed, freshwater reflecting pool adjacent to Heritage Park.

Key elements of this alternative include:

Initial dredging in the North and Middle Basin channels
Establishment of shoreline habitat in the North and Middle Basins
New 5^th Avenue Bridge south of the existing 5^th Avenue Dam and Bridge, which would include a vehicle lake, bicycle lane, and sidewalks with dedicated recreational trail connection
A new reflecting pool and multimodal trail in the North Basin
Removal of the 5^th Avenue Dam
Boardwalks in the Middle and South Basins
Recurring maintenance dredging in West Bay
Restoration of boating and fishing
Implementation of a Habitat Enhancement Plan to maintain ecological functions
An Adaptive Management Plan to improve water quality in the reflecting pool

Learn more about the alternatives in EIS Supporting Chapter 2.0

An aerial overview of the Hybrid Alternative, including colors, symbols and text to indicate the primary alternative components. The primary components shown on the graphic include: initial dredging in the Middle and North Basin channels; establishment of habitat areas in the Middle and North basins; Habitat Enhancement Plan to maintain ecological functions; boardwalks adjacent to ecological improvements in the south and middle basins; restoration of boating and fishing; a new 5th avenue pedestrian bridge; removal of the 5th Avenue Dam to improve water quality; and maintenance dredging in West Bay to remove accumulated sediment. It also shows a multimodal trail on the retaining wall at the reflecting pool, and an adaptive management plan that would be needed for a freshwater reflecting pool (but not in a saltwater reflecting pool).

The Managed Lake Alternative would retain the 5^th Avenue Dam in its current configuration. The 5^th Avenue Dam would be overhauled to significantly extend the life of the structure. The existing reflecting pool within the North Basin would be maintained and active recreational use would be restored there.

Key elements of this alternative include:

Repair and maintenance of the 5^th Avenue Dam
Non-vehicular bridge south of the existing 5^th Avenue Bridge to provide a dedicated bicycle and pedestrian recreational trail connection
Adaptive Management Plan for water quality
Initial construction and recurring maintenance dredging in the North Basin only
Establishment of shoreline habitat in the Middle Basin
Transition of the Middle and South Basins to freshwater wetlands
Implementation of a Habitat Enhancement Plan to maintain ecological functions
Restoration of boating and fishing
Boardwalks in the Middle and South Basins

Learn more about the alternatives in EIS Supporting Chapter 2.0

An aerial overview of the Managed Lake Alternative, including colors, symbols and text to indicate the primary alternative components. The primary components shown on the graphic include: initial and maintenance dredging in the North Basin only; transition to freshwater wetlands in the South and Middle basins; Habitat Enhancement Plan to maintain ecological functions; boardwalks adjacent to ecological improvements in the south and middle basins; restoration of boating and fishing; adaptive management plan to improve water quality; and a new 5th avenue pedestrian bridge.

A No Action Alternative, which represents the most likely future expected in absence of implementing a long-term management project, was evaluated. This is a required element of an EIS under the State Environmental Policy Act. It provides a baseline against which the benefits, impacts, and costs associated with the action alternatives can be compared. The No Action Alternative does not meet project goals.

Learn more about the alternatives in EIS Supporting Chapter 2.0

Visual Simulations

In support of the visual resources analysis for the EIS, the project team prepared visual simulations from different locations in the Project Area. Locations for these simulations were selected in areas where the alternatives would be expected to have the highest potential for people to observe changes in visual character because of the project (i.e., public places—parks, public rights-of-way, or the Capitol Campus). These locations were selected because they represent the following:

Views experienced by a large number of visitors.
Locations where the changes caused by the project alternatives would be highly visible.
Locations that will also help the viewer understand the typical changes that would occur elsewhere in the Project Area as a result of the project alternatives.

The locations were also reviewed by the Community Sounding Board and then modified based on that feedback.

An aerial image that denotes the study area for Visual Resources. This includes areas in and around the Project Area. Key View Points (KVPs) are placed at the north end of the North Basin (Eastern Butte; KVP-NB-1), the North Overlook near on the Capitol Campus (KVP-NB-2), Marathon Park (KVP-NB-3), and at the Interpretive Center (KVP-MB-1).

Interpretive Center – KVP-MP-1

Estuary Alternative – High Tide

A visual simulation of the Estuary Alternative, looking north from the dock at the south end of the interpretive center. The visual simulation was generated to represent the potential views in the Middle Basin from the dock or boardwalks that would be constructed along the shoreline. The Middle Basin is full of water there is lush vegetated habitat along the shorelines.

Estuary Alternative – Mean Tide

Estuary Alternative – Low Tide

EASTERN WASHINGTON BUTTE – KVP-NB-1

Estuary Alternative – High Tide

A visual simulation of the Managed Lake, looking north from the dock at the south end of the interpretive center. The visual simulation was generated to represent the potential views in the Middle Basin from the dock or boardwalks that would be constructed along the shoreline. The Middle Basin is full of water there is lush green habitat along the shorelines.

Estuary Alternative – Mean Tide

A visual simulation of the Estuary Alternative, looking south from the Eastern Washington Butte in Heritage Park. The visual simulation was generated to represent the potential views across the North Basin, toward the Capitol Building. The North Basin is partially full of water and there is more visible vegetated habitat and some tide flats beginning to show.

Estuary Alternative – Low Tide

Hybrid – Low Tide

A visual simulation of the Hybrid Alternative, looking south from the Eastern Washington Butte in Heritage Park. The visual simulation was generated to represent the potential views across the North Basin, toward the Capitol Building. There is water in the North Basin and the barrier wall is visible in the distance.

Managed Lake

MARATHON PARK – KVP-NB-3

Hybrid Alternative – High Tide

A visual simulation of the Hybrid Alternative, looking east from Marathon Park. The visual simulation was generated to represent the potential views from the North Basin, toward the reflecting pool. The sheet pile barrier wall is a predominant feature of the visual landscape, across from the full water in the estuary.

Hybrid Alternative – Low Tide

NORTH OVERLOOK – KVP-NB-2

Estuary Alternative – High Tide

A visual simulation of the Estuary Alternative, looking north toward the North Basin and Budd Inlet. The visual simulation was generated to represent the potential viewshed from a North Overlook on the Washington State Capitol Campus. The North Basin is full of water with habitat areas showing on the eastern shoreline of the North Basin. Birds and new 5th Avenue Pedestrian and vehicle bridges can be seen in the distance.

Estuary Alternative – Mean Tide

Estuary Alternative – Low Tide

Hybrid Alternative – High Tide

A visual simulation of the Hybrid Alternative, looking north toward the North Basin and Budd Inlet. The visual simulation was generated to represent the potential viewshed from a North Overlook on the Washington State Capitol Campus. The reflecting pool is full of water and a steel sheetpile barrier wall can be seen at approximately center of the North Basin. The estuary can barely be seen in the distance, along with new 5th Avenue Pedestrian and vehicle bridges.

Hybrid Alternative – Low Tide

Managed Lake Alternative

A visual simulation of the Managed Lake, looking north toward the North Basin and Budd Inlet. The visual simulation was generated to represent the potential viewshed from a North Overlook on the Washington State Capitol Campus. The North Basin is full of water and a new 5th Avenue Pedestrian bridge can be seen in the distance, near 5th Avenue.

Note for North Overlook – KVP-NB-2: The Estuary and Hybrid Alternative simulations were prepared using the design that was available for the Draft EIS. The design of the 5th Avenue Bridge was changed for the Final EIS to avoid significant impacts related to the long-term closure that would be required for its construction. These simulations were not updated for the Final EIS because the new 5th Avenue Bridge would be similar to the pedestrian bridge shown in these images. The 5th Avenue Bridge that is now included in the Estuary and Hybrid Alternatives would be wider, longer, and slightly closer to the viewer than the pedestrian bridge shown in these simulations. The pedestrian bridge is no longer included in the Estuary and Hybrid Alternatives because the new 5th Avenue Bridge would have bicycle and pedestrian facilities. Additionally, the roadway that is shown in the existing 5th Avenue alignment has been replaced by the redesigned and realigned 5th Avenue Bridge. These visual simulations still convey changes at the north end of the project area to inform decision-making.