PHOTO 1
Phase 1 integrated wetland system layout.

PHOTO 2
The riparian habitat and wetlands adjacent to oxbow lakes and the Willamette River will be restored.

PHOTO 3
Thee view today of First Oxbow Lake, where flow and water quality is expected to be enhanced with the integrated Wetlands Program.

PHOTO 4
Planned public overlook of integrated wetland along the Water Trail.

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Project Description

COMPREHENSIVE/INTEGRATED APPROACH

The integrated treatment wetland planning project for the City of Albany, Oregon, primarily addresses water quality issues related to the newly established Willamette Basin total maximum daily loads (TMDLs), especially regarding temperature management. However, the proposed solution was devised to maximize ancillary environmental benefits that affect land and air quality. Realization of these extra benefits was a deciding factor in the selection of this approach.

The proposed solution creates and restores wetlands on agricultural and industrial lands along the river. How this approach will affect the environmental quality of the land converted to these uses was evaluated as part of the planning process. Also, the project is expected to augment channel flows, increase instream habitat, increase quality terrestrial habitat, and foster long-term strategies to restore floodplain function and channel complexity.

Ambient air temperatures were an important factor in the estimation of wetland cooling capabilities. Relying on natural treatment processes avoids air emission issues that might be associated with traditional treatment processes such as mechanical refrigeration or cooling towers. Also, increasing the amount of vegetation in the area is expected to generally improve air quality in the area and provide a carbon offset.

Odor issues potentially associated with discharge of nutrient-rich reclaimed water into wetlands were carefully evaluated through pilot tests of different effluent combinations to select the optimal combination for effective wetland treatment. Analysis of this aspect of the project emphasized the interdependency of the various municipalities and industries in the development of a successful and sustainable treatment system.

Integrated Approach

With CH2M HILL's assistance, the City of Albany implemented an integrated approach that took advantage of the various kinds of resources the City of Albany, the City of Millersburg, and the companies Wah Chang, and Weyerhaeuser had to offer. These included different kinds of treatment capacity, complementary effluent water quality characteristics, land availability, and combined waste load allocations for temperature management.

QUALITY

Long-Lasting Implications

Results from modeling temperature reduction and water quality treatment indicate that the effluent from the wetlands system will significantly outperform permit requirements. The treatment wetlands system creates ancillary environmental enhancements that benefit the watershed and community. Also, energy use and sludge generation will be minimized.

When complete, the natural vegetation and layout will provide wildlife habitat, recreational and education opportunities, as well as improved flood control storage.

Client Satisfaction

With this solution, the cities and partner industries are able to meet and exceed their environmental, social, and financial sustainability goals.

ORIGINALITY/INNOVATION

Innovative Technology

This proposed 185-acre integrated wetland system will be the first in the nation designed to treat a unique combination of municipal and industrial wastewater treatment plant effluents for temperature reduction. Using pilot scale treatability tests, it was found that combining industrial effluent with municipal effluent produced an effluent that was more treatable in a wetland. The treatment wetland configuration incorporates interactions with oxbow lakes in industrial areas along the river to augment flows and improve overall water quality in the watershed.

Development and Use of a Groundbreaking Wetlands Temperature Reduction Evaluation Model

As part of this project, CH2M HILL and Watershed Sciences worked together to modify the Heat Source version 7 model to account for thermal dynamics within a wetland dominated by emergent vegetation. Using data from another CH2M HILL constructed wetland project in the Willamette Valley, the model was calibrated to reproduce measured wetland effluent temperatures. In summary, the model predicted hourly wetland effluent temperatures over 20 months of data and under dramatically varied conditions of influent flows, temperatures, open water area, and climatic conditions. The model was applied to several integrated wetland alternative configurations to select the preferred alternative for implementation.

Regulatory Groundwork

Because this is the first temperature reduction wetland system for combined municipal and industrial effluents, regulatory negotiations have been complex. This process has established permitting criteria that can serve as the groundwork for others considering this approach.

COMPLEXITY

Natural Treatment System Integrated with Oxbow Lakes and Municipal and Industrial Wastewater Treatment Systems: On the basis of a screening of potential technologies and alternatives, which included a preliminary cost comparison of cooling towers, individual wetland treatment systems, and an integrated wetland treatment system, an integrated wetland treatment system was identified as the alternative with the greatest promise. Development of the project included constructed wetland design, watershed-based permitting, water quality credit trading, water rights evaluation, reuse, agricultural sciences, net environmental benefits analysis, and financial analysis. It required soils investigations, hydrogeologic characterization, wetland and waters determination, water quality sampling of the oxbow lakes, sensitive plant species evaluation, and pilot scale treatability tests for the City of Albany, the City of Millersburg, Weyerhaeuser, and Wah Chang involving a series of nine treatment cells containing mesocosms of wetland soil and plants.

Four Entities

Taking an integrated approach that involved the varied requirements, circumstances, wastewater characteristics, flow regimes, and goals of four separate entities, added to the complexity of the planning process. Not only was it necessary to develop and evaluate multiple wetland and treatment configurations for treatment and cost effectiveness, but it was also necessary to define commitments and responsibilities of the participating parties and to develop an implementation plan that addressed separate permitting requirements as they took effect and maintained operational flexibility.

SOCIAL / ECONOMIC ADVANCEMENT

One of the City of Albany's economic goals is to support the retention and expansion of existing businesses and industries in the area. This project does that by working closely with two economically important local industries to create cost-effective solutions to new water quality requirements that could affect their operability in the region. Moreover, the natural treatment system element of their integrated approach produces extra environmental, wildlife, aesthetic, and recreational enhancements for the community that would not otherwise be possible. The treatment wetlands will feature interpretive signs for public education. This facility will become a regional example for others to learn from and the data collected at the site will become publicly available.