Planning for Climate Change and Wastewater Infrastructure Resiliency


  • Dwayne Amos PE, Anni Luck PE - Hazen and Sawyer

Hazen and Sawyer has developed a resiliency framework that facilitates an efficient and comprehensive vulnerability assessment while also allowing for flexible adaptation planning that accommodates varying stakeholder, budgeting, and scheduling constraints.

The first phase involves establishing flood elevations that account for both a 100-year storm event and future sea level rise (SLR). The elevation to which assets must be protected may vary depending on funding agency requirements.

The vulnerability assessment determines which facilities and which assets are most at risk, and presents the information in an easy-to-understand, searchable, and sortable database. Once the assessment is complete, we work with the utility to develop interim adaptation measures, including storm surge guidance placards, to help operators proactively prepare for a surge event.

Finally, the assets are prioritized for adaptation measures. Alternative adaptation strategies are evaluated and compared on a number of factors including feasibility, costs, and levels of protection provided.

Among the many manifestations of climate change, it is virtually certain that sea levels will continue to rise for many centuries. Coupled with the effects of storm surge from more frequent and intense extreme events, resulting impacts are expected across a range of sectors, predominantly in densely populated coastal regions. The damage incurred from Hurricane Sandy provided a stark reminder to utilities that more effective planning and risk assessment is required to mitigate damage in the future. Within the water resources sector, water and wastewater treatment infrastructure are particularly vulnerable due to their placement at low-lying elevations for collection by gravity and proximity to water bodies for discharge purposes. Protection of these facilities is of vital importance to avoid disruption of public service, damage to equipment, and spillage of wastewater into nearby waterways.

Adaptation design and implementation can be complicated by evolving or conflicting stakeholder needs. Balancing capital budgets and the level of desired protection is intrinsic to most designs. Use of different funding sources (for example FEMA, EPA and state revolving funds) on the same resiliency project may result in varying scheduling requirements and protection requirements as reflected in different design flood elevation determinations. Differing stakeholder preferences for project bundling could also impact final resiliency design and implementation. As such, successful resiliency projects must not only address specific infrastructure risks, but also allow for flexible resiliency planning which can evolve to balance stakeholder requirements. The purpose of this talk is to walk through a proven resiliency framework that facilitates an efficient and comprehensive vulnerability assessment while also allowing for flexible adaptation. Multiple resiliency projects along the east coast will be discussed to provide background of the planning required to implement an effective design and protection of vital wastewater treatment and conveyance infrastructure.

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Horizons Fall 2017 (pdf)

Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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