Climate Change and Sea-Level Rise in OlympiaBy Vince McGowan The City of Olympia has been concerned about climate change for over 17 years. Early in 1990, a local citizen from the Greenhouse Action Group approached Olympia's City Council to ask what the City was doing to address the issue of global warming. This prompted the Council to make action on global warming one of its target issues for the next year. Council formed an interdepartmental Global Warming Task Force to begin addressing climate change and prepare a background report on its implications for Olympia. The Task Force relied on a major report by Vancouver, BC and technical guidance from the Washington State Department of Ecology to produce a report that identified areas where the City had authority to act, steps the City had already taken, and possible future actions. Following publication of this background report, Council passed a resolution committing the City to a long-term strategy to reduce greenhouse gas emissions, increase tree cover and prepare for climate change. The background report identified sea-level rise as one of the primary impacts Olympia must address. The City completed a subsequent report titled "Preliminary Assessment of Sea Level Rise in Olympia, Washington: Technical and Policy Implications" in June 1993. This report describes sea-level rise predictions as they were known at the time, provides an overview of potential impacts, and discusses strategies and policy considerations. Earlier this year, the City renewed its commitment to address climate change, beginning with sea-level rise. The 1993 report on sea-level rise was dusted off and found to still be remarkably relevant. Maps were updated and current projections of the amount and rate of sea-level rise were considered. The facts remain largely the same. Sea level is rising in Olympia by about one foot per century due to post-ice age warming of the oceans and land subsidence. This rate will increase with increased global climate change. Much of Olympia's downtown is at risk, lying only one to three feet above the current highest high tides. If no protection measures are taken, the one foot of sea level rise predicted by 2050 would result in ponding on some streets and flooding of low-lying structures during the extreme high tides that occur once or twice a year. A two-foot rise would impact an even greater area. Pipes designed to convey stormwater away from downtown would be unable to discharge fast enough to prevent flooding during storms. At higher levels, flows would reverse and the sea would flow out of street drains and into the streets. A three-foot sea level rise - offered as a mid-range prediction by 2100 - would overtop many places along the shoreline and flood most of downtown Olympia during extreme high tides. The wastewater system is combined with stormwater in much of the downtown. Higher sea levels would flow into the wastewater pipes through combined drains and infiltrate through pipe joints, challenging capacity at the LOTT regional wastewater treatment plant. Outside of downtown, the City's major drinking water supply source at McAllister Springs is subject to saltwater intrusion with rising sea levels. The City is planning a new wellfield upgradient from the springs and this will help mitigate the risk. While this will protect the City's drinking water, many natural systems at risk don't have the option to move up to accommodate rising sea levels. Tide flats, estuaries, and coastal wetlands are expected to decline dramatically with a rising sea. These systems emerge in response to a delicate balance of inundation and exposure as tides move in and out and salt and fresh waters mix. Some habitats will be able to move and adapt while others will meet bulkheads and other shoreline armoring measures and be lost. With so many impacts to both the built and natural environments, the City's climate change initiative was broadened into a commitment to sustainability. Since the early 1990s, the City has focused on climate change mitigation and other sustainability efforts, implementing policies to reduce greenhouse gas emissions and sustain natural resources. Internally, the City has reduced municipal vehicle emissions, increased biodiesel usage, and moved towards utilizing 100 percent green power for all utility electricity needs. The City's water conservation and reclaimed water programs have mitigated the impact of increasing water demand; land use and transportation policies have promoted denser, less auto-dependent development; stormwater management, forest preservation and street-tree planting have helped reduce the effects of urbanization; and the new waste management plan aims to move the City toward Zero Waste. The City's current work plan includes preparing a status report on climate change in Olympia with recommended next steps for further emission reductions and risk assessments, as well as a shift towards implementation of adaptation strategies. The City will be engaging the community through public forums and other educational activities. The City is also forming partnerships among its Thurston County neighbors, drawing on resources from Ecology, the Climate Impacts Group and others, and currently serves on the statewide Coastal/Infrastructure Preparation/Adaptation Working Group to recommend strategies to meet Governor Gregroire's Washington Climate Change Challenge. Vince McGowan is a Senior Program Specialist for City of Olympia's Public Works Water Resources department. He may be reached at vmcgowan@ci.olympia.wa.us.
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