The Southwest Washington Coastal Erosion Study: a Scientific Research Project to Address Management-scale Objectives

The Southwest Washington Coastal Erosion Study is a five-year, multi-disciplinary research project designed to build a knowledge foundation as a sound basis for addressing coastal management objectives. The purpose of the Study is to gain an understanding of a regional coastal sediment system, the Columbia River littoral cell, in order to support local, state, and federal decision-making in land-use planning, resource allocation, and hazards reduction. In particular, the Study intends to obtain sufficient information so that future coastal conditions, particularly shoreline change and its associated impacts, can adequately be anticipated or predicted. The Study has developed products based on significant findings to assist coastal managers, including preliminary predictions of future shoreline positions. Many types of data and information covering a cascade of temporal and spatial scales are now being integrated to derive vulnerability assessments that consider the probabilities, uncertainties, and constraints of the various factors that influence coastal change. However, due to the inherent complexity of the coastal system, some scientific questions relevant to specific management questions will remain unanswered without additional investigation and/or long-term monitoring. Background For some five thousand years the beaches along the southwest coast of Washington and northwest coast of Oregon accumulated Columbia River sediment, creating broad coastal barrier plains and dune fields. Coastal management issues along the Columbia River littoral cell have historically dealt with problems associated with accreting and drifting dunes that interrupted homeowner views and restricted public access. Incidents of coastal erosion were viewed as localized or temporary problems with minimal societal implications. Questions regarding the permanence and safety of development on the rapidly accreting barrier plains were rarely if ever raised as a management concern, due in part to the high rates of sand accumulation along with relatively sparse and inexpensive development patterns. However, within the past few decades the growth of coastal communities has accelerated while accretion rates have generally slowed and several areas became recognized as exhibiting an erosional trend. Since December 1993, erosion at several sites has struck as community crises, threatening or destroying community infrastructure, resource-based industries, public parks and access, and public and private property. In response to recent erosion problems, over $70 million has been invested in coastal stabilization projects. Land-use planning and coastal permitting decisions in Washington State are primarily made at the local level, and the combined local and state capacity, whether scientific or management-oriented, has been inadequate to address growth and development pressures along the southwest Washington coast. Local governments have lacked basic data and information needed for sound decision-making and long-term coastal planning, and as a result, communities have been relatively unprepared to deal with the magnitude of the problems associated with recent coastal erosion trends. Coastal communities would rarely get beyond informed crisis management (Gale, 1997). Local communities have been grappling with basic questions such as: when or where will the erosion stop?; what constitutes responsible action?; are there feasible interim measures?; what are the appropriate long-term solutions?; and where might other erosion problems occur in the future? The lack of answers to these fundamental questions provided the motivation to initiate the Southwest Washington Coastal Erosion Study in May 1996. Preprinted from the Coastal Society 17 Conference Coasts at the Millennium 9 – 12 July 2000, Portland, Oregon