produce this desirable outcome; they often, lead to hostility, mistrust, and entrenchment.

Processes that allow deliberation over time can gradually build the kind of public trust that provides a solid basis of public actions. Concern over and resulting responses to deteriorating conditions in Seattle's Lake Washington are a case in point (see case study below). Deliberation, debate, and a role for scientific understanding were common themes at all stages, from recognition that a problem existed through taking action to monitoring to ensure that lake conditions do not again deteriorate. Although it was not a concern for enhancing biodiversity that initially led to action, the results have done just that. The lake is now managed by a number of agencies, and numerous municipalities are involved.

Case Study: Lake Washington

Community reaction to ameliorate perceived environmental change has a long history, beginning at least in the 1600s, long before the general term biodiversity had been coined. We encapsulate here details on Lake Washington as an example with generalizable implications for many urban lakes. Intervention (management) was motivated by developing health issues and a state of the lake that was increasingly intolerable to the public (the stakeholders). Scientific information played a major role in guiding the management decisions, in diverting first untreated sewage (a health issue) and eventually the treated waste fluids (a plant-nutrient issue). The lake is now scientifically managed at an acceptable water quality for the combined benefit of many categories of users.

The development of Seattle, from its founding in 1851 as a small coastal village to its current status as a major West Coast port and metropolitan area, has been accompanied by typical growing pains and associated costs. The city is essentially squeezed between two major bodies of water: Puget Sound to the west and Lake Washington to the east. The latter is a relatively young post-Pleistocene lake, formed about 12,000 years ago; it is 28 km long and 65 m deep at its deepest and has a surface area of 86.5 km2. By 1860, lake-side land development and deforestation had begun; by 1900, the lowland conifer forest had been cut, and raw sewage had begun to enter the lake (Edmondson 1991). In its pristine form, the lake was connected to Puget Sound and in its deeper portions was mildly brackish, as indicated by diatom remains in the lake's sediments. The diatom assemblage suggests little effect by a small American Indian population on the lake's biota before to the arrival of European settlers (Bagley 1916). Seattle's increasing importance as a port prompted major changes in the lake's architecture in 1916. The level was lowered by 3 m, and the lake was connected to Puget Sound through a new, locked ship canal, which both increased commercial ship traffic to and from the lake and, by reducing the influx of seawater, influenced lake water chemistry. Furthermore, a major river, the Cedar, was



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