April 1997 Volume 3, Issue 2

Sensitive areas like steep slopes and flood plains are still making the news in this, one of the wettest winters and springs in years! Other sensitive areas like streams, landslide, and erosion hazard areas also concern homeowners and public officials this time of year. The remaining dramatic but lesser known hazard areas: coal mines, volcanic and seismic areas are also regulated.

Each county and city will provide environmental "sensitive" or "critical area ordinance" information upon request. In addition Bellevue publishes a "Sensitive Area Notebook" and Mercer Island publishes "A Field Guide to Mercer Island's critical Areas. The Environmental Division of King County Department of Development and Environmental Services at 296-6660 provides pamphlets on each of the nine sensitive areas.

In our last newsletter we described the benefits of views onto open space, wildlife and privacy that sensitive land offers your custom home site. We also briefly described the permit process an owner and architect undergo to meet the environmental zoning and building codes that apply to sensitive areas. The State Environmental Policy Act (SEPA) requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. Each city and county defines its own "sensitive" or "critical" areas and their ordinances vary. As part of the permit process in the early phase of design DePape Associates works in each jurisdiction on behalf of owners who wish to utilize precious land. Let's take a look at a few of these sensitive areas and just how they are typically identified and regulated.

Three sensitive areas: flood plains, wetlands and streams have water in common. Cities and counties are concerned with wildlife and fish habitat preservation, storm water reaching the Sound and the quality of the acquifer that we all depend on for potable water. Thurston County lists "protecting the general public from avoidable losses" among its concerns and includes shoreline bluffs among its sensitive areas as does Snohomish County. The Federal government is concerned with the cost to infrastructure and emergency relief for victims of disasters and has jurisdiction in flood plains in all counties. Building within guidelines is still possible around these often beautiful and useful areas.

By definition "wetlands occur where the soil is wet for enough time during the growing season to affect which species of plants can grow . . ." However, a wetland does not necessarily have to have standing water for the requisite "seven continuous days during the growing season". Water saturated soils that support water tolerant classes of plants like wet meadow, marsh, bog, forest and "scrub shrub" are also considered wetlands. Wetlands are classed by sensitivity for plant and animal life they support and have corresponding protective buffers that range from 100 to 25 feet. The presence of an adjacent sensitive area like a steep slope usually increases the buffer zone. In some jurisdictions (King County for instance) structures that existed within these buffers prior November 1990 may be remodeled, reconstructed or replaced.

Artificial watercourses that support the salmonid fish species or a stream bed which may have water for only "part of the year" qualify as a sensitive areas because they support wildlife. Streams are divided into three classes based on the quantity of water they carry and the wildlife they support. Buffers range from 150 feet to 25 feet in order to reduce to the impact of human activity on streams. Adjacent slope or wetland sensitive areas add to the width of the buffer area. Any activity such as underground utility placement, roads and trail building even planting or firewood cutting is regulated within the buffer area.

Flood Hazard Areas were primarily identified to prevent the filling in of the flood plain with building that displaces and therefore aggravates flooding. A " 100 year flood plain" is land which is calculated to be "covered by a base flood which has a one percent chance of occurring each year." The Federal Emergency Management Administration and Counties regulate flood plains. Federal maps and county inventory maps trace the "base flood elevation (BFE)" the basis for determining new building or renovation of existing structures and flood insurance eligibility. As with most sensitive areas the owner is expected to provide professional certification as to the appropriateness of his or her project preceding application for a building permit. One of our specialties at DePape Associates is assisting clients in evaluating sensitive lands they may own or are considering for purchase.

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