The shortage of available land for residential development in the San Francisco Bay Area has led to the improvement of sites having marginal subsurface conditions. Among these sites are those with steep or mountainous topography as well as reclaimed marshlands. This article will deal exclusively with the unique engineering problems encountered in marshland development.

The reclamation of tidal marshlands or underwater areas has typically involved diking to a level above high tide and filling within the dikes with a few feet of imported fill over soft, compressible marsh soils. The ensuing behavior of the final product has been a matter of concern to both engineers and land developers. In some instances, large total and differential settlements of the surface, as well as instability within the underlying soft clay, have caused failures of structures and underground utilities.

A thorough investigation of soil conditions, combined with careful planning and analysis is necessary to produce rational and satisfactory foundation design and construction in areas formerly considered unusable. Land reclamation and development of Redwood Shores, in Redwood City, California, is showing that good planning, design, and construction fitted to the soil conditions can successfully convert tidal marshes into usable land quickly and economically.