This thesis examines the role of geographic land use interpretation in flood damage estimation. Sample flood data were drawn from the 1998 flood event along San Francisquito Creek in northern Santa Clara County, California. Spatial flood data for the event were collected from the Santa Clara Valley Water District (the District); depth-damage factors and the flood damage equations were both collected from US Army Corps of Engineers’ (the Corps) publications; and spatial parcel data were collected from the Santa Clara County Tax Assessor’s office (the Assessor).

This study computes flood damages per parcel using the Corps’ recommended equations. Within that computation process the land use classifications from three different agencies and comprising 9-100 land use categories were interpreted to fulfill the calculations. The Tax Assessor’s land uses were generalized into construction land uses in order to identify replacement costs. Construction land use categories were then generalized into the Corps land uses in order to apply depth-damage factors per structure. The flood-affected parcels were then grouped to include the District’s designated land uses. The flood risk was then mapped by land use and described in dollars as a means of choosing an appropriate flood protection measure. The computation was performed per parcel and variations in the economic information conveyed by each agency’s land uses were reviewed.