Housing Conditions and Site Planning for Flood Vulnerability at the Bingai River Border

Abstract

The Bingai River border  in Binjai City shows an increase in the frequency and depth of inundation which exacerbates the vulnerability of riverside settlements. This study examines how residential conditions and site arrangement (setback, floor elevation, land permeability, drainage, riparian vegetation, and evacuation access) contribute to flood vulnerability, as well as formulate improvement strategies based on SWOT analysis.

Descriptive research was conducted on several border segments with a combination of structured field observations, brief interviews with residents, and inundation maps/drainage networks. Audit indicators include residential typology, floor elevation to ground level, distance of buildings from the river bank, channel type and depth, surface cover/permeability, continuity of riparian vegetation, and availability of evacuation routes. Data were tabulated, mapped simply, and assessed against a matrix of vulnerability (exposure–sensitivity–adaptive capacity). Key findings are then mapped to internal (strengths-weaknesses) and external (opportunities-threats) factors to formulate a TOWS strategy.

The highest vulnerability is concentrated on dense banks with building distances near riverbanks, low floor elevations, shallow/dysfunctional channels, impermeable land surfaces, and disconnected riparian vegetation. A stage or raised floor residence shows better performance than a single-story residence without elevation. The adaptive capacity of communities is relatively aided by social networks and repeated flood experiences, but has not been offset by adequate site planning standards and microinfrastructure.

Flood vulnerability at the border is strongly influenced by micro-decisions at the site scale. Strategic priorities include: (1) rearrangement of setbacks according to border regulations along with riparian green corridors, (2) elevation of floors/stilts and protection of water entry points, (3) rehabilitation of environmental drainage and improvement of permeability (infiltration wells, porous pavement), (4) continuity of riparian vegetation as a buffer of surface flow, and (5) arrangement of evacuation routes and community-based early warnings. The integration of physical-footprint interventions with strengthening the capacity of residents is the key to reducing the risk of flooding in the Bingai River.