A Buoyancy-Based Feasibility Framework for Amphibious Housing in Indian Riverine Floodplains: A First-Principles Design and Material-Sensitivity Analysis

Abstract

Riverine flooding is among the most frequent and damaging natural hazards in India, and conventional responses based on permanent elevation or post-flood reconstruction impose recurring costs on low-income households. Amphibious construction, in which a dwelling rests on the ground in dry conditions and floats on rising floodwater, offers an adaptive alternative, yet quantitative feasibility evidence calibrated to Indian design standards and affordable-housing norms remains scarce. This study develops a transparent, first-principles buoyancy framework for a representative single-storey amphibious dwelling sized to the Pradhan Mantri Awas Yojana minimum dwelling envelope (a 3.5 m by 6 m plan, 21 m²). Using material unit weights and imposed loads drawn from the relevant Indian Standards, a load take-down, an Archimedes buoyancy and freeboard analysis, an expanded-polystyrene reserve-buoyancy calculation, and a guide-pile hydrodynamic check were carried out for three superstructure options: reinforced concrete, fibre-cement panel, and bamboo or treated-timber walls. The analysis shows that a shallow 0.6 m pontoon is structurally inadequate in every case, producing negative freeboard and a factor of buoyancy below unity (0.31 to 0.55). Superstructure mass emerges as the dominant design lever: a reinforced-concrete superstructure requires a pontoon depth of about 2.69 m to achieve a 0.3 m freeboard, whereas lightweight bamboo or fibre-cement walls reduce this requirement to roughly 1.6 m and lower total weight by more than 40 per cent. Guide piles govern only at flood-current velocities above approximately 2.6 to 3.6 m/s, confirming that the concept is best suited to low-velocity overtopping floodplains rather than fast-flowing channels. The framework provides a reproducible pre-design envelope for practitioners and aligns with United Nations Sustainable Development Goals 9, 11 and 13. All computations are derived from secondary standards data; no laboratory experimentation is claimed.