Erratic monsoon regimes and their influence on terrace farming viability in Uttarakhand Hills

Abstract:

For centuries, bench terraces carved into the steep flanks of the Uttarakhand Himalaya have sustained smallholder rice, wheat, and millet cultivation by capturing monsoon rainfall on otherwise uncultivable slopes. But the monsoon itself is changing. This research investigated how erratic monsoon onset, mid-season dry spells, and altered withdrawal timing have affected terrace farming viability across three elevation zones in the Almora and Bageshwar districts of Uttarakhand between 2000 and 2023. Daily rainfall data from six India Meteorological Department stations were analysed alongside a composite Terrace Viability Index (TVI) constructed from five field-measured parameters: soil moisture retention, wall structural integrity, active cultivation fraction, crop yield per unit area, and seasonal labour input. Over the 24-year window, monsoon onset shifted later by a mean of 8.9 days relative to the 2000-2005 baseline, and mid-season dry spells exceeding 12 consecutive days doubled in frequency. The TVI declined from 76.8% to 44.3% in the mid-elevation band (1,200-1,800 m) and from 71.4% to 28.1% above 1,800 m. multiple regression showed that onset delay and dry-spell frequency jointly explained 79% of TVI variance after controlling for elevation and road access. These results indicate that monsoon irregularity not just total rainfall decline is the primary driver of terrace degradation, and that viability thresholds may be crossed within a decade at high elevations if current trends persist.