প্রাচীন ভারতের পরিবেশবিজ্ঞান : বৃহৎসংহিতায় ভূগর্ভস্থ জলের সূচক/ Ancient Indian Environmental Science: A Study of Groundwater Indicators in Varāhamihira’s Bṛhatsaṁhitā

Abstract

Varāhamihira’s Bṛhatsaṁhitā, composed in the sixth century CE, represents a remarkable synthesis of empirical observation and environmental reasoning. While Varāhamihira is conventionally recognized for his contributions to astronomy and mathematics, the Udakārgala section of the fifty-fourth chapter reveals a sophisticated understanding of groundwater systems through ecological and biological indicators. This study examines Varāhamihira’s method of identifying subsurface water using plant morphology, physiology, soil characteristics, and micro-environmental variations, and situates it within the framework of modern environmental science and hydrogeology.

       The Bṛhatsaṁhitā systematically associates the presence, depth, flow direction, and quality of groundwater with specific vegetational patterns—such as tree species combinations, branching structures, leaf texture and coloration, flowering anomalies, canopy density, grassland transitions, and the presence of creepers, anthills, and fauna. These indicators are not episodic but represent long-term ecological responses to sustained subsurface moisture. Varāhamihira implicitly recognized that groundwater-bearing strata generate localized microclimatic zones, influencing soil moisture, atmospheric humidity, and plant vitality even in otherwise arid landscapes.

      From the perspective of modern environmental science, these observations correspond closely with contemporary concepts such as plant bioindicators, eco-hydrology, vegetation–soil–water interaction, groundwater-dependent ecosystems (GDEs), and phenological responses to subsurface hydrological conditions. Modern hydrogeology similarly acknowledges that variations in plant structure, chlorosis, canopy formation, root behavior, and species distribution can reflect groundwater depth, salinity, and aquifer dynamics. The text’s emphasis on grassland-to-non-grassland transformations aligns with current understandings of capillary water movement, soil aeration stress, and fluctuations in the vadose and phreatic zones.

This comparative analysis demonstrates that Varāhamihira’s groundwater detection methodology was empirically grounded rather than symbolic or ritualistic. His approach constitutes a proto-scientific hydrological model based on sustained environmental observation rather than mechanical instrumentation. Reassessing these ancient indicators through modern scientific frameworks not only validates their ecological relevance but also enhances contemporary approaches to sustainable groundwater exploration, particularly in arid and semi-arid regions.

       Ultimately, this study positions the Bṛhatsaṁhitā as an early interdisciplinary environmental text, bridging classical knowledge systems and modern environmental science. It invites further research into historical eco-hydrological models and underscores the relevance of traditional ecological knowledge in addressing present-day water resource challenges.