Seasonal Physico-Chemical Water Quality and Aquatic Macrophyte Diversity of Victoria Lake (Bada Talab) in Lohardaga, Jharkhand, India

Abstract

Lakes across India face sustained pressure from domestic effluent discharge, siltation and unplanned catchment development, and the physico-chemical condition of such lakes is widely reported to shape the structure of their aquatic macrophyte communities. This paper illustrates a statistical workflow for relating monthly physico-chemical water quality data to seasonal aquatic macrophyte diversity in Bada Talab, Lohardaga, referred to here as Victoria Lake, using a simulated water quality time series (36 monthly records, January 2018–December 2020) and macrophyte cover data recorded on three sampling occasions (June 2018, December 2018 and March 2019). Fourteen physico-chemical parameters were examined, including temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), electrical conductivity, total dissolved solids, turbidity, hardness, alkalinity, chloride, sulphate, nitrate and phosphate. Macrophyte diversity was quantified using the Shannon–Wiener index (H′), species richness and percentage cover of the dominant species. Species richness increased from 12 (June 2018) to 57 (March 2019), the Shannon–Wiener index rose from 1.48 to 3.54 over the same period, and the percentage cover of the dominant species fell from 44.9% to 10.4%, consistent with a shift from a low-diversity, dominance-structured assemblage towards a more even, species-rich community. Pearson correlation analysis among the water quality parameters revealed a strongly inter-correlated block of variables (COD, electrical conductivity, total dissolved solids, turbidity, hardness, alkalinity, chloride, sulphate, nitrate and phosphate; r = 1.00) moving inversely with dissolved oxygen (r = −1.00), a pattern of near-perfect covariance that is characteristic of a synthetically generated series rather than field-measured data and is reported here as an explicit data-quality caveat. Because only three macrophyte sampling occasions were available, the correlation between diversity indices and water quality parameters (n = 3, 1 degree of freedom) could not be evaluated with meaningful statistical power and is presented descriptively rather than as a confirmed relationship. The paper is intended as a transparent demonstration of the methods, tables, figures and reporting conventions appropriate for physico-chemical–macrophyte correlation studies of Indian urban lakes, and it identifies the field sampling design that would be required to test the relationship rigorously.