Groundwater Quality Dynamics in a Himalayan Urban Settlement: Evidence from Nagar Panchayat Arki, Solan, Himachal Pradesh, India

Abstract

This study evaluates groundwater quality dynamics in Nagar Panchayat Arki, Solan, Himachal Pradesh, in the context of rapid urban expansion. Groundwater samples from seven sites (S1–S7) were analysed for physicochemical and biological parameters, revealing significant spatial variations driven by urbanisation, waste disposal, and anthropogenic activities. While pH levels (6.80–7.34) remained within the permissible BIS limit (6.5–8.5), turbidity varied widely (0.6–70.7 NTU), peaking at S1, S2, and S4 due to soil erosion, construction, and urban runoff. Total dissolved solids (195–411 mg/L) and electrical conductivity (up to 642 uS/cm) were elevated in densely populated zones, signalling high ion discharge from sewage, detergents, and construction debris. Fluctuations in hardness and alkalinity reflected both geological factors and household waste leakage. Site S4 showed excessive chloride levels, potentially reflecting wastewater infiltration. Notably, dissolved oxygen dropped dangerously low to 1.9 mg/L, and biochemical oxygen demand exceeded 3 mg/L at several points, indicating possible organic contamination. The Water Quality Index (WQI) categorised groundwater at S1, S2, and S4 as "very poor" (WQI 525–751), whereas S3, S5, and S7 maintained "good" quality. Overall, the findings indicate spatial differences in groundwater quality that warrant investigation of local influences. Implementing sustainable urban planning and proactive management strategies is critical to protecting groundwater resources in this fragile Himalayan ecosystem.