Impact of Aquifer Sediments — Minerals — Groundwater Interaction on Hydrochemistry, Aligarh District, Central Ganga Plain, India

Abstract

The sedimentological/mineralogical characteristics of the aquifer material have been determined and their impact on groundwater chemistry is evaluated in the Aligarh district. It is found that 35 % of the aquifer is characterized by sand fraction containing (17–8) % of plagioclase and rock fragment (4–5%). Dominant aquifer material (silt and clay) fraction is dominated by plagioclase, K-feldspar, calcite, chlorite, kaolinite/mica, and halite. Spatial variation in relative positions and thickness of aquifer of silt, clay, and sandy layers resulting to particular hydro-chemical types. Major ions in groundwater shows a high degree of spatial variation along with multisource for the ions. Water quality index suggests that 22% of the water samples fall under the unsuitable category in the area characterized by aquifer material dominant with clay layers.

Groundwater types in the area are dominated by Na⁺-Cl⁻ and Ca²⁺ - HCO₃⁻, Ca⁺² Mg⁺ - HCO₃⁻ Ca⁺² Mg⁺² - Cl⁻ (mixed type). Silicate weathering, Carbonates, salt dissolution, and base ion exchange are the major mechanisms that control the major ionic composition of the groundwater. It is saturated with calcite, dolomite, chalcedony, and Mg-silicate (Sepiolite). The unstable Speiolite under climate conditions prevails in the region rapidly change to smectite clay, which constitutes a major clay mineral of Indo-Gangetic alluvium.

ANN (Artificial Neural Networking) analysis indicated that irrigation quality parameters Permeability Index (PI) and Na% are showing strong relation with selected parameters EC, and Na⁺ concentration. SAR values mostly depend on Na⁺, Mg⁺² conc. and EC, while residual sodium carbonate (RSC) of groundwater can be predicted using Mg²⁺, HCO₃⁻, and Ca²⁺ concentration in groundwater.