TITLE:
The Influence of Alluvial Mining on the Morphology and Ecological Health of the Jhimruk River in Pyuthan, Nepal
AUTHORS:
Ankit Kandel, Kismat Pokhrel, Lenin Adhikari, Deep Narayan Shah
KEYWORDS:
Alluvial Mining, Physical Assessment, Biological Assessment, Water Quality Assessment, Jhimruk River, Sand Mining
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.8,
August
9,
2023
ABSTRACT: Historically, alluvial rivers have been a desirable source of sediment for
various industrial purposes. However, the demand for sand is rapidly increasing,
leading to environmental concerns associated with its extraction. The extraction
of sediment from riverbeds has both visible and invisible effects. This research
aims to investigate the dynamics of the Jhimruk River’s morphology and its impacts
by evaluating the river’s quality and studying its changing morphology. To assess
morphological changes, satellite images from different years were compared using
Geographic Information System (GIS). Physical assessments were conducted by calculating
a Habitat score based on various parameters. Water quality assessments involved
measuring factors such as pH, temperature, nitrate levels, and alkalinity. A water
quality map of the river was generated using color coding to indicate different
conditions. The Habitat score demonstrated variations in the data collected from
all sites, with factors such as instream cover, bottom substrate stability, riparian
vegetation, and aesthetic of the river stretch playing crucial roles in influencing
the total score. The Water Quality Index value for the disturbed site indicated
moderate pollution, falling under class II. Aquatic macroinvertebrates displayed
natural responses to increasing levels of stressors across their life stages, as
observed through the analysis of the GRS-BIOS/ASPT index. With the exception of
the disturbed site, all other sites were classified under water quality class II,
while the disturbed site belonged to class III, indicating a moderate to critically
polluted state for most of the Jhimruk River. Furthermore, an increase of 180.87
meters in the river width at the disturbed site provided evidence of morphological
changes occurring over the specified period. Mining activities were identified as
a significant contributor to the alteration in river morphology.