TITLE:
Satellite-Based Assessment of Quarry-Induced Vegetation Degradation at Kaseve Quarry, Machakos County, Kenya (2015-2024)
AUTHORS:
Charles Ngala Kithome, Julian A. Ogondo, Mary Mwangi
KEYWORDS:
Quarrying, Vegetation Degradation, NDVI, Remote Sensing, Landsat-8, Sentinel-2, Machakos County
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.4,
April
28,
2026
ABSTRACT: Quarrying activities are a significant driver of vegetation degradation globally, yet quantitative assessments of their ecological impacts remain limited, particularly in Sub-Saharan Africa. This study evaluates vegetation loss at Kaseve Quarry in Machakos County, Kenya, using Normalized Difference Vegetation Index (NDVI) analysis derived from Landsat-8 and Sentinel-2 satellite imagery spanning 2015 to 2024. The research employed a descriptive and quantitative design, processing multi-temporal satellite data through Google Earth Engine to generate annual NDVI composites. Spatial analysis was conducted across distance-based zones (0 - 250 m, 250 - 500 m, 500 - 750 m, 750 - 1000 m, and >1000 m reference zone) and directional sectors around the quarry boundary. Ground-truthing validated satellite-derived indices. Results revealed a substantial 49.1% decline in NDVI values within the quarry area (from 0.55 in 2015 to 0.28 in 2024), while the reference area maintained stable values (0.55 - 0.58). Linear regression analysis demonstrated a highly significant negative trend (−0.0297 NDVI units/year, R2 = 0.984, p