Water quality and land use/cover changes in the Phewa Watershed, Gandaki Province, Nepal

Abstract

Knowledge and understanding of land use and water quality nexus is an important precursor for assessing the human-water interactions and sustainable freshwater management. In this study, the land use/cover change (LUCC) and water quality assessment with respect to drinking and irrigational purposes were carried out in Phewa Lake, Nepal. A total of 20 water samples were collected during the winter and summer seasons in 2017 and were analysed for major hydrochemical variables. The water quality index of Phewa Lake was found to be 5.15 and 2.57 during the winter and summer, respectively, indicating the suitability of water for drinking purposes. The results revealed that the electrical conductivity, sodium percentage, and sodium adsorption ratio were found to be 38.80 µS/cm, 16.99, and 0.10, respectively in the summer and 85.06 µS/cm, 14.68, and 0.15, respectively in the winter. Similarly, permeability index, Kelly’s ratio, magnesium hazard, cation ratio of soil structural stability, and Wilcox diagram exhibited that the water was suitable for irrigation in both seasons with relatively better quality in the summer. The dynamic pattern of LUCC in the Phewa watershed exhibited an increase in the spatial extent of forest, shrub-land, grassland, and built-up area, whereas decreasing trend of agricultural land, barren land, and water bodies. Irrespective of the seasonality, the LUCC-water quality nexus showed elevated concentrations in the proximity of the urban settlements. The present study could be helpful for the restoration of water quality by sustainable land-use practices in the Himalayan region.

Imprints of COVID-19 lockdown on the surface water quality of Bagmati river basin, Nepal

“…In order to confirm the irrigation water quality results, the Wilcox diagram was applied. It includes four major groups of irrigational water quality namely (i) C1S1, (ii) C1S2, C2S2, C2S1, (iii)C1S3, C2S3, C3S1, C3S2, C3S3, and (iv) C4S4, C4S1, C1S4, C2S4, C3S4, C4S4, C4S3 as completely effective for agriculture; brackish-approximate perfect for agriculture; passion-useable for agriculture and very passion-harmful to agriculture, respectively ( Alavi et al, 2016 ; Bishwakarma et al, 2019 ). Most of the sampling points of the main river and its tributaries fell under C3S1 and C2S1 sections ( Fig.…”

Hydrochemical characterization and irrigation suitability of the Ganges Brahmaputra River System: review and assessment

“…The chemical and physical characteristics of river water using for irrigation purposes are the basic consideration for the irrigation water quality evaluation. Specific properties of irrigation water have relevant relation to the quantity and quality of crops, maintenance of soil properties, and surrounding environmental balance (Alobaidy et al 2010;Bishwakarma et al 2019). The Food Agriculture Organization (FAO) has provided the permissible limit for irrigation water standards according to the physicochemical parameters of irrigation water (Table 1).…”

Effects of COVID-19 lockdown on hydrochemical properties of the Brahmaputra River, India

“…(Bishwakarma et al, 2022). 25 The Piper diagram, dendogram diagram, Gibbs diagram and Wilcox diagram were prepared using OriginPro 2022b (Learning edition).…”

“…Water for irrigation can be classi ed into four types based on sodium absorption ratio (SAR) values (Guettaf et al, 2017). 22 25,17 According to Fig. 9, the bulk of the samples taken before the lockdown fell into the C1-S2 and C1-S3 categories, indicating that they were roughly perfect and ideally suited for agricultural usage.…”