Chemical Characteristics of the Karmanasha River Water and Its Appropriateness for Irrigational Usage

Abstract

Water is a prime natural resource and precious national asset and one of the chief constituents of the environment. The chemical characteristics play a key role in terms of ecological and economic perspectives in the river water. The characterization and evaluation of river water quality in the Karmanasha River is necessary due to its immense importance in the livelihood of the people in the core urban areas of Kathmandu valley, Nepal. In this study, the surface water samples were collected from 16 sites with a 0.5 km interval to characterize and evaluate the water quality mainly from the perspective of its irrigational usage. The assessment was carried out by applying electrical conductivity (EC), sodium percentage (Na%), sodium adsorption ratio (SAR), permeability index (PI), Kelly’s ratio (KR), magnesium adsorption ratio (MAR), cation ratio of soil structural stability (CROSS), Wilcox diagram and water quality index (WQI) including the general hydrochemistry. The general hydrochemistry of river water indicates slightly alkaline in nature with mean pH value 8.07, and the dominance order of major ions follows the pattern of Ca2+>Mg2+>Na+>K+ for cations, and HCO3->Cl->NO3- for anions. Furthermore, the results revealed that the water is safe for irrigation purposes based on EC, Na%, SAR, KR, MAR, CROSS, and Wilcox diagram. The results also specified that no severe degradation in water, however, the low DO, and high BOD and COD values than that of the standard value prescribed by Nepal Drinking Water Quality Standard, signify the anthropogenic signature in the river water. This study provides the baseline information about the WQI and suitability of irrigation water quality, and further in-depth studies are required at spatiotemporal levels to get in-depth insights about the ecological health of the river.

Hydrochemical Assessment Of Jhilmila Lake, Kanchanpur, Nepal

“…High pH favors the precipitation of ions and also affects the carbon dioxide, carbonate, and bicarbonate equilibrium in the aquatic system. The average pH of the water in the lake was slightly alkaline (i.e., 7.35) indicating the lake has carbonate-dominated underlying lithology, and also exhibited that the lake water was suitable for drinking purposes from the perspective of pH values 15 .…”

Distribution and risk appraisal of dissolved trace elements in Begnas Lake and Rupa Lake, Gandaki Province, Nepal

“…The WQI has been widely used in recent years for the water quality assessment [23,36,37]. In this study, to assess the WQI of lake water using TEs, the weight of each TEs (Wi) was assigned according to the relative significance of the elements [1].…”

Water quality and health risk assessment of trace elements contamination in Ghodaghodi Lake, Sudurpaschim Province, Nepal

“…The lake is rich in aquatic macrophytes, fishes, birds, reptiles, and mammals (Lamsal et al, 2014). The persisting anthropic activities like excessive harvesting, poaching, habitat destruction, population pressure, forest fragmentation, siltation, excessive use of fertilizer and pesticide seepage have threatened the existing ecological conditions in the lake (Acharya et al, 2020;Pant et al, 2021c;Tripathee et al, 2016;Xiao et al, 2014).…”

“…For this study, WHO drinking water quality guidelines were taken as reference for each TE, and their weights (Wi) were assigned using the values from Tripathee et al (2016). The computed WQI values were classified into five different categories (Acharya et al, 2020): excellent (WQI < 50), good (WQI = 50 -100), poor (WQI = 100 -200), very poor (WQI = 200 -300), and unsuitable for drinking purpose (WQI > 300).…”