Singh Surjeet, Ghosh N C, Gurjar Suman, Krishan Gopal, Kumar Sumant, Berwal Preeti
National Institute of Hydrology, Roorkee, Uttarakhand, 247667, India.
Environ Monit Assess. 2017 Dec 19;190(1):29. doi: 10.1007/s10661-017-6407-3.
Agriculture is a major sector in India which contributes around 14% of country's gross domestic product (GDP). Being an agriculture-based country, good quality of water for irrigation has been a prime requisite. Highly growing population and accelerated industrial development are causing anthropogenic pollution to both surface and groundwater on one side and geogenic contamination like arsenic, fluoride, high dissolved solids, sodicity, and iron in groundwater on other side. As a result, ensuring safe water quality for the irrigation has become a major challenge to both the central and state governments. The present irrigation water quality standards being followed in India have been set by the Central Pollution Control Board (CPCB) and Central Ground Water Board (CGWB) in the year 2000. These standards are solely based on four parameters, namely electrical conductivity, sodium percentage, sodium absorption ratio, and residual sodium carbonate, which are quite subjective and many times are not capable to exactly decide the quality of irrigation water particularly when there are large variations in the source water quality. Therefore, in the present paper, an indices-based approach is presented for categorization of irrigation water quality. These indices are mathematical equations that transform water quality data into a numeric value, which describes the quality of irrigation water. The proposed irrigation water quality index (IWQI), which is based on 12 parameters, classifies the water into five categories, viz. excellent, good, medium, bad, and very bad in the same manner as given by the CPCB and CGWB. In order to give proper rating to various parameters of the index, weights are computed using Saaty's analytic hierarchy process (AHP)-based multiple criteria decision analysis (MCDA) approach. This approach minimizes the subjectivity in assessment of weights and improves understanding of water quality issues by generating an overall index to describe the status of water quality. The proposed index will be beneficial for the water management authorities in ensuring safe water to the stakeholders.
农业是印度的一个主要部门，约占该国国内生产总值（GDP）的14%。作为一个以农业为基础的国家，优质的灌溉用水一直是首要需求。人口的快速增长和加速的工业发展一方面导致了对地表水和地下水的人为污染，另一方面导致了地下水中诸如砷、氟化物、高溶解固体、碱度和铁等地质成因污染。因此，确保灌溉用水的安全水质已成为中央和邦政府面临的一项重大挑战。印度目前遵循的灌溉用水质量标准是由中央污染控制委员会（CPCB）和中央地下水委员会（CGWB）在2000年制定的。这些标准仅基于四个参数，即电导率、钠百分比、钠吸附比和残留碳酸钠，这些参数相当主观，而且很多时候无法准确判定灌溉用水的质量，特别是当水源水质存在很大差异时。因此，在本文中，提出了一种基于指标的方法来对灌溉用水质量进行分类。这些指标是将水质数据转换为数值的数学方程，该数值描述了灌溉用水的质量。所提出的灌溉用水质量指数（IWQI）基于12个参数，将水分为五类，即优秀、良好、中等、差和极差，分类方式与CPCB和CGWB的相同。为了对该指数的各个参数给出恰当的评级，使用基于萨蒂层次分析法（AHP）的多准则决策分析（MCDA）方法计算权重。这种方法将权重评估中的主观性降至最低，并通过生成一个描述水质状况的总体指数来增进对水质问题的理解。所提出的指数将有助于水资源管理当局为利益相关者确保安全用水。
