Water Quality Time-Series Modeling and Forecasting Techniques

Introduction

Water is an essential natural resource that plays a significant role not only for human beings but also for all living organisms for life's survival purpose (Budiarti et al., 2019). Water quality represents the physical, chemical, and biological characteristics of the water depending on the standards for various applications (Swenson, 1965), (Johnson et al., 1997). Hence, the quality of the water plays a critical role in different aquatic systems such as oceans, reservoirs, ponds, lakes, etc., for the sustainability of aquatic bodies and living organisms that depend on the particular water system (Y. Chen et al., 2020). Although the water is abundantly available, all of it is not suitable for drinking purposes. Hence, the limited freshwater should be conserved and used properly for the continuation of the living things. Most of the natural resources are getting damaged due to the unsustainable use of several innovations for maintaining an easy lifestyle. Subsequently, many diseases like typhoid, dysentery, cholera, skin infections, eyes, and gastroenteritis, hepatitis is spreading among people due to due to usage of poor quality water (U. Ahmed et al., 2019). Particularly, in India, water bodies have been destroyed due to unsustainable urbanization and mechanization-driven growth. According to the estimations of expertise, nearly 70% of surface water in India is not suitable for human use (Chawla et al., 2015). Each day, water bodies and water sources are getting mixed with 40 million liters of sewage on an average with only a small portion of appropriate treatments (Priyank Hirani, 2019). The fast-developing of industrialization and a greater increase in farming growth combined with the new improvement as well as agricultural compost have increased the water pollution levels to a great degree (Geetha & Gouthami, 2016). Low water quality results have been known as the significant element of the rise in intolerable diseases (U. Ahmed et al., 2019). The major rivers like the Ganga, Yamuna, Godavari, Kaveri, Narmada of India are getting polluted due to the involvement of large industrial discharge, domestic products, and pesticides used in the farming field, which requires special treatment and attention (Aktar et al., 2010). The quality of water depends on the chemical, physical, and biological parameters. The major physical parameters include turbidity, water temperature, electrical conductivity, total dissolved solids, taste, and odor. The major chemical and biological parameters are the potentials of Hydrogen (pH), nitrates, Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), Chloride, bacteria, and algae, respectively. Accessing all the water pollutants from water sources is complex and time-consuming. Further, the huge set of data acquired after exploring all the samples and comparing it with the predefined rules is hard to handle (Iqbal et al., 2019). So, the Water Quality Index (WQI) measurement method has been considered, which can represent the total water quality in a single index (Iqbal et al., 2019). The WQI will give a comprehensive idea related to the water quality level. The traditional water quality monitoring technique is costly, slow-moving, tedious, and frequently produces manual errors. Moreover, it only permits examining a finite number of samples owing to a need for infrastructure and resources (Priyank Hirani, 2019). Hence, it is essential to develop advanced methodologies for observing and analyzing water quality. The main motto of this research work is to study different statistical and Artificial Intelligence (AI)-based models for efficient prediction and future forecasting of the WQI.