Hydrology is a science that examines the origin, circulation and distribution of water in nature, the physical and chemical properties of water, the reactions of water in the environment and its relationship with living organisms. This science is particularly important because water is a vital and strategic resource that affects all aspects of sustainable development, economy, health, security and culture. Hydrology enables us to manage water resources optimally and responsibly, provide scientific solutions to problems caused by shortages, pollution, floods, droughts, and climate change, preserve and enhance natural defenses, and maintain the health of aquatic ecosystems. It also helps to protect biodiversity and public interest. Using experimental, theoretical and numerical methods, hydrologists collect, analyze and model various data to identify, answer and project hydrological phenomena. Hydrologists also collaborate with other disciplines in the earth sciences, social sciences, medical sciences, computer sciences, and information technology to answer research questions.
Hydrology is one of the quality indicators of the environment that indicates the health level of an area. Water quality is influenced by human activities and natural factors. Some of the water quality factors are: temperature, pH, electrical conductivity, dissolved oxygen, dissolved solids, suspended solids, nitrogen, phosphorus, heavy metals, bacteria and toxins. Decreasing water quality leads to a decrease in the efficiency of water resources for drinking, industry, agriculture and wildlife protection. Therefore, it is necessary to monitor the quality of water and implement standards and laws for the protection of water resources.