Water resources management and engineering principles are covered in the optional subject of Water Resources Engineering. This subject focuses on the planning, development, and management of water resources in order to meet various societal needs. It encompasses a wide range of topics related to water supply, irrigation, hydroelectric power generation, flood control, and environmental conservation. Here are some specific principles covered in this subject:

1. Water Demand Assessment: This principle involves the estimation of current and future water demands for various purposes such as domestic, industrial, and agricultural use. It includes techniques for assessing population growth, water consumption patterns, and factors influencing water demand.

2. Water Supply Systems: This principle deals with the design and operation of water supply systems to ensure a reliable and sustainable water supply. It covers topics such as sources of water, water treatment processes, storage and distribution systems, and water quality management.

3. Irrigation Engineering: Irrigation is a crucial aspect of water resources management, especially in agricultural areas. This principle focuses on the design, operation, and maintenance of irrigation systems for efficient water use and crop production. It includes topics such as types of irrigation methods, water conveyance structures, irrigation scheduling, and drainage management.

4. Hydroelectric Power Generation: Water resources engineering also includes principles related to hydropower generation. It covers the design and operation of hydroelectric power plants, including the selection of suitable sites, dam construction, turbine design, and power generation optimization.

5. Flood Control and Management: This principle deals with strategies and techniques for mitigating the impacts of floods. It includes the design and operation of flood control structures such as dams, levees, and flood diversion channels. It also covers flood forecasting, floodplain mapping, and emergency response planning.

6. Environmental Considerations: Water resources management principles also emphasize the importance of environmental conservation and sustainable development. It covers topics such as environmental impact assessment, water pollution control, ecosystem restoration, and integrated water resources management.

Overall, the optional subject of Water Resources Engineering provides a comprehensive understanding of the principles and practices involved in managing and engineering water resources. It equips students with the knowledge and skills to address the challenges of water scarcity, climate change, and increasing water demands in a sustainable manner.