This book focuses on displaying and summarizing the representative results of the public welfare scientific research, public service and technical consulting projects undertaken by the Beijing Water Conservancy Research Institute (2011), including water environment, ecology and environment, rainwater utilization, water-saving technology, recycled water utilization, water engineering technology, water management, etc. It aims to realize that public welfare scientific research leads the development of water science and technology, public services support government decision-making, and technical consultation promotes the development of water science, and provides the latest scientific research information and technology exchange platform for water workers. This book can be used by scientific research, planning, design, and management personnel in water resources, water ecological environment, agricultural water conservancy, soil and water conservation, water conservancy and hydropower, and other majors. It can also be used as a reference book for efficient related majors.