Flood control and emergency response

Author: Chief Editor: Zheng Zheren et al
Publisher:
Publish Date: 2005-08-01
Features: This book consists of seven chapters. Chapter 1 Introduction briefly outlines the basic knowledge of flood control and emergency response for small reservoirs, the characteristics of flood control and emergency response, and the importance of flood control work. Chapter 2 Flood Control Organization and Responsibilities summarizes flood control policies, tasks, the responsibilities of institutions or dedicated personnel, and the establishment of flood control teams. Chapter 3 Flood Control Preparation and Inspection. Chapter 4 Emergency Response for Earth Dam Hazards discusses specific emergency response methods and precautions for issues such as seepage, leaks, collapses, slumping, piping, cracks, slippage, wind and wave damage, and slope protection damage in earth dams. Chapter 5 Emergency Measures for Rescue briefly covers increasing flood discharge in a timely manner, temporary measures to prevent flood overtopping, early warning systems, and flood forecasting and dispatching. Chapter 6 Emergency Response for Water Conveyance and Discharge Structures discusses specific emergency response methods for hazards in water conveyance tunnels, spillways, gates, and closing equipment. Chapter 7 introduces more than 20 case studies of emergency response for small reservoir hazards for reference in flood control and emergency response. This book is suitable for grassroots water management technical personnel and can also serve as a training textbook for county (city) water management departments.
Excerpt:
Section 1 Basic Knowledge of Flood Control and Emergency Response
1. Floods, Flood Season, and Flood Control
The term "flood" refers to periodic rises in water levels, caused by rainfall, snowmelt, or ice thaw, resulting in seasonal or cyclical flooding in rivers and lakes. Floods are often named after the season or cause of occurrence, such as spring floods, summer floods, ice jams, and tidal floods. Spring floods (or peach floods) are rises in water levels due to rainfall or snowmelt in river basins during spring. Summer or autumn floods are rises in rivers caused by rainfall. Ice jams, which occur only in northern regions, are rises in rivers due to ice blocking water flow. Tidal floods occur in coastal areas due to periodic rises in sea levels.
The term "flood season" refers to the period from the beginning of flooding to its recession in river and lake areas. Due to differences in geographical location, climate conditions, and rainfall seasons across various rivers in China, flood seasons vary in length, timing, and water volume. Even within the same river, flood seasons can differ each year, with varying start times and water volumes, and their progression is highly variable. To facilitate flood control efforts, China has designated flood seasons based on major precipitation patterns and river flooding conditions. For example, the Pearl River flood season is from April 1 to September 30, the Yangtze River from May 1 to October 31, the Huai River, Hai River, Liao River, and Songhua River from June 1 to September 30, and the Yellow River from June 1 to October 31.
The term "flood control" refers to defensive measures taken during the flood season to prevent or mitigate flood disasters, with the goal of ensuring the safety of reservoirs, dikes, and downstream areas. The main tasks of flood control include: patrolling and guarding flood control facilities such as rivers, reservoirs, dikes, and sluices; forecasting rainy weather and flood conditions; dispatching flood control facilities for storage, release, diversion, and retention; taking temporary emergency measures in extraordinary situations; and emergency rescue and flood disaster relief upon discovering hazards.
2. Hazards, Emergency Rescue, and Principles of Rescue
Hazards occur during major flood seasons or high water levels when water pressure, flow velocity, and wind waves increase, potentially endangering the safety of hydraulic structures due to insufficient height or strength, hidden defects, or flaws. Emergency rescue refers to urgent actions taken during high water levels or rapid water recession to prevent the escalation of hazards such as seepage, slippage, collapse, cracks, or scouring, thereby avoiding engineering failures. Flood control and emergency rescue are closely linked and mutually supportive. Only by effectively conducting flood control can hazards be avoided or minimized, and even if hazards occur, they can be addressed proactively and effectively to turn danger into safety.
The main principles of emergency rescue are:
① Timely rescue to prevent hazards from worsening, which requires strengthening inspections and observations to identify hazards early and act quickly to address minor issues.
② Accurately identifying hazards by understanding the design, construction, management, and operation of the engineering, combined with observed phenomena, to make accurate judgments and formulate correct rescue plans.
③ Ensuring timely supply of materials, as the types and quantities of materials needed for rescue directly impact the progress of rescue efforts.
④ Strengthening leadership and unified command to organize rescue teams, and, if necessary, requesting military support.
3. Reservoirs, Hazardous Reservoirs, and Reservoir Classification
Reservoirs are structures built in gorges or river valleys using materials such as earth, sand, gravel, or concrete to block streams or river flows, storing rainwater upstream to regulate natural runoff for flood control, irrigation, water supply, and power generation. Such structures are referred to as reservoirs. By regulating floods through reservoirs, downstream flood discharges can be reduced, alleviating flood disasters. At the same time, can be improved, achieving comprehensive benefits.