1 General Provisions
1.0.1 This standard is formulated for meeting the flood control requirements and guiding the construction of flood control pro¬jects in various regions and sectors of the national economy, and protecting the lives and properties from being flooded.
1.0.2 This standard is applicable to the planning, design, construction, operation and management of flood control, regard¬ing, protecting various flood protection objects against rainstorm flood, snowmelt flood, combined flood of rainstorm and snowmelt, and flood tide in estuaries and coastal areas. The flood protection objects include flood protection areas, industrial and mining enterprises, transport infrastructure, power facili¬ties, environmental protection facilities, communication facili¬ties, cultural relics and historic sites, tourism facilities, and wa¬ter resources and hydropower engineering.
1.0.3 The flood control standards for various flood protection objects shall comply with provisions stipulated not only in this standard but also in the prevailing national standards.
2 Terms
2.0.1 Flood protection object
It refers to an object that is threatened by floods (including flood tide) and needs to be protected.
2.0.2 Flood protection area
It refers to an area that may be inundated by floods (inclu¬ding flood tide) and needs to be protected by flood control infra¬structure.
2.0.3 Grade of flood protection
In order to facilitate the determination of appropriate flood control standards based on the sizes or properties of the objects requiring protection, flood protection objects of the same type are classified into several grades according to certain characteris¬tic indicators from the perspective of flood control.
2.0.4 Equivalent economic scale
Equivalent economic scale is the product of gross domestic product (GDP) per capita index and total population of the flood protection area.
2.0.5 Probable maximum flood
Probable maximum flood (PMF) refers to the theoretical maximum flood that may occur within a given duration upstream of a design river section. It is derived from hydro-meteorological principles and methods.
3 Basic Requirements
3.0.1 The flood control standards for flood protection objects shall be expressed by a recurrence interval of flood or flood tide. For flood protection objects of significant importance, the PMF may be adopted as the flood control standard. According to the requirements of different flood protection objects, design flood standards alone or both design flood standards and check flood standards may be adopted.
3.0.2 The flood control standards for various flood protection objects shall be determined through comprehensive analysis and validation, according to the flood control requirements of the economy, society, politics and the environment, and in consider¬ation of the relationships between the local and overall interests, the short and long terms, the upper and lower river reaches, the left and right river banks, the main streams and tributaries. If possible, the flood control standards should be rationally deter¬mined through comparative analysis of the potential reduction of economic losses from flood disasters and the corresponding flood control cost of different flood control standards.
3.0.3 When a certain flood protection area may be threatened by floods from different rivers, lakes or oceans, the corresponding flood control standard should be determined respectively according to the flood disaster severity of the river, lake or ocean floods.
3.0.4 When the required flood control standard for a flood pro¬tection object within a flood protection area is higher than the standard for the area and the flood protection object can be pro¬tected individually, the flood control standard for the flood protection object shall be determined individually, and separate protection measares shall be taken.
3.0.5 When there are more than two types of flood protection objects within a flood protection area, and they cannot be protected individually, the higher flood control standard between the flood protection area and the main protected objects shall be adopted as that for the flood protection area.
3.0.6 For a flood protection object affecting public flood control security, the higher flood control standard between the flood protection object and public flood control security shall be adopted.
3.0.7 For road subgrades, walls and other buildings/ structures with flood control function that are included in the flood control engineering planning, the higher flood control standard between the flood protection area and the buildings/ structures shall be adopted.
3.0.8 For the following flood protection objects, their flood control standards may be raised or lowered appropriately through validation:
