3　Hydrologic Survey

3.1　General Requirements

3.1.1　Field hydrologic survey shall be conducted before other engineering hydrology works for nuclear power plant，no matter whether measured hydrologic data for the site is available or not.

3.1.2　The objectives，requirements，scope and content of survey shall be determined beforehand according to the engineering task.A list of data to be collected and content of survey shall be developed.

3.1.3　Reconnaissance surveys，interviews，necessary tests and data collection from local water conservancy，oceanic，planning，environmental protection，transport and other authorities shall be conducted to identify the variation characteristics of hydrologic elements.

3.1.4　The major survey content includes investigations on flood，source of fresh water，scour and silting of river banks，seashore，riverbed and seabed，landslide，collapse，debris flow，tide，wave，sea current，sediment，water temperature，storm surge，seiche，tsunami，rainstorm，ice condition，snow and other conditions that may affect the project.

3.1.5　The land flood survey and low-water survey shall cover vertical sections，cross sections，flood（lowwater）mark elevations，current water level，talweg or longitudinal slope of the main channel in the entire river reach to be surveyed.The survey points shall be such arranged that changes in water level and river sections can be revealed.

The sea survey shall cover high（low）tidal level marks，current tidal level and elevations of varied points along the shoreline.The scope of survey shall cover the entire sea area under consideration.

3.1.6　Reconnaissance survey results shall be completely recorded.Survey data shall be sorted out，analyzed，and verified on site，and corrected in the case of any problem.A report or an instruction shall be compiled after the survey.