Document: NUREG-1555
Document ID: d196063a-7dbb-4b68-86d9-5aeb781a0655
Document Type: esrp
Title: HYDROLOGY
Source: NUREG-1555
Source URL: https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1555/initial/
Revision Date: 2007-10
Chapter: 2
Section ID: 2.3.1
CFR Part: 
CFR Title: 

Content:
cluding floodplain areas of offshore islands. This includes, at a minimum, that area subject to a 1% or greater chance of flooding in any given year. The base floodplain shall be used to designate the 100-year floodplain (1% chance floodplain). The critical action floodplain is defined as the 500-year floodplain (0.2% chance floodplain) (from Executive Order 11988, “Floodplain Management”). NUREG-1555 2.3.1-2 October 1999 Data and Information Needs The type of data and information needed will be affected by site- and station-specific factors, and the degree of detail should be modified according to the anticipated magnitude of the potential impacts and distance from the site. General, surface-water, and groundwater data and information should be obtained as described in the following sections. The following general(a) data or information should be obtained: ` maps (including digital databases such as a Geographic Information System [GIS]) of sufficient detail to show the relationship of the site to major hydrological systems that could affect or be affected by plant construction or operation (from the environmental report [ER] and the general literature) ` for surface-water bodies used as a heat sink, maximum, average-maximum, average, average- minimum, and minimum monthly temperature of the water body (from the ER and the general literature) ` for surface-water bodies and wetlands, estimated erosion characteristics and sediment transport, including rate, bed, and suspended load fractions, and graduation analyses; a description of the floodplain(b) and its relationship to the site; a description of wetlands and their relationship to the site; the design-basis flood (DBF) elevation; and, where applicable, the DBF discharge (from the ER and the general literature). Surface-water data and information to be obtained fall under three categories: freshwater streams, lakes and impoundments, and estuaries and oceans. The following data and information about freshwater