Flooding, hazards

Key words GIS, Floods, hazard assessment, risk assessment, dam breach, Hawaii... 

Table 1. The table of main roof flood hazards.

Operability and integrity of critical systems to control and recover from a flooding hazard. 

AR27 Flood hazard for nuclear power plants on coastal and river sites, NS-G-3.5, 18 March 2004. 

Provisions in the layout should be made early in the process of plant design as a valuable way of reducing P2. In this regard, feedback of experience from similar installations should be taken into account. Decisions on layout are of particular importance in relation to missiles and flooding hazards, and these considerations are addressed in the corresponding sections of this Safety Guide. 

In particular, as well as a break, a leak with a limited area should be considered to be a PIE that could lead to an internal flooding hazard. For flange connections and for different types of sealing, the possible leak areas should be analysed case by case. 

INTERNATIONAL ATOMIC ENERGY AGENCY, Flood Hazards for Nuclear Power Plants on Coastal and River Sites, Safety Standards Series No. NS-G-3.5, IAEA, Vienna (2003). 

Table 8.2. Generalized flood hazard zones and management strategies (after Kenny, 1990). With the kind permission of the Geological Society...

Flood hazard zone I (active floodplain area)... 

Flood hazard zone II (Alluvial fans and plains with channels less than a metre deep, bifurcating and intricately interconnected systems subject to inundation from overbank flooding)... 

Flood hazard zone III (Dissected upland and lowland slopes drainage channels where both erosional and depositional processes are operative along gradients generally less than 5%)... 

Kenny, R. 1990. Hydrogeomorphic flood hazard evaluation for semi-arid environments. Quarterly Journal Engineering Geology, 23, 333-336. 

States was formed in 1976. The major concerns that interest ASFPM include flood-hazard mitigation, flood-plain management, the NFIP, and just about anything else that involves flooding issues. 

Dunne, Thomas, and Luna B. Leopold. Water in Enm-ronmentalPlanning. New York W. H. Freeman, 1978. A classic text in the water field contains useful information regarding runoff processes, flood hazards, and human occupancy of flood-prone areas. 

Abstract This chapter presents a stochastic optimization model for disaster management planning. In particular, the focus is on the integrated decisions about the distribution of relief supplies and evacuation operations. The proposed decisionmaking approach recommends the best relief distribution centers to use as storage locations and determines their optimal inventory levels. The model also incorporates the priorities for the evacuation of particular communities, as well as specific disaster scenarios with estimates of the transportation needs and demand for aid. A case study is presented to determine the distribution of aid for a flood emergency in Thailand that uses a flood hazard map. 

Using our stochastic approach, we used the flood hazard map for Chiang Mai to generate disaster scenarios that closely match real floods in this area. We considered seven different scenarios, and their probabilities of occurrence are calculated from historical data for the past three decades 0.35,0.20,0.18, 0.12, 0.08,0.05, and 0.02 for scenario 1-7, respectively. Each of these scenarios creates a different demand for relief, depending on how much of the area is affected. 

Fig. 2 Seven levels of Chiang Mai flood hazard map (CENDRU 2015)...

This Safety Guide provides recommendations on how to meet the requirements established in the Safety Requirements publication on Site Evaluation for Nuclear Installations [1] in respect of the flood hazard to be used in site evaluation for nuclear power plants on coastal and river sites. Measures for the protection of nuclear power plant sites against floods and the strategy for monitoring sites are also discussed. 

Hiis Safety Guide is the first revision of and supersedes two Safety Guides dealing with flood hazards on river sites and on coastal sites respectively and originally issued under the IAEA s safety standards programme in 1983. ... 

The purpose of the present Safety Guide is to provide recommendations relating to the evaluation of the flood hazard for a nuclear power plant on a coastal or river site so as to enable the identification of hazardous phenomena associated with flooding events initiated by natural and human induced events external to the site. 

This Safety Guide discusses the applicability of different methods for the evaluation of the flood hazard. Dam failures, tsunamis and other very rare events may generate a flood substantially more severe than floods due to precipitation. Generally, very few historical data are available and special techniques have to be developed. The static and dynamic effects of floods resulting from various combinations (independent and interdependent) of surface waves of differing frequency are also discussed. Consideration is also given to the effects of shoreline instabilities and erosion. 

Section 13 deals with measures for the protection of the site from floods and flood induced events. Section 14 deals with specific mechanisms for periodic review of the flood hazard for the possible effects of modified site conditions and global warming. Section 15 deals with the monitoring of flood related initiating causes and their effects. 

The design basis flood has to be derived from the flood hazard for the site, which is a probabilistic result derived from the analysis of all the possible flooding scenarios at the site. However, in some cases the design basis flood is evaluated via deterministic methods and no probability is attached to it. In these cases a probabilistic evaluation should always be carried out to be able to compare the contributions of different design basis scenarios to the overall plant safety (see Ref. [6]) and to evaluate the overall probability of radiological consequences of a potential plant failure. 

For coastal sites (sea, lakes and semi-enclosed water bodies) the flood hazard is related to the most severe among the following types of flood, where apphcable ... 

For river sites the flood hazard is associated with one or more of the following scenarios ... 

In general, the flood hazard should be compared critically with recorded and historical data and the design basis flood should be set at a value not less than a recorded occurrence plus a substantial margin that should be related to the length of the period over which measurements were made and the local situation. This should only be done provided that there has been no significant change in the basin either upstream or downstream of the site. 

A dam failure or tsunami, where applicable, may generate a flood substantially more severe than any due to natural meteorological phenomena. For these cases the site specific methods outlined in the subsections should be used to estimate the order of magnitude of the flood hazard. 

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