Figure 1: Different vulnerability assessment parameter based on previous research
Catastrophic losses in terms of human casualties, property destruction, economic damages, and loss of public confidence could result from dam failure in the downstream and floodplain area. Traditionally, when man-made disasters caused by sabotage or terrorist actions, the risk is expressed as a function of the likelihood of an initiating event, the likelihood of system failure, and the consequences associated with the failure. There are different models for assessing the risk of a variety of assets such as Sandia series as RAM models for dams (D-RAM), RAMCAP, Security Vulnerability Assessment (SVA), CARVER + Shock, PHA, RVA, What If, FMEA, FMECA, MSRAM, SRFT, and KSM. Some of these methods are qualitative or semi-qualitative, and some of them are quantitative such as FTA and ETA (Biringer, Matalucci, & O’Connor, 2007; A. Doro-on, 2011; A. M. Doro-on, 2014; Hokstad, Utne, & Vatn, 2012). Some of these risk approaches are completely qualitative based on causes and consequences such as What If, PHA, and FMEA. The models such as FMECA or CARVER + shock emphasize criticality and exposure to the hazard. Some of the other approaches have selective techniques, but the comprehensive module is based on probability and consequence analysis, vulnerability assessment, and finally risk assessment such as RVA. Some of the other approaches are based on assumed parameters, which are rigid but simply such as an SRFT method. Another important factor in risk assessment is attractiveness, which is more comprehensive than exposure to the hazard. KSM model emphasis on attractiveness and it is developed based on strategies od Khalid Sheikh Mohamad (the designer of the 11 September attack). However, the other approach which covers threat analysis, asset analysis, attractiveness, and vulnerability assessment to achieve the risk number for each property is SVA. SVA is one of the comprehensive approaches, which is currently used in different sectors and infrastructures. One of the advantages of SVA is the flexibility of techniques that can be used in each part of SVA (Norman, 2016; van Staalduinen, Khan, & Gadag, 2016).
Dams as one of the superstructures are very important infrastructures of each country, especially while dams are dominant to the crowded areas to make the high-potential target for terrorist action (Danso-Amoako, Scholz, Kalimeris, Yang, & Shao, 2012). For instance, the Mosul dam which is the largest dam in Iraq became one of the tools of ISIS for threatening downstream cities during Mosul occupancy in 2016. On the other hand, dams have several advantages such as supplying water resources for potable water, agricultural activities, producing electricity, and controlling floodwaters. Thus, dams make the downstream area a growing population center inherently. Cities, industries, and farms start to grow up while environmental resources such as trees and woods are started to vanish. These factors highlight the vulnerability assessment and importance of risk analysis for dams especially based on downstream properties and assets. Several studies have been done in vulnerability assessment of areas that are under the effects of a flood caused by dam destruction. Messervey (2007) has created a framework and discovered modeling technique’s methods for dam destruction. Awal (2008) studied dam destruction caused by landslide and flyover increasing water height (Awal, 2008) and other studies described different alternative signals and decreasing floodwater risk (Persson, 2015).
As it was considered, most of the researches in this field tried to zone floodwater and the level of flooding in downstream areas caused by through the dam destruction, by using hydraulic software or crisis management under natural threats (such as earthquake, floodwater and…), but there isn’t any research to evaluate the accurate vulnerability of dam destruction assets based on hydraulic modeling in collaboration with water flow factors and destruction scenarios, particularly under man-made threat. Vulnerability assessment on infrastructures becomes a highlighted and suspected approach from homeland security agencies and even private sectors, which owned infrastructures or at least be one of the stockholders of that infrastructures. Vulnerability assessment is a part of risk assessment, which shows the dam or any investigated infrastructure how vulnerable to the identified threat. So, the vulnerability of infrastructure could be separated into three categories, which show the enhancement of three generations of assessment. In the first generation which is clear from early models such as FMEA, CORVER, RVA, etc.; the inherent properties of an asset become the main nutrition for assessment of vulnerability or even the risk assessment of the asset. In the next generation while the KSM method or SRFT considered the attractiveness and exposure to the hazard as the other main criterion of vulnerability, which was mentioned by Kröger and Zio (2011) too, besides asset property according to the vulnerability and risk analysis (Norman, 2016). Finally, the third generation is a triangulated approach based on asset property, attractiveness and dependencies, and interdependencies following the network of properties. Model-Based Risk Assessment (MBRA) is one of the integrated models developed by Lewis and Al Mannai in 2008 under third-generation (Mannai, 2008). The security Vulnerability Assessment (SVA) approach also considered attractiveness beside the criticality of properties. However, there is a necessity for a more scientific approach especially on behalf of hydraulic characteristics of flood and interaction between flood and downstream properties in the floodplain area while the destructive action is succeeded.
So, based on the latest vulnerability assessment generation a new hybrid approach should be developed that considers the vulnerability of the dam’s downstream area. Thus, this research aims to modify an integrated hybrid model to analyze the vulnerability of dam’s downstream assets due to man-made succeeded adversary threats to provide risk analysis and management and plan for protection or mitigation of the high-risk area. Figure 2 is showing the theoretical framework of this approach.