**1. Introduction**

Flash floods are one of the most devastating natural disasters in the world, causing damage to properties, killing more than 5000 people every year, and registering the highest mortality rate among the other riverine and coastal flooding disasters [1].

Egypt is considered one of the countries that suffer from flash flood hazards and risk in mountains and nearby areas; every year, people, human activities, urbanized areas, and infrastructure are threatened by rainwater inundation. In the last few years, Egypt has experienced several flash flood events that caused serious damage and loss of lives, infrastructures, and buildings. The analysis of historical flash flood events over Egyptian land indicates that the eastern desert received highly destructive repetitive flash flood events starting in 1979 along El-Quseir and Marsa Alam, which killed 19 people and destroyed the coastal highway. The flash flood of Marsa Alam city, which happened in 1991 and caused big damage, the Alexandria city flash flood that killed 21 people in 1993, as well as a well-known flash flood that happened in 1994 and caused severe damage to infrastructure and loss of lives in Assiut governorate [2].

In October 2016, a devastating flash flood event struck Ras-Gharib city, killed dozens, and caused damage to infrastructure [3]. The Minya area has been affected by several flash flood events since 1975; heavy rainfall happened in Upper Egypt. It destroyed about 180 houses and displaced 1500 citizens [4]. In November 1997, a flash flood affected the area of study and killed 53 people, destroying 260 houses [4]. Recently, in March 2020,

**Citation:** Darwish, K. GIS-Based Multi-Criteria Decision Analysis for Flash Flood Hazard and Risk Assessment: A Case Study of the Eastern Minya Watershed, Egypt. *Environ. Sci. Proc.* **2023**, *25*, 87. https://doi.org/10.3390/ ECWS-7-14315

Academic Editor: Athanasios Loukas

Published: 3 April 2023

**Copyright:** © 2023 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

a heavy-rainfall flash flood struck the area, causing land subsidence and huge damage to the El Geish highway, infrastructure, and settlements as shown in Figure 1.

**Figure 1.** Photographs show the destruction of El Geish highway by the March 2020 flash flood. Source: https://www.youm7.com (Online Newspaper published on 14 March 2020).

The Geographic Information System (GIS) is an important technique that provides the capacity to design geospatial identities and analyze and manipulate spatial information. This information can be managed and organized through attribute tables. The tabulated data is linked to the geographic features, which may contain multiple quantitative and qualitative information.

GIS-based AHP calculations are very important in revealing spatial trends and relationships between geospatial data and retrieving valuable information for decision-making [5]. Multi-criteria decision analysis (MCDA) is a decision-making technique developed to make solutions to complex decision problems [6]. The GIS-MCDA uses the analytical hierarchical process (AHP) method for controlling and arranging the parameters to investigate complex decisions [7]. The GIS-MCDA method has the ability to process and combine different types of geospatial data (rainfall map, land cover, soil types, slope map, drainage density); results can be visualized and presented in maps [5]. It is a very important spatial decision tool for spatial planning and managemen<sup>t</sup> issues [8,9]. Integration of GIS and MCDA has been globally applied to assess flood hazards and risk assessment in Greece [6,10], Iran [7], Malaysia [11], Saudi Arabia [12], India [13], and Egypt [14].

### **2. Study Area**

The Minya area is located about 240 km south of Cairo city, the capital of Egypt, on the crossing of Longitude 31◦30 N, Latitude 28◦ E. The drainage basin selected for study has two large valleys (Wadi al-Tarfah and Wadi al-Bustan) crossing the limestone plateau. The mouth of the basin is situated in eastern Beni Mazar city in northeastern Minya city. The area of study extends to cover most of the eastern part of Minya governorate; it covers an area of 10,682.9 sq. km, as shown in Figure 2.

**Figure 2.** Location map of study area.

### **3. Materials and Methods**

Satellite remote sensing and GIS data were collected for this study to generate the flash flood hazard map based on the AHP technique, as shown in the flowchart in Figure 3. Six significant flood-controlling factors were selected based on the physical and natural properties of the study area, including elevations, slopes, soils, hydrology, land cover, geology, and rainfall. GIS-based MCDA has the ability to examine multi-criteria factors thematic maps using weighted overlaid analysis to assess the flash flood hazard map and risk along human activities [6,7].

**Figure 3.** Flowchart shows the MCDA method applied in this study.

The analytical hierarchy process (AHP) has been applied in this study to assess the flash flood hazard and risk in the watershed of the study area; spatial criteria used in this study come from geology, topography, rainfall, hydrology, soil, and land cover maps.

### *3.1. Lithological Data*

The Egyptian geological map of the study area scale 1:500,000 was digitized and analyzed to identify the lithological units, and three major geological formations were detected: (1) Quaternary deposits occupy 13.3% of study area, including sand sheets, wadi deposits, and gravels. (2) The Eocene limestone formation is covering 82.4% of the study area, including the Samalut, Minia, Maghagha, Observatory, Qarara, and Thebos Formations. In addition, (3) the Cretaceous formations cover 4.3% of study area, which include Rakhiyat, Galala, Sudr, Umm Omeiyed, Hawashiya, and Wadi Qena Formations, as shown in Figure 4. Geology is one of the main factors effecting in runoff due to the permeability of rocks and faults may increase the infiltration rate.

**Figure 4.** Geological formations of study area.
