D24

Hydrological Modelling of Flash Flood at the UNESCO World Heritage Site Petra, Jordan○Omar M. Habiba, Mohamed Saber, Sameh Kantoush, Tetsuya Sumi

Abstract
Wadi flash floods in the Middle-East-North-Africa (MENA) region are considered as one of the mostcatastrophic phenomena possessing hazardous threat to the coastal cities and infrastructures, and human lives aswell as the UNESCO World Heritage Sites (WHS). As it was seen in November 2018 and April 1963 in theUNESCO WHS Petra in Jordan, flash floods pose a serious threat to the lives of the tourists and the locals living
there as well as the monuments themselves. Despite the advanced technology that exist nowadays, there is an
obvious lack of mitigation measures in Petra catchment such as check dams, vegetation, diversion channels andterraces. This study aims to apply the 2-Dimonesional Rainfall-Runoff-Inundation (RRI) model on the catchment
to simulate different extreme events scenarios. Moreover, it aims also to develop and come up with the optimum
flash flood mitigation measures that can be implemented at Petra to reduce the flash flood risk on the tourists andthe locals as well as the monuments at Petra. The RRI model was adapted to simulate different flood events and toestimate their impacts on flood peakflow, inundation and runoff volumes. Several field surveys have already been
conducted and some appropriate sites for some mitigation measures such as dams can be built based on thegeomorphological features as well as inundation areas and the hydrological conditions. Using the hydrologicalmodel, dams as well as other mitigation measures such as diversion channels, terraces and afforestation are going
to be estimated in the hydrological model. The results of mitigation measures impacts on flood peakflow and volume
as well as the inundation in the area are going to be represented. Due to climate change, the risk of flash flood isincreasing, especially in the MENA region. Therefore, the study is a way forward to promote the awareness as wellas to propose possible flash flood mitigation measures in theMENA region.
Introduction
Many natural disasters affect the MENA
region such as drought and flash floods. The intensityof such disasters became more frequent in the lastdecade. Climate Change could be the driving force ormaybe it is just due to increasing media coverage. In
this study, the focus is on the ancient city of Petra inJordan. As shown in Figure 1, Jordan is located in theheart of Middle East, a strategic location that gave thecountry a prestigious role throughout history to bepart of the ancient world and made it one of the mostimportant ancient routes in ancient history.
Consequently, many civilizations such as theNabatean civilization were based there and carved
their own city, Petra. Petra is one of the mostimportant and famous attractions, not only in Jordan,
but in the entire world. In 2007, it was voted as oneof the “New 7 Wonders of the World”. It is located inthe south of Jordan, Petra is the major site withantiquities dating back to 7500 BC(Al-Weshah andEl-Khoury 1999). The site plays a very important rolein the tourism of Jordan. The tourism in the country
is a major contributor to the national economy.
Historical records and other events related toflash floods threatening Wadi Musa and Petra have

Figure 1: Detailed map of Petra showing the wadis in thecatchment, the rainfall stations, the stream network, and the dams

shown that flood protection and mitigation measures
are urgently needed in order to protect the monuments,
the locals and the tourists. Such measures should beimplemented after a hydrological assessment andanalysis considering the unique nature of the area.
Methodology

as its resolution, 4km, which was better than GSMaP
data’s resolution, 10 km. The validation of the RRI
model was done based on the calibrated RRI model,
the corrected PERSIANN-CCS data and the water
depth level recorded by the Petra Development andTourism Regional Authority (PDTRA). The locationsof the dams were chosen during on the field campaign
based on the geomorphological features and thehydrological conditions of the selected areas.
Results and discussion

Figure 2: Flow Chart of the Methodology for RRI model

Rainfall-Runoff-Inundation Model (RRIModel) has been applied for flash flood events inPetra Catchment after its calibration andvalidation(Sayama, Ozawa et al. 2012; ABDELFATTAH, KANTOUSH et al. 2016). Floodsimulation was performed based on daily time series
rainfall data because of the lack of hourly observed
data. For the channel cross-sections settings, twolocations were used: one in the upstream in Wadi
Assadir and the other one is downstream next to thearchaeological park entrance in addition to Google
Earth Images to estimate the channel width and depth
parameters area information were W=CW ASW and
D=CD ASD(CW= 2.86, Sw= 0.449, CD= 0.766 and SD=0.413). The rainfall and the peakflow records for theevents in 1968, 1970, and 1974 were used for thecalibration(Al-Weshah and El-Khoury 1999)(. The
model was calibrated by using each of the three
events and validated based on the other 2 ones. Themajor sensitive RRI model parameters setting byassigning case-a to Urban and Sandstone, case-b toLimestone and case-c to Vegetation. Figure 2 shows
the methodology of the application of the model. Firstthe topographic data were obtained by using ALOSPALSAR 12.5m DEM data. The flow direction andflow accumulation using ArcMap 10.6.1. Moreover,the land use map was developed using theclassification of sentinel 2B satellite image using
ArcMap. Regarding the rainfall data, the observed
daily data were obtained from 3 different stations
distributed around the catchment. There were a lot of
missing records in the data. Therefore, it was better touse satellite data. However, in order to use thesatellite data some bias correction needed to be done
(Lafon, Dadson et al. 2013). In this case, the linear
correction method was used. A comparison was madeto choose which satellite data should be utilized in thearea. PERSIANN-CCS was chosen since it has better
performance to record the rainfall in the area as well

It was found that the water level records usedin the Early Warning System EWS are not reliable at
all and their corresponding hourly rainfall data had tobe treated first. The R2 of the GSMaP data was lower
than the R2 of the PERSIANN-CCS. Therefore, thelater one was chosen for the bias correction. It was
found that the PERSIANN-CCS data isunderestimated in the study area by 56%. The bias
factor obtained is 2.23. Regarding the calibration ofthe RRI, Table 1 shows the results of the simulation
used in the events chosen for the calibration.
Table 1: Results of the calibration of RRI modelDailyRainfall
1
1.79
1.53
212
2.18
2.58
46.1
30.41
0.36
15.7
Regarding the validation of the RRI model, the model
showed a good performance in simulating the recent
events: January & February 2013, November 2013
and November 2018.
Eventobserved

simulated

Conclusion
The RRI model showed a great performancein simulating the extreme events in Petra. It showedalso that such mitigation measures in the area areneeded. Moreover, the rainfall stations in the areas
need to be checked and maintained from time to time.
Despite the importance of the area, there was only onehydrological study that has been done on the area in1999. This study is a recent study that considers thenew technics that can be utilized as well as theimportance of the implementation of such mitigationin the study area.
References
ABDEL-FATTAH, M., S. KANTOUSH, et al. (2016). "Hydrologicalmodelling of flash flood at wadi samail, Oman."
Al-Weshah, R. A. and F. El-Khoury (1999). "Flood analysis andmitigation for Petra area in Jordan." Journal of Water
Resources Planning and Management 125(3): 170-177.
Lafon, T., S. Dadson, et al. (2013). "Bias correction of daily
precipitation simulated by a regional climate model: acomparison of methods." International Journal ofClimatology 33(6): 1367-1381.
Sayama, T., G. Ozawa, et al. (2012). "Rainfall–runoff–inundation
analysis of the 2010 Pakistan flood in the Kabul Riverbasin." Hydrological Sciences Journal 57(2): 298-3120