The Role of Remote Sensing Techniques in Flood Monitoring

1
The Role of Remote Sensing Techniques in Flood
Monitoring Aqaba Flash Flood Case Study part1
Royal Jordanian Geographic Centre Remote Sensing
Section
Prepared by Geo. Maria Khirfan
Geo. Tareq Al-Shawabkah
Presented by
Tareq Al-Shawabkah
2
Introduction

• Floods are among the most frequent and costly
  natural disasters in terms of human hardship and
  economic loss. About 90 percent of the damage
  related to all natural disasters is caused by
  floods and associated debris flows.
• The mapping and monitoring of floods are
  therefore important to the population living and
  working in flood-prone areas.
• Accurate, rapid and economical methods are needed
  to provide the data necessary for planning and
  management functions in order to prevent such
  disasters.

3
Main Objectives

• Highlighting on the Aqaba flash flood event that
  took place February 2006.
• The importance of remote sensing and satellite
  imagery in flash flood monitoring and management.
• Attempting to put down future proposed outlines
  for the establishment of a Flood Management Unit
  in collaboration with the different related
  sectors.

4
Remote Sensing and Natural Disaster Management

• Remote sensing and GIS provides a data base for
  disaster management in order to produce hazard
  maps, indicating which area is potentially
  dangerous.
• Using remote sensing data, such as satellite
  imageries with its large synoptic overview,
  allows us to map the variability of terrain
  properties, and obtaining the needed analysis.
• Remote sensing also allows monitoring the event
  during the time of occurrence.
• Remote Sensing can assists in damage assessment
  monitoring and flood mapping in order to provide
  a quantitative base for relief operation.

5
Flash Floods

• Flash floods are local floods of great volume and
  short duration. A flash flood generally results
  from a torrential rain or "cloudburst" on
  relatively small and widely-dispersed streams.
  Runoff from the intense rainfall results in high
  flood waves.
• It occurs within six hours of a rain event and
  depends on rainfall intensity and duration. Also,
  topography, soil conditions and land cover play
  important roles.
• Flash floods are particularly common in
  mountainous areas and desert regions but are a
  potential threat in any area where the terrain is
  steep, surface runoff rates are high, streams
  flow in narrow canyons, and severe thunderstorms
  prevail.

6
Major Recorded Global Flood Events Dartmouth
Flood Observatory
7
Aqaba Flash Flood

• Jordan recently has experienced a major flash
  flood which occurred in Aqaba city, in February
  2006. As a result of this major event and due to
  the great damages that was caused by the flood,
  this presentation came to shed the light on the
  main Aqaba flood, its causes and effects and the
  importance of flood management and warning system
  using remote sensing and GIS technologies.
• Aqaba is considered as one of the big residential
  cities in Jordan, an important industrial complex
  for several heavy industries, free trade zone
  area and tourism attraction city in terms of its
  unique natural property specially that of its
  marine life.

8
Location of the Study Area

• Aqaba city is located in the southern part of
  Jordan on the northern end of Gulf of Aqaba/Red
  Sea and forms the only seaport serving the
  country.
• It is bounded by 34 57' 0.6"-35 09'28.1"E,
  29 19'35.5"-29 43'57.9"N on the geographic
  co-ordinate system.

Study Area
Gulf of Aqaba
9
Climate of the Study Area

• The study area is best described in terms of its
  climate as arid while max. annual precipitation
  values do not exceed 50 mm in the best conditions
  and are restricted to the winter season, the
  potential pan evaporation is estimated 4100
  mm/year.
• Thunder storms do occur in winter and create run
  off and then rapid surface flash floods. These
  are the responsible factors for the occurrence of
  recent wadi shapes within the deposits along the
  coastal area.

10
Main Morphological Features of the Study Area
1. Granite Zones
3D Landsat ETM merged with IRS 5m
2. Side Wadis and Wadi Deposits
3. Alluvial Fans
4. Flood Plains
5. Coastal Wadis
6. Coastal Zones
11
Side Wadis and Wadi Deposits

• These wadis run from north to the south along the
  eastern part of study area within the granite
  series.
• Wadi Al Yutum is the biggest one in terms of its
  length and catchment area, and accordingly its
  capacity to transport clastics deposits. Its
  width ranges from 500-300 meters.
• Their sediments form the flood plains where the
  city locates. The major slope direction of these
  flood plains is towards the Gulf of Aqaba.

12
Geology of the Study Area

• The most southern part of Wadi Araba starts to
  slope towards Aqaba city from the area of Al
  Risha about 75 km north of Aqaba. It forms
  the wadi plain about 16 km wide at the end of
  Wadi Al Yutum. The Gulf of Aqaba occupies these
  plains and receives its products of floods.
• The area is generally covered by Quaternary
  sediments consisting of a stream type of
  alluviums with a valley fill type of sediments in
  the lower part of the basin.

13
Hydrology of the Study Area

• The average total amounts of rainfall during the
  rainy months of the year in Aqaba do not exceed
  50 mm.
• Rare frequent thunder storms sweep the area
  carrying casual intense precipitation in these
  rainy months resulting in total annual rainfall
  exceeding the previously mentioned value.
• Meanwhile, side wadis possess relatively wide
  surface watershed areas. They have extensions in
  areas where the annual rainfall is more than that
  of the Aqaba area. The high elevated granite
  mountains receive more amounts of precipitation
  due to their elevation. Accordingly the floods
  come from the eastern part along the alluvial
  fans especially during thunder storms, and form a
  risk. Therefore, the barren impermeable rocks and
  steep slopes of the highlands provide good
  conditions for runoff.

14
Spatial Distribution of Rainfall

• The analysis of the daily rainfall data of the
  last 20 years (1980-1999) indicates that under
  normal precipitation the daily rainfall doesnt
  exceed about five millimeters per day.
• But under the occurrence of thunder storms these
  can approach values of around 15 mm/day.

15
Runoff

• The most important property of the catchment in
  respect to runoff is the soil cover, its depth,
  permeability and slope.
• The analysis of satellite images indicate that
  erosion features as a result of floods and runoff
  are more concentrated in areas located directly
  downwards of side wadis, which receive the flood
  water from the elevated granite mountains
  catchments.

16
Methodology

• Geo-coded Landsat imagery of 30 meters resolution
  was merged with IRS imagery of 5 meters to obtain
  better spatial resolution.
• Digital Elevation Model was extracted from the
  1/50,000 contour lines.
• Drainage system and catchment area was produced
  from the obtained DEM.
• Superimposing the DEM layer over the satellite
  image to produce the 3D-View for the study area
  in order to obtain further analysis.

17
3D Landsat ETM merged with IRS 5m Aqaba City
DEM
2D Merged Image 5m
3D Merged Image
18
Wadi Al Yutum Catchment Area and Drainage System

• Wadi Al Yutum possesses the largest watershed
  area of about 2200 km² and the largest drainage
  system.
• Wadi Al Yutum extends to the north where higher
  rainfall averages and lower actual evaporation
  rates are found. The total surface flood upon
  this catchment area is about 1.5 million m³/y.

19
Digital Elevation Model Analysis of the Study
Area

• The Digital Elevation Model which covers the
  study area allows reflecting all the surface
  features. GIS modeling on the elevation data is
  important in mapping any region for many
  purposes, such as, slope, surface watersheds,
  topographical shapes.
• The general regional topographical trend of the
  study area is a north-south directed graben,
  bounded by two major flanks of higher elevations
  and cut with east-west directed wadis.
• The study area doesnt possess extreme elevations
  in the floor of the graben. The elevations start
  from values approaching zero nearby the sea zone,
  and start to increase gently to reach in the
  upper part of Wadi Al Yutum within the study area
  more than 1000 meters above sea level.

20
Main Factors Influencing the Aqaba Flood

• - Steep rigorous terrain
• - Steep slopes
• - High elevated mountains
• - High surface runoff
• - Narrow canyons
• - Wide surface watershed areas
• - Barren impermeable rocks
• - Severe thunderstorms
• - Large alluvial fans and flood plain

21
Main Factors Influencing the Aqaba Flood

• - Alluvial Fans

22

• - Big differences in elevation

A
Elevation of Area (A) 1400m Elevation of Area
(B) 20m
B
The granite mountain series has a slope ranges
about 20 to 60.
23
Aqaba Flash Flood Damages

• Aqaba suffered a severe water shortage crisis as
  a result of damage sustained by the main pipeline
  during the recent flash floods.
• The flash floods, killed nine people, injured 25
  and damaged houses and resulted in the loss of
  shelter and livelihood as well as damaging the
  water, electricity and transportation
  infrastructure.
• The new Aqaba Water Treatment Plant was damaged,
  where mud and rubble flowed into the rooms
  housing the electric pumps. Estimated damages to
  the facility at about JD2 million.

24

• Also, various sections of the pipeline conveying
  water to the Aqaba Governorate from the Disi
  reservoir were also damaged.
• Several sources predicted that Aqaba's
  industrial, commercial and tourism sectors would
  incur millions in losses as a result of the water
  disruption.
• In addition to, runways of the King Hussein
  International Airport were blocked with rubble
  and mud deposited by the floodwater.
• Main as well as side-roads were also blocked in
  the governorate.

25
Aqaba Flash Flood
Airport
Port
26
Major Floods (1963-2006) Showing the Hazardous
Flood Prone Areas in Jordan
Mufrag
Zerqa
Amman
Madaba
Karak
Tafela
Petra
1963
1965
Maan
1966
1987
1991
Aqaba
1994
2006
27
Number of Flood Events Casualties in Recent
Years
28
Natural Disaster in Jordan from 1927-2002

Percentage of people affected by disaster type
Percentage of people killed by disaster type
Flood 7
Earthquakes 42
Flood 53
Wind Storm 3
Extreme Temp 3
Drought 93
29
Conclusions

• As a result of the recent flash flood that
  occurred in Aqaba city and the previous floods
  that had affected other flood prone areas in the
  past, a Flood Management Unit should be
  implemented to produce a national plan for flood
  management that enables sustainable water
  resources and feasible agricultural development.
• The development of the data base requires the
  collection of accurate and reliable data on the
• - flooded area
• - depth and duration of flooding
• - damage caused
• - estimated repair and/or rehabilitation
  costs.

30
Conclusions

• Furthermore, a GIS analyses data and displays the
  results. It creates new information by combining
  data where this information can be a predictive
  modeling of a city's economic loss by analyzing
  the interaction of
• -         Flood depth, duration, and extent
• -         Agriculture systems
• -         Population characteristics
• -         Public infrastructure
• -         Economic conditions.

31
Proposed Local Model of Early Warning and Flood
Management Unit in Jordan

• The proposed Flood Management Unit should be
  composed of the following public sectors
• - Civil Defense Directorate
• - Ministry of Water and Irrigation
• - Meteorological Department
• - Local Communities and Municipalities
• - Royal Jordanian Geographic Centre

32
Thank You For Your Attention