F. Kuhn 14 January 2020
Environment of a Railway project in Saudia Arabia Republic
1. Natural environment
Saudi Arabia is one of the world’s hottest and driest places, climate can be characterized as a
desert’s climate, the coastal regions show a marked change of climate from that found in the
rest of the country. Nevertheless there is a cool and rainy short period in winter. Winter is
warm in most of the country, with high temperatures around 20°C, and cool in the mountains,
where the temperatures may fall below freezing at night. Polar air masses that occasionally
blow south from Russia can bring some truly cold weather: also between the night and the
day temperatures, we record wide fluctuations so we can find differences until 45°C.
Temperature can be cooler in some areas like near the sea.
Summer is very hot throughout the country and lasts from May to November. There is
generally no rain. In most of the country the highs are around 40°C. Some places are extremely
hot, with temperatures often rising above 50°C.
Source : http://www.myweather2.com/City-Town/Saudi-Arabia/Dammam/climate-profile.aspx?month=10
These high temperatures oblige the builders to take care of the quality of trackside
equipments installed along the track and in the technical rooms and also in the rolling stocks
and the workshops. Expansion joints should take into account these differences in
temperature and be installed in the track according to the standards. During the construction
of bridges and hydraulic structures, concrete pouring will be implemented early in the
morning and protected from too rapid drying to avoid premature shrinkage cracks.
It rains so rarely in Saudi Arabia that cities lack infrastructure to deal with heavy rain. The rain
sewers and drainage canals are lacking to deal with a torrent.
Rain is generally scarce, and most of it, originates in the Mediterranean region. In the desert
regions rainfall can vary greatly from month to month and year to year. Some places go years
without seeing any rain. Rain, when it does come, arrives in the form of deluge in fierce, short-
lived storms. Riyadh, and the barren deserts in the south and east get between nothing and
13 cm of rain a year. Rain is mostly likely to fall in February, March and April in Riyadh; and
December, January, February and March in eastern Saudi Arabia. The highest rainfall amounts
occur on the western slopes of the coastal mountains. Some places here have average annual
rainfalls is above 50 cm a year.
The coastal areas of the Red Sea and the Persian Gulf can be as oppressively humid and as
they are oppressively hot. In other places the air is often hot and dry during the day and damp
Source : http://www.saudi-arabia.climatemps.com/
The weather statistics displayed above represent the mean value of each meteorological
parameter for each month of the year. The sampling period for this data covers 30 years from
1961 to 1990.
Dhahran is located at short distance west of downtown Khobar. It is about 15 km in south of
Dammam where there is the railway of our line 1 under assessment. Both are older Saudi port
cities on coast of the Persian Gulf.
Dhahran’s climate is characterized by extremely hot, humid summers, and cool winters.
Temperatures can rise to more than 50 °C in the summer, coupled with extreme humidity (85-
100 per cent), given the city’s proximity to the Persian Gulf. In winter, the temperature rarely
falls below 2 °C or 3 °C, being the lowest ever recorded -0.5 °C in January 1964, with rain falling
mostly between the months of November and May. On July 8, 2003, the dewpoint was 35 °C
while the temperature was 42 °C, resulting in a heat index of 78 °C.
Source : Hong Kong Observatory in Wikipedia http://en.wikipedia.org/wiki/Dhahran
Cities, such as Jiddah and Makkah, are on low ground and are surrounded by mountains: when
rains fall on these mountains, water runs in valleys towards these cities. With poor drainage
systems, this continuous flow of water could easily lead to a flash flood.
So floods become natural disaster in Saudi Arabia: they have been the cause of 7 of the 10
most damaging natural disasters in the history of the country between 1900 and 2010.
In the case of the project of railway line 1 between Dammam and Riyadh, we found the floods
of 2005 (700 people evacuated, 700 people homeless) and 2010 in Riyadh (275 car crashes)
(cf. Yassar A. Alamri).
Source : http://www.myweather2.com/City-Town/Saudi-Arabia/Dammam/climate-profile.aspx?month=10
The right of way of the line 1 is for some sections surrounded by hills and sometimes its profile
along the line is excavated below the level of the surrounding ground: culverts are built under
the platform of the second track in progress and connected to culverts already made under
the first track under operation: an hydraulic study should verify if during a heavy rain, natural
basins in place or to be achieved can avoid flooding of the railway platform and damage until
a train derailment.
The wind (shamal)
The Shamal winds usually blow across the city of Dammam in the early months of the summer,
bringing dust storms that can reduce visibility to a few metres. These winds can last for up to
The average daily wind speed in last October has been around 13 km/h or 7 knots. In recent
years the maximum sustained wind speed has reached 56 km/h or 30 knots
!The knot is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph.
The chart below plots the average daily wind speed you can expect for any month. It also
shows the maximum, recorded sustained wind speed for each month.
Source : http://www.windfinder.com/windstats/windstatistic_dhahran.htm
The figure below shows that the mean speed of wind is around 15 km/h but it can rise to 90 to
96 km/h and then the conditions for sand’s storm are met.
A dust storm or sand storm is a meteorological phenomenon common in arid and semi-arid
regions. Dust storms arise when a gust or other strong wind blows loose sand and dirt from a
dry surface. Particles are transported by saltation and suspension. It is a process that moves
soil from one place and deposits it in another. As the force of wind passing over loosely held
particles increases, particles of sand first start to vibrate, then to saltate. As they repeatedly
strike the ground, they loosen and break off smaller particles of dust, which then begin to
travel in suspension. At wind speeds above that which causes the smallest to suspend, there
will be a population of dust grains moving by a range of mechanisms: suspension, saltation
We see in the figure about the wind speed above that the mean speed of wind is low and not
a hazard for operating trains. The recorded maximum wind speed is under 100 km/h that is
not also a hazard for operating trains but they must slow down their speed because visibility
is also decreasing as the sand ‘s storm is increasing with the wind’s speed.
Aggression of sand on railroad
In most parts of Saudi Arabia, geo-morphological processes are marked by the movement of
sand and dust, which has reached alarming proportion in recent years for various man-made
reasons. Overgrazing by camel and cattle has reduced bushes. Rock crushing, bulldozing,
grading, trucking and camel trailing have lost top surfaces and thus accelerated sand and dust
movements. As a consequence, built structures are abraded, building materials and utility
structures are corroded; walls, columns and poles are pitted, fluted, grooved and are exposed
to corrosion; communication poles are sand blasted; glasses lose transparency; painted
surfaces get damaged; mechanical equipments are worn; visibility is reduced; communication
is disrupted; eyes and throat are infected; food is contaminated; animals are often suffocated
and vehicular accidents are increased. In short, built-up areas are adversely affected and
human safety is badly endangered.
Massive deposition of sand and dust causes substantial coverage and often complete burial
of young plants as well as such important urban features as trails, tracks, railway lines,
roadways, pipelines, runways, landscaped areas and high valued land uses. There are
historical and contemporary examples of the abandonment of settled areas as a result of such
With its small grain size of 0.08 mm diameter, dust has lower specific gravity and higher
cohesiveness than sand, which has a grain size ranging from 0.08 to 2.0 mm diameter. Dust
travels suspended in wind often lifting to great heights and forming an aerodynamically
smooth cohesive surface, thereby allowing high velocity winds to entrain it. Sand, on the other
hand, travels in hops and jumps, and rebounds near the surface in what is known as “saltation
curtain”, often gaining flight momentum from air stream. Through shifting action during the
movement, sand is segregated from dust and are often built into superficial aeolian bedforms.
Thus the dynamic action of wind and fine surface materials is crucial to the shaping of the
desert landscape, and may be examined in terms of three related processes: deflation,
transport and deposition.
Deflation is the process whereby sand and dust are removed by wind action. It is induced by
human actions, which are initiated by preparation of land for urban and regional
Sand is transported by abrasive action at a ‘saltation height’ of one meter, while dust may rise
to several hundred meters rendering the sky hazy and dull. In the eastern regions of Saudi
Arabia, abrasion and transport is pronounced in summer under the impact of the high speed
northerly ‘shammal’ winds. Abrading sand and duststorms such as the Libyan ‘ghibli’ in Sahara
and the Saudi ‘belat’ in the Arabian Peninsula disintegrate soil, increase surface erodibility,
erode building materials, weaken utilities, damage mechanical equipments, and by reduced
visibility, disrupts urban and regional transportation. In the western Hejaz region of the
Kingdom also, the easterly ‘samoun’ wind is laden with sand and dust and causes like damage.
Sand and dust movement is a function of wind erosivity, which depends on the velocity,
frequency and intensity of wind, and of surface erodibility, which depends on the kind of
vegetation’s cover and type of surface soil.
At the depositional stage, dust and sand bury plants, increase road and runway skidding,
contaminate household stuffs, and create bouts of allergy and discomfort.
On transit or as sand dunes and ‘draa’, sands overwhelm urban infrastructures and cause
desertification, which depopulates settlements and increases migration.
In light of the preceding results and discussion, Riyadh city, Saudi Arabia, is subjected
to considerable dust storms almost all year. The fallout sediments are mainly represented by
two textural classes, loam and silt loam, of which silt is the dominant fraction. Quartz and
calcite were the dominant minerals in the dust samples. The dust contained high CaCO3,
averaging 31,8%. Appreciable amounts of heavy metals such as Pb, Zn, Cd, Ni and Co were
detected in the fallout sediments.
Maintenance of the railroad’s track
Railway safety experts from 13 countries on March 2003 concluded a three-day conference
on the hazardous effect of sand movement on railway tracks, recommending three measures
to counter the problem.
Safety experts said that most of the train accidents in the Arab and African countries were
caused by the accumulation of sand on the rail track and various methods adopted by these
countries had failed to provide any tangible result.
“It was therefore imperative for all of us to sit together and find a lasting and effective solution
to the crisis,” said Khaled Al-Yahya, president of the Saudi Railways Organization.
The conference in its final communiqué stressed on three possible means to contain sand
from reaching the tracks. Among the three measures, the experts first listed mechanical
means, which they said was found effective in several countries. They also suggested chemical
means to stop sand movement.
But the main thrust of the conference was on biological means, that is plantation of trees near
the railway track.
“This is a long term solution and will eventually prove more effective,” said an expert at the
Source : http://www.iorw.org/news_index.html
SRO, in conjunction with contractor Al-Moboty Co has ordered several SRM 500 sand removal
machines, which will be delivered by the end of this year, and a Unimat 08-32 4S two-sleeper
tamping machine, which will enter service in 2013. Plasser & Theurer is also supplying
contracting and track maintenance firm Saudi Archirodon an EM 120 track recording car,
which will measure, record and evaluate various track parameters.
Preventing and controlling aeolian sand
In his chapter on dune migration and encroachment, Goudie (2010a, p. 200-201) identifies
four main techniques, which are used in order to contain aeolian sand:
- 1. Endorse the deposition of drifting sand by devices such as ditches, barriers, and
fences, and vegetation belts.
- 2. Enhance the transportation of sand by aerodynamic streamlining and surface
- 3. Reduce the sand supply through surface treatments (e.g. water spraying,
chemical stabilizers, mulches), fences and vegetation strips.
- 4. Deflect the moving sand by using fences, barriers and tree belts.
When controlling mobile sand dunes, the main techniques are:
- 1. Sand dune removal by mechanical excavation and transportation to new location.
- 2. The dissipation of encroaching dunes by disrupting its aerodynamic profile by
reshaping, trenching, or surface treating.
- 3. Dune immobilization using surface strips, fences, etc.
According to Goudie (2010a), these diverse techniques are not very successful, and the best
adaptation would be to site and design engineering structures in order to allow the sand free
movement. In addition, one alternative is mapping different dune types in order to observe
their direction and mobility. Then it would be possible to arrange structures outside of risk-
areas. Goudie (2010a, p. 201)
notes that, “Avoidance may be better than defence”.
The effects of aeolian sand on infrastructures
According to the Stockholm University report, “Sand causes third derailment in weeks”
(Namib Times, 2009b), see figure below, the sand has caused a derailment of a freight train
on the railway line between Walvis Bay and Dune 7. Due to extreme windy conditions the sand
was able to accumulate rapidly, covering the entire track. The derailment cut Walvis Bay’s
railway link to Swakopmund and the rest of the country for one day. Furthermore, an article
from the 13th of October reports that Dune 7 has buried benches and other structures (Namib
Source : Bovin Mattias, Johnsson Caroline, tutor Christiansson Carl, Stockholm University, dept of Physical
Geography and Quarternary Geology, “The effects of Aeolian sand on Infrastructure in Walvis Bay”, report
Autumn term 2010 46 p.
Photos on the derailment (The Namib Times, 2009b)
!Goudie, Andrew, 2010a: Dune migration and encroachment. In, Geomorphological Hazards and Disaster
Prevention, eds. Irasema Alcántara-Ayala and Andrew S. Goudie. Published by Cambridge University Press.
Copyright Cambridge University Press 2010.
We note in this chapter on the aggressiveness of the sand action wear on buildings and
transport infrastructure such as railways to cause accidents by derailment.
Moreover, the abrasive action of sand on the rails and train wheels can lead to premature
wear of the rolling elements such as rails and wheels. If the maintenance of rolling stock and
the track does not follow, this can lead to derailment.
As well two actions are to be taken together, the removal of sand on the track from its
appearance after a storm and concerted implementation of the first long-term barriers to
either side of the railroad right of way to identify the sand locked when they are submerged
and plantations which would set the sand in the long term.
Lightning is an abrupt electric discharge from cloud to cloud or from cloud to earth
accompanied by the emission of light or it is a flash of light that accompanies an electric
discharge in the atmosphere, which can scintillate for a second or more.
It is helpful to construct a visual representation of lightning strike densities in countries such
as Saudi Arabia in order to locate areas, which are most likely to be stroked, and those, which
are not. By knowing where lightning strikes hit we can design better lightning insulation
systems for residential, commercial as well as industrial regions. Of most important is the
insulation required for power plants and transmission lines wither overhead or underground.
Consider the following approximated maps of lightning strokes in Saudi Arabia:
If we compare the following two figures, we note why it is important to have lightning
detection and mappings as illustrative methods in determining the rate of strokes and where
most likely they would hit.
Here, it is clear, that the Southern western region of Saudi Arabia is the most attacked by
lightning strikes thus resulting in possible faults in power lines in that area as shown in the
second figure which is a map showing transmission lines and their voltage rates.
Tamer Al-Alami, “Mapping lightning strikes in KSA: using numerical methods as a tool”, ppt
Flashes per square kilometre per month (from 0,1 to 50)
Detailed mapping with visible contours showing very lighting mostly strikes.
- SCECO-EAST: SCECO (Saudi Consolidated Electric Co.) Is the leading electric power company in Saudi Arabia
handling all generation, transmission and distribution activities and operations in the entire Kingdom.
- PDD: The Power Distribution Department mission is to manage the electrical power system of all Saudi
Aramco facilities under PDD area of responsibility in a safe, reliable and cost effective manner, exceeding
customer’s expectations. PDD was establi shed i n January 1983 as a maintenance department then evolving
into distribution of power to all facilities).
It therefore appears that there are numerous thunderstorms in Saudi Arabia followed by
lightning especially in areas with dark colors (flashes per square kilometer per month) shown
on the map that is west of the Saudi along the Red Sea, but also along the Persian Gulf and
especially in a line north west south east between Dammam and Riyadh.
Lightning protection systems to avoid lightning incident of signalling along the line after a
thunderstorm must protect electronic equipments along the way.
Earthquakes, and seismic risks
The Arabian tectonic plate is migrating away from the African Plate at a rate of around 2 cm
per year. In north - western and central western Arabia crustal extension is also occurring, and
has resulted in significant Cenozoic volcanism. The two most common types of volcanic
emission (more than 80 percent) in Saudi Arabia are shield volcanoes, with fairly flat slope,
due to thin fluid basalt lava flows.
Source: National Centre for Earthquakes and Volcanoes
A: The main Cenozoic lava fields (harrats) in western Saudi Arabia showing the MMN volcanic line.
B: The three-armed rift of the Red Sea – Gulf of Aden – East African Rift zone. The inferred mantle plume is
below the Afar triangle.
The more recent basaltic lava fields and volcanoes date from 10 million years ago up to the
historic eruptions. They lie along a 900 km line within the shield that extends south from the
Great Nafud Desert, through the cities of Al Madinah and Makkah, and then as far south along
the coastal plain as Al Qunfudah. The northernmost 600 km length of this trend takes the form
of a north-south graben structure about 600 km long through which the main Cenozoic
basaltic lava fields (harrats) have been erupted. This zone has been named the Makkah-
Madinah-Nafud (MMN) Volcanic line, and includes Harrats Rahat, Khaybar and Ithnayn. Harrat
Rahat, which extends between Makkah and Madinah, covers about 20,000 km2, and has 644
scoria cones, 36 shield volcanoes and 24 domes. The MMN volcanic line is a weakly
propagating rift zone where crustal extension has averaged about 0.054 mm per year over the
past 10 million years, and is distinct from the main Red Sea rift zone. It forms the axis of uplift
in western Saudi Arabia, and geothermal phenomena are observed along this trend.
Low level geothermal activity and seismicity indicate that the MMN trend remains active. The
areas of Cenozoic volcanism and the MMN volcanic line are shown in the map of the harrats.
Source : Shell Global Solutions International BV, « Dubai LNG Seismic Hazard Desk Study », Seismic Hazard Desk,
Study Rev A December 2006
Tectonics of the Arabian Plate
The crust of the earth is composed of many tectonic plates, and most of the major earthquakes
occur at the plate boundaries. The eastern and northern margins of the Arabian plate consist
of the Zagros and Makran Mountains in Iran, and the Taurus Mountains in southern Turkey,
and these form a convergent zone where the Arabian plate collides with the Eurasian plate.
The Arabian plate moves in a northeasterly direction between the Owen fracture zone and
the Dead Sea fault, with widening of the Red Sea and Gulf of Aden, and collision or subduction
with the Makran, Zagros, and Taurus Mountains.
Apart from the seismicity along the axis of the Red Sea and along the Gulf of Aden,
considerable activity occurs along the Dead Sea transform fault system, and many
earthquakes also occur due to collision at the subduction zone along the Zagros Mountain
belt. In the central and western part of the shield some of the Cenozoic volcanic areas are still
potentially active, and some seismicity is associated with this low-level volcanism.
As far as Saudi Arabia is concerned, the most active area is along the Gulf of Aqaba (Dead Sea
transform fault), where the left lateral movement relative to Sinai is 4 to 5 mm per year. The
region of the Gulf has active sinistral transform faults with associated pull-apart basins (the
deeps in the Gulf of Aqaba), and hence is an area where large damaging earthquakes occur
quite regularly. The last major event was the 1995 Haql earthquake in the Gulf of Aqaba
(magnitude 7.3), which caused significant damage on both sides of the Gulf and was felt
hundreds of kilometers away. Earthquakes of magnitude 6 are common along the spreading
axis of the Red Sea but generally they are not felt onshore and appear to pose little risk to
infrastructure. The figure here shows earthquake epicentres greater than magnitude 2 in the
SGS catalogue for all years up to 2009.
On 19 May, 2009, 19 earthquakes of M4.0 or greater took place in the volcanic area of Harrat
Lunayyir to the north of Yanbu, including a M5.4 event that caused minor damage to
structures in the town of Al Ays (40 km to the SE). This event produced the spectacular ground
cracks seen in the photograph below. The maximum actual dip-slip offset on the fault in the
hard rock in the nearby hills was about 90 cm.
Seismology at Saudia Geological Survey
Permanent stations from the other previous seismograph networks have now been integrated
with the SGS national network and upgraded using new broad -band instrumentation and
satellite telemetry. Most earthquakes greater than magnitude 2 within the Kingdom are now
routinely located and a comprehensive earthquake data- base has also been established for
earthquake research. The stations (about 75 at present, see map) are concentrated in western
Saudi Arabia, where most of the seismicity and hence the risk occurs. Eventually when the
network of about 100 stations is completed the coverage will enable earthquakes as small as
magnitude 2 to be detected and located anywhere within the Kingdom.
The SGS seismograph stations use a standard arrangement, with equipment manufactured by
Nanometrics Inc. in Canada. Each broad-band seismometer is on bedrock in an insulated
concrete vault about 2 m in depth, and is insulated to minimize temperature variations. Data
from remote sites are transmitted via satellite to the SGS processing centre in Jeddah and
satellite channel usage is managed via commands from the SGS seismic center.
Typical records of seismic waves arriving at 2 SGS stations from an earthquake in eastern
Saudi Arabia are shown. The first wave to arrive is the direct P (compressional) wave, followed
by a succession of P and S (shear waves). From the arrival times of these waves we can work
out the location of the earthquake.
The risk of damage from earthquakes is quite low over most of Saudi Arabia, the main areas
of risk being near the Gulf of Aqaba and Jizan, with lower risk in the west near the Red Sea
and in some of the harrats. The database is used to estimate the expected recurrence rate
for earthquakes of different magnitudes in areas of interest, from which statistical estimates
of risk are derived. The location can then be placed in the correct zone or level in the building
code so that appropriate methods of construction are used. This is particularly important for
large infrastructure projects. We undertake risk studies for other government departments
as well as for the private sector using our unique catalogue of earthquake activity.
Source: Jamal A. Abdalla and Azm Al-Homoud, American University of Sharjah, UAE, « Earthquake hazard zonation of
Eastern Arabia », paper n°1008 in 13th World Conference on Earthquake Engineering Vancouver, B.C. Canada, august 1-6
Tectonics of UAE and its vicinity
Seismic zoning map of UAE and its vicinity for 475 years return period showing five zones (0,1, 2A, 2B and 3)
KSA is a country of low seismic activity and scarce past earthquake data. The seismographic
installations in the country were commissioned in 1984. Contrary to common belief, there are
regions in the country where peak ground acceleration reaches 0,2g and 0,3 g in 50 years for
10 and 5 percent probabilities of excess respectively.
The region between Dammam and Riyadh is quite far from the iranian faults and the red sea
faults. A seismic zoning map of UAE and its vicinity for 475 years return period shows five
zones (0,1, 2A, 2B and 3) in the figure above: the Saudia Arabia region near east coast (Barhein)
is in a zone 0 to compare with others zone 1,2,2B & 3.
Rock Fall Hazards
Landslides are rock, earth, or debris flows on slopes due to gravity. They can occur on any
terrain given the right conditions of soil, moisture, and the angle of slope. Integral to the
natural process of the earth's surface geology, landslides serve to redistribute soil and
sediments in a process that can be in abrupt collapses or in slow gradual slides. Also known as
mud flows, debris flows, earth failures, and slope failures, they can be triggered by rain, floods,
earthquakes, and other natural causes as well as human-made causes, such as grading, terrain
cutting and filling, excessive development, and so on. The factors affecting landslides can be
geological or by man-made, and can occur in developed or undeveloped areas, or in areas
where the terrain has been altered for roads, houses, utilities, buildings and mining activities.
The Saudi Geological Survey is studying landslides in order to mitigate the risks. Landslides
may be more devastating than all other natural hazards combined, and can affect utilities,
transportation, and public and private infrastructure. Most of the rock slopes along the
descents between the Arabian Shield mountains and the Red Sea coast that cut through the
escarpment are subject to slope instability and rock falls, especially after rain storms.
Along the railway line 1 between Dammam and Riyadh we find some right of way in trench
with high chalk bluffs above the track: some chalk stones are put on the bluffs very near of
the edge, they could fall on the track before or during a train passing through. It is advised to
avoid chalk stones deposit near or above the railroad tracks.
Different types of sinkholes have been recognized in Saudi Arabia. The sinkholes are of various
sizes, shapes and occur at different depths. Their presence may cause a direct risk to
infrastructure such as urban areas, roads, areas being developed, and farmland. Some
sinkholes have also appeared in barren uninhabited areas. In recent years more than eight
large sinkholes or ground collapses have occurred to the west of Al Khafji and in the An
Nu’ayriyah area (northeast Saudi Arabia) due to dissolution of the underlying limestone.
It does not seem that there are sinkholes under the right of way of line 1 between Dammam
and Riyadh. Normally drill tests have been done before the opening of public works: if a
sinkhole stays under the tracks, after a rain storm the ballast will desappear slowly under the
sleepers and rails. Maintenance surveys have been done to watch that kind of problem.
Loess soil is an unconsolidated well-sorted deposit. It is relatively homogeneous, seemingly
non-stratified, and extremely porous. Loess has different definitions, but is generally
considered to be wind-blown (aeolian) silt where the sediments were transported by wind.
Loess soil mainly consists of quartz, feldspar and mica grains that are angular showing little
polishing or rounding. Because the grains are angular, loess often retains the shape of banks
for many years without slumping. The soil characteristic called vertical cleavage allows the
formation of cave dwellings. Loess may be readily eroded by water, wind and seismic activity.
Loess soil occurs in various areas in the Kingdom such as in Jizan city.
Along the railway line 1 between Dammam and Riyadh we find some right of way in trench
with high loess soil bluffs above the track: some loess soil or vertical cleavage are on the
bluffs very near of the edge, they could fall on the track before or during a train passing
through after rain storm.
Geology of the caves of Central Saudi Arabia
Caves are airfilled underground voids developed by the former action of water on rock that
over a long period of time was dissolved, opening up holes and tunnels in the ground. The
holes and tunnels in cave systems are normally interconnected, depending on how the water
seeped through the rock along joints and cracks, working its way down to the water table
below the surface of the ground.
The caves illustrated here are in limestone - the most common type of rock to have caves -
which in this part of Saudi Arabia consists of calcium carbonate and small amounts of
magnesium carbonate. The rocks found 50 million years ago from the calcareous shells and
skeletons of countless organisms that flourished in shallow warm seas that covered the
Arabian Peninsula. Over time, the shelly deposits were cemented by additional calcium
carbonate, became hard and turned into limestone, forming a geologic unit referred to as the
Umm el Radhuma and Rus Formations. Starting 25 million years ago, these formations were
raised above sea level by earth movements affecting the whole of the Middle East, and were
exposed to wind and rain at the surface.
The action of water percolating down through soluble rock is critical for the formation of most
caves. Some caves develop because sulphuric acid rises from deep below the surface, but this
is rare and it is not known if any of the caves in the Ma'aqala area formed in this fashion. Most
likely they all formed by water action - either by falling rain or by streams that sink into the
ground through joints and holes.
The process of forming caves in soluble rock is very slow. As rain falls through the air, it absorbs
a small amount of carbon dioxide and picks up additional carbon dioxide from the soil. The
result is a weak solution of carbonic acid that seeps downward, dissolving the limestone
bedrock and opening up cavities and inter-connected channels.
Ain Hit: Diving in the Desert
Southeast of Riyadh near AI Kharj lie several sinkholes that offer direct access to a vast aquifer
lying deep below the surface.
The most famous of these holes is Ain Hit where geologists, invited on a picnic by King
AbduIaziz, discovered the first surface outcrop of anhydrite in the Kingdom. In recent years
experienced cave divers have carried their heavy equipment into Ain Hit down to the edge of
a lake 120 meters below the surface. Using breathing equipment they began an exploration
of this Dahl's submerged passages, which, they claimed contained the clearest water they had
ever seen anywhere in the world.
Caves of the Summan Plateau
Saudi Arabia has hundreds of limestone caves located only a few hours north of Riyadh,
offering visitors a cool underground climate and stunning crystal formations.
Perhaps the most visited cave on the Summan Plateau is Dahl Murrubeh. This cave has a large
entrance 15 meters wide. A steep slope leads down to a large room softly lit by reflected
sunlight. In the summer, the cool and pleasant temperature of this room makes it a perfect
refuge from the intense heat on the surface, which can easily surpass 50° C (120° F).
The Jabal Al Qarah Caves, located approximately 13 km east of Al Hofuf, Eastern Province of
Saudi Arabia, are an intricate cave system developed in the calcareous sandstone, marl and
clay of the Upper Miocene to Lower Pliocene Hofuf Formation. Physiographically, the hill of
Jabal Al Qarah is an outlier mesa that is located at the eastern edge of the Shedgum Plateau,
the southern extension of the As Summan Plateau, and the larger Syrian Plateau to the north.
Based on cave morphology and interpreted evolutionary history, the Jabal Al Qarah caves
appear to be significantly different from other limestone caves reported in the As Summan
Plateau. Jabal Al Qarah is known for its tall, linear cave passages and narrow canyons. The
boxwork of linear passages are better developed here than any other known cave locations in
the Eastern Province. Petrographic data, especially an abundance of well-preserved
palygorskite type clay minerals, suggests that the Hofuf Formation was deposited in a mudflat-
dominated coastal plain environment.
2. Technological environment
General Environmental Protection Standards Applicable to Existing Facilities
1. All existing major facilities shall be operated and maintained so as to avoid excess of the
ambient environmental standards promulgated for the Kingdom. Additional control
technology shall be installed where necessary so as to avoid excess of the ambient
2. All existing facilities shall be operated and maintained so as to avoid the discharge of any
toxic substance, whether specifically regulated or not, in sufficient quantities to be harmful to
Pollution and SEVESO risks
Regarding the environment of the railway platform, we did not find an inventory of risks,
establishments such as refinery, stocks hydrocarbon, gas pipes or water pipes, which could
have a impact on a safe operation of trains in the event of an industrial accident or breakdown
or explosion. If these institutions exist along the railroad, there is a perimeter of protection
around these institutions: after one day trip from Dammam to Riyadh and return, it seems
that the cement factories, oil installations, are far enough of the tracks if some fire or
explosions happen in these factories.
Many power lines pass over the railway platform and could be a danger to trains if some steel
cable would break: in effect even if the voltage in the broken cable disappears immediately
after the break disjunction, perhaps the wire may cause damage to the train passing below
until to cause a derailment.
The level crossings
A level crossing operating
Crossings are protected by signaling for trains and road vehicles as well as two bumps to
force motorists to reduce speed of around 10 km / h and guards.
Freight trains that roll on a track parallel to that passenger trains can be hazardous in case of
leakage, explosion or derailment when passing passenger train.
The two plants encountered along the line between Dammam and Riyadh seem sufficiently
remote from railroads to present no danger if an explosion might occur in the ovens.
The oil plants
As for cement factories, oil installations seem sufficiently far from the railway line in case of
fire or explosion: for big fire nevertheless important measures should be taken against toxic
gases, passing trains stopping momentarily.
Earthworks site for the second railroad
The public works in progress for the second track should be conducted so as not to interfere
with the operation of trains passing over the current single track: surveyors, survey vehicles
and earthworks necessary for the second track should not be on the right of way of the track
Earthworks in progress to open the necessary space for the railroad
- Amjad Ali Rizvi, “Planning responses to Aeolian hazards in arid regions”, article in
Architecture and planning, vol.1 pp 59-74, J. King Saudi University Riyadh, dept. of Planning &
Urban studies, College of Architecture & Planning.
- Bovin Mattias, Johnsson Caroline, tutor Christiansson Carl, Stockholm University, dept of
Physical Geography and Quarternary Geology, “The effects of Aeolian sand on Infrastructure
in Walvis Bay”, report Autumn term 2010 46 p.
- Goudie, Andrew, 2010a: Dune migration and encroachment. In, Geomorphological Hazards
and Disaster Prevention, eds. Irasema Alcántara-Ayala and Andrew S. Goudie. Published by
Cambridge University Press. Copyright Cambridge University Press 2010.
- M. Al-Haddad, G.H. Siddiqi, R.Al-Zaid & A. Arafah, Dept Of civil Engineering King Saud
University, A. Necioglu & N. Turkelli Seismological Observatory, King Saud University,
« Seismic hazard and design criteria for Saudi Arabia », article in Earthquake Engineering,
Tenth World Conference, Balkema , Rotterdam ISBN 90 5410 060 5.
- Jabbar-Ali-Zakeri, Maryam Forghani, “Railway route design in Desert Areas”, article in
American Journal of Environmental Engineering, DOI: 10.5923/j.ajee.20120202.03, 2012 2 :
- Jamal A. Abdalla and Azm Al-Homoud, American University of Sharjah, UAE, « Earthquake
hazard zonation of Eastern Arabia », papern°1008 in 13th World Conference on Earthquake
Engineering Vancouver, B.C. Canada, august 1-6 2004.
- Jamal A. Abdall, and Azm Al-Homoud, « Earthquake hazard zonation of Eastern Arabia »,
American University of Sharjah, Sharjah, UAE, 13th World Conference on Earthquake
Engineering Vancouver, B.C., Canada, August 1-6, 2004, Paper No. 1008
- Mapping & Analysis of Lighting Strikes in Saudi Arabia with assistance of Numerical Methods,
- A.S. Modaihsh, Dept of Soil Science, College of Agriculture, King Saud University, Riyadh,
“Characteristics and composition of the falling dust sediments on Riyadh city, Saudi Arabia,
article in Journal of Arid Environments (1997) 36:211-223.
- Moutaz Al-Dabbas, Mohammed Ayad Abbas & Raad Al-Khafaji, University of Baghdad &
Ministry of Medecine, “The mineralogic and micro-organisms effects of regional dust storms
over middle east region, article in International Journal of water resources and arid
environments 1 (2): 129-141,2011 ISSN 2079-7079.
- Mahbub Hussain, Fadhel Al Khalifah , Earth Sciences Dpt KFA University of Petroleum &
Minerals Dahran, Nazrul Islam Khandaker, Dept of Natural Sciences, York College of Cuny
Jamaica , “The Jabal Al Qarah caves of the Hofuf area, northeastern Saudi Arabia: a geological
investigation, article in Journal of Cave and Karst Studies, v. 68 n°1, p12-21.
- Shell Global Solutions International BV, « Dubai LNG Seismic Hazard Desk Study », Seismic
Hazard Desk, Study Rev A December 2006.
- Tamer Al-Alami, « Mapping Lightning Strikes in KSA, using numerical methods as a tool »,
- Unified Facilities Criteria (UFC), “Railroad Track Maintenance & Safety Standards, Dept of
Defense, UFC 4-860-03, 13 February 2008, 107 p.
- Yassar A. Alamri, “Emergency management in Saudi Arabia: past, present and future”,
http://training.fema.gov/EMIWeb/edu/Comparative EM Book - EM...
- http://www.pme.gov.sa/en/env_prot.asp Environmental Protection standards: General
Environmental Law and rules for implementation, 15/10/2001