ministry of regional municipalities and water...
TRANSCRIPT
ByAhmed Said Al BarwaniWater Resources Expert
Ministry of Regional Municipalities and Water Resources
• Introduction• Oman Location and Climate• Characteristics of Arid Regions• Flash flooding in Oman• Flash Floods caused by Thunder storms • Flash Floods caused by Cyclones• Damages caused by Flash Floods• Government Initiatives in dealing with Floods• Other Water Resources Problems• Conclusions & Recommendations
Oman Location Located at the eastern corner of Arabian Peninsula. The land area of the Sultanate is 309,814km2, geographically,
75% of the total area is covered by desert, 15% mountainousarea and 5% are coastal areas and the rest is alluvial plains.
Climate Oman is an arid country;
the average annual rainfallis 100 mm, varying fromless than 20 mm in theinternal desert regions toover 350 mm in themountain areas.
The potential evaporationranging from 2000 to 3000mm. The temperaturevaries between 3°C inwinter (in the mountains)to 48°C in summer.
Characteristics of Arid Regions Rainfall is highly variable, in time and space. Floods are damaging and difficult to quantify. Data are limited –in extent, quality and record length. Absence of base flow. Sparsity of plant cover. High transmission losses. High potential evaporation and evapotranspiration. Groundwater recharge is extremely uncertain. Prevailing low infiltration rates of the rocky terrain
and high infiltration rates of the sandy/gravely alluvial beds in ephemeral watercourses .
Water Resources Renewed Water Resources are estimated at around 1300
million m3/year. The individual share of the renewed water is about 500
m3 annually. International indices regard this level as water poverty threshold.
A comprehensive development and constant increase in water demand.
Agriculture consumes more than 90% of the renewable water resources.
Water resources deficit is estimated at 378 m3/year. Occurrence of drought for more than five years is very
common.
RainfallFour Principal Mechanisms that cause Rainfall in Oman are:
Convective Rain Storms – Can develop any time of the year but mostly during the summer months.
Cold Frontal Troughs – Originating over Atlantic Ocean or Mediterranean Sea which are common during winter and early springs.
On Shore Monsoon Currents – Occur between June to September in a form of drizzle and effect the southern part (Dhofar).
Tropical Cyclone – moving in from Arabian Sea and results in very heavy rainfall in the Muscat, Sharqiyah and Dhofar coastal regions.
Flash Flooding in Oman In areas of steep topography and /or a small drainage
basins, floodwaters can rise very quickly in wadis with little or no warning. This condition is known as flash flooding.
A wadi is valley, gully, or streambed in that remains dry except during the rainy season.
Floods Tends to be an intense Short-term event, High velocities, Entire incident last only 4 -6 hours from start to finish.
Damage usually begins to occur within one hour after significant rainfall.
Rainfall in arid areas tend to be very localized, intense with short duration falling on bare land with limited or sparse vegetative cover generating flash floods.
Flash Floods Caused by Thunder Storms Thunder storms are common in
Oman and when associatedwith heavy rains they causeflash floods.
On the 14th April 2003 a line of thunderstorms.
Rainfall of 82 mm was recorded in Bahla within less than 12 hours.
Drowning of around 20 people Swept cars, uprooted trees,
destroyed roads, and damaged electricity and telephone cables
Continue… Dec. 1995 - 283 mm recorded in Musandam for the
month. It rained for 11 days, floods washed roads, hundreds of people had to leave their homes.
November 1997 –very heavy rainfall causing floods most part of the country. 83 mm of rainfall was recorded in one hour causing flash floods.
6-7 March, 1999 - Heavy rainfall causing flash floods especially in Sur. Gauging station recorded 1250 m3/sec.The village of Sur was covered with more than 1 meter flooding. Hundreds of people had to leave their houses.
History of TC That Affected Oman• June 1890 Tropical Cyclone (285mm) Muscat & Sohar• May 1963 Tropical Cyclone (269mm) Salalah• Nov 1966 Tropical Cyclone (202mm) Salalah• Dec 1971 Cyclonic storm (99mm) Masirah• Jun 1977 Tropical Cyclone (430mm) Masirah & (122mm) Salalah• Mar 1999 Low pressure-Sur• Oct 1999 Deep Low Pressure (69 mm) Salalah• May 2002 Cyclonic storm (58mm) Salalah• Sep 2004 Low Pressure (116 mm)• June, 2007 – Cyclone Gonu (626 mm) struck Muscat and eastern
parts of Oman.• June, 2010 – Cyclone Phet (603 mm) struck Muscat, eastern and
interior part of Oman.
Cyclone Gonu On the 5th June 2007 Tropical
Cyclone (Gonu) approached thecoast of Sharqiya Region nearRas AlHadd.
The most disastrous Tropicalcyclone ever recorded in thehistory of Oman TC record
T C Gonu was associated withHeavy Thunder storms, strongwinds, high sea and flooding
Surface wind reached toCategory 4 : 211-250 km/h.
49 people left died, andestimated loss of 1.5 billion R.O($4billion).
Cyclone Phet On the 4th June 2010 Tropical Cyclone
(Phet) approached the coast of Omannear Qalhat and proceeded to Muscatand Batinah region.
The second most disastrous Tropicalcyclone ever recorded in the history ofOman TC record
TC Phet was associated with HeavyThunder storms, strong winds, high seaand flooding. Surface wind reached toCategory 4 : 211-250 km/h at sea,however reduced to category 1 whenapproached the land.
6 people reported dead, and estimatedloss of R.O 780 million ($2billion).
Damages caused by Flash Floods• Damages caused as a result of flash flood are
enormous both on human lives and loss ofproperty.
• It is reported that flood disasters account for abouta third of all natural disasters by number andeconomic losses.
• Floods are responsible for over half of the deathsassociated with all such disasters.
• The following pictures are some of the examples offlood damages in Oman during different events
Flood Damages in Oman
Flood AdvantagesEven though the floods cause damages, they
also bring some advantages some of the advantages are:
Recharge the groundwater aquifers.Wash and clean the waste from wadi channels.Floods also act as sediment transport from
mountains to lower wadi catchments and the sea.
As an environmental gain reduces the sea bed erosion, controls saline intrusion and provides nutrients to the fish.
Flood Management and MitigationIt includes both Structural and Non-structural
measures:• Structural : dams, levees and dikes, reservoirs,
retarding basins, channel and catchment modification, drainage schemes and flood proofing of vulnerable properties and flood shelters.
• Non Structural: flood forecasting, flood warning and emergency planning, land use planning controls, acquisition and relocation, flood insurance , public information and education.
Government Initiatives in Dealing with Floods
Establishment of Hydro-meteorological network. Establishment of guidelines for development in flood prone
areas. Production of maps showing flood risk zones. Establishment of National Committee for Civil Defense
(NCCD) to deal with all kinds of disaster including floods. Construction of dams. Improvement of drainage systems especially in major cities. Possibility of introduction of flood warning systems. Establishment of Multi Hazard National Center.
Hydro-meteorological Network The Ministry operates
4640 different stations, 15of them working onsatellite & 30 GSMTelemetry stations with adatabase having records ofover 100 years in somerainfall stations.
While the meteorologicaldepartment operates morethan 30 weather stations.
Use of Hydrometric Data• Assessment and Management.• Landscape and Water Recourse Management.• Environmental Management• Power• Water supply• Transport• Flood Risk Management• Other
Guidelines for Development in Flood Prone Areas.
The developer or property owner must seek commentsand prior approval from MRMWR before a project in aflood risk zone is allowed to proceed for finaldetermination by the planning authority.
If a proposal for any major development in a medium orhigh risk flood zone will cause a significant reduction inchannel flow capacity, the developer or property owner isrequired to demonstrate to the planning authority andMRMWR that the proposal will not significantly increaseflood levels.
For projects in a high-risk flood zone, it is mandatory toincorporate foolproof evacuation measures.
Production of Flood Risk Maps The ministry prepared a series
of maps for flood-risk zones formajor cities.
The ministry is now in theprocess of updating these mapsand also plans are on the way tocover other areas which have notbeen covered by these maps.
These maps are used for townplanning and also valuable inhelping to determine the valueof insurance premiums onproperties against flooddamage.
H.E Inspector General Police Chairman
Asst. IGDY. Chairman
Their Excellencies Ministers &Undersecretaries
CoordinatorDirector Executive Office
Interior Health TransportCommunication
Social Development
Education Information Regional Municipal
Finance
Housing Electricity & Water
TradeIndustry
Oil Gas
SQU MuscatMunicipality
DhofarMunicipality
Armed Forces
DGCD
Establishment of National Committee for Civil Defense (NCCD)
NCCD Members
13
NCCD Strategic Goals
Establish effective network of local,
regional and international
contacts and relief agencies
Establish Effective National Disaster
Communication Structure
Ensure all major organisations have effective well-practised
Emergency Plans in place
Construction of Dams Construction of 14 flood protection dams, 32
groundwater recharge dams and more than 60 storagedams in various region and governorates of the Sultanate.
Since their implementation and until June 2010 the damsretained about 1235 million cubic meters of water. 57% ofthis quantity recharged the groundwater aquifers.
Implementation of the first phase of the biggest storagedam (also act as flood protection dam)in the Sultanate(Wadi Dayqah in Wilayat Quraiyat) and Commencing theWork of building the biggest dam for flood protection inWilayat Salalah.
Studying a number of options with regard to floodprotection dams in some of the regions exposed tofloods danger.
Recharge Dam
Storage Dam
Flood Protection Dam
Improvement of Drainage Systems The drainage system in many cities of the country are either
poor managed or not available. Actions have been taken to clean the available drainage and
open the wadi channels. The Muscat Municipality has just completed a master plan
on drainage for the greater Muscat area.
Flood Warning Systems The Ministry has
recognized the need forthe early flood warningsystems and consultedseveral organizations.
Installation of telemetrystations using GSM andsatellite communication.
Plans are on the way forinstallation of the earlyflood warning systems.
Other Water Resources ProblemsThe most noticeable water resources problems in
Oman are:
• Drought• Desertification• Salinity Intrusion• Pollution (mining activities, filling stations
leakage)• Over Abstraction of Groundwater• Wastewater Disposal
Because Oman lies at the arid and semi arid areas drought is common.
Lowering of water table on wells and aflaj discharge clearly shows the effect of over abstraction which lead to drought.
Reported Oman droughts period are:
DesertificationDesertification is defined as land degradation
in productivity or suitability for differentpurposes and occur in dry areas and semi-aridas a result of climatic factors and humanactivities of various overuse of the land, whichmight include: reuse of agriculture,earthmoving, cutting of trees and over grazing.
Desertification problems in Oman aremanifested in salinization, land degradationdue to overgrazing (especially in the Dhofarmountains areas), wind and water erosion andsand encroachment.
Salinity Intrusion Occur near costal areas due
to over pumping during the last three decades.
Studies (2005) showed that 13,000 hectare were degraded in the last 5 year from a total of 84,000 hectare.(15% of total Surveyed area).
Deterioration in water quality.
7% of the wells in the area were abandoned due to either salinization or dryness.
Wastewater Disposal Leaking septic tanks are major sources of groundwater
pollution in Oman. The presence of sewage works and the associated
sewage system present a risk of both bacteriological and chemical contamination of groundwater sources.
In Oman, wastewater piped collection system covered less than 50% of urbanized areas.
The government has increased its effort on waste water treatment and now all the gardens and road trees and grass in Muscat are irrigated using treated water.
Conclusion and Recommendations Floods are natural unavoidable events, therefore we all
should accept and develop the concept of “Living withFloods”.
The future vision of the country towards waterresources should focus on current water resourcesproblems and challenges.
The following action are recommended: Application of integrated flood management
including structural and non structural floodmeasures.
Continue…. Continue with the government efforts on flood
protection and flood risk measures. Further work is recommended on upgrading of the
existing monitoring network by automate the dataprocessing, provision of real-time data transmissionand network modeling.
Determine the wadi hydrology parameters in aridclimate including (topography, morphology, landcover, climate etc.) for representative wadis.
Increase the reuse of treated waste water. Reduce consumption by controlling water losses.
Continue…. Training and Public awareness ought to be strengthened in
the future to improve the way we deal with floods and useof water efficiently.
To reduce the impact of desertification the government hasalready taken action on controlled grazing and reduce thenumber of camels and cattle further action are needed tocontrol the abstraction of groundwater especially onagriculture use.
Encourage more scientific research to improve the currentknowledge base on water resources and coping with thewater resources problems.
Strengthen the international cooperation throughexchange of expertise and information.
