1 Ministry of Regional Municipalities and Water Resources By Ahmed Said Al Barwani Water Resources Expert
2 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
3 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% mountainous area and 5% are coastal areas and the rest is alluvial plains.
4 Climate Oman is an arid country; the average annual rainfall is 100 mm, varying from less than 20 mm in the internal desert regions to over 350 mm in the mountain areas. The potential evaporation ranging from 2000 to 3000 mm. The temperature varies between 3 C in winter (in the mountains) to 48 C in summer.
5 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.
6 Water Resources Renewed Water Resources are estimated at around 1300 million m 3 /year. The individual share of the renewed water is about 500 m 3 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 m 3 /year. Occurrence of drought for more than five years is very common.
7 Rainfall Four 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.
9 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.
12 Flash Floods Caused by Thunder Storms Thunder storms are common in Oman and when associated with heavy rains they cause flash floods. On the 14 th 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
13 Continue Dec 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, Heavy rainfall causing flash floods especially in Sur. Gauging station recorded 1250 m 3 /sec. The village of Sur was covered with more than 1 meter flooding. Hundreds of people had to leave their houses.
14 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.
15 Cyclone Gonu On the 5th June 2007 Tropical Cyclone (Gonu) approached the coast of Sharqiya Region near Ras AlHadd. The most disastrous Tropical cyclone ever recorded in the history of Oman TC record T C Gonu was associated with Heavy Thunder storms, strong winds, high sea and flooding Surface wind reached to Category 4 : km/h. 49 people left died, and estimated loss of 1.5 billion R.O ($4billion).
16 Cyclone Phet On the 4th June 2010 Tropical Cyclone (Phet) approached the coast of Oman near Qalhat and proceeded to Muscat and Batinah region. The second most disastrous Tropical cyclone ever recorded in the history of Oman TC record TC Phet was associated with Heavy Thunder storms, strong winds, high sea and flooding. Surface wind reached to Category 4 : km/h at sea, however reduced to category 1 when approached the land. 6 people reported dead, and estimated loss of R.O 780 million ($2billion).
17 Damages caused by Flash Floods Damages caused as a result of flash flood are enormous both on human lives and loss of property. It is reported that flood disasters account for about a third of all natural disasters by number and economic losses. Floods are responsible for over half of the deaths associated with all such disasters. The following pictures are some of the examples of flood damages in Oman during different events
18 Flood Damages in Oman
21 Flood Advantages Even 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.
22 Flood Management and Mitigation It 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.
23 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.
24 Hydro-meteorological Network The Ministry operates 4640 different stations, 15 of them working on satellite & 30 GSM Telemetry stations with a database having records of over 100 years in some rainfall stations. While the meteorological department operates more than 30 weather stations.
25 Use of Hydrometric Data Assessment and Management. Landscape and Water Recourse Management. Environmental Management Power Water supply Transport Flood Risk Management Other
26 Guidelines for Development in Flood Prone Areas. The developer or property owner must seek comments and prior approval from MRMWR before a project in a flood risk zone is allowed to proceed for final determination by the planning authority. If a proposal for any major development in a medium or high risk flood zone will cause a significant reduction in channel flow capacity, the developeror property owner is required to demonstrate to the planning authority and MRMWR that the proposal will not significantly increase flood levels. For projects in a high-risk flood zone, it is mandatory to incorporate foolproof evacuation measures.
27 Production of Flood Risk Maps The ministry prepared a series of maps for flood-risk zones for major cities. The ministry is now in the process of updating these maps and also plans are on the way to cover other areas which have not been covered by these maps. These maps are used for town planning and also valuable in helping to determine the value of insurance premiums on properties against flood damage.
28 Establishment of National Committee for Civil Defense (NCCD) NCCD Members H.E Inspector General Police Chairman Asst. IG DY. Chairman Coordinator Director Executive Office Their Excellencies Ministers & Undersecretaries Finance Information Education Social Development Regional Municipal Transport Communication Health Interior DGCD Armed Forces Dhofar Municipality Muscat Municipality SQU Oil Gas Trade Industry Housing Electricity & Water
29 13 NCCD Strategic Goals Ensure all major organisations have effective well-practised Emergency Plans in place Establish Effective National Disaster Communication Structure Establish effective network of local, regional and international contacts and relief agencies
30 Construction of Dams Construction of 14 flood protection dams, 32 groundwater recharge dams and more than 60 storage dams in various region and governorates of the Sultanate. Since their implementation and until June 2010 the dams retained about 1235 million cubic meters of water. 57% of this quantity recharged the groundwateraquifers. Implementation of the first phase of the biggest storage dam (also act as flood protection dam)in the Sultanate (Wadi Dayqah in Wilayat Quraiyat) and Commencing the Work of building the biggest dam for flood protection in Wilayat Salalah. Studying a number of options with regard to flood protection dams in some of the regions exposed to floods danger.
31 Recharge Dam
32 Storage Dam
33 Flood Protection Dam
34 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.
35 Flood Warning Systems The Ministry has recognized the need for the early flood warning systems and consulted several organizations. Installation of telemetry stations using GSM and satellite communication. Plans are on the way for installation of the early flood warningsystems.
36 Other Water Resources Problems The most noticeable water resources problems in Oman are: Drought Desertification Salinity Intrusion Pollution (mining activities, filling stations leakage) Over Abstraction of Groundwater Wastewater Disposal
37 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:
39 Desertification Desertification is defined as land degradation in productivity or suitability for different purposes and occur in dry areas and semi-arid as a result of climatic factors and human activities of various overuse of the land, which might include: reuse of agriculture, earthmoving, cutting of trees and over grazing. Desertification problems in Oman are manifested in salinization, land degradation due to overgrazing (especially in the Dhofar mountains areas), wind and water erosion and sand encroachment.
40 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.
41 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.
42 Conclusion and Recommendations Floods are natural unavoidable events, therefore we all should accept and develop the concept of Living with Floods. The future vision of the country towards water resources should focus on current water resources problems and challenges. The following action are recommended: Application of integrated flood management including structural and non structural flood measures.
43 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 data processing, provision of real-time data transmission and network modeling. Determine the wadi hydrology parameters in arid climate including (topography, morphology, land cover, climate etc.) for representative wadis. Increase the reuse of treated waste water. Reduce consumption by controlling water losses.
44 Continue. Training and Public awareness ought to be strengthened in the future to improve the way we deal with floods and use of water efficiently. To reduce the impact of desertification the government has already taken action on controlled grazing and reduce the number of camels and cattle further action are needed to control the abstraction of groundwater especially on agriculture use. Encourage more scientific research to improve the current knowledge base on water resources and coping with the water resources problems. Strengthen the international cooperation through exchange of expertise and information.
45 Thank You Website: mrmwr.gov.om