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|Regional report:||Water Report 34, 2009: English or Arabic|
Yemen, with a total area of 527 970 km2, is located on the south-western edge of the Arabian Peninsula. Apart from the mainland it includes many islands, the largest of which are Socotra in the Arabian Sea and Kamaran in the Red Sea. The country is bordered by Saudi Arabia to the north, Oman to the east, the Arabian Sea and the Gulf of Aden to the south, and the Red Sea to the west. The present Republic of Yemen was created in 1990 as a result of the unification of the former Yemen Arab Republic (YAR) and the People’s Democratic Republic of Yemen (PDRY). The country is divided into 21 administrative governorates, including the three newly created governorates Amran and Al-Daleh, created in 2000, and Raimah, created in 2004.
The cultivable land is estimated at about 3.62 million ha, which is 7 percent of the total area. In 2004 the total cultivated area was 1.19 million ha, compared with 1.05 million ha in 1994, of which 81 percent consisted of temporary crops and 19 percent of permanent crops (Table 1). The main crops were cereals, covering about 686 000 ha (58 percent of the total cultivated area), and qat, covering 122 844 ha (10 percent). Farm size, including both rainfed and irrigated agriculture, is generally very small: 62 percent of farms have less than 2 ha, while only 4 percent cover more than 10 ha.
Geographically, the country can be divided into three physiographic regions: the western, the eastern and the southern escarpment. Cultivated areas are mostly silty, with a high degree of heterogeneity, both laterally and vertically. Lower wadi reaches are extensively affected by blown sand, which tends to form dunes. The wadi soils are alluvial deposits, mostly consisting of fine sands and silts, which may reach several metres in depth. Agricultural soils have a high pH of about 7.8 to 8.0, very little organic matter and are nearly always deficient in nitrogen and phosphorus. Most of the land areas in the highlands are steep, rugged and badly eroded as a consequence of overgrazing and removal of woody vegetation. Agriculture is restricted to hillside terraces and riparian farms on the sides of the wadis, which range in size from a few metres to more than 100 metres, depending on the geologic and geomorphic features of the wadis. Soils captured by terraces show profiles of varying depths and morphology.
The climate is semi-arid to arid. Rainy seasons occur during the spring and the summer. Rainfall depends on two main mechanisms: the Red Sea Convergence Zone (RSCZ) and the monsoonal Inter-Tropical Convergence Zone (ITCZ). The RSCZ is active from March to May. Its influence is most noticeable at the higher altitudes in the western parts of the country. The ITCZ reaches Yemen in July-September, moving north and then south again so that its influence lasts longer in the south. Rainstorms observed during the winter months of December and January are attributed to the influence of the Mediterranean Sea.
The country can be divided into fourteen agro-climatic zones, which can be grouped into five regions:
Total population is almost 21 million (2005), of which 74 percent is rural (Table 1). The average annual demographic growth rate is estimated at 3.2 percent during the period 2000-2005. The average population density is about 40 inhabitants/km2, but the population density is quite different from one governorate to another. About 43 percent of the population lives in four governorates: Ta’iiz with 2.4 million, Hodiedah with 2.2 million, Ibb with 2.1 million and the capital city Sana’a with 1.8 million inhabitants. This is closely related to the physical environment. By far the largest part of the population lives in the Yemen Mountain area in the western part of the country, where rainfall is still significant, although not high in many locations. The hostile environment of the desert and eastern upland areas is reflected in low population density.
In 2006, 46 percent of the population had access to improved sanitation (88 and 30 percent in urban and rural areas respectively) and 66 percent had access to improved water sources (68 and 65 percent in urban and rural areas respectively).
In 2007, the national Gross Domestic Product (GDP) of Yemen was US$22.5 billion. The total economically active population was 6.8 million (32.5 percent of the total population), of which 71.5 percent male and 28.5 percent female.
The agriculture sector plays an important role in the economy of the country. Although its contribution to GDP is only about 10 percent (2000), the sector employs more than 45 percent of the total economically active population (50.4 percent in 2000) and provides livelihood to more than two-thirds of the population. The discrepancy between the contribution of agriculture to GDP and the percentage of those employed in this sector reflects seasonal employment, underemployment and the low productivity of workers and factors of production, thus resulting in low incomes and poor standards of living for workers in agriculture. Women are involved in nearly all agricultural activities, providing 44 percent of the population economically active in this sector, but cultural traditions keep them at a lower status and prevent them from gaining control over important household resources.
According to the Agriculture Census, the total cereal area showed a negative trend between 1998 and 2004, with total cereal production decreasing by 0.6 percent per year. The average domestic cereal production in 2000–2004 covered only 21 percent of the domestic demand, estimated at 2.73 million tons. The cost of imported cereal has increased from US$195.2 million in 2000 to US$315 million in 2004. When aggregating main food imports, cereals (2.3 million tons), sugar (468 000 tons), vegetables and fruit (77 000 tons), livestock and milk products (164 000 tons), the food import bill reaches US$744 million. Food exports total around US$236 million and are dominated by fish products with 76 percent of food export value (US$181 million), coffee (US$14.4 million), banana (US$8 million), onion (US$7.6 million) and other fruits (US$4.3 million).
Annual rain volume all over the country varies between 67 and 93 km3. Precipitation falls more on the western highlands, southwest highlands and the upper plateaus. It then gradually becomes lower towards the east. The ratio between the rainfall and potential evaporation reaches around 0.03–0.25 in the Rub Al Khali Desert.
The country can be subdivided into four major drainage basins, grouping numerous smaller wadis:
The floods of the wadis are generally characterized by abruptly rising peaks that rapidly recede. Between the irregular floods the wadis are either dry or carry only minor base flows. Surface water resources have been estimated at 2 km3/year, but this quantity corresponds to the runoff from major rivers and does not include the runoff produced within the smaller catchments. Renewable groundwater resources have been estimated at l.5 km3/year of which a large part, estimated at 1.4 km3/year, probably comes from infiltration in the river beds. Total internal renewable water resources are thus estimated at around 2.1 km3/year (Table 2).
Surface runoff to the sea measured in some major wadis is estimated at 270 million m3/year and groundwater outflow to the sea at 280 million m3/year. There might be some groundwater flowing into Saudi Arabia but no data are available. The existence of surface drainage crossing into Saudi Arabia suggests that some sharing of surface flows could be possible, but details are not known.
The volume of groundwater reaches around 10 km3, of which 1 km3 in the Al-Masila Basin, 2.5 km3 in the Tihama Basin and the remaining distributed over the other regions.
Yemen has a long history of dam construction and the ancient civilization was founded upon the great dam of Ma’areb, the destruction of which marked the end of its existence. After the revolution, the government carried out the reconstruction of the Ma’areb Dam financed by the United Arab Emirates. The new dam has a capacity of 400 million m3. The remaining dams have a total capacity of 62.5 million m3, giving a total dam capacity of 462.5 million m3.
There are over a thousand hydraulic structures falling into three different categories:
Thirteen wastewater treatment plants (WWTP) are in operation. They are concentrated in the capitals of the governorates and in some secondary cities. However, while the cities are growing fast, the capacity of the plants has not increased. For example, in Sana’a the WWTP was designed to treat 25 000 m3/day of wastewater, but now it receives more than 50 000 m3/day. Similarly, in Ibb city the WWTP was designed to receive 5 000 m3/day, but now it receives more than 10 000 m3/day. These examples reflect the insufficient treatment leading to the production of bad quality water that is not suitable for irrigation. The Ministry of Agriculture and Irrigation considers this water to be harmful and it should be appropriately treated in a way that prevents environmental pollution. In 2000, the total volume of produced wastewater was 74 million m3 and the treated wastewater was 46 million m3 in 1999, while the amount of treated wastewater used in agriculture was only 6 million m3/year in 2000.
In 2002, the total installed gross desalination capacity (design capacity) was 76 596 m3/day or 28 million m3/year (Wangnick Consulting, 2002). The production of desalinated water reached 25.1 million m3 in 2006, an increase of 151 percent compared with 1989, contributing to the water supply of Aden city.
Between 1990 and 2000 total water withdrawal increased from 2.9 km3/year to 3.4 km3/year. In 2000, 90 percent of water withdrawal was used for agricultural purposes, 8 percent for municipal use and 2 percent for industrial use (Table 3 and Figure 1). Most of the water withdrawn was groundwater (from wells and springs) (Figure 2), resulting in groundwater depletion as withdrawal exceeded the annual groundwater recharge. The rate of decline of the groundwater levels is alarmingly high in many zones, especially in the highlands, where a decline of 2 to 6 m/year is commonly observed. In coastal zones overexploitation of groundwater leads to salt water intrusion. The decline in groundwater tables has also significantly reduced spring-fed irrigation.
Many farmers are pumping groundwater from wells using diesel or electric pumps. The yield of wells is between 5 and 50 l/sec. It is estimated that there are 52 000 to 55 000 active wells in Yemen. The volume of the water that is pumped every year from these wells is about 1.5 km3. About 800 water well drilling rigs are in use that are owned by individuals or companies which generally do not have any permits despite government legislation limiting the drilling of wells. Recently, the National Water Resources Authority started a programme of registrations & licensing for the water well drilling companies; the records show that in May 2005 only 70 rigs were licensed and only 1 000 wells were registered and licensed (Al-Asbahi, 2005).
Two types of treated wastewater reuse in agriculture exist (Al-Asbahi, 2001):
An undefined quantity of brackish water is used in the rock cutting industry, mainly in the highlands, as well as for irrigating some salt-tolerant crops, mainly in the coastal plains (Al-Asbahi, 2005).
A global figure for irrigation potential is not available. In 2004, the total water management area was estimated at 679 650 ha, an increase of around 41 percent compared with 1994 (Table 4). Three main types of water management exist:
Irrigation efficiency is low, between 35 and 45 percent depending on field levelling and the water conveyance system used. Localized irrigation systems (drip and bubbler) are introduced through several projects on limited demonstration areas and 485 ha have been realized up to now. Because of the high cost of sprinkler irrigation systems, they have been installed in very limited areas only, such as the governmental farms and the big investment farms mostly used for fodder crop production. To enhance water conveyance and distribution efficiency, the government introduced PVC buried pipes and GI pipes to the farmers to replace the earthen distribution canals and offered subsidies reaching 50 percent of the equipment costs. It is estimated that irrigation efficiency could be increased to 60 percent by installing the conveyance pipe system and to over 80 percent by adopting localized irrigation systems. Average yields of crops growing under the improved conveyance pipe system and localized irrigation systems are assumed to increase by 5 percent and 10 percent respectively. In 2004, 99.9 percent was surface irrigation and 0.1 percent was localized irrigation (Figure 3).
The price of irrigation equipment has increased considerably in recent years. The average cost of a surface irrigation system with a piped conveyance and distribution system is about US$800/ha. The cost of a localized irrigation system depends on the type: the estimated cost of a drip irrigation system for fruit trees is about US$2 600/ha and for vegetables about US$3 600/ha, while a bubbler irrigation system costs about US$3 000/ha. A central pivot sprinkler system is estimated to cost about US$6 000–8 000/ha. The cost of the operation and maintenance is approximately US$120/ha for the piped surface irrigation system and US$300/ha for a localized irrigation system. The farmers are responsible for operation and maintenance costs.
Government action focuses on the construction of water harvesting schemes and spate irrigation structures with the participation of the beneficiaries, as well as on the rehabilitation of those structures. The beneficiaries are responsible for operation and maintenance. The cost of small and medium spate diversion works and water harvesting structures is between US$1 500 and 2 000/ha.
The crops grown under full/partial control irrigation can be aggregated into six types: cereals, fruits, vegetables, cash crops, pulses and fodders. In 2004, the total harvested irrigated cropped area was 527 038 ha distributed as follows (Figure 4):
The Ministry of Agriculture and Irrigation (MAI) is responsible for formulating policies on irrigation, crops, livestock and forestry production and for coordinating public investment and services in the agricultural sector. The General Directorate of Irrigation (GDI) is located within the Ministry and carries out all the duties related to irrigation, particularly the construction of dams and water harvesting and spate structures. Most field services are provided to farmers through decentralized Regional Agriculture and Irrigation Offices (RAIO) in the different governorates of the country. Several projects are working under the supervision of the MAI to provide different services, particularly the introduction of water saving techniques and the construction of water harvesting and spate structures. Other areas of action include wadi bank protection and the rehabilitation of abused terraces, as well as the rehabilitation and maintenance of existing irrigation structures. To support agricultural development at the regional level, three Regional Development Authorities (RDA) have been established in the northern governorates: (i) Tihama Development Authority (TDA), (ii) Sana’a, Sa’dah, Hajjah and Amran Rural Development Authority (SSHARDA) and (iii) Eastern Region Agricultural Development Authority (ERADA). Although RDAs have not been established in the southern governorates, agricultural production in wadis such as Wadi Hadramout, Wadi Tuban, Wadi Beihan has been supported by donor agencies through the Directorates of Agriculture in the respective governorates. In addition to the above authorities, the Agriculture Research and Extension Authority (AREA) is working under the umbrella of the Ministry. The Agricultural Cooperative Union (ACU) was established in August 1991 with 213 societies. Its main objective is to consolidate integration and coordination with the government effort in setting up several common projects, of which the most important ones are infrastructure projects such as water storage, regulation dams and weirs, and agricultural marketing. It also supplies agricultural inputs and means for livestock development. At present the ACU has four general societies with 400 primary societies and 20 branches in all the provinces of the country.
The Ministry of Water and Environment (MWE) was established in May 2003. It is responsible for water resource planning and monitoring, legislation and public awareness. MWE has many sub-sectors and authorities such as the National Water Resources Authority (NWRA), Environment Protection Authority (EPA), General Rural Water Authority (GRWA), Urban Water Supply and Sanitation Corporation, and Rural Water Supply and Sanitation Corporation.
The Ministry of Public Works and Urban Planning (MPWUP) is responsible for observing and monitoring the drinking water purification stations. The Ministry of Local Administration (MLA) is responsible for water supply and sanitation in rural areas.
According to the Constitution, surface water and groundwater resources are defined as ‘res communis’. However, a landowner has ‘precedence’ for water taken from a well on his land. In spring-irrigated areas water can be attached to land in the form of ‘turns’, which give rights to divert the canal into the field for a fixed period of time. The ‘turn’ can, however, be detached from the land and sold or rented separately. This landowner’s ‘precedence’ has permitted the private development of deep tubewell extraction, which is in some ways in conflict with Islamic principles. Islamic and customary law has no precedent for dealing with a new technology that allows landowners to extract (and sell) unlimited quantities of water from deep aquifers, and modern law has not yet regulated it either.
Following the Water Law, water user associations (WUAs), water user groups (WUGs) and water councils (WCs) were established to transfer operation and maintenance (O&M) functions of the spate irrigation and groundwater irrigation schemes from the MAI to the user organizations. Up to now, 65 WUAs, 1 287 WUGs and 2 WCs (in Wadi Zabid and Wadi Tuban) have been established. They have received training on issues such as technical, financial and administrative management, provided by different projects.
Between 2005 and 2006 the International Programme for Technology and Research in Irrigation and Drainage (IPTRID), carried out the Project Design and Management Training Programme (PDM) for Professionals in the Water Sector in some countries of the Near East such as Yemen. The objective of the programme is to strengthen participants’ capacities in developing more effective and efficient projects to address pressing water issues in the region (FAO, 2008).
The government recognizes the critical water situation in the country and is undertaking different actions to deal with it. Several water sector strategies, legislations and policies have been prepared and implementation of some of them has begun. The Water Law was enacted on 31 August 2002, and amended by Parliament in December 2006. Implementation of this law will give a major thrust to the issue of water conservation. On 19 November 2002, the Cabinet passed a decree proclaiming Sa’dah, Sana’a and Ta’iiz protected areas, as stipulated in Article 49 of the Water Law. The National Water Resources Authority (NWRA) will monitor closely these critical areas.
The following policies and the strategies have been developed after assessment of the water sector and irrigation sub-sector:
The successful and sustainable exploitation of water resources is threatened by the rapid depletion of groundwater resources. Almost all the important groundwater systems are being over-exploited at an alarming rate. The socioeconomic consequences of groundwater depletion are dramatic because it will become too expensive for use in agriculture and, as a result, regional agricultural economies based on groundwater irrigation are doomed to collapse if the water resources are not adequately controlled. Groundwater availability may be further reduced by groundwater salinization in coastal areas and groundwater pollution in urban areas and areas of intensive agriculture. A study conducted by the Tehama Development Authority (2004) reported that the EC increased from 225 to 3 480 µs/cm (at 25 °C) in the Al-Jar area as a result of sea water intrusion. The Al-Jar region is located in the northwest of the Yemeni coastal area, 8 km away from the Red Sea. During the last ten years there has been a huge investment in this area, leading to the cultivation of more than 3 500 ha of mango trees and the drilling of about 2 000 wells. In the whole country, the area cultivated with high water consuming crops increased, such as the area under qat, which has more than tripled in 25 years.
The quality of treated wastewater varies from one area to another. While the quality is very good in Hajah, it is very bad in Ta’iiz, depending on the method of treatment as well as the capacity of the station and the operational circumstances. The quality affects the farmers’ willingness to use such water for their crops (Al-Asbahi, 2005). Moreover, the outflow of the WWTP stations in the coastal areas becomes a source of groundwater pollution.
Environmental degradation occurs in areas where springs have dried up or where treatment plants are not able to treat oil residues and discharge the raw wastewater directly to the wadis (such as from the Sana’a station). Water scarcity leads to ever-increasing competition which, if uncontrolled, might lead to socioeconomic problems.
Reducing the gap between water abstraction and available renewable resources and improving the efficiency of water management is a priority. Specific objectives of the second Five-Year Plan are: optimal exploitation of available water resources; improving the means and techniques for water resources recovery and for feeding aquifers; and protecting water resources from pollution.
To achieve these objectives, the government plans to make investments in groundwater recharge, water harvesting, encouragement of traditional and modern water management techniques, and application of modern irrigation techniques. Furthermore, it plans to invest in improving water use efficiency, capacity building, public and social awareness, as well as to pursue policies for equitable distribution of available water resources in rural and urban areas.
Strategies dealing more specifically with the various challenges of irrigated agriculture are set out in the National Water Strategy, adopted by the Council of Ministers in 1999, and in the National Irrigation Strategy, adopted by the Council of Ministers in 2001, which highlight the following aspects:
Concerning O&M of large spate works, decrees have already been issued for Lahej and Abyan governorates to charge an irrigation fee from the farmers on the basis of areas actually irrigated; this will be used for O&M of the head works and the main canals to be implemented by the Government. Farmers themselves are responsible for O&M of the tertiary canals.
Agriculture Research and Extension Authority (AREA). 2005. Maps of agriculture and environment resources in Republic of Yemen. Ministry of Agriculture and Irrigation (MAI).
Al-Asbahi, Q.Y.A.M. 2001. Yemen: Water resources and treated wastewater.
Al-Asbahi, Q.Y.A.M. 2005. Water resources information in Yemen. IWG-Env, International Work Session on Water Statistics, Vienna, June 20-22, 2005.
Al-Kurasani, M.A. 2005. Guide of agricultural weather in Yemen. Ministry of Agriculture and Irrigation (MAI), Agriculture Research and Extension Authority (AREA).
Ateyah, H.H. 2001. Study on the reuse of the treated wastewater in the agriculture.
Consulting Engineering Services Private Ltd. 1991. Land and water resources and irrigation development study. New Delhi, India.
FAO. 2008. Project Design & Management Training Programme for Professionals in the Water Sector in the Middle East.
General Department of Agricultural Statistics (GDAS). 2004. Agricultural Statistics Yearbook 2004. Ministry of Agriculture and Irrigation (MAI).
General Department of Irrigation (GDI). 2004. Steps on the way part (1): Dams and water structures. Ministry of Agriculture and Irrigation (MAI).
General Department of Irrigation (GDI). 2005. Steps on the way part (2): Dams and water structures. Ministry of Agriculture and Irrigation (MAI).
Groundwater and Soil Conservation Project (GSCP). 2003. Preparation study report for the project. Ministry of Agriculture and Irrigation (MAI).
Ministry of Oil and Mineral Resources & TNO Institute of Applied Geoscience (Netherlands). 1995. The water resources of Yemen: a summary and digest of available information. Report compiled by Van der Gun, J.A.M. and Abdul Aziz Ahmed.
Ministry of Planning and International Cooperation (MOPIC) and Ministry of Agriculture and Irrigation (MAI). 2002. National Conference on Qat (Technical Study). In cooperation with FAO and other donors.
Ministry of Water and Environment (MWE). 2005. National water strategy and implementation plan (NWSSIP).
TS/HWC-UNDP/DESD. 1995. Final reports. Volume III: Surface water resources; Volume IV: Groundwater resources; Volume VI: Water supply, wastewater and sanitation.
Wangnick Consulting. 2002. IDA Worldwide desalting plants inventory. Report No. 17. Sponsored by the International Desalination Association (IDA).
World Bank. 1993. Republic of Yemen, Agricultural sector study: Strategy for sustainable agricultural production. Report No 11126-YEM.
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