Zimbabwe
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Geography, climate and populationZimbabwe is a landlocked country, located in southern Africa between a latitude of about 15 and 22° south and a longitude of between 26 and 34° east, with a total area of 390 760 km2. The country is bordered by Zambia in the north, Mozambique in the east, South Africa in the south, and Botswana and Namibia in the west. Four major relief regions are generally recognized on the basis of their elevation: i) the lowveldt (< 600 m above mean sea level); ii) the middleveldt (600-1 200 m); iii) the highveldt (1 200-2 000 m); iv) the Eastern Highlands (2 000-2 400 m). Zimbabwean soils are derived predominantly from granite and are often sandy, light textured and of fair agricultural potential. However soils with significant clay content and of excellent agricultural potential are also found in all regions of the country. The cultivated area was estimated at 3.35 million ha in 2002, of which 3.22 million ha arable land and 0.13 million ha permanent crops (Table 1). Climatic conditions in Zimbabwe are largely subtropical with one rainy season, from April to August, a cool winter season from April to August and the hottest and driest period from September to mid-November. Average annual rainfall is 657 mm, but ranges from over 1 000 mm in the Eastern Highlands to around 300-450 mm in the lowveldt in the south. Rainfall reliability in the country decreases from north to south and also from east to west. Evaporation varies over the country to a much smaller extent than rainfall. Values of net annual pan evaporation range from about 1 400 mm in the Eastern Highlands up to 2 200 mm in the lowveldt. Only 37 percent of the country receives adequate rainfall for agriculture. For the rest of the country the rainfall pattern is insufficient, erratic and unreliable making supplementary or full-time irrigation indispensable for successful agriculture. Total population is estimated at about 12.9 million of which 64 percent is rural (2004). The estimated annual growth rate is about 1.02 percent. In 2002, population access to improved drinking water sources was said to be 100 percent in urban areas and 74 percent in rural areas (Table 1). Currently the economy is not performing well and from 1997 to 2002 the GDP has declined by more than 15 percent. Inflation was estimated to be about 160 percent and direct foreign investment had all but evaporated. Unemployment levels were above 50 percent. Economy, agriculture and food securityAgriculture is the cornerstone of the Zimbabwean economy and about 60 percent of the economically active population depends on it for food and employment. Women play an important role in agriculture and it is estimated that 70 percent of small-scale farmers are women. The agricultural sector accounts for about 17 percent of the country’s Gross Domestic Product (GDP), 60 percent of the raw materials required by the manufacturing industry and 40 percent of total export earnings. The country is divided into five Natural Regions (NRs) which relate climate, soils and topography to appropriate farming systems. The highest agricultural potential is found in NR I in the Eastern Highlands and the potential declines when moving from NR I to NR V, the latter being located in the southern part of the country and in the northwest. The major constraint to agricultural production in the country is drought. Whereas in years of good rainfall the country produces enough to feed the nation and enjoys a surplus for export, in years of drought the reverse is the case. About 80 percent of the land area lies in NRs III, IV and V where rainfall is erratic and inadequate, making rainfed agriculture a risky venture. In these areas irrigation is a prerequisite for successful crop production. Water resources and useWater resources Total internal renewable water resources have been estimated at 12.26 km3/year, of which 11.26 km3 are surface water resources, 6.00 km3 are groundwater resources. The overlap between surface water and groundwater resources has been estimated to be 5.00 km3 (Table 2). Zimbabwe is bordered to the north by the Zambezi River and to the south by the Limpopo River, both of which flow into Mozambique. The country consists of the following major river systems which form the basis of the seven river catchments the country has been divided into: Save, Runde, Mzingwane, Gwayi, Sanyati, Manyame and Mazowe. With the exception of the Save and Runde the other main rivers drain into either the Zambezi or Limpopo. The annual potential yield at 10 percent risk (resources in a dry year of a 10th year frequency) from all river basins in the country has been estimated to be 11.26 km3/year. This assessment excludes external surface water resources from such bordering international rivers like the Zambezi and Limpopo. Out of this potential yield and allowing for topographical constraints and disparities between locations of storage sites and regions where water is required, the estimated exploitable yield is 8.5 km3/year, of which 56 percent (4.8 km3/year) is already committed. This leaves 3.7 km3/year available for irrigation and other sectors. Dams are the core of significant progress towards the full development of the country’s water resources. The government has embarked on an aggressive large and medium-size dam construction programme in the country both for irrigation and other purposes. Total capacity is about 103 km3, but this includes 50 percent of Lake Kariba on the Zambezi River which is shared between Zambia and Zimbabwe and accounts for 94 km3 of this capacity. Not taking into consideration this shared dam, total capacity is thus about 9 km3. The overall groundwater resource is small when compared to estimates of surface water resources, mainly because the greater part of Zimbabwe consists of ancient igneous rock formations where groundwater potential is comparatively low. The estimated groundwater potential is between 1 and 2 km3/year. Four aquifer systems of relatively high groundwater potential are known and these are:
Water use Total water withdrawal was estimated at 4.2 km3 in 2002. Agriculture is the greatest water user in Zimbabwe accounting for 79 percent of total water use (Table 2 and Figure 1). Agricultural water uses are for irrigation, fish farming and livestock watering. Irrigated agriculture will continue to dominate the water demands for Zimbabwe in the foreseeable future. International water issues Zimbabwe is cooperating with other members of the Southern Africa Development Community (SADC) on the shared management of the region’s river systems. The country is a signatory to the recent Shared Water Course Systems Protocol, which provides the basis for the management of international rivers in SADC. The country is actively participating in the formation of the Limpopo and Zambezi basin commissions which will oversee joint management of these international rivers. Irrigation and drainage developmentEvolution of irrigation development Irrigation development has been considered of high importance to the country by all successive governments in Zimbabwe. Before independence in 1980 the then government invested heavily in dam construction and irrigation infrastructure although this mainly benefited the large-scale commercial farmers. From 1980 onwards the new government recognized the importance of extending the benefits of irrigation to the small-scale farming sector and intensified its efforts in that direction. The trend has been to promote farmer-managed smallholder schemes, although government-managed and jointly-managed schemes were also developed. The irrigation potential for the country is estimated at 365 624 ha, which takes into consideration only the available internal renewable water resources and not water from the Zambezi and Limpopo border rivers. Water is far a greater constraint than land as the overall area of soils classified as irrigable in Zimbabwe is estimated at 600 000 ha. The estimate for irrigation potential does not take into account the economic, technical or social feasibility of further irrigation development. In 1999, it was estimated that the total equipped area under irrigation was 173 513 ha (Table 3). These are full or partial control irrigated areas and refer to formal irrigation, i.e. those schemes that are usually developed, controlled and operated by the government on behalf of smallholders or the government itself, or by owners such as commercial farmers and estates (Figure 2). Out of this area, 49 647 ha or 28.6 percent is equipped but not functional because the equipment was damaged during the current land redistribution exercise. This leaves 123 866 ha as the operational area under irrigation in the country. Because of its informal nature, micro-scale irrigation, including irrigation on dambos, is not usually included in official estimates of the total irrigation area. Estimates of this area vary from 20 000 to about 50 000 ha. This type is called informal irrigation. Due to the dualistic nature of Zimbabwean agriculture there is almost no intermediate position between the large-scale and the small-scale farmers. Four broad categories of farming sectors can be identified as far as full or partial control irrigation is concerned in the country (Figure 3). These are:
Of the total irrigated area in Zimbabwe it was estimated in 1999 that 112 783 ha was under sprinkler irrigation (including centre pivots), 46 849 ha under surface irrigation and 13 881 ha under localized irrigation (Table 3 and Figure 4). Most formal irrigation schemes in the country depend on water stored in small- and medium-sized dams. Other important water sources are boreholes/deep wells, direct river diversion, shallow wells/springs and sand abstraction systems (a technique for extracting water from sand layers in river beds through a network of perforated pipes buried in the river bed which collects water into a sump from which it is pumped). Opportunities also exist in the country for the cultivation of wetlands or dambos. These cover a national area of 1.28 million ha, of which about 260 000 ha are in communal areas and the remainder in commercial farming areas. Only around 20 000 ha are cultivated in the communal areas (Table 3 and Figure 5). Although local research has confirmed the safety and advantages of dambo cultivation there is still no enabling national legislation and policy to promote their sustainable use. Water harvesting is another important activity in the country. In-situ techniques are the most commonly practised and are dominant in the drier natural regions IV and V. The most common systems are the use of infiltration pits, tied furrows, dead level contours, potholing and fanya juus. Despite the obvious benefits of water harvesting in the country, as claimed by farmers and researchers, there is still a lack of quantitative data the extent of its use in the country and of local scientific information on how the various techniques are performing. Role of irrigation in agricultural production, the economy and society About 70 percent of the population of Zimbabwe depends on agriculture for food and employment. However irrigation is important for successful crop production in the country as the greater part of the country (NRs III, IV and V) receives inadequate rainfall for agriculture. Even in the wetter NRs I and II mid-season droughts are common making supplementary irrigation necessary. Supplementary irrigation is also used to extend the growing season of certain crops or ensure the early planting of such crops as tobacco and cotton. The major irrigated crops in the country are wheat, cotton, sugar cane, tobacco, soybeans, fruit, vegetables and maize (Table 3 and Figure 6). Crops grown under irrigation constitute almost half of the total value of the crops marketed. Crop yields under irrigation have been shown to increase greatly as compared to yields from dry land (Table 4). In Zimbabwe, the figures shown in Table 5 and Table 6 are indicative values of crop water requirements used for irrigation planning purposes. Overall irrigation efficiencies on irrigation schemes in Zimbabwe are generally about 45 percent or lower for surface schemes, between 65 and 70 percent for sprinkler schemes and from 80 to 90 percent for drip schemes. The cost of irrigation development in the country is normally site specific. It also depends on the type of technology to be installed, whether it is a new or rehabilitated development or and whether it is a single-user commercial scheme or a multi-user smallholder scheme. Normally the costs are divided into capital, operation and maintenance (O&M) (Table 7). Status and evolution of drainage systems Drainage issues have received less prominence and are less documented in the country compared with the development of new irrigation infrastructure. Drainage is seasonal in the country and the most common drainage system found is surface drainage and this is installed in both large-scale commercial and smallholder irrigation schemes as part of the water management system. Drainage systems are mainly found in surface irrigation schemes. Generally the drainage systems are made up of field drains (open canals) which collect excess irrigation water and rainfall runoff from the fields. The field drains discharge into a network of secondary drains which in turn discharge into the main (primary) drain which delivers drainage water out of the scheme. A general rule for the country is that 12 mm must be drained in 24 hours, which equals a steady drainage flow of approximately 1.4 l/sec per ha. The main problem with surface drainage systems in all irrigation schemes is the lack of proper maintenance resulting in below optimum functioning of the systems. In smallholder irrigation schemes farmers have a tendency to plant fruit trees or dump manure in the drains rendering them non- functional. Water management, policies and legislation related to water use in agricultureInstitutions Several government institutions, parastatal agencies and other non-governmental organizations are involved in irrigation and water management in the country. The major ones are as follows:
Water management At the national level the responsibility for the planning, coordination, management of water resources and the delivery of water is vested in ZINWA in conjunction with the Catchment Councils. ZINWA is supervised by its parent ministry MRRID. There are seven Catchment Councils in the country and each is supposed to represent all stakeholders in a given catchment area. Irrigation schemes, both smallholder and large-scale commercial schemes, are represented in some of these councils. In terms of irrigation scheme management generally, and water management in particular, the large-scale commercial schemes including estates and plantations are managed and run by their private owners. ARDA is responsible for managing the schemes under its jurisdiction on behalf of the government. Within the smallholder irrigation schemes, three broad types of management can be found: government-managed, farmer-managed and jointly-managed schemes. Government-managed schemes are developed and maintained by the government. Farmer-managed schemes are developed by the government but owned and managed by the farmers with no external assistance. In the case of jointly-managed schemes, the farmers and the government share the financial responsibility for operation and maintenance. In terms of scheme numbers, it is estimated that about 50 percent of the schemes are farmer-managed, about 32 percent government-managed and 18 percent jointly-managed. However, in terms of hectares the government is still managing a bigger area given that most farmer-managed schemes tend to be small. At the level of farmers in smallholder irrigation schemes, Irrigation Management Committees (IMCs) have been established to help encourage farmer management. The government’s policy since 1980 has been to promote farmer-managed schemes where possible. The IMCs have no legal standing and their effectiveness varies from scheme to scheme. The departments of AREX and DOI play a central role in providing extension and training to the irrigation sector. These departments are present at the provincial level and, in the case of AREX, also at the district level. The DOI also has an approved structure at the district level. In most irrigation schemes in the smallholder sector, there is at least one full-time extension worker from AREX. Farmer organizations and unions also provide training and extension services to irrigators. The main farmers’ unions are the Commercial Farmers’ Union (CFU), which represents large-scale commercial farmers, and the Zimbabwe Farmers’ Union (ZFU), which represents smallholder farmers. Finances Large-scale commercial irrigators, including estates and plantations, source funding for irrigation development privately. However, irrigation development for ARDA, smallholder irrigation schemes and dam construction by ZINWA have been traditionally provided by the government through funds allocated under the Public Sector Investment Programme (PSIP). The government has also set up a means of obtaining credit, namely the Agricultural Development Assistance Fund (ADAF) which is administered on behalf of the government by AGRIBANK, a commercial bank. ADAF offers credit for agricultural projects including irrigation development, but is charging concessionary interest rates. Both large and small farmers can borrow from this fund. Dam construction costs are unusually high and from time to time the government has shared the cost of particular storages with private investors who have received special allocations in return for their contribution. Until recently, irrigation development in the smallholder subsector has also received substantial financial support from donors and non-governmental organizations (NGOs). Large-scale commercial farmers and ARDA pay for their O&M costs. Within the smallholder farmer-managed schemes, farmers also pay for their O&M costs. On government-managed schemes, farmers pay the DOI an annual maintenance fee. In turn, the DOI receives an annual financial allocation from the government to subsidize these schemes by paying their O&M costs. Farmers in the country now pay ZINWA for irrigation water and the billing is based on the volume of water used per month. Irrigation schemes are being supplied with water on the basis of water agreements with ZINWA. Policies and legislation Several attempts have been made to formulate an irrigation policy for the country as evidenced by the writing of the Derude Policy paper on small-scale irrigation schemes (1983) and the FAO Irrigation policy and strategy document (1994). However neither of these documents have been formally endorsed by the government as policy on irrigation development. National policies and objectives for the agricultural sector are set out in Zimbabwe’s Agricultural Policy Framework (ZAPF) 1995-2020. ZAPF clearly states the government’s policy on water resources and irrigation development. Specific national policy objectives include:
The Zimbabwe Environmental Impact Assessment Policy of 1997 stipulates that irrigation is a prescribed activity which shall not receive the required authorization to proceed from the authorities unless and until the authorities have exempted the activity from the requirements of an Environmental Impact Assessment (EIA) or has granted EIA acceptance. Recent milestones in water- and land-related legislation are:
Environment and healthSurface water in Zimbabwe is usually of good quality for irrigation: generally conductivity is less than 500 micro siemens/cm. Groundwater on the other hand tends to be more variable in quality, with some being saline, sodic or saline sodic. Current knowledge about the quality of groundwater in the country is limited. Chemical analyses of water are done before the implementation of drip systems but are rarely done for surface and sprinkler systems. Poor drainage and salinity are not a major problem in irrigated areas in Zimbabwe, although it has been observed in some schemes under surface irrigation and it is normally associated with poor land levelling and poor water management or the use of poor quality irrigation water. There is a general increase in the use of agrochemicals in the country due to the intensification of crop production. It is thought that the regular use of commercial levels of agrochemicals is an occupational risk for irrigation farmers and increases the risk of contamination of both surface water and groundwater resources. However, data on water analysis showing agrochemicals levels in natural water sources in Zimbabwe are not obtainable and it is thus difficult to establish the extent of pollution due to irrigated agriculture. In Zimbabwe the net effect on human health of irrigation development tends to be positive. There is an improvement of the nutritional status of the people both on the scheme and in the surrounding area. Indirectly, benefits are twofold: i) because of the economic progress resulting from irrigation, communities can afford better health care; ii) the upgraded infrastructure (roads, electricity, etc.) that accompanies irrigation ensures better basic health services such as child immunization, family planning and mother and child health. However, despite the net positive effect on human health, irrigation (especially surface irrigation) in the country is associated with an increased risk of malaria, schistosomiasis, enteric diseases like diarrhoea, agrochemical poisoning, skin and eye diseases. Prospects for agricultural water managementDue to recurrent droughts in the past few years the government has realized the importance of irrigation to the country and as a result has declared irrigation as strategic to the country’s agricultural development. This means that wherever possible, agriculture in the country will be irrigation-based. In the past irrigation development has favoured the traditional large-scale commercial farmers. However, of late the benefits of extending this development to the smallholder subsector have been realized. The current trend is to focus irrigation development on the smallholders, especially in the context of the current government’s land redistribution exercise where large-scale commercial farms are being acquired for the resettlement of smallholders. Wherever possible, the government is promoting farmer-managed irrigation schemes. Enabling new legislation to support this development has been recently enacted in the form of the New Water Act (1998), the Land Acquisition Act (2000) and the Environmental Management Act (2002). The ZAPF (1995) clearly states the government’s future policy on irrigation and water. To allow a more coordinated development, institutional reforms within government are under way to bring all irrigation functions under a single and stronger government department. The limiting factor in irrigation development in the country is water availability and lack of capital. Provision of water depends entirely on expensive storage works. However due to the past uncoordinated approach to irrigation development, many irrigation dams have been constructed without the corresponding irrigation infrastructure. The short-term plan is to utilize all the water in existing dams reserved for irrigation before embarking on new dam construction. The tradition has been to allocate irrigation water from dams based on a 10 percent risk factor. This is rather conservative and is unlike the rest of the world. Current thinking is that one way of increasing irrigated area at minimal cost could be to lower the reliability levels of water from existing dams by accepting a 20 percent risk factor rather than the traditional 10 percent. More recently, donor funding in irrigation has been declining but the government has stepped up funding for irrigation from its own limited resources. Due to the government’s land reform, many new farmers with no prior experience of irrigation have been allocated plots on former commercial farmers’ irrigated land. The future challenge for the country is to train these new farmers in irrigation so that they will be able to produce more efficiently and on a sustainable basis. In some cases there is need for massive re-planning of some of the allocated irrigation systems to convert them from single-user systems to multi-user systems. Main sources of informationDepartment of Agricultural Engineering and Technical Services. 2002. Report on the status of irrigation development in Zimbabwe. Harare. FAO. 1994. Zimbabwe: Irrigation Policy and Strategy. Harare. FAO.1999. Zimbabwe: Smallholder Irrigation Development Project. Preparation Report, Volumes 1-3. Report No 99/030 ADB-ZIM . Rome. IFAD. 1997. Smallholder Irrigation Support Programme, Appraisal Report, Volumes I - II, Report No. 901-ZW. Rome. Makadho, J. 1991. Procedure for a farmer’s application for a water right. Department of Agricultural, Technical and Extension Services (AGRITEX). Harare. Ministry of Lands, Agriculture and Rural Resettlement. 1995. Zimbabwe’s Agricultural Policy Framework: 1995 -2020. Harare. Ministry of Lands, Agriculture and Rural Resettlement. 2001. The Agricultural Sector of Zimbabwe: Statistical Bulletin - 2001. Harare. (Profile as published in Water Report no.29, 2005)
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