Read the full profile
Irrigation and drainage
Evolution of irrigation development
There are traces of an ancient terraced system in Nyanga, Eastern Zimbabwe, with furrows, reservoirs and aqueducts pointing to pre-colonial irrigation techniques, as well as in the Limpopo river catchment, the Lowveld and the Drakensberg escarpment (Tempelhoff, 2009). In the 19th century, dambo, or vlei, mbugas, and fadama cultivation (lowlands and valley bottoms) was widespread and intensive, despite the fact that it was banned by the colonial authority in early 1900s, and cultivation the those lowlands and inland valley bottoms continues still today (Mabeza et al., 2012). From 1912 onwards smallholders developed their own irrigation schemes, encouraged by missionaries, to fight famine. The Manicaland province schemes were the first ones to be developed. However, from 1928 onwards the colonial government started to assist them and soon took over the schemes’ management, imposing crops and forbidding rainfed farming (Rukuni, 1988). After the 2nd World War, new irrigation schemes were developed to settle black farmers displaced from areas designated for white commercial farmers. Due to lack of involvement in management and rising costs to be paid to the government, the smallholders deserted these schemes, which became uneconomic. As a result; from 1960 to 1980 there has been almost no irrigation development for smallholder farmers, but the government invested heavily in dam construction and irrigation infrastructure for the large commercial farmers. But the 1981 and 1984 droughts decided the newly independent government to encourage irrigation and extend the benefits of irrigation to the smallholder 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, of which 49 647 ha or 28.6 percent was equipped but not functional because the equipment was damaged during the ongoing land redistribution exercise. This left 123 866 ha as the operational area under irrigation in the country. In addition, irrigation in dambos, either equipped or not, was estimated between 20 000 to about 50 000 ha.
The FTLRP redistributed the previously privately-owned irrigation schemes of large commercial farms to multiple smallholder farmers, many of whom had no prior experience with irrigation (USAID, 2012). In addition to lack of training, some irrigation infrastructures have also been dismantled during the land redistribution, either by those leaving taking the equipment with them or by those arriving who did not believe initially that they would stay on the land in the long term.
An exact inventory of the irrigated areas, either equipped or actually irrigated, is not available. The Department of Irrigation estimates the area equipped for full control irrigation at 150 000 ha in 2014, divided between 26 550 ha surface irrigation, 112 500 ha sprinkler irrigation and 10 950 ha localized irrigation (Table 7 and Figure 2). But the equipped area that is actually functional and the actually irrigated areas seem much lower (Table 8): 38 percent of the sampled wards–administrative subdivision of districts and provinces, surveyed for the annual vulnerability assessment–with irrigation schemes had functional schemes, 30 percent had partially functional ones and 32 percent had not functional ones (FNC, 2012). In 2012, 102 000 ha were equipped for irrigation and operational (GoZ, 2013). Out of this functional area, another estimation based on satellite imagery, indicates that 51 000 ha was actually irrigated in 2012 (WB, 2014). Despite the uncertainty implied with satellite imagery and the very punctual assessment it represents, the figure tends to confirm the low rate of actually irrigated areas. The actually irrigated area seems to be concentrated in the Save and Runde catchments: satellite image shows 40 000 ha out of the total of 51 000 ha are located in the south-east Lowveld (WB, 2014). In addition, Mashonaland West had the highest number of wardswith non-functional irrigation schemes (67 percent), and Matabeleland North the highest number (54 percent) of wards with functional irrigation schemes (FNC, 2013). In addition, equipped dambos are estimated at 25 000 ha (Table 7 and Figure 3).
The ratio of wards with functional and partly functional schemes has a positive trend with a strong increase between 2012 and 2014 (Table 8), although it’s only a partial estimation as not all wards were surveyed each year. However, some of the 32 percent non-functional schemes in 2012 had been smallholder community irrigation schemes rehabilitated since 2009. Indeed, a double challenge faces the new irrigators: the rehabilitation of the irrigation infrastructure when required, as well as the difficulties associated with the management of common irrigation infrastructures through associations that are sometimes still to be established.
Four broad categories of irrigation can be identified in the country:
- Large-scale commercial schemes: refers to land owned by private individuals or groups including estates and plantations. Before the FTLRP, all were operated by white farmers. Some “indigenous large-scale commercial schemes” have now emerged (UNESCO, 2008).
- ARDA (Agricultural and Rural Development Authority) schemes: refers to parastatals responsible for running government-owned estates and farms, and for agricultural and rural development in rural areas.
- Smallholder irrigation schemes: refers to a group of farmers irrigating together, even before the FTLRP, and sharing the same water source and main supply line. However there is individual control of irrigation and farming activities by each farmer in his/her plot.
- A1 and A2 irrigation schemes: this new kind of irrigation scheme has emerged as a result of the FTLRP, splitting the commercial schemes and increasing the area under smallholder irrigation. The A1 group of farmers irrigate small areas at times with shared infrastructure and the A2 groups are commercial irrigators. There is sometimes an overlap between A1 and A2 groups.
The extent of each of these categories is unknown after the FTLRP. However, there has been a significant decrease in the extent of large-scale commercial schemes to the benefit of the small farmers in A1 and A2 groups.
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).
The traditional cultivation of non-equipped wetlands or dambos also still exists. It is estimated that around 15 000 ha are cultivated in 2014 (Table 7).
Irrigated schemes to be operated with treated wastewater have been developed in the main cities over the last 30 years for crop and pasture (Harare/Chitungwiza/Norton, Bulawayo, Gweru, Kwekwe, Kadoma). However, these schemes are mostly not functional anymore (WB, 2014). It is estimated that in 2012 about 2 600 ha was equipped for irrigation using treated municipal wastewater (UNWAIS, 2012).
Water harvesting is another important activity in the country. In-situ techniques are the most commonly practised and are dominant in the drier regions. The most common systems are the use of infiltration pits, strip catchment tillage, earth basins and contour ridges. However, there is no data on the extent of its use in the country. Conservation agriculture was estimated to be practiced on 332 000 ha in 2013, representing over 8 percent of the cultivated area.
Role of irrigation in agricultural production, the economy and society
The number of non-functional irrigation schemes in rural communities evidences the high dependency on rainfed cropping in rural Zimbabwe (FNC, 2013). Before the FTLRP, irrigated agriculture was a major contributor to the agricultural GDP, with almost half of the marketed crops being irrigated, although irrigation was practised on around 5 percent of the cultivated area. The major irrigated crops in the country were wheat, cotton, sugarcane, tobacco, soybeans, fruit, vegetables and maize. A recent irrigated crop calendar is not available. The latest one prepared by AQUASTAT in 2012 dates back to 1999.
All wheat and sugarcane grown in Zimbabwe is under irrigation, while 70 percent of coffee and 55 percent of tea are under irrigation. All commercial wheat produced in Zimbabwe is grown under full irrigation during winter. Traditionally grown by large-scale commercial farmers due to the high level of inputs required, the area under cultivation of wheat has decreased after the FTLRP from 37 to 70 000 ha prior 2008 to 12 000 ha in 2009 (GoZ, 2013). Yields have also decreased significantly (from 5.4 tons/ha in 2001 to only 2 tons/ha in 2009) as a result of the non-functional irrigation equipment and even more frequent electricity shortages (AFD, 2012).
Sugarcane production in Zimbabwe is well below the prior FTLRP level, with 475 000 tons in 2012/2013 and 372 000 tons in 2011/2012. The traditional sugar production estates are adapting to the land reform, for example Tongaat Hullets estate has an ongoing project that aims to allocate 15 880 ha of land to private farmers. Mkwasine estate is farmed by smallholder farmers on 8 200 ha and includes Chapiwa, a resettlement scheme. Another main sugar growing estate is Mpapa, cultivated by a group of 17 farmers with 35 ha each.
Women and irrigation
Women play an important role in agriculture and it is estimated that 70 percent of smallholder farmers are women. A survey indicated that irrigation in smallholder schemes is also dominated by women, although only few are represented in their Irrigation Management Committees (IMCs) constituted by 80 percent men and 20 percent women. Women, who largely provide labour in the surveyed irrigation schemes, also look after children as well as other vulnerable groups, such as orphans and chronically ill persons. The fact that nationally 38 percent of the rural households include one member of these vulnerable groups has therefore a negative impact on the viability of these irrigation schemes (Mutambara et al., 2014).
Status and evolution of drainage systems
Drainage issues have received less prominence and are less documented compared to 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 surface irrigation schemes as part of the water management system. 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.
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.