Previous PageTable Of ContentsNext Page

Annex A-3 Mambanjeni Irrigation Scheme


Mambanjeni irrigation scheme is located in Gweru District of Midlands Province. It is one of the poorly performing farmer managed smallholder schemes in Zimbabwe. The scheme is 77.7 ha large with 164 plot holders, each holding between 0.3 ha and 0.5 ha. Established in 1987 by the government, the scheme has not managed to perform as expected. The agricultural performance has been poor with the crop yields being far below the expected levels. Incomes have been too low to sustain the day to day living of the participants. This poor performance has been directly due to the numerous technical and planning related problems, which affected the scheme right from the beginning. Frequent pump breakdowns, poor hydrant positioning and wrong lateral spacing has all contributed to the poor performance of the scheme. Farmers never participated in the planning and implementation of the scheme, but were only used as hired labour. Consultants who had no prior experience with smallholder irrigation made designs. AGRITEX and other local institutions were never involved in the planning of the project. In terms of operations, the DWR, which is responsible for maintaining the scheme and paying electricity bills, is failing to do so due to budgetary constraints. Electricity is frequently disconnected and infield infrastructure is in a very bad state indicating poor maintenance. All these issues need to be addressed for the scheme to function properly. The experiences with Mambanjeni scheme have brought with it very important lessons. Any future irrigation development should make sure that competent personnel are tasked to do the planning and farmers should be involved throughout the planning and implementation processes. In light of the failure of government departments to maintain irrigation schemes, it is important that any future development should prepare the handing over of these projects to the beneficiaries.


The scheme is located in the Lower Gweru communal area in Gweru District of Midlands Province. It is about 46 km north west of the town of Gweru. It falls in Natural Region IV, a region in which agriculture is severely limited by inadequate rainfall. This makes irrigation important in this region for any meaningful crop production. The scheme utilizes a semi-portable sprinkler irrigation system. It is divided into three blocks A, B and C having 47, 60 and 57 farmers respectively. Plot sizes are 0.5 ha in blocks A and B and 0.3 ha in block C.

Planning of the scheme

Following the construction of Insukamini Dam, the Government of Zimbabwe in 1986 initiated Mambanjeni irrigation scheme. The government had several objectives in initiating this scheme, namely to improve farm incomes, food security and cutting down on food handouts. The Department of Water Resources (DWR) was the lead government institution in the identification process.

The scheme was to draw its water from the then newly constructed Insukamini dam via a pick-up weir on Gweru River. A number of farmers were to be displaced from their dryland areas by the irrigation scheme. This move of displacing farmers was strongly resisted but after a series of meetings between the farmers and the government officials, an agreement was finally reached. The agreement was based on the understanding that the displaced farmers would get first priority in the allocation of plots, despite their capacity or inability to adopt the new technology. The rest of the irrigators were selected on the basis of willingness to participate.

The responsibility of planning the project was handed over to DAN Group, a private consulting company, under direct supervision of DWR. The consultants were responsible for designing the whole scheme, including both the headworks and infield works. Construction of the scheme was contracted out to a private civil engineering company without farmer involvement. Irrigators were only hired as casual labour.

The scheme started operating in 1987. However, numerous technical problems affected the scheme right from the beginning. Only one pump instead of two as per design was installed on the scheme. The pump could not cope with the demand. Furthermore, laterals and hydrants were wrongly positioned during construction. Frequent pump breakdowns affected the first whole crop on the scheme. This was a heavy blow to the farmers and they viewed irrigation as a useless non-adapted technology. They regretted why they accepted the technology in the first place. In 1991, DWR took up to rehabilitate the scheme. They tried to correct the infield designs and a second pump was put in place to rectify the situation. This move improved the system to the extent that the farmers could at least irrigate but there were still flaws in the system. As a result the scheme continued to perform poorly.

Social aspects

Land tenure and inheritance

Farmers practice full time irrigation with no other plots in the dryland. Plot allocation at the scheme is such that 100 plots are owned by female headed households (widows or divorcees) and 68 are owned by male headed households. If the female owner dies her her children inherit her plot and if it is a male owner the spouse will take over. If both parents pass away the children will inherit the plot. Farmers are comfortable with this land inheritance system.

Relationship with outsiders

Irrigators live harmoniously with the surrounding non-irrigators. In fact, there is some strong interdependence between the two groups. Non-irrigators provide labour in return for vegetables and wheat. During times of drought the scheme provides some considerable amount of food to the non-irrigators. However, the scheme can not provide the expected amounts of food, due to technical problems affecting the scheme.

Scheme operation, maintenance and management

Irrigation Management Committee

The IMC, which was formed at the beginning of the scheme, is responsible for the overall management of the scheme. Apart from enforcing the scheme bye-laws, the IMC takes a leading role in the determination of the cropping programmes, with assistance of AGRITEX. In terms of water management, the IMC acts as a link between DWR and the irrigators. They also represent farmers at various meetings with government institutions. When it comes to marketing, the IMC sometimes organize transport to ferry produce to the markets as far as Gweru and Bulawayo. The overall picture, which came out, was that the IMC is doing a commendable job.

The composition the IMC is as follows:

  1. Chairperson and vice chairperson
  2. Secretary and vice secretary
  3. Treasurer
  4. Seven committee members.

The secretary, vice secretary and treasurer are all women. This represents 25% women in the IMC. Most women interviewed viewed this as an unfair representation of women in the IMC, considering that the majority of the plot holders are women. About twenty farmers who were interviewed to give their perceptions on the functions and effectiveness of the IMC were of the feeling that the IMC was performing well. They regarded them as people who know what they are doing. The only problems were the technical problems affecting the scheme.

In addition to the IMC, there are three block committees, each responsible for a particular block, The block committees report directly to the IMC. Each block committee comprises of a Chairman, Secretary and Treasurer. The gender composition for the block committees is given in Table 25.

Gender composition for the block committees at Mambanjeni irrigation scheme (Source: AGRITEX Extension Worker, 1998)

Post Block A Block B Block C
Chairman Male Male Male
Secretary Female Female Female
Treasurer Male Male Female

The block committees are responsible for solving problems affecting each individual block. They control the use of water and they report to the IMC on all matters affecting the blocks. If a problem, a dispute or a grievance arises in the block, the block committee takes first responsibility to solve it and if it fails it takes the matter up to the IMC. Meetings are held once a month between the IMC and the block committees. The IMC and the block committees are elected on a two-year term basis after which new elections are held.

Water management

The resident Extension Worker offers assistance to the farmers in terms of irrigation water management. He in turn is backstopped by the irrigation engineers based at the AGRITEX provincial office in Gweru who prepare the irrigation schedules for the scheme.

Farmers pay water charges of Z$ 185/1000m3. In 1997 they paid Z$ 900 for 0.5 ha. The general feeling of the farmers about the water charges is that they are unable to meet them. They regarded their incomes as too low to permit the payment of such huge sums.

Electricity bills

DWR is responsible for the payment of electricity bills. The bills range from about Z$ 23 000 to Z$ 40 000 per month when the scheme is fully operational. There are always delays in payment of the bills leading to frequent electricity disconnection. DWR has been talking about handing over the bills to the farmers. However, with the current level of production farmers can not take up the bills.

Repairs and maintenance

DWR is also responsible for maintaining the pumping unit, the conveyance and the infield infrastructure. The department is failing to discharge its obligations due to budgetary constraints. As a result DWR takes time to respond to pump breakdowns thus affecting the smooth running of the scheme. Furthermore, the department for unexplained reasons has stopped the repair and maintenance of the infield infrastructure.

Institutional support

Various institutions facilitate the day to day management of the scheme. These include AGRITEX, the DWR and the IMC.


AGRITEX is responsible for offering technical advice on cropping and water management aspects. Currently there are two Extension Workers for the scheme. The farmers appreciated the role of AGRITEX in the management of the scheme.

Department of Water Resources

DWR is responsible for the operation and maintenance of the pumping unit. A water bailiff, employed by DWR, opens and closes water at the farmers' request. There are problems between the farmers and the water bailiff. Farmers accused the bailiff of not being sensitive to their demands. He is not willing to work after 17.00 hours, arguing that he finishes work at 16.45 hours, and sometimes he opens water very late.


AGRITEX has run several training programmes for the irrigators and has taken them on study tours to other operational schemes in the country. The farmers have learnt a lot from such arrangements.

Agricultural performance

The crops being grown under irrigation are grain maize and beans in summer, wheat and green maize in winter. The cropping patterns for the 0.3 ha and 0.5 ha plots at the scheme are given in Table 26 and 27 respectively.

Cropping pattern on a 0.5 ha plot at Mambanjeni irrigation scheme (Source: Extension Worker's record book, 1998)

Crop Area (ha) Area as % of plot size
Summer: 0.25 50
- Maize 0.25 50
- Beans 0.25 50
Winter: 0.25 50
- Green Maize    
- Wheat    
Total 1.00 200

Cropping pattern on a 0.3 ha plot at Mambanjeni irrigation scheme (Source: Extension Worker's record book, 1998)

Crop Area (ha) Area as % of plot size
Summer: 0.15 50
- Maize 0.15 50
- Beans 0.15 50
Winter: 0.15 50
- Green Maize    
- Wheat    
Total 0.60 200

Tables 26 and 27 reveal that farmers plan for a 200% cropping intensity, which is good for irrigated agriculture. However this commendable intensity has not been translated into increased production levels at the scheme. Farmers have tried to implement the programme but with limited success. For example, during the period 1987 to 1990 farmers were operating as dryland farmers since the irrigation system was not operating well.

After scheme rehabilitation, production levels were again too low in 1991 and 1994. This was due to frequent pump breakdowns and flaws in the infield designs. Lack of inputs also worsened the situation. Most farmers on the scheme are not credit worthy because of arrears to the AFC, accumulated when they were still dryland farmers. Farmers found it difficult to acquire at least a bag of fertilizer for 0.25 ha of maize. The crop yields were low and were estimated at 0.5-2 tons/ha for maize, 0.8-5 tons/ha for wheat, and 0.6-1 tons/ha for beans.

In 1997, another problem affected the scheme. Gweru city municipality released some thick sewerage effluent into Gweru River, which supplies the weir used for irrigation. This thick waste had an effect of clogging the suction pipe of the pump there by making it impossible to pump water to the scheme. This problem continued for most of 1997. Irrigators lost the whole maize crop. They demanded compensation from the municipality, but they were not paid. Farmers accuse the city fathers of poor planning and being irresponsible. The problem has since been rectified.

The year 1998 witnessed numerous pump breakdowns. The wheat crop was heavily stressed and average yields of 2 tons/ha were reported. This yield is too low for an irrigation scheme. The green maize was only planted in October, which is too late. A question was raised on why the farmers were not diversifying into lucrative horticultural crops. The answer to that was:

"Tingarima sei mirivo isusu tisina chekudya. Zvirinani kurima gorosi ne chibage zvinotipa sadza." This literally means " How can we produce horticultural crops when we do not have enough to eat. It is better to produce maize for our daily meals".

This seems to be justified given the numerous pump breakdowns occurring at the scheme. Horticultural crops are marketed on competitive markets where quality is of paramount importance. This can not be achieved at this problem-ridden scheme. With low input levels and frequent water shortages, only poor quality vegetables can be obtained.

Commercial aspects


The produce from the scheme has two major marketing channels, namely the local market and the Gweru town wholesale market. Grain maize and wheat are locally marketed. The dryland farmers usually produce a good crop once in every five years, so they rely heavily on the scheme for grain when it is operating well. The irrigators either sell the grain for cash or exchange the grain for labour. It is important to note that only a small proportion of the grain produce is marketed, the rest is retained for subsistence purposes. This is because production from the scheme is too low. Beans are produced on contract for a private company, Olivine. Transport is sent directly to the scheme to collect the produce. Prices are negotiated when farmers are about to harvest. This is the only crop giving farmers some meaningful returns. Green maize is sold in Gweru and Bulawayo towns. Farmers hire trucks as a group to ferry their produce to the market. Sometimes buyers come straight to the scheme with their own transport. Farmers are usually disappointed when they to the Gweru or Bulawayo markets. For example, in 1997 they hired a truck to Bulawayo only to come back with little income, as their poor quality could not compete on the market. The same happened to the bean crop, which could not be sold because of poor quality.

Input acquisition

Farmers get inputs from local stores in the area. They use donkey or ox driven carts to carry the inputs.

Farm income analysis

The incomes obtained from the different crops grown are very low. The reasons for such low incomes are the marketing problems farmers face because of their poor quality produce. The total production levels for crops are too low to cover the costs. Incomes for the thirty farmers who were interviewed on the scheme range between Z$ 1 000 - Z$ 4 000 net per farmer per year. The Extension Worker gave the same estimates. Beans is the highest paying crop, followed by green maize. Grain maize and wheat have negative gross margins.

Financial and economic analysis

Financial and economic analyses were carried out to assess the viability of the Mambanjeni scheme. Financial analysis in particular examines the viability of the project from the point of view of the participants. It compares the benefits and costs associated with the project. Market prices are applied throughout the analysis. The analysis utilizes cash flows (Table 28). The cash flows include the average gross margins as of 1997. The 1997 energy costs are also considered in the analysis. The repair and maintenance costs are derived from the costs incurred by DWR. The replacements costs incurred from the beginning of the scheme up to 1997 have been also included. The investment costs have been annualized at 9.75% interest for 20 years. Extension, monitoring and evaluation have been included as cash outflows. All the costs and incomes have been deflated by 20% inflation rate to give the estimates at 1987 prices. The whole analysis was subsequently done at constant 1987 prices. The FIRR could not be calculated, because the cash flows are negative. The NPV was found to be -Z$4 373 022 indicating that the project is not viable. This non-viability is due to a number of factors, including low yields, low-income levels and lack of adequate repair and maintenance of the scheme.

Economic analysis assesses the project from the point of view of the society. Shadow prices, which reflect the real value of the project, are used in the analysis. To arrive at these prices, conversion factors have been used to adjust the financial prices. This adjustment is necessary to correct for market distortions.

The opportunity cost of capital used is 8.5% (a rate recommended by the Ministry of Finance of Zimbabwe). The EIRR for the project could not be calculated, because the cash flow figures are negative. The NPV in economic terms was found to be minus Z$ 3 256 980, showing that the project is not viable from an economic point of view.

Discounted cash flow analysis for Mambanjeni irrigation scheme.

Year Investment costs (Z$) Energy costs (Z$) Water charges (Z$) Replacement costs (Z$) Repair & maintenance costs (Z$) Extension costs (Z$) Irrigation income (Z$) Incremental benefits (Z$)
1987 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1988 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1989 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1990 536 897 69 770 27 036 14 350 75 100 50 000 97 679 -675 475
1991 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1992 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1993 536 897 69 770 27 036 21 000 75 100 50 000 97 679 -682 125
1994 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1995 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1996 536 897 69 770 27 036   75 100 50 000 97 679 -661 125
1997 536 897 69 770 27 036 23 000 75 100 50 000 97 679 -684 125
NPV               -4 373 022

Socio-economic impact

Mambanjeni irrigation scheme can be viewed as one of the unsuccessful smallholder projects in Zimbabwe. From the analysis made in the preceding sections, it is clear that the project failed to meet its paramount objective of improving the standard of living of the farmers. The incomes derived from the irrigation scheme are very low. The monthly incomes of Z$ 90 - Z$ 333 per farmer obtained in the scheme are too low to justify the huge investment costs in irrigation. The incomes are lower than the average monthly salary of Z$ 600 obtained by a farm worker on a commercial farm. The monthly income can not even cover the energy costs which averages Z$ 420 - Z$ 500 per month for a 0.5 ha plot.

Due to the low incomes, the male household heads prefer to work in towns. Of the male headed households on the scheme over 90% of the men work in town. This is perceived as the only means to generate income for the families. The irrigation project cannot meet school fees and other financial needs of the families. Mambanjeni scheme is unable to offer farmers continuous employment throughout the year. Most farmers tend to allocate part of their time to other off-farm activities. This means that the scheme has failed to offer essential incentives for the farmer to be employed full time. However, irrigators sometimes hire labour from the village, which is paid in kind. This is a positive contribution to the development of the area, which could be even more important had the scheme been operating well.

The scheme also contributes positively towards household food security. The maize and wheat that are locally marketed are important for the dryland farmers who can only afford to get a meaningful harvest once every five years. During the scheme's successful seasons villagers do not have to travel all the way to Gweru town to buy maize meal. The payment of labour in kind also ensures the availability of food to the surrounding villages.

Local stores are benefiting to some extend from the irrigation scheme. The fertilizers and chemicals, which are demanded from the local dealers, are an example of the backward linkages provided by the scheme. These dealers have also taken advantage of the electricity line, which was erected to serve the scheme. The whole local business centre is now electrified.

From an economic point of view the scheme has not contributed much towards the well being of the society. In fact, the scheme is relying heavily on government subsidies. From the way it is operating it would be difficult to hand over the scheme to the farmers.


Several factors have been identified to contribute to the overall failure of Mambanjeni irrigation scheme. Some of the important factors revealed by the study are:

Poor planning: (i) The non-involvement of farmers during the planning and implementation instilled a sense of dependence in farmers; (ii) The involvement of consultants with no experience in smallholder irrigation planning was a mistake on the part of government. The irrigation system designed by the consultants is not ideal for farmer management; (iii) The non-involvement of AGRITEX and other institutions who have experience with smallholder schemes in the planning stage was a major error on the part of the planners.

Poor designs: Irrigation system designs made by the consultants were substandard. The construction itself, which was supervised by the DWR, was poorly done. The hydrants are wrongly placed and the lateral spacing selected is not correct. The poor designs have contributed to water management problems on the scheme.

Poor maintenance of the system: There is poor repair and maintenance of the system by DWR, due to financial constraints. The department has stopped the repair of infield works and electricity bills are always paid late leading to frequent power disconnection on the scheme. This poor institutional back up has negatively affected the performance of the scheme.

Low level input use: There is very little use of inputs by the farmers and when inputs are used the levels are well below the recommended levels. This has resulted in reduced yields and incomes. Farmers do not have the capital to buy inputs. AFC is unwilling to offer credit because of outstanding arrears the farmers have which they acquired while still practicing dryland farming.

Marketing: Farmers lack the necessary marketing skills. They have been cheated twice by unscrupulous dealers, who collected their crops and promised to come back and pay. The dealers never came back and the farmers lost out.

While the scheme is performing badly, there are a number of strengths that work in favour of it. These factors can actually make the scheme viable if the technical problems are corrected. The strengths are:

The interventions needed for Mambanjeni scheme to perform well are more of a technical nature. There is need to rehabilitate the whole system. Reliable pumps should be installed. Clarification of repair and maintenance responsibility is important. If possible the scheme should be handed over to the farmers after full rehabilitation.

Previous PageTop Of PageNext Page