JG Afrika was appointed by the Department of Agriculture, Land Reform and Rural Development (DALRRD) to undertake the feasibility, design, and construction monitoring for the development of the Nkungumathe Irrigation Scheme in the Nkandla Local Municipality of the King Cetshwayo District Municipality. The 18ha greenfields development will be used by members of Nkungumathe community to grow vegetables for food security and to generate income by selling excess produce.
There are many considerations for the development of an irrigation scheme. They include environmental requirements and constraints, water supply, and crop selection and associated agricultural potential. This is in addition to community interactions and skills development, as well as structural and water engineering.
There were many key challenges that were encountered during the development of this irrigation scheme.
This included the need to accommodate water demand flexibility during irrigation considering varied requirements across 11 plots that will be managed by 11 local co-operatives.
There was also a large elevation difference of up to 100m between the water source and land parcels identified for development. Conventionally, this would result in extremely high energy costs for the small-scale farmers.
Moreover, the design had to be simple and consistent to ensure the sustained use and management of the infrastructure by the emerging farmers. In addition to ensuring acceptance of the system by the local co-operative members, they would have to receive hands-on training in its operation and maintenance.
The infrastructure developed for the Nkungumathe Irrigation Scheme included a reinforced concrete pump station building and abstraction works on the Mhlatuze River. It features two 30kW centrifugal pump sets, a 250mm diameter steel rising main with associated pipes and fittings.
This is in addition to a 200kL and 150kL steel-panel reservoirs, as well as a high lift pump station that houses a 17kW centrifugal pump set with associated pipework and fittings.
Two steel agricultural storage sheds are used to store produce, as well as agricultural machinery and implements.
Gabion works were also undertaken for erosion control and restraint of historic soil erosion that would have extended into the irrigation area if left unresolved.
To ensure water demand flexibility, the two bulk water reservoirs provide storage capacity for water after abstraction and an initial lift, before distribution in-field. Part of the irrigation area can be irrigated directly from these reservoirs by gravity. Meanwhile, the water requirements for the remainder of the irrigation area can be serviced through direct delivery in-field from the high lift pump station that is located adjacent to the reservoirs. This accommodates the fluctuating water demand in-field, which is dictated by the operational demands of individual co-operative members, without adversely effecting operation nor efficiency of the water abstraction and supply.
The irrigation infrastructure is powered by solar to ensure long-term sustainability for communities, while also optimising the engineering design. Renewable energy has eliminated direct energy usage and fixed time-based costs that are associated with electrical infrastructure.
A dragline sprinkler irrigation system was selected as it is easier to manage than other available options. Furthermore, the in-field sprinkler layout, sprinkler selection and scheduling are consistent across the entire scheme. This allows for neighboring farmers and co-operatives to assist each other due to the similarity of irrigation scheduling between plots.
Meanwhile, many steps were also undertaken to ensure community understanding and contribution towards the project.
Prior to the feasibility assessment, JG Afrika consulted with the DALRRD regarding the identification and selection of available sites.
Findings and recommendations of the feasibility assessments of the drip and dragline sprinkler systems were presented by the engineering team and co-operative representatives before finalising the design.
The employment of local labour by the contractor was prioritised for activities, such as pipe trenching and laying to provide a short-term income stream for local community members. It also provided an important opportunity to develop the skills needed during the operation and maintenance of the scheme. A total of 13 temporary jobs were created during the construction phases, while 25 people were selected by the community to receive hands-on training in the correct operation and maintenance of the system on site. Meanwhile, more than 30 permanent jobs will be created in the community when production starts.
The Project Steering Committee met regularly to address construction and community-related issues. This committee included representation from the Nkungumathe co-operatives that were actively part of the consultation process required to reach resolution on issues.
Further support after completion of construction is anticipated through the department’s extension service to farmers during cultivation, including supplying their seed and fertilizer requirements.
Credit also needs to be given to the role played by the various stakeholders in ensuring a positive outcome. This includes the DALRRD for providing funding for and the opportunity to develop this milestone project. This is in addition to the community for facilitating the project and the main contractor, East Coast Irrigation, for competently executing the works, especially the creative manner it adapted solar power supply for this project.