Rehabilitation of Historic Dams – Progress updateApril 23, 2021
MBB O&M – Replacement of a Ø800 mm butterfly valve on the Lower Blyde Pipeline NetworkJune 3, 2021
Making a Difference, Changing Lives.
Powered by a 15 kW electric motor with a VSD starter.
Hoedspruit Citrus Development - Van Der Merwe Boerdery
MBB was appointed by Van Der Merwe Boerdery for the turnkey design and supply of a 66 ha micro-sprinkler irrigation system for citrus in Hoedspruit, Mpumalanga. The construction of the pump stations and installation of the in-field irrigation was undertaken by Van Der Merwe Boerdery.
The citrus development consists of 33 ha Star Ruby grapefruit and 33 ha Eureka lemons, with installation over two phases. The first phase of 36 ha was completed in 2018 and the remaining 30 ha is being installed this year.
Each phase is located in separate development areas. Both phases are supplied with water from the Lower Blyde Pipeline Network (LBPN). The LBPN has been operated, maintained and administered by MBB since 2013, on behalf of the owner, Rand Merchant Bank, and supplies pressurised water to 122 farms, with approximately 8 000 ha under irrigation.
Each development area has its offtake from the network. To compensate for periods of low pressure in the lines, booster pump stations are required at each offtake to boost the pipeline pressure to the required irrigation system pressure. The pressure is only boosted when required, any residual pressure in the system is beneficially utilised. Each booster pump is powered by a 15 kW electric motor with a VSD starter. Due to the varying inlet pressures from the Blyde pipeline, pressure transducers are also installed in the pump stations to ensure the pumps operate at preset pressures.
Each of the irrigation areas is divided into twelve roughly equal irrigation blocks. Irrigation will take place over twelve shifts, meaning 1 block in each area can be irrigated at any given time per area, i.e. 2 blocks in total. The irrigation system capacity is 0,44 ℓ/s/ha. Tree spacing is 7 m x 3 m with one 40 ℓ/h micro-sprinkler per tree. This results in a possible total application of 80 ℓ/tree/day. In-field valves are grouped in clusters, at strategic positions, to make allowance for future automation using a telemetry system.