Semi Permanent Irrigation System| Lourens River
Semi Permanent Irrigation System Works
In brief, this project required a robust and effective irrigation system that could withstand winter flooding, dirty river water and vandalism. Additional factors, such as no access to electrical connections or formalized water supply, determined irrigation system design. As result Arid Earth Solutions engineered a semi permanent irrigation system. So, on completion of the irrigation cycle, all that remains is mainline, manifold connections and quick coupling valves. Only PVC and plastic fittings with no resale value also contribute to vandalproofing the system.
In order to meet the site challenges, a semi permanent irrigation system is designed. This system consists of six 63mm HDPE mainlines with quick coupling valves spaced at 11 meters along the seasonally flooded wet bank zone and dry bank zones.
Now, during the summer months, a portable petrol powered Davey water pump draws water directly from the river. Then, the pump connects onto one of six strategically located mainline connection manifolds. Seasonal water levels and river velocity determine the actual position of these manifolds.
Next, a set of 12 impact sprinklers installed on quick coupling keys, operate together as a zone. A manual shift of the zone occurs along the mainline at 30 minute intervals. Impact sprinklers are specified for their straight through flow characteristics, which minimizes sprinkler clogging when using dirty river water. Finally, the water pump is moved to the next mainline connection manifold.
Additional use of hand held nozzles on 30 meter draglines provide more targeted watering to areas beyond the reach of the impact sprinklers.
Irrigation Design | Irrigation Consulting | Cape Town, South Africa
The Lourens River is unique as it is the only South African river to have “Protected Natural Environment” status. It’s is about 23 kilometres long and flows from the Hottentots Holland Mountains into False Bay at Strand. Two of the objectives of this ecological restoration project was: reduce the risk of flooding and rehabilitate the riverine ecosystems.