City of Cape Town|
City Parks Department
Annual Plan of Operation for the mechanical harvesting of aquatic weed in Zandvlei, Marina canals and Princess vlei.
The purpose of this plan is to provide guidelines for the efficient and effective harvesting of aquatic weed in local vlei’s and canals.
This plan was compiled in accordance with recommendations made by Dr Bill Harding on the management and conservation of Sago Pondweed(Potamogetan pectinatus) in Zandvlei
Harvesting EquipmentTwo aquatic weedharvesters are currently based at Marina da Gama and are largely used in this area to control the growth of Pondweed . These machines are approximately 25 years old and have been built locally by the City’s Mechanical division in the early 80’s They are the prototype of Industrial Machines utilised throughout the world and have the capacity to remove many of the common invasive aquatic weed.
Mechanical HarvestingMechanical harvesting provides a relatively cost effective approach to the removal of unwanted aquatic plants with minimum risk to human health and safety. It is the only effective mean of controlling pondweed which is crucial in the maintenance of good water quality in Zandvlei and the marina canals.
Areas requiring weed harvesting
This area is known for fishing, yachting ,canoeing, boardsailing and swimmining.
An estimated 35ha is needed to be kept clear for the above recreational activities
Weed to be harvested: Sago Pondweed(Potamogetan pec.) and Algae
Used mainly for fishing
The area requiring harvesting is approximately 4-5ha .
Weed to be harvested : Water hyacinth
Little Princess Vlei
Used for fishing and canoeing
Area requiring harvesting is approximately 3ha
Weed to be harvested : mainly Parrots feather
Rutter Road area Lakeside
Keyser River inlet
Area to be harvested is approximately 2 ha
Weed to be harvested : Water hyacinth>
HARVESTING AND MANAGEMENT GUIDELINES
Frequency of Harvesting The following is the least number of seasonal cuts required per area:
Time of harvesting
Pondweed in Zandvlei attains its seasonal peak between October to April. Thereafter growth decline during the winter months.
Water hyacinth and parrots feather has an active growth period during warm seasons but a once off removal of the plant would suffice in keeping the water clear for at least 10-12 months .
All shoreline property owners at Marina Da Gama are responsible for clearing a 2m weed strip along their bank edge.
Harvesting Schedule at Zandvlei
See attached Map Fig 1
The machines are required to be in operation for a minimum period of 6hours between the hours of 08:30 to 15:00
Limitation to operation
These machines cannot operate in rainy weather and strong winds. Breakages on the machines could lead to long hours of downtime due to parts not being readily available
Springtide – Zandvlei only
The opening of the river mouth at springtide causes the water level in canals to drop thus creating an impression at times that urgent harvesting is required.
Daily maintenance on machines
The Operator is required to perform the following daily checks and tasks on the Machine:
Loose pipes and fittings
Clearing of weed from cutters and motors
Updating logbook and daily worksheet
Repairs to machines
The responsible depot(Muizenberg Parks) reports all breakages to Technical Support Services in Ndabeni who arranges for a quotation on repairs and the appointment of a suitable vendor.
Operators and substitute
Each machine has a dedicated operator who was trained in operating these machines
H620 – operated by W. Petersen
H621 - Operated by E. Benjamin
In the event of an operator not being available a substitute exist in Mr J Swail who is also trained to operated the machine
Relocation of Machines
This is a costly and complex exercise and there is a risk of causing damage to external pipes as the machine was not designed for this purpose
Contact Detail of responsible Officials
Ricardo De La Cruz - Zandvlei and Marina Canals
Muizenberg City Parks Department
Address: Off Coniston Avenue; Steenberg
Telephone: 021 701 1233/4
Fax: 021 701 9983
Rudy Pekeur - Princess vlei and Little Princess vlei
Heathfield City Parks Department
Address: Off Dalbour Road ; Heathfield
Telephone: 021 705 3762
Fax: 021 705 0329
Talcott Persent - Rutter Road Lakeside
Transport Roads & Stormwater Department
Address: 3 Victoria Road ; Plumstead
Telephone: 021 710 8130
Fax: 021 762 5273
Vernon Losper - Repairs & Maintenance of Machines
Specialised Technical Services
Address: 23 Oude Molen Road; Ndabeni
Telephone: 021 400 6020
Fax: 021 400 6278
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