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City of Cape Town
City Parks Department
April 2007


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

BACKGROUND

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
Zandvlei
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

Princess Vlei
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:
SummerAutumnWinterSpring
Zandvlei, Marina2212
Princess Vlei1   
Little Princess Vlei 1  
Rutter Road 1  


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 .

Cutting limits
Distance from Shoreline propertyDepth for canoesDepths for Yachts
Zandvlei, Marina2m500mm1.4m
Princess Vlein/an/an/a
Little Princess Vlein/an/an/a
Rutter roadn/an/an/a


All shoreline property owners at Marina Da Gama are responsible for clearing a 2m weed strip along their bank edge.

Harvesting Timetable

December to mid Marchmid March to MayJune to JulyAugust to OctoberNovember
ZandvleiBoth machines at Zandvlei – control of pondweed1 Machine at ZandvleiWinter Repairs & ServicingBoth machines at Zandvlei1 Machine at Zandvlei
Princess Vlei    clearing of Hyacinth
Little Princess Vlei 1 Machine at little Princess vlei for one month clearing parrots feather   
Rutter Road relocated from princess vlei to Rutter road for one month clearing hyacinth   


Harvesting Schedule at Zandvlei

See attached Map Fig 1

Operating Times

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:
Checking of
Engine oil
Battery water
Hydraulic oil
Loose pipes and fittings
Diesel levels

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
e-mail: ricardo.delacruz@capetown.gov.za

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
e-mail: rudi.pekeur@capetown.gov.za

Talcott Persent - Rutter Road Lakeside
Transport Roads & Stormwater Department
Address: 3 Victoria Road ; Plumstead
Telephone: 021 710 8130
Fax: 021 762 5273
e-mail: talcott.persent@capetown.gov.za

Vernon Losper - Repairs & Maintenance of Machines
Specialised Technical Services
Address: 23 Oude Molen Road; Ndabeni
Telephone: 021 400 6020
Fax: 021 400 6278
e-mail: vernon.losper@capetown.gov.za

Copyright 2007. All rights reserved.