Vegetation (Floating River Vegetation) - Office of Public Works

consultation with the Foreman / Technician of the Office of Public Works and steps 9-10 are
undertaken after consultation with the staff from the Regional Fisheries Board.
Maintenance of channels is on a rotational basis generally speaking on a four to six year
cycle. Depending on the nature and quantity of deposited material, proximity to an urban setting,
probability of flooding or ecologically sensitive issues, maintenance may be of a more frequent
nature. A site visit was carried to observe arterial drainage maintenance work on the River Inny
channel C27, fifteen years since the last maintenance, to provide an enhanced aquatic environment
for fish species (Fig. 19).
4.2 Methods of aquatic weed control employed by the Office of Public Works.
Three types of maintenance regimes are employed by the Office of Works to manage
aquatic vegetation. The first is by channel maintenance, removal of deposited silt and aquatic
vegetation under the 10-step Environmental Drainage Maintenance (EDM) programme (section
4.1). Secondly, using a hydraulic excavator with a weed cutting blade attached, ideal for channels
with suitable access for large machinery and not too wide to prevent the bucket reaching the
opposite bank.
Fig. 7 Weed cutting bucket operated by a hydraulic machine (photo courstesy Office of Public Works)
Thirdly, a boat with a cutting blade attached is used for watercourses inaccessible by machinery or
channels, which are too wide for effective weed control using hydraulic machinery. The following
endeavours to explain possible biological dynamics associated with each method of aquatic
vegetation control.
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