Best Management Practices for Aquatic Vegetation Control in Stormwater Waterbodies

Auckland Council is responsible for the development and operation of a stormwater network across the region. Within this stormwater network, aquatic vegetation (including plants, unicellular and filamentous algae) can have both a positive and negative role in stormwater management and water quality treatment, as well as impact on passive and active amenity. The situations where management is needed to control aquatic vegetation are not always clear, and an inability to identify effective, feasible and economical control options may constrain management initiatives.

Thirty-five vegetation management practices (biological, chemical or physical) were evaluated, that could be potentially employed to enable better decision-making on aquatic vegetation management within stormwater systems. Each practice was considered in terms of opportunities and constraints, uncertainties, performance track record, indicative cost, and ease of implementation. Specific operation, maintenance, monitoring and reporting requirements were also outlined.

Whilst the study focussed on the Auckland environment, the outcomes should be of benefit to all practitioners managing freshwater wetlands, lakes and ponds in New Zealand.