Identifying the risk of infestation prior to development, through a comprehensive environmental assessment, will assist in identifying potential options for avoidance, future management or mitigation.  Even the best siting and design options, however, cannot control post-operational weed introductions.  A number of approaches have been applied at different stages of scheme development and operation to address pest species risks and problems.

For reservoir weed problems, pre-impoundment selective forest clearing can make reservoirs less conducive to weed growth.  Pollution control, particularly for nutrient rich streams such as sewage treatment plants or fish processing plants, can be important in some cases.  A range of techniques can be effectively employed for physical removal or containment, but with high ongoing costs.  Chemical poisoning of pest species is an option but only in extreme cases with considerable environmental caution.  In terms of within reservoir water management techniques, shorter residence times or creating better circulation through strategically placed barriers can be of assistance.  Drawdown of reservoir water levels may also be employed, although again with caution as the implications for reservoir biodiversity and shoreline stability need to be carefully considered. 

For downstream pest species issues, flushing flows can be considered to address invasion of floral species into the river channel, or concentrated removal efforts which can be accompanied by replanting of native species.  Strategically placed and purpose-designed barriers may be required for faunal pest species to restrict their range – these may include anti-jump screens, or even creating local flow velocity barriers.  Efforts to enhance conditions for native species, such as through environmental flows, can help reduce their vulnerability to pest species domination.