Mitigation and best practice options

Simple steps to minimise the effects on water quality and Mahinga kai.

The mitigation options suggested below can be linked to the effects described in the impacts pages.

Instream barriers

• Facilitate up and down stream passage for fish migration using ramps, ladders and spillways.
• Divert fish away from intake screens and outlet pipes.
• Use fish protection measures like collection buckets to get fish back into the river.
• Monitor fish migrations to provide optimal conditions during migration – eg; avoid operating at certain times of year or at extreme temperatures – above 25 degrees.

Riparian vegetation - maintaining fish habitat

• Maintain, restore and enhance riparian vegetation and wetland areas, both serve as spawning ground and shoaling habitat for Mahinga kai. Wetland areas and native planting also create refuge areas, lower water temperature and provide a food source of invertebrates for Mahinga kai species.
• Create natural meanders, low flow channels and rest areas for Mahinga kai species

Decrease sediments, nutrient and contaminant inputs

• Reduce contaminants and nutrients entering the water by planting riparian vegetation and maintaining and incorporating vegetated areas and constructed wetlands along river margins in restoration projects
• Prior to earthworks commencing, ensure erosion and sediment controls are installed - using an erosion and sediment control plan. This might include recommendations for perimeter bunds for storm water diversion,silt fencing and sediment ponds.
• An environmental assessment study should be undertaken. Habitat restoration planning should focus on enhancing and re-establishing the natural environment of the ecological community of the area.

Water flow and storage

• Regulate minimum and maximum flow levels
• Maintain natural channels and depth
• Prevent temperatures from reaching lethal or extreme levels