How to Achieve the Key Goals

Natural Heritage

Protect and improve the health and bounty of the waterway

Explanation

Section 2.2 of the City Plan is a package of policies for the City’s waterways, which aims to maintain and improve amenity, scenic and ecological values.

Council applies values based management to all of the City’s waterways, including the Avon River/Ōtakaro, taking account of six values: landscape, ecology, recreation, heritage, culture and drainage.

For the Avon River/Ōtakaro there is a commitment to protect and improve the health and wairua (spirit) of the water, together with the riverbed and bank edges, and their suitability as habitat for many sorts of fish, birds and insects, while maintaining the river’s function as a major stormwater drainage and flood relief channel for Christchurch.

The improvement of aquatic habitats will improve mahinga kai (food gathering).

The presence of trout in an urban waterway in a large city is an unusual feature which the Council wishes to retain.

The entire corridor is a flood management area under the City Plan, which controls excavation and filling in the floodway.

Methods

Stormwater management:

Continue to use the river channel to drain stormwater from its urban catchment.

Make sure that the ability of the river corridor to carry floodwaters is kept and that features within the floodway can cope with being flooded from time to time.

Water quality:

Encourage and help Environment Canterbury to plan for and carry out measures throughout the catchment that will reduce the amount of contaminants entering the river, and to monitor their success. This should include cleaning up the sources of contaminants and first flush treatment for run-off from roads and other hard surfaces.

Teach residents about the problems caused by day-to-day activities leading to non-point source pollution of the waterway and how they can be avoided.

Water flow:

Encourage and help Environment Canterbury to work out how to make sure that the existing water depths and base flow are not reduced.

Find out if it is possible to add water at low flow periods and so to restore historic depths and flow, with a minimum flow of 1,200 litres per second.

Change the shape of the channel in some places to speed up the water flow, to increase the variety of riffles and pools, and to restore stretches of gravels that encourage fish spawning.

River bed habitat:

Check how much contamination there is in the river sediment and how it affects fish, birds and insects.

Encourage and help Environment Canterbury to introduce Integrated Catchment Management plans covering all of the water sources to find out where the sediment comes from and reduce it as much as possible.

Explore options for using certain stretches of river bed as sediment traps, from which to remove accumulated sediment at regular intervals.

Study the use of aquatic plants by fish, birds and insects, to better understand their importance to the health of the waterway and its creatures.

Remove water weed annually in places where weed growth and sediment have covered fish spawning gravels, taking care to prevent the sediment being washed downstream.

Add woody debris and emergent rocks to selected riffle areas of the river bed in order to improve their habitat value for fish, birds and insects.

Alter or remove existing weirs on the Avon/Ōtakaro mainstem and side streams to make it easier for fish to get up and down the river.

River bank habitat:

Map and monitor natural changes in the vegetation along the banks. Control the spread of exotic weed species.

Adopt design guidelines for river bank reconstruction and repair that will increase the hiding places for fish, birds and insects, and also keep areas of gently sloping banks where people can see and get down to the water.

Widen bank plantings where there is enough room, to increase the habitat for insects and to show increased recognition of the ecological values inherent in ‘landscape’.

Tributaries:

Make efforts to turn existing stormwater outfalls, land drains and piped springs into attractive features supplying clean water to the river, in celebration of their contribution to the main flow of the river.