Ashley River Berm Transition Project for Weed Control and Native Planting

2.1 Contract overview The Ashley River/Rakahuri Berm Transition Project seeks to undertake extensive targeted weed control across 24.8 ha (248,060 m2) of river berms and native enhancement planting comprised of 25,860 plants over two years. We are looking for a supplier with a proven track record of good project management and delivery of quality targeted weeding and native enhancement works of this scale.

2.1.1 Background River berms and margins are the strips of land directly beside the river, or between the river and the stopbank. Berms have an important function in flood protection by adding capacity to the main river channel by carrying water when the river is high, slowing down the flood flow to mitigate erosion risk, and absorbing excess water into the ground.

Planting trees on these berms is essential for flood resilience and protection as they provide a buffer to slow floodwaters and prevent bank erosion. Currently, most river berms in Canterbury are choked with exotic weed such as Old Man's Beard which is likely to worsen with climate change. Weed infestation is a region-wide issue that compromises the health of trees and the performance of the berm during flood.

Environment Canterbury�s (ECan) annual river maintenance involves chemical spraying and mechanical control of a range of weeds, but it is difficult to keep up. A more sustainable method of controlling weeds is to both control the target species and manipulate the environment to the disadvantage of the weed species. This ultimately reduces future weeding efforts.

The Berm Transition Project is one of Environment Canterbury�s six Climate Resilience Programme of Flood Risk Management Projects which is part-funded by the Ministry for Business, Innovation and Employment's Kanoa - Regional Economic Development & Investment Unit (Kanoa � REDIU).

The goal of this project is to transform selected areas within the braided river berms into multi-functioning areas, increasing their value, resilience and function. These areas will then provide examples to inspire future management.

It takes time to build resilience and we have a transformational opportunity with the $10m of the funding to fuel this project to protect the health of our flood protection vegetation and accelerate the regeneration of this important green asset. We will achieve this with effective, targeted invasive weed control, followed by strategic flood protection vegetation planting with under-canopy native plantings.