The Client: Friends of Lake Hayes, Mana Tāhuna Charitable Trust

The Challenge: Wai Whakaata Lake Hayes has suffered from a legacy of high nutrient and sediment loads in the catchment, leading to poor water quality and algal blooms. Nutrient loss is diffuse throughout the catchment; and has been exacerbated by land use change, removal of native vegetation, stock access to waterways, draining of wetlands, channelisation of water courses and streambank erosion. e3Scientific were firstly approached by Friends of Lake Hayes to create a vision for the works that could be completed throughout the catchment. As the project gained momentum and funding, e3Scientific has worked on the project management team to provide technical and consenting support to Mana Tāhuna Charitable Trust to implement the vision.

Process and Solutions: e3Scientific successfully obtained a global consent to complete bank battering, willow removal and sediment traps within the Lake Hayes Catchment and have supported Mana Tāhuna by developing designs and Site Environmental Management Plans for sediment traps in the catchment. For the regionally significant wetland at the north end of Lake Hayes, e3Scientific developed a Wetland Restoration Plan in accordance with the NES for Freshwater Management.

Project Outcome: Bank battering, willow removal and replanting has been completed across many eroded sections of Mill Creek. Two in-line sediment traps have been completed and are almost full of sediment, after less than one year of operation, with one further off-line sediment trap planned for this year. Wetland restoration is in process at the north end of Lake Hayes, with thousands of native plants growing where once willows choked the waterways. Our community are already noticing the impact of these combined interventions.

Client testimonial: “The knowledge and professionalism of e3 Scientific is outstanding. We felt confident they understood and delivered on our vision of making Te Waiwhakaata Lake Hayes swimmable again. Their willingness to support our mātauranga with scientific knowledge strengthens the depth of knowledge and cooperation for our team, our community and te Taiao.”