Waipa water services manager Martin Mould says raingardens at busy intersections in Cambridge is the first step in improving the water quality of Lake Te Koo Utu. Photo / Supplied
Waipa water services manager Martin Mould says raingardens at busy intersections in Cambridge is the first step in improving the water quality of Lake Te Koo Utu. Photo / Supplied
Waipā District Council's quest to filter stormwater from the streets of Cambridge to make improvements in the water quality of Lake Te Koo Utu is starting to flow.
Construction of the first of a three-step process to build several rain gardens to treat stormwater runoff before it enters the lake is programmed to start this month and is expected to finish in June.
Water services manager Martin Mould said the town's busy intersections such as Victoria roundabout, were the focal areas in the early stages.
"This is the first step in improving the water quality of Lake Te Koo Utu," he said.
"At this stage, we have targeted the busiest roads and intersections for maximum effect in treating contaminants from stormwater runoff before they enter into the lake."
A rain garden looks like any other traditional garden on the surface, but under the soil, there are layers of various media and plant roots that act as natural filters for surface runoff.
Mould said the gardens help provide a place for rainwater to soak into the ground allowing a natural filtration process to remove contaminants such as oil, petrol, zinc and rubber from cars which are collected in rainwater and eventually made their way into the lake.
Rain gardens can play an important role in protecting habitat and help with climate resiliency, Mould said.
"The specifically designed garden is set into the ground to remove sediment and contaminants, such as hydrocarbons, from the road's surface at first flush, which prevents those from entering Lake Te Koo Utu and will help improve the water quality.
"Lake Te Koo Utu is home to many fauna and flora, improving the water quality here will improve the ecosystem for our eels and native invertebrates to thrive."
Installing rain gardens was one of the council's approaches to improving water quality through the Lake Te Koo Utu concept plan, adopted in 2021. The [cost] to fund design and installation was allocated through the 2021-31 Long-Term Plan.
Design and construction of stages two and three, aimed at targeting high use and other collector roads will proceed as funding allows, Mould said.
More information about the rain gardens project can be found at https://bit.ly/366GLAp and other water quality improvements projects for Lake Te Koo Utu can be found at https://bit.ly/35PFYnI.
Construction begins to reinstate the lake level of Kimihia
Meanwhile, work is under way at Lake Kimihia, just north of Huntly (Rahui-Pōkeka), to reinstate the lake level and deliver on environmental and cultural improvements.
Lake Kimihia was reduced from 318ha to 44ha because of historic open cast coal mining and has been completely drying out over recent summers, leading to the death of tuna (eels) and significant habitat loss.
Waikato Regional Council says the lake will be reinstated to the level that was set when a weir was constructed in 1990, but which has since failed. MS Civil Construction has started building a bund and weir and installation of two culverts. The weir incorporates a pest fish barrier, which will reduce the movement of pest fish into the lake.
Lake Kimihia was reduced from 318ha to 44ha because of historic open cast coal mining and has been completely drying out over recent summers. Photo / Waikato Regional Council
The project also supports the restoration of 9ha of wetland on adjoining farms, with 8km of fencing and the planting of 33,000 native plants.
The lake is a significant natural area of very high importance and value to Waikato-Tainui hapū, particularly Ngāti Naho, Ngāti Mahuta and Ngāti Whāwhākia.
A cultural enhancement plan has been developed to identify cultural aspirations for the site, which will inform restoration activities.
Iwi and the local community have advocated strongly for the lake, the values it holds and the need for intervention for some years.
Integrated Catchment Committee chairman (north) Stu Husband said it was fantastic to see this work being realised.
"The lake has been a concern to iwi and the community for some time. Basically, people really wanted to restore that feeling of pride in their waterway and this is a great step towards achieving that. The design of the bund and weir also took into account flooding concerns within the catchment, so there are multiple benefits to the project."
This project has been made a reality through a collaborative partnership between the council, Waikato-Tainui, Wahi Whanui, the Department of Conservation and local landowners, and $1.556 million in funding by the Government (as part of its economic response to Covid-19) and Waikato River Authority.
Waikato Regional Council received $740,000 from the Ministry for the Environment's Public Waterways and Ecosystems Restoration Fund as part of Jobs for Nature funding; $640,000 in IRG climate resilience funding Kānoa – Regional Economic Development and Investment Unit; and $176,000 from the Waikato River Authority.
This project aims to see Lake Kimihia become an open waterbody year-round and enhance surrounding wetlands, providing habitat for native fish species and waterfowl.
