Restoration for Lake Horowhenua given green light

Horizons Regional Council, are pleased the Environment Court has upheld the approach of the Lake Accord partners to restore water quality in Lake Horowhenua. 

This decision enables the consents for construction of a fish pass at the lake outlet to the Hokio Stream, a sediment trap on the Arawhata Stream prior to its discharge to the lake and weed harvesting with associated activities to go ahead.

The consents were granted in December 2015 following a public consenting process and appealed by Hokio Trust in January 2016 under section 120 of the Resource Management Act (RMA) 1991.

The court ruled in favour of Horizons on 22 September stating: “We are satisfied that proposed suite of activities will achieve the benefits identified in expert evidence from the Applicant and make a significant contribution to short and medium term restoration of water quality and ecological values at the lake… this will assist in the long term restoration of cultural values associated with Lake Horowhenua as a taonga of Muaupoko.”

Horizons chairman Bruce Gordon was pleased to hear the Court’s decision.

“It’s really positive to see the Environment Court has upheld and endorsed Horizons’ scientific approach.
“We’re now really looking forward to getting the activities underway and are aiming for construction to start this summer,” says Mr Gordon.

Chair of the Lake Horowhenua Trust and the Lake Accord, Matthew Sword says he is excited at the prospect of being able to finally get on with the restoration work.

“The Lake Trust has been supporting this approach with Horizons from the very beginning, this is something our owners have been waiting for.

“Now that we have the green light, we are all very eager to get going and start seeing the Lake’s improvement from these activities alongside the other work we have underway through the Lake Accord,” says Mr Sword.

Horizons natural resources and partnerships manager Dr Jon Roygard says weed harvesting will help to reduce toxins in the lake such as ammonia and cyanobacteria (blue-green algae).

“The lake weed grows rapidly through the spring and this influences the chemistry of the lake to a point where ammonia levels become toxic to fish.

“The weed naturally dies off in summer and this causes conditions that lead to the annual cyanobacteria blooms (blue-green algae blooms) that are toxic for fish and other aquatic life in the lake.

“These blooms also close the lake for recreational users. The key intervention is to harvest the weed over the spring period while it’s growing rapidly,” says Dr Roygard.

The proposed fish pass will enable fish to get from the sea into the lake, which is a vital part of their life cycle.

The sediment trap has been modelled by NIWA to remove 25 per cent of the sediment and 30 per cent of the phosphorus entering the lake annually adding to the efforts of local farmers and growers to reduce nutrient and sediment inputs into the lake.

As a part of the Accord all dairy farmers in the Lake Catchment have completed environmental farms plans and a considerable amount of work has been done with horticulture growers to reduce sediment loss.

The future of the lake is now looking positive with the resource consents being granted and upheld, these fit into part of an integrated restoration package that includes the efforts of the Freshwater Clean-Up Fund project and the Te Mana o Te Wai project that was announced in November last year.