Horizons Regional Council is responsible for managing the water quality of the region's lakes, and has been working to identify appropriate solutions for both the lake and the community.
Estimates suggest that the subset of dune lakes within the Manawatu-Whanganui region have the highest average proportions of both exotic aquatic plants (45%) and exotic fish (26%) in the country. Within the lakes of the four water management subzones, 66% of the lakes are known to contain exotic aquatic plant species (predominantly hornwort, oxygen weeds, and Potamogeton crispus) and 33% are known to contain exotic fish species.
For the dune lake catchments within the Manawatu-Whanganui region, on average only 11% of the catchment areas are in native vegetation cover, and on average 68% of the catchment has been converted to pastoral agriculture land use. Lake Horowhenua has a clean-up fund in place with a number of restoration programmes to improve the quality of the Lake through the Manawatū River Leaders’ Accord.
The Environmental management group at Horizons have been actively working with landowners to restore our coastal lakes by planting lake margins and tributaries, and fencing the Lakes and tributaries. This allows the exclusion of stock from the lakes edge and thus the possibility of runoff of sediment. Most of the region's coastal lakes have been identified as at risk from increasing nitrogen leaching from land uses in the surrounding catchment. In order to maintain the lakes' water quality, we need to reduce the amount of nitrogen leaching the lake from farmland and urban areas. There are rules in place in the One Plan around intensive land use in the coastal lakes catchments to reduce the effect of leaching on the Lakes. Leaching lakes are considered an important under the plan and there are a number of rules limiting activities such as vegetation removal, drainage, and discharge.