ROTOMANUKA LAKES PROJECT
The Rotomanuka Lakes are peat lakes situated in the Waipā Region of the Waikato. They are linked hydrologically to the Rotopiko Lakes complex and drain into the Waikato River via Mystery Creek, meaning that the water quality in these lakes has a direct impact on the Waikato River.
‘A Community Catchment Restoration Action Plan for the Rotomanuka Lakes’ was a three year project, delivered with funding from the Waikato River Clean-up Trust over the period July 2012 – July 2015. It aimed to target the whole catchment, assisting the local community to work together to improve lake water quality.
Meetings were held with landowners adjacent to the lake at the beginning of the project where aspirations for the lake and ideas for restoration were discussed. Whole Farm Plans (WFP) were carried out on the three large farms in the catchment in conjunction with Headlands.
At least two successful community planting days were held. A scoping study was carried out to identify nutrient and sediment ‘hotspots’ entering the lake from inflowing streams and drains. Eighteen drains and one permanent stream were surveyed, of which all but two, flow directly into Lake Rotomanuka. Ten of the watercourses flow into the smaller South Lake and seven into North Lake. Eight sites were identified as being suitable for infiltration wetlands and four for sediment-trap treatment wetlands.
Three sedimentation ponds and infiltration wetlands were established on land adjacent to the lake as part of the project to help remove sediment and nutrients before entering the lake.
A community planting day enabled 650 native plants to be planted in around two hours. The planting in these systems were native wetland plants, which ranged from species that prefer drier areas further from waterways to those that thrive best when living directly in water.
The sediment ponds and infiltration wetlands in particular, require native wetland plants to function properly. Not only does this planting work help improve water quality but it also has broader biodiversity benefits such as providing habitat for native fish and a variety of aquatic invertebrates.
Landcare is not just about sustainability or protecting water quality, it also has a strong community ethos – encouraging people to meet other like-minded folk and share skills and knowledge.
The scoping study and the actions from the Whole Farm Plans were developed into a Community Catchment Restoration Action Plan. This action plan provides landowners and agencies working in the catchment with a prioritised list of actions that could be taken to improve the water quality over time, such as fencing drains and riparian planting.
The NZ Landcare Trust considers this document a ‘living’ document that can be amended over time, as actions are undertaken, and new technologies or knowledge become available to assist.