Cannons Creek Lakes Reserve
This page describes the contents of the Ecological and Landscape Issues and Options Report prepared by Boffa Miskell Ltd, and released in June 2010.
Ecological and Landscape Issues and Options Report
Cannons Creek Lakes Reserve (CCLR) is strategically located within the Cannons Creek suburb, surrounded by four schools, community facilities and the main shopping area.
The 7.5ha valley reserve has significance to wider Porirua as an entrance to Belmont Regional Park (3500 hectares) and has ecological values. The lakes play a critical role for a large water catchment, with a detention function for flood flows estimated to be up to 41 cubic metres of water per second as a flood flow in a 100 year event.
The report was prepared to address a range of concerns including the lake's functions, quality of facilities and public use of the reserve. Funding for the report came from the Village Plan Programme budget as concerns over lakes management came up in community discussions.
Boffa Miskell Ltd and Porirua City Council have produced 100 page report reviewing existing information and obtaining new baseline data in CCLR. New information was collected on flood mitigation, stormwater treatment, sedimentation, water quality, and ecological data on fish, invertebrate fauna and restoration planting. Landscape and social issues were also investigated.
Photo above: Lake view from Warspite Avenue looking South to Belmont Regional Park Hills
While minor issues are identified, the lakes were found to be in excellent ecological health and able to successfully respond to the seasonal flooding and stormwater inputs.
With the ecological health of Cannons Creek Lakes found to be good, the report then addresses the long term strategic direction of the reserves management.
This report and the four options were discussed with stakeholders in a 2 hour workshop in February 2010. Participants included Porirua City Council, Greater Wellington Regional Council, Department of Conservation staff and representatives from Friends of Maara Roa Inc., Porirua Safer Cities Trust and Keep Porirua Beautiful.
The consensus over future development and management of CCLR was generally aligned with improving ecological values as expressed in the "Natural Vision – a forested landscape" Strategy (Option 3). The following key points were raised in support of this approach.
Natural Vision - A Forested Landscape
There was a consensus that the primary function of CCLR was its role as a flood detention basin, and above all else maintaining this main function was essential.
To preserve water quality, care was needed with new developments in the catchment and enhancements were possible. Revegetation of parts of Belmont Regional Park with the effect of reducing sediment and investigation of existing "hot spots" for contamination were identified and the Warspite culvert should be investigated to improve water attenuation.
Photo above: Flood event in Cannons Creek Lakes 2004
The new survey and sampling results show that the catchment has good to excellent water quality with high macro invertebrate diversity. Metals detected were consistent with stormwater runoff from a residential area and generally acceptable but there were slight exceptions.
Healthy populations of fish including nationally threatened species. Banded kokopu, giant kokopu and short-fin eel, together with high numbers of invertebrates were thought to be related to the absence of trout caused by the concrete channel which limits access below the lakes.
Photo above: A large native banded kokopu
Landscape and Cultural Values
CCLR is a success story and a demonstration of community revegetation in action.
Friends of Maara Roa have planted 38,000 trees since 2000, with the assistance of several local schools, Keep Porirua Beautiful, the "Adopt a Spot" programme, and the Porirua Guardians. Pasture and gorse has been transformed into native bush.
Cultural harvest of flax and watercress is occurring and further engagement with Mana Wheuna should be encouraged.
The report reveals that CCLR is less critical for local recreation, with residents having considerable choice in terms of formal recreation locally, but its significance as a regional or district-wide resource has been underestimated.
Report gives positive direction for future
The report on Cannons Creek Lakes Reserve has given a positive direction for the future. Concerns over sedimentation of lakes and water quality have been allayed. A success story of flood detention, fresh water ecology and native revegetation give a clear way forward for the reserve as part of an important regional open space network. A "Natural Vision – a forested landscape" strategy was agreed by workshop participants to be the best long term direction for the reserve.
Links to more information
Porirua City Council links: