Upper Wairarapa Valley Floodplain Management Plan

The town of Masterton, in the Upper Wairarapa Valley is bordered by three large active gravel bed rivers (Ruamahanga, Waipoua and Waingawa). The resource consents for undertaking river maintenance activities on these rivers as well as another three rivers in the Upper Wairarapa Valley are due to expire in 2015. This has presented an opportunity to review the type of activities undertaken in and around these rivers with a more holistic view of the entire floodplain that incorporates the needs and interests of the broader community.

The process being used to undertake this review is described in the Greater Wellington Regional Council (GWRC) Floodplain Management Plan (FMP) Guidelines. The process was originally developed back in the late 1980’s and was based on flood risk management international best practice concepts including the New South Wales Government’s Floodplain Management Manual and those presented in Neil Ericksen’s seminal paper “Creating Flood Disasters?”. The fundamental concepts of the process are:

• Managing the continuum of flood risk from small, frequently occurring flood events through to the largest floods a catchment can generate;
• Active participation of the community in the process of defining the flood problem and developing acceptable solutions for their river;
• Using a combination of measures to manage the continuum of flood risk, such as river management (in channel works) structural protection (stopbanks, rip-rap etc), planning controls and emergency management;
• A planning philosophy based around making sure land use is compatible with the flood risk. This philosophy includes avoiding new development in flood prone areas and keeping people away from floodwaters rather than trying to keep floodwaters away from people.

The process was successfully used in the 1990’s for developing FMPs for the Otaki, Waikanae and Hutt Rivers. The process is currently being updated to incorporate the lessons learnt from developing these FMPs along with current community expectations, resource management requirements and co-management opportunities.

This paper will describe the updated FMP process and how it is going to be applied to the floodplains surrounding Masterton.