Supporting informed water supply decisions for Wellington
NIWA is helping the Greater Wellington Regional Council with tools to manage the current and future water supply for the Wellington urban area, made up of Porirua, Hutt, Upper Hutt, and Wellington Cities.
By using NIWA's TopNet hydrological model to produce long series of estimated river flows at different locations throughout Greater Wellington's water supply catchments, the Council can now investigate options for additional water storage facilities. With the greatly extended range of new river flows, water supply estimates can be produced for possible future abstraction points as well as for existing abstraction points.
This information is then used to drive the Council's Sustainable Yield Model (SYM). The SYM allows minimum flow rules to be applied, and takes account of changing water demand and limitations caused by pipe capacities and pumping rates.
We have just completed two further projects with Greater Wellington. The first is a software tool to allow the Council to use their SYM to investigate the effectiveness of demand management options when a drought is forecast (If we put on a hosing ban, what are the chances that we will run out of water this summer?). The other extends the Council's options for including groundwater supplies into the SYM so that they can examine different options for jointly managing surface and groundwater.