Morphological model of the lower Waikato River

In 2010 B&M completed a morphological model of the lower Waikato River for Winstone Aggregates Ltd, simulating both water flows and sediment transport. Using the Mike11 morphological modelling software, the model extended from Hamilton to Port Waikato, including tributary the Waipa River from Whatawhata to Ngaruawahia. The hydraulic model was first calibrated to recorded flows and levels. Channel cross section surveys from 1988, 1998 and 2007 were used to calculate the changes in channel volume over time. This information together with sediment sampling data was used to calibrate the sediment transport part of the model. Predictive simulations extending 50 years forward were then run to assess the long term evolution of the channel and the effect of proposed sediment extraction on bed levels.

A view of the bridge over the Waipa at Whatawhata during bed sediment sampling.