Report: TR05/04

Author: Edmund Brown

Abstract

The purpose of this report is to provide quick reference charts of estimated travel times along major Waikato rivers in response to emergency situations such as hazardous spillages.

The term 'travel time' is simply the calculated time it takes for a body of water to travel between two points. The rivers and streams analysed are those most at risk of contamination by hazardous substances due to their proximity to major roads and railways.

The travel times are based on measurements of river and stream length, discharge and mean velocity. The travel times for each of the rivers and streams analysed are presented for two reference flows, the 15th and 85th percentile flows. The 15th percentile flow represents high flow conditions which are equalled or exceeded 15 percent of the time and the 85th percentile flow represents low flow conditions which are equalled or exceeded 85 percent of the time.

The flow velocities of the various flow gauging sites in each catchment are referenced to one location, the reference site. This negates the need for the user of the tables to have flow measurements for all the sites.

Note: The travel times given are only approximate and provide a first approximation for emergency instance planning purposes. However, due to the number of assumptions and limitations used in the calculations there may be considerable variation between what is reported here and what actually occurs for each water body.

Hydraulic Travel Times of Major Waikato Rivers [PDF, 784 KB]