Author: Edmund Brown
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
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|2 How to use the travel time tables||1|
|3 Calculation of the travel times||3|
|3.1.1 Discharge and velocity estimates||4|
|3.1.2 Tidal influence||4|
|3.1.3 Transport mechanisms and chemistry||4|
|3.1.4 Storage lakes||4|
|4 Waikato River||6|
|4.3 Western Bays of Lake Taupo||12|
|5 Waipa Catchment||13|
|5.1 Mangapiko River to Waikato Heads||14|
|5.2 Punui River to Waikato Heads||16|
|5.3 Mangaoronga Stream to Waikato Heads||18|
|5.4 Mangapu Stream to Waikato Heads (includes Waipa River downstream of Otorohanga)||20|
|5.5 Mangaokewa Stream to Waikato Heads (includes Waipa River downstream of Otorohanga)||22|
|6 Waihou River||24|
|6.1 Kuhatahi Stream to Waihou River Mouth||26|
|6.2 Purere Stream to Waihou River Mouth||27|
|6.3 Oraka Stream to Waihou River Mouth||28|
|6.4 Rapurapa and Waiomou Streams to Waihou River Mouth||29|
|6.5 Mangawhero Stream to Waihou River Mouth||30|
|6.6 Ohinemuri River to Waihou River Mouth||31|
|7 Piako River||32|
|7.1 Morrinsville to Piako River Mouth||33|
|7.2 Waitoa River to Piako River Mouth||34|
|8 Awakino River||36|
|8.1 Awakino River||37|
|9 Mokau River||38|
|9.1 Herekawe Stream to Mokau River Mouth||39|
|9.2 Pangaki and Mangaotaki Streams to Mokau River Mouth||40|