Bacterial (E. coli) levels at the 77 National River Water Quality Network sites, 2005–2007
Bacterial (E. coli) levels at the 77 National River Water Quality Network sites, 2005–2007
| Rivers with lowest concentrations (5th percentile) (n/100mL) |
Median rivers (50th percentile) (n/100mL) |
Rivers with highest concentrations (95th percentile) (n/100mL) |
|
|---|---|---|---|
| 1989 | No E. coli data was collected at national network sites from 1989 to 2005 | ||
| 1990 | |||
| 1991 | |||
| 1992 | |||
| 1993 | |||
| 1994 | |||
| 1995 | |||
| 1996 | |||
| 1997 | |||
| 1998 | |||
| 1999 | |||
| 2000 | |||
| 2001 | |||
| 2002 | |||
| 2003 | |||
| 2004 | |||
2005 |
2.7 |
45.9 |
348.5 |
2006 |
3.6 |
53.2 |
339.5 |
2007 |
3.1 |
46.8 |
234.6 |
Notes:
(1)No E. coli data was collected at national network sites from 1989 to 2005.
(2) Hazen method used to calculate 5th and 95th percentiles.
Data source: compiled by the Ministry for the Environment using data collected by the National Institute of Water and Atmospheric Research (NIWA).
This data comes from the National River Water Quality Network which is operated by NIWA with funding from the Foundation for Research, Science and Technology.
You can access the national network data for 2007, as well as more site information, in this spreadsheet.
You can access the results of trend analysis on the national network data from 1989 to 2007 in this spreadsheet.
Return to bacteria in rivers and lakes page
Last updated: 10 August 2009
