Notes:
(1) Statistics in the graph are derived from 95th percentile data.
(2) These results include winter sampling results, when faecal-bacteria loads are typically relatively high. This is because there is increased run-off from higher winter rainfall and bacteria tend to live longer in cooler temperatures. However, in general, recreational activities such as swimming do not take place in winter.
(2) mL = millilitres (of water).
Data source: Ministry for the Environment, in press a.
Text description of figure
Box and whisker plot comparing bacteria (E.coli) concentrations in waterways in natural, pastoral and urban catchments.
| Dominant land cover | Average 1997-2002 | ||
|---|---|---|---|
| Median | 5th | 95th | |
| Natural (122) | 209 | 7 | 5406 |
| Pasture (338) | 1179 | 105 | 13996 |
| Urban (26) | 2558 | 920 | 7714 |
Figure 10.8: Concentrations of Escherichia coli (E. coli) bacteria in rivers and streams in catchments with different land uses, 1997–2002
March 2021
© Ministry for the Environment