Sites graded very good, good and fair are considered suitable for contact recreation; however good and fair sites may not be suitable at times - for example, after heavy rainfall. Sites graded poor and very poor are generally considered unsuitable for contact recreation; there is typically notification of this via signage at the site and through the media.
Prior to the beginning of the 2014/15 contact recreation season, the Land, Air, Water, Aotearoa (LAWA) website was launched to report the state of New Zealand’s environment. LAWA includes a recreational water quality component to its reporting, which details faecal indicator bacteria monitoring results collected each week by Environment Canterbury and other regional councils. Each bathing site has an overall risk classification for recreation. These are very low risk, low risk, moderate risk, and high risk/caution. Risk classes for each freshwater site are calculated using 95th percentile E. coli and enterococci values obtained over the last three years of monitoring (i.e. 2014/15 – 2016/17).
The method for calculating risk classifications on LAWA differs from that used by Environment Canterbury to calculate MACs and SFRGs. This is because Environment Canterbury follows the MfE & MoH (2003) guidelines, which stipulate using five years of microbiological monitoring data instead of three. Furthermore, LAWA risk categories do not take into consideration the influence of rainfall-affected data. Numerous sites are therefore considered as high risk on LAWA, when they may in fact be suitable for primary contact recreation under base flow conditions. In Canterbury, SFRG calculations are often adjusted for sites where high rainfall and flows are associated with elevated E. coli concentrations.
Source: Environment Canterbury Recreational Water Quality report, p30.