Bay of Plenty's rivers, streams, lakes and coasts have generally good water quality for swimming.

Bay of Plenty Regional Council monitoring shows that of the 80 sites the council monitors, 49 are rated good to very good, 13 are rated fair and 17 are rated as poor to very poor.

Swimming water in the Bay of Plenty is making the grade.

BOPRC environment management general manager Eddie Grogan says of the rivers monitored, three rank as ‘very poor'.

'The sampling point of the Whakatane River at Landing Rd bridge ranks as very poor, but at Ruatoki bridge it is ranked as ‘very good', indicating that different sampling points provide different results.”

Eddie says data collected during a five-year period is used to calculate the ranking of a river, stream or lake; and bad weather during the bathing season can influence the result.

The ‘suitability for recreation grade' (SFRG) is based on two measures – MAC which measures faecal indicator bacteria levels in the water and SIC, which is a catchment-based risk assessment.

'Some sites will always be rated poor or very poor due to the combination of land uses in the catchment.

'Where there is a sewerage treatment and disposal plant in the catchment it can only ever rank as ‘poor', regardless of whether the actual sampling results are poor or not.”

When a poor result is identified, regional council staff evaluate potential influences and look for recurring patterns and try to eliminate likely sources.

The Whakatane River catchment is a complex mix of land uses, and while water quality in the upper catchment is good, by the time the water got to the bottom of the catchment many contaminant sources could be contributing, says Eddie.

'What is clear from our investigations is that poor results are generally linked to elevated rainfall, so they are most likely influenced by run-off from rural land and urban storm water. Sometimes, these have occurred in dry weather, but we have not found a source.

'Freshwater quality is a major issue for the regional council; and last year we established a Water Programme of Action after the Ten Year Plan 2012-2022 was approved. This plan includes activities and projects about how we manage the region's freshwater resources.”