Bay of Plenty swimming water ranks well
Friday, 2 August 2013 11:00 a.m.
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.
Regional Council General Manager, Environmental Management Eddie Grogan said the Council monitored rivers and streams, lakes, beaches and estuaries.
"Of the rivers we monitor, three rank as ‘very poor’,” he said. “The sampling point of the Whakatane River at Landing Road bridge ranks as very poor, but at Ruatoki bridge it is ranked as ‘very good’, indicating that different sampling points provide different results.”
He said data collected over 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) was based on two measures – MAC which measured faecal indicator bacteria levels in the water and SIC, which was 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,” Mr Grogan said.
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 was a complex mix of land uses, and while water quality in the upper catchment was good, by the time the water got to the bottom of the catchment many contaminant sources could be contributing, he said.
“What is clear from our investigations is that poor results are generally linked to elevated rainfall so they are most likely influenced by runoff 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,” Mr Grogan said.
Managing contamination sources required an in-depth understanding of catchment characteristics and activities within it. Land management options such as riparian zones, ponding areas, stream crossings and land retirement, would reduce water contamination over time, he said.