Marlborough rivers are in good health when compared to others around New Zealand.
Environmental Scientist Steffi Henkel told October’s Environment and Planning committee meeting that good water quality was a cornerstone of a thriving region.
“Rivers and streams hold a pivotal role in the social, cultural and economic well-being of our community,” she said.
Regular monitoring was crucial for the management of freshwater resources and there were now 56 sites around Marlborough, an increase of 22, and all these would help provide better regional coverage and accurate data.
In recent years water quality had been the focus of increased attention from central government including the introduction of a new National Policy Statement for Freshwater Management.
Ms Henkel said Council did field measurement and lab analysis of samples gathered during site visits and also sampled macroinvertebrates at 49 sites annually across the region.
Her report, which provided results for various parameters, using data from the past five years showed poor states at some sites were probably due to catchment characteristics such as mudstone geology in the Awatere River.
“In rural areas some primary causes of degraded water quality include livestock access to waterways, erosion and nitrogen leaching from fertilizer application and animal droppings,” she said. “In urban areas, contamination from sewerage due to damaged infrastructure stands as a major cause of degradation.”
Many rivers and streams in Marlborough have ongoing improvement actions in their catchments through Council’s Catchment Care programme or the Te Hoiere Project.
Analysis revealed increasing trends of nitrogen concentrations for Linkwater Stream and Mill Creek but decreasing trends for Doctors Creek and the Blenheim Springs. Decreasing trends were also observed in the Rai Catchment and Kaituna River.
E coli concentrations improved in numerous rivers and streams including the Kaituna, Cullen Creek, Doctors Creek and the Taylor River.