Improving the health of our waterways remains one of the biggest environmental challenges in building a more sustainable region, Greater Wellington’s annual State of Our Environment report cards show.

The report cards tell the story of what happened in the last year to the region’s river and stream health, coastal, freshwater and recreational water quality, air quality, groundwater, soil health, natural hazards and rainfall and river flows. They also highlight actions the Council is taking to manage the region’s resources more sustainably.

Monitoring of the region’s rivers and streams shows little change in water quality over the past year, with just a third of the 56 monitoring sites having excellent water quality, the same as the previous year.

These sites – including Otaki River, Wainuiomata River (upper reaches), Whakatikei River, Waiohine River (at the gorge) and Wairongomai River complied with all the guidelines we use to measure overall stream health – water clarity, oxygen, phosphorus, nitrogen and E. coli.

The 26 sites with poor or fair water quality were primarily in agricultural or urban areas, reflecting the decline in water quality once rivers and streams flow out of ranges and land cover changes from native forest to agricultural and urban uses.

“We have some pristine rivers and streams but monitoring shows that we also have many lowland agricultural and urban streams with some of the poorest water quality in the region,” Greater Wellington Regulatory Committee Chair Sally Baber says.

“We are working with groups undertaking extensive riparian planting in a number of areas, but pollutants from stormwater, dairy effluent, stock access and urban runoff continue to impact on water quality, aquatic life and streamside vegetation,” she says.

Councillor Baber says everyone in the community has a role to play in improving river and stream health.

“Businesses have a responsibility to prevent pollution, farmers need to carefully manage effluent and riparian margins, and we all need to stop putting rubbish down roadside gutters and stormwater drains.”

*Greater Wellington undertakes monitoring to observe trends and changes in environmental quality and to determine the reasons for these. Monitoring helps us evaluate the effectiveness of our environmental policies and plans, guide resource consent decision making and inform the community about our natural resources.

See www.gw.govt.nz/reportcards or the summary below.

2007/08 state of our environment report cards at a glance:

• The region had low air pollution levels. The limit for particulate matter (PM₁₀) set by the National Environmental Standard for air was exceeded on one occasion in Wainuiomata and in Tawa during winter 2007, and three times in Masterton during winter 2008.
• La Niña conditions from late spring 2007 through until autumn 2008 were responsible for one of the worst droughts on record in the Wairarapa and Hutt Valley, in terms of the number of days with a significant soil moisture deficit. Very low rainfall led to the Ruamahanga River having its lowest flow since 1985, with restrictions on water takes from rivers in place very early in the summer.
• Studies of the sediments in Wellington and Porirua harbours revealed that there is room for improvement in the health of both harbours. In Wellington Harbour, concentrations of some stormwater-derived contaminants exceed guidelines, while increased nutrient levels and sedimentation in Porirua Harbour are of concern.
• Soil quality testing on drystock/pastoral farming sites shows the soils to generally be in good condition. The primary concerns were compaction and less than ideal nutrient levels, both of which can be remedied with appropriate management.
• Despite the long dry summer, parts of the region were hit by a number of extreme rainfall events that led to localised flooding. A storm on 7-8 January caused significant flooding on the Kapiti Coast. A camping ground in Waikanae and residents from three homes next to flooded streams were evacuated. The Kapiti Coast was also hit by three tornadoes in the first half of 2008.
• The long dry summer led to greater demand for groundwater for irrigation and municipal water supply and this was reflected in record-low groundwater levels in many areas.
• Our beaches were suitable for swimming on most occasions over the summer bathing season. However, it was a different story in some of the rivers where hot, dry conditions led to extensive toxic blue-green algal growth. The Hutt River was heavily affected, with restrictions imposed on river access from January through to the end of March.

For more information please contact

Councillor Sally Baber
Chairperson, Regulatory Committee
Greater Wellington Regional Council
P 04 476 3116
M 027 476 3116
E sally.baber@xtra.co.nz

Juliet Milne
Team Leader, Environmental Science
Environment Management Division
Greater Wellington Regional Council
P 04 801 1021
E juliet.milne@gw.govt.nz

To read the original article online, click here.

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