Wellington region's air, land and water - state and trends
Our region’s air is clean in most places, we’ve plenty of good soils, and nearly all the beaches we monitor are safe to swim on most occasions.
But there’s room for improvement. Water quality in our rivers, streams and lakes is a mixed bag, and the amount of water taken for agriculture and for public supply continues to grow meaning there’s less water available in some waterways and groundwater aquifers.
Greater Wellington has just released a series of reports documenting the health of our air, land, freshwater and coastal resources – the most comprehensive analysis of the state of our natural environment since 2005.
“We’re lucky to continue to have a region that is in pretty good shape when compared with other parts of the country. Nevertheless we definitely have some localised pressures that we need to respond to,” Greater Wellington Regional Council Chair Fran Wilde says.
“The poor health of small streams in urban and intensively farmed areas is cause for concern, as is the health of Lake Wairarapa and parts of Porirua Harbour. The current state of these water bodies impacts on the health of the aquatic animals that live there, and on people’s ability to use them for recreation and food gathering.
“We’ve already started to work with communities and with local councils to respond to environmental issues that these reports identify.
“We’re working alongside Porirua City Council, Wellington City Council and Ngati Toa to implement the new Porirua Harbour and Catchment Strategy and Action Plan that aims to reduce the amount of sediment and pollution going into the Harbour, and restore the Harbour’s ecology.”
Greater Wellington is proposing to spend $90,000 more each year on science, monitoring and ecological restoration in and around the Porirua Harbour.
The Council also received $1 million from the Government’s Fresh Start for Fresh Water Clean-Up Fund to restore Lake Wairarapa. A leadership group involving local councils, farmers, environmental groups, iwi and community members will use the fund to improve water quality, biodiversity and eradicate pest plants.
“Through the Wairarapa Water Use Project we’re looking at the potential to store water flowing off the Tararua Range to provide for a range of uses and take the pressure off highly allocated rivers, streams and aquifers in the Wairarapa Valley.
“And with the Carterton District Council, Rangitane O Wairarapa and Kahungunu ki Wairarapa, farmers and community members we’re working to find solutions to improve the health of the highly degraded Mangatarere Stream.
Fran Wilde says the report findings are feeding into the development of a new, integrated regional plan – the ‘rule book’ for ensuring our region’s natural resources are sustainably managed. The current regional plans are now more than 10 years old.
“The reports help inform where the current plans are working and what we need to do differently in the new regional plan,” she said.
“As with these reports we’re taking a catchment-based approach to developing the new plan. We’re engaging with communities in different parts of our region both about how we can improve the rules in the plan and use collaborative approaches to enhance environmental management.
“The new plan will focus on improving urban land use and infrastructure, improving rural land use, ensuring water is allocated effectively and efficiently, looking after coastal areas and managing natural hazards.
Fran Wilde said local councils also had a role to play in improving and protecting the environment, through investing in and maintaining modern sewerage and stormwater infrastructure.
“Communities, farmers and individuals can also play their part by keeping agricultural and urban pollutants out of our waterways and coastal areas.”
About the air, land and water summary reports
The reports (available at www.gw.govt.nz/ser) include a regional overview report with key findings from our monitoring of air, land and water resources across the whole region. There are also five summaries – Kapiti Coast, Porirua Harbour, Wellington Harbour (including the Hutt Valley), Wairarapa Valley and Eastern Wairarapa hills. These highlight what’s happening with air, land and water in different parts of the region. Each summary also includes a section “what you can do to help”.
These summary reports are based on eight detailed technical reports which give the full picture of the health of the Wellington region’s air, land, fresh water and coast.
What’s good
- Air quality is good most of the time. PM10 (fine particles in smoke) is the only pollutant that fails to meet the national standard – and only in the Wairarapa Valley
- At most sites we sampled, soils are in very good or good condition for their land use
- Water quality at 31 of the 55 river and stream sites we monitor is rated excellent or good. These sites are mostly on larger rivers flowing from the Tararua/ Rimutaka ranges
- 20 of 23 popular river spots met the national guideline for safe swimming on 85% of sampling occasions over the five summers we looked at. Most beach sites rated even better – a few sites like Scorching Bay in Wellington city were safe 100% of the time
- Aquatic vegetation surveys in 2011 rated the ecological condition of the Parangarahu Lakes (Lakes Kohangatera and Kohangapiripiri) and Lake Pounui in South Wairarapa as ‘high’ or ‘excellent’
- Castlepoint Beach, the only sandy beach we monitor for ecological condition, is in good health
- Our Drinking Water Quality Index classified 75% of the 71 groundwater aquifer sites as being ‘good’ or ‘excellent’ for drinking
What’s not so good
- PM10 levels occasionally fail to meet the national standard in sheltered areas of the Wairarapa Valley during cold, clear and still conditions when people use fires for home heating
- Soil health is not so good in vegetable growing areas due to low carbon and high phosphorus levels while dairy soils are compacted and contain too much nitrogen
- Demand for water from aquifers, rivers and streams is higher than ever. Allocation doubled between 1990 and 2010, mainly for more farmland irrigation and town supply. Many rivers and streams, particularly in the Wairarapa, are now fully allocated
- Water levels in half of the 29 aquifer monitoring wells assessed in the Wairarapa Valley declined significantly between 1994 and 2011 and water levels in some don’t appear to fully recover in winter
- Water quality and ecological health are degraded in many small urban and agricultural streams while some river sites are unsuitable for swimming because of faecal contamination
- Lake Wairarapa and neighbouring Lake Onoke and Lake Waitawa (on the Kāpiti Coast) have poor water quality
- Porirua Harbour’s ability to support life, and its overall ecological health, is beginning to be affected by the build up of sediment, nutrients and contaminants carried in the stormwater. Stormwater contaminants are also present on the bed of Wellington Harbour
- The estuaries we monitor are all in a moderate or ‘fair’ condition but in most, the rate of sedimentation is higher than ideal
- Owhiro Bay on Wellington’s south coast, Robinson Bay (Eastbourne) and beaches around Porirua (Porirua Harbour, South Beach at Plimmerton and Titahi Bay) are sometimes not safe to swim. These beaches are graded ‘poor’ at least in part due to faecal contamination from sewer and stormwater infrastructure