Regional Council worries about health of local soils

The Greater Wellington Regional Council (GWRC) says soils in Kāpiti’s vegetable growing and dairying areas are ‘not in the best of health.’

And it says the health of some streams in their lower reaches is being hit by agricultural and urban land use

But the Regional Council also says the upper reaches of rivers and streams on the Kapiti Coast are in excellent health — and many of the coast’s beach and river sites are safe for swimming nearly all the time.

First reports since 2005

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.

The reports (available at www.gw.govt.nz/ser ) include a regional overview report with key findings for air, land and water for the whole region.

And there are five summaries highlighting the health of specific ‘sub-regions’ – the Kāpiti Coast  as well as Porirua Harbour, Wellington Harbour (including the Hutt Valley and Wainuiomata),  the Wairarapa Valley and the eastern Wairarapa hills.

Fran Wilde on new ‘rule book’

Council Chair 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 reports give us a clear guide about what we need to do differently to better manage natural resources on the Kapiti Coast, including how to protect and improve water quality in rivers and streams.”

She says: “The new plan will focus on improving urban land use and infrastructure, improving rural land use, ensuring water is allocated effectively and efficiently, and managing hazards and coastal areas.”

Some of the main findings for the Kāpiti Coast sub-region are:

What’s good:

• River and stream health is generally excellent in the ranges and the Otaki River is in good health across its entire length.
• Water quality at the beaches is mostly ‘good’ for swimming – no sites are graded ‘poor’ or ‘very poor’.
• Water quality in the Otaki and Waikanae rivers is almost always suitable for swimming – but toxic algae is common in the Waikanae River when it’s warm and dry and river flows are low. Even if all other measures of water quality are good, the presence of algae means it is sometimes not safe to swim or walk your dog near the river’s edge
• Groundwater is fit for drinking in most areas on the Kapiti Coast.

What’s not good:

• A short-term monitoring programme in Raumati South during winter 2010 found poorer air quality on some nights due to fine particulate matter (PM ₁₀ ) from domestic fires
• Though some soils are healthy, most soils in vegetable growing areas have low carbon and high phosphorus levels, while some dairy soils are compacted and contain too much nitrogen
• Demand for freshwater has increased over the last few decades, largely to meet the needs of a growing population. Water levels in two of the 13 groundwater monitoring wells we monitor significantly declined between 1994 and 2011
• River and stream health is degraded in the smaller lowland streams draining intensively farmed or urban areas
• Located in an intensive farming catchment, the lower reaches of Mangaone Stream are in poor condition – they fail to meet guidelines for all six key water quality indicators. The impacts flow onto Te Horo Beach where water quality is sometimes affected by the stream
• Lake Waitawa is in a poor state – nutrients levels are too high and toxic algal blooms occur

• The Waikanae Estuary is in a moderate condition. The estuary’s sediments are quite muddy – limiting the types of organisms that can live and sediment is being deposited in the estuary at much greater than natural rates. The good news is that  levels of organic matter, heavy metals, and nutrients are all low

Measuring the health of the Region’s natural resources

Regional councils have a legal responsibility under section 35 of the Resource Management Act 1991 to monitor the state of the environment – this essentially means tracking the quality and quantity of the region’s natural resources over time. Greater Wellington does this through long-term monitoring programmes across the region focusing on:

• Air quality at 6 locations
• Soil quality (118 sites under a range of different land uses) and stability
• Rainfall (at 50 sites) and river flows/levels (at 45 sites)
• Groundwater levels (at 146 sites) and quality (at 71 sites)
• Water quality at popular river and beach recreation spots (100 sites)
• River and stream water quality and ecosystem health (at 55 sites)
• The health of selected estuaries and our two harbours