The focus of the One Plan is four keystone environmental issues: surface water quality degradation, increasing water demand, unsustainable hill country land use and threatened indigenous biodiversity. These issues were identified during public consultation and confirmed by research of the Regional Council’s science team.

By focusing on these Big Four issues, substantial progress can be made at an affordable level of expenditure for the Region. The Big Four have significant interconnection and it is expected that work on one issue will also benefit progress on one or more of the other issues. Notwithstanding the focus on these Big Four issues, other resource management issues are also important and are dealt with in the One Plan.

Issue 1: Surface Water Quality Degradation

The Problem:
Run-off of nutrients, sediment and bacteria from farms is now the single largest threat to water quality in the Region. In some water bodies it is risky to swim or gather food, and aquatic life is being damaged. Priority catchments for water quality enhancement include those listed in Table 14.1 in Part II of the Plan which sets out the specified Water Management Zones* and Sub-zones* (priority catchments) where management of intensive farming land use activities will be specifically controlled. These are: Mangapapa River, Mangatainoka River, Upper Manawatū River above Hopelands, Waikawa Stream, Manawatū River above Gorge, other south-west catchments (Papaitonga), and other coastal lakes (Northern Manawatū).

An Example: The Manawatū River In the Manawatū River nutrient enrichment is one of the most critical problems. Recent research found that on an annual basis, more than 80% of the nitrogen and 50% of the dissolved reactive phosphorus found in the Manawatū River at Hopelands is coming from run-off from agricultural land. This pattern is repeated in many other catchments.

Excessive nutrients cause nuisance algae growth on the river bed, particularly during summertime low flows.

Proposed Approach:
Set water quality targets for ecosystem, recreational, cultural and water-use values identified for catchment Water Management Sub-zones*. Identify Water Management Sub-zones* most affected by nutrient enrichment and/or bacterial contamination. Use a mixture of persuasion, advice and rules to manage agricultural run-off in these Water Management Sub-zones*.

Look For: Objectives, policies and methods that address this keystone issue in Chapter 5 and rules in Chapter 14.

Issue 2: Increasing Water Demand

The Problem:
The amount of water used from ground and surface water resources increases each year. At certain times of the year public water supply* and irrigation demand exceed what some water bodies in the Region can supply.

An Example: The Upper Manawatū River
Across the Region, total consented abstraction volumes have more than doubled since 1997 (Horizons Regional Council, 2005, SOE Report). In the upper Manawatū River and its tributaries, the current demand for water is close to three times that of 1997. Most of this increased demand is for agricultural irrigation which, in 2005, was four times the 1997 levels and took up over 80% of the water allocated.

Proposed Approach: The Regional Council has set minimum environmental flows and defined core allocation volumes for Water Management Sub-zones* under pressure from surface takes. These will be used to manage and allocate water. The Regional Council is also working with water users to encourage water-use efficiency and accurately define abstraction rates using telemetered water meters.

Look For:
Objectives, policies and methods that address this keystone issue in Chapter 5 and rules in Chapter 16.

Issue 3: Unsustainable Hill Country Land Use

The Problem:
Unsustainable pasture-based farming practices in the Region’s steeper hill country damage soil structure and accelerate erosion causing muddy rivers, increasing river siltation downstream and reducing the protection level of flood control schemes.

An Example: February 2004 Storm
The Region has 300,000 hectares of hill country land at risk of moderate to severe erosion. In the severe storm events of February 2004, huge quantities of soil poured off the hills of the middle catchments west of the Ruahine Ranges and into some water bodies such as the Whanganui, Rangitīkei, Oroua and Pohangina Rivers. Many areas of the Region were badly affected, with severe hillside scarring and valley in-filling often reported in national media coverage.

Proposed Approach:
Implementation of a Sustainable Land Use Initiative (SLUI) on hill country land that is subject to an elevated risk of accelerated erosion* within the Region, in combination with rules where appropriate. The initiative is underpinned by the development of voluntary management plans. These voluntary plans provide paddock-scale best land management advice while optimising economic return to the landowner. The first voluntary management plan was piloted on a farm in the Pohangina Valley in 2005 and the programme is currently being rolled out in priority areas.

The SLUI has the additional benefit of assisting the Region to adapt to the effects of climate change.

Look For:
Objectives, policies and methods that address this keystone issue in Chapter 4 and rules in Chapter 13.

Issue 4: Threatened Indigenous Biological Diversity

The Problem: Due to more than a century of landscape modification, the Region has lost much of its indigenous habitat. Habitat remnants continue to be threatened by land development and by pest plants and pest animals.

An Example: Vanishing Wetland Habitats
The Manawatū Plains were once covered by a mosaic of wetland habitats. Large scale drainage has reduced this wetland habitat to about 3% of its former area and, although drainage has mostly stopped, the few remaining wetland habitats are still vulnerable.

Proposed Approach:
The Regional Council will be the lead agency for indigenous biodiversity1 management for the Region by controlling activities in rare habitats, threatened habitats and at-risk habitats, and working with landowners to protect and enhance these habitats.

The Regional Council has identified the Region’s top 100 wetland habitats and is encouraging their owners through advice and financial incentives to actively manage these habitats. The objective of the programme is to have all 100 wetlands under active management within 10 years.

Look For:
Objectives, policies and methods that address this keystone issue in Chapter 6 and rules in Chapter 13.

1    "Biodiversity" may be used as an alternative to "biological diversity".