(Section 18 of the RPS)

Water quantity refers to the natural flows and levels of water in aquifers, springs, streams, rivers, lakes and wetlands and the tidal movement of coastal waters. Reduction in water quantity can directly influence water quality and therefore integrated management of both water quality and water quantity is required at a catchment level.

The landforms and ecology of Northland have adapted to the natural water quantities over time. Human activity has led to major changes in land use, and these have resulted in significant changes in water quantities in many of the region's rivers and wetlands, and locally in groundwater, lakes and some estuarine areas.

Construction of roads across hillsides and floodplains, stop banks and drains on floodplains, and drains or land development on sloping land can disrupt or alter the natural drainage pattern by damming, diverting and discharging runoff. These activities are controlled to prevent or minimise the nuisance or detrimental effect or damage to property. A significant number of streams and rivers are already heavily used for water supplies (generally for reasonable stock and drinking water). The level of use means that any future water demand will require the use of alternative sources, particularly storage of water in dams or reservoirs.

Anticipated Outcomes

· Protection of important freshwater habitats, particularly natural wetlands from reductions in surface water and ground water levels.

· Preservation of natural character, intrinsic, ecosystem, and amenity values of natural water bodies to the extent that these depend on water levels and flows.

· Protection of the values of water bodies held by Tangata Whenua.

· Sustainable and efficient use of the water resources of Northland.

· Increased awareness of water conservation and the greater implementation of water conservation practices.

· Minimisation of actual and potential damage to property from damming, diversion and discharge of run-off.

Policy Mix

The objectives for the Water Quantity and Flows section are:

· the maintenance of the flows and levels in significant streams, rivers, lakes and wetlands;

· the maintenance of water flows and levels in natural water bodies;

· the sustainable use of groundwater resources;

· the efficient use and conservation of water resources;

· to protect property and other values from adverse effects of water diversion.

The policy approach for the protection of water bodies with high ecological, cultural or scenic values (Policy 18.4 (a)) is to restrict and prohibit uses which would have adverse effects on these values. A precursor to this is to identify and document those water bodies of high value.

The policy approach for the maintenance of river and stream flows (Policy 18.4 (b)) is firstly to identify maintenance flow requirements, and whilst this is occurring to adopt a conservative but practical approach.

The sustainable use of groundwater and lake water resources (Policy 18.4 (c)) is approached by specifically targeting the effects on surface waters, including wetlands and the avoidance of saline intrusion and by considering rivers, streams, groundwater and lake water as taonga, where appropriately identified. The effects to be avoided are considered to be unsustainable and therefore those activities that lead to those effects should be prohibited.

The efficient use and conservation of water (Policy 18.4 (d)) is approached through a mix of regulatory and advocacy methods. The policy approach for structures in rivers and streams and for the damming and diverting of water is a solely regulatory approach.

The Water Quantity and Flows section contains 28 individual methods of implementation that flow from the policy direction discussed above.

What's the current state?

Annual rainfall ranges from 900mm in low-lying coastal areas to over 2900mm at higher altitudes. Flows vary greatly between catchments, which can be largely attributed to rainfall patterns, catchment size and catchment geology. In Northland, catchment geology has typically resulted in an absence of significant rivers, which means we do not have rivers that can maintain a significant base flow during drought conditions.

Changing land use from traditional farming to horticulture, market gardening and increasingly towards intensive subdivision and development, together with an increase in tourism has resulted in increasing pressure on many of Northland's aquifers. These changes in land use also have the potential to alter the recharge rates of underlying aquifers.

Northland's many coastal aquifers are at risk from saltwater intrusion due to reduced recharge from increasing impermeable surfaces and reticulation of stormwater, and increasing extraction which is resulting in the withdrawal of freshwater being too great and this is allowing salt water to ingress into the aquifer. Additionally, a number of the aquifers are at risk from contamination from poorly maintained effluent disposal systems.

NRC currently has no policy on total allocation (limit) for water resources. Each consent is assessed on a case-by-case basis, including imposing conditions to require design minimum flows to be maintained. These applications, assessed on an individual basis do not address the cumulative impact of water extraction. Many sub-catchments in central and southern areas of Northland, particularly in the Wairua Catchment, are over-allocated.

Agriculture is the greatest user of water in Northland, however this has decreased since 2002, from approximately 52% to 38%. This water is mainly used for irrigation. Horticulture accounts for 34% of the total volume of water allocated. Most of the horticulture activities take place on the fertile volcanic soils near Maungatapere, Maungakaramea, Kerikeri, Aupouri Peninsula and on the sandy clay loam soils on the west coast, near Dargaville.

Water supplies to towns and cities account for 23% of the total allocation of water for Northland. The district councils are the main suppliers of water, taking from streams, rivers, springs and dams. As increased development occurs near urban and coastal areas, demand for water supply in these areas will increase and additional sources of water will have to be found or development will have to be self-sufficient i.e. use roof water.

What has worked well in this section?

The provisions of the Regional Water and Soil Plan for Northland (RWSP) accurately reflect the policies of the RPS.

The NRC has been able to identify and set allocation limits for individual irrigation consents based on mean annual low flow.

What has not worked in this section?

A comprehensive record of high value water bodies is required to supplement the existing record of outstanding water bodies. Water allocation and the transfer of water permits is not currently managed within the RWSP as no sustainable limits have been set for water resources.

Springs are often waahi tapu and this is not effectively recognised and addressed within this section. Similarly the identification and consideration of waters that have taonga status or cultural heritage values has not been effectively achieved.

Water resources need to be managed on a more holistic basis with particular attention paid to the interrelationship between surface and groundwater resources. The actual and potential impacts of land use/land use changes on hydrology also require attention.

General comments on this section:

Northland has very finite water resources and is quite unique in that it has small streams and catchments. Concern has been expressed at the balance between stock needs, commercial and agricultural use competing with reasonable domestic needs and district council's requirements for public supply. Managing competing needs requires a water allocation regime based on a consistent and robust methodology.

Is this section Efficient and Effective?

In general, the provisions required by the RPS are included in regional plans but are not considered to adequately cover water quantity issues, particularly in relation to land use impacts, climate change, allocation limits and minimum flows. There are problems determining what is ‘reasonable' domestic and stock drinking water and the effects of water takes for dams need to be addressed.

Water allocation on an individual stream/catchment basis is a significant challenge for the region that urgently needs to be addressed.

Overall this section is not effective and efficient due to a lack of basic environmental information.

Emerging Issues for this section?

Water allocation limits and certainty of public supply are significant issues facing Northland. Lifestyle development is increasing pressure on water resources and the resource may not be able to meet this demand in places. Applications for subdivision and development should be required to identify their available water supply at the time of applying for consent. The RPS may also need to encourage water harvest, storage and recycling.

Permitted water takes should be encouraged to provide their take information to the NRC – this would enable the NRC to start to understand the cumulative effects of permitted water takes within a catchment and give some level of protection for the individuals existing water take.

The effects of climate change on Northland need to be considered, particularly in relation to the potential for drought and the associated implications for water quantity.

This section will need to be closely involved in government initiatives such as the drinking water standards and Water Program for Action to ensure a consistent approach is taken.

Conclusions

This section of the RPS needs to be substantially revisited in response to existing and future pressures, such as increasing demand for water and inadequate management of the relationships between land use and both surface and groundwater hydrology. The development of a sustainable allocation regime and a more holistic approach to the management of land use change and hydrology are key focal points for the future.