Frequently Asked Questions

Have you got a question about Rotorua Lakes management and restoration?

Ask Bay of Plenty Regional Council and we will summarise common questions and their answers on this webpage. All visitors to the website may benefit from reading the answer to your questions.

What is Rule 11, and how will it affect rural landowners in the Rotorua Lakes catchments?

Rule 11 is a commonly used term for a collection of rules in the proposed Regional Water and Land Plan that will restrict landowners in some of the Rotorua Lakes catchments from increasing the amount of nitrogen and phosphorus leaving their property. These rules have important implications for land use, development and management in certain lakes catchments. Read the Rotorua Lakes Factsheet on Rule 11.

I live beside Lake Rotoiti and our household uses a septic tank system. What new requirements are there in the revised On-Site Effluent Treatment Regional Plan, and from when do they apply?

Refer to the On-Site Effluent Treatment Regional Plan - Regional Rules are contained in Chapter 5. Contact Bay of Plenty Regional Council for more information.

What is an acceptable (ideal) level of nitrogen and phosphorus leaching for various land uses?

Bay of Plenty Regional Council has worked from the principle of setting the acceptable level of nutrients in the lake (and the associated lake water quality) based on public consultation. From that we can work out what the maximum nutrient load from the catchment should be. If the existing load is too high then either the land uses or the land management practices are not acceptable.

For productive land use systems, the potential for leaching nitrogen generally follows this order: forestry < sheep/beef/deer farming < arable/mixed cropping < dairy farming < vegetable cropping. Below is a summary of researched nitrogen losses for different land uses in New Zealand.

As you can see, there is a very large variation in nitrogen losses, so it is hard to place an overall ideal for each land use type, especially as soil type and climate vary. But there are some management practices that can substantially reduce nutrient leaching, such as wintering off stock, riparian protection, appropriate fertiliser application and erosion control. Bay of Plenty Regional Council's land management officers can also assist with farm nutrient management.

Is there an ideal fencing distance from the water's edge and a preferred type of plant for riparian protection? What distance from the edge of lakes and rivers and what density of planting is required?
The width and composition of a riparian (river/lake/wetland edge) protection area depends on its purpose: stream restoration, nutrient reduction, wildlife corridor, stock protection, woodlot planting. The ideal width and plants to use is also site-specific, though there are general principles for different types of riparian strips. Bay of Plenty Regional Council has fact sheets on this and landowners can also get free advice from Bay of Plenty Regional Council land management officers.

Are there any proposals for extracting and using the phosphorus and nitrogen leached from land before they reach the lakes and start causing problems?
There is a proposal to trial flocculant dosing in the Puarenga and Utuhina streams, which flow into Lake Rotorua. Flocculants are chemicals that bind with dissolved phosphorus so the phosphorus settles out onto the stream or lake bed and cannot be used by aquatic life. Other proposals include using geotextile socks filled with material that can absorb ammonium or phosphorus (in different cases) in streams that enter the Rotorua lakes. It may be possible to extract the nutrients for fertiliser use, but these materials may also absorb other compounds that are not desirable in fertiliser.

There are often obstacles to be overcome before these techniques can be used, including cost, environmental effects and cultural impacts. They are not a substitute for reducing nutrient loads to waterways, but can be a short-term solution in some instances.