Is water quality improving in Waimakariri?
David Ashby, farm environmental consultant and chair of the Waimakariri Zone Committee, recently met a friend who is a small block owner. He’s concerned about the impact of irrigation and dairy farming on the environment and wants to see the Ashley River/Rakahuri flowing year-round along with improved recreational values for kayaking and fishing.
He asked me what the zone committee and farmers are doing to improve Waimakariri’s water quality.
The Ashley River/Rakahuri doesn’t have any large irrigation schemes and there are only a few farmers with relatively small irrigation takes linked to surface water flows.
We’ll be working with farmers in the lower Ashley River/Rakahuri with hydraulically linked wells as part of the solutions package.
Recent dry years and a build-up of shingle and woody weeds have decreased the flow of the Ashley River/Rakahuri. There’s no easy fix. Storage is possible, but this involves environmental considerations and increased cost.
Significant reductions in nitrate levels needed to improve water quality
The Eyre management area which feeds into Silverstream has serious issues and will likely require significant reductions in nitrate levels.
Nine test wells have been drilled alongside the Waimakariri River and we’ve taken samples from 180 wells to investigate water quality and groundwater flows. We’ll have this data in early 2018.
While we’re waiting for this information, we’re concentrating on Farm Environment Plans (FEPs) for farmers who belong to Waimakariri Irrigation Limited (WIL) and those outside the scheme who require a resource consent to farm.
All farmers within Waimakariri Irrigation Limited have completed farm environment plans and audits. Their resource consent requires shareholders to maintain at least an audit grade B.
The benefits of Farm environment plans
Farm environment plans identify waterways and biodiversity, riparian set back, critical point source areas and cultural values. The audit process helps farmers make required changes to improve water quality.
On farms with heavy soils, nitrates aren’t the problem, instead sediment, phosphorous, E coli and pathogens are causing issues. Plan Change 4 has tools to fix these problems, including stock exclusion, which is a statutory requirement for everyone.
Good management practice will fix 90 percent of Waimakariri’s issues on all properties regardless of their size.
This includes irrigation management, such as the justified irrigation project initiated by the Cust Main Drain water user group. This project focuses on: soil moisture monitoring, pasture growth, fertiliser, effluent use, and profitability.
We’re also investigating other solutions including: targeted stream augmentation, managed aquifer recharge and an ESR-led denitrification wall trial. Our first 500 project will protect the first 500 metres around springheads.
Waimakariri’s significant urban and peri urban growth is also impacting our water.
We’ve started a programme for small block owners to discuss land-use, lifestyle block management plans and Environment Canterbury’s farm portal.
Water quality is everybody’s problem and we’re all part of the solution. Instead of playing the blame game, we need to live above the line and work together to achieve positive change.