"Horizons is well positioned in water quality management and we are already seeing tangible improvement in water quality throughout the region in the last decade."
He said data between January 2006 and December 2015 showed effort was being made by many in the area including councils, iwi and landowners. Horizons monitored 16 Manawatu sites and 36 in their catchment.
During this time Horizons found all 16 sites improved on a number of factors, with the key swimmability indicator E-coli dropping 31 per cent.
Approximately 75 per cent of these sites also showed improved levels of nitrogen and phosphorus.
"This has been done through regulatory and non-regulatory means such as the Sustainable Land Use Initiative, the Manawatu River Leaders' Accord and the Horowhenua Lake Accord," Dr Roygard said.
"Planting of 110,900 native plants along waterways, erecting 474km of extra stream fencing, completing 98 environmental farm plans, 12 fish passage enhancements, 19 community-led projects, and the upgrade of six wastewater treatment plants have contributed to moving 600 kilometres of the Manawatu catchment into a more swimmable category."
The new national target is in line with European and United States definitions and is expected to cost $2 billion over the next 23 years.
Minister Smith said it was an ambitious goal that would rely on new regulations around excluding stock from waterways, policy requirements on regional councils to strengthen rules around things such as sewage discharge and planting riparian margins.
"This 90 per cent goal by 2040 is challenging ... It will return our rivers and lakes to a standard not seen in 50 years while recognising that our frequent major rainfalls mean a 100 per cent standard is not realistic."
The target covers the length of rivers over 0.4m deep and the perimeters of lakes greater than 1.5km, and is based on meeting water requirements 80 per cent of the time.
The NPS is being strengthened to support the new target, as well as changes to address the issues of ecological health and nutrients by:
* Replacing 'wadeable' with 'swimmable'.
adding macroinvertebrate monitoring for ecological health.
* Strengthening references to 'Te Mana o te Wai'.
* Clarifying the consideration of economic opportunities.
* Requiring instream limits for nitrogen and phosphorus.
* Clarifying inclusion of coastal lakes and lagoons.
* Clarifying the policy on exceptions.
* Strengthening the requirement for monitoring and improving quality.
