Horizons has modelled various urban and land management practices (from now on, we'll refer to them as actions) to understand how communities can close the gap between the current state and the target state of the region’s wai māori (freshwater).

Considerable investment has been made by landowners and their partners to identify and implement actions to reduce the impacts of human activities on water quality. We have modelled some of these actions known to reduce the amount of contaminants entering waterways across urban, pastoral farming and commercial vegetable growing environments. These include actions commonly used across the agriculture and horticulture sectors that many landowners across the region have already employed for decades, and some newer actions tested in several locations.

The types of actions we modelled are in the image slider below.

There are some effective actions we haven’t modelled for this engagement. These include initiatives such as using plantain as pasture to dilute nitrogen concentrations in cow urine and improve nitrogen retention in soil. We can add many other viable actions to our kete mātauranga (basket of knowledge) to bolster our contaminant reduction activities, and we are exploring these as part of our Oranga Wai work programme.

If there are any additional actions not discussed here that you think we should consider to achieve water quality targets, let us know by completing the survey found on the water quality targets homepage.

In the map below, we present how far these actions might get us to our provisional target states if all parties implemented the ones relevant to them (i.e., 100% implementation of actions across the region).

We have displayed how close the actions can get us to the target states in a sub-zone using five colours:

• Red | Modelled actions are insufficient, and contaminant must reduce further between 50% and 100% in this sub-zone
• Orange | Modelled actions are insufficient, and contaminant must reduce further between 20% and 50% in this sub-zone
• Yellow| Modelled actions have a moderate impact, and contaminant must reduce further by up to 20% in this sub-zone
• Green | Modelled actions are sufficient and will likely achieve targets
• Blue | Targets for rivers and streams were met before actions in this sub-zone

Correction – January 2024: Horizons and our partners have reviewed our action effectiveness modelling and identified some errors, which led to the original estimates for action effectiveness in some sub-zones being reported incorrectly. These errors have now been corrected. We sincerely apologise for the errors.

Fourteen water management sub-zones have had their category status changed for total phosphorous – seven are now more likely to have actions achieve the periphyton target, while seven are now less likely to have actions achieve the periphyton target.

Seven water management sub-zones have had their category status changed for E. coli. All seven are now more likely to have actions achieve the E. coli targets.

If you want specifics on exactly what has changed, please contact us by emailing info@ourfreshwaterfuture.nz.

Select a specific contaminant from the dropdown menu at the top of the map to see how far actions might reduce it according to our models.

Select the buttons on your right to view the information at the regional or FMU scale, or go to your water-management sub-zone by entering your address in the search bar. You can also use the search bar to see the information for less specific addresses, such as a lake or town.

Tap or hover your mouse over a water management sub-zone to see how close the actions can get us to the target states in that area.

Our modelling indicates the region's water quality will improve if communities in the region implement the modelled actions.

However, these actions alone will not be enough to reach our provisional water quality targets in many rivers and streams across the region.

In environments where the modelled actions are insufficient, we must consider additional actions and further innovations.

In some places, we might also need to consider different scales of land use change to realise the communities’ visions and environmental outcomes. Please remember that no decisions have been made to adopt the provisional water quality targets nor, by default, the scale of change and actions discussed here, and we welcome your feedback on these matters.

There are two timeframes we must consider when talking about the Horizons Region’s water quality targets:

• How quickly central government expect meaningful improvement in the region's water quality. This timeframe is expressed as "within a generation" (approximately 25-30 years).
• How lag times impact how quickly we see potential outcomes.

If everyone across the Horizons Region implemented all the actions we have discussed, it would be some time before we saw water quality improve. This delay is due to a concept called lag times.

It can take years – the lag time – for rainwater to move through the soil into aquifers, some of which will be released into rivers and lakes before exiting through estuaries to the ocean. Some of the effects we see in the water today are decades in the making. In the Horizons Region, the lag time for rivers and streams is typically 0-13 years at low flows.

Check out this video about water allocation to learn more about how wai māori moves over, through and under the land.

We also know it takes time (about 15-20 years) for communities to embrace and adopt new mitigation actions at a meaningful rate. Even if actions are required under regulations, it can still take a few years for communities to navigate and implement what they need to do.

When you add how long these measures take to impact water quality, it can be decades before today's decisions lead to tangible outcomes. For example, suppose you have established trees on your property to reduce erosion. In that case, it can be many years before the trees mature enough to be most effective.

Horizons must set timeframes to achieve water quality targets that are ambitious and reasonable (i.e., difficult to achieve but not impossible). Lag times, as well as social and economic factors, will all influence whether we can consider a timeframe ambitious and reasonable for our communities.