Local Government Magazine
3 Waters Technology

What's WAT?

Northland Regional Council has a detailed and accurate big-picture view of how much surface and groundwater is available in its region. Its water allocation tool (WAT) is an integral part of decision-making, helping council balance the needs of ecology and people, make decisions faster and streamline consents processes.

Janelle Palmer.

First developed in 2014, Northland Regional Council’s water allocation tool (WAT) meant council could, for the first time ever, see at a glance how water was allocated in its region.

It showed which catchments were over-allocated and enabled council to focus its resources into those areas. “This level of insight was really valuable to our teams,” says Northland Regional Council’s geospatial analyst Janelle Palmer. “I can’t emphasise that enough.”

Janelle was speaking at the recent ALGIM Autumn Conference 2018 in Wellington. She went on to say that, although she was about to critique the limitations of the first version of WAT – and outline subsequent adaptations and their benefits – it was a “big deal” at the time to be able to get such a big-picture view.

“However,” she said, “it quickly became apparent that this level of detail, which is sources and catchments, was not fine enough for us to use for decision-making.”

Janelle emphasised that water is a primary focus at Northland Regional Council. “It’s our job to ensure there is enough water for everyone and that we maintain the quality of water for future generations. With over 127,000 reaches in the Northland region, it’s a large and significant resource for us to manage.”

Over-allocated catchments are shown in orange.

Water allocation is an essential part of water management, she said. “It’s the process of determining how much water we can take from our various rivers and aquifers, and how much more is available once we’ve taken from them. The science behind water allocation is quite complex with many factors in play.”

Janelle said that while her presentation focused on surface-, rather than ground-water, both are included in its water allocation tool.

“The big question in water allocation is how much water can be taken from a reach without a negative impact,” she said. “There’s two parts to that. The first is environmental protection. That looks at how much water can be taken without affecting the flora and fauna within our streams.

“What we’re talking about there is minimum flow. This ‘magic number’ looks at the sensitivity of flow within a stream. Different streams have different sensitivities based on the ecology within them. Some native fish species, for example, need to have a certain level of flow for them to survive.

“On the other side of the equation is the security of supply. When someone applies for consent to take water we need to know how reliable that supply is. That’s important because, particularly in Northland, the levels of our rivers change quite significantly from summer to winter, and from drought to flooding.

“The ‘magic number’ in that case is called the allocation limit and that value is set by the regional council in our regional plan.

“Those two magic numbers have a relationship and that is, pretty much, the essence of water allocation.”

Janelle described WAT as “a collection of ArcGIS models and scripts” that enables NRC to see which rivers and aquifers are under pressure and where any restrictions are needed.

Minimum flow and allocation limits are the integral parts of Northland Regional Council’s water allocation tool (WAT).

CHALLENGES & ENHANCEMENTS

While the first version of WAT added considerably to NRC’s understanding, council’s hydrologist Susie Osbaldiston could see opportunities for improvement. Susie and Janelle became the water allocation tool team.

Initially, council was only looking at catchments, for example. “They are quite large catchments when you’re doing source-to-sea as well,” said Janelle. “So, we wanted to get right down to the reach level: to individual branches of a river.”

That meant consent data had to be improved. “In the beginning, our staff didn’t really understand the importance of entering that data accurately so that it could be pulled into the tool at the reach level,” said Janelle.

“Susie spent quite some time educating staff about the importance of that. But it didn’t really hit home until our staff were able to see the value in the outputs from the tool. Then they were more motivated to give quality data in order to produce quality outputs.”

Resourcing the project was another issue. “We had quite a large body of work that needed to be done,” said Janelle, “so we decided to cut it into discrete little sections of work.”

“The first advantage was we only had to focus on one part of the tool at one particular moment. The other advantage was we were able to get the work done as business as usual because they were two- or three-week blocks of work rather than a massive project that needed to go through a formal resourcing process. So, we staggered projects across the year until we got what we were after.”

REFINEMENTS

The benefits were many. Janelle explained that, in addition to calculating at the reach level, the revised tool now also applied the allocation up the river network. That gave a more accurate picture of water allocation in the region.

The ability to apply more real-world data to WAT also improved accuracy. Other improvements to the quality of the data came from refining the recharge algorithms for groundwater.

“We also spent a lot of time improving the reclassification of the ecological sensitivity of the streams,” said Janelle. “That was a result of our Regional Plan work, where we were having to set these allocation limits. We really wanted to understand the ecology of our rivers a lot better and feed that back into the model.”

Further refinements came from improving the boundaries for groundwater aquifers and lifting the usability of the tool. “I did quite a bit on improving the structure of the model; naming things well; documenting the tool well; all that kind of work to reduce the learning curve for the next person coming through.”

NRC also automated the model “so that each time the tool was re-run it was not a big laborious process and it wasn’t as time-consuming”.

BENEFITS

The outputs from the tool are now an integral part of decision-making at Northland Regional Council. The enhancements made improve both the quality of the data and council’s confidence in the tool and its data sets. The benefits were many and spread across multiple parties.

ACCURACY / POLICY REQUIREMENTS

Council’s hydrology team, the biggest users of the tool, all of a sudden had the accurate and detailed picture they were after, said Janelle. They could identify, and get research on, reaches that were under pressure. They were also able to meet central government reporting requirements under the National Policy Statement on Freshwater Management (NPS-FM) – one of the initial triggers for needing the tool.

The hydrology team also no longer had to generate individual water allocation documentation. “In the past, each time a new resource consent came in, we would have to go to that particular reach and do essentially what the tool is doing now, but manually and individually, and a different person might do it slightly differently each time. Now, hydrology no longer had to take on that role.”

CONSENTS

For council’s consents team, there were similar benefits. The “big picture” view made it easy for the team to see, at a glance often, whether or not a consent would be likely to be passed.

“That significantly reduced the amount of time they took processing consents for our water takes and bores. It also made it a lot easier for them to explain to people why they couldn’t get a consent. It’s really easy to show a picture with a big red line through it and say, ‘that’s why’.”

The team now also had a standardised and consistent approach to water allocation documentation.

PLANNING

For the planning team, the results were “interesting”, said Janelle. “They could suddenly see the impact of the decisions they were making, because these are the guys that are setting the allocation limits in the first place. I remember the first time they saw the maps and realised the impact that their policy was having on our region.”

Fast forward to the most recent round of policy-setting for the regional plan, and planners could see a variety of scenarios through the tool. They could visualise what would happen if they set the allocation limits at different levels.

“That helps them make better decisions now,” said Janelle, “and we do future scenario planning as well.

Water allocation balances environmental protection and security of supply.

THE PUBLIC

One unexpected, and unplanned for, advantage was for the public. WAT had initially been conceived as an inhouse tool. But, as Janelle explained, council realised that the quality and robustness of the data set was such that it could be delivered to the public.

So, when NRC released its proposed regional plan in September last year, it decided to include the outputs from the water allocation tool.

“This was the actual data that we are using for decision-making [being put] out there in the public domain. That was a pretty big deal at the time. It meant the public could understand allocation limits as set out in the regional plan.”

Importantly, members of the public could also see by glancing at the maps whether any idea they had about water takes – such as the possibility of setting up a water-thirsty commercial enterprise in a particular place – would be likely or not.

“That created a sort of self-service scenario which reduced the number of inquiries we were getting for consents as well,” said Janelle.

“It also reduced the complexity of the planning and presenting the regional planning data because it was visual, easy to understand, and it just looked simple: even if the science behind it was not.”

Janelle added that sharing such information improves the transparency of council’s processes and helps increase public confidence that NRC is taking into account the ecological impacts that water takes are having on the region’s rivers. “It shows that we are taking the health of our rivers seriously.”

WHAT’S WAT’S FUTURE?

So, what’s next for WAT? “Better data for some of our data sets,” said Janelle. “For example, Northland is getting a Northland-wide LIDAR data set in the near future. So, we will be able to derive a more accurate river network from that.”

She noted that NRC already has a “pretty good” understanding of its river network. “But because we have some quite flat areas, the model is showing those as straight lines when they’re not.”

NRC also wants to include more outputs in its accumulation. “We’d like to investigate whether it would be possible to get stock water use data at the reach level,” said Janelle.

“And there will also be further refinement of the tool as our staff go out and collect data about river levels and the ecological sensitivity of rivers. That will all get fed back in.

“Also, as other organisations such as NIWA do better modelling we’ll include that into the tool as well.”

For Janelle, the biggie would be modelling and presenting groundwater data in 3D. If council could get the data – and it is not yet sure whether that will be possible – 3D imagery would have the same kind of impact as changing the surface water from catchment to reach level.

“I mean, aquifers don’t exist in blocks, they exist in substratas,” said Janelle. “So, to be able to more accurately model the difference between drilling a bore here or over there will give us an even clearer picture and we’ll be able to manage that resource better too.”


This article was first published in the August 2018 issue of NZ Local Government Magazine.

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