Water Engagement Roundup
The questions and answers from the Water Engagement Roundup webinar recorded on Wednesday 20 March 2024 are below. The topic for this webinar was how environmental water is managed in NSW.
Watch the webinar
Wednesday, 20 March 2024. This month's update was on how environmental water is managed in NSW.
Questions and answers
What modelling is currently used to support environmental watering decision making?
A. The department uses the best-available information to make decisions about environmental water. This can include various types of modelling from inundation modelling, hydraulic and hydrologic modelling, probabilistic climate modelling, etc. We also use a range of decision support systems and of course the wealth of experience held by regional communities and our catchment-based water managers.
When releasing water from Dams or weirs for the environment (or for water supply purposes) what can be done to ensure this is not extracted for irrigation purposes?
A. In regulated systems, WaterNSW use flow gauges, operational modelling and detailed accounting methods to ensure the order from dams reach their delivery sites.
In some unregulated systems, where environmental water is at high risk of extraction, (e.g. Barwon-Darling & Macquarie-Bogan) WaterNSW protect environmental water by following the active management procedures, specifically raising commence-to-pump thresholds by the equivalent volume of environmental water flowing through each zone. Active management annual reviews help to determine if the protection was effective.
The Natural Access Resource Regulator (NRAR) are responsible for checking water user compliance and can investigate and enforce action for any unlawful extraction of water.
What are the key constraints for delivering environmental water when it is most needed?
A. A constraint is any physical, policy or operational barrier limiting the flow of water in river systems. There are a range of flow constraints in the Basin, some examples include:
- physical restrictions, such as low-lying watercourse crossings, weirs and levees
- operational restrictions, such as river operation rules and practices
- policy barriers, such as existing legislation.
Over time, government has been working to make the delivery of water for the environment more effective by addressing constraints that can reduce the outcomes achievable by environmental water e.g., active management procedures in the Barwon-Darling and Macquarie-Bogan systems and Basin Plan Constraints projects.
The Reconnecting River Country Program and Reconnecting Watercourse Country are two Basin Plan Constraints projects proposing to remove constraints to enable the flexible use of water for the environment in the Murray, Murrumbidgee and Gwydir catchments. Relaxing these constraints would allow higher environmental flows to be delivered, as needed, to provide improvements for river habitats, native vegetation, native fish and other fauna.
How do you propose to manage third party inundation from environmental water onto private land. It has been happening for some time with no consequence for Government. How do you propose to make environmental waterers accountable?
A. Environmental water managers are bound by the system rules in each valley and order water accordingly. WaterNSW physically delivers water orders for all water users and runs our rivers on a daily basis. In specific circumstances, water for the environment is intentionally delivered on to private lands by mutual agreement e.g., around 40 private landholders within the Murray Irrigation District benefit from environmental water deliveries onto their properties.
Interested to understand more about how environmental releases work in times of shortages when the timing of releases seem incongruous for towns facing serious shortages of water for critical human need.
A. Under the NSW Water Management Act (2000) when outside of drought periods, water for regional towns has priority over general security (held environmental water) licences and under extreme drought circumstances water for critical human needs is the highest priority. See the Extreme Events Policy (PDF, 974.16 KB) for more details.
What provisions have been made regarding pew and HEW management whilst the reconnecting watercourse program remains unfinished? 10 years from when Murray Darling Basin first offered constraints program and still nothing.
A. The absence of finalised programs to reduce constraints has not prevented the effective delivery of either planned or held environmental water (PEW or HEW) and our monitoring has demonstrated the many amazing achievements environmental water has achieved over the last decade.
For example, planned environmental water has been delivered into the Gwydir wetlands since 1998. Those deliveries have been managed at a release rate capped at 250 ML/d in both the Lower Gwydir and Gingham systems and deliveries have been halted during critical harvest periods in recognition of landholder needs while still achieving environmental outcomes.
The intent of the Reconnecting Watercourse Program is to reach agreement with landholders and put in place mitigations that will allow environmental water managers to deliver at higher flow rates and allow water delivery to continue through summer harvest periods to meet the environmental water requirements of the wetland vegetation and support wetland fauna.
What legal mechanism does the department use to obtain access rights when delivering Held Environmental Water through private lands?
A. The department operates under the Water Management Act 2000 and the relevant water sharing plan provisions in each of the valleys.
Specific agreements with landholders enable delivery of water onto private land to water environmental assets.
Does the water sharing plan or water resource plan list and prioritise environmental assets with annual volume held environmental water delivery targets (ML) for each asset?
A. The long-term water plans describe the environmental assets and the environmental water requirements for these assets.
How do cultural water entitlements (through Water Sharing Plans, Native Title etc) fit in to this framework and what is the % of cultural water entitlement that is realised through allocation each year?
A. Cultural water is not within the purview of environmental water holders. But we recognise that the outcomes being sought by First Nations have a strong overlap with the outcomes being sought by environmental water holders.
We have been working collaboratively in partnership with a range of nations across the state to deliver those co-benefits.
Will NSW also start to protect HEW originating from QLD soon in NSW rivers?
A. Since September 2023, an agreement has been in place with QLD for protection of held environmental water arriving in NSW from the QLD Border River. Some implementation issues have now been resolved and from March 2024 the water will be able to be protected through the Barwon-Darling active management procedures. NSW is now working to develop an arrangement that will enable held environmental water flowing from QLD through the Intersecting Streams plan area to be recognised then also protected in the Barwon-Darling active management procedures.
One of the assumptions during Water Sharing Plan modelling was that held environmental water (HEW) usage would be the same percentage of entitlement as consumptive usage. Will actual held environmental water usage be the same as the assumed modelled usage?
A. Yes, that's correct the assumption during the Water Sharing Plan modelling was that HEW usage pattern was the same at consumptive users. Further modelling work is being conducted to improve the understanding of HEW usage patterns .
It has been acknowledged and accepted by CEWH and the managers of HEW on behalf of the NSW government that the long-term average usage of HEW entitlements will not exceed the long-term diversion level equivalence (LTDLE) factor value. This is the practical outcome of much earlier and high-level government commitments made publicly to “buy back the gap”.
HEW entitlements are not conditioned or restricted to enforce this agreement, so we have retained the plan limit usage compliance mechanism as a safeguard to ensure that HEW entitlement usage cannot grow in an unrestricted way and thereby degrade the value of other equal status entitlements.
Model development work is underway to capture how HEW is planned to be used for incorporation into standard model configurations. That effort builds on a previous attempt and is being driven by the needs of the Basin Plan review. Once finished, environmental water holder behaviour will be a standard model feature much like irrigator behaviour is now.
How is environmental water designed to be returned to above system, hanging swamp locations (e.g., loss through cracking/subsidence).
A. Held environmental water can only be delivered to environmental assets where a release from a water storage or other infrastructure allows physical control of flows. For upper unregulated catchments the protection of environmental assets is achieved by limiting the extraction of consumptive water. This can be achieved by rules that set when pumps can operate and/or by buying entitlement and reducing the overall extraction in a valley.
Why don’t the effluent creeks receive any environmental water from the State or Commonwealth when it is the only natural way for water to reach the Murray Darling Basin? Noting the marshes uses the man-made Northern Bypass Channel to reach the Barwon.
A. It is a common misconception that the Macquarie River does not connect to the Barwon River. Environmental water is delivered to the Barwon River via the lower Macquarie River downstream of the Macquarie Marshes, through the northern marsh wetlands and in fact only recently stopped flowing since the drought broke in 2020. The north marsh bypass channel is closed during environmental water deliveries.
The effluent creek system in the Macquarie is identified as an environmental asset and is considered a potential target for environmental water. However, as the Gunningbar, Duck and Crooked Creek systems get regulated water usually 365 days per year, it is lower priority than other parts of the system that regularly dry out if environmental water is not supplied.
"Given that water management is so highly controlled, what is considered a 'Natural Water Event?' Helen's farm has water from inundation from releases that are not 'rainfall'. What is the definition of a natural water event?"
A. A “natural flow event” could be considered any flow event that is not the result of a release from an upstream storage, e.g., events arising from local rainfall or upstream tributary inflows.
If the Gwydir is a terminal wetland (stated earlier in your presentation), and environmental water is piggy backed with other water, how do your account for the losses out the other end of the system which are inundating private land?
A. Piggy-backing environmental water with other water refers to a scenario where environmental water managers request environmental water to be released to coincide with other flows in the system (such as irrigation deliveries) to increase the peak flow rate to achieve an environmental outcome. An example might be additional water released on top of peak irrigation flows to drown out a small weir. So, instead of 4,000 megalitres per day for example, the flows might increase to 5,000 megalitres per day.
Environmental water managers do not piggyback environmental water in the Gwydir wetlands to increase the peak flow. However, we will often combine different sources of environmental water to increase the duration of a flow event, for example we might follow a 3T flow event withheld environmental water to achieve watering objectives, like watering wetland vegetation or filling significant waterholes. Flow rates are limited to reduce impacts on private land, however, land in low lying areas of the watercourse may be inundated.
In the upper catchment (technically unregulated) but quasi regulated downstream of Suma Park Dam and Chifley Dam (Local Government Water Utilities Dams for Orange and Bathurst) due to the dam operating requirements for environmental releases. Irrigators were not given any restrictions in the last drought and was based on the visible flow regime. Dams were emptied quickly as irrigators took up that water. Why aren't restrictions put on these unregulated irrigators?
A. During the drought access for licence holders between Ben Chifley Dam and Bathurst had their available water determinations reduced to assist in protecting town water releases as there were limited options to restrict access to daily flows. However the drought highlighted the current rules in the water sharing plan which manage licensed extraction where not providing adequate protection for town water releases.
The Water Sharing Plan for the Macquarie Bogan Unregulated Rivers Water Sources 2012 (the plan) was extended for 2 years based on a recommendation from the Natural Resources Commission and will expire on 1 July 2025. This provides an opportunity to review the access rules for these specific areas to ensure releases for town water supply are better protected. The department is currently reviewing these rules and developing alternate options for further discussion with key stakeholders. The draft plan is expected to be placed on public exhibition in the later half of 2024 and feedback will be sought from the community.
The Macquarie-Castlereagh Regional Water Strategy was released in October 2023 and is currently in its implementation phase. Town water security for Bathurst and Orange was a key issue considered during its development and a suite of tailored actions were identified that aim to secure water for the towns during drought. This includes improving our understanding of the Upper Macquarie system through better gauging and development of a new hydrological model, collaborating better with council to help make limited water sources last longer, and investigating augmentation options such as pipelines and stormwater harvesting to improve the availability of water during dry conditions. The strategy will help councils to be better prepared for future climate risk and growing populations over the short and longer term.
When we release water from our Clarrie Hall Dam in Tweed Shire to meet Minimum Environmental Passing flows at a downstream Bray Park Weir (which is also our town water extraction point), there are no restrictions on irrigators in route. We end up releasing far more from the dam water. FYI - Tweed is also defined as unregulated.
A. Irrigators in the Mid Tweed River Water Source must cease to pump water when the Tweed River flow is below 4ML/day at the Palmers Road Gauge (201015). This includes irrigators within the Bray Park Weir pool. Water Utilities are exempt from this cease to pump level as water is released from Clarrie Hall Dam for water utilities. Water is also released from Clarrie Hall Dam to allow for water flow through the fish ladder at Bray Park Weir. There will be times when the Tweed River flow is above 4ML/day at the Palmers Road Gauge and there are releases being made from Clarrie Hall Dam. However, irrigators must not pump water when the Tweed River flows are below 4ML/day at the Palmers Road Gauge.