NSW Environmental Protection Agency NSW Government
 

Annual Compliance Report 2024: Snowy Hydro Limited Cloud Seeding Program

Summary of findings

The EPA has reviewed Snowy Hydro Limited’s annual compliance report for the 2024 cloud seeding season and has found that:

  • no cloud seeding operations were conducted in 2024, to allow a comprehensive economic review of the Cloud Seeding Program
  • the compliance report was submitted to the relevant Ministers and the EPA on time
  • Snowy Hydro has complied with all of its obligations as detailed in the Act
  • Snowy Hydro generally complied with all its obligations in the Environmental Management Plan.

Find out more about the Snowy Mountains Cloud Seeding Act (2004) and the cloud seeding operations.

To date, independent studies have found no conclusive evidence of an increase in silver concentrations due to cloud seeding activities, nor have stakeholders raised any current or emerging issues since the commencement of cloud seeding operations.

Review and consultation

The EPA has undertaken its review of Snowy Hydro's 2024 Annual Compliance Report, in accordance with the Act and the approved Environmental Management Plan. In carrying out its review of the report, the EPA consulted with the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW)'s Environmental Protection Science section. The EPA also consulted with the National Parks and Wildlife Service (NPWS) in respect to cloud seeding operations that took place within Kosciuszko National Park.

DCCEEW commented that:

  • Potable water results: based on the reported data it is unlikely that there are any direct potential human health risks attributable to the concentrations of silver in water within the cloud seeding target area
  • Soil monitoring: despite Snowy Hydro attributing elevated silver levels in two soil samples to bushfire impacts, appropriate justification for this assertion is not provided. While not required in the Environmental Management Plan protocol, this justification should be provided.
  • Ecological monitoring: consideration of ecological risk is recommended for future sampling events, including trialling passive and/or auto-sampling to evaluate potential exceedance of ecological guideline values for silver. The EPA notes that this was discussed by the Review Committee during the 2023 review of the Environmental Management Plan and is not relevant for the purposes of this Annual Compliance review. The EPA will continue to liaise with DCCEEW and Snowy Hydro regarding this recommendation.

NPWS reported that no issues were noted during this reporting period, and minimal maintenance and decommissioning projects were undertaken and reported to NPWS.

Findings

The review of the 2024 Annual Compliance Report found that:

  • Snowy Hydro has complied with all its obligations as outlined in the Act.
  • Snowy Hydro complied with all its obligations within the Environmental Management Plan.
  • No cloud seeding operations were undertaken in 2024 and therefore no cloud seeding agent was dispersed over the Target area.
  • There were no accidents or breakdowns resulting in spillage of cloud seeding agents or fuel, or failure of controls specified in the Environmental Management Plan.
  • Monitoring was carried out in accordance with the Environmental Management Plan.
  • Analysis of the monitoring data did not detect any evidence of significant adverse environmental impacts associated with cloud seeding activities. Specifically:
    • Analysis of precipitation amounts over 1990–2024 continue to show no evidence of an effect from cloud seeding on precipitation downwind of the Target Area.
    • Analysis of silver concentrations from samples collected through the program up to 2024 show no evidence that cloud seeding is contributing to broadscale increases in any area or in any environmental matrix monitored. Concentrations of silver continue to show significant spatial and temporal variation between sites and years.
    • Concentrations of total silver in two soil samples (out of 36 samples analysed) were above the Guideline Trigger Value. This is suspected to be related to fire activity from the 2019/2020 bushfires. Bioavailable silver analysis in these two samples indicate bioavailable silver volumes are well below the Guideline Trigger Value.
    • Silver concentrations in potable water samples, including those collected in 2024, remain several orders of magnitude below relevant guideline values.
  • Cloud seeding is not having a measurable effect on the concentrations of silver in various parts of the environment.
  • There were no new operations involving land-based methods of discharge of seeding or tracing agent within any area of land managed under the National Parks and Wildlife Act 1974.
  • Modifications to infrastructure were undertaken at two precipitation gauge sites to remove damaged infrastructure. NPWS were notified of the proposed changes. No new facilities for cloud seeding operations were installed.
  • No agencies requested consideration of any emerging environmental issues within this reporting period.

Discussion

During 2024 cloud seeding operations, Snowy Hydro did not undertake any cloud seeding operations. Following the end of the 2023 cloud seeding season, Snowy Hydro began a comprehensive economic review of the Cloud Seeding Program, including resourcing and infrastructure requirements and ongoing return on investment. Snowy Hydro paused cloud seeding operations in 2024 to undertake the review.

During the 2024 cloud seeding season, there were no new operations involving land-based methods of discharge of seeding or tracing agent within any area of land and no accidents or breakdowns resulting in spillage of cloud seeding agents occurred. There were no changes to infrastructure sites through 2024, except for modifications to 2 precipitation gauge sites to remove damaged infrastructure. NPWS were notified of these proposed changes. No new facilities for cloud seeding operations were installed.

Maintenance continued at weather stations through 2024, however not all weather stations were commissioned and operational through the winter season.

The Environmental Management Plan includes an adaptive environmental monitoring program where the future program is informed by the results of the previous environmental monitoring. Based on the analysis of samples collected from 2004 to 2023, the Environmental Management Plan's prescribed 5-year interval between environmental monitoring programs was found to be appropriate.

In accordance with the Environmental Management Plan and the outcomes of the environmental chemistry analyses reported in the 2023 Annual Compliance Report (Snowy Hydro 2024), all potable water sites and 2 generator soil sites were required to be sampled following the 2024 winter season. An additional soil generator site that recorded one sample above the Guideline Trigger Value in 2023 was also sampled and reported on.

Silver concentrations remain several orders of magnitude below relevant guideline trigger values, except for the concentration of total silver in 2 soil samples (out of 36). While not prescribed under the Decision Tools in the Environmental Management Plan for the 2024 results, bioavailable analyses were undertaken on these two samples. This analysis showed that bioavailable volumes of silver in these two locations remain extremely low and well below the Guideline Trigger Values.

Analyses of data collected following the 2023 season has shown no evidence of any difference over time in the impairment of the macroinvertebrate assemblages or multivariate structure of edge or riffle assemblages.

While no current or emerging issues were formally raised by stakeholders for the 2024 cloud seeding season, mechanisms within the Environmental Management Plan allow relevant agencies of the Minister for the Environment to request consideration by Snowy Hydro of emerging environmental issues between each 5-yearly review.

Conclusion

After reviewing Snowy Hydro's 2024 Annual Compliance Report, the EPA concludes that:

  • Snowy Hydro has complied with all its obligations as detailed in the Act.
  • Snowy Hydro has complied with all its obligations as detailed in the Environmental Management Plan for cloud seeding operations approved by the relevant Ministers in July 2023.
  • Snowy Hydro has complied with all its obligations as detailed in the Protection of the Environment Operations Act 1997.

The EPA recommends that:

  • monitoring be continued as per the schedule of the Environmental Management Plan, and data compared over time to identify trends.
  • future reviews are also undertaken in consultation with input from partner agencies of the NPWS and DCCEEW
  • the outcomes of this review are communicated to the relevant Ministers.
  • Snowy Hydro continues to liaise with the EPA regarding the future intentions for Cloudseeding operations.
  • Comments from DCCEEW and NPWS will be communicated to Snowy Hydro for consideration.
Obligations under the Snowy Mountains Cloud Seeding Act 2004

Compliance status

(report reference)

Condition 4 (2)(a): The area to be primarily targeted for the increased precipitation is land within the Snowy water catchment.(1.4) Addressed
Condition 4 (2)(b): Operations may be carried out only if there is an approved Environmental Management Plan.(1.1) Addressed
Condition 4 (2)(c): Operations must be carried out in accordance with the approved Environmental Management Plan (whether being carried out within or outside the Snowy water catchment).(1) Addressed
Condition 4 (2)(d): The seeding agent used must be an approved seeding agent and used in accordance with the conditions (if any) of its approval as a seeding agent.(2.2) Addressed
Condition 4 (2)(e): The tracing agent used must be an approved tracing agent and used in accordance with the conditions (if any) of its approval as a tracing agent.(2.2) Addressed
Condition 4 (2)(f): The seeding agent and tracing agent must be discharged by the use of an approved method.(2.2) Approved
Condition 4 (2)(g): The discharge must be carried out in accordance with the conditions (if any) of its approval as a method of discharge.(2) Addressed
Condition 4 (2)(h): The discharge of the seeding agent is to be carried out at a time when increased precipitation in the Snowy water catchment is likely to fall as snow at an elevation above 1400 metres from the mean sea level.(3.1) Addressed
Condition 4 (2)(i): Snowy Hydro Limited must consult with the NPWS before carrying out any new operations involving a land-based method of discharge of seeding or tracing agent within any area of land reserved under the National Parks and Wildlife Act 1974 (that is, operations in an area that has not been the subject of previous consultation with the NPWS).(2.3) Addressed
Condition 4 (2)(j): Snowy Hydro Limited must consult with the NPWS before installing, or carrying out major modifications to, any facilities required to carry out cloud seeding operations within any area of land reserved under the National Parks and Wildlife Act 1974.(2.3) Addressed
Condition 4 (2)(k): Installation of new facilities for cloud seeding operations must not be carried out within any wilderness area (within the meaning of the National Parks and Wildlife Act 1974).(2.3) Addressed
Condition 4 (2)(l): A seeding agent is not to be discharged from land-based aerosol generators in any wilderness area (within the meaning of the National Parks and Wildlife Act 1974).(1.4) Addressed
Condition 4A (3): An application for approval of the use of a thing as a seeding agent in cloud seeding operations must be accompanied by details of the health risk assessment carried out in relation to the proposed use of the seeding agent (including the process used to carry out the assessment and the results of the assessment).(N/A)

Condition 4B (3): An application for approval of the use of a thing as a tracing agent in cloud seeding operations must be accompanied by details of the health risk assessment carried out in relation to the proposed use of the tracing agent (including the process

used to carry out the assessment and the results of the assessment).

(N/A)
Condition 5 (4): An application for approval of an Environmental Management Plan must be accompanied by an independent scientific assessment of any proposed cloud seeding operations that differ from the operations currently authorised. Any such scientific assessment must comply with any requirements imposed by the relevant Ministers and notified to Snowy Hydro Limited.(NA)

Condition 6A (1): Snowy Hydro Limited must, by 31 March in each year or such later date as agreed by the relevant Ministers, provide a report on its cloud seeding operations during the period of 12 months ending on 31 December in the previous year to the relevant Ministers and to the EPA. Without limiting the generality of subsection (1), the report must contain the following information:

  • details of compliance with the approved Environmental Management Plan
  • details of research concerning, and monitoring of, the impact of tracing agents and seeding agents on the environment (including the findings of any such research or
    monitoring).
(4) Addressed
Report on cloud seeding operations received by EPA 31 March 2024.
Obligations under the Environmental Management Plan

Compliance status

(report reference)

Cloud seeding will only proceed if increased precipitation in the Snowy water catchment is likely to fall as snow at an elevation above 1400 metres from the mean sea level. Cloud seeding will be suspended or terminated if rain is observed above 1400 metres during cloud seeding operations(3.1) Addressed
Snowy Hydro will consult with the NPWS prior to undertaking major vegetation management and site access beyond maintenance of the existing tracks and site footprints.(2.3) Addressed

The Annual Compliance Report will include:

  1. Details of compliance with the approved EMP
  2. Details of research concerning, and monitoring of, the impact of tracing agents and seeding agents on the environment (including the findings of any such research or monitoring. This will include sample locations, data results, evaluation and adaptive management recommendations for the environmental monitoring program; and details (including results and evaluation) of any emerging environmental issues
  3. Results from meteorological monitoring that can demonstrate Snowy Hydro’s compliance with the requirement to ensure that increased precipitation falls as snow in areas at an elevation above 1400 metres above sea level
  4. Results from analyses of downwind precipitation
  5. The event time and duration over which cloudseeding occurred
  6. Any accidents or breakdowns resulting in spillage of cloud seeding agents, fuel, or failure of controls specified in the Environmental Management Plan, and
  7. The quantity of cloud seeding agents that were released per seeding event per generator
(a – 4.1-4.3) Addressed
(b – 4.4) Addressed
(c – 3.1) Addressed
(d – 3.2) Addressed
(e – 2.1) Addressed
(f – 2.3) Addressed
(g – 2.2) Addressed

In addition to the Annual Compliance Report, Snowy Hydro will also prepare a Cloud Seeding Operations Annual Report which is to be made publicly available on the Snowy Hydro website within a reasonable timeframe after any recommendations from the Board of EPA and the relevant Ministers.

The Cloud Seeding Operations Annual Report will include, but not be limited to:

  • Summary statistics of the Environmental Monitoring Program
  • Details of compliance with approved Environmental Management Plan
  • Summary statistics on the overall duration over which cloud seeding occurred and the total amount of cloud seeding agents that were released over the season.
(1.2) N/A

Disputes between NSW government agencies and Snowy Hydro with regards to cloud seeding operations will be resolved in accordance with the following escalation process:

  • Use of established paths of communication between Snowy Hydro and the agency (officer to officer)
  • Communication between Snowy Hydro Executive Officer and agency Department Director
  • Communication between the Chief Executives of Snowy Hydro and the agency.
(2.4) Addressed
Snowy Hydro will continue to consult with other relevant land managers with respect to vegetation management and site access. Snowy Hydro will also consult with relevant land managers in situations where major visual modifications are made to infrastructure or if new sites are installed and/or existing sites are removed. No new infrastructure will be established without the prior endorsement by the relevant land manager.(2.3) Addressed
DCCEEW, the EPA and other identified stakeholders will be advised as soon as practicable following the commencement and conclusion of cloud seeding campaigns.(2.1) Addressed
Existing sites authorised under the Act will be defined by Snowy Hydro (coordinates and identified on a map), and provided to NPWS and the EPA prior to commencement of first annual winter operations. Thereafter, prior to the installation of any new authorised sites, updated coordinates and maps are to be provided to NPWS and the EPA.(1.4) Addressed

Implement all Management Controls (Table 1 in the Environmental Management Plan), being those included for each of the following activities:

  • Installation and modification of generators
  • Operation and maintenance of generators (including release of cloud seeding agents and increased precipitation)
  • Storage and preparation of cloud seeding agents and other chemicals
  • Installation and modification of weather stations
  • Installation and modification of communications equipment
  • Operation and maintenance of weather stations and communications infrastructure
  • Operation and maintenance of snow sampling sites
  • Environmental Monitoring Program, and
  • Removal of infrastructure and rehabilitation of sites.
(2.3) Addressed
Meteorological monitoring
Undertake monitoring of downwind precipitation - mean wintertime daily precipitation anomalies will be updated each year and included in the Annual Compliance Report following cloudseeding operations to continue to monitor downwind precipitation.(3.2) Addressed
Snow sampling profile sites and preferred access routes will be defined by Snowy Hydro (coordinates and identified on a map) and provided to NPWS and EPA prior to commencement of first annual winter snow sampling operations. Updated coordinates and maps are to be provided to NPWS and EPA if sites change.

(1.4) Addressed

No snow profile sampling took place in 2024.

Environmental chemistry monitoring
Environmental sampling to be undertaken as per Table 3 in the Environmental Management Plan.(4.1.2) Addressed

Specific quality controls applied to the collection and handling of all samples collected for the cloud seeding program include:

  • The use of a new clean plastic vial/bag for each sample
  • The use of a new pair of clean disposable gloves at each site and procedures to minimise contact with the inside of vials/bags to minimise the potential for sample contamination
  • All sampling equipment is washed with ultra-pure water or water from the sampling location prior to use
  • The use of a data management system including the barcoding of each sample to ensure every sample is individually trackable from collection, return to base, dispatch to the laboratory and the return of results.
(4.1.3) Addressed
Samples sent for laboratory analyses will be analysed for total silver concentration with an appropriate level of quality assurance and quality control (QA/QC).(4.1.3) Addressed
For those samples that are analysed chemically, the data is to be analysed statistically and interpreted on the basis of three statistical tools.(4.1.5) Addressed
Implementation of steps in decision tools and environmental suspension criteria.(4.1.5) Addressed
Macroinvertebrates monitoring
Sampling will be undertaken on a 5-year sampling interval, with the first round of sampling to be undertaken following the first year of cloudseeding operations. In the event that additional river sediment sampling is required as a result of the triggers outlined in the Environmental Management Plan, macroinvertebrates sampling will also be undertaken at the affected locations.(4.2) Addressed (n/a)
If macroinvertebrate sampling sites are changed and/or added outside of the Environmental Management Plan Review process, updates to the Environmental Management Plan will be provided to EPA/NPWS prior to sampling being undertaken.(4.2) Addressed (n/a)
The macroinvertebrate sampling program implemented by Snowy Hydro (and endorsed by DCCEEW) uses the NSW Australian River Assessment System (AUSRIVAS) protocol.(4.2) Addressed (n/a)
Additional monitoring

Relevant agencies of the Minister for the Environment may request consideration by Snowy Hydro of emerging environmental issues between reviews of this Environmental Management Plan.

In order for issues to be considered by Snowy Hydro, the agency will provide a clear outline of the issue to Snowy Hydro based on direct evidence or established scientific theory. The agency and Snowy Hydro will then agree on an appropriate research/monitoring/consultation/reporting regime.

(4.4) N/A