2022 Annual Compliance Report: Snowy Hydro Limited Cloud Seeding Program

The EPA has reviewed SHL’s annual compliance report for the 2022 cloud seeding season and has found that:

the compliance report was submitted to the relevant Ministers and the EPA by the due date
SHL has complied with all of its obligations as detailed in the Act
SHL complied with all its obligations in the Environment Management Plan.

Snowy Hydro Limited (SHL) has been conducting a winter cloud seeding trial in the NSW Snowy Mountains area since 2004. On 31 May 2013 amendments to the Snowy Mountains Cloud Seeding Act 2004 (the Act) came into effect enabling SHL to conduct permanent cloud seeding operations within an expanded area of the Snowy Mountains, in accordance with an Environmental Management Plan approved by relevant Ministers. The Act defines the relevant Ministers as the Minister for the Environment and the Minister for Planning and Environment, who approved the Environment Management Plan on 28 June 2018. The Environmental Management Plan is currently under review by the NSW Government.

The Act also authorises aerial application of existing and alternative cloud seeding chemicals, and prescribed a review and oversight role for the NSW Environment Protection Authority (EPA). SHL is required to provide a report to the EPA detailing its compliance with the Environmental Management Plan and the results of any research and monitoring into the impact of cloud seeding operations on the environment by 31 March each year. The EPA is required to review this report and convey its findings, along with any recommendations, to the Board of the Environment Protection Authority and the relevant Ministers.

Cloud seeding expand

Cloud seeding is a process used to improve the capacity of orographic clouds (clouds formed as moist air rises over mountains) to yield precipitation as snow. To achieve this, chemical particles are introduced, or seeded, into these clouds. Snowy Hydro Limited (SHL) uses silver iodide as the seeding particle in the Snowy Mountains. Silver iodide has physical properties very similar to natural ice crystals. In addition, silver iodide is practically insoluble in water, tends not to dissociate to its component ions of silver and iodine, and does not become biologically available in the environment. Instead, it remains as a solid in soils and sediments.

During cloud seeding operations, the seeded silver iodide particles combine with naturally occurring supercooled water droplets in the clouds to form ice crystals. These crystals then grow until they become too heavy to stay within the cloud and fall as snow.

To seed the clouds, ground based generators are arranged along the western side of the Snowy Mountain range. The generators are able to disperse minute quantities of the seeding agent into winter storm clouds as they pass across the range. Cloud seeding operations only target cloud systems travelling from west to east and when temperatures guarantee that precipitation will fall as snow above 1400 metres.

SHL has been conducting a winter cloud seeding trial in the NSW Snowy Mountains since 2004. Independent evaluation of the trial indicates that snowfall can be increased by an annual average of 14% through cloud seeding. Environmental monitoring has to date not detected any significant adverse environmental impacts. The 2022 cloud seeding operations comprised 57 hours and 6 minutes of cloud seeding between 31 May 2022 and 15 August 2022. Approximately 19.1kg of silver iodide was dispersed during these operations, covering a target area about 2,110 square kilometres.

Under the Snowy Mountains Cloud Seeding Act 2004 (the Act), cloud seeding operations may only occur in accordance with an Environmental Management Plan that has been jointly approved by the relevant Ministers. The current Environmental Management Plan was approved by the relevant Ministers on 28 June 2018 following the five yearly review as required under the Act.

The Act requires that SHL provide an annual report to the NSW Environment Protection Authority (EPA) and the relevant Ministers by 31 March, detailing its compliance with the Environmental Management Plan and the results of any research and monitoring into the impact of cloud seeding operations on the environment. The EPA is required to review this report and convey its findings, along with any recommendations, to the Board of the EPA and the relevant Ministers.

Review and findings

The EPA has undertaken its review of SHL’s Annual Compliance Report (the 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 Department of Planning and Environment’s (DPE) 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.

Findings

The review of the 2022 Annual Compliance report found that

SHL has complied with all of its obligations as outlined in the Act. SHL complied with all its obligations within the Environmental Management Plan.
There were two minor incidents which resulted in the spillage of antifreeze and effluent onto the road between Spencers Creek to Guthega Power Station in October 2022, and a spill of a small quantity of silver iodide from a generator trailer in October 2022. No material harm occurred during either incident and corrective actions were implemented to prevent a recurrence. There were no other accidents or breakdowns to report that resulted in a spill 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.
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.
No modifications or new facilities for cloud seeding operations were installed.

Discussion

During 2022 cloud seeding operations, SHL dispersed approximately 19.1 kilograms of the approved seeding agent, silver iodide, into suitable storm systems. Weather conditions suitable for seeding in the Snowy Mountains during the 2022 period resulted in 57 hours of cloud seeding events, and a decrease of 16 hours on the previous year. Consequently, this resulted in a decrease of silver iodine being used, with 3.8 kilograms less than in the previous year.

During the 2022 cloud seeding season, there were no new operations involving land-based methods of discharge of seeding or tracing agent within any area of land. SHL advised that a small quantity (1-2 litres) of antifreeze and effluent had escaped the environmental controls and spilt onto the road between Spencers Creek to Guthega Power Station during transport in October 2022. In the same month, a small quantity (50-100mL) of cloud seeding solution (silver iodide) had escaped the EMP controls. SHL advised that most of the cloud seeding solution evaporated immediately with the remaining solution spilt onto the generator trailer. SHL assure that no material environmental harm was caused and corrective actions were put in place to prevent recurrence for both incidents.

The EMP 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 2019, the EMP’s prescribed five year interval between environmental monitoring programs was found to be appropriate.

Given this, in 2022 potable water was the only matrix sampled. The Annual Compliance Report indicated that 2022 potable water samples were comparable to those from previous years.

However, silver concentrations have increased since 2013 but remain several orders of magnitude below relevant guideline values. Analysis of silver concentrations from samples collected through the environmental monitoring program prior to the commencement of cloud seeding in 2004 through to 2022 showed no evidence that cloud seeding has contributed to increased levels of silver in any area or in any environmental matrix monitored. Analyses of data collected following the 2018 season has shown no evidence of any difference over time in the impairment of the macroinvertebrate assemblages. Macroinvertebrate sampling will take place after the 2023 cloud seeding season in accordance with the EMP.

SHL advised that there have been continued elevated levels of silver readings at the intermediate potable water site due to sediment contamination in the tank. While these results are several orders of magnitude below trigger values, SHL have requested that the site is removed from the potable water sampling program on the basis that it is not used for potable water consumption and contains high levels of sediment contamination. A proposal has been made by SHL to the EPA in the 2023 review of the EMP. DPE has agreed that the silver concentration measured at the intermediate potable water site is bound in the particulate phase, though recommended that further information regarding the use of water from the intermediate site be sought before a decision is made to remove the site from the sampling program. DPE further recommended that SHL provide clarity in their report about the location of the different sampling sites to allow for a better spatial assessment of the provided data. Both of these recommendations and the proposal by SHL will be managed through the 2023 review of the EMP.

Internal audits of cloud seeding sites were undertaken by Snowy Hydro personnel with NPWS, although no site visits were undertaken by NPWS in the 2022 reporting period. NPWS advised access issues identified during the 2020-post season site audit have been rectified with the remaining metal plates scheduled for removal prior to the 2023 winter season. NPWS requested that SHL continue its site inspection and auditing process and requested reports of any significant issues or change.

SHL reported that there was no new infrastructure established or decommissioned during the reporting period, no major visual modifications made to existing infrastructure and no accidents or breakdowns to report that resulted in spillage of cloud seeding agents or fuel, or failure of any of the controls specified in the EMP. No current or emerging issues were formally raised by stakeholders for the 2022 cloud seeding season. Mechanisms within the EMP allow relevant agencies of the Minister for the Environment to request consideration by SHL of emerging environmental issues between each five-yearly review.

Conclusions and recommendations

After reviewing the SHL 2022 Annual Compliance Report and SHL on-ground operations, the EPA concludes that

SHL has complied with all of its obligations as detailed in the Act
SHL has complied with all of its obligations as detailed in the Environmental Management Plan for cloud seeding operations approved by the relevant Ministers on 28 June 2018.
SHL has complied with all of its obligations as detailed in the Protection of the Environment Operations Act 1997
Analysis of potable water sampling carried out during the 2022 cloud seeding season showed silver concentrations remain several orders of magnitude below relevant guideline values.

It is recommended that

Monitoring be continued as per the schedule of the EMP, and data compared over time to identify trends
Monitoring at all potable water tanks as per the schedule of the EMP, noting that the proposal to remove the intermediate sampling site will be considered in the 2023 review of the EMP
Future reviews are also undertaken in consultation with input from partner agencies of the NPWS and DPE
SHL continues to pursue research opportunities on the cloud seeding operations in the Snowy Mountains
The outcomes of this review are communicated to the relevant Ministers.

Compliance with the act

Obligations under the Snowy Mountains Cloud Seeding Act 2004	Compliance status (report reference)
The area to be primarily targeted for the increased precipitation is land within the Snowy water catchment.	(1.4) Addressed
Operations may be carried out only if there is an approved Environmental Management Plan.	(1.1) Addressed
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 All operations carried out within the catchment.
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 Approved land-based aerosol generators
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 Tracing agent not used.
The seeding agent and tracing agent must be discharged by the use of an approved method.	(2.2) Approved Land-based aerosol generators.
The discharge must be carried out in accordance with the conditions (if any) of its approval as a method of discharge.	(2) Addressed
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
SHL 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 No new operations carried out.
SHL 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 No modifications or new installations carried out.
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 No new facilities installed.
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 All land-based generators located in approved areas by NPWS.
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)
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)
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 authorized. Any such scientific assessment must comply with any requirements imposed by the relevant Ministers and notified to SHL.	(N/A)
SHL 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 2023.

Compliance with the EMP

Obligations under the Environmental Management Plan	Compliance status (report reference)
Cloud seeding will not commence if the freezing level over the catchment is greater than 1600 metres and will be suspended or terminated if the freezing level rises above 1600 metres during cloud seeding campaigns.	(3.1) Addressed: Section 3.1 There were no instances where the freezing level rose above 1600 m, therefore additional controls were not triggered. However, one event (Event 3) was suspended shortly after commencement due to wind conditions becoming unsuitable for cloud seeding operations.
Additional controls will be implemented when the freezing level is between 1550 metres and 1600 metres above sea level, including: video monitoring at locations over the target area at approximately 1400 metre elevation to assist in determining that precipitation is not falling as rain when required, undertaking telephone polling to external parties and/or Snowy Hydro Limited personnel within the target area to confirm that precipitation is not falling as rain at approximately 1400 metre elevation.	(3.1) Addressed: Section 3.1 There were no instances where the freezing level was between 1150 - 1600 m.
SHL 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) NPWS advised that vegetation maintenance at Ramshead will be carried out when safe to do so.
The Annual Compliance Report will include: sample locations, data results, evaluation, and adaptive management recommendations for the environmental monitoring program details (including results and evaluation) of any emerging environmental issues< results from meteorological monitoring that can demonstrate SHL’s compliance with the requirement to ensure that increased precipitation falls as snow in areas at an elevation above 1400 metres above sea level results from analyses of downwind precipitation the event time and duration over which cloud seeding occurred any accidents or break downs resulting in spillage of cloud seeding agents, fuel, or failure of controls specified in this Environmental Management Plan the quantity of cloud seeding agents that were released per seeding event per generator	(a – 4.1-4.3) EHG recommends that SHL provides clarity in their report about the location of the different sampling sites to allow for a better spatial assessment of the provided data. (b – 4.4) Addressed: Section 4 No emerging environmental issues (c – 3.1) Addressed: Table 3.1. (d – 3.2) Addressed: Figure 3.1 (e – 2.1) Addressed: Table 2.2 (f – 2.3) Addressed: Section 2.3 (g – 2.2) Addressed: Section 2.3
In addition to the Annual Compliance Report, SHL will also prepare a Cloud Seeding Operations Annual Report which is to be made publicly available on the SHL website within a reasonable timeframe after any recommendations from the Board of the 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 SHL with regards to cloud seeding operations will be resolved in accordance with the following escalation process: use of established paths of communication between SHL and the agency (officer to officer) communication between SHL Executive Officer and agency Department Director communication between the Chief Executives of SHL and the agency.	(2.4) Addressed: Section 2.4 No disputes between NSW Government agencies and SHL. .
SHL will continue to consult with other relevant land managers with respect to vegetation management and site access. SHL 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: Section 1.4 No new infrastructure established, no major visual modifications made to existing infrastructure, and no infrastructure decommissioned.
DPE, the EPA and other identified stakeholders will be advised as soon as practicable following the commencement of, and on the conclusion of cloud seeding campaigns.	(2.1) Addressed DPE and EPA and other identified stakeholders were advised by email.
Existing sites authorised under the Act will be defined by SHL (coordinates and identified on a map) and provided to the Environment and Heritage Group (EHG) 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 EHG and the EPA.	(1.4) Addressed A map of existing sites and details of their coordinates were provided to the EPA and DPE in June 2013. There were no changes to infrastructure in 2022.
Implement all Management Controls (Table 1), 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 removal of infrastructure and rehabilitation of sites.	(2.3) Addressed Infrastructure, including cloud seeding agents and fuel, are managed in accordance with these requirements.
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 cloud seeding operations to continue to monitor downwind precipitation.	(3.2) Addressed: Figure 3.1.
Snow sampling profile sites and preferred access routes will be defined by SHL (coordinates and identified on a map) and provided to EHG and EPA prior to commencement of first annual winter snow sampling operations. Updated coordinates and maps are to be provided to EHG and EPA if sites change.	(1.4) Addressed No snow profile sampling took place in 2022.
Environmental chemistry monitoring
Environmental sampling to be undertaken as per Table 3 in the Environmental Management Plan.	(4.1.2) Addressed: Table 4.1.
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 are collected and processed in accordance with internal work instructions and quality assurance and quality control procedures.
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 No statistical analysis were undertaken for this matrix.
Implementation of steps in decision tools and environmental suspension criteria.	(4.1.1, 4.1.5) Addressed
Macroinvertebrates monitoring
Sampling will be undertaken on a five-year sampling interval, with the first round of sampling to be undertaken following the first year of cloud seeding 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) N/A Macroinvertebrate sampling was not required in 2022.
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/EHG prior to sampling being undertaken.	(4.2) N/A Macroinvertebrate sampling was not required in 2022
The macroinvertebrate sampling program implemented by SHL (and endorsed by EHG) uses the NSW Australian River Assessment System (AUSRIVAS) protocol.	(4.2) N/A Macroinvertebrate sampling was not required in 2022.
Additional monitoring
Relevant agencies of the Minister for the Environment may request consideration by SHL of emerging environmental issues between reviews of this Environmental Management Plan. In order for issues to be considered by SHL, the agency will provide a clear outline of the issue to SHL based on direct evidence or established scientific theory. The agency and SHL will then agree on an appropriate research/monitoring/consultation/reporting regime.	(4.4) N/A No emerging environmental issues were raised with, or identified by, SHL during this reporting period.