Community Meeting Concerning Yamba's Fresh Water Supply & Floodplain Management, 5:30pm Tuesday, 4 February 2025 at Wooli Street Hall, Yamba

 

Public Notice

YAMBA COMMUNITY MEETING

Hosted by Yamba CAN Inc

TOPIC

YAMBA WATER SUPPLY

AND

FLOODPLAIN MANAGEMENT

WHERE & WHEN: Wooli Street Hall, (Wooli Street & Public Library, Yamba Road vehicle entrances) Tuesday 4 February at 5.30pm

PRESENTATION BY: Mr Greg Mashiah, Manager Technical Services, Clarence Valley Council, with responsibilities including delivery of major water infrastructure and sewer projects

Given the situation we are facing as a community, with the recent influx of large residential developments and proposed population growth in Yamba and the Lower Clarence, we feel these are matters of immense importance.

Residents need to be fully informed about the current status and future plans for water quality, supply, infrastructure and emergency management.

Information will be presented about local flood data, (how to interpret it as it affects you), stormwater and floodplain management.

The presentation will be followed by a designated Q&A session.

Community members have informed Yamba CAN they are especially interested in an updated status report on the Rushforth Road Water Filtration Plan project that is currently under review.

It appears many people in our community do not have a good understanding of the process involved in the CVC water supply network from the Nymboida River and Shannon Creek Dam via the Rushforth Road Water Treatment Plant and reservoirs at Maclean and Yamba to end users in Yamba and elsewhere throughout the Valley.

There are a number of issues of ongoing concern in respect of catchment management, water quality and security of supply. There are also some quite complex contractual arrangements between CVC and City of Coffs Harbour as regards sharing of responsibilities for water and infrastructure between the two LGAs. Huge amounts of investment will be needed to fund ongoing maintenance and necessary infrastructure improvements.

How much does/will this cost? What provision has CVC made regarding budgeting and reserves for the necessary works? Where is the money coming from? What is the estimated time for completion?

Chairperson

Yamba Community Action Network Inc

yambacan@gmail.com

NSW landholders can now lawfully take up to 100,000 litres of surface/ground water each year and store it in a tank or dam for future firefighting purposes.

Commonsense approach to bushfire preparedness

Published: 13 January 2025

Released by: Minister for Emergency Services, Minister for Water

The Minns Labor Government is reducing red tape which has in practice stifled farmers’ ability to fight fires on their own property.

During a fire emergency, a landholder can now take water from surface water and groundwater sources on their land without needing to have a water licence and water use approval. This includes streams, creeks and rivers abutting the boundary.

This commonsense exemption has been made via amendments to the Water Management (General) Regulation 2018.

The water can be used by landholders on their property and adjacent land to fight fires. It can also be used for training and controlled burning when it is carried out by or under the authority of a firefighting agency such as the NSW Rural Fire Service (RFS), and for the testing and maintenance of firefighting equipment.

Landholders who wish to prepare for the threat of bushfires can now also lawfully take water and store it in a tank or dam for future firefighting purposes. The maximum volume for each property is 100,000 litres (0.1 ML) per year.

The NSW Government will carry out targeted periodic surveys of landholders to understand how the exemption is being used and to identify the extent and scale of water use.

While landholders are not required to submit reports, they are encouraged to log the volume of water they take under the exemption, for their own records.

Find further information on the exemptions.

Acting Minister for Water Jodie Harrison said:

“Rules to protect the state’s water security are important – but the fact is, when there is a fire, no one should need to stop and think if they are allowed to access water to keep themselves and their property safe.

“This is a common-sense decision, and it is great to see these amendments now in place in time for summer. When fire threatens life and property, landholders need fast and easy access to water to protect their properties and themselves.

“These changes make it easier and cheaper for farmers and property owners to access water to prepare for and respond to emergency fire situations.”

Minister for Emergency Services Jihad Dib said:

“When it comes to emergencies, landholders can play an important role in bushfire response, and this change further empowers them to act when their properties are under threat.”

“The NSW Government has been proactive in finding common sense ways to make it easier for landholders to fight fires on their properties, which also includes a trial to make it easier for farmers to keep firefighting vehicles on their properties.”

¬¬¬¬¬¬¬¬¬¬¬¬¬

What are the new rules?

The exemptions cover specific uses of water:

• to prepare for and fight fires to protect life and property, and

• to take and store water (e.g. in a tank or dam) for future fire fighting needs. Water taken and stored is subject to a 100,000-litre limit per fiscal year.

The exemptions also support fire preparedness activities such as training and controlled burning (by or under the authority of a fire fighting authority), maintenance of fire fighting equipment, and wetting down buildings and land surrounding buildings whenever a fire is threatening a property. 

In 2025 New South Wales is still dancing around the question of post-mining land rehabilitation

"I don’t think I'd even let my enemy drink from that because I think they would die such a horrible death."

[Assoc. Professor Ian Wright, Western Sydney University, 2024]

https://youtu.be/GL9hr5fClGo?si=Z1zsTlsKLoBvt55U

On 14 May 2024 the NSW Parliament Upper House Standing Committee on State Development established the Inquiry into the beneficial and productive post-mining land use, to inquire into and report on beneficial and productive post-mining land use.

Terms of reference can be found at:

https://www.parliament.nsw.gov.au/lcdocs/inquiries/3046/Terms%20of%20reference%20-%20Beneficial%20and%20productive%20post-mining%20land%20use%20-%20Updated%2012%20December%202024.pdf

There is no reporting date listed for this particular Inquiry.

After a 53 day submission period in which 78 submissions were received, the Inquiry held 5 hearings commencing on 5 August 2024 and ending on 17 December 2024. Videos of all 6 hearings can be found at:

https://www.youtube.com/playlist?list=PLb7SKvfgKNwZpuRxxsmOhEvvnKeAXKzTk

Commencing on 2 July 2024 the Inquiry received 40 documents to assist in its deliberations.

In August 2024 the Standing Committee on State Development visited former mining sites in Lake Macquarie, Cessnock, Maitland and the Upper Hunter and held two public hearings (Muswellbrook & Singleton).

SOME BACKGROUND ON FORMER MINING SITES

ABC News, 16 February 2017:

More than 60,000 mines have been abandoned across Australia, according to a report that raises concerns about how land rehabilitation is managed as the mining boom ends.

Key points:

Australia Institute report finds lack of reliable data on Australia's mining activity

Research finds more than 60,000 abandoned mines across Australia

Only a handful of mines have ever been fully rehabilitated

Report raises concerns over how land rehabilitation is managed

The Australia Institute research, obtained exclusively by Lateline, said there were few reliable statistics on the state of Australia's mines and there was evidence that only a handful had ever been fully rehabilitated.

State government agencies were only able to name one example of a mine that had been fully rehabilitated and relinquished in the past 10 years — the New Wallsend coal mine in New South Wales.

Some of the abandoned mines date back to gold-rush days and the 60,000 figure includes thousands of mine "features", such as tailings dams and old mine shafts.

The Australia Institute said it was difficult to obtain basic statistics on the number of operating mines across the country, putting the figure between 460 and 2,944.

The Institute said it was even harder to get data on mines that had suspended operations or were undergoing rehabilitation.

"What is certain is [mine abandonment] is not a practice limited to distant history," the report said.

"As the owners of the largest mines come under financial pressure, close attention needs to be paid to the ongoing phenomenon of mine abandonment in Australia.".....

In New South Wales, approval has been granted for 45 massive coal pits, or voids, to be left after mining finishes. [my yellow highlighting]

Twelve of those voids are around Muswellbrook in the Upper Hunter and the biggest is at BHP Billiton's Mount Arthur mine.

It is 4.5 kilometres long and 1.5 kilometres wide. BHP would not provide details on its depth....

NORTHERN NSW BACKGROUND

North Coast Voices, "Deputy Leader of Opposition Business in the House of Representatives & MP for Cowper betrays the Clarence, 28 September 2011, excerpt:

....ongoing antimony contamination of water bodies and land protected by Environmental Planning Instruments is not unknown from previous mining ventures in northern NSW.

The Macleay Argus 2 September 2011:

HIGHER than average levels of heavy metals have been recorded in the Macleay River at Bellbrook after a dam overflowed at a gold and antimony mine near Armidale.

NSW Health and Kempsey Shire Council said higher than normal levels of metals including arsenic, zinc and copper had been detected in the waters of the Macleay River.

But both organisations said the concentration of the heavy metals was not high enough to warrant concern to people.

As a precaution NSW Health has contacted residents in the upper Macleay to inform them not to drink water from the river unless it has been processed through the Bellbrook water treatment plant.

Council has undertaken further testing to determine whether the contamination has spread beyond Bellbrook….

The Office of Heritage and Environment (OHE) reported the breach occurred on Tuesday when there was a release of material from a sediment erosion control dam at the Hillgrove antimony and gold mine.

"The mine is currently not operating but is in 'care and maintenance' mode," a spokeswoman said.

"The spill occurred after continued wet weather produced excess stormwater which exceeded the amount of water that could be stored in the dam resulting in the spill - when the mine is operating the stormwater would normally have been used for mineral processing."

NSW Office of Environment and Heritage Media Release 5 July 2010:

Straits (Hillgrove) Gold Pty Limited has been fined $50,000 and ordered to pay costs of $24,000 in the NSW Land and Environment Court today after being found guilty of polluting waters.

Straits pleaded guilty to the charge; pollution of water under the Protection of the Environment Operations Act.

The company 'Straits' conducts gold and antimony mining activities at the Hillgrove Mine, near Armidale in NSW.

In sentencing today, Justice Biscoe convicted and fined Straits $50,000 and ordered it to pay the prosecutor's legal costs of $24,000.

The court heard that in April 2009 a protective bund at the premises had been lowered to allow access for an electrical contractor. When a screening device used in the mine became blocked and 'slimes' discharged and spilled into the bunded area, it then overflowed the bund and discharged into the local environment.

The spill, of up to 3000 litres of 'slimes,' contained antimony, arsenic and lead and is toxic to some aquatic life.

Department of Environment, Climate Change and Water (DECCW), Director General, Lisa Corbyn said the penalty provided a timely reminder to companies that they must ensure measures are in place to contain pollution.

"This case highlights the potential for serious damage to occur and highlights the importance of companies having safeguards and operating procedures in place to control pollution at all times. Carelessness meant that simple containment structures which could have prevented the spill from leaving the mine site were not in place. Fortunately the environmental harm from this particular spill was low.

"Importantly, the company did report the spill to the DECCW Environment Line and cooperated with the DECCW officers throughout the investigation."

Anyone who sees pollution is urged to contact the Environment line on 131 555.

Bellingen Shire Council State of the Environment Report 2009-2010:

Urunga antimony processing site

A seriously contaminated site has been identified at Urunga, Portions 138 & 169 Parish of Newry. Contamination also affects adjacent Crown Land and a SEPP 14 wetland. The site was previously used for antimony ore processing, since abandoned without rehabilitation of the site. DECCW have undertaken an investigation of the site and researched remediation options.

General

Council maintains records of properties known to be affected by contamination. Council must consider the requirements of the Contaminated Land Management Act 1997 and State Environmental Planning Policy 55 – Remediation of Land in assessing proposed changes to the use of land.

Antimony and arsenic dispersion in the Macleay River catchment, New South Wales: a study of the environmental geochemical consequences, February 2007:

A baseline geochemical study of stream sediments and waters of the Macleay River catchment in northeastern New South Wales indicates that although most of the catchment is unaffected by anthropogenic or natural inputs of heavy metals and metalloids, the Bakers Creek - trunk Macleay-floodplain system has been strongly affected by mining-derived Sb and As. The dispersion train from the Hillgrove Sb - Au mining area to the Pacific Ocean is over 300 km in length. Ore and mineralised altered rock from Hillgrove contains vein, breccia-hosted and disseminated stibnite, arsenopyrite, pyrite and traces of gold. Historic (pre-1970) mine-waste disposal practices have resulted in high to extreme contamination of stream sediments and waters by Sb and As for ∼50 km downstream, with high Au values in the sediments…..

Estimates of sediment migration rates and amounts of Sb and As transported in suspension and solution imply that the catchment contamination will be long-term (centuries to millennia) such that environmental effects need to be ascertained and management strategies implemented…

[Ashley, P. M.; Graham, B. P.; Tighe, M. K.; Wolfenden, B. J in Australian Journal of Earth Sciences, Volume 54, Number 1, February 2007 , pp. 83-103(21)]

North Coast Voices, "NSW North Coast antimony contamination makes it onto national television", 25 October 2011, excerpt:

The Sydney Morning Herald also addressed the issue of historic and recent contamination from the Hillgrove antimony mine:

A PLUME of toxic pollution from an old antimony mine appears to have killed fish for dozens of kilometres along the Macleay River in northern NSW.....

a study published by the CSIRO in 2009 described the waterways near the mothballed mine as ''highly contaminated'' and estimated about 7000 tonnes of waste had accumulated along the bed of the Macleay River.

Water tests have shown antimony levels at 250 times background levels, with high levels detected along the river to the coast at Urunga, where the mineral was once processed for export. 

Clarence Valley State of Play: as the first day of Summer draws closer memories of past summers surface

 

Right now the Clarence River flow at Newbold Crossing is registering in the >80% stream flow percentile, the Shannon Creek side dam is at 99% capacity and soil moisture is for the most part within acceptable limits across the Clarence Valley which is classified 100% non-drought.

However, the Australian Summer officially begins on 1 December 2024 and air temperatures and water evaporation rates are bound to rise.

So how is the New South Wales Combined Drought Indicator (CDI) Map likely to look come December?

Where we are going?

NSW Dept. of Primary Industries and Regional Development, Climate Branch, Drought Forecasting, 17 November 2022:

NOTE: The DPIRD drought forecast for NSW presents the ‘Most Likely’ Combined Drought Indicator (CDI) category for the forecast period. The Most Likely CDI category is determined by identifying the 'mode' of the CDI. The mode is the category that appears most frequently across all possible forecast outcomes in the ensemble run. It is the most common prediction for drought conditions in the forecast period based on the model's simulations.

Where have we been along the Clarence Valley drought history continuum, 20 November 2019 to 9 October 2024?

Click on graphs to enlarge

Fine Flower & environs

Heifer Station & environs

Grafton & environs

Maclean & environs

Yamba

*All maps & graphs were created on 17.11.24 using interactive tools created by NSW Dept. of Primary Industries and Regional Development, Climate Branch

Combined Drought Indicators

The NSW Combined Drought Indicator (CDI) includes four indicators for rainfall, soil moisture, plant growth and drought direction which, used together, can indicate the five phases of drought.

Rainfall Index (RI)

The RI is the percentile rank of rainfall aggregated over 12 months. The ranking is made using a 30 year (1980-2010) baseline which captures recent big shifts in climate variability, and factors in climate change. This provides an index between 0 and 100 where values approaching 0 are close to driest, and those approaching 100 close to the wettest, for any given region. Percentile-based indices like the RI have a uniform distribution regardless of their climatic setting, which is an attractive feature in NSW given the presence of rangeland, temperate and sub-tropical climates which have skewed, normal and log-normal rainfall distributions.

Soil Water Index (SWI)

The SI is calculated using the same procedure as the RI, but uses a soil moisture field derived from the DPI AgriModTM soil water balance. Plant available soil water from layer one (0-10cm) and layer two (11-45 cm), the assumed maximum rooting zone, are aggregated and used to calculate the SWI. Similar to the RI, the SWI is an index between 0 and 100. In most districts of NSW a value of 0 means there is no plant available water held in the profile. The SWI is a hydrological index, but its configuration means that it is more useful as an indicator of conditions for dryland than irrigated agriculture.

Plant Growth Index (PGI)

The PGI is calculated using the same general procedure as the RI, using the output from DPI’s crop and pasture models. Crop stress and pasture growth data are taken from DPI AgriModTM, and the percentile rank calculated for each day. If the predominant land use in a given area is cropping, the PGI uses the crop-derived data, otherwise it uses the pasture growth indicator. The PGI is an agronomic drought index which is not only sensitive to moisture but also temperature variation and seasonal events such as frost. It is important to note that the PGI tracks the influence of climate on production potential across broad areas only. This provides a regional indicator of conditions. In the paddock, management decisions like fertiliser application and timing, sowing times and stocking rates drive outcomes on the ground, and in-field conditions can be above or below the regional indicator reported by EDIS.

BACKGROUND

The main water supply (other than the village systems of Wooli and Minnie Water) in the Clarence Valley is sourced from the Nymboida River, flowing through a section of the wider Clarence River catchment area.

At this time of year the Clarence Valley urban water supply is drawing around 14.26ML/per day from the river weir.

The Nymboida River also gravity feeds water to Shannon Creek Dam when required and, if the Nymboida river flow is too low (less than 225 Megalitres a day) or turbid post-flood, the Clarence Valley's principal urban areas receive water sourced from the off-stream storage at Shannon Creek.

Overall, Shannon Creek Dam is used to supply the Clarence Valley’s water about 5% of the time. Right now this dam is at 99% capacity.

This scenario is complicated by the fact that historically the Clarence Valley also supplies water out of the catchment to Coffs Harbour City local government area and this draw on catchment water is constant and always exceeding an optimal sustainability level for average daily drawn down.

Byron Shire Council being less than transparent over a proposal to cut more than 30 shire residents off from a reliable town water supply as a cost cutting measure

 

Echo, 10 July 2024, Residents face being cut from Mullum’s water, excerpt:

More than 30 affected residents say their properties are at the bottom of Wilsons Creek and some areas of Mullumbimby Creek, and they were only told they will likely be cut off from town water after questioning Council staff about the Mullumbimby Water Supply Strategy.

Spokesperson for the Wilsons Water Rights Action Group (WWR) Mel Macpherson said she was shocked to find out from a neighbour about Council’s plans to remove their connection to town water without any direct written or verbal communication.

‘One would think the appropriate action for Byron Shire Council would be to talk to us individually, and let us know that their preferred water strategy means cutting us off – for the 30 residents this has drastic ramifications, we have a right to know.

‘I honestly feel the communication from Byron Council has not been acceptable at all. This decision directly affects our health, businesses, infrastructure and property values. Relying on us to scan social media or listen to the radio to find out we are getting cut off has left me baffled.

‘I only found out because my neighbour who has lived here for 90 years told me, and knew the history of the weir and local infrastructure, and noticed this in the water strategy plans......

Echo, Letters to the Editor, Losing town water access,13 July 2024:

I grew up and live in Mullumbimby, and I know locals have a strong opinion about the Byron Shire Council. I had always given them the benefit of the doubt – as it’s not an easy job. But last week I changed my mind.

Our neighbour, Ray Musgrave, alerted us and other neighbours we’d be losing town water access on our properties. At first, I thought this was simply the Mullum rumour mill, but I called around at Council and found out it was true. Without any doorknocks, phone calls, or letters, we found out dozens of residents at the bottom of Wilsons Creek, including us, would lose town water access if Mullum is connected to Rous water.

While this decision has not been officially made by Council – yet – we all know it is the likely decision. I work in media and communications, sometimes as a consultant for state and federal government, and I’ll admit that tactics are sometimes a little underhanded, but, when it comes to infrastructure and impacting households like this, there would always be doorknocks to every home at a minimum in the communications plan. So, I’m simply shocked at these sneaky tactics by our local council.

Luckily, we have all been neighbours for decades or generations here and were able to quickly agree to work together to try and save our town water. Wish us luck!

Casey Fung, Wilsons Creek

According to the Byron Shire Council website as of 15 July 2024:

Regional water supply

All urban areas in Byron Shire are supplied water from Rocky Creek Dam, which is managed by Rous County Council.

Mullumbimby is supplied from Council's Lavertys Gap Weir.

Rous County Council supplies drinking water to seven reservoirs in the Byron Shire Council from the Nightcap Water Treatment Plant.

Under the Water Supply Agreement, we are responsible for maintaining water quality in the reservoirs and reticulation system......

The Mullumbimby Water Treatment Plant provides treated, filtered, and disinfected drinking water to Mullumbimby.

The drinking water supply is sourced from Wilsons Creek via the Lavertys Gap Weir.

Water flows to the plant by gravity through a heritage-listed race, via a mountain tunnel.

Council documents indicate approximately 13 properties along Wilsons Creek Road are connected to the trunk main from the water treatment plant.

The preferred option of council staff coincides with advice contained in a Hydrosphere Consulting Pty Ltd report (updated May 2024) which clearly stated in 12.4 Option 4 - Full Connection to RCC Regional Supply:

The customers along the Wilsons Creek Road trunk main would not be serviced with this arrangement.

In an alternative scenario within Option 4 Hydro Consulting suggested an Option 4B - emergency connection to regional supply:

As an alternative, the existing RCC emergency supply pipeline could be extended to service the remaining areas of Mullumbimby as an emergency supply only. BSC would then retain Lavertys Gap Weir and WTP as the normal supply regime with future augmentation with another raw water supply source. The customers along the Wilsons Creek Road trunk main would still be serviced by the weir supply and WTP if there was sufficient water in the weir storage. [my yellow highlighting]

However, Byron Shire Council on its public exhibition webpage did not immediately draw attention to the fact that some properties may lose a reliable long-term connection to town water. 

In the first instance it presented the case thus, with the fate of Wilsons Creek Road concealed in webpage links:

Mullumbimby’s water supply scenarios

The consultant’s report short-listed four water supply scenarios, summarised below.

Each scenario has associated benefits and costs.

Council’s engineering staff recommend Scenario 3 – permanent connection to the Rous County Council water supply.

For each scenario, some factors remain the same, including:

• continued use of the weir and Water Treatment Plant (WTP) in the short term

• short-term WTP upgrades to ensure consistent, safe water supply

• extension of the Rous County Council emergency bulk water supply connection to all of Mullumbimby.

Indeed within its boasting about the benefits of what it calls "Scenario 3" it is clear that the potential loss of a long-term reliable town water supply for 30 shire residents & ratepayers is a short-term cost cutting measure.

Scenario 3 – Full connection to Rous County Council

Rous County Council is the regional water supply authority for the Byron Shire, with the exception of Mullumbimby.

Rous also supplies:

• Ballina Shire

• Lismore Shire

• Richmond Valley Shire.

Permanent connection to the Rous regional water supply would mean that water is no longer sourced from Lavertys Gap weir and the Mullumbimby water treatment plant (WTP).

As a result, there would be no need to build a new WTP at Mullumbimby.

Permanent, full connection to the regional water supply is the option recommended by the consultants and Byron Shire Council staff based on the environmental, economic and social assessment.

Benefits of full connection

Connecting to the regional supply has significant benefits over local supply scenarios. [my yellow highlighting]

Full connection offers:

• minimal environmental impact

• lower energy consumption

• reduced infrastructure modifications.

There are significant capital cost savings in avoiding the need to replace the WTP and upgrade the weir supply in addition to constructing new infrastructure. However, the ongoing costs of a regional supply are higher than local scenarios. [my yellow highlighting]

Permanent connection to the regional supply means Mullumbimby’s long-term water security is determined by Rous County Council's bulk supply system, as is the case for the rest of Byron Shire.

Byron Shire Council is scheduled to decide on its water supply strategy at its August monthly meeting.

Yet another Clarence Valley development application with wet feet?

 

MASTER PLAN
DA 2023/0711
Click on all images to enlarge

Clarence Valley Independent, 20 December 2023:

A development application DA 2023/0711 for a $6.65 million 95 lot manufactured home estate at South Grafton is currently being assessed by Clarence Valley Council and submissions from the public are invited.

The DA lodged by John Codling is for the demolition of existing buildings at 252 to 298 Rushforth Road and construction of a 95 dwelling manufactured home estate, a community building, a 25m by 10m swimming pool, children’s play area, community gardens, recreation areas and community title subdivision.

The Statement of Environmental Effects SEE, lodged with the DA states the 95 home manufactured housing estate will take up 8.57 hectares of the 11.54-hectare property, with proposed residential sites varying from 282 square metres to 450 square metres.

The Manufactured Home estate will be located on the southern and eastern portions of the property, with the northern and western areas remaining unimpacted by construction.

“The proposed large community clubhouse, centrally located at the entrance to the development, will act as an indoor and outdoor meeting place for residents of the estate and their visitors,” the SEE states.

“The proposed dwelling sites and community facilities will be set in a landscaped environment supported by recreational facilities.”......

Sounds like low income retirees heaven, doesn't it?

Until one realises that an existing wide drainage channel easement dissects the planned manufactured home estate and discharges into what appears to be marshland and creek. Which sets the mind a-wondering.

From there it is easy to discover that the entire manufactured home estate on that lot will be directly in the path of the maximum possible Clarence River flood (based on probable maximum precipitation) according to Clarence Valley Council 2022 flood modelling.

Clarence River very dark blue, 1 in 100 probability in any given year for a flood event is coloured darker blue and, the full range of a maximum probability flood coloured light blue with est. 11.5 ha DA site in dark red.

IMAGE: https://maps.clarence.nsw.gov.au/intramaps910/

In addition the "Stormwater Management Plan & Preliminary Flood Assessment" (17 October 2023) at Page 10 supports this view and adds another dimension:

2. The subject site is subject to Clarence River flooding during an ‘extreme event’. This is limited to the northeastern portion of the site (Figure 4).....

5. The entire site is subject to flooding during a Probable Maximum Flood (PMF) event (Figure 8). Depth and velocity information is not available.

6. Site inundation due to 1:100 storm event runoff from the Rushforth Reservoir (Figure 9) is similar but of a lesser extent than what is mapped as fluvial inundation (Figure 5). Nine lots are affected by shallow (<0.2m) inundation (Figure 11).

7. A Rushforth Reservoir dam break would inundated a large component of the northeastern site precinct (Figure 10). The inundation depth in the northeastern part of the site where the lots are is generally below 0.5 metres (Figure 12), but it increases to 0.8 metres along the eastern site boundary (past the lots).

The developer cannot fail to be aware that the site will experience everything from episodic, low-level nuisance flooding from the creek to a probable maximum full inundation from the river 13.6-13.7m in height potentially sending on a conservative calculation 0.6-3.8m or somewhere between 2-12 feet of rushing water though the manufactured home estate.

Bottom line is that the next time climate change throws a record breaking Clarence River flood at valley communities, South Grafton will possibly have another 190+ people to evacuate to higher ground - as is advised at Page 18 of the developer's document "Stormwater Management Plan & Preliminary Flood Assessment". 

Not sounding quite as attractive now, does it?

SEE FULL DETAILS AT: https://cvc-web.t1cloud.com/T1PRDefault/WebApps/eProperty/P1/eTrack/eTrackApplicationDetails.aspx?r=CVC.P1.WEBGUEST&f=%24P1.ETR.APPDET.VIW&ApplicationId=DA2023%2f0711