Annual Operations Plan Peel Valley 2019-20 Acronym Definition
AWD Available Water Determination Contents BLR Basic Landholder Rights BoM Bureau of Meteorology
CWAP Critical Water Advisory Panel Introduction 2 CWTAG Critical Water Technical The Peel River system 2 Advisory Group Regulated and unregulated system flow trends 3 DPI CDI Department of Primary Rainfall trends 3 Industries - Combined Water users in the valley 4 Drought Indicator
DPIE EES Department of Planning, Water availability 6 Industry and Environment Current drought conditions 7 - Environment, Energy & Chaffey Dam storage 7 Science
Resource assessment 8 DPI Department of Primary Fisheries Industries - Fisheries Water resource forecast 9 DPIE Department of Planning, Chaffey Dam - past 24 month rainfall 9 Water Industry and Environment - Chaffey Dam - past 24 month inflows/statistical inflows 10 Water Weather forecast - 3 month BoM forecast 10 FSL Full Supply Level Chaffey storage forecast 11 HS High Security
IRG Incident Response Guide Annual operations 12 Deliverability 12 ISEPP Infrastructure State Environmental Planning Scenarios 13 Policy Deliverability of ordered water 14 LGA Local Government Areas
Critical dates 15 ROSCCo River Operations Stakeholder Consultation Committee
Projects 15 D&S Domestic and Stock vTAG Valley Technical Advisory Group Introduction
This plan outlines WaterNSW’s response to the drought in the Peel Valley including:
• identification of critical dates • our operational response • potential projects to mitigate the impact of the drought on customers and communities within the valley.
The NSW Department of Planning, Industry and Environment’s Extreme Events Policy and Incident Response Guides outline 4 stages of drought. The Peel Regulated River system is assessed to be in stage 4, which is categorised as ‘severe drought/water shortage’.
The Peel River system
The Peel River flows from its eastern source in the Great Dividing Range, through the Peel Valley in a westerly direction to its confluence with the Namoi River, approximately 40 kilometres downstream of Tamworth. Multiple tributaries enter the Peel River as it travels through the valley including:
• Duncans Creek • Moore Creek • Dungowan Creek • Timbumburi Creek • Cockburn River • Tangarratta Creek • Goonoo Goonoo Creek • Attunga Creek.
N WALGET WEIR THE CUTTING BA LA A R PI GUNIDGERA A Key TH N REGULATOR RIVEWALGETT CR Major towns E BURREN EK ON MOLLEE MANILLA RIVER BARW JUNCTION WEE WAA Major dams RIVER WEIR NARRABRI Dams BARRABA BA K EEK (not waterNSW) CR E ULES CR SPLIT ROCK RA E MA E DINE GUNIDGERA DAM E NA K CREEK CR River system BOGGABRI MO MANILLA I RIVE Regulated river HENA GUNIDGERA WEIR R BO GUNNEDAH River CO TAMWORTH catchment Namoi CARROLL
XS
DUNGOWAN River CR catchment Peel WOOLOMIN
NAMOI RIVER E CHAFFEY E DAM Regulated weirs K EEPIT NUNDLE K QUIRINDI Unregulated weirs DAM PEEL RIVER WALLAMORE WEIR DUNGOWAN DAM PARADISE WEIR CARROLL COCKBURN RIVER WALLAMORE ANABRANCH
DUNGOWAN GOONOO GOONOO CREEK DUNGOWAN CREEK
TAMWORTH WATER SUPPLY CHAFFE Y DUNGOWAN OFFTAKE DAM DAM
NUNDLE
2 Regulated and unregulated system flow trends
Carroll Gap represents the end of the regulated system.
Regulated and unregulated flows from the Peel River at Carroll Gap contribute to an average total annual discharge of 252,900 megalitres (ML). This amount fluctuates significantly over time, which illustrates the significant variability in flows between wet and dry years. Variability in flow levels also occur across the valley and between seasons due to summer being the predominate time for rainfall and irrigation use.
Flows originating from the Cockburn River catchment contribute to approximately 40% of the average annual discharge measured at Carroll Gap. Other significant contributors include Goonoo Goonoo and Dungowan Creeks, both contributing approximately 10% to the average annual discharge. The Peel River above Chaffey Dam is best described as a minor contributor to discharge at Carroll Gap.
Chaffey Dam captures water during times of high flow and releases it when natural Peel River flows are insufficient to meet demands for water. The overall effect of this is to reduce flow variability immediately downstream of the dam.
In addition to the Peel River, the Cockburn River, Goonoo Goonoo Creek and Dungowan Creek exhibit perennial flows in most years. All other creeks and streams within the Peel Valley are less permanent in nature.
Rainfall trends
For the period April 2017 to March 2019, lowest-on-record rainfall was observed over southern inland Queensland and areas of northwestern New South Wales. Over most of this area, rainfall for the period was less than 50% of the 1961–1990 average. Large areas from central to southwestern Queensland, and northcentral and northwestern New South Wales, into northeastern South Australia, have seen rainfall totals between 40% to 60% of this average, implying that nearly one year’s worth of average rainfall has been missed over this two-year period.
The recent dry periods have been especially severe during the cooler months of April to September, an important time for agriculture and the replenishment of surface and groundwater storages across southern Australia. Averaged over the Murray-Darling Basin (MDB), the total rainfall over two consecutive April to September periods was the lowest on record, at 217.5 millimetres (mm). This is around 15% below the previous record, which saw 255.7 mm over the 1940–41 April to September period. It was also the only instance of an April to September rainfall total below 125 mm in two consecutive years.
Rainfall for the combined two-year 2017 and 2018 April to September period was the lowest on record and very much below average (lowest 10% of all such periods) for large parts of southeastern and southwestern Australia. Around 50% of New South Wales was lowest-on-record for these two periods combined.
The winter of 2019 again saw continuing dry conditions, which now means three consecutive winters of below average rainfall.
Over the 24-month period, there has been a large decline in water resources in the northern half of the MDB, including over the Namoi and Upper Macquarie catchments. The Namoi has had the second lowest-on-record rainfall for equivalent 24-month periods, with rainfall around 62% of the 1961–1990 average. Rainfall in the Upper Macquarie catchment is around 71% of the average.
3 Water users in the valley
Basic Land Holder Rights (BLR)
BLR includes water for Domestic and Stock extracted from a water source fronting a landholder’s property, or from any aquifer underlying the land, and for native title rights. (a) 0.82 megalitres per day (ML/day) in the Peel Regulated River water source (b) 1.54 ML/day in the Peel Unregulated River water sources, comprising: (i) 0.04ML/day in the Chaffey Dam water source (ii) 0.39 ML/day in the Goonoo Goonoo Creek water source (iii) 0.22 ML/day in the Upper Peel River tributaries water source (iv) 0.29 ML/day in the Lower Peel River tributaries water source (v) 0.60 ML/day in the Cockburn River water source (c) 0.66 ML/day in the Peel Alluvium water source (d) 11.1 ML/day in the Peel Fractured Rock water source.
Domestic and Stock use
The share components of Domestic and Stock access licences authorised to take water from these water sources are 1,263 megalitres per year (ML/year), distributed as follows: (a) 169 ML/year in the Peel Regulated River water source (b) 209 ML/year in the Peel Unregulated River water sources, comprising: (i) 15.5 ML/year in the Chaffey Dam water source (ii) 28 ML/year in the Goonoo Goonoo Creek water source (iii) 28.5 ML/year in the Upper Peel River tributaries water source (iv) 64 ML/year in the Lower Peel River tributaries water source (v) 73 ML/year in the Cockburn River water source (c) 266 ML/year in the Peel Alluvium water source (d) 619 ML/year in the Peel Fractured Rock water source.
Local water utilities
The share components of local water utility access licences authorised to take water from these water sources are 22,630 ML/year, distributed as follows:
(a) 16,400 ML/year in the Peel Regulated River water source (b) 5,600 ML/year in the Upper Peel River tributaries water source (c) 530 ML/year in the Peel Alluvium water source (d) 100 ML/year in the Peel Fractured Rock water source (e) 0 ML/year in all other water sources.
4 High security
The share components of regulated river (high security) access licences in the Peel Regulated River water source total 804 unit shares.
General security
The share components of regulated river (general security) licences in the Peel Regulated River water source are 29,635 unit shares. While the general gecurity irrigators hold 29,635 unit shares, the average allocation over the last 10 years in the valley is 58%.
Aquifer access licences
The share components of aquifer access licences authorised to take water from these water sources include 28,354 unit shares, distributed as follows: (a) 18,379 unit shares in the Peel Alluvium water source (b) 9,975 unit shares in the Peel Fractured Rock water source (c) 0 unit shares in all other water sources.
Aquifer (general security) access licences
The share components of aquifer (general security) access licences authorised to take water from the Peel Alluvium water source are 32,206 unit shares.
Unregulated river access licences
The share components of unregulated river access licences authorised to take water from these water sources include 11,898 unit shares, distributed as follows:
(a) 384.5 unit shares in the Chaffey Dam water source
(b) 1,033.5 unit shares in the Goonoo Goonoo Creek water source
(c) 3,638 unit shares in the Upper Peel River tributaries water source
(d) 2,477 unit shares in the Lower Peel River tributaries water source
(e) 4,365 unit shares in the Cockburn River water source.
Environmental water
Planned environmental water includes:
• a 5,000 ML environmental contingency allowance (ECA) account
• at least 50% of water above the threshold for access to uncontrolled flows - water originating from tributary inflows to the Peel Regulated River water source
• uncontrolled flows originating from tributary inflows to the Peel Regulated River below the access thresholds, minus any basic landholder rights extraction
• a minimum daily release of 3 ML/day, except when a release greater than 3ML/day is required to meet BLR and access licence extractions, or the ECA.
5 Uncontrolled flows in the Peel Regulated River refer to:
• unregulated inflows that enter the system either downstream of the dam or from dam spills, or
• releases from the dam as stimulus and/or ECA flows. Water originating from tributary inflows and dam spills was historically referred to as off-allocation water, when managed under the Water Act 1912. Under the Water Management Act 2000, these flows can be accessed under Section 85A which allows a water sharing plan to provide for the taking of water from uncontrolled flows, via a regulated river (general security) access licence that has not been credited to an allocation account. This access to uncontrolled flows under section 85A (often referred to as ‘no debit access’) in the Peel Regulated River water source has been established as a substitution type arrangement where uncontrolled flows can substitute for general security allocations. It is this type of access that largely reflects the historical access to off-allocation in the Peel Valley.
Rules for uncontrolled flow access to unregulated inflows:
• All uncontrolled flows that originate from unregulated inflows in the Peel Regulated River, above the following uncontrolled flow access commencement thresholds, will be shared 50:50 between users and the environment.
• When the sum of Available Water Determinations (AWDs) for regulated river (general security) access licences in the Peel Regulated River water source is less than 0.35 ML/unit shares in the water year, then uncontrolled flows: ƈƈ can commence to be taken when the uncontrolled flow in the Peel River at Carroll Gap is equal to or greater than 40 ML/day ƈƈ must cease to be taken within each section of the water source when the uncontrolled flow in the Peel River, at any river gauging station within the respective section, falls below 5 ML/day. • When the sum of AWDs for regulated river (general security) access licences in the Peel Regulated River water source is equal to or greater than 0.35 ML/unit shares in the water year, then uncontrolled flows: ƈƈ can commence to be taken when the uncontrolled flow in the Peel River at Carroll Gap is equal to or greater than 50 ML/day ƈƈ must cease to be taken when the uncontrolled flow in the Peel River at Carroll Gap is less than 50 ML/day.
Water availability
Water allocations in the Peel Regulated River water source for 2019-20, as of 1 July 2019:
• Local water utility and Domestic and Stock water access licence holders received an allocation of 70% of entitlement.
• High security water access licence holders in the Peel Regulated River water source and its sub categories received an allocation of 50% of entitlement.
• General security water access licence holders received an allocation of 0% of entitlement.
• All local water utility and Domestic and Stock water access licence holders in the Peel Unregulated River, Peel Alluvium and Peel Fractured Rock water sources received an allocation of 100% of entitlement.
6 • In the Peel Alluvium water source, aquifer access licence holders received an allocation of 100% of entitlement, while aquifer (general security) access licence holders received an allocation of 51% of entitlement.
• Peel Unregulated River water access licence holders received an allocation of 100% of entitlement.
• Aquifer access licence holders in the Peel Fractured Rock water source received an allocation of 100% of entitlement.
Current drought conditions
The system continues to experience low inflows to both Chaffey Dam and downstream tributaries. Over the last 10 years, good inflows occurred in three years: 2010-11, 2011-12 and 2016-17.
Extremely low inflows also occurred in three years: 2013-14, 2017-18 and 2018-19. The occurrence of two extremely low inflows in consecutive years is rare; two years of below-average winter rainfall had not previously been recorded.
Peel Valley inflows
250,000
200,000
150,000 Inflows (ML) 100,000
50,000
0 2009-10 2010-11 2011-12 2012-13 2013-14 2014-15 2015-16 2016-17 2017-18 2018-19
Chaffey Inflow Downstream Tributaries
The inflows for the 24-months (November 2017 to October 2019) was 6,200 ML. This is 47% of the previous minimum observed 24-month inflow of 13,100 ML.
As of 30 October 2019, Chaffey Dam is at 20,400 ML (19.8% capacity of the total storage volume). Deliveries to town water and Domestic and Stock supplies are being maintained.
Chaffey Dam storage
As a result of the low inflows over the past two years, the volume of water in Chaffey Dam has slowly declined since being full in May 2017. The graph below shows Chaffey Dam’s behavior for the 2019-20 water year, compared to the last four water years, with the capacity expressed in relation to the current (enlarged) Chaffey Dam capacity.
The volume of Chaffey Dam was around 25% at the start of the water year and was drawn down to 20.4% of total capacity at the end of October, which is lowest volume since the 2014-15 water year.
Over the 2018-19 water year, 8,909 ML was supplied to town water and 9,327 ML was provided to general security irrigation.
7 Chaffey Dam storage 120,000
100,000
80,000
60,000
40,000 Storage capacity (ML)
20,000
0 Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
2015/16 2016/17 2017/18 2018/19 2019/20
Resource assessment
The resource assessment is the process of calculating how much water is available based on the rules of the Water Sharing Plan (WSP). This is usually done at the end of the month and when any significant inflow event occurs.
The planning horizon for this resource assessment is 24 months. Taken into consideration is the volume of water held in storage, plus the expected minimum inflows.
As of 1 July 2019, the start of 2019-20 water year, the total amount of water available in Chaffey Dam was 25,700 ML. This limited volume resulted in the following restricted available water determinations:
• general security – 0%
• high security - 50%
• local water utilities - 70%
• Domestic and Stock - 70%
• No carryover is available for general security licence holders in the Peel Valley.
These available water determinations announced on 1 July 2019 remain unchanged.
8 Water resource forecast
Chaffey Dam - past 24-month rainfall
Over the last 24 months, the rainfall across the Peel catchment was the lowest on record. Rainfall was in the range of 600 mm to 1200 mm for the 24-month period. The median annual rainfall across the Peel catchment is 400-1,000 mm per year.
Total NSW rainfall (mm) for 24-months - 1 November 2017 to 31 October 2019
NSW rainfall deciles for 24-months - 1 November 2017 to 31 October 2019
9 Chaffey Dam - past 24-month inflows/statistical inflows
The inflows for last the 24 months were 6,200 ML which is lower than the minimum observed historic flows of 13,100 ML.
Chaffey Dam past 24-months cumulative inflow/statistical inflows
180,000
160,000
140,000
120,000
100,000
80,000
Inflows (ML) 60,000
40,000
20,000
0 Nov-17 Feb-18 May-18 Aug-18 Nov-18 Feb-19 May-19 Aug-19
minimum 80th Percentile 50th Percentile 20th Percentile Actual inflow
Three-month weather forecast
Forecasts from the Bureau of Meteorology (BoM) indicate a warmer and drier summer ahead. The strong positive Indian Ocean Dipole (IOD) event continues, while the El Niño–Southern Oscillation (ENSO) remains neutral. The BoM indicate the positive IOD is so strong that it is likely to take several weeks to decline and could persist into mid-summer. A positive IOD typically brings below average spring rainfall to southern and central Australia, with warmer days for the southern two-thirds of the country. Positive IOD events are often associated with a more severe fire season for southeast Australia. The figure below shows that there is a 35-40% probability of the Peel Valley receiving above average rainfall during the December 2019 to February 2020 period.
10 Chaffey storage forecast
While rainfall over spring is forecast to be below average, weather patterns can change - especially over summer where northern New South Wales can see increased rainfall with the northern monsoonal season.
The figure below demonstrates the behavior of Chaffey Dam under different inflow conditions through to October 2021.
Chaffey Dam forecast storage volume - chance of exceedance (COE)
100,000
80,000
60,000
40,000
20,000 Storage capacity (ML)
0 Nov-18 Feb-19 May-19 Aug-19 Nov-19 Feb-20 May-20 Aug-20 Nov-20 Feb-21 May-21 Aug-21
Minimum 99% COE DRY 80% COE Median 50% COE WET 20% COE actual
Under wet conditions (dark blue line) with 20th percentile inflows (meaning flows that are expected to exceed in only 2 years out of 10), the dam may reach 102,000 ML (100%) and spill by the end of November 2020.
Under median conditions (light blue line) with inflows expected to exceed 5 years out of 10, the storage is likely to exceed 80% capacity by September 2021.
A dry scenario (green line), where conditions are expected to exceed this inflow 8 years out of 10, would still see the storage improve to above 50% capacity by September 2021.
The forecast under a repeat of minimum inflow (grey) conditions indicates that Chaffey Dam will reduce to a minimum of about 1% of capacity by June 2021.
While the short-term forecast is for dry conditions to continue through to summer, a change in weather patterns could see conditions improve quickly.
11 Annual operations Deliverability
The following figure shows a depletion curve for Chaffey Dam considering zero inflows to the dam, and zero downstream tributary flows.
It indicates that at 1 October 2020, there will be cease-to-flow conditions from Chaffey Dam as the dam reaches deep storage level.
While the use of the zero-inflow scenario is extremely conservative due to the very dry catchment and the significant depletion of soil moisture across the catchment, the use of this extreme scenario is justified.
Notes:
The above forecast scenario is based on the end of October 2019 assessment and considers:
• Nil access to general security or ECA from 1 July 2019. • 7,200 ML/year total demand. • Running the river till midpoint of Tamworth and Carroll until November 2019, transmission loss considered 13,000 ML/year based on recent 2018-19 observed conditions. • From December 2019 and onwards, running the river from Chaffey to Dungowan village, and then through Dungowan pipeline to Tamworth. Transmission loss considered 2,100 ML/year from December 2019 for this option. • From April 2020 and onwards, running the river from Chaffey to Dungowan village through the pipeline, and then through Dungowan pipeline to Tamworth, transmission loss considered 0 ML/year from April 2020 onwards for this option. • 2,400 ML deep storage level. While water has been allocated to towns and high security users in the valley, WaterNSW’s ability to deliver the water during the year will be dependent upon system inflows. While total water use by customers in the valley is likely to be in the order of 8,000 ML for the year, river conveyance losses are expected to be high due to dry conditions.
12 Critical human needs
Operating the system under normal operating conditions, with a continuation of the dry conditions that have been observed across the valley over the last two years, could see the system fail within the next 12 months.
Reducing the length of the river that is operated will conserve water while still allowing water to be delivered for the highest priority users under the Water Management Act 2000 (town water supply).
Stage 1 Drought emergency works – cease flows at Dungowan
Running the river from Chaffey to Dungowan village and then through the Dungowan pipeline will reduce the releases from Chaffey to meet critical needs in the Peel Valley. The losses associated with running the river to Dungowan is estimated to be 25% of the monthly maximum loss estimated under the normal operations. The reduced losses are forecast to occur from November 2019.
Critical environmental needs
The freshwater environment of the Peel Valley is comprised of a range of aquatic habitats, including in-stream pools, small flood runners, anabranches, point gravel bars and terraces. Of particular importance for the riverine ecology of the Peel are the in-channel structures such as terraces or benches on which debris or detrital material deposits accumulate during low flows.
WaterNSW, in partnership with NSW Department of Primary Industries - Fisheries and NSW Office of Environment and Heritage, will be identifying critical habitat along the Peel River and establishing a monitoring program to assess the health of these sites during the drought.
Based on the monitoring program results, water entering the Peel from downstream tributaries may be able to be used to help protect the health of critical environmental habitat.
Basic Landholder Rights and Domestic and Stock
Under the Water Management Act 2000, extraction of water for Basic Landholder Rights (BLR) does not require a licence. Although in the case of accessing groundwater under BLR, the water supply work must still be approved. BLR includes water for Domestic and Stock purposes extracted from a water source fronting a landholder’s property or from any aquifer underlying the land.
After November 2019, any access downstream of Dungowan will be dependent upon rainfall events within the valley producing run-off into the system.
Scenarios
Inflow scenarios and management outcomes:
1. Inflow event upstream of Chaffey Dam i. Any upstream event of Chaffey Dam may potentially delay the timing of Dungowan block bank. ii. Any upstream event, post installation of the temporary weir, will need to increase storage volume to ensure two years of supply to trigger the removal of the temporary weir.
2. Small tributary inflows downstream of Dungowan (< 1,000 ML) i. Any small events will be used to meet critical needs.
13 3. Medium tributary inflows (around 1,000 – 5,000 ML)
i. Medium events will be used to meet critical needs including BLR and Domestic and Stock use and potentially within the Namoi Valley (if they are identified as being in a critical state). ii. Uncontrolled flows access may be provided to Peel general security users if the flow is not required to meet critical needs in the Namoi Valley and is not required to contribute to connectivity flows.
4. Large tributary inflows (> 5,000 ML) i. Where downstream systems (Namoi or Barwon-Darling) have been identified to have critical human and/or environmental sites at risk, large flows may be protected to provide connectivity flows to these systems. ii. Uncontrolled flows access may be provided to Peel general security users if the flow is not required to meet critical needs in the Namoi Valley and is not likely to provide a connectivity flow in the Barwon-Darling.
Deliverability of ordered water
River section Licence category Type of restriction Period of Method of placing applicability water order Chaffey Dam Local water utility Delivery of account Until further Only via customer to Tamworth water will be provided notice help desk. Orders High security from Chaffey Dam until a cannot be placed temporary weir is installed via iWAS. Domestic and at Dungowan in November. Stock Confirmation of water order A water order is still General security from WaterNSW is required to be placed and (zero allocation) required. needs to be approved by WaterNSW.
Tamworth to High security From 1 July, limited Until further Only via customer Carroll Gap supplies to high security notice help desk. Domestic and and Domestic and Stock Stock licences will be provided. Confirmation However, water shortages of water order General security and/or delays in the from WaterNSW is (zero allocation) delivery of water should be required. expected. Access may become available from tributary inflows or possibly from existing river pools. A water order is still required to be placed and needs to be approved by WaterNSW.
14 Critical dates
Installation of temporary weir at Dungowan Water quality Deliverability of Domestic issues at low No general and Stock and high secuity storage levels, security limited to tributary event potential impact allocations or downstream of on Tamworth ECA delivery Dungowan supply 1 JULY 2019 1 DECEMBER 2019 30 NOVEMBER 2019
Projects
The following options can be considered as emergency response plans for drought management in Peel Valley:
1. installation of a temporary weir at Dungowan
2. pipeline from Chaffey Dam to Dungowan
3. significant industries arranging alternate water supplies.
15 16