CONTENTS

UNDERSTANDING WATER & OUR BUSINESS 01 THE 2014-2015 WATER YEAR – WHAT WATER CAME IN 16

OVERVIEW OF 03 INFLOWS 16 HOW THE SNOWY SCHEME WORKS 06 SNOWY SCHEME STORAGES 17 THE SNOWY- DEVELOPMENT 07 LAKE LEVELS 17 THE SNOWY-MURRAY DEVELOPMENT 08 COMPLYING WITH OUR LICENCE- WHAT WATER WENT OUT 20 UNDERSTANDING WATER & THE SCHEME 09 WESTERN RELEASES 21 SHARING OF INFLOWS BETWEEN CATCHMENTS 12 ENVIRONMENTAL RELEASES 25 OPERATIONS 13

Lake Eucumbene

WATER REPORT 2014 – 2015 FOREWORD

Since the Snowy Scheme’s completion in 1974, Snowy Hydro Limited has been the custodian of the water that flows through the Scheme’s complex maze of , tunnels, aqueducts and power stations.

This report outlines how we are managing that water and steps we are taking to minimise the impact of our operations on the environment.

Snowy Hydro has always operated under a strict Water Licence which governs how we can use the water that is collectively the property of the people of and . There are also strong environmental safeguards that govern our operations and our presence in the Kosciuzko National Park.

Snowy Hydro is an exemplary corporate citizen and we take our obligations to meet the conditions of our licences and any regulations applying to our business very seriously.

We are privileged to operate in some of the most picturesque areas of the and we understand that locals and visitors alike are attracted to the area because of the beautiful dams and waterways.

This report is an important channel to educate and inform our stakeholders about the water operations of the Snowy Scheme. After all, while we benefit from the water that moves through our Scheme we don’t own a drop of it; nor do we sell the water or charge people to access it.

The Snowy Scheme was constructed to collect and move water east to west and into the food bowl of . But our core purpose is to operate a complex hydro-electric scheme that generates as the market demands and where it makes commercial sense for us to do so. Importantly, helps drive revenue to pay for the maintenance and upgrade of the iconic infrastructure that is the Snowy Hydro Scheme.

We continue to effectively balance our commercial imperatives with our environmental obligations. Snowy is an important part of the Australian story and the communities we live and operate in.

I hope you find this report on our operations informative.

Paul Broad

CEO & Managing Director

Eight Mile Creek

WATER REPORT 2014 – 2015 01 02

UNDERSTANDING WATER & OUR BUSINESS

The fundamental driver for water operations of the Snowy Hydro also has to fund both the debt and Snowy Scheme is the Snowy Water Licence. operating costs of the Scheme through its participation in the highly competitive National Electricity Market The Snowy Water Licence, issued by the New South (NEM). Those electricity revenues pay for the Wales Government, regulates Snowy Hydro in terms increasing costs of maintaining and operating the of what we can do with the water in the Scheme. It has Scheme, including the costs associated with making many legally binding, enforceable obligations on the environmental flows. company. Downstream water users (irrigators and environmental Snowy Hydro is obligated under the Snowy Water entitlements holders) have never been charged for the Licence to: water regulation services provided to them each year.

1. Target water releases to the River Murray and In summary, Snowy Hydro has flexibility from day catchments, the annual to day in releasing water from the Scheme as an volumes of which are determined according to outcome of generating electricity. Each year, we have highly prescriptive formulae set out in the Snowy to reach certain targets for releases. The short-term Water Licence; flexibility allows us to run our electricity business, 2. Targeting water releases from Jindabyne into while at the same time giving long-term security to the the for environmental purposes (Snowy downstream users around annual water releases. River Increased Flows); and Whilst the Snowy Water Licence recognises the 3. Facilitating additional natural flows to nominated difficulties inherent in achieving precise release for environmental purposes (Snowy Montane volumes at each release point, any shortfall or excess Rivers Increased Flows). is accounted and generally dealt with by an ‘unders’ and ‘overs’ approach whereby the shortfall or excess To generate electricity Snowy Hydro must release is added or subtracted to the following years target. water from the Snowy Scheme, and to release water I.e. there is no way that Snowy Hydro can consistently from the Snowy Scheme, Snowy Hydro must generate ‘under-deliver’ water to any aspect of the release electricity. In this way, water releases and electricity program. generation are inseparably linked. For more information and a full copy of the Snowy Snowy Hydro must operate the Scheme to first meet Water Licence we encourage people to visit its water release obligations and then to maximise www.water.nsw.gov.au electricity market opportunities within the constraints imposed by the Snowy Water Licence.

Talbingo

WATER REPORT 2014 – 2015 UNDERSTANDING 03 04

OVERVIEW OF SNOWY HYDRO

Snowy Hydro Limited has a long and proud history as an Australian company. The construction of the Scheme is a well documented part of our nation’s history and we are a great example of Aussie innovation and ingenuity.

From those beginnings, we have become a dynamic Snowy Hydro operates under a stringent water licence and growing end to end provider with the that allows us to capture, store and divert water complete service offering, still backed by the mighty in order to generate electricity. That water is then Snowy. We’ve evolved from an electricity generator released into the River Murray and Murrumbidgee managing electricity price risk in the NEM, to an River systems to be used by irrigators and integrated energy business - generating energy, downstream water suppliers. providing price risk management products for wholesale customers and delivering energy to homes We do not generate electricity constantly but rather and businesses. we capitalise on periods when electricity demand is high - such as when people are using air conditioners We combine the power of the mighty Snowy Scheme or heaters during summer and winter. with gas and diesel fired peaking generators to deliver a flexible and reliable mix of energy to our customers Key to our success is our ability to utilise the Snowy every day. We have 16 power stations, generate 4,500 Scheme’s large, reliable and fast start capability to Gigawatt hours (GWh) on average per annum and our advantage whether it’s through spot generation, have more than 5,500 Megawatts (MW) of generating risk management for our wholesale customers, capacity across New South Wales, Victoria and South futures contracts or households and commercial and Australia. industrial customers.

We’ve become the fourth largest energy retailer in But over the years we’ve diversified the business and the NEM by investing more than a billion dollars rebuilt water storages post-drought to manage our risk in growing our customer base, modernising our and help make us resilient to changes in the market generating infrastructure, building and acquiring more and shifts in energy demand and variable climatic generating capacity where we need it and developing conditions. our people.

Every day we provide fast, clean electricity and gas to our one million account holders who are households and businesses - big and small - across the country. Our retail companies Red Energy and pride themselves on customer service with energy backed by one of the great civil engineering wonders of the world - the Snowy Scheme.

Tumut 3

WATER REPORT 2014 – 2015 UNDERSTANDING 05 06

Tumut

Blowering Power Station

Blowering Reservoir Jounama Small Hydro Power Station Talbingo Tumut 3 Power Station Tantangara Talbingo Reservoir Reservoir HOW THE SNOWY SCHEME WORKS The Snowy Scheme was designed to collect and store water, including water that would otherwise flow east Tumut 2 UG Kiandra down the Snowy River to the coast, diverting it through trans-mountain tunnels and power stations and then Power Station NORTHERN releasing it west of the Snowy Mountains into the catchments of the River Murray and the Murrumbidgee River, Cabramurra Tumut 1 UG where it can be used for town water supply, irrigation and environmental uses. Power Station SNOWY-TUMUT Lake The Snowy Scheme includes: Eucumbene ŸŸ Nine power stations – Murray 1, Murray 2, Blowering, Guthega, Tumut 1 (located 366m below ground level), Tumut 2 (located 244m below ground level), Tumut 3, Jounama Small Hydro Power Station and Jindabyne Mini Hydro Power Station;

Khancoban ŸŸ One pumping station at Jindabyne and a pump storage facility at Tumut 3 Power Station; Pondage Murray 1 Murray 2 Power Station ŸŸ 16 major dams with a total storage capacity of 7,000 gigalitres (GL) or almost 12 times the volume Power Station of Harbour; Jindabyne Guthega Pumping Station Power Station Berridale ŸŸ 145km of inter-connected tunnels and pipelines and 80km of aqueducts; and Lake Mt Kosciuszko JindabyneJindabyne ŸŸ 33 hydro-electric turbines with a generating capacity of 4,100MW. Jindabyne Mini Hydro Power Station The Snowy Scheme comprises two major developments: the Northern Snowy-Tumut Development and the Thredbo Power or Pumping Station Southern Snowy-Murray Development. The water in Lake Eucumbene, our large long-term storage lake, Dalgety Underground Power Station is split between the two developments based on where the water was collected from. Tunnel Snowy Hydro Limited Water Catchment Boundary River Water Storage SOUTHERN SNOWY-MURRAY

WATER REPORT 2014 – 2015 UNDERSTANDING Blowering Reservoir Tooma Reservoir Ogilvies Intake Deep Creek Intake 1500 Jounama Talbingo Outstation Pondage Reservoir Intake Intake

1200 Blowering Tumut 3 Power Station Power Station 900 Murrumbidgee River Jounama Small Hydro Power Station 600 Tumut 2 Happy Jacks Tantangara Pondage Pondage Lake Eucumbene Reservoir Tumut River 300 Tumut Pond Reservoir Tumut River To Murrumbidgee Power or Pumping Station 0 Irrigation Area Tumut 2 Tumut 1 Power Station Power Station Underground Power Station

Tunnels and Shafts

07 08

2100 Blowering Reservoir Tooma Reservoir Ogilvies Intake Khancoban Murray 1 Geehi Reservoir Guthega Pondage Island Bend Jindabyne Lake Eucumbene Pondage Power Station Pondage Pumping Station Deep Creek Intake 1500 1800 Jounama Talbingo Outstation Burns Creek Murray 2 Bourkes Gorge Burrungubugge Lake Jindabyne Pondage Reservoir Intake Intake Power Station Intake Intake

1200 1500 Blowering Tumut 3 Jindabyne Mini Hydro Power Station Power Station Power Station Snowy River 900 Tumut River Murrumbidgee River 1200 Jounama Small Hydro Power Station 600 Tumut 2 Happy Jacks Tantangara 900 Snowy River Pondage Pondage Lake Eucumbene Reservoir Tumut River 300 Tumut Pond 600 To Tasman Sea Reservoir Tumut River To Murrumbidgee Power or Pumping Station Geehi River 0 Irrigation Area Tumut 2 Tumut 1 300 Power Station Power Station Underground Power Station Swampy Plains River Power or Pumping Station 0 To Tunnels and Shafts Murray 2 Pondage Tunnels and Shafts

THE SNOWY-TUMUT DEVELOPMENT THE SNOWY-MURRAY DEVELOPMENT

The Snowy-Tumut Development consists of five Blowering Power Station is located on The Snowy-Murray Development consists of four Additionally, the Jindabyne Small-hydro Power Station power stations and 16 generating units. It collects the and is leased from NSW State Water Corporation. power stations with 17 generating units and one allows Snowy Hydro to recover a small amount of headwaters of the upper Murrumbidgee, Tooma and Water releases from Blowering Dam are controlled pumping station. Water in the upper Snowy River electricity from some of the environmental releases Eucumbene Rivers. Those waters are diverted through by State Water to provide for downstream town is diverted at through Guthega Power made from into the Snowy River. trans-mountain tunnels to Tumut Pond Dam where they water supply, extractive and environmental use Station and back into . Inflows into 2100 From Geehi Reservoir, with additional water from join the watersKhancoba of nthe TumutMurray 1 River and flowGeehi R ethroughservoir Gurequirements.thega Pondage Island Bend Jindabyne Lake Eucumbene the relatively small Guthega Pondage are seasonal Pumping Station Tumut 1 andPon Tumutdage 2 undergroundPower Station power stations, Pondage and spills of the reservoir are common, particularly the Geehi River, the water from Island Bend and 1800 Blowering Power Station is therefore a ‘run of river’ Eucumbene passes through Murray 1 and Murray discharging intoM Talbingourray 2 Reservoir.Bourkes Go Waterrge stored in Burrungubugge Lake Jindabyne during the spring snowmelt period. Power Station Intake Intake Talbingo Reservoir then passes through the Tumut 3 plant that operates as State Water releases water 2 power stations. regulates water 1500 Power Station and into Jounama Pondage. from Blowering Dam into Jindabynethe Tumut Mini Hydro River, Power Stationwhich During times of high inflows, water flowing into Island released from Murray 2 Power Station down the joins the Murrumbidgee River near . On the Bend Pondage is diverted to Lake Eucumbene for Swampy Plains River which is a of the upper 1200 Snowy River Three of the six generating units at Tumut 3 PowerGeehi River Murrumbidgee River at Gundagai, the Snowy Scheme storage and subsequently transferred to the River River Murray. On the River Murray at , the

Station900 also have large pumps fitted that can be used contributesSnowy River around 25% of inflows during average Murray catchment at a later time. At times of low Snowy Scheme contributes inflows of only around 8% to pump water from Jounama Pondage back up into inflow years but can provide up Eucumbeneto 60% of River the total inflows, water from Island Bend Pondage is diverted during average inflow years but can contribute up to

Talbingo600 Reservoir, thereby ‘recycling’ water. Water inflows to this location duringTo Tasman drought Sea years. to Geehi Reservoir through a trans-mountain tunnel, 33% of inflows during drought years. cannot be pumped any further uphill than Talbingo together with water transferred back from Lake Geehi River Reservoir.300 Eucumbene. Swampy Plains River Power or Pumping Station 0 To Murray Irrigation Area Water is released fromMurray Jounama 2 Pondage Dam into Blowering Guthega Power Station Tunnels and Shafts The Jindabyne Pumping Station pumps water from Reservoir either through the Jounama Small Hydro Lake Jindabyne, normally using off-peak power Power Station or through the radial release gates at (typically at night and on weekends) into Geehi . Reservoir on the western side of the Great Dividing Range. Water from Lake Jindabyne cannot be pumped back to Lake Eucumbene or to Island Bend Dam.

WATER REPORT 2014 – 2015 UNDERSTANDING 09 10

Guthega Dam

UNDERSTANDING WATER & THE SCHEME

Definitions: 6000

Water Year- The Snowy Hydro water year commences on 1 May and concludes 5000 on 30 April each calendar year.

1 gigalitre (GL)- Equal to 1,000 megalitres (ML). 4000 1 megalitre (ML)- Equal to 1 million litres (L).

3000 Variability:

2000

The Snowy Scheme was designed to cope with large variability in inflows. In the last 109 years of data, inflows pa) Snowy Scheme Inflows (GL have ranged from 683GL seen in 2006/07 during the worst drought on record, to 5761GL almost a century ago in 1917. The long term average is just below 2800GL. 1000 The total volume of Snowy Scheme storages is massive and it will take a number of consecutive years of above average inflows to return our total storage volumes, particularly Lake Eucumbene, to above average levels. Average Inflows = 2781 GL pa 0 We can expect to receive around 50% of our inflows from snowmelt and rain during spring, so a bad snow 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 season can have a significant impact on the total inflows for the year. Water Year

WATER REPORT 2014 – 2015 UNDERSTANDING 11 12

Water ownership: SHARING OF INFLOWS BETWEEN The Snowy Water Licence states that Snowy Hydro has the right to collect, divert, store and release water. That, in no way, represents any form of ownership of the water. The parties who have an entitlement to releases CATCHMENTS from the Snowy Scheme own all of the water in the Scheme. This includes the states of New South Wales and Victoria, irrigators from those states, downstream town water supplies and the environment. One of the key functions of the Snowy Scheme is to divert flows from rivers of the Eastern side of the Dividing The water you see in Lake Jindabyne, Tantangara Reservoir, Lake Eucumbene and all of the other Snowy Hydro Range to the West. The Snowy Water Licence prescribes how each of the three catchments are allocated to either storages has already been secured and allocated to the above mentioned parties by the Government. of the two developments of the Scheme.

Of all the inflows into the Snowy Scheme, each year some water will be lost to evaporation, seepage and Snowy Hydro has some flexibility around the short-term timing of releases to meet energy generation needs occasionally water will be spilt when the inflows are too great for the Scheme to control. This water is subtracted throughout the year. However, by the end of each water year (which ends in April), Snowy Hydro has to have from the total inflow to determine the usable catchment yield. The yield is distributed as per the below diagram released a predetermined volume of water out of the Scheme. This is one of the legally binding obligations set and released through the dams and power stations on its way to the Murray, Murrumbidgee and Snowy Rivers. out in the Snowy Water Licence. The diagram represents the long term average volume of water that is collected by, diverted between and released from, each of the three main river catchments in the Scheme.

These values are based on analysis of long term data and have taken into account the increase in environmental Water content of snow: flows targeted for release down the Snowy River and the consequent reduction in diversion and releases to the River Murray and Murrumbidgee River. Tantangara Reservoir

In the Snowy Mountains, the density (or water

content) of freshly fallen snow is about 20-25%: Snowy yield 1040GL 1mm of rain equals about 5mm (0.5cm) of snow. Murrumbidgee yield ACT Fresh snow has a relatively low water content, Murray yield and as the winter season progresses, the average Snowy diverted to Murrumbidgee density of snow on the ground tends to increase as it Murray diverted to Murrumbidgee compresses. Throughout the season, the density of 660GL snowpack in the Snowy Mountains generally ranges Tantangara Reservoir from as little as 25% up to 50%. So, if there is a

two metre snowpack, that would be the equivalent TUMBARUMBA of between 50 and 100cm of water sitting on the mountain at that point. 100GL

How much of this water makes it into the when the snow melts is another matter. Snowmelt is strongly impacted by the weather conditions ADAMINABY experienced during late winter and spring, and small VICTORIA 280GL Lake NEW SOUTH changes in the weather can lead to vastly different Eucumbene WALES outcomes for inflows. For example heavy rain falling on a dense snowpack melts the snow quickly and 1070GL maximises runoff, and hot northerly winds help to KHANCOBAN melt the snow but when the air is dry, much of the 1060GL Great COOMA Dividing water can evaporate rather than run off into the Range streams or rivers. 610GL 740GL Lake BERRIDALE Jindabyne

220GL

NIMMITABELNIMMITABEL

G r e a t D i v i d i n g WATER REPORT 2014 – 2015 RUNDERSTANDING a n g e 13 14

Snowy Hydro does not determine releases from the Scheme or to irrigators:

Snowy Scheme releases and the other River Murray and Murrumbidgee River catchment inflows are re-regulated by Hume Dam on the River Murray and Blowering Dam on the Tumut River – neither of which are owned or controlled by Snowy Hydro.

Water releases for extractive and environmental uses along the Upper River Murray are managed by the Murray- Darling Basin Authority, principally through releases from Dartmouth and Hume Dams (the Snowy Scheme does not make releases into nor has any control over the operation of ).

Water releases for extractive and environmental uses along the Murrumbidgee River are managed by the NSW State Water Corporation, principally through releases from Blowering and Burrinjuck Dams (again, the Snowy Scheme does not have any control over the operation of ).

SNOWY SCHEME SCHEME GOVTGOVT OWNED OWNED && OPERATED OPERATED

ENVIRONMENT TOWN WATER SUPPLY MURRUMBIDGEE IRRIGATION LTD

BURRINJUCK DAM (NSW STATE WATER)

Eucumbene River MURRUMBIDGEE RIVER

SNOWY TUMUT DEVELOPMENT

BLOWERING DAM ENVIRONMENT TOWN WATER SUPPLY MURRUMBIDGEE IRRIGATION LTD FLOOD OPERATIONS (NSW STATE WATER)

Flooding occurs when the channel capacity is as Khancoban, Geehi or Talbingo. These are small exceeded and flows overtop onto the floodplain. storages and once they are full, the water must flow ENVIRONMENT TOWN WATER SUPPLY MURRAY IRRIGATION LIMITED (NSW) When the channel capacity of the rivers downstream downhill. of the Snowy Scheme is exceeded, our releases are To pass the water safely and effectively through the limited to what the flows would have been had the HUME DAM Scheme, Snowy Hydro aims to utilise our series of (RIVER MURRAY WATER) Scheme not existed. This is known as the calculated NSW power stations where possible, rather than operating ‘Pre-SMA’ flow. RIVER MURRAY other spillways at a dam. This means we must VIC This means that during a flood we do not release generate and will often have to bid that power into the SNOWY MURRAY any more water than what would have naturally NEM at very low prices (even possibly at $0) to ensure DEVELOPMENT flowed down the river. As such, we do not in any way that our plant is dispatched to pass flood flows.

exacerbate flooding downstream of the Scheme. DARMOUTH DAM ENVIRONMENT TOWN WATER SUPPLY GOULBURN MURRAY WATER (VIC) During flood operations, we liaise closely with the (RIVER MURRAY WATER) The Scheme can provide limited storage capacity for BoM, local SES and councils to ensure that the most high inflows, which in turn can provide some short up to date information is available for landholders and term assistance. However, water cannot be diverted flood response activities. back to Eucumbene from lower catchments such

WATER REPORT 2014 – 2015 UNDERSTANDING 15 16

THE 2014-2015 WATER YEAR – WHAT WATER CAME IN INFLOWS

Snowy Scheme inflows for 2014–15 were 2,209GL which is about 79% of the long term average of 2,781GL.

We would need multiple years of average or above average inflows to see major sustained improvements in lake levels. In 2014-15 we received below average inflows, therefore further increasing the time it will take for storages to return to long-term average levels.

SNOWYSNOWY SCHEME SCHEME INFLOWS INFLOWS FOR FOR MAY MAY 2014 2014 TO TO APRAPRIL 2015 2015

6000 Critical Inflow Months

5000

4000

3000

Cumulative Inflows (GL) 2000

1000

0 May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Month

Very Wet Average Very Dry 2014-2015 Actual

Lake Eucumbene

WATER REPORT 2014 – 2015 THE 2014 – 2015 WATER YEAR 17 18

SNOWYSNOWY SCHEME ACTIVE ACTIVE STORAGE STORAGE FOR 2014-2015 FOR 2014-2015WATER YEAR WATER YEAR

6000

5000

4000

3000 SNOWY SCHEME STORAGES Storage (GL) 2000

Total Active Storage 1000 Snowy Scheme storage levels are referred to in different measurements, they being ‘Active Storage’ and Actual Storage

‘Gross Storage’. Long Term Average Storage

0 Active storage is the water that generally can be accessed by either pumping or through release via dams Apr 14 May 14 Jun 14 Jul 14 Aug 14 Sep 14 Oct 14 Nov 14 Dec 14 Jan 15 Feb 15 Mar 15 Apr 15 or through power stations. Gross storage is the total amount of water behind the dam wall including the End Month water than cannot ordinarily be accessed due to the design of the Scheme infrastructure. LAKE JINDABYNE GROSS STORAGE FOR 2014-2015 WATER YEAR For the purposes of our business operations, active storage is used, whereas recreational users are LAKE JINDABYNE GROSS STORAGE FOR 2014-2015 WATER YEAR generally more interested in and familiar with gross storage. For example, Lake Jindabyne could 100

experience a 0% active storage level but the lake itself would be then at approximately 44% gross storage. 90 This remaining water cannot be accessed via the pumping station due to the physical design limitations of 80 the Scheme.

70 At the end of the 2013–14 water year, Snowy Scheme active storage was 2,168GL. This is equivalent to 40.9% of the total active storage capacity. 60

% Full 50 During the 2014–15 water year, active storage increased by 395GL to 2,563GL at the end of the year, which is 48.3% of the total active storage capacity. 40

30

20 Actual Storage 10 Long Term Average Storage LAKE LEVELS 0 Apr 14 May 14 Jun 14 Jul 14 Aug 14 Sep 14 Oct 14 Nov 14 Dec 14 Jan 15 Feb 15 Mar 15 Apr 15

End Month The Snowy Scheme’s main storage, Lake Eucumbene, ended the 2014-15 year higher than the previous year but still below the long-term average storage level. LAKELAKE EUCUMBENEEUCUMBENE GROSS GROSS STORAGE STORAGE FOR 2014-2015 FOR 2014-2015WATER YEAR WATER YEAR

The level of Lake Jindabyne at the end of the 2014-15 water year was lower than that of the previous year, 100

and the storage level remains well above the long term average storage level. Snowy Hydro now maintain 90 a higher lake level in order to ensure security of supply for the flushing flows out of Jindabyne Dam into the Snowy River. 80

70 Snowy Hydro reports gross storage levels to local tourism operators and the local community on the SnowyLIVE App and on our website. Lake Levels for our three main storages of Jindabyne, Eucumbene 60

and Tantangara are provided weekly and are available at www.snowyhydro.com.au. The SnowyLIVE App % Full 50 can be downloaded from the Apple App Store or Google Play. The website also includes a lake level 40 comparison calculator where it can be seen that lake levels have improved since the height of the drought in 2006–07 in line with improvements in annual inflows. 30

20 Actual Storage 10 Long Term Average Storage

0 Apr 14 May 14 Jun 14 Jul 14 Aug 14 Sep 14 Oct 14 Nov 14 Dec 14 Jan 15 Feb 15 Mar 15 Apr 15

End Month

WATER REPORT 2014 – 2015 THE 2014 – 2015 WATER YEAR 19 20

COMPLYING WITH OUR LICENCE WHAT WATER WENT OUT

Snowy Hydro complied with all of the requirements imposed upon the company under the Snowy Water Licence during the 2014–15 water year including each water release target relating to:

ŸŸ The Required Annual Release to the River Murray catchment

ŸŸ The Required Annual Release to the Murrumbidgee River catchment

ŸŸ Environmental releases into the Snowy River from Jindabyne Dam

ŸŸ Environmental releases into the Murrumbidgee River from

ŸŸ Environmental releases into the from Goodradigbee Aqueduct

ŸŸ Environmental releases into the Geehi River from Middle Creek Aqueduct

ŸŸ Environmental releases into the Snowy River from Bar Ridge and Diggers Creek Aqueducts

Khancoban Dam

WATER REPORT 2014 – 2015 COMPLIANCE INFLOWS AND RELEASES TO THE RIVER MURRAY CATCHMENT DURING 2014-2015

21 22

WESTERN RIVER RELEASES INFLOWS AND RELEASES TO THE RIVER MURRAY CATCHMENT DURING 2014-2015 1200 RIVER MURRAY CATCHMENT

1000 Snowy Hydro complied with its obligation to target the Required Annual Release (RAR) from the Snowy-Murray Development to the River Murray catchment during the 2014–15 water year. 800 The total accounted release volume was 762GL. This was made up of:

ŸŸ 760GL being the 2014–15 Required Annual Release calculated under the Snowy Water Licence; plus 600 Gigalitres ŸŸ 2GL of pre-release of the 2015–16 Required Annual Release; plus

Ÿ Ÿ 0GL of Discretionary Above Target Water Releases (water not required for RAR releases that Snowy Hydro 400 is able to release at its discretion).

This total accounted release volume includes 14GL of Montane environmental flow releases provided to the Geehi and Swampy Plains River which did not flow through Scheme power stations. 200

0 Long Term Average Inflows 2014-2015 Actual Inflows 2014-2015 Actual Release

Khancoban Pondage

WATER REPORT 2014 – 2015 COMPLIANCE INFLOWS AND RELEASES TO THE MURRUMBIDGEE CATCHMENT DURING 2014-2015

23 24

INFLOWS AND RELEASES TO THE MURRUMBIDGEE CATCHMENT DURING 2014-2015 MURRUMBIDGEE RIVER CATCHMENT 1400

Snowy Hydro complied with its obligation to target the Required Annual Release from the Snowy-Tumut 1200 Development to the Murrumbidgee River catchment during the 2014–15 water year.

The total accounted release volume was 623GL. This was made up of: 1000 ŸŸ 623GL being the 2014–15 Required Annual Release calculated under the Snowy Water Licence; plus

ŸŸ 0GL of pre-release of the 2015–16 Required Annual Release; plus 800

ŸŸ 0GL of Discretionary Above Target Water release (water not required for RAR releases that Snowy Hydro

is able to release at its discretion). Gigalitres 600

This total release volume includes 27GL of montane environmental flow releases provided to the Murrumbidgee and Goodradigbee Rivers which did not flow through Scheme power stations. 400

200

0 Long Term Average Inflows 2014-2015 Actual Inflows 2014-2015 Actual Release (Upper Tumut) (Upper Tumut)

Jounama Dam and Pondage

WATER REPORT 2014 – 2015 COMPLIANCE SRIF AND JINDABYNE BPF RELEASES INCL MOWAMBA RIPARIAN RELEASES

25 26

SRIF AND JINDABYNE BPF RELEASES INCL MOWAMBA RIPARIAN RELEASES

Number of months when SRIF release were outside monthly limits = 0

50 200

40 160

30 120

Monthly Releases (GL) 20 80 Progressive Releases (GL)

10 40

0 0 1-May-14 1-Jun-14 1-Jul-14 1-Aug-14 1-Sep-14 1-Oct-14 1-Nov-14 1-Dec-14 1-Jan-15 1-Feb-15 1-Mar-15 30-Apr-15 SNOWY MONTANE RIVERS INCREASED FLOWS FROM TANTANGARA DAM AND DAILY LIMITS Actual SRIF Releases Target Progressive SRIF SRIF Monthly Target + 20% SRIF Annual Target + 10%

Actual BPF Releases Actual Progressive SRIF SRIF Monthly Target - 20% SRIF Annual Target - 10% Snowy River Flushing Flows

SRIF AND JINDABYNE BPF RELEASES AND DAILY LIMITS ENVIRONMENTAL RELEASES Number of days when Jindabyne releases were outside daily limits= 0 9000

SNOWY RIVER INCREASED FLOWS 8000

7000 Snowy Hydro complied with its obligation to target All monthly releases were within the +/–20% monthly releases from Jindabyne Dam for environmental tolerance around the target volumes and daily 6000 purposes during the 2014–15 water year. releases were within the +/–20% daily tolerance allowed under the Snowy Water Licence. 5000 The volume of Snowy River Increased Flows (SRIF) released from Jindabyne Dam during the 2014–15 As allocations for the 2014–15 water year once again 4000 water year was 147.6GL, which was 0.8GL above exceeded 100GL, a flushing flow was delivered to the the target volume of 146.8GL. That excess is well Snowy River through the spillway and cone valves at 3000 within the +/–10% annual tolerance around the target Jindabyne Dam in October 2014. Daily Releases (ML/day) volumes allowed under the Snowy Water Licence. 2000 The 2015–16 target has been adjusted down to The comparison of the annual, monthly and daily account for this release surplus. release targets for the Snowy River Increased Flow 1000 releases against the actual releases is shown in the In addition to the environmental releases, 8.5GL Base following charts. 0 Passing Flow (BPF) was also released from Jindabyne

1-May-14 10-Jul-1424-Jul-147-Aug-14 4-Sep-14 2-Oct-14 8-Jan-15 5-Mar-15 2-Apr-15 Dam and 0.5GL riparian flow was released from the 15-May-1429-May-14 12-Jun-1426-Jun-14 21-Aug-14 18-Sep-14 16-Oct-1430-Oct-1413-Nov-1427-Nov-1411-Dec-1425-Dec-14 22-Jan-1505-Feb-1519-Feb-15 19-Mar-15 16-Apr-1530-Apr-15 Mowamba Weir.

SRIF Jindabyne BPF SRIF Low Limit SRIF High Limit

WATER REPORT 2014 – 2015 COMPLIANCE 27 28

Lake Jindabyne

JINDABYNE DAM INTAKE WATER TEMERATURES AND LEVEL

THE TEMPERATURE OF RELEASES FROM LAKE JINDABYNE JINDABYNE910 DAM INTAKE WATER TEMPERATURES AND LEVEL May-14 Temp 908 Jun-14 Temp The Snowy Water Licence requires the outlet works at Jindabyne Dam to be capable of releasing water from Jul-14 Temp above any thermocline in the reservoir. The thermocline is a thin but distinct layer in a large body of water 906 Aug-14 Temp in which water temperature changes more rapidly with depth than it does in the layers above or below. Sep-14 Temp Oct-14 Temp Typically, as the summer progresses, the surface waters warm and the deeper waters remain cold. 904 Nov-14 Temp This causes a lack of mixing between the upper and lower layers, which can result in the lower layer having Dec-14 Temp reduced oxygen levels. For these reasons the deeper waters within reservoirs are generally viewed as having 902 Jan-15 Temp undesirable water quality characteristics for releases, hence the requirement for the outlet works to be able Feb-15 Temp to draw from above the thermocline. 900 Mar-15 Temp Apr-15 Temp The intake works at Jindabyne are located at the end of a channel excavated into the bank of Lake Jindabyne. 898 May-14 Dam Level Dam Level In addition to the variable level shutters in the intake tower, the level of the base of the channel means that Jun-14 Dam Level the deeper waters of the reservoir are inaccessible. This means that the thermocline is only likely to be above Jul-14 Dam Level 896 the levels of the intake channel when the lake is at high levels. Aug-14 Dam Level Sep-14 Dam Level Snowy Hydro undertakes temperature monitoring at the intake tower to detect the presence of a thermocline 894 Oct-14 Dam Level and adjusts shutter height as necessary. As can be seen in the chart opposite, all releases were made from Nov-14 Dam Level above the thermocline. 892 Dec-14 Dam Level Jan-15 Dam Level Feb-15 Dam Level 890 Mar-15 Dam Level Apr-15 Dam Level 888 Shutter Position 0 10 15 20 25

Temperature (Deg C)

WATER REPORT 2014 – 2015 COMPLIANCE SMRIF AND RIPARIAN RELEASES FROM TANTANGARA DAM

29 30 8 40

7 35 SNOWY MONTANE RIVERS INCREASED FLOWS SMRIF AND RIPARIAN RELEASES FROM TANTANGARA DAM 6Number of months when Tantangara Dam releases were outside monthly limits = 0 30

Snowy Hydro complied with its obligation to target from Bar Ridge and Diggers Creek Aqueducts, 5 25 Snowy Montane Rivers releases for Environmental all to be targeted over the water year. purposes during the 2014–15 water year. 4 20 The Snowy Montane Rivers include all rivers within The total actual montane release volume was 58.3GL. the Snowy Water Catchment Area including the Upper This was made up of 18.7GL from Tantangara Dam, Murrumbidgee River immediately below Tantangara 8.4GL from Goodradigbee Aqueduct, 14.0GL from 3 15 Dam but excluding the Snowy River, the Mowamba Middle Creek Aqueduct and 17.2GL from Bar Ridge River and Cobbon Creek. and Diggers Creek Aqueducts, released over the 2 10 water year. Releases (GL) During the 2014–15 water year, Snowy Hydro was 1 5 Progressive Releases (GL) directed to make Snowy Montane Rivers Increased The comparison of the annual, monthly and daily Flows (SMRIF) from the following locations: release targets for the Snowy Montane Rivers Increased Flows against the actual from Tantangara 0 0 1-May-14 1-Jun-14 1-Jul-14 1-Aug-14 1-Sep-14 1-Oct-14 1-Nov-14 1-Dec-14 1-Jan-15 1-Feb-15 1-Mar-15 30-Apr-15 ŸŸ Tantangara Dam to the Murrumbidgee River, Dam is set out in the graphs opposite. All daily, monthly and annual release targets were within the Ÿ Ÿ Goodradigbee Aqueduct to the Goodradigbee compliance limits. Actual SMRIF Releases Target Progressive SMRIF SMRIF Monthly Target + 20% SMRIF Annual Target + 10% River (a tributary of the Murrumbidgee River), Monthly releases from Goodradigbee, Middle Creek, Actual Riparian Releases Actual Progressive SMRIF SMRIF Monthly Target - 20% SMRIF Annual Target - 10% Ÿ SNOWY MONTANE RIVERS INCREASED FLOWS FROM TANTANGARA DAM AND DAILY LIMITS Ÿ Middle Creek Aqueduct to Middle Creek (a tributary Bar Ridge and Diggers Creek are also provided on of the Geehi River); and pages 31 and 32. As these releases are made from ŸŸ Bar Ridge and Diggers Creek Aqueducts to Tolbar small catchments and the inflows (and therefore Creek and Diggers Creek respectively ( releases) cannot be predicted or controlled, there of the Snowy River). are no annual compliance targets for these releases. The above/below target delivery of water in these SNOWY MONTANE RIVERS INCREASED FLOWS FROM TANTANGARA DAM AND DAILY LIMITS The target volume for Snowy Montane Rivers catchments in 2014-15 reflects the inflows received Number of days when montane releases were outside daily limits= 0 Increased Flows totalled 66.7GL, with 18.3GL from in these locations. In years when inflows are above Tantangara Dam, 12.0GL from Goodradigbee average, above average volumes of water will be 450 Aqueduct, 17.5GL from Middle Creek, and 18.9GL delivered to these catchments and vice versa.

400

350

Eucumbene River 300

250

200

150 Daily Releases (ML/day) 100

50

0

1-May-14 10-Jul-1424-Jul-147-Aug-14 4-Sep-14 2-Oct-14 8-Jan-15 5-Mar-15 2-Apr-15 15-May-1429-May-14 12-Jun-1426-Jun-14 21-Aug-14 18-Sep-14 16-Oct-1430-Oct-1413-Nov-1427-Nov-1411-Dec-1425-Dec-14 22-Jan-1505-Feb-1519-Feb-15 19-Mar-15 16-Apr-1530-Apr-15

Actual SMRIF Releases SMRIF Low Limit SMRIF High Limit

WATER REPORT 2014 – 2015 COMPLIANCE 31 32

Jounama Pondage

SMRIF FROM GOODRADIGBEE WEIR SMRIF FROM BAR RIDGE AQUEDUCT SMRIF FROM DIGGERS CREEK AQUEDUCT

SMRIF FROM MIDDLE CREEK AQUEDUCT SMRIF FROM GOODRADIGBEE WEIR SMRIF FROM BAR RIDGE AQUEDUCT SMRIF FROM DIGGERS CREEK AQUEDUCT

11 22 2.0 15 2.4 10 2.6 10

14 2.2 2.4 10 20 1.8 9 9 13 2.0 2.2 9 18 1.6 12 8 8 2.0 1.8 8 16 11 1.4 7 1.8 7 10 1.6 7 14 1.6 6 1.2 9 1.4 6 6 12 8 1.4 1.0 1.2 5 5 5 10 7 1.2

1.0 Releases (GL) Releases (GL) Releases (GL) Releases (GL) 4 0.8 6 4 1.0 4 8 5 0.8 0.6 3 0.8 3 Progressive Releases (GL) Progressive Releases (GL) Progressive Releases (GL) 3 6 Progressive Releases (GL) 4 0.6 0.6 0.4 3 2 2 2 4 0.4 0.4 2 1 2 0.2 1 1 1 0.2 0.2

0 0 0 0.0 0 0.0 0

1-Jun-141-Jul-14 1-Oct-14 1-Jan-151-Feb-151-Mar-15 1-Jun-141-Jul-14 1-Oct-14 1-Jan-15 1-Jun-141-Jul-14 1-Sep-141-Oct-141-Nov-14 1-Jan-151-Feb-151-Mar-15 1-Jun-141-Jul-14 1-Oct-14 1-Jan-15 1-May-14 1-Aug-141-Sep-14 1-Nov-141-Dec-14 30-Apr-15 1-May-14 1-Aug-141-Sep-14 1-Nov-141-Dec-14 1-Feb-151-Mar-1530-Apr-15 1-May-14 1-Aug-14 1-Dec-14 30-Apr-15 1-May-14 1-Aug-141-Sep-14 1-Nov-141-Dec-14 1-Feb-151-Mar-1530-Apr-15

Actual Release (GL) Actual Progressive (GL) Actual Release (GL) Actual Progressive (GL) Actual Release (GL) Actual Progressive (GL) Actual Release (GL) Actual Progressive (GL)

Water Year Target (GL) Water Year Target (GL) Water Year Target (GL) Water Year Target (GL)

Note: There are no monthly or annual compliance targets for Middle Creek. Note: There are no monthly or annual compliance targets for Goodradigbee Weir. Note: There are no monthly or annual compliance targets for Bar Ridge. Note: There are no monthly or annual compliance targets for Diggers Creek.

WATER REPORT 2014 – 2015 COMPLIANCE 33 34

THE TEMPERATURE OF RELEASES FROM TANTANGARA RESERVOIR

The Snowy Water Licence requires the outlet works at Tantangara Dam to be capable of releasing water from above any thermocline in the reservoir. The thermocline is a thin but distinct layer in a large body of water in which temperature changes more rapidly with depth than it does in the layers above or below. Typically, as the summer progresses, the surface waters warm and the deeper waters remain cold. This causes a lack of mixing between the upper and lower layers, which often results in the lower layer having reduced oxygen levels. For these reasons the deeper waters within reservoirs are generally viewed as having undesirable water quality characteristics for releases, hence the requirement for the outlet works to be able to draw from above the thermocline.

The new intake works at Tantangara Dam are located on the upstream face of the dam wall. They comprise a series of ‘telescoping’ shutters to create a variable level off-take.

Snowy Hydro undertakes temperature monitoring at the intake tower to detect the presence of a thermocline and adjusts the shutter height as necessary. As can be seen in the chart below, a persistent thermocline was not present during the 2014-15 water year.

TANTANGARA DAM INTAKE WATER TEMERATURES AND LEVEL TANTANGARA DAM INTAKE WATER TEMPERATURES AND LEVEL

1224 May-14 Temp Jun-14 Temp Jul-14 Temp Aug-14 Temp Sep-14 Temp Oct-14 Temp Nov-14 Temp 1219 Dec-14 Temp Jan-15 Temp Feb-15 Temp Mar-15 Temp Apr-15 Temp

May-14 Dam Level 1214 Jun-14 Dam Level Dam Level Jul-14 Dam Level Aug-14 Dam Level Sep-14 Dam Level Oct-14 Dam Level Nov-14 Dam Level 1209 Dec-14 Dam Level Jan-15 Dam Level Feb-15 Dam Level Mar-15 Dam Level Apr-15 Dam Level Shutter Position 1204 0 5 10 15 20 25

Temperature (Deg C)

WATER REPORT 2014 – 2015 COMPLIANCE