Unregulated Diversions Water Outlook for Melbourne Water Licence Holders November 2017 Melbourne Water is owned by the Victorian Government. We manage Melbourne’s water supply catchments, remove and treat most of Melbourne’s sewage, and manage rivers and creeks and major drainage systems throughout the Port Phillip and Westernport region. Table of contents 1. Executive Summary ........................................................................................ 3 2. Introduction ................................................................................................... 3 3. Season to date & current streamflow ............................................................. 4 4. Climate Outlook .............................................................................................. 6 4.1 Average rainfall and warmer season ahead ........................................................... 6 4.2 Seasonal Streamflow Forecasts October – December 2017 ..................................... 8 5. Forward outlook for 2017/18 summer season ................................................ 9 6. Other factors affecting entitlement holders and the environment ................ 10 7. Further information ...................................................................................... 10 2 Unregulated Diversions Water Outlook for Melbourne Water Licence Holders | 1. Executive Summary Prevailing dry to average conditions through winter and spring this year has led to the early introduction of bans and restrictions within major catchments in the Yarra basin. The seasonal rainfall and temperature outlooks suggest Melbourne Water’s unregulated stream customers should anticipate high levels of bans and restriction commencing in early December and likely to extend to the end of the peak irrigation period in March / April 2018. Recovery of streamflows is likely to be slow without an influx of above average rainfall over several months. The outlook does favour chance of wetter than average rainfall but this is coupled with higher chances of warmer than average temperatures which will increase water demand. 2. Introduction The Minister for Water has delegated Melbourne Water with the responsibility for managing surface water licensing within the waterways and major drainage systems of the Yarra River, the lower Maribyrnong River, Stony, Kororoit, Laverton and Skeleton Creek catchments. Within these catchments we currently manage approximately 1300 licenses from waterways and administer approximately 500 farm dam registrations and licences relating to catchment dams. The total allocation issued under these licences is approximately 44,000 Megalitres (ML). The majority of allocation (41,700ML) is issued on catchments in the Yarra River basin, while the Maribyrnong and western catchments account for approximately 1,600ML and south- east catchments approximately 800ML. Water use is primarily for agricultural, industrial, commercial, sporting grounds and domestic and stock purposes. All licences managed by Melbourne Water are on unregulated systems except for a small number of licences in the lower Maribyrnong which are semi-regulated. The Water Act 1989 requires Melbourne Water to protect the environment and consider the needs of water users. Management of the water resource is achieved through a number of different mechanisms that include a Drought Response Plan (DRP), Stream Flow Management Plans (SFMPs) and Local Management Rule (LMRs). During drought or low flow conditions, licenced diverters’ access to water may be restricted or banned to protect the environment. Our Drought Response Plan is active at all times, and specifies how water is shared when there is not enough to meet all users’ needs. It states river flow levels which trigger restrictions or bans, and how these are applied to different licence types. These trigger points have been developed together with stakeholders in formulating stream flow management plans or local management rules. The status of restrictions and bans for individual catchments is posted on Melbourne Water’s website at www.melbournewater.com.au/diverters and is also available by calling Melbourne Water on 131 722 at any time. Individual catchment status is also available via an automated SMS services to subscribed customers. In addition the website will provide catchment specific stream-flow data including daily and 7-day average stream flow conditions. For additional licensing information and data please visit the website www.melbournewater.com.au/diverters. 3 Unregulated Diversions Water Outlook for Melbourne Water Licence Holders | 3. Season to date & current streamflow 2017 rainfall across the Yarra Valley, where the majority of licensed users are located, has been well below average in most months. Annual rainfall total to the end of November has been 615.0mm at Coldstream against a mean total of 674.2mm. The May-July period through winter proved particularly dry and translated to lower winter streamflows than expected. In ephemeral systems such as the Steels Creek and Dixons Creek catchments around Yarra Glen, this resulted in bans being in place across the entire winter-fill period for all but 5 days. Winter-fill licences in other catchments fared slightly better, particularly with a return to average rainfall conditions in the August to November period. Current flow conditions (as at 29 November) across all major catchments are tabled in the information below. On the back of the dry winter and average spring rainfall conditions, a number of the usually more reliable systems such as the Hoddles Creek, Stringybark Creek and Wandin Yallock Creek have already gone onto early bans and the Woori Yallock, Yarra River Upper and Yarra River Lower catchments are restricted. No. Bans / No. Bans / 7 Day Restriction Restriction Access to Flow Rolling Catchment days days - water (ML/d) Average 1/7/16 – 1/7/17 - (ML/d) 20/11/16 20/11/17 Arundel Creek Available 12.2 17.5 0 9 Cockatoo and Restricted 26.4 30.9 4 17 Shepherd Creek Darebin Creek Available 8.5 15.3 4 9 Diamond Creek Available 2.1 6.1 0 84 Dixons Creek Banned 0.2 8.4 80 139 4 Unregulated Diversions Water Outlook for Melbourne Water Licence Holders | Don River Banned 6.9 7.4 0 5 Gardiners Creek Available 5.1 37.9 6 1 Hoddles Creek Banned 3.9 4.3 5 56 Kororoit Creek Available 11.2 19.8 0 0 Little Yarra River Restricted 42.2 44.3 0 20 Maribyrnong River Available 31.7 57.6 0 0 (all year) Maribyrnong River Licence Ban 31.7 57.6 28 90 (winter-fill) McCrae Creek Restricted 8.4 9.8 4 87 Merri Creek Available 12.8 29.5 0 0 Moonee Ponds Creek Available 12.2 17.5 0 9 Mullum Mullum Creek Available 3.3 12.6 3 27 Olinda Creek (Lower) Available 17.6 23.4 0 11 Olinda Creek (Upper) Available 8.8 8.2 18 73 Pauls Creek Banned 0.2 0.6 111 143 Plenty River Available 3.9 8.1 0 4 Steels Creek Banned 0 0.5 106 141 Stringybark Creek Banned 2.2 3.0 0 65 (Lower) Stringybark Creek Available 2.3 3.0 51 84 (Upper) Wandin Yallock Creek Available 2.8 5.2 0 63 Watsons Creek Available 2.4 8.7 0 0 Watts River Available 15.3 22.6 0 0 Woori Yallock Creek Restricted 66.2 70.6 0 38 5 Unregulated Diversions Water Outlook for Melbourne Water Licence Holders | Yarra River Lower Restricted 581.1 665.5 8 39 Yarra River Upper Restricted 433.2 413.8 0 11 Restrictions and bans - www.melbournewater.com.au/diverters 4. Climate Outlook 4.1 Above average rainfall combine with warmer season ahead The Bureau of Meteorology seasonal climate outlook for the next three months shows no strong swing towards wetter or drier conditions for most of Australia. However, coastal regions of southeast Australia including Victoria are likely to have a wetter than average summer. There is a slightly wetter and warmer climate outlook across Melbourne & the water supply catchments for December 2017 - February 2018. The Bureau's ENSO Outlook is at La Niña alert, as the tropical Pacific approaches La Niña thresholds. Most international models maintain a weak La Niña until early autumn. Typically when the tropical Pacific cools towards La Niña levels, the western Pacific and seas around northern Australia warm significantly, but models suggest this is not likely to occur this summer. Likewise, La Niña periods typically see warmer than average waters develop in the eastern Indian Ocean. This season, near average to cooler waters are forecast to remain in this area, while warmer waters remain off Africa. The combination of ocean patterns, and the likely weak La Niña itself, is why Australia does not have significant and widespread increased chances of a wetter and cooler summer. Temperature and rainfall influence water use, especially during summer periods. At the same time, rainfall and temperature also influence catchment soil moisture levels and inflows to Melbourne’s unregulated waterways. Melbourne Water continually monitors flow conditions and the Bureau’s seasonal climate outlooks which are updated monthly. Rainfall outlook – The Australian Bureau of Meteorology outlook for rainfall (issued on 30 November 2017) for the period from December 2017 to February 2018 indicates December is likely to be wetter than average for Victoria with weakening chances moving into January. The map below provides Chance of above median rainfall for the December to February period: 6 Unregulated Diversions Water Outlook for Melbourne Water Licence Holders | Temperature outlook – The Australian Bureau of Meteorology outlook for rainfall (issued on 30 November 2017) for the period from December 2017 to February 2018 indicates that