New South Wales Consolidated Regulations New South Wales Consolidated RegulationsThe following operational guidelines are to operate so that they do not contravene Parts V to XI of the Murray Darling Basin Agreement nor the intentions of that Agreement where they relate to the interstate sharing for the responsibility for the environmental management of the Murray-Lower Darling Rivers.
Note: Unless otherwise stated the flows noted in this section are provided out of combined resources as per the Murray Darling Basin Agreement.
Provide 1,850 GL per annum to the Murray at the South Australian Border
A total contribution of 1,850 GL per annum is provided to the South Australian
Border as per the Murray Darling Basin Agreement. This is a minimum flow and
is assented to by the Basin State Governments as well as the Commonwealth
Government. The plan is constrained by the need to provide the daily flows
indicated below.
Total Contribution to South Australian Entitlement
| Month | Monthly entitlement Total contribution (ML) | Daily flow at the South Australian Border (ML/day) |
| January | 217,000 | 7,000 |
| February | 194,000 | 6,929 |
| March | 186,000 | 6,000 |
| April | 135,000 | 4,500 |
| May | 93,000 | 3,000 |
| June | 90,000 | 3,000 |
| July | 108,500 | 3,500 |
| August | 124,000 | 4,000 |
| September | 135,000 | 4,500 |
| October | 170,500 | 5,500 |
| November | 180,000 | 6,000 |
| December | 217,000 | 7,000 |
| Total | 1,850,000 |
Additional Dilution Flow to South Australia
In 1987, as part of the MDBC Salinity and Drainage Strategy, it was agreed
that South Australia would be entitled to additional water to mitigate the
impacts of surface water salinity. This volume, known as additional dilution
flow, is only provided when the storage volumes in the Menindee Lakes exceed
nominated trigger points, at the same time the combined storage volume of Hume
and Dartmouth Reservoirs also exceed nominated triggers. The trigger volumes
within the Menindee Lakes vary between months.
When these trigger volumes are exceeded, South Australia is entitled to an additional flow of 3,000 ML/day, 1,500 ML of which is from NSW resource.
It is recognised that these additional dilution flows have contributed to the reduction in the impact of salinity. It is recommended, however, that these additional dilution flows be monthly totals rather than daily totals so that greater flexibility is available which can be translated into maximising both salinity and ecological outcomes.
Storage level triggers for additional dilution flow to South Australia
| Figures are ML | Jan | Feb | March | April | May | June |
| Menindee Lakes trigger | 1,300,000 | 1,300,000 | 1,300,000 | 1,300,000 | 1,300,000 | 1,650,000 |
| Hume/Dartmouth trigger | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 |
| Figures are ML | July | Aug | Sept | Oct | Nov | Dec |
| Menindee Lakes trigger | 1,650,000 | 1,500,000 | 1,300,000 | 1,300,000 | 1,300,000 | 1,300,000 |
| Hume/Dartmouth trigger | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 | 2,000,000 |
Minimum flows from Hume Dam
Minimum flows from combined resources are to be maintained out of Hume Dam to
ensure that down stream diversion needs are met, as well as for environmental
maintenance and water quality purposes. The minimum flows are currently as
follows:
(c) Minimum flows downstream of Hume Dam up stream of the Kiewa River are 600 ML/day.
(d) Minimum flows downstream of Hume Dam at Doctors Point are 1,200 ML/day.
Minimum flows downstream of the Curlwaa pumps on the Murray
Minimum flows from combined resources are to be maintained downstream of the
Curlwaa Irrigation District pumps on the Murray River during summer to ensure
that down stream diversion needs are met, as well as for environmental
maintenance and water quality purposes. The recommended minimum flow is 1,200
ML/day during summer.
(e) The rates may be reduced below their minimum recommended flows if river conditions are not conducive to the production of blue green algae as determined by the Department of Land and Water Conservation in consultation with the MDBC.
Minimum flows from Menindee Lakes to the Lower Darling River
In order to maintain appropriate minimum flow rates from the Menindee Lakes to
the Lower Darling River to maintain water quality and river health and
minimise the occurrence of algal blooms the following are recommended minimum
releases from Weir 32.
(f) The rates may be reduced below their minimum recommended flows if river conditions are not conducive to the production of blue green algae as determined by the Department of Land and Water Conservation in consultation with the MDBC.
Minimum recommended flows for the mitigation of blue green algae in the Lower Darling River
| Month | ML/day |
| Jan | 350 |
| Feb | 350 |
| Mar | 350 |
| Apr | 300 |
| May | 200 |
| Jun | 200 |
| Jul | 200 |
| Aug | 200 |
| Sep | 200 |
| Oct | 200 |
| Nov | 300 |
| Dec | 300 |
Using Barmah Millewa Environmental Water Allocation to Provide Flow to the
Werai Forest
Flows that are provided for flooding to the Barmah Millewa Forests under
environmental flow rule and which are diverted through the Edward/Wakool
system are to be managed to provide flood flows to the Werai Forest below
Stevens Weir where possible.
Acceptance of Rainfall Rejection Events
(g) NSW is to accept rainfall rejection events in the Murray River above the Barmah Choke every second year. NSW is to manage rainfall rejection events in the Murray River above the Barmah Choke in the year 2001.
(h) Victoria manages rainfall rejection events in the alternate years.
(i) NSW management of rainfall rejection is to mitigate the detrimental effects that such unseasonal flows would have on the forest ecosystems within the influence of the Barmah Choke.Winter Draw down of Stevens Weir Pool
(j) Maintain the Stevens weir pool at summer irrigation supply level until one week after the Easter school holidays,
(k) At the time the summer irrigation season demands are reducing, Stevens weir pool is to be drawn down in steps equivalent to reduction in demand,
(l) Weir pool draw down rates are to be no greater than 150 mm/day except where a greater rate reflects natural conditions,
(m) Weir pool reinstatement rates (rise) are to be no greater than 300 mm/day except where a greater rate reflects natural conditions,
(n) Unregulated flows into the Edward River are to be passed through Edward/Wakool river system alternately to the Wakool river and the Edward river down stream of Stevens weir.
(o) If unregulated flows have not occurred by mid August to raise Stevens weir pool, the weir pool will be raised slowly in accordance with irrigation season start up requirements using regulated supply.
Winter Weir Pool Manipulation-Rise and Draw Down
Where possible all weir pools, including Lake Wetherell, and Lock 9, along the
NSW Murray and Lower Darling rivers are to be managed for winter draw down in
a similar manner as that of Stevens weir pool, as relates to their specific
hydrology.
Rates of Rise and Fall
In order to minimise bank deterioration and unless natural conditions or other
environmental flows dictate otherwise the following rates of rise and fall are
to apply within the river channel.
i) Weir pools and Rivers, Streams and Waterways(p) Weir draw down rates be no greater than 150 mm per day except where a greater rate reflects natural conditions,(q) Weir pool reinstatement rates (rises) to be no greater than 300 mm per day except where a greater rate reflects natural conditions.
Lower Darling Flows from Menindee Lakes
(r) Where total storage volume in the Menindee Lakes will exceed 1,680,000 ML, flow release patterns should be implemented which provides a hydrograph of similar shape to that of a ‘natural flood event’, consistent with the protection of property as far as possible.
(s) Following extended periods of high flow greater than three weeks, apply the following recommended rates of reductions and monitor and record the effect of this action:
(t) For within channel flows greater than 20,000 ML/day downstream of Menindee, reduce at a
(u) similar rate of recession as occurred upstream of the lakes at Wilcannia.
(v) For flows greater than 10,000 ML/day and less than 20,000 ML/day, releases should be reduced at no greater than 1,000 ML/day each day.
(w) For flows greater than 5,000 ML/day and less than 10,000 ML/day, releases should be reduced at no greater than 500 ML/day each day.
(x) For flows less than 5,000 ML/day, releases should be reduced at no greater than 250 ML/day each day.
Menindee Lakes
Environmental flows for the Menindee Lakes are not included in this Plan.
Great Anabranch of the Darling River
The Great Anabranch of the Darling River is not part of this Plan’s area.
However, under an agreement between the Department of Land and Water
Conservation and the Great Anabranch of the Darling River Water Trust,
replenishment flows may be provided from NSW resources. Provision of supply
depends on the availability of adequate water and on there being a need for
additional water for domestic and stock purposes.
The present arrangements require a volume of approximately 50,000 megalitres per year. These may be replaced within the life of this Plan, with a likely option being a piped water supply system servicing landholdings along the Great Anabranch. Water would be pumped from the Darling and a licence or licences issued to secure the required water for the Anabranch landholders.