eWATER SOFTWARE CONFERENCE 2017 MODELLING ENVIRONMENTAL WATER DEMAND IN eWATER SOURCE

Authors: Mahmudul Haque, Golam Kibria & Mahes Maheswaran

Presented by: Dr Mahmudul Haque, CPEng, NER Hydrologist, WaterNSW WaterNSW:

 We are Australia's largest water supplier

 We own and operate 42 large , pipelines and the state’s rivers

 We supply water to regional towns, irrigators, Water Corporation and local water utilities

 We develop infrastructure solutions for water supply security and reliability

 Website: http://www.waternsw.com.au/home

2 Outline:

 Macquarie Valley

 Environmental flow requirements

 Environmental flow rules

 Modelling in eWater Source

 Results

3 Macquarie Valley:  Burrendong = Koala

74000 km2

4 ENVIRONMENTAL FLOW REQUIREMENTS Environmental Water/Flow (in a year):  Two distinct types (Burrendong ):

1. Environmental Water Allowance (EWA)/Plan Water Total: 160 GL/year (not license, has GS characteristics) - 96 GL as translucent flow -If GS allocation is 28%, - 64 GL as active flow then EWA has same 28% allocation 2. Adaptive Environmental Water(AEW)/Held Environmental-It can also carryoverWater(HEW) water Total: 174.5 GL/year up to 100% as like GS - 48.5 GL as NSW purchase GS license - 126 GL Commonwealth Govt. purchase GS license

6 Environmental Water/Flow (in a year):  :

(i) The Macquarie EFRG sought and received approval for changes to the apportionment between Active and Translucent components from 40%/60% to 60%/40% in the mid-2000s. The releases from the Active component and any other held environmental water are typically made as recommended by the EFRG . (ii) Releases from the Translucent sub-allowance are generally consistent with WSP triggers.

7 ENVIRONMENTAL FLOW RULES WSP of Translucent Flow (Burrendong dam):

Conditions of release:

Amount of release:

9 Environmental Water/Flow (in a year):  :

(i) Planned environmental water releases: Sum of storage inflows plus tributary inflows downstream of the Dam is capable of producing a flow in the at Rocky Water Hole (421149) of at least 150 megalitres per day (hereafter ML/day) for 2 days or more. (ii) The rate of planned environmental water releases under subclause (2) shall be the lesser of: (a) storage inflow, and (b) the rate of release necessary to achieve 1,500 ML/day in the Cudgegong River at Rocky Water Hole.

10 Environmental Water (Windamere dam): (i) Release of planned environmental water from Windamere Dam shall not be made:

(a) when the storage level in Windamere Dam water

Constraints: storage is at or below 110,000 megalitres, or (b) after the total volume of water released under during any water year has reached 10,000 megalitres.

11 MODELLING IN EWATER SOURCE Modelling in eWater Source  Modelling has been done on the version: eWater Source 4.2.5

 Main two steps:

1. Assigning model variables 2. Writing function to release water

 Examples of Burrendong Translucent flow:  Modelled variables ✓ Inflow to Burrendong dam ✓ Trib flows (between Burrendong dam to U/S Marebone weir) ✓ Marebone flows for last 5 days ✓ Burrendong dam storage volume

13 Modelling in eWater Source  Functions  Trigger (when the set of rules fulfilled then release will be triggered):  Trigger is either 1 or 0, 1 means release will be triggered

if(min($mv_5_days_flow_at_421090) >=500, if($mv_Burrendong_vol_GL < 1188, 1,if($Trib_Flo ws <= 1000,1,0)),0)

 Release amount: if($EWA_Burrendong_Translucent_trig =1 AND $Translucent_date_range =1, min($Inflow_to_Burrendong_ML ,4500) ,0)

14 eWater Model:

Water User Node

Water Supply Node

Gauge

Link (between nodes)

15 Modelling in eWater Source  Assign the release function to the model physically

EWA_Trans_Water_User EWA_Trans_Supply_Node

Marebone weir (421090)

16 Modelling in eWater Source  EWA_Translucent Account has to be created in Resource Assessment

17 Modelling in eWater Source  EWA_Translucent Account has to be created in Resource Assessment

18 Result:  Water release from the Burrendong dam can be found in the “Results Manager”  Under “Results Manager” it can be found in the Water User Group, from there daily release flow can be obtained.

 Account balance and carryover can be seen: Results Manager19- Resource Assessment- EWA_Translucent. Conclusion:

 Environmental flow can be modelled through “functions”

 eWater has the flexibility to incorporate any environmental flow rules in the model

20