13th August 2019

NSW MDB Porous and Fractured Rock Groundwater Status Update

MDB Porous and Fractured Rock Groundwater Status Update

• Groundwater Occurrence • MDB SDL Groundwater Resource Units • Number of registered works & bore

distribution • Measured usage against WSP and SDL

extraction limits. • Groundwater trading • Groundwater monitoring • Conclusions

The water cycle

Aquifer Types

Aquifer porosity

Porous rock vs Fractured rock

Conceptual model of groundwater flow

Gunnedah-Oxley Basin Cross Section –

Conceptual Model – Bioregional Assessment, 2018

Cross Section – Coolanbilla Mtn to Spring Ridge

Porous Rock - Number of Water Supply Bores in WRP Area

SDL Resource Unit Basic Rights Production Bores Local Water Utility Total

Gunnedah-Oxley Basin MDB 4100 283 5 4388

Western Porous Rock 759 54 3 816

Sydney Basin MDB 359 41 0 400

Oaklands Basin 0 0 0 0

Total 5218 378 8 5604

Porous Rock - Measured Usage, SDL and WSP LTAAEL extraction limits.

SDL Resource

Unit Groundwater

Source

Current LTAAEL (ML/yr)

New LTAAEL /

SDL volume (ML/yr)

Aquifer Access

licences (unit shares)

Water Utility access

licences (ML/yr)

Salinity and Water Table

Management access

licences (ML/yr)

Average Annual

Extraction (ML/yr)

Mine Shares

Gunnedah-Oxley Basin

MDB

Gunnedah- Oxley Basin

MDB 205,640 127,500 23,109 480 0 5,106 Coal

5,700

Western Porous Rock

Western Murray

Porous Rock 530,486 226,000 21,529 390 13,985 4,988

Yes, mineral sands

Sydney Basin MDB

Sydney Basin MDB 60,443 19,100 5,443 0 0 Not

monitored 0

Oaklands Basin

Oaklands Basin 0 2,500 0 0 0 Not

monitored 0

Information on the controlled allocation process is at:

Current Extraction Limit

Allocated Shares

https://www.industry.nsw.gov.au/water/licensing-trade/licences/controlled

Gunnedah-Oxley Basin Groundwater Source

New Extraction limit / Basin Plan SDL

Northern Fractured Rock - Measured Usage, SDL and WSP LTAAEL extraction limits.

SDL Resource Unit Groundwater Source

Current LTAAEL (ML/yr)

New LTAAEL / SDL volume (ML/yr)

Aquifer Access

licences (unit

shares)

Water Utility access licences

(ML/yr)

Average Annual

Extraction (ML/yr)

Inverell Basalt Inverell Basalt 25,807 4,150 3,382 0 324

Liverpool Ranges Basalt

Liverpool Ranges Basalt

MDB 19,075 2,160 422

0 57

Warrumbungle Basalt

Warrumbungle Basalt 5,710 550 71 0 No data

New England Fold Belt

New England Fold Belt MDB 204,784 39,253

55,100

9057 614 75

Peel Fractured Rock 71,218 15,847 11,008 548 998

Porous Rock - Temporary Trade 71T dealings Since 2012

SDL Resource Unit 2012-2013 2013-2014 2014-2015 2015-2016 2016-2017 2017-2018

Gunnedah-Oxley Basin MDB

1 trade (187.5ML)

4 trades (721ML)

5 trades (1059.5 ML)

3 trades (1062ML)

6 trades (1511.5ML)

6 trades (1196ML)

Western Porous Rock

1 trade (200ML)

2 trades (1160ML)

1 trade (900ML)

2 trades (300ML)

2 trades (2500ML)

2 trades (2500ML)

Sydney Basin MDB 0 0 0 0 0 0

Oaklands Basin 0 0 0 0 0 0

Porous Rock - Permanent Trade dealings since 2012

SDL Resource Unit 2012-2013 2013-2014 2014-2015 2015-2016 2016-2017 2017-2018

Gunnedah-Oxley Basin MDB 0 1 trade

(150ML) 1 trade

(206ML) 1 trade

(300ML) 2 trades (105ML) 0

Western Porous Rock 0 0 0 0 0 0

Sydney Basin MDB 0 0 0 0 0 0

Oaklands Basin 0 0 0 0 0 0

Drawdown and Bore Interference

Example hydrograph

Groundwater Monitoring

Gunnedah-Oxley Basin (Spring Ridge Management Zone): Site GW036333 Located approx. 11 km SSE of Spring Ridge.

Gunnedah-Oxley Basin (Spring Ridge Management Zone): Site GW036315 Located on Wilmots Rd approx. 15 km SSW of Spring Ridge.

Department Groundwater Monitoring

Site GW036972 Gunnedah-Oxley Basin

Gunnedah-Oxley Basin (Other Management Zone): Site GW036315 Located on Share Farms Rd approx. 11 km W of Willow Tree off Merriwa Rd.

Conclusions • The shares allocated in these water sources is generally well below

their extraction limit – this is due to low yields and varying water quality

• There is limited use of groundwater for irrigation, commercial and town water supply purposes

• Groundwater trading is very limited

• There is no concern for water level declines outside natural variations

• Groundwater extractions are significantly below extraction limits for all each of the 4 water sources

Questions?

Chris Rumpf

Groundwater Occurence

• When rain hits the ground it can generally either: • Evaporate • Runoff into a surface water system • Be taken up by plants • Provide moisture to the soil or the free draining system, or • Pass through the free draining system into the water table

• When it reaches the water table, it is now part of the groundwater system.

• This process is described as “recharge” • Groundwater flow is now governed by aquifer properties and

water quality is impacted by the host rock

Groundwater and aquifers

• Groundwater is stored in aquifers (water bearing formations), which are broadly classed as:

• Alluvial • Porous rock • Fractured rock

• The physical characteristics of an aquifer determine how easy and how much water can be extracted from the aquifer

• The chemical characteristics of the aquifer are imparted to the groundwater including salts, which can result in groundwater being too salty for an intended purpose

Aquifer types

Alluvial Unconsolidated material, generally associated with surface water deposits, usually containing fresher water quality due to a shorter water residence time. Typically units are recent to less than 1 million years old Porous Rock Typically associated with sedimentary basins, being made up of consolidated sediments, with primary and secondary porosity. Location of deposition can dictate quality of water, eg marine environment can impart salts. Typically units vary from 50 – 350 million years in age. Fractured Rock Typically any rock that does not contain primary porosity. Includes younger rocks such as basalts through to older metasediments and granites, as such units can be >600 million years old. Water quality and yields can be highly variable.

Department Groundwater Monitoring

Site GW036669 Western Porous Rock

Spring Ridge Geology

Spring Ridge Lots

Additional Fractured Rock Stats

Measured Usage, SDL and WSP LTAAEL extraction limits.

SDL Resource Unit

Groundwater Source

SDL volume (ML/yr)

LTAAEL (ML/yr)

Aquifer Access Share Component (unit shares)

Town Water / Water

Utility Share Component

(ML/yr)

Salinity and Water Table

Management (ML/yr)

Stock and Domestic

Access (ML/yr)

Average Annual

Extraction (ML/yr)

Adelaide Fold Belt (GS10)

Adelaide Fold Belt MDB 6,900 26,018 3,627 0 0 0 No data

Kanmantoo Fold Belt (GS19)

Kanmantoo Fold Belt

MDB 18,700 121,524 750 5 5 5 500

Lachlan Fold Belt (GS20)

Lachlan Fold Belt MDB --- 875,652 66,871 2838 236 0 4,244

Yass Catchment --- 26,163 2941.5 258 0 3 406

TOTAL 259,000 901,815 69812.5 3096 236 3 4650

New England Fold Belt (GS37)

New England Fold Belt

MDB --- 204,784 9057 614 0 0 122

Measured Usage, SDL and WSP LTAAEL extraction limits

SDL Resource Unit

Groundwater Source

SDL volume (ML/yr)

LTAAEL (ML/yr)

Aquifer Access Share

Component (unit

shares)

Town Water / Water Utility Share

Component (ML/yr)

Salinity and Water Table

Management (ML/yr)

Stock and Domestic

Access (ML/yr)

Average Annual

Extraction (ML/yr)

Inverell Basalt (GS18)

Inverell Basalt 4,150 25,807 3,382 0 0 0 324

Liverpool Ranges Basalt

(GS22)

Liverpool Ranges Basalt MDB

2,160 19,075 422

0 0 0 13

Orange Basalt (GS39) Orange Basalt 10,700 16,208

9,561

250 0 0 550

Warrumbungle Basalt (GS49)

Warrumbungle Basalt

550 5,710 71 0 0 0 No data

Young Granite (GS51) Young Granite 7,110 9,529 6,368 0 0 0 1,030