A presentation at the WCCA 2011 event in Brisbane.

1. Bio-economic optimisation of land
use to manage natural resources
Iain Hume, Tom Nordblom, John Finlayson,
Hamish Creswell, Enli Wang
WCCA – Brisbane- 29 Sep 2011

2. Simmons Creek

3. A’
RYAN
0 5 km
Y
AR
UND
BO
NT
ME
CH
CAT
ALMA
PARK
MULLEMBLAH
HILL
Larundel
Swamp
ons Creek
MOUNT
ROYAL
Wiesners
Swamp
Simm
ek N
Cre CA
IR
ns UL
mmo To
C
Si
WALBUNDRIE
A Billa
bon
g Cr e MORGANS
ek LOOKOUT

4. 17,700 ha
35 farms
500 ha av size
9,000 t/yr salt load

5. Land use
Area (ha)
10000
7500
5000
2500
0
Low Med High Native Improved
Rotations Pasture Trees

6. Hydrology & water balance

7. Sub-catchments
2
1
4
3
5
6
11
8 7
10
12
9
13

8. Groundwater
Sub- Salininty
Catchment (mS/cm)
2 10 25,000
1
11 24,000
4
3 8 20,000
5 7 15,000
6
12 10,000
11
6 10,000
8 7
10
9 2,000
12
9 13 1,000
13

9. Change land use to reduce salt load
 How much and where?
 What?
 Is there a cost?

10. Estimating the water balance
APSIM (APSRU)
Simulations on each land unit
Plant biomass/yield
Plant water use & evaporation
Vertical & lateral flow of water
FLUSH (CSIRO L&W)
Water movement across land units
Water flow into channels

11. Agricultural Economics & Hydrology
Gross Margin
($ ha-1 y-1)
400
Gross Margin
($/yr) 300
200
100
Drainage
(mm yr-1)
0
100 Low Lucerne Pasture Lucerne Pasture Native Im proved
Medium Medium High High
Drainage 75 Rotation Pasture Trees
(mm/yr)
50
25
Run Off
0
(mm yr-1)
75 Low Lucerne Pasture Lucerne Pasture Native Improved
Medium Medium High High
Rotation Pasture Trees
Runoff
50
(mm/yr)
25
0
Low Lucerne Pasture Lucerne Pasture Native Improved
Medium Medium High High
Rotation Pasture Trees

12. Estimating Salt Delivery
 Linear Program
– Specified salt load @ Max GM
 Inputs
– Gross margin
– Drainage
– Runoff

13. Amount of change
12000
10000
Land Use Changed (ha)
8000
6000
4000
2000
0
9000 8000 7000 6000 5000 4000 3000 2000 1000
Salt Load (t)

14. Amount of change: sub-catchments
100%
10
75%
Land Use Changed
8
50% 7 2
9
4
13
25%
12 6
0%
9000 8000 7000 6000 5000 4000 3000 2000 1000
Salt Load (t)

15. 2
1
4
3
5
6
11
8 7
10
12
9
13

16. What to change

17. Cost
3
Farm income ($M/yr)
2
1
0
9000 7000 5000 3000 1000
Salt load (t)

18. Cost: sub-catchments

19. Will these changes happen?
 Probably not
– Wicked problem
– Inequity
– High cost

20. What did we learn?
 Policy tool to assess ES
 Scale matters
 Rural Social Research not an ‘add on’

22. Thanks
Simmons Creek Community
(Bernie Coyle, Hamish Ellis, Leon Kolhagen, Peter Wallis)
Murray CMA