Reconnecting irrigation with the river and ecological function of the catchment

CSIRO Sustainable Agriculture Flagship

Keith L. BristowCSIRO Land and WaterTownsville, Queensland, Australia

Natural capital - Social/cultural capital - Produced capital

It is not about balance – but choices and decisionsNo ultimate trade-off between the economy and environment

Environment Society

Economy ($)

BuiltInfrastructure

EcologicalInfrastructure

Complex inter-connected systems

(Area  770 million ha; Population 22 million)

“SUPPLY”

DEMAND

Pressure for protection and ‘sustainable’ use

Pressure for repair and ‘sustainable’ use

Great B

arrier Reef

Tropic of Capricorn

Brisbane

Broome

Carnarvon

Perth

Melbourne

Adelaide

Darwin

Victoria

NSW

Queensland

NorthernTerritory

SouthAustralia

WesternAustralia

Tasmania

Sydney

TownsvilleKarratha

Kununurra

Katherine

MDB

5

4

321

Australia - the big picture

67

The MDB

• ‘Excess demands’ on the environment got the MDB

into trouble…

• Opportunity to re-balance the system… But…

• Still want to drive the system harder and faster!!

The environment

• Does not function as a ‘business’!

• Catchments (ecosystems) reflect water flows – quantity, quality, timing, duration…and a myriad of other processes

• Complex systems characterised by feedback, non-linearities, lags, trigger and tipping points….

• Cautious about applying business/engineering principles; efficiency, growth, factor four improvements, trade offs…

• Need to maintain or reconnect irrigation with the river and ecological function of the catchment

• Need better understanding of and investment in the ecological infrastructure (elements, systems, services and the inter-connectivity between these)

• Water in the north is already being used- Decisions are about reallocating water to different uses and

understanding the implications

• Groundwater is critical to base flow and maintenance of ecological functions and processes

• Water quality is as important as quantity; especially in meeting ecological needs

• Efficiency is not the answer to everything- Need to meet multiple objectives; water, salt, nutrient …

• All irrigation needs an associated salt management plan

Key take home messages from northern Australia

• Must set and meet water table targets (both quantity and quality) and adjust management practices to meet targets

• Water management is an individual and collective responsibility

• Need policies and management systems that make sense for northern tropical environments (event driven systems)

• Short term economic gains are easy – it is the long-term sustainability that is the real challenge

Key take home messages from northern Australia

Complex interconnected systemsInland Coast

RIVERTurbid waters

Water spreading

Rootzone

Salt & nutrientbalance

SalinitySodicity

RisingGW

soil typeimpacts

ET

Salt water intrusion

Irrigation

GWdepletion

Irrigation

unsaturatedzone

Bores

ETRain

Leakageto sea

Drainagequantity/quality

Rechargepits

Recharge

Recycling

Monitoringwell

runoff runoff

SW / GWInteractions

Sea

Geohydrology and geochemistry impacts

Wetlands

Upwelling

Bores

• Dependent on the river system• Have changed the water and salt balance massively• Must set and meet water table targets (quantity and quality)• Individual and collective responsibility – MUST EXPORT SALT

Surfacewater

Unsaturated zone

Bores

“Contiguous”

RiverCoast

Rainfall ET

Roo

tzon

e

Groundwater system

Uns

atur

ated

zon

e

Surfacewater

Unsaturated zone

Bores

“Contiguous”

RiverCoast

Rainfall ET

Roo

tzon

e

Groundwater system

Uns

atur

ated

zon

e

Traditional largescale irrigated area

“Patchiness”

River

Bores

Groundwater system

Unsaturated zone

Coast

Surfacewater

Rainfall ET

Roo

tzon

e

Uns

atur

ated

zon

e

“Patchiness”

River

Bores

Groundwater system

Unsaturated zone

Coast

Surfacewater

Rainfall ET

Roo

tzon

e

Uns

atur

ated

zon

e

‘Mosaic’ structure

AdvantagesDisadvantages

?

Irrigation mosaics / agro-ecology

Profile

Catchment

Farmenterprise

Field

State /Region

MechanisticQuantitative

FunctionalQualitative

Scale dependent processes

Specialisation

Integration

BiophysicalBiophysical

Socio-economicSocio-economic

Country

Whole of system approach - System Harmonisation

• Definition: A strategy to improve cross-organisational communication and system-wide management to improve production and environmental outcomes in a whole of catchment context (Khan et al., 2008)

• Integrate science, policy, planning, management and communities...

• Working at the interfaces …environmental-social-economic…groundwater-surface water… land-ocean…

• Collaborative and transdisciplinary approaches

• An ongoing conversation…delivering continual innovation and improvement…

Significant opportunities for improved farm production

• A and D are representative points on the efficiency frontier for the best technologies at a point in time (▬)

• C and F are specific points on new efficiency frontiers for new technologies (---)

• Point B represents a position below the current efficiency frontier use

(Keating and Carberry, 2010)

The MDB

• Need a better long-term ‘engagement’ strategy

• Australian’s are investing considerable money in the MDB…

• All are aware tough decisions are involved…

• Must deliver an environmentally resilient and regenerative system for future generations…

Past technologies

• A and D are representative points on the efficiency frontier for the best technologies at a point in time (▬)

• C and F are specific points on new efficiency frontiers for new technologies (---)

• Point B represents a position below the current efficiency frontier use

(Keating and Carberry, 2010)

Investment framework - Production vs investment ($)

Pathway 1: Improve the agronomic performance of growers

Pathway 2: Encourage growers to adopt risk management practices

Pathway 3: Increase efficiencies of resource use

Pathway 4: Create new production frontiers

Pathway 5: Maintain current production potential

Based on John Dillon, 1977. An Analysis of Response in Crop and Livestock Production (2nd edition), Pergamon Press, Oxford

Involves integrating academic researchers with non-academic participants to research a common goal and create new knowledge, theory and practices

(Strong disciplinary skills working collaboratively with a wide range of stakeholders on complex problems towards a common goal)

Transdisciplinary approaches

The environment

• Biodiversity

• Ecosystem services

• Resilience

Irrigation efficiency – a flawed conceptNeed to be specific about how water used in irrigation

• The consumed fraction (essentially ET), comprising:- beneficial consumption (for the purpose intended or other

beneficial use such as environmental purposes);- non-beneficial consumption such as weeds or resulting

from capillary rise during a fallow period);• The non-consumed fraction, comprising:

- recoverable flows (water flowing to drains and back into the river system for possible diversion downstream, and percolation to freshwater aquifers);

- non-recoverable flows (percolations to saline aquifers, outflow to drains that have no downstream diversions or direct outflow to the ocean)

Key drivers

• ‘Empty’ to ‘full’ world… More with less!!

• Environment, water, food, energy...population…

• Complex inter-connected systems

• Peak oil, peak water, peak…

• Economic growth model…

• Competition (‘vested interest’) vs collaboration

• …….