Irrigation System Design

The design and management of irrigation infrastructure plays a major role in determining water productivity. Fields, channels, storages and irrigation layouts should be designed to maximise water delivery efficiency, achieve uniform water application and minimise losses through runoff, deep drainage, evaporation and seepage.

Several irrigation systems are used across the Australian cotton industry, with the most suitable option depending on soil type, water availability, farm layout and business objectives.

Furrow Irrigation

Furrow irrigation remains the most widely used system in Australian cotton production and is particularly well suited to cracking clay soils. When designed and managed correctly, modern furrow irrigation systems can achieve excellent irrigation performance. Optimising flow rates, siphon placement, bay lengths and cut-off timing can significantly improve application efficiency and water productivity.

Centre Pivot and Lateral Move (CPLM) Systems

Centre pivot and lateral move systems allow water to be applied in smaller, more frequent irrigations to better match crop demand. These systems offer improved flexibility, labour savings and opportunities for precision water application, although energy costs and system capacity should be carefully considered.

Subsurface Drip Irrigation (SDI)

Subsurface drip irrigation can achieve very high levels of water productivity by delivering water directly into the crop root zone. While capital investment is significant, SDI systems offer precise irrigation and fertigation opportunities and can reduce evaporation losses when properly designed and managed.

Bankless and Siphonless Systems

Bankless and siphonless irrigation systems reduce labour requirements and improve operational efficiency by allowing entire bays to be irrigated simultaneously. Their success depends heavily on system design, field layout and management.

Irrigation Scheduling

Irrigation scheduling is about applying the right amount of water at the right time. Effective scheduling aims to match water applications with crop demand, avoiding both water stress and over-irrigation.

Modern irrigation scheduling increasingly combines multiple sources of information, including:

Soil moisture sensors and probes

Weather forecasts and evapotranspiration data

Remote sensing and satellite imagery

Crop observations and canopy monitoring

Tools such as IrriSAT and other decision-support platforms

Research and industry adoption have seen significant advances in irrigation scheduling technologies, helping growers make more informed decisions and improve WUE. Around 70% of Australian cotton growers now use soil moisture monitoring technologies as part of their irrigation management.

Storage Design and Maintenance

Well-designed and well-maintained water storages help maximise the value of every megalitre captured on farm. Storage location, design and operation all influence water losses through seepage and evaporation.

Regular inspection and maintenance of storages, channels and associated infrastructure can improve system performance and help identify issues before they become costly problems. Monitoring storage losses and water movement throughout the farm is an important component of whole-farm water management and irrigation efficiency.

Know your water position. Keep accurate records of water allocations, storage levels, rainfall, runoff, soil moisture and irrigation applications to support better planning, benchmarking and water budgeting.

Use data to guide irrigation decisions. Combine soil moisture monitoring, weather forecasts, crop observations and irrigation scheduling tools to apply the right amount of water at the right time and minimise crop stress.

Maintain irrigation infrastructure. Regularly inspect and maintain storages, channels, banks, pipes and delivery systems to minimise leaks, seepage and operational losses.

Monitor storage performance. Check storage capacity against original design specifications and maintain accurate depth-volume relationships so water availability can be measured with confidence.

Maximise irrigation efficiency. Aim for uniform water application and minimise losses to runoff, evaporation and deep drainage. In furrow systems, optimising flow rates and cut-off times can significantly improve water productivity.

Review your water budget throughout the season. Reassess available water, seasonal conditions and crop needs regularly so you can make informed decisions and direct water where it delivers the greatest return.

For more best-practice guidance, visit the myBMP Water Management Module.

Michael Scobie - Irrigation Technical Lead
0412 801 708
michaelscobie@gmail.com

New resources

Siphonless layouts & irrigation systems series: Siphonless Layouts & Irrigation Systems Series | CottonInfo

Smart irrigation for siphonless systems series: Smart Irrigation for Siphonless Systems Series | CottonInfo

The Irrigation Toolbox series

• The Irrigation Toolbox series - Overview | CottonInfo
  • The Irrigation Toolbox series - 1. Surface irrigation facts vs fiction | CottonInfo
  • The Irrigation Toolbox series - 2 . Improving furrow irrigation | CottonInfo3. Irrigation checklist
  • The Irrigation Toolbox series - 3. Irrigation checklist | CottonInfo5. Detailed irrigation record sheet
  • The Irrigation Toolbox series - 4. Irrigation record sheet | CottonInfo
  • The Irrigation Toolbox series - 5. Detailed irrigation record sheet | CottonInfo
  • The Irrigation Toolbox series - 6. Irrigation siphon size | CottonInfo
  • The Irrigation Toolbox series - 7. Theoretical flow rates for siphons | CottonInfo

Case studies

• GROWER CASE STUDY: Irrigation Conversion at "Norwood" | CottonInfo
• GROWER CASE STUDY: Irrigation Conversion at "Bellevue" | CottonInfo
• CONSULTANT CASE STUDY: Southern Irrigation Development | CottonInfo
• GROWER CASE STUDY: Irrigation Conversion at "Lynbrae" | CottonInfo
• Document

  DAN2303 Final Report_Water productivity benchmarking in the Australian cotton industry Dec 2025.pdf (3.98 MB)