Field drainage: Benefits and costs to farm businesses

Learn about the potential benefits of field drainage to the farm business and the costs of installation.

Benefits to the farm business

The benefit of field drainage varies considerably with climate, soil type and land use.

As a result, it is important to carry out assessments before installing or managing field drainage systems to identify the best approach for your farm business.

Land most likely to benefit

Production benefits from field drainage are usually greatest in high-rainfall areas or on:

• Heavy clay soils, especially in arable or intensive livestock systems
• Medium soils with potatoes, root crops or high-value crops
• Low-lying permeable soils where the groundwater level comes close to the surface

Fields with heavy or medium soils in heavy rainfall areas, springs or a naturally high-water table are most likely to have some form of drainage.

Reduced flood risk

• Reduced peak surface water run-off rates by increasing the availability of storm-water storage within the soil
• More balanced flow after storms, as rainfall percolates down through the soil into the drains
• Reduced flooding and soil erosion risks, not only within the field but also in the wider catchment

Improved plant performance

• Improved crop yield and quality
• More rapid warming of soils in spring − improving germination
• Improved environment for soil organisms
• Better access to water and oxygen for roots
• Better crop uptake of soil mineral nitrogen
• Decreased slug activity and reproduction

Better land access

• Reduced duration/risk of autumn waterlogging
• Quicker accessibility to fields following wet periods
• Crop inputs more likely to be applied at optimum time
• An extended growing and grazing season

Enhanced machinery efficiency

• Better traction
• Fewer cultivation passes
• Reduced draught forces
• Reduced wear and tear
• Fewer wet areas to avoid

Benefits to soil structure and the environment

• Less structural damage to soils
• Reduced frequency and extent of livestock poaching
• Better water infiltration
• Reduced surface run-off and erosion
• Potentially, reduced phosphorus and pesticide losses to water

Reduced risks to livestock health

• Reduced survival of parasitic larvae
• Snails carrying liver fluke do not thrive
• Reduced occurrence of foot rot and foul of the foot
• Improved udder hygiene for grazing stock
• Reduced risk of soil contamination during silage operations

Costs to the farm business

The cost of installing drainage varies greatly according to the scale and intensity of the system.

Based on 2024 prices, typical drainage costs per hectare are around:

• £2,500–£3,500 with permeable backfill
• £1,400–£2,000 without permeable backfill

However, drainage is a long-term investment. With good maintenance you can expect a useful life of at least 20 years (some systems can last many decades longer).

Potential funding options

Government-funded schemes may be available for a range of land management options and capital items.

These can help reduce the negative impacts of field drainage.

For example, funding options can be used to help create/improve wetlands, manage ditches and buffer water bodies.