How can soils and aggregates stop flooding?

Whether you are a keen gardener who spends an hour each day out tending to your plants or are a farm owner making money from the crops you grow each year, the last thing you want is flooding.

To prevent flooding from happening when we have the typical British downpours, you should follow a seven-step plan that can improve the soil structure and reduce the risk of flooding.

Below are the seven steps you should take to avoid flooding. 

Minimise tillage

Tillage refers to the agricultural practice of preparing and cultivating the soil in order to make it suitable for planting crops.

When tillage is reduced, the soil structure tends to improve. This means that the soil has better aggregation, which allows it to hold more water. Well-structured soil with good aggregation can act like a sponge, absorbing and retaining water rather than letting it run off the surface and contribute to flooding.

Reduced tillage practices will also preserve organic matter in the soil, which will help improve soil structure, water-holding capacity, and overall soil health. Soils with higher organic matter content can absorb and store more water, reducing the volume of water that runs off and contributes to flooding.

Limit farm traffic

Limiting farm traffic to moving during dry periods and avoiding travelling when wet is also a strategy that can reduce flooding.

This is because farm machinery, such as tractors and combines, can exert significant pressure on the soil, leading to soil compaction. Compacted soil has reduced pore space, making it harder for water to infiltrate. When soil is compacted, it acts more like a hard surface, increasing the amount of runoff during rainfall. Limiting farm traffic can help reduce soil compaction, allowing the soil to absorb more water. 

Manage drainage

Properly managing drainage can be a crucial factor in preventing and mitigating flooding in both urban and rural areas.

Drainage systems will redirect water flow away from vulnerable areas, such as soil areas that are likely to flood.

Use cover crops, green manures and mulches

Using cover crops, green manures, and mulches can be an effective strategy for preventing and mitigating soil flooding in agricultural and gardening contexts. These practices offer a range of benefits that help improve soil structure, reduce water runoff, and enhance the soil's ability to absorb and retain water.

Cover crops, green manures, and mulches contribute organic matter to the soil as they decompose. The organic matter will help soils absorb more water reducing the amount of water running off the surface and flooding. 

Cover crops and mulches also create a protective layer on the soil surface, reducing the impact of rainfall on bare soil. This, in turn, minimises soil crusting and allows for better water infiltration. Water can penetrate the soil more easily when cover crops or mulch are present, reducing the amount of water that runs off.

Use grass leys to improve organic matter

Grass leys are essentially fields or areas planted primarily with grasses and legumes and help improve organic matter in the soil and contribute to flood mitigation.

As the legumes and grasses die, they add organic matter that enriches the soil and creates a better soil structure that will hold more water in times of heavy rain. 

Grassroots will also create a network in the soil, promoting soil aggregation and reducing compaction. This leads to improved soil structure, which will also enhance water infiltration and storage. You will probably have learnt by now that well-structured soil is better equipped to handle excess water, reducing the risk of surface flooding.

Use plants with large roots

Large roots create channels within the soil, improving its structure. These channels increase pore space and reduce compaction, allowing better infiltration. This will result in the soil being able to hold more water rather than the water running off the surface and creating a flood.

Plants with large, deep roots can also absorb water from deeper soil layers, which not only prevents surface water from accumulating but also helps recharge groundwater. This can be especially important during periods of heavy rainfall, as the plants help remove water from the surface, reducing the risk of flooding.

Try agroforestry

Agroforestry is a land management system that combines the cultivation of trees or woody shrubs with the growing of crops or the raising of animals on the same piece of land. It is a sustainable and integrated approach to agriculture that promotes the coexistence of trees, crops and/or livestock, often in a mutually beneficial manner.

Like most of these steps, the presence of trees and woody shrubs in agroforestry systems helps enhance soil structure. Similar to having plants with large roots, the tree roots create channels that will improve the soil's aggregation and increase water infiltration.

The trees will also be able to absorb significant amounts of water, which is helpful in wet periods that last a prolonged period.

Bonus tip

As well as following these seven steps, you can also use specific aggregates to reduce flooding in specific areas.

Drainage aggregates, often referred to as drainage stones or aggregate materials, are typically made of materials like gravel, crushed rock, or other porous substances. These materials provide a porous medium through which water can easily infiltrate the soil. When placed in or around areas prone to flooding, they allow water to penetrate the ground quickly, reducing surface runoff and the accumulation of standing water.

They can also store and temporarily hold excess water during heavy rainfall or flooding events. This controlled storage capacity can help reduce the risk of flash flooding by allowing for a gradual release of water, preventing rapid, uncontrolled runoff.

Help from MB Wilkes

At MB Wilkes, we are able to deliver a variety of drainage aggregates directly to your sites in Dorset. Whether you are looking for a large load for your farming fields or a small load for your garden, no order is too big or too small.

Get in touch with us today to discuss what you might need and how we can help. Call us on 01258 867465 or email us at [email protected].