Slowing The Flow, From Thunderstorm to River

Floods Aren’t New To The Sid Valley. But Storms Seem To Be Increasing As Does The Volume And Frequency Of Heavy Rain Events. These Storms Are Causing Increased Soil Erosion Leading To Blocked Drains And Deep Water On Some Roads.

Far more storm water than intended also enters the sewage system leading to Combined Sewer Overflows (CSOs) and subsequent raw sewage entering the river and onto our bathing beaches.

Across the valley landowners are implementing strategies to Slow The Flow from their land because soil erosion is not in their interest. Their efforts are not designed to prevent rain water entering the river, but to slow the rate at which it does.

So far, in the Sid Valley, over 120 leaky dams have been installed, in farmland streams and goyles, to slow the flow of water. Wetland areas have been created and swales are being built to encourage rain to soak into the soil rather than erode topsoil and flood downstream.

As one local resident said, “The amount of work carried out is incredible, in places it looks like beavers have been at work.”

Local farmers are to be congratulated on the way they are working with nature to create habitat that slows the flow whilst sequestering carbon and save our rivers and beaches from the extremes of fluctuating levels. Water that percolates in winter will slowly feed our streams and river during the drier times of the year, mitigating the worse extremes of drought.

UK gardeners can also implement several strategies in their gardens to prevent or slow down rainfall from directly entering drains and rivers, helping to manage water sustainably and reduce the risk of flooding and pollution. These methods often fall under the umbrella of Sustainable Drainage Systems (SuDS). Here’s a detailed breakdown of what gardeners can do:

1. Rainwater Harvesting:

Install Water Butts: The simplest method is to connect water butts to downpipes from roofs of houses, sheds, and greenhouses. These collect rainwater that can be used later for watering the garden, washing tools, or even topping up ponds.
- How it helps: Directly intercepts rainwater before it reaches the ground and drainage systems.
- Considerations: Choose the right size for your needs, ensure an overflow mechanism is in place (ideally directed to a soakaway or garden area), and use collected water regularly to create capacity for future rainfall. Some advanced water butts can slowly release water after a storm, further reducing drain overload.
Larger Storage Tanks/Cisterns: For larger gardens or more significant water needs, underground or overground tanks can store substantial amounts of rainwater. This requires more investment and space but offers greater water security.

2. Creating Permeable Surfaces:

Replace Impermeable Paving: If you have paved areas, consider replacing them with permeable alternatives like gravel, permeable paving blocks, or loose stones.
- How it helps: Allows rainwater to infiltrate directly into the ground, reducing surface runoff.
- Considerations: Ensure a suitable sub-base to facilitate drainage. Gravel areas can also help with infiltration.
Minimise Paved Areas: Opt for more planting beds, lawns, or mulched areas instead of extensive paving.

3. Enhancing Soil Infiltration:

Improve Soil Structure: Healthy soil with good structure absorbs water more effectively. Incorporate organic matter like compost and well-rotted manure.
- How it helps: Increases the soil’s ability to hold water and allows for better infiltration, reducing runoff.
- Considerations: Regular mulching also helps retain soil moisture and improve structure over time. Avoid compacting the soil by minimising foot traffic on wet areas.
Create Rain Gardens: These are shallow, planted depressions designed to temporarily hold and filter rainwater runoff from roofs or paved areas.
- How it helps: Allows water to slowly soak into the ground, filtering pollutants naturally.
- Considerations: Choose water-tolerant plants. The size and depth of the rain garden should be appropriate for the amount of runoff expected and the soil’s drainage rate. Direct downpipes towards the rain garden.
Install Soakaways: These are underground pits filled with rubble or designed plastic crates that receive rainwater runoff and allow it to slowly percolate into the surrounding soil.
- How it helps: Provides a direct route for water to infiltrate the ground, reducing the volume entering drains.
- Considerations: Ensure the soakaway is located away from building foundations. Soil needs to be permeable enough for it to function effectively.

4. Planting Strategies:

Increase Green Space: Lawns and planting beds naturally absorb rainwater. Maximize the vegetated areas in your garden.
- How it helps: Vegetation intercepts rainfall, and plant roots help create pathways for water to infiltrate the soil.
Use Mulch: Applying a layer of mulch around plants helps to slow down surface runoff and retain moisture in the soil.
- How it helps: Reduces the amount of water flowing over the surface and into drains.
Contour Planting: On sloping gardens, planting along the contours (across the slope rather than up and down) can slow down water flow and increase infiltration.

5. Directing and Diverting Runoff:

Disconnect Downpipes: Where possible and appropriate, disconnect downpipes from the main drainage system and redirect them to permeable areas of the garden, rain gardens, or water butts.
- How it helps: Prevents roof runoff from directly entering the drains.
- Considerations: Ensure the redirected water doesn’t cause damp problems in buildings or inconvenience neighbours.
Create Swales: These are shallow, vegetated channels designed to convey and filter stormwater runoff. They can be used to direct water slowly across the garden, allowing for infiltration.
- How it helps: Slows down the flow of water and allows it to soak into the ground.

6. Maintenance:

Regularly Clear Gutters and Drains: Ensure that gutters and any garden drainage systems are free from leaves and debris to function effectively.
Maintain Permeable Surfaces: Sweep permeable paving regularly to prevent the build-up of silt and debris that can reduce their permeability.

By implementing a combination of these techniques, gardeners can significantly reduce the amount of rainwater runoff from their gardens entering drains and rivers, contributing to better water management and a more sustainable environment. Remember to consider the specific conditions of your garden, such as soil type, slope, and the amount of rainfall in your area, when choosing which methods to adopt.