Assessing your garden for Sustainable Rain Water Management:

When it comes to implementing sustainable rainwater management solutions, it’s important to first take a good look at your garden and consider a few key factors to figure out what will work best for your space.

There’s no one-size-fits-all approach—what works in one garden may not be the right choice in another.
So, before jumping into any projects, let’s go through a few things you should look at:

1. Space and Layout
The size and layout of your garden will be one of the most important factors in determining which rainwater management solutions are right for you.

• Where are the down pipes coming from your roof?
• Do you have access to them?
• How big is the roof area are they servicing?
• Is there an accessible drain located nearby?
• How much water do you actually need or want to be capturing for future use?

For example, a courtyard garden with lots of potted planting will benefit greatly from access to stored water.

A tiny courtyard space with no greenery or ‘gardener’ to speak of at the helm could install a rain planter and get growing!

Basically, if you have a downpipe it’s likely you can do something constructive. In fact, there are very few spaces that can legitimately say they can’t use one of these options!

On the other hand, if you have a larger garden you may have the space for multiple or, ‘chain of management’ type catch, slow and store features.

Example of 'chain of management' using rainwater features

A large garden could include rain planters, water butts and dipping tanks or, ultimately, nature-led, surface based options such as swales (vegetated channels that water can be absorbed into as it moves along) and rain gardens that they can lead to (which typically require more in depth assessment of site).
The above image shows an overflowing water butt releasing excess water across a paved channel into a nearby rain garden. Any excess water from the rain garden is conveyed to the grass area by a vegetated swale (a shallow channel with grass and/or plants lining it. Both the rain garden and swale provide opportunity for the water to soak into the ground below.

In addition and, regardless of the size of your space, if you have parking or paving, swapping what may be impermeable surfaces for a more permeable alternative that reduces run off and allows infiltration to the ground below can be an additional option.

2. Topography and Geology
Aside from considering the underlying geology (and how ‘absorbent’ it is ) you will also need to (literally) assess the lay of the land:

• Consider where rainwater currently flows in your garden:
• Do your downpipes go into the drain or, run off onto your garden?
• Is there an obvious slope or incline to the space?
• Does rainwater collect in certain spots or runs off towards the edges of your existing paving?
• Is there an opportunity to reduce the flow of the water across the surfaces of your garden?

This will help you identify design opportunities or where to install permeable paving to best slow, capture and manage the water or redirect the water to a more useful ends.

The type of soil in your garden also plays a role in how water is absorbed.
Clay soil tends to hold water and drain more slowly, which can be a challenge when managing excess rainfall (pure ground-dug clay can be used to created ‘puddled’ pond bases to actually keep the water in!)

If you have heavy, compacted soil, your ability to use features like rain gardens or permeable paving may be reduced or, need professional assessment in the first instance.

On the other hand, sandy or loamy soils allow water to drain through more easily and are ideal for run off to infiltrate.

However, regardless of your soil, rain planters and the above-ground storage options we’ve looked at are always an option.

3. Aesthetics and Garden Design
Sustainable rainwater management certainly doesn’t have to mean having to compromise on the beauty of your garden.
Over the years, words like ‘sustainable’ or ‘eco’ gardening has developed a bit of a bad reputation however, the tide is turning on more sustainable options for even those who like their gardens, dare I say it, on the tidier side of things...

Thankfully, at this point some of the most sustainable practices and features are being demonstrated centre stage at the likes of the Chelsea Flower Show.

The 2024 FloodRe garden designed by Ed Barsley and Naomi Slade was a wonderful example of an aesthetic garden and home integrated to deal with periodic, storm based flooding: https://www.floodre.co.uk/flood-resilient-garden/ )

Many of the solutions we’ve mentioned - rain planters, dipping tanks, and permeable paving—can be used to enhance the aesthetic appeal of your space.

Even the water butt market has had a make-over in recent years and there are many more available than your basic 200 litre, plastic barrel.
Think about how these solutions can blend in with your style of garden.

Consider how your garden is already laid out and how you want to use the space.

For example, if you’re working with a formal garden design, you might prefer neat, hidden water storage solutions like butts that can be screened or, make a pair of symmetrical dipping tanks a feature in their own right.
There’s no reason why you might not create a combined water feature and dipping tank in one.

For more natural or wildlife-friendly spaces, relaxed permeable paving and rustic, planted dipping troughs can help create a verdant look while supporting biodiversity.

4. Budget and Costs
Your budget will play a role in determining which solutions you can realistically implement. Fortunately, many sustainable rainwater management options are relatively affordable and can be scaled up or down depending on your budget.
For example, water butts are a cost-effective option that can potentially be easily added without much expense, while installing permeable paving or a large, off-the-shelf dipping tank might involve more upfront investment.

You can always start with a simple, small-scale solution that works within your budget, then expand or improve it over time. You can even look for second-hand or recycled materials for some features—like paving or rain planters—so you can keep costs down while still making a positive environmental impact.

5. Climate and Weather Patterns
It’s also important to consider the weather patterns in your area when choosing your rainwater management solutions and what your garden needs as a result.
If you live in an area that experiences heavy, regular rainfall, you may wish to prioritise slowing the flow of the excess water into your garden or, drains.

If you’re in a drier area or experiencing more drought-like conditions during drier months, rain planters and permeable paving can help manage smaller amounts of water and reduce run-off however, storage options like water butts or dipping tanks (covered to reduce evaporation) to catch and use the water that falls may be your preference.

Seasonal variation will typically work against you: Your garden will likely require more water during the summer months despite most rainwater typically (although not always a given) being available for collection during other seasons.

Finding ways to store water in a manner that keeps it useable, longer term may be helpful:

• For example, oxygenating planting kept prevents stored water going green
• Ensure your water is filtered of debris on arrival and sealed to prevent evaporation.
• During prolonged periods of heavy rainfall, find opportunities to empty the stored water in a constructive manner (watering a greenhouse or indoor plants which love rainwater compared to tap water, or, pots that don’t catch the rain properly. (I was told repeated at horticultural college ‘it doesn’t rain in pots!)
  Making space will ensure you make the most of the next deluge of run off.

By understanding local conditions, you can tailor your approach to maximize efficiency.

6. Ease of Maintenance

While there are lots of possibilities for improving rainwater management, it’s also practical to think about how much time and effort you’re willing to invest in maintaining these solutions (that said, none of these features require much more than a cursory, seasonal check in as you would any other element of your garden).

Water butts and dipping tanks may require occasional cleaning and ensuring the gutters and diverters supplying them don’t become blocked with leaves, while permeable paving needs to be kept clear of debris to stay effective.

Depending on the planting you’ve used, rain planters require a little attention to ensure plants are healthy and the water is being absorbed properly but another benefit of this type of management system is that any issues with water not moving through the planter correctly will be easy to spot.

Bringing It All Together
By considering these factors—space, layout, soil, aesthetics, budget, and maintenance, you can create a rainwater management plan that works for you and your garden.

In the next section, we’ll dive deeper into the mechanics of some of these solutions, but for now, take some time to consider your space and think about what will work best for you.

With a little planning and consideration, you can create a garden that’s not only beautiful but also resilient, sustainable, and better prepared for the challenges of a changing climate.