Catching water in the landscape is in many cases more efficient than using rain barrels. Here’s how one suburban homestead used water from their roof to create a front yard garden.
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As the soil softens with rain in the spring and fall and there are cooler temperatures, it’s not a bad time of year to do some physically-demanding earthworks. When we tackled this front yard project, we were excited for it to jumpstart our edible landscape. We had no idea how much we would learn and grow in that garden!
Our Front Yard: Pre-Rainwater Project
In the years leading up to the front yard rainwater project, we had taken out the traditional yew bushes lining our front porch, and replaced them with four shade-tolerant currant bushes. We had also replaced some holly bushes with a black raspberry patch.
As we neared the 2011 garden season, we were feeling spunky and wanted to expand our edible front yard. We wanted to include a smart design that took advantage of the rainwater from the roof.
The combination of techniques used in a particular rainwater system will depend on the specifics of the locale: soil type and health, temperature, climate, slope, and budget and skill of the homeowner, to name a few.
Water availability is the most important aspect of any edible landscape or permaculture design. Why send rainwater to the sewer to muck up our rivers and fresh water ways, when we can catch and hold it on site to use for free irrigation?
Note: In Cincinnati we have what is called combined sewer overflow, which means that freshwater is combined with raw sewage during a large rain event and sent to our beloved Ohio River.
Allowing permaculture principles to inform our design process, we set out to create a closed-loop system that retained the rainwater from our roof on site and would hopefully reduce the number of times we have to drag out the hose and pay to water the garden with our time as well as money.
Best Place to Hold Water is….
In conventional gardening, rainwater catchment discussion usually focuses on acquiring a rain barrel or two. This sounds like an easy option that doesn’t take a lot of creative thought…until you go to water your garden that has expanded in size, and you realize how long it takes to use a watering can!
We decided to hold the water in the soil. Luckily, with a bit of physical labor on our part, it’s also the cheapest! It’s mathematically impossible to hold more water in a tank or barrel than in the soil, as soil can expand to 3 times its size to absorb water.
In the photo above you can see how the water naturally wants to run off the property to the right (blue arrows). The downspout is on the right side (west), but the majority of the new gardens will be uphill – to the left of it.
Our goal is to catch the rainwater coming from that gutter, and reroute it east – uphill. If our gardens had been downhill from the downspout (to the right of the gutter) our system would look completely different. Again it depends on where you’re catching water and where you need to take the water to, etc.
Goals of a Rainwater Catchment System
- Catch: Catch water onsite using earthworks and building up healthy soil. Healthy soil will not let any water run away unless it is completely saturated. Continually add organic matter to the garden beds – compost soil, manure, composted wood chips, etc. As the structure of the soil improves, the soil will improve its ability to regulate moisture levels. (See: 7 Ways to Improve Soil Quality).
- Hold: Hold water in the soil as much as possible. Mulching on top of the healthy soil with straw, leaves, and plants keeps the water from evaporating away, and allows it to slowly trickle into the deeper soil horizons.
- Recycle: Earthworks direct and store water underground, to be accessed naturally by plants during dry spells.
Our goal: Build a system that catches, holds, and recycles the water in the soil. Later we would like to add above-ground rain catchment in barrels, as needed. In the colored sketch above you can see how we planned to run water through the landscape that would provide a foundation for building future garden beds in the green space.
The front yard looked pretty ugly for a while as we dug and created this system. The neighbors were anxious! But the end result was totally worth it. Having a vision on paper that you’re working toward really helps you keep your eye on the prize.
Step 1: The Rain Chain
We disconnected the gutter and installed a rain chain. The rain chain is not essential, it just makes watching rain a beautiful event!
Post note: Be sure of your wind sector, i.e. from where does the wind blow? At our house, the wind blows toward the front of the house and splashes rain coming down the rain chain onto our porch. The rain chain would work better on the back of our house, or another protected area.
The rain chain guides the water down to a collection of rocks that discourages the water from splashing. The water is then directed into the conveyance trench.
Step 2: The Conveyance Trench
The conveyance trench was dug 12-inches deep and filled with gravel. It encourages the water to run away from the house, and down to the infiltration trench.
Step 3: The Infiltration Trench
The infiltration trench was dug 12- to 18-inches deep. It is filled with gravel, large rocks and a layer of wood chip mulch to double as a walking path. Infiltration trenches hold water until they can slowly soak (infiltrate) into the ground. In this case, the trench gets progressively deeper as it moves to the left (west to east) to encourage the water to run uphill to the rain garden, which will hold more of the water before soaking in.
Make the infiltration trench a walkable path! By filling in the trench with gravel or wood chips, the trench becomes a walkable path, which means more functionality in a small space.
Post Note: Wood chips are free and easily accessible, but if you can afford a complete trench filled with gravel, go for that. As the wood chips break down, the ability of the trench to absorb water is reduced. Another solution is to make the trench shallower and wider if space allows. It will hold the same amount of water, only in a different shape. A shallow trench is less of a hazard in a residential area, and it can easily be seeded with clover or grass, which may be easier to maintain.
We found 90% of the rocks we needed for pathways, borders, and filling the trench, from the rocks we dug out of our own yard.
Step 4: The Rain Garden
The rain garden is the final overflow catchment for the really rainy periods, where the water can be stored and slowly released into the lower yard areas. The rain garden is bowl-shaped, 12- to 18-inches deep and planted with native, deep-rooted, water-loving wildflowers like echinacea, aster, and blue-flag iris.
The year we built this system was the wettest on record. A berm on the bottom edge of the rain garden discourages overflow, but we discovered we don’t need this safety feature. The infiltration trench and asparagus berm work so well that water never pools up in the rain garden to the point of overflowing the rain garden berms.
The berms surrounding the rain garden were planted with edamame, swiss chard, carrots, and cayenne peppers in the first year.
Step 5: The Asparagus Berm
The asparagus berm was created by taking the topsoil from all of the trenches and piling it up on the downhill side. The berm absorbs the water from the infiltration trench and discourages water from running off our property. On wet properties, a berm offers a planting area above standing groundwater.
All of our garden beds surrounding this water system are covered in a deep mulch to discourage rapid evaporation and erosion of soil nutrients.
The deep-rooted perennials, like asparagus, also help to encourage absorption. Wild asparagus can often be found growing in ditches along roadsides, so I think it prefers this job of soaking up rainwater.
Post Note: Asparagus is a good choice for a berm because the roots can develop 10 feet deep. However, we made the decision that 6-feet tall asparagus wasn’t aesthetically appropriate to run through the middle of the front yard. (!)
So we removed the asparagus and replaced it with low-growing strawberry plants, also a good choice for a water system, since the roots can develop 6 feet deep. If this wasn’t a front yard design, I would still have asparagus! With both asparagus and strawberry, the important thing to note is that they don’t like standing water. They work on the berm because the yard is sloped, so water drains through the berm but doesn’t sit there.
As I mentioned earlier, this happened to be the wettest year on record for our area, so we couldn’t have planned the timing of a water system installation any better. If our system held up to this much precipitation, we’re confident it can hold up to anything!
The system is not entirely complete. There is still one downspout connected to the sewer. We would like to install an IBC tank to the right of our front porch, and direct its overflow into the existing conveyance trench.
This will give us another option for watering in times of drought. We also hope to expand the growing area of the front yard gardens.
Tips for getting started on your own design
Every design will be different based on layout, drainage, soil structure, etc. Observe how the rain runs on your property. Where does it pool up? Where is your preferred garden area? Remember, an imperfect design is better than doing nothing at all.
Ours wasn’t perfect, and I noted the adjustments that we made throughout this post, and ones that we will continue to make to our system in the future. The only golden rule is that you want the water to run AWAY from your house. Everything else can be tweaked as you observe.
- Gaia’s Garden and Rainwater Harvesting for Drylands and Beyond, Vol. 2 were the most amazing non-human resources we could’ve asked for while designing our system.
- A second opinion from a live, qualified person is a REALLY good idea. You never want to risk flooding your basement or that of a neighbor. (See: 3 Reasons to Hire a Permaculture Designer.)
Do you have an in-ground rainwater catchment system? What features does it have? What resources helped you plan your design? Has it needed improvement over time?