6 Methods for Harvesting Rainwater

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Building your own water barrel is one method for harvesting rainwater that is sure to lead to a more sustainable urban homestead.
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"The Urban Homestead," authored by professed city dwellers Kelly Coyne and Erik Knutzen, is an illustrated guide that proposes a paradigm shift that will improve our lives, our community and our planet.

Written for city dwellers by city dwellers, The Urban Homestead (Process Media, 2010) is an illustrated instruction guidebook for the homesteading movement. Kelly Croyne and Erik Knutzen show how to grow and preserve your own food, clean your house without resorting to toxins and raise animals in your own backyard. This excerpt from “Be Your Own Utility”  gives six of the best methods for harvesting rainwater, as well as instructions on how to build your own water barrel.

After conservation, the second step toward water independence is harvesting rainwater. The number of ways you can go about this might surprise you.

Six Methods for Harvesting Rainwater

Rainwater harvesting is an easy and positive course of action for people in nearly every climate in the world. Living in a dry place such as the desert southwest may make it seem more urgent, but no matter where we live, rainwater harvesting is a positive step toward changing our attitude toward the water that falls for free from the sky. Rainwater can be sent to where nature intended it to go — to the soil.

The most important step in formulating a rainwater harvesting strategy is careful observation of present conditions. Where does water flow when it rains? Rainwater harvesting expert Brad Lancaster suggests working from the highest point in your yard to the lowest point. For most of us the highest point will be the roof of the house, but other high points could include sidewalks, decks, outbuildings, or your neighbor’s driveway. Observe where water goes in a rainstorm or when the neighbors overwater their lawn and ask yourself if there is a way to direct this runoff to where it will percolate into the soil and water your plants.

Rainwater Harvesting Technique 1

Become A Radical Depaver
Our first concern is to minimize the impermeable surfaces that prevent rain and earth from meeting. Your initial step in harvesting rainwater has nothing to do with barrels or pipes. Instead, you’re going to pick up a sledgehammer. In so doing you will eliminate, as much as you can, every impermeable surface that prevents rainwater from getting into your soil where it belongs.

Paving is convenient, but not healthy for the earth. Consider alternatives for any concrete or asphalt that is on your property: wood chips, un-motored brick, decomposed granite, anything that lets water seep through. These surfaces are more pleasant to walk on and look at than concrete, and they free up soil for planting. For instance, a driveway needs only twin tracks of stone, brick or concrete for the car wheels. The rest of it can be gravel or low-growing plants, and the edges of the drive can be lined with garden beds or trees. Less hardscaping in your yard means more water will percolate into the soil, and down into the water table.

Most concrete work will yield to a few swings of a sledgehammer. For densely-poured concrete you may need to rent an electric-powered jackhammer from a tool yard. A jackhammer is an easy tool to use despite its intimidating looks. Cradle it lightly in your hands (keeping it in a death grip will vibrate the hell out of your joints) and direct the chisel end at a slight angle so as to dislodge the outermost portions of the concrete that you are trying to remove. Using either a sledgehammer or a jackhammer, work from the outside of the concrete inwards towards the middle. Loosen broken concrete with a crowbar and pull it aside. If you have asphalt paving to remove, follow the same technique. It is softer, and so easier to pull out.

If you’ve got concrete poured next to your foundation you will want to leave some of it in place to prevent water from getting under your foundation or into your basement and causing expensive damage. To make a clean break between the concrete you are removing and a portion you may want to keep, you’ll need to cut a line in it. To cut concrete you have to rent a gas-powered concrete saw fitted with a diamond-edged blade. Your local rental yard should have one of these in either a hand-held or walk-behind version. You have to be careful to make sure that the blade does not go all the way through the concrete and into dirt. Dirt will strip off the diamonds and the rental yard may end up billing you for the replacement of the blade that can run into the hundreds of dollars. A concrete saw is a noisy and aggressive tool that needs to be hooked up to a hose to keep the blade cool. It makes a big mess and you’ll need to make sure to wear plenty of protective clothing — including eye and ear protection. There’s no shame in hiring someone if you don’t feel comfortable cutting concrete.

Chunks of broken concrete, sometimes called “urbanite,” can be used to make excellent raised beds and retaining walls. When breaking up your concrete, think about what projects you would like to use the urbanite for, and size it accordingly as you break it out.

One reason you should consider recycling your concrete is that it is expensive to get rid of it. You’ll have to pay to have it taken away in a special dumpster called a “lowboy.” The other reason is that the company that carts off the lowboy will do one of two things with your broken concrete: either stick it in a landfill or recycle it into yet more pourable concrete, exactly what our cities don’t need.

Any depaving at all is a step in the right direction. Nothing is more depressing than the millions of acres of concrete and asphalt that cover our urban environments, but at least we can deal with the little bits of concrete that we are responsible for.

Rainwater Harvesting Technique 2

Smart Gutters And Downspouts
Our roofs are another impermeable surface. We can minimize the surface area by living in as small a house as possible and trying to maximize open ground. At our own compound we’ve even gone so far as to remove an ugly addition, increasing the backyard space of our home. So-called green roofs, which have soil and plants growing on them, are an option for the wealthy, but at present are still rare in the U.S. Most of us will be dealing with conventional roofs.

Hopefully your roof has gutters. If yours doesn’t, it’s time to put some on. Gutters on the urban homestead channel water away from your foundation, and toward your crops. This is a job to hire out, as putting up a gutter can be challenging, especially when your roof is high up and professionals can fabricate seamless gutters, which are less prone to leaking.

Downspouts are the up-and-down pipes usually attached to the corners of a house that bring water from the gutters on the roof down to the ground. Having more than one downspout around your house will lessen the chance that any of them will get overloaded and will increase the possibilities for evenly distributing rainwater to your landscaping.

The bottom end of a downspout can be hooked up to a drainage pipe which carries the water away from the foundation and out to the yard. You can run these pipes above ground or below ground to anywhere you want water — to a mulch basin with plantings, for instance, which is described below. Drainage pipe is a white plastic pipe that comes in multiple sizes, with the most commonly used being 4″. There are a variety of fitting options for connecting them to your downspouts. You can find drainage pipe at home centers and lumber yards. See NDS Pro for examples of drainage pipe fittings.

Building codes requires that downspouts take water a minimum of ten feet away from a structure and this is a good rule of thumb to ensure that water doesn’t undermine your foundation.

Keeping It Clean
While we’re big believers in sloth and idleness, one task that absolutely must be performed at least once a year is to get up on a ladder and clean out the gutters. Otherwise, you will be attempting this task, as we know from experience, during a downpour at midnight, after the downspouts have clogged up sending a cascade of water over the damned-up gutters.

Two simple bits of technology can make gutter cleaning easier. We have inexpensive strainer baskets made out of 1/2″ hardware cloth in each of the downspouts to keep them from clogging up. You may wish to consider leaf guards which run along the top of the gutter to keep out leaves and other debris. The problem with leaf guards is that in order to clean out your gutters you must tediously remove the guards along the whole length of the gutter while balanced precariously on a ladder. While leaf guards catch large leaves, smaller stuff can still get through, so unless your leaf drop is monumental, you might as well just stick with the strainer baskets.

Rainwater Harvesting Technique 3

Earthworks are a simple, elegant way to ensure that rainwater gets to your plants rather than flowing out into the street. With an earthwork you shape the soil to catch and direct the rainfall into the ground. To build an earthwork all you need is a shovel and a sense of purpose. Basically what you are trying to do is to channel the water from roofs, sidewalks, driveways, steep hillsides, and other impermeable or semi-permeable surfaces to where that rainwater will nourish the roots of your plants. You do this by digging trenches and building up low earth walls to direct the flow of water.

The best way to design your earthworks is by careful observation of existing conditions. Even the most neglected of places will have plants growing where water naturally flows and collects. For instance, the drip lines of buildings, or low points near streets and sidewalks will often support a lush weedy landscape. Use these areas as your starting point. As a clever rainwater harvester your role will be to “hijack” rainwater and direct it to your plants.

Rainwater Harvesting Technique 4

Mulch Basins
One of the best ways of dealing with the sudden flood of water that a storm sends off a roof or that a washing machine ejects in a rinse cycle is with a mulch basin. Mulch basins are simply shallow trenches with raised walls that are filled with wood chips. You can direct rainwater or greywater in their direction via pipes, hoses or earthworks. They hold the water in one place until it can sink into the ground. The wood chips (the “mulch”) are there to help keep runoff from getting stinky, prevent evaporation and keep mosquitoes from breeding. Anything planted in a mulch basin will receive a good deep watering every time it floods, whether by act of man or nature. Mulch basins are particularly good places to plant trees.

If you’re clever and have slightly sloped land you can channel the overflow from one basin into the next so that when the first basin begins to overflow the water will spill into the next and so on. In other words, you will have a chain of basins.

An exception to mulch basin building is for people who live in excessively moist places. In these climates you will sometimes need to do the opposite — plant in mounds to keep roots from getting waterlogged.

Rainwater Harvesting Technique 5

If you have a hill on your property, water will cascade straight off it, and find its way to the street before it has time to sink into the soil. Slow the flow by cutting stair-stepped terraces into the hill. Support each “step” with a retaining wall made of stone, broken concrete or wood beams.

Slopes with terraces and retaining walls act as a water storage system. Rain penetrating the soil at the top of the slope forms a lens of water which over time migrates down through the hill. Plants with deep roots can reach into this lens and support themselves though extended dry periods.

Rainwater Harvesting Technique 6

Rain Barrels And Cisterns
If you’ve got more rainwater than your earthworks can handle or if you want to bridge gaps between rainfalls, one strategy to consider is using rain barrels to store water. A rain barrel doesn’t just collect water like a big bucket, it has fittings which allow you to hook up a garden hose to the barrel, so you can use your rainwater on whatever you wish, whenever you wish. You can purchase commercial rainwater barrels, or make your own.

How To Make Your Own Rain Barrel

The ubiquitous 55-gallon plastic drum makes an excellent rain barrel. The trick is figuring out a way to hook a hose up to the barrel. Often this is done with what is called a bulkhead connection, made by cutting a hole through the barrel and fitting a threaded pipe through it. The thing is, improvised bulkhead fittings have a tendency to leak. To make our rain barrel, we used instructions from a company called Aquabarrel which showed us how to use common PVC fittings available in any hardware store to hook a garden hose securely to the barrel. Aquabarrel also sells kits for a little more which come with all the fittings and a DIY video at aquabarrel.com.

With the Aquabarrel system you use the preexisting threaded bunghole fittings on the top of the barrel to hook up your garden hose, so be sure to get a “two bunghole” model when you’re buying your barrel. Once you’ve got the fittings installed, all you do is turn the barrel upside down on top of a couple of cinder blocks or similar for clearance, hook up a garden hose, and you’re ready to rock.

Another thing we like about the Aquabarrel design is the large overflow pipe and how easy it was to put together. You can even string several barrels together to increase storage capacity.

Have you been eyeing that unattended fruit tree in your neighborhood? Learn more about foraging with Tips For A Neighborhood Fruit and Nut Harvester.

Reprinted with permission from The Urban Homestead: Your Guide to Self-Sufficient Living in the Heart of the City by Kelly Coyne and Erik Knutzen and published Process Media, 2010.