Rain occurs when water vapor in the air condenses and falls back to earth.
But how does that water vapor get in the air in the first place? Half of it gets there by evaporating directly from bodies of water, like lakes and rivers.
The other half is put there by trees. This is because trees act like giant upside-down funnels. First, they absorb water from the soil with their roots. This water is then transported up through the tree to its leaves. From there, the water evaporates out of the leaves and into the air, as part of the process of photosynthesis.
This means that areas with lots of trees have more water vapor in the air than areas with few trees. When there’s more water vapor, rain is more likely to occur. Thus, trees affect precipitation patterns as well as temperatures.
Amazingly, this explains why rainforests are so rainy!
In the Eastern states, including Wisconsin, approximately 30% of household water usage goes to keeping lawns alive. Using water systems, or landscaping with plants that require less supplemental water, can greatly reduce the monthly utility bill.
In Western states, where up to 60% of household water usage is spent on lawns, water systems are often not legal. However, the desert states are home to a wonderful variety of drought-tolerant native plants. Landscaping with these species conserves water, reduces monthly expenses, and restores a unique sense of place.
Landscaping choices can affect heating and cooling bills too. A mature shade tree can significantly reduce summertime temperatures in a neighboring building, while letting sunshine in to warm the building in colder months. A row of trees or bushes can block winds that pull heat out of a home in winter.
In summer, even smaller plants that don’t provide shade can cool a home through their processes of exchanging water with the air. A yard full of healthy plants is like a green air conditioner!
Finally, a natural yard can often be cared for with minimal use of motorized equipment, which saves gas and electricity. Letting nature work for us can improve our comfort and quality of life, while keeping money in our pockets.
Water systems are methods for guiding the movement of water across a landscape.
In addition to soil type and pH, a spot’s site conditions are also described by how much water is present. The scale ranges from wet to dry, with moderate dampness often referred to as “mesic”.
Plants prefer different levels of moisture, and even a small yard can offer a variety of situations. Putting a plant in the right spot will help it to thrive without supplemental watering.
Changing the moisture conditions on a property can be as easy as moving a downspout. Pointing a downspout onto the driveway sends all the water collected from the roof out to the street, from where it goes directly to the lakes, along with any pollutants it picked up along the way. Aiming the downspout into a rain garden or other planting bed will keep plants happy, as well as safely filtering and storing pollutants.
A downspout can also be used to fill a rain barrel. A rain barrel is simply a container that stores water. The water can be used later to help plants through a dry spell. Along with being less expensive than municipal water, stored rain is also better for plants, which don’t like the chemicals commonly added to tap water.
A more advanced type of water system is a swale, a type of shallow channel that moves water across a landscape. This can be used to absorb water that flows down a hill, to spread out water that collects in a low spot, or to otherwise redistribute rain as it falls on a yard.
Water systems can add dynamic movement to a landscape, as well as allowing the property owner to maximize use of a valuable resource. As we will see in the next post, our yards can provide for us, rather than demanding constant expensive inputs. This is just one way in which natural yards bring wealth into our lives.
A rain garden is a planting designed to catch and absorb water, rather than letting it run off.
Rain gardens are typically sited in a naturally low or wet spot – the place where water collects during a heavy rain. They are constructed by digging a shallow pit, then adding plants that enjoy a moist location. A relatively small one can be built in a day, and requires little maintenance after that. Instead of having a mud puddle or a stream running to the storm drain, the homeowner can enjoy a profusion of flowers, along with the birds and butterflies the plants will attract.
Stormwater is filtered as it is gradually absorbed into a rain garden, instead of going directly to the lakes with any pollutants it may pick up along the way. While a rain garden holds standing water, it does not attract mosquitoes, which need at least ten days of standing water to complete their life cycles. A rain garden usually empties much faster than this, and in one that doesn’t, the problem can be easily remedied with the addition of an overflow drain pipe.
Madison encourages homeowners to establish rain gardens. The city’s website includes instructions and sample designs.
If you are lucky enough to live in Verona, the city’s rain garden rebate program will give you up to $150 to help cover the cost of plants.