Rainwater Harvesting for Drought-Resistant Buildings
Rainwater harvesting is a method of collecting rainwater for reuse on-site rather than allowing it to run off. In residential areas, effective collection requires a particular system or landscape to allow for either passive or active watering of lawns and gardens. This simple practice often saves homeowners money on their water bill, reduces stormwater pollution and flooding and allows people to better control their water usage.
Commercial applications work similarly, albeit on a larger scale. Builders and building designers can incorporate rainwater harvesting systems to reduce reliance on the main water supply and preserve conservation efforts in drought-stricken areas.
Why Water Conservation Matters in Building Projects
Rainwater harvesting has long been practiced by builders across the ages. Today, as climate change threatens many regions' water supply and resources, these practices are even more critical to the health and wellbeing of residents.
First, the population relies on water to sustain life — both due to drinking water and food production. Agricultural hotspots around the world rely on water supply to feed the population, but many of them are facing shortages in years to come. In India, the strain on the country's groundwater supply is set to become a crisis, as 90% of this water goes to agriculture. This is also a problem in wealthier countries. In the United States, California produces one-third of the nation's vegetables yet needs to import water from neighboring states to do so.
Secondly, communities without access to safe water for drinking and cleaning suffer in many ways. Malnutrition and dehydration are critical, but so are lost opportunities. In some regions of Africa, young girls and women are most likely to be sent several miles to collect fresh water. This means they lose out on education and employment opportunities every single day.
What does this have to do with the construction industry? Builders cannot solve the world's water crisis. What they can do is plan projects that take advantage of natural and engineered methods to conserve and recycle water. This reduces the strain on main water lines and groundwater, freeing up resources and making water available for other purposes.
Here are a few methods of rainwater harvesting that can be incorporated into residential or commercial building projects.
Smart Gutters and Downspouts
Ensuring water flows into a harvesting system is step one. Using gutters and downspout to harvest rainwater may be the most affordable and simplest solution for many households. All residents have to do is keep them free of sticks, leaves and other debris and make sure there aren’t any leaks in between seams. This way, the water will flow through the gutters, out the downspouts and away from the foundations of the home.
If water tends to collect around the base of a home, consider attaching downspout extensions to the gutters to direct water into the rest of the yard. Households may even be able to attach a drainage pipe to redirect water to a rain garden or nearby body of water.
Earthworks are another simple — albeit a bit more elegant — way to ensure that rainwater reaches landscaping and plants rather than the street or the building's foundation. By digging depressions and building small hills and slopes, landscape designers can redirect the flow of rainwater into the ground.
First, observe existing conditions and determine the natural flow of rainwater in a landscape. Where does water tend to pool or run off? Use machinery to level out the landscape or add new earthworks to redirect the flow. If designers still find water pooling in certain areas, build a rain garden to protect groundwater and support native plants and wildlife.
Is the building project in a climate with too little to moderate rainfall? Rainwater harvesting is still possible in drought-stricken areas with preparation. In these projects, plan to harvest rainwater by building a mulch basin. This option is one of the best ways to fix flash flooding and retain water while protecting the building itself.
Dig a shallow trench and fill it with mulch to create your basin. Then, use smart gutters or earthworks to redirect rainwater into this low-lying area. The wood chips will soak up the moisture and slowly release it into the earth as the soil drains. Thus, whatever landscapers plant in this mulch basin will receive a deep watering each time it rains. Trees and other plants with long, deep roots will typically thrive in these basins.
If a landscape slopes steeply away from a home, builders may consider creating terraces to aid in rainwater harvesting efforts. Hillside terrace gardens can be an attractive way to prevent erosion and evenly distribute and store rainwater. With terraces, each step will have time to soak in some water before it cascades over the next.
Builders and landscape designers might also add a retaining wall to further prevent erosion and promote water storage. As rain penetrates the soil at the top of the hill, it will soak down into the slope and act as water storage for plants living on each step. In times of drought, those with the deepest roots will draw upon this water and increase their chance of survival.
Barrels and Cisterns
Obviously, there are quite a few ways to water landscapes and gardens passively. However, if homeowners or facilities managers would rather use a hose or another manual system to water a landscape, they can instead consider buying or making barrels or cisterns to collect rainwater. These helpful storage solutions prevent flooding and runoff and allow residents to hold water for later use.
Attach a pipe or downspout extension to the gutters to direct water off the roof and into the barrel. Alternatively, one could build a cistern underground and siphon the water to this convenient storage spot. Then, hook up a hose and water whenever you wish. Just avoid using this water to grow edible plants as it may contain bacteria and pollutants from the roof.
Rainwater Harvesting Options for Building Projects
Drought-stricken climates need building projects to consider their usage of water. One relatively simple way to achieve conservation goals is to consider installing rainwater harvesting systems to recycle water for landscaping and other greywater applications. This can be applied to both single-family households and larger commercial projects.
From there, building professionals may find other ways to conserve water. From installing low-flow appliances to recycling greywater from facilities, there are various ways to save money and help the earth at the same time.