Urban Water Sustainability Solution: Xeriscaping
According to a USGS (United States Geological Survey) data, in 2010, an average person in Utah used about 250 gallons of water per day. Among that, about 40% (or 100 gallons) was used for indoor use while 60% (150 gallons) was used for watering lawns. This is an alarming fact for the desert state of Utah, where rainfall is scarce. More than half of the water which has been carried through an expensive system of reservoirs, pump stations and miles of pipeline, is sprinkled into the lawn to keep it green. With population of Utah expected to double by 2050 (2005 Economic Report to Governor), additional demand for more houses and more lawns would require more sources of water and additional infrastructure. This begs the question – Is it wise of us to expect green and lush outdoor lawns all year round, in the middle of desert using one of the most important, limited and expensive resource? Can this use of water, which works against the environment of the place, be supported by a sustainable water system? No. This would not help for a sustainable water system, where we can meet the present needs without compromising the needs of future generation. To have a sustainable system, it would be much sensible to work with the environment rather than working against it. So, one of the solutions for a sustainable urban water system is the replacement of non-native ever-thirsty plants to create a landscape with plants which live in harmony with the local environment and use much less water, which is commonly known as: Xeriscaping. This article starts with a brief introduction about xeriscaping, common myths, benefits and how it can be a sustainable solution for urban water management.
What is Xeriscaping?
Xeriscaping is derived from the Greek word ’xeros’ which means dry and the word ‘landscaping’. This method of landscaping refers to use of low water using plants to conserve water but still preserve the attractiveness of the place.
How does Xeriscaping work?
The seven main principles on which xeriscaping is based are – (1) Plan and design for water conservation – such as mapping areas in the lawn where there is sun exposure, direction of wind, shades, slopes, rain gutters, etc. (2) Improve the soil by testing – e.g. if it is very loose, treating it appropriately by adding organic matter and if it is very dense adding sand/gravel to loosen it. (3) Trying to limit turf area as much as possible or select other alternatives which are best at conserving water and are most drought-resistant (4) Installing an efficient irrigation such as drip irrigation rather than sprinkler system to avoid over-watering. (5) Appropriate selection of local plant species so that they look attractive which are easy to maintain and also takes up least water (6) Adding mulch on topsoil so that loss of water through evaporation is reduced (7) Seasonal and smart maintenance of the landscape such as pruning before the weather gets hot and dry (in winter) which can reduce water uptake during the growth stimulated by pruning.
What is NOT xeriscaping?
Xeriscaping has had a bad reputation because it is misunderstood by many. Experts from horticulture program in Colorado State Universityi state that there are major misconceptions regarding xeriscaping which has prevented people from replacing their lawns with these low-water use landscapes.
Some of the common misconceptions are – (1) “Xeriscaping uses only cactus and gravel”. This is a common misconception since people relate only cactus to desert landscape. But there are many different, colorful and variety of plants which can be used to xeriscape. Also, the overuse of gravel can increase temperature and can increase water use compared to mulch created from barks. (2) “Xeriscaping is expensive and hard to maintain”. Since xeriscaping is not as common as green lawns, and is usually implemented by progressive households, possibly with higher education and as such higher income levels, who can afford a lot more than basic xeriscaping, it has given rise to this misconceptionii . As with any other landscaping, the prices can vary greatly based on how the end product looks. Also, since the plants are mostly selected based on the native landscape, less maintenance is usually required than traditional lawns. (3) “Xeriscape means no lawns”. This is also one of the common misconception which can be attributed to the naming of the word. Many people think that Xeriscape has “zero” in the word which makes them think Xeriscape is lawn-less. But one of the principles of xeriscaping is to limit turf size to a practical area or select a low-water use turf; NOT remove the entire turf.
Benefits of Xeriscaping: Is it a sustainable solution?
The primary benefit of xeriscaping is that it helps in conservation of water by reducing the amount of water for irrigation in gardens and lawns but still maintains the attractiveness of the environment around the house. This conservation of water saves consumer’s money especially during summer when not only water but power bills also peak. Additionally, it saves energy to pump this water to the consumer’s house. A studyiii done in Georgia showed that cost of “creating” water by promoting conservation was 1/20 th cost of getting additional water from a new source. This cost can be higher for a drier state like Utah and so conservation is even more important.
There are other benefits of xeriscaping in addition to conservation. Maintenance of xeriscape is easier and cheaper compared to traditional landscapes. The plants are adapted to the environment which causes fewer problems with disease or insects. Also, they need less fertilizers and water that reduces the frequency of which weeding and pruning is required. Studiesiv have showed that homeowners apply up to 10 lbs /acre of lawn pesticide in US and children are most vulnerable to these pesticides. Lesser lawn area means better and easier maintenance and less pesticides which equates to safer children. It is also estimated that about 800 million gallons of gasv is used to power lawn mowers in US, which can be reduced by reducing lawn area. The additional benefit of xeriscaping is that it can also promote biodiversity. There have been studies in Colorado which have shown almost 60% reductionvi in the number of honey bees, insects and bird population in 40 years, due to urban growth. Insects, butterflies and birds are dependent on the plants and flowers of the specific area and if these were replaced it would have a negative effect on biodiversity. So, having a landscape that is closest to the natural environment supports the native birds and butterflies. Xeriscaping, thus, can be considered a sustainable solution for urban water management since it uses less water as well as it is easy to maintain, it is a healthier alternative which also promotes of natural biodiversity and provides aesthetically pleasing landscape.
If I decide to xeriscape, will it have any significant effect on water system?
Recent studies in Californiavii have showed that an average household can save 44 gallons of water a year by removing one square foot of grass from their lawn. Since the climate of Utah is drier than California, it can be expected that more than 44 gallons could be saved. So, if we could remove irrigated grass from 400 sq. ft of area, we could provide for almost 50% of indoor water use for a person for a year (based on indoor use of 100 gallons per person per day). Although these calculations are based on complete removal of grass, we could implement less severe alternatives such as changing turf grass to low water use grass and reduce water use for the entire lawn and obtain similar or even better results. These numbers show that since outdoor water use is a lot more than indoor water use, even a small change relating to outdoor irrigation can save considerable amount of water which can be used indoors and it can have significant effect on water systems.
Xeriscaping can be considered a sustainable solution to an already stressed urban water supply system in Utah. To have a sustainable water supply system, we need to change our attitudes and think about how we can live in harmony with the environment we are in, so that we do not compromise the needs of future generations. We have to make a choice – whether to keep our lawns green all year round and put the burden of a new and expensive water project to future generation or learn to live smartly with nature and start a new sustainable practice to conserve water.
Sources:
[i] http://www.colostate.edu/Dept/CoopExt/4dmg/Xeris/xeris1.htm
[ii] Jim Tolstrup (director of Loveland's High Plains Environmental Center) youtube presentation. https://www.youtube.com/watch?v=ELW-ULRCfh4
[iii] Why xeriscaping makes good Sense? Philip R. Karr http://www.slideshare.net/Eric832w/f2b556
[iv] Lawn and pesticide fact and figures http://www.toxicsinfo.org/Lawn/Lawn%20Pesticide%20Facts%20Figures.htm
[v] Xeriscape from the Ground Up https://www.youtube.com/watch?v=ELW-ULRCfh4
[vi] Audubon Society for Colorado http://www.slideshare.net/Eric851q/n2k588
[vii] 5 Water-Saving Ways to Replace Lawns During California’s Drought http://news.nationalgeographic.com/2015/05/150521-turf-terminators-xeriscape-california-drought-tolerant-lawns-water-savings/