Xeriscaping principles and water conservation practices

Xeriscaping: A Great Way to Save Water and Money

While many Americans are more concerned about the increasing scarcity of oil supplies around the world, the harsh reality is that water is far more valuable than oil and it is becoming even scarcer as aquifers are depleted and the global human population continues to grow. Indeed, some indication of this scarcity is reflected in ongoing disputes and even wars over water in some parts of the world, and fully two-thirds of the world's population remains without access to clean water supplies. Further exacerbating matters is the manner in which the vast majority of Americans use water. Besides their daily use needs, Americans use enormous quantities of water to maintain their yards, golf courses and other landscaping features in ways that would make the rest of the thirsty world shake their heads in collective disbelief. In this environment, identifying better ways to conserve water represents a timely and valuable enterprise, and xeriscaping has been shown to provide a viable alternative to current water use methods. This paper provides a review of the relevant literature to explain was xeriscaping is, how it can be used to conserve water usage by consumers and the fundamental principles that are involved. A summary of the research and salient findings are presented in the conclusion, and an example of how xeriscaping techniques can be used in a representative yard is provided at the appendix.

Review and Discussion

A study by Vogel (2003) emphasizes that most regions in the United States have experienced the adverse effects of drought conditions in recent years, and climatologists caution that things are likely to get worse in the future as a result of global warming. According to Vogel, "In 2002, even the northeast portion of the continent got a taste of what water shortages can be like. By the early spring of 2003 approximately two-thirds of the U.S. was in some level of drought and most of the western U.S. And Canada was facing widespread crop and pasture losses, an exceptional risk of wildfire, and shortages of water in reservoirs, streams and wells" (23). Moreover, water supplies that have long been maintained in reservoirs have been exhausted to the point that is will require a number of years worth of above-normal precipitation in order to replenish them (Vogel 23). Being essential to life, water is clearly a valuable commodity but the world's population continues to increase while water supplies are being diminished. In this regard, Vogel adds that, "In fact, water supplies are decreasing in most areas as groundwater is mined, surface supplies are over-allocated or unavailable due to pollution, and drought continues to be a problem" (23).

Although some "new" sources of potable water may be developed through technologies such as desalinization, scientists at the United States Geological Survey stress that any significant new supplies will come from "conservation, recycling, reuse, and improved water-use efficiency rather than from ambitious development projects," and they caution that we "no longer can try to meet insatiable water demands by continuously expanding a supply that has physical, ecological, and economic limits." In order to stretch supplies, municipalities are urging that people change their habits to conserve water. A great place to start conserving is with one of the largest residential uses of water, outdoor watering (Vogel 23).

North Americans use more water than anyone else in the world. In the United States, residential water use amounts to approximately 26,100 million gallons per day, or 100 gallons (378 liters) per person. Residential water use in Canada runs a close second, at 343 liters per person per day.4 Approximately 31% of that water is used outdoors.5 This percentage varies greatly depending on the climate and season. The hotter and drier the climate, the greater the portion of household water that is used outdoors, and during the heat of the summer outdoor usage can spike to almost 70% of residential water use. While outdoor usage includes washing cars and filling fountains and pools, most of this water (85-95% of it) is used to keep our thirsty lawns and gardens green (Vogel 24). The origins of the term "xeriscaping" date to the 1980s when city leaders in Denver, a relatively arid municipality, responded to their rapidly increasing population by forming a task force to better manage the city's water resources that were being used for landscaping purposes. According to Vogel, "The task force came up with a plan for the wise use of landscape water in an arid region and called it 'xeriscaping' (xeri from the Greek word for dry, and scape meaning vista)" (24). Consistent with the need to conserve water, an increasing number of developers have used xeriscaping for new construction projects as well as adapting existing properties where water conservation is a priority to this use (Vogel 24). Not only is water being saved using xeriscaping, but consumers and businesses can save money in the process as well. For instance, according to Hepner (2006), "In a nutshell, xeriscaping is drought-resistant landscaping. It can shave dollars off your water bill and hours off your gardening chores and produce gardens that survive August" (4). Drought-resistant does not necessarily mean dry, brown and unattractive, either. For example, an early article in the Journal of Property Management (1993) emphasizes that, "Xeriscaping, a practice that utilizes native plants and trees, allows managers to create lush and attractive landscapes that require a fraction of the care and watering of more typical commercial lawns and plantings" ("Landscaping to Conserve Water" 20). Rather than using traditional lawns comprised of various grasses, shrubbery and flower beds with clearly defined border using nonnative plants, property owners have enjoyed good results landscaping with native plantings including tall grasses, wildflowers, and other foliage that is less demanding in terms of maintenance and water requirements ("Landscaping to Conserve Water" 20). Water needs are reduced because plants that are native to a region typically require a great deal less water. In this regard, the editors of the Journal of Property Management add that "Because they have evolved to survive in a particular climate, they typically are able to support themselves on existing, available water supplies. Contrast this to the needs of the European and Asian plants -- including turf grass -- that require almost constant watering (not to mention mowing and chemical fertilization) to survive and retain their pleasing greenness" (20). Moreover, native plants are generally hardier than their nonnative counterparts, and are capable of enduring the temperatures, arid or wet conditions, and pests in their native climate without the need for heavy applications of pesticides and herbicides that non-native species require ("Landscaping to Conserve Water" 20). In addition, native plants can help reduce or even eliminate the runoff and erosion that characterize many regions of the country where nonnative plants have been extensively used, and can help replenish underground reserves by allowing water to percolate back into the earth ("Landscaping to Conserve Water" 20). Although xeriscaping can be used in any region of the country, the southern states are especially well suited for its use. For instance, more recently, Wheeler (2004) notes that, "The notion of limits applies as well to water use, especially within arid or semi-arid areas, and may mean planning for extensive water conservation and recycling. In fact, such steps are already bringing about a transformation of landscaping practices in parts of the southwestern U.S., where concepts such as xeriscaping - landscaping using drought-tolerant, often native vegetation - are taking hold" (39).

By some accounts, the use of xeriscaping is used predominately in commercial settings. For instance, in his book, An Environmental History of the World, Hughes (2001) reports that, "The urban forest is undergoing ecological succession, and it is not always the succession people want. A program aimed at reversing the trend is xeriscaping: landscaping with plants that require less water, especially High Plains natives that can survive on rainfall. Although xeriscaping is still rare on residential streets, new corporate buildings have used it" (216). While commercial developers may readily embrace landscaping techniques that save water (and money!), homeowners may be less enthusiastic about the concept unless they are convinced that it is in their best interests to make the initial investment to save money over the long-term. In this regard, Norton (2002) reports that awareness of the need to conserve water may help change a lot of people's minds, especially if they are aware of the true costs associated with their water consumption practices: If the full costs of irrigated lawns, including damage to wildlife, stream-water quality, etc., were paid by customers, they might turn off the spigot and 'suffer' with a brown lawn. The difference between charging full costs and changing preferences is that in the former case, consumers end up feeling deprived and unhappy, whereas they may feel enlightened and happy after being educated about the joys of a xeriscaped lawn" (264). Old habits die hard, though, but as more and more consumers embrace the concept of xeriscaping, Norton suggests that others may follow suit. In this regard, Norton points out that, "Once xeriscaping becomes an element of the community's identity, and citizens encourage a change in the tastes of their neighbors, a trend toward less water use and more native habitat might build on itself, providing increasing returns on a small investment. Investments such as this could pay increasing returns in lowering per capita demand for scarce resources and buffer the economy against shortages and rising prices" (2002: 265). Likewise, Vogel reports that because the technique can help to save water in all types of climates, xeriscaping has become increasingly popular in many regions of the United States.

In reality, xeriscaping is not a mysterious or difficult process, but it does require taking several principles into account that can help reduce water usage. First and foremost, the area to be xeriscaped must be regarded as an interrelated network of soil, plants and water. Despite the fact that xeriscaped literally means "dry vista," xeriscaping does not mean that a lawn will consist of just rocks and cacti (Vogel 24). According to this authority, "Drought tolerant and native plants are favored, but, in addition, zoning is used to group plants according to their water needs. A small high-water-use zone allows a place for those favorite plants that need extra water, but eliminates excess watering of plants that do not require it" (Vogel 24). There are seven general principles involved in xeriscaping as described in Table 1 below.

Table 1

The seven principles of xeriscaping

Principle

Description

1. Planning and design

Xeriscaping starts with a good design that will help ensure that the landscape remains water-efficient and retains its aesthetic appeal over time. The physical characteristics of the site to be landscaped are considered, as well as how the site will be used and the aesthetic preferences of its inhabitants.

2. Soil improvements

Creating a thriving landscape requires knowing the site's soil characteristics, the needs of specific plants, and when and how to amend the soil for water retention and plant nourishment. Soils are quite varied, ranging from almost pure sand to heavy clay. The water-holding capacity of most soils is improved with the addition of organic matter such as compost, peat moss and animal manure. When landscaping with native plants, however, soil amendments may not be necessary. Some well-adapted xeric plants prefer soil that is not too rich. For these plants, loosening the soil is all the preparation that is needed.

3. Efficient irrigation

Designing irrigation zones and choosing proper irrigation equipment are the two key factors in efficient irrigation. In xeriscaping, areas of the landscape are designated as low-, medium- and high-water-use zones. Appropriate plants are then chosen for each zone and are given only the water that they need. Selecting the right equipment ensures that water is not wasted. Lawns, which are high-water-use areas, are best watered with sprinklers. Trees, shrubs, flowers and groundcovers can be watered efficiently with low-volume drip emitters, sprayers and bubblers. Great strides arc currently being made in the technology of irrigation, including such innovations as underground drip systems that deliver water directly to the roots of plants and minimize water loss due to surface evaporation and runoff.