Turfgrass Use and Water Conservation
Fender, Douglas H., Landscape & Irrigation
In developed nations, we rarely feel the effects of the global water shortage. Local or state governments may urge us to use less water on our lawns in the summer, but that is usually as far as the inconvenience goes. But don't be fooled: the water shortage is real.
Ninety-seven percent of the world's water lies in oceans and seas, and two percent is locked up as glacial ice, leaving only one percent available for human use. Increasing population and water use have boosted water demand remarkably, while the availability of that one percent of usable water is reduced by pollution from industrial, commercial, agricultural and residential sources. The Futurist magazine issued this forecast in 1999: "Water scarcity could threaten one billion people by 2025."
Among other causes of water shortages:
* Development often outpaces infrastructure. Local water supply, treatment capacity or quantity can't keep up with the demands of new homes and commercial structures.
* Environmental concerns, regulations or legal decisions can restrict water availability.
* Drought and insufficient snowfall accumulation prevent replenishment of reservoirs.
* Flooding contaminates water supplies.
* Mechanical or structural shortcomings include leakage through broken pipes, which (in older water systems) can cause the loss of 50 percent or more of treated water. Water suppliers accept "unaccounted" losses of 10 to 15 percent of all treated water.
The Xeriscape movement
These examples underscore the importance of responsible water use by everyone concerned with plants and irrigation systems. Xeriscape, a concept developed in 1981, is quality landscaping that conserves water and protects the environment. Applicable worldwide, Xeriscape principles promote quality design that balances the lawn area, shrub and flower plantings and the hardscape. Xeriscape's mission is to convert professional and amateur landscape managers to believe in and practice proper water management, which provides the greatest opportunity for landscape water conservation. Properly applied, Xeriscape justifies the slogan, "Plants and irrigation systems don't waste water, people do."
Xeriscape's principles are planning and design, soil improvement, appropriate plant selection, efficient irrigation, mulching, appropriate maintenance and the use of practical turf areas. The last principle is the one receiving most of the attention.
Xeriscape's original idea about turfgrass was "limited turf use." Today's Xeriscape movement incorporates a more holistic approach, which recognizes that the human factor and landscape water management affect water consumption more than the type of plants used. Xeriscape focuses on turfgrass because of the tremendous potential for irrigation abuse in the name of maintaining green turfgrass.
In contrast to the initial Xeriscape perspective on turfgrass, Dr. J.B. Beard and Dr. R.L. Green conducted a study, "The Role of Turfgrasses in Environmental Protection and Their Benefits to Humans," published in the Journal of Environmental Quality. It provides strong evidence of turfgrass benefits.
In addressing water conservation, Beard and Green wrote:
"Trees and shrubs can use more water than turfgrass. Drought-resistant plants are not necessarily low water users. Adjacent trees and shrubs reap benefits of turfgrass watering. Turfgrass's brown color during drought periods is entirely normal. Low water-use turfgrasses can conserve water."
Just as Xeriscape principles can develop landscapes that conserve water using a variety of plants, they can also apply to the use of turfgrass alone. Some strategies include the following:
* Prepare soils for turf areas as carefully as any other planting area to use all available moisture, promoting the plant's vigor and water-use efficiency.
* In landscape zones, place turf species based on water requirements. …