By Kelly Feehan, UNL Extension Educator
Drought conditions have turned homeowner attention to water conservation. It is estimated that 40 percent or more of home water use is for landscape irrigation during the growing season.
In many cases, public water supplies treated to a minimum standard are used for lawn and landscape irrigation, but plants do not require water that has been treated to drinking water standards. Achieving these standards involves some form of treatment and the water must then be delivered to users through a distribution system, which can be an energy intensive process. Water softeners salts, fluoride, and chlorine found in treated water can also be detrimental to plants.
It is not a sustainable practice to continue using water treated to drinking water standards for non-potable uses like landscape irrigation. Following are some water conservation practices that can decrease the amount of treated water, and private well water, used for landscape irrigation.These practices involve making the best use of rainfall when we do receive it; and using good soil management practices that help increase and conserve soil moisture.
Harvesting and Using Rainwater
Make the most of rainfall by harvesting rainwater. Rainwater harvesting is the collection of rainwater by directing it to a planted area to soak into soil; or directing it into a rain barrel or cistern for temporary storage.
In most communities, rainwater is treated as a nuisance and is moved off developed sites as quickly as possible by street gutters and storm drains. Rainfall in Nebraska is more often sparse than abundant. This is all the more reason to make the best of it when we do receive it.
Rainwater doesn't all have to go down the storm drain. If more can be infiltrated into soil, the amount of irrigation needed will decrease. Deep, adequate soil moisture promotes healthy root systems that are more efficient at using available soil water.
Harvesting rainwater can be as simple as directing downspouts to planted areas; using small berms or drainage channels (swales) to direct rainwater to planted areas like shrub borders; to installing rain barrels.
While some rainwater soaks into lawns, turf soils are often compacted causing large amounts of rainwater to run off. With compacted soils and hard surfaces like pavement in urban areas, the use of rain gardens, bioretention basins, and bioswales installed specifically to collect and infiltrate rainwater are used to greatly increase the amount of rainwater infiltrated into soil.
Promote Water Infiltration
Proper management of lawn and landscape soils also increases irrigation and rainwater infiltration, increasing deep soil moisture. Increasing soil moisture conserves water by decreasing the frequency of irrigation, and water will be saved if adjustments in automatic irrigation timing are made. Focus on 1) reducing compaction by avoiding traffic on wet soils, 2) not working wet soils, and 3) core aerating lawns on a regular basis. Once a year is not too often to core aerate a lawn.
Amending soils with organic matter will increase infiltration of water on clay soils and improve the water holding capacity of sandy soils. Friable soils more readily receive rainfall so less goes down the storm drain.
Along with these practices, do not overlook selecting native and adapted plants that, once established, can survive on average rainfall. Also use a 2-4 inch layer of organic mulch around plants to reduce evaporative loss of soil moisture.
Population growth, climate change, and other factors are placing greater demand on fresh water supplies. This increased demand emphasizes the critical need to always use water efficiently; not only during times of drought.