Landscape Architecture Resource

by Matthew Sandink

Water conservation appears to be becoming the new “Global Warming.” While there is always two or more sides to any argument, we should all want to conserve water as water is one of the two substances we absolutely cannot live without (the other being oxygen.) Water use reduction in the landscape is an area of water conservation where we can make easy changes now without any significant negative impact upon the landscaping industry. While it’s true that many articles written about the state of the environment tend to demonize one group over another, water is used and abused by every single group, company, country and individual in the world and the responsibility for it’s protection lies with all of us.

In landscape water use reduction, as in all water conservation, the focus is usually placed on mitigating the over-use of this precious resource without fully understanding the “other” problems associated with over watering.

Many of these issues directly affect the immediate landscape: plant death due to over-watering, damage to hardscapes and structures, and of course highly inflated water bills. The larger fallout of over watering in landscapes is a little harder to see without leaving the property.

Financial fallout

The link between energy use and water use is often referred to as “the energy-water nexus.” This references the fact that we cannot have healthy potable water in this day and age without costly water treatment. Associated with this process is the energy cost of pumping treated potable water to our businesses, homes and landscapes.

We must not forget, that for every drop of water running into the storm sewer on an over-irrigated landscape, that there is also an accompanying loss of energy. It is often argued that water is a renewable resource (certainly true) but the necessary energy used to treat water typically does not come from renewable resources. Some readers may be thinking to themselves; “I will never see these higher energy bills, so why should I care?” We must not forget that we are all taxpayers and residents wherever we live and water treatment energy costs, are carried by the already over-burdened taxpayer, you.

The issue of water treatment leads to another financial cost of water waste, municipal infrastructure costs. While there are ongoing studies with regard to this issue, enough data has been gathered to prove that many municipalities water infrastructure is designed around peak water use during the summer months.

Why would water use peak during the summer months? What’s so different about the summer? We water our turf and landscapes during that time period. Summer water peak demand is often 200%-400% higher than water demands through the winter months (extrapolated from data obtained from the OWWA – Outdoor water use reduction manual). Since the only unusual spikes in municipal water use occur during the summer months, it could be observed that city water infrastructure is being built to cater specifically to outdoor water use. By reducing our water use on landscapes to the necessary amount, many cities may not have to budget as much for infrastructure expansion. It is this expansion that is responsible for the rapid rise of water rates across Canada, and likely elsewhere.

Ecological fallout

Again, it is very easy to see how over-watering negatively affects our landscapes, but what happens when this water leaves the site?

In 2006/07 the city of Toronto initiated a program to disconnect residents downspouts from the sewer system. The reason for this is that storm water is running off of parking lots and landscapes during rain events and is picking up every hydro-carbon, chemical and salt and taking them, untreated, into the storm system and straight into our streams and rivers. Exactly the same thing happens when you over-water a landscape and it runs off into the street or storm sewers (and local streams.)

A very easy and logical estimate, knowing how many landscaped properties exist in Canada, is that more contaminated water than any rain event could ever produce, is running every day, during the summer, into our watersheds. This factor has only come to light in the last couple of years, however there are many years of data regarding agricultural run-off contaminating local ecologies.

In addition to agricultural studies, the Ontario ministry of the environment published the “Stormwater Pollution Prevention Handbook” which in addition to giving municipalities guidelines to mitigating water run-off pollution, also clearly identifies the sources of such contamination.

Today chemicals used in the landscape (by individuals, municipalities and contractors,) hydro-carbons and many other pollutants can be traced back (on a molecular level) to their source. It is only a matter of time before overwhelming data is published directly linking excess landscape irrigation as one of the greatest threats to our watersheds, lakes and rivers.

Finally, there is an unfortunate link between all three of previous issues that when you put it into perspective sounds completely absurd.

Not only are we damaging our local ecologies and environment with contaminated landscape irrigation run-off but we are also polluting costly treated water that we all have to pay for. This contaminated water drains back into the exact same sources we draw it from, we treat it again, and again it ends up right back on the same landscapes only to get contaminated and returned to it’s source over and over. This is not how the water cycle is supposed to operate.

Is any one person or group responsible? No, we are all responsible for our water; its pollution, its re-mediation and its conservation. There are many solutions to the above issues and many of the solutions are already being put into effect but it is up to each of us to recognize that we need to change the way we operate.

Matthew Sandink is the Conservation Solutions Specialist and is responsible for Marketing at SMART Watering Systems. SMART Watering Systems is a water conservation & rainwater harvesting consulting firm with it’s roots in the landscape irrigation industry.