Rainwater Harvesting...

In Canadian cities, the average precipitation rate is between 260 to 1500mm per year. BC, Manitoba and Saskatchewan typically have higher annual rainfall than other Canadian provinces. During wet years with high annual rainfall, a lot of the water runoffs into local streams, rivers and watersheds. Alas, we are not effectively trapping this water and using it in productive and efficient ways. Rainwater harvesting is simply gathering, accumulating or storing rainwater.

Rainwater harvesting significantly alleviates the pressures placed on municipal water systems. Outdoor water use in particular, contributes to peak demand and puts pressure on infrastructure capacity. Irrigation for example, draws heavily from municipal water systems in times of high demand and low supply. Municipalities should promote decentralized infrastructure to harvest rainfall and create outdoor xeriscaped spaces that rely on precipitation for irrigation.

Like green roofs, municipalities can create incentives for rainwater harvesting to ensure developers of new buildings, subdivisions and residential units include water efficient landscaping from the start. The common fact and statistic associated with this technological phenomenon is this: in a dry climate with only 20 to 30 mm of monthly rainfall, rainwater harvesting can collect enough water to irrigate 25 to 40 square meters of lawn or garden area. This saves roughly 121 litres per capita per day. More importantly however, and similar to green roofs, rainwater harvesting improves urban stormwater quality, reduces erosion and flooding associated with high rainfall and reduces demand on centralized municipal water systems.

Key message: As a country with a relatively high annual rainfall rate, rainwater harvesting must be actively pursued. We need to take advantage of the precipitation that falls on our landscapes. Canadian outdoor water use in the summer time is profligate, adopting rainwater harvesting technology is more of a decentralized approach giving the citizen more independence. Ultimately, the more decentralized a water system is, the more citizens recognize the merits of water conservation.