The quantity of water in an underground aquifer, stream, river, or lake, is important to ecological health and to the users of water.

In the Province of British Columbia, the consumption, or ‘beneficial use’ of water is regulated under the new Water Sustainability Act, which came into force in February of 2016. Prior to that, use quantities were licensed under the Water Act.

In the new Water Sustainability Act, regulators in the Water Stewardship Branch are tasked with ensuring that the total use of water is sustainable. Uses of groundwater, via wells, are now subject to licensing by volume just as surface water users are. Domestic wells are not affected by licensing requirements at this time.

The Water Sustainability Act also ‘holds back’ a quantity of surface water to ensure ecological health. Even in low flow, users of water must not bring water flows below a level determined as necessary for ecological health, an ‘environmental flow,’ or ‘e-flow.’

Most users of surface water — including domestic, or household users — obtained these licenses under the old Water Act. The new Act continues to ‘value’ these licenses in the same way. The oldest licenses have first priority on the use of the water in case of shortage. However, in areas where water shortages start to lead to conflict, the Act makes provision for Water Sustainability Planning. This part of the Act is not yet implemented.

Under climate change, significant changes to water quantity — especially to the timing of flows — are expected. We have seen this in recent years with record June rainfalls in the East and West Kootenays.