Follow the Drop – Rain
Rain
Since you’ve chosen to begin your journey as a drop of rain landing in the headwaters region of the Bow River, it is likely that you fell sometime between May and August as these are the wettest months of the year with average rainfall of over 30mm per month in places like Banff and Lake Louise1. Due to the rain shadow, created by the mountains, precipitation decreases as you move east from the Rocky Mountains towards the Alberta plains.
In the headwaters region where you landed, water quality is excellent with no significant contamination or minerals present. This is because when rain forms, it is generally quite clean. However, as water travels through the air, it can pick up pollution including car exhaust, dust or smoke, and microplastics 2,3 .
Fun Fact
Pollution: Acid rain occurs when precipitation collects acidic molecules and gases from air pollution and then falls onto the earth’s surface. Precipitation comes in the form of rain, snow, sleet, or hail.4
Definition
Rain Shadow: A dry area on the leeward side of a mountainous area (away from the wind). The mountains block the passage of rain-producing weather systems and cast a ‘shadow’ of dryness behind them.
Contamination: A substance that, in a sufficient concentration, will cause adverse effects to water, land, fish, or other things potentially rendering it unusable.
Microplastics: small plastic pieces less than 5 mm long that occur in the environment as a consequence of plastic pollution.
Where next?
During and after a rainy day, the resulting water either seeps into the ground to become groundwater, or it flows into the river system, increasing the amount of water in the river as well as in the connected streams and lakes. With these two options in mind, you need to choose your next step: Will you begin a meandering journey downstream by joining the upper reaches of the Bow River, or will you choose to seep into the soil and become groundwater.
References and Further Reading
- (n.d.). Retrieved from http://www.infobanff.com/info/?i=aw
- Uchiyama, R., Okochi, H., Katsumi, N., & Ogata, H. (2017). The impact of air pollutants on rainwater chemistry during “urban-induced heavy rainfall” in downtown Tokyo, Japan. Journal of Geophysical Research: Atmospheres, 122(12), 6502–6519. doi: 10.1002/2017jd026803
- Carrington, D. (2019, December 27). Revealed: microplastic pollution is raining down on city dwellers. The Guardian. Retrieved from https://www.theguardian.com/environment/2019/dec/27/revealed-microplastic-pollution-is-raining-down-on-city-dwellers
- Climate Change Canada. (2018, June 27). Government of Canada. Retrieved from https://www.canada.ca/en/environment-climate-change/services/air-pollution/issues/acid-rain-causes-effects.html
