Lot grading is the simple concept of creating a slight slope at the base of a home. This prevents rainfall from pooling at the edges of a house, which would then run the risk of seeping into the basement through cracks in the foundation, basement walls, or below-grade windows. Additionally, this kind of water pooling can contribute to stress on the municipal sewer system and lead to sewer backup flooding as well; which can be particularly damaging in a combined sewer system as household sewage from the entire neighbourhood can backup into a house’s basement. As climate change is expected to increase both the frequency and magnitude of high-intensity precipitation events, small but widespread changes such as effective lot grading can save many people from the hassle and expense of basement flooding. Edmonton has had in place a forward-looking and progressive flood reduction strategy since at least the 1980’s. The city has also enjoyed a strong and positive working relationship with surveyors, builders, and developers. This allowed for the City to work with those groups to create a lot grading enforcement strategy that is acceptable to all parties while still increasing the protection and resilience of Edmonton homes.
Recognizing that a changing climate is likely to bring more incidents of intense rainfall in the future, The City of Edmonton took the initiative to ensure that newly-developed lots are designed with grading to reduce the impact of rainfall-induced flooding. By legislating that a positive slope (the degree of which is dependent on the surface material) exist in all newly-developed lots, rainfall will be drained away from housing foundations and reduce the likelihood of basement flooding. This has been on ongoing process that, at its onset, met substantial political resistance but has persisted for decades and is evidence that climate adaptation is an iterative process that needs constant improvement and adjustment over the years.