Turns out that good top-soil is important not just for gardeners, but for city planners as well. Topsoil can provide valuable water conservation management services for cities. However, too much urban area is covered with pavement, compacted dirt and other surfaces that, unlike topsoil, do not absorb water well, if at all. As a result, complex rainwater management systems are required to collect rainwater; in fact, a number of B.C. cities have been sued – successfully - for flooding caused by development projects that were approved without adequate rainwater management planning.
To help local governments and designers make the most of topsoil, West Coast Environmental Law, working as a member of the Green Infrastructure Partnership, has released a two-part report - Topsoil: Just How Do You Obtain a Performing Topsoil Layer, to Advance Rainwater Management & Water Conservation Goals? The Cities of Surrey, Courtenay and North Vancouver are also part of the Partnership and have pioneered putting in place standards to promote good topsoil.
Here’s what the reports say about the importance of topsoil:
An absorbent topsoil layer has emerged as a fundamental building block for achieving water sustainability outcomes through implementation of green infrastructure practices:
- Rainwater Management: An absorbent topsoil layer serves as a sponge when it is raining, results in healthier landscaping, and contributes to sustainability of aquatic habitat.
- Water Conservation: Well-rooted landscaping requires less irrigation water, stays green longer during a drought, and contributes to sustainability of water supply.
The two parts of the report are directed at municipal staff and designers and include:
- A Technical Primer – This primer describes what good top soil looks like, how it functions and how to achieve it;
- A Law and Policy Primer – This part of the report discusses the laws and policies that local governments can put in place to promote and require the development of good top soil where possible.
West Coast Environmental Law co-authored this report, and we hope that it will be useful for local governments seeking to develop a more sustainable approach to rainwater and water conservation. Our work with the Green Infrastructure Partnership is part of West Coast’s Green Communities program, and builds on our 2007 publication, the Green Infrastructure Guide.