Example of the formation of rills and gullies on a rehabilitated slope 32 AVENUES WINTER 2019 AGGREGATES 101 E rosion is a word that carries with it many negative connotations. It comes from the Latin erodere, which means “to gnaw away” – a good description for this powerful force of nature. Aggregate producers have a rather complex relationship with erosion. On one hand, we provide some of the best tools for erosion control and protection, and our products do much to limit its impact. On the other hand, we are still subject to erosion’s relentless force and its detrimental effect at aggregate sites. It can create many chal- lenges for a site’s operation, particularly in terms of its impact on water quality. This can impact both active operations and reha- bilitation efforts at the end of a site’s extrac- tion period. For most people, erosion is a familiar process. At its most basic, it is simply a mechanism that results in the transportation of soil or rock particles from one location to another. Wind, for instance, can be an important mechanism for particulate trans- port, and the industry has a good history of dealing with dust issues. Most of the time, however, erosion is usually the result of water forces. Fine particulate, generated by erosion, can have serious impacts on water quality as well as the ecological function of water courses themselves. Rivers and streams naturally convey sediments. This fine partic- ulate transport can fluctuate over time and is influenced by geology, climate and terrain. Aquatic species living in streams have adapted to these cycles. Excessive erosion, however, is more serious and far more than just an eyesore. Water that carries eroded particles from human activities will cause reduced water clarity and can impact water quality. Tackling erosion There are many steps aggregate producers can take to minimize erosion – both at their sites and further downstream