Case study: aquatic habitat and construction in St. John's, Newfoundland

A considerable amount of sediment is lost from building sites during construction. Depending on its location, this sediment finds its way to sewer or stream systems, increasing the costs of water treatment or impacting on aquatic habitat. In 1982, construction was started on a building to house the Institute for Marine Dynamics in St. John's, Newfoundland. The site, near the Rennie's River, required massive excavation. To minimize the impact of the sediment on the aquatic environment, a de-sedimentation facility was built. A settling pond was used, and alum was added to help settle the sediment, alum having no significant impact on the ecosystem. Without the de-sedimentation facility, toxic chemicals and sediment could have contaminated the fish, buried fish eggs, dislodged aquatic plants, and generally overwhelmed the aquatic habitat. Over three years, 1250 tonnes of sediment were kept from entering the river waters. The cost of the de-sedimentation was less that one tenth of one percent of the building costs, and a highly productive trout habitat was protected from contamination.

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