Cleaning or maintenance of bridges or other structures

The cleaning, maintenance, or surface preparation of bridges or other structures. This may involve industrial cleaning or surface preparation equipment such as high pressure water blasters, mechanical sweepers and scrubbers, sandblasters, or any other technique or chemical product used to clean, strengthen, or prepare surfaces for additional processing or to refine or roughen surfaces to meet finishing requirements.

Effects

Change in sediment concentrations: Increased erosion of stream bank soils and rocks result in an excess of fragmented organic and inorganic material which is transported by water, wind, ice, and gravity. These sediments, which contain nutrifying elements and can capture or absorb contaminants, are suspended or else settle and collect in waterways affecting physical processes, structural attributes, and ecological conditions such as water clarity (by reducing visibility and sunlight and damaging fish gills) and reducing the availability and quality of spawning/ rearing habitat (through infilling).

Change in contaminant concentrations: An increase in concentrations of toxins and pollutants in sediments and waters can breach the range of chemical parameters that support healthy aquatic communities, seriously affecting fish and fish habitat. The ecological effects can range from direct fatality to organisms, alteration of the ecosystem structure through changes in the abundance, composition, and diversity of communities and habitats, and persistence and progressive accumulation in sediments or biological tissues (bioaccumulation, biomagnification). Deformities, alterations in growth, reproductive success, and competitive abilities can result.