Suspended Sediment and Turbidity Restrictions Associated With Instream Construction Activities in the United States: An Assessment of Biological Relevance

Sediment released during pipeline water crossings has the potential to negatively affect downstream aquatic resources. Regulation of pipeline water crossings has been directed through the application of allowable construction methods, timing constraints and numerical turbidity restrictions on construction permits. Past applications of turbidity restrictions are criticized for the following reasons: duration of exposure or sediment deposition effects are not considered; some applied restrictions are for the protection of primary productivity in lakes; and, defined mixing zones do not appear to incorporate expected levels of sediment generation, or sediment transport principles. Alternate approaches to defining permit restriction are proposed.