Sediment Impacts from a Commercial Construction Site to Municipal Stormwater Retention Pond Infrastructure; A Narrative of Field Issues and Resolution

Dave Metallo, L.HG., CESCL, CCM

This session will be a narrative describing erosion and sedimentation impacts from a large (15-ac) construction site to an adjacent municipal stormwater retention pond over the course of the 2018-2019 wet season. How the SWPPP-driven inspection process was able to play a vital role in issue identification, management recommendation and response planning. We will revisit the root causes for impacts to a combined private & municipal stormwater drainage system. How the stormwater inspection team and CESCLs were able to be proactive early in the sedimentation identification process to aid in issue mitigation and to help guide the project stakeholders to a reasonable and practicable solution. We will have a look at the selected construction BMPs that were involved with this issue; those that failed and those that worked well. Finally, we will review the agreed design for sediment removal and have a look at the resultant field actions.

Learning Objectives

• Observation and identification of erosion and sedimentation issues through the inspection process
• Issue mitigation development / stakeholder consensus process
• Issue resolution, BMP selection, sediment removal design and field actions

Presented by Dave Metallo, L.HG., CESCL, CCM Terracon Consultants (Mountlake Terrace WA office)

Dave has 25+ years’ experience in environmental consulting, including: stormwater, active water treatment, construction support services, water quality monitoring, telemetry systems design and groundwater / soils & sediments projects