Dewatering: Deeper Big-Building Basements Near River Fill Sewers With More Groundwater

One of the odder new challenges we had to confont 2007 was the issue of dewatering.

Land located at lower elevations generally has groundwater closer to the surface. Construction sites that involve significant soil removal may expose groundwater, requiring dewatering efforts that discharge to the City's sewer system.

Sewer user fees are based on measured incoming water to the City treatment facility. Since groundwater is not being measured by a City utilities meter the City can require the installation of a private metering device to accurately calculate appropriate charges.

This past year Sam ordered a complete evaluation of all construction sites to ensure that all commercial customers were paying appropriate and accurate sewer user charges relating to ground water discharge.

In July 2006, the City of Portland established a system to equitably and consistently recover the expense of conveying and treating groundwater discharges to the City's sewer system.

The Bureau of Environmental Services administers the Sub-meter program which is responsible for ensuring that these fees and charges are accurately applied to commercial/industrial customers that discharge groundwater into the sewer system.

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