Policy

Title

Surfacing Groundwater Management within the City Right-of-Way Number

DWW-240 Rev. no.

0

Responsibility

SPU Drainage and Wastewater, SDOT Maintenance Operations Supersedes

N/A Pages

2

SPU Director's Approval SDOT Director's Approval

/s/ Ray Hoffman /s/ Scott Kubly Effective Date

July 1, 2016

1. PURPOSE

This policy establishes guidance for Seattle Public Utilities and Seattle Department of Transportation in addressing identified surfacing groundwater sites in the City right-of-way.

2. DEFINITIONS

surfacing groundwater. Subsurface water that seeps or percolates from the ground and manifests as pooled or flowing water on a pervious or impervious surface.

known site. A site recorded in the City's Geographic Information System typically after receiving an internal (City staff) or external (customer) report.

3. POLICY

A. The City of Seattle prioritizes known sites of surfacing groundwater for operational and capital improvements based on, but not limited to, the following criteria:

Major Criteria

Safety, as a function of the street classification, grade of the street, proximity to steep slopes, proximity to traffic-controlled intersections, and the size of the surfacing groundwater within the right-of-way.

Infrastructure impact, as to the degree of observed damage to public infrastructure as a result of the surfacing groundwater

Minor Criteria

Recurrence, as to how often the surfacing groundwater is present.

Source, as to the location where the surfacing groundwater is observed whether on private property or from City infrastructure within the right-of-way.

If the prioritization criteria need to change, staff from SPU Drainage and Wastewater Line of Business and SDOT Maintenance Operations must agree to the changes and the reprioritization of the known sites.

B. The City may fund fixing surfacing-groundwater problems that are caused by City infrastructure or adversely impact City infrastructure.

Source of Surfacing Groundwater Condition Possible City Response

City right-of-way From public drainage or other infrastructure Repair or replace drainage or other infrastructure

City right-of-way Natural source causing damage to City infrastructure Project to improve drainage and/or repair/replace damaged infrastructure

Private Property Direct discharge of surfacing groundwater from private infrastructure that is damaging public infrastructure Seattle Municipal Code enforcement to correct the problem

Private Property Natural source causing damage to City infrastructure within right-of-way Project to improve drainage and/or repair/replace damaged infrastructure in right-of-way

C. SPU and SDOT will periodically prioritize known sites and agree to develop budget requests for specific projects to address known sites which may include:

Major street or utility improvement projects that occur in areas of known sites.

Specific projects to repair and replace city infrastructure at known sites; these will include repairing and replacing the damaged infrastructure and managing the surfacing-groundwater impacts on the new infrastructure.

D. If funding requests are approved, a memorandum of agreement between SPU and SDOT for project funding (including cost sharing) and maintenance of new infrastructure will be developed.

E. The City does not fund corrective activities for problems on private property resulting from surfacing groundwater that occurs naturally on the property or from the actions of another private-property owner.