Review Drainage Concerns at 17290 Germanium Street NW

Purpose:
The property owner at 17290 Germanium Street NW informed the City Council on November 13, 2018 that he was concerned the runoff from the Covenant Meadows residential development was flooding his property.  He also said the City Engineer had been unresponsive to his concerns and requests.
 
Staff will present information during the Public Works Committee meeting in response to the property owners concerns.  Staff invited the property owner to attend the meeting.
 
Background:
The property owner at 17290 Germanium Street NW built their home in 1992.  They built a garage in the southwest corner of the property in 1998, which was rebuilt in 2005 after the first garage burned down.  The garage was constructed in a low area of the lot, and was not elevated.  The garage door faced a private property which was used to access Germanium Street approximately 300-feet to the west.
 
In 2017, construction began on the Covenant Meadows residential development, which included construction of a new public street (172nd Lane NW) abutting the south property line of 17290 Germanium Street NW.  During construction of this development, the property owner contacted City Staff and the developer on numerous occasions to request modifications to the new driveway installed between his garage and 172nd Lane NW.  He also requested grading modifications to prevent drainage from entering his property from the north and west, noting he had issues with standing water on his property.
 
Before Covenant Meadows was developed (pre-development), 11.125 acres of land drained onto this property from the north and the west, contributing 3.1 cubic feet per second of runoff from a 100-year storm event.
 
After Covenant Meadows was developed (post-development), 1.306 acres of land drain onto this property from the north and the west, contributing 0.75 cubic feet per second of runoff from a 100-year storm event.  
 
Attached is a memo from the Engineering Department outlining pre and post-development drainage conditions.  Also attached are maps showing the pre and post-drainage areas that contribute runoff onto this property.
 
Regarding Staff’s responsiveness to this property owner during construction of Covenant Meadows, documentation is still being gathered and will be presented in detail during the meeting.
 
Senior Engineering Inspector Mike McDowall and Civil Engineer IV Leonard Linton will attend the meeting to provide additional insight, information and documentation as needed.  The developer also plans to attend to provide input as needed.

Approximately 25 minutes for presentation and discussion.

Staff believes this property benefited from the Covenant Meadows development in terms of reducing the amount of drainage entering the property.  As noted above the
 
Staff also believes we were very responsive to this resident during construction of the Covenant Meadows development.  Staff had many phone conversations with the property owner, and met with him on site numerous times.   Again, more information will be presented during the meeting.

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To be determined based on discussions.