Tamarack stormwater runoff damage back before council–again

By Scott Hamilton

After nearly a decade and a half of little, the Sammamish City Council may finally be ready to address serious storm water drainage issues in the Tamarack subdivision on the city’s west side.

The issue is on the council’s agenda tomorrow night.

Tamarack has been subject to increasingly damaging storm water runoff as development uphill from the subdivision, which is sited on a downhill slope off Thompson Hill Road, flows through the neighborhood.

Erosion over the years

Some erosion of Tamarack properties was reported to the council on several occasions when homeowners appeared during public comment sessions. Resident Mary Wictor has been a regular during these sessions over the years, pointing out damage and hazards caused by the storm water drainage originating from homes and subdivisions approved by King County before city incorporation and by the city after incorporation.

Concern over storm water flowing unchecked into Lake Sammamish also has been voiced. Contaminants in the runoff can cause environmental damage, citizens claimed.

In 2016, the council punted stepping up to address the runoff. Debate swirled around using taxpayer dollars for privately-originating storm water runoff despite the city’s role (and the county’s before it) in approving development with what turned out to be inadequate runoff protection.

Minor city action

A contract was approved in 2016 for Downstream Analysis with modeling detention options plus Phase 1 public drainage easements. However, turnover of City staff halted this work before completion.

City action, as outlined in Tuesday’s agenda packet, included:

  • In 2013, as part of emergency repair actions to reduce the risk of additional landslides, City crews installed an overland tightline pipe on private property from 209th Ave NE to 208th Ave NE.
  • From 2010 to 2016, the City Council funded studies and preliminary engineering plans to evaluate drainage issues in the area. However, final engineering plans and construction were not funded due to the Council’s desire to complete the Zackuse Basin Plan which would give a holistic view of basin-wide problems and solutions.
  • In 2016, the City Council discussed ways in which partial funding could potentially be provided by the City with the private property owners paying most of the cost through a Local Improvement District (LID). This was deemed not feasible due to the unlikely approval by the property owners.
  • In 2017, the City’s insurer approved a monetary settlement with two private property owners in the Tamarack neighborhood for drainage problems related to the City’s emergency repairs in 2013.

Wictor virtually lobbied the council throughout 2015 for a solution. Then-Mayor Tom Vance, a self-avowed environmentalist, failed to lead the council to any action or solution that year.

4 thoughts on “Tamarack stormwater runoff damage back before council–again”

  1. This is an issue that the Council should have dealt with years ago. Unfortunately, some members, primarily Ramiro Valderrama, did not want to spend any money on it and effectively stymied any further Council action. In total frustration over the Council’s failure to step up to the issue I led the move to impose a local moratorium on any further construction in the Tamarack and Inglewood neighborhoods until the problem was resolved.

  2. I am sure one council member did not stop the process of fixing the problem. The council tends to use band-aids to repair problems that require true action. Parks are nice but we need to deal with real world issues that need fixing.

  3. The City of Sammamish sets and collects all stormwater fees and annual taxes to fund projects.
    Tamarack owners have paid over $600,000 in required stormwater fees and system development charges.
    For 2018 alone, Tamarack owners will also pay over $200,000 in taxes just to the City of Sammamish.
    However, since there is no “public” stormwater facility in Tamarack, the City carries no “burden.”

    What’s missing from the City’s action and information for tonight 7/2/19 are the following facts:
    Tamarack was 60% developed of 210 lots by the County thru the year 2000–without drainage issues!
    The City of Sammamish has permitted over 40 new homes on vacant lots 2000-2018.
    Tamarack is now 80% developed but there are still 40 vacant lots remaining; the City permits new homes.
    Numerous complaints have been made, multiple studies done and paid by the City with fixes identified.

    There should be a moratorium on building/expansions until drainage improvements are implemented.

    The Zackuse Basin Plan process did identify Tamarack tightline as a top project, but has pushed it aside.
    The City is reluctant to fund or act saying that this is a “private” area, but allowing growth via permits.

    The private roads in Tamarack are NOT the problem. Roadside ditches and culverts convey stormwater.
    However, excess runoff from development sends too much water, too fast, and for too long a duration.
    The ditches and culverts are overrun with fast, erosive flows, and the infiltrative soils are saturated.
    This causes flooding, which picks up pollutants with overflows heading to Zackuse Creek (key for salmon).

    Until 2017, the City also choose to use old 1998 King County drainage codes for any Lot less than 1-acre.
    This means the threshold for drainage review in portions of Tamarack was 5000SF instead of 2000SF.
    In late 2016, the City was forced to finally adopt new stormwater drainage codes or lose their NPDES permit.

    Also missing from the facts is that Tamarack has a Landslide Hazard area running North/South through it.
    The Growth Management Act (GMA) requires our City to identify/designate critical areas and protect them.
    Tamarack is the single location in the City without “drains to” areas above a mapped Landslide Hazard area.
    The City did correct this by changing their map to add the needed Landslide Hazard Drainage Area 1-1-17.

    The Growth Management Hearings Board views the GMA as having two (2) categories of critical areas:
    1) areas whose functions and values are protected by the beneficial services they provide (i.e., wetlands, aquifer recharge)
    2) areas for which protection is needed due to the threat these areas pose to persons and property (i.e., frequently flooded, geologically hazardous areas–landslide, erosion, steep slopes, and seismic.)

    Thus, the City has had their hand-in-the-mix every step of the way while Tamarack has grown by the size of 4 major subdivisions without formal central drainage pipe or area improvements (+40 vacant lots remain too.) Life and property are at risk with flooding regularly, icy roads, erosion of soils, and groundwater seepage appearing like springs coming out of the ground. Complaints have been made; the problems since 2007 are known and well-studied, and listed by the City as a Capital Improvement Project (CIP) since 2012.

    It is time that Tamarack gets the help it needs and deserves. The City must fully-funded and construct a drainage project to address safety risks in landslide hazards–as is stated in the 2015 Comprehensive Plan Goal EC.2: Protect people, property, and the environment on areas of natural hazards.

    Until then, don’t keep adding new growth in Critical Drainage Areas with problems/issues; don’t make the stormwater code and regulations weaker for historic areas with existing lots like Inglewood & Tamarack.

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