FEMA Region X – Risk MAP Discovery Interview
Lower Willamette - Tualatin Watersheds
City of Forest Grove, Oregon
September 14, 2012; 1:00pm Pacific Time
City of Forest Grove
John Holan – Planning Director
Derek Robbins – Engineer
Rob Foster – Public Works Director
Oregon DLCD
Steve Lucker – State Risk MAP Coordinator
FEMA Region X
David Ratté – Regional Engineer
Jen Monroe – Region X Risk Analyst
STARR (FEMA Contractor)
Becca Croft – Interviewer
Jason Sidorski – GIS Specialist
Gregg Pickett – Recorder
The following information was collected during the Interview. Unless otherwise noted, all comments are
from City of Forest Grove representatives.
I.
Contacts
 The contact list was reviewed and updated.
 All materials should be mailed to the City’s P.O. Box rather than their street address,
otherwise they are not likely receive it.
 GIS contact information to be emailed to STARR.
STARR (J. Sidorski) reviewed the GIS data that has been collected for the City of Forest Grove and
explained the types of additional data that could be beneficial to the project: parks, environmentally
sensitive areas, critical habitats, building footprints, parcels, topographic data (LiDAR, etc.).
II.
III.
Topography, LiDAR, and GIS
 The City has 2 GIS contacts, Leo Cortez and Dan Riordan.
 The City stressed that their urban growth boundary should be considered in this project.
Planning
 All City planning is done based on the urban growth boundary, not the city limits
boundary.
 The Gales Creek area was specifically noted as an area with potential urban growth
issues.
 The City of Cornelius and the City of Forest Grove are currently going through a Hazard
Mitigation Plan (HMP) update, with a draft version prepared in 2011. This is being done
as an addendum to the Washington County HMP. The City noted that this HMP update
Risk MAP Discovery Interview – Lower Willamette - Tualatin Watersheds
City of Forest Grove – September 14, 2012
IV.
V.
VI.
VII.
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may not take the City’s Comprehensive Plan into consideration. Assistance from Region
X to complete this work was requested by the City.
 Critical City structures in the event of an emergency include the local hospital, schools,
the fire station/emergency control center, and the water plant. The water storage
facilities that are located on David Hill are extremely critical to the City.
Earthquakes
 Earthquakes reaching 9.2 on the Richter scale are possible in the city of Forest Grove.
 There are two known faults in close proximity to Forest Grove; one near Hagg Lake and
the other along Gales Creek.
 There are a number of unreinforced masonry structures in the downtown area. There
are currently no plans in place to reinforce these structures.
Wildfires
 No regulations have been adopted, but the local fire department is a good source of
information for residents regarding wildfire hazards, proper buffers, etc…
 David Hill will continue to grow as a wildfire concern as development continues up the
hill. North Gales Creek Road, in the NW portion of the city, is currently the biggest
concern.
 Forest Grove owns a 5,000 acre forested watershed northwest of the city in the Upper
Gales Creek area. This area is closed to the public. There are significant timber assets
there, with the potential for wildfire.
Landslides
 David Hill has 15 to 20 residential units had to have special construction of their
foundations due to the slope of the topography and the soil. This area has shallow
groundwater and has slick soils, making it very susceptible to landslides.
 Soils on David Hill are so slick that when initial construction was underway for a
reservoir, portions of the project slid down the hill somewhat.
 150 residential units were placed in one area on/near David Hill, and the planning
process failed to take the special conditions into consideration during the preliminary
review process. Newer building regulations for the area are now much more strict.
 There is the potential of a landslide into nearby Hagg Lake, which could possibly put the
structural integrity of the dam at risk.
 The northwest portion of the city has the highest potential for growth, but also the
highest potential for landslides. Additional growth of 1400 to 1500 residences is
possible.
Severe Storms
 The local fire department study would be the best place to get data and policies
regarding severe storms.
 The city experiences occasional power outages and fallen trees, especially from
windstorms, but no long term problems typically occur.
 Forest Grove has its own light and power company, so outages are typically short.
Risk MAP Discovery Interview – Lower Willamette - Tualatin Watersheds
City of Forest Grove – September 14, 2012
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VIII.
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Forest Grove has not had the need to shelter people in the past.
The fire department’s management plan should be referred to for information regarding
outreach.
Flooding
 The Homestead (a senior community) was sandbagged in 1996 to keep the rising water
of the Tualatin River out. The whole area near the Homestead has relatively poor
stormwater drainage.
 Forest Grove’s largest private employer is located in the poor drainage area in the eastcentral portion of the city.
 The Dairy Creek Bridge, just west of Hillsboro on the Tualatin Valley Highway, flooded in
1996, and caused significant access problems for residents of the community, although
this bridge in not located within the city of Forest Grove. The approaches to the bridge
were overtopped by the flooded creek, causing the bridge to be temporarily closed.
This bridge, maintained by the Oregon Department of Transportation, has been slated
for a seismic retrofit, but no known changes to the bridge are known to alleviate
problems associated with flooding.
 Scoggins Dam which impounds Hagg Lake, was built in the mid-70’s to withstand a 7.5
earthquake. Some of the city’s water supply, as well as the water supply to some other
area communities, comes from this lake. Since recent studies have suggested that a 9.2
earthquake (Richter scale) is possible in the area, the dam is currently being studied for
the potential of a seismic retrofitting.
 Water from Hagg Lake is released from Scoggins Dam and eventually makes its way
down Scoggins Creek and eventually into the Tualatin River, where water intakes for a
75-million-gallon-a-day water treatment plant is located. This plant provides drinking
water for a number of cities in the area.
 Inundation maps have been developed by the Army Corps of Engineers to show what
would happen if Scoggins Dam were ever to fail. According to this study, a school and
The Homestead senior community would be inundated in the event of a dam failure.
 According to the City, the effective 1982 Flood Insurance Rate Maps (FIRMs) were based
on a faulty set of assumptions, and did not consider either a government levee or a a
private levee located in the city. The preliminary Washington County FIRMs still do not
address this issue, and according to the City are still wrong.
 The City was told by the Corps of Engineers that Gales Creek was not updated in the
current restudy because it was too complex. Gales Creek area would be a prime area
for any future detailed study, as would Carpenter Creek.
 Recent floods have been at least 8 feet above the elevations shown on the effective and
new preliminary FIRMs.
 No specific past mitigation projects with grant funding were known.
 The City does not allow development in the 1-percent-annual-chance floodplain.
Risk MAP Discovery Interview – Lower Willamette - Tualatin Watersheds
City of Forest Grove – September 14, 2012
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IX.
X.
XI.
XII.
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While no new structures have been built in the floodplain in recent years, a few older
structures are located within the 1-percent and 0.2-percent-annual chance floodplains.
Levees
 There is a government-maintained levee and a private levee located within the city of
Forest Grove.
 Since the private levee was not built to current guidelines and specifications, it is not
recognized as showing any flood protection on the effective FIRMs.
Environmentally Sensitive Areas
 A wetlands inventory was completed in 1995 and was list was recently updated, and
should be available from the Metro Regional Land Information System (Metro).
 Metro also has natural resource area data/maps.
 Washington County has vegetated corridor requirements that the City abides by,
including stream buffers of 25 to 50 feet.
Communications and Outreach
 Fire Department has likely done outreach, but specifics were not known at the time of
the interview.
 Special outreach projects might be necessary if flood mapping projects were to proceed.
 The Community Development Department would be the best place for residents to go
to obtain hazard information.
 STARR will give outreach materials to the City at the Discovery Meetings.
 Landslides on David Hill are the biggest risk, and City wants information about land use
regulations and the best ways to implement them.
 The City would like information regarding upcoming training opportunities.
Other
 City expects to attend the meeting in Beaverton at the Beaverton Library on September
24th.