The main goal of the project was to develop a GIS model that provides a analysis matrix that gives the risk exposure from natural hazards for the cultural resources within the Snoqualmie river floodplain.

1. Risk Analysis of Cultural Resources within
Snoqualmie Flood Plains
GIS Project Presentation
For King County GIS User Group
10.07.09
Presented By
Odra Cardenas
Shweta Bhatia Gupta
A r c h i t e c t u r e | Te c h n o l o g y | C u l t u r e

2. “GIS as a technology in the heart of
preservation planning, community building,
and effective decision making”

3. The Project
Relation between land and cultural resource
Cultural resources are the buildings, sites, areas, architecture, and properties that bear
evidence of human activity and have a scientific, historic, and/or cultural importance.
Cultural resources help define human history, remind us of our interdependence
with the land, and show how cultures change over time.
Hence cultural resource itself embodies the three important aspects of GIS
-Knowledge( Read information)
-Location
-Time
King County cultural resources
• The County’s cultural resources include around 2000 inventory, local, state and landmark
structures.
• The Snoqualmie valley, is home to historical railroad and timber Industries
• It is also home to the largest agricultural heritage within King County. The valley was
originally settled by members of the Snoqualmie tribe, and one can find displays of its native
American roots through relics like totem poles and archeological sites.

4. Snoqualmie Site
Farmlands are one of the most important component
of the county's historic and cultural resources.
In the last 16 years, the Snoqualmie valley
has experienced four of the worst floods on record,
including November 06's record-breaking deluge.
Within the Snoqualmie River basin floodplain
there are a total of 1,880 parcels.
This is approximately 40 percent of the total number
of parcels within King Countys floodplains (4,738).
There are structures at risk from flooding on 867 of
these parcels. The depth of flooding varies depending
on location.

5. The Goal
• Evaluating use of GIS as documentation tool in historic preservation
• Evaluating use of GIS as analytical and decision making tool
• Its resources and limitations

6. Methodology
Resource Research Process Management
Identification
Actual project plan
Data Data Gathering Database
Accumulation Defining dataset design
Work breakdown
structure
Creating feature set
Digitization
Task Division
Defining Of Matrix Reclassification Monitoring the
process
Status reports
Work quality
Model Building Time schedule
Analysis Reporting

7. The Process
• Stage 1:
– Data Collection
– Data cleanup
– Digitization
• Stage 2:
– Risk Matrix
– Database Design
– Reclassification for analysis
• Stage 3:
– Structural Analysis
– Site Level Analysis

8. Stage 1- Data Collection and Digitization
The two main sets of data were the geographical data and information about the structures on
the properties under consideration.
The former was collected from various GIS data repository and the later from local Historical
Archives.

9. Stage 2- The Matrix
The analysis was based on a risk matrix prepared to calculate percentage contribution each of
the factors considered. These contributions were then ranked ranging from 1 to 5 denoting the
lowest to highest risk levels to have uniformity across the analysis.

10. Stage 2- Risk Percentages
Analysis 1 40 % Status
Structural Risk
25 % Structural Condition
Foundation Type 40%
Cladding Type 20 %
20 % Structural/Material Roof Type 20 %
Roof Material 20 %
10 % Architectural Style
Change in Use 40%
Accessibility 30 %
5 % Site Condition Extant 30 %
The percentage Analysis 2 20 % Site Slope
contributors were decided Site Risk
on discussions with 20 % Site Soil
heritage preservation
program coordinators of 15 % Flood Way
the King County office and
research on the behavior of 45 % Flood Elevation
system types and materials

11. Stage 2-Integrated GIS Model
Feature
Historic Architecture
Point Polygon
HistoricProperty HistStructure
Polygon Polygon Polygon
HistPropretyID
Polygon
HistDistrictID HistoricDistrict HistMunicipality HistPropretyID
HistMunicipleID HistPropPolygon Polygon HistStructureID
Characteristics Summary Historic DistrictID Characteristics Summary
CharacteristicDetail HistPropretyID Location Info HistPropretyID CharacteristicDetail
Characteristics
Object Polygon
Historic Element
Archaeological District
HistElementID
ArchPropertyID
HistPropretyID Point
Location Info
Element Name[n]
Characteristics Archaeological Property
Element Type
Characteristics
ArchPropertyID
Feature SmithsodianID
Point ArchDistrictID
¼ Mile grid
HistElemPoint Property Name
ArchSite Grid Location Info
HistElementID Characteristics Summary
HasSites
HistPropretyID CharacteristicDetail
Location Info SiteDetails
Polygon
Feature Polygon
HistElemPolygon
ArchProperty Polygon
HistElementID
ArchPropertyID
HistPropretyID
Location Info Archaeological Site

12. Stage 2- Project Data
Flood Data Set Contour Data Admin Data
Flood Plain 5ft Contour Historic Site Point
Flood Way 2ft Contour
Contour _ Merge Historic Site Structure
Water Bodies Parcel KC Flood Plain Raster
Contour TIN
Zoning
Result Raster Set
Flood Plain uni
Soil 15
Slope
Parcel Flood
Parcel Soil
Parcel Slope
Flood pl reclass
Soil reclass
General Analysis
Slope reclass
Parcel Analysis Final Result
Modelwoflood Analysis
Structure Analysis Zone st –Par
Zonal St- Min
Zonal St- Mean
Models

13. Stage 3- Analysis at Structure Level
Formula: with a consideration 1 as low risk and 5 as highest risk rank
Total Structural Risk(%)= 20% X (structure Condition Rank)
+ 15% X (Structural material and construction type Rank)
+ 45% (Status and Arc Style Rank)+ 20% (Structure related Site Condition)

14. Stage 3- Analysis at Site Level
Formula: With a consideration 1 as low risk and 5 as highest risk rank
Total Site Risk(%)= 20% X (Slope Rank)+ 20% X (Soil type Rank)
+ 40% (100 yrs flood plain )+ 15% (Flood Elevation)

15. Stage 3- Analysis at Site Level(Model)

16. Results

17. Results
353
Snoqualmie Falls Lumber Mills
Year built: :1917
National Landmark registered
No of structures in site at risk : 17 out
of 22
Most endangered property according to
this study and at 88% of risk of flooding

18. Results
ITEM NAME NUMBER OF STR LOCATION RISK PERSENTAGE
1 Broadacre Farm 9 Carnation 70-78 %
2 Carnation Research Farm Historic District 16 Carnation 51-72 %
3 Curtis Link Farm 3 Carnation 48-53%
Fred Keller Barn
1
4 Carnation 36%
5 Hjertoos Farms 2 Carnation 66-68%
6 Charles Suvan & Louise 5 Duvall 29-47%
7 DeJong, Jerry Farm 12 Duvall 46-55%
8 Herman, Art and Letha Farm 5 Duvall 53-63%
9 John W. Platt Farm 4 Duvall 42-46%
10 Kosters Farm 9 Duvall 36-43%
11 Neilson Hay & Dairy Company 9 Duvall 39-53%
12 Old Rupard Place 9 Duvall 51-67%
13 Roetcisoender, James Farm 11 Duvall 47-59%
14 Roney Ranch 15 Duvall 56-63%
15 904 4 Duvall 74-81%
10
16 Sam and Marylin Rupard Farm/ Alder Grove Diary Duvall 43-55%
17 Stan Chapman Farm 8 Duvall 42-60%
18 Charles Jancke/Canine Country Club 9 Fall City 36-47%
19 Dale Brevick Residence 4 Fall City 33-37%
20 Donald Evans Farm 5 Fall City 47-48%
21 Fall City Hop Shed 1 Fall City 78%
22 Fred Keller Barn 9 Fall City 37-38%
23 Johnson House 2 Fall City 38-43%
24 Jubliee Farm 15 Fall City 37-52%
25 Mary Thompson Rental House 1 Fall City 57%
26 Residence 1 Fall City 55%
27 Stanley Little Residence 2 Fall City 52-55%
28 Thelma Hart House 1 Fall City 48%
15
29 Weyerhaeuser Company Snoqualmie Falls Plant Snoqualmie 69-82%
30 0739 42%
31 0716-1 42%
32 0717e 42%
33 0717d 42%
34 0717c 42%
35 0717a 42%
36 0902-3 42%
37 0902-4 42%
38 0902-2 42%
39 0902-5 43%
40 0902-1

19. Maps

20. Maps

21. Maps

22. Maps

23. Process- Flood information HEC RAS
TIN Flood elevation
Model developed by the US Corps of Engineers
Hydrologic Engineering Center (HEC)
River Analysis Systems (RAS)
Detailed survey information
Use of HEC RAS HEC1
Replicate information to verify data