Risk Analysis of Cultural Resources within Snoqualmie Flood Plains

GIS Project Presentation

For King County GIS User Group

10.07.09

A r c h i t e c t u r e | T e c h n o l o g y | C u l t u r e

Presented By

Odra Cardenas

Shweta Bhatia Gupta

“GIS as a technology in the heart of preservation planning, community building,

and effective decision making”

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.

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.

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

Methodology

Resource

Identification

Data

Accumulation

Research

Data Gathering

Defining dataset

Defining Of Matrix

Database

design

Creating feature set

Digitization

Reclassification

Analysis

Process

Model Building

Actual project plan

Work breakdown

structure

Task Division

Monitoring the

processStatus reports

Work quality

Time schedule

Reporting

Management

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

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.

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.

Stage 2- Risk Percentages

40 % Status

25 % Structural Condition

20 % Structural/Material

10 % Architectural Style

5 % Site Condition Stru

ctu

ral R

isk

Foundation Type 40%Cladding Type 20 %Roof Type 20 %Roof Material 20 %

Change in Use 40%Accessibility 30 %Extant 30 %

20 % Site Slope

20 % Site Soil

15 % Flood Way

Site

Ris

k

45 % Flood Elevation

Analysis 1

Analysis 2The percentage

contributors were decided

on discussions with

heritage preservation

program coordinators of

the King County office and

research on the behavior of

system types and materials

Stage 2-Integrated GIS Model

Historic DistrictID

Location Info

Characteristics HistPropretyID

HistoricDistrict

PolygonHistPropretyID

HistDistrictID

HistMunicipleID

Characteristics Summary

CharacteristicDetail

HistoricProperty

Point

HistPropPolygon

HistPropretyID

HistMunicipality

Polygon

PolygonHistPropretyID

HistStructureID

Characteristics Summary

CharacteristicDetail

HistStructure

PolygonPolygon

Polygon

HistElementID

HistPropretyID

Element Name[n]

Element Type

Characteristics

Historic Element

HistElementID

HistPropretyID

Location Info

HistElemPoint

Point

HistElementID

HistPropretyID

Location Info

HistElemPolygon

Polygon

Object

Feature

HasSites

ArchSite Grid

¼ Mile grid

Historic Architecture

ArchPropertyID

Location Info

Characteristics

Archaeological District

Polygon

ArchPropertyID

ArchProperty Polygon

Polygon

ArchPropertyID

SmithsodianID

ArchDistrictID

Property Name

Location Info

Characteristics Summary

CharacteristicDetail

SiteDetails

Archaeological Property

Point

Feature

Feature

Archaeological Site

Flood Data Set

Flood Plain

Flood Way

Water Bodies

Contour Data

5ft Contour

2ft Contour

Contour TIN

Contour _ Merge

Historic Site Point

Historic Site Structure

Parcel KC

Zoning

Admin Data

Models

Flood Plain Raster

General Analysis

Parcel Analysis

Modelwoflood Analysis

Structure Analysis

Result Raster Set

Parcel Flood

Parcel Soil

Parcel Slope

Flood Plain uni

Soil 15

Slope

Flood pl reclass

Soil reclass

Slope reclass

Final Result

Zone st –Par

Zonal St- Min

Zonal St- Mean

Stage 2- Project Data

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)

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)

Stage 3- Analysis at Site Level

Stage 3- Analysis at Site Level(Model)

Results

353

Results

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

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%

4

Fred Keller Barn

1

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%

16 Sam and Marylin Rupard Farm/ Alder Grove Diary10

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%

29 Weyerhaeuser Company Snoqualmie Falls Plant15

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

Results

Maps

Maps

Maps

Maps

Model developed by the US Corps of EngineersHydrologic Engineering Center (HEC)River Analysis Systems (RAS)

TIN Flood elevation

Detailed survey information

Use of HEC RASReplicate information to verify data

HEC1

Process- Flood information HEC RAS