GEOB 270 Jan 2018Lab 3: Planning for flooding/Storm Surge

Spatial Analysis, Tables, Editing

Due: 2 week lab, due at the beginning of your lab time in 2 weeks. Any labs submitted after the start of your lab time, will be marked late. Lab out of 38

Introduction

In this lab, you will be working more with spatial and tabular datasets, both raster and vector. You will be reviewing (from lab 2) spatial and raster data, coordinates systems, projections, and then be introduced to a variety of basic GIS Analysis tools.You will be given a scenario for which you will perform GIS analyses. You will identify:

1. the scenario or problem to be solved; 2. the data you need; 3. the geographic analysis to be performed; the analytical operation or GIS tools you need to

access in ArcGIS4. the output maps of the results of the analysis 5. data integrity (accuracy, etc)

This lab and lab 4 and lab 5 will follow a similar 5 step process which will also be the process that you will come up with for your final projects.

1. Scenario (problem to be solved)

You are a GIS analyst with Metro Vancouver (all municipalities in the Vancouver Region).

Given the geological and climate change weather events that have transpired recently around the world, including recently in Tofino on Vancouver Island with the waves and flooding, your supervisor wants you to create a series of maps that highlight the areas in the Metro Vancouver that are at risk to flooding or a storm surge.

What are Storm Surges? - a rising of the sea as a result of atmospheric pressure changes and wind associated with a storm. From Wikipedia - storm surges: In the United States, one of the greatest recorded storm surges was generated by Hurricane Katrina in 2005, which produced a maximum storm surge of more than 25 ft (8 m) in southern Mississippi, with a storm surge height of 27.8 ft (8.5 m) in Pass Christian. Another record storm surge occurred in this same area from Hurricane Camille in 1969, with a storm tide of 24.6 ft (7.5 m), also at Pass Christian. A storm surge of 14 ft (4.2 m) occurred in New York City during Hurricane Sandy in October 2012.

Although the height, speed and inland reach of a storm surge and resultant flooding depend on many factors (winds, tides, inland waterways such are the Fraser River and False Creek, etc) we will simplify for this exercise that the immediate danger zone from a storm surge is mainly to the low elevation areas at, or below, 10 metres that lie up to 1 kilometre inland from the shoreline.

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You are to develop 5 maps and 1 table for your supervisor:1. and 2. overview map of map Metro Vancouver and of all areas of potential storm surge flooding – elevation from 0-10 meters, colour coded by elevation; second map done in layout view with legend and title. 3. map of potential flooding: refined analysis of potential storm surge by identifying areas of potential flooding by elevation within 1km of shoreline4. map of all roads affected by potential flooding, colour coded by type, with a table on the map summarized road type by total length5. False Creek tidal flats area detail map: finer resolution elevation information, map of schools, and new St. Paul’s hospital location that could be affected by potential flooding

2. The Data

Given the scenario and the expected deliverables (maps and tables above), in any GIS project, you should be creating a table of data that is necessary for this geographic analysis task.

Layer Name Description Raster/Vector Feature class Attributes sourcedem92g DEM, 25m

resolutionRaster tiff Value

(elevation)Open data Canada

fcdem1m DEM, 1m resolution, resamples from .5m

Raster tiff Value (elevation)

City of Vancouver

shoreline Outline of Metro Vancouver

vector line n/a Statistics Canada

roads Roads in Metro Vancouver

Vector line Road_type CanMap

education Schools in Metro Vancouver

Vector point Name, type CanMap

van_schools(download, not in Getdata)

Public schools in City of Vancouver

vector point City of Vancouver

Some of the data for this lab is open-data, in other words, free data available from the federal or municipal governments. There is one dataset we are using that is not open or public data, that UBC has a licence to use, and that is DMTI CanMap data.

Open Data Canada: http://open.canada.ca/data/en/dataset/7f245e4d-76c2-4caa-951a-45d1d2051333 - course resolution DEM, clipped to MetroVancouver;

Statistic Canada/Census Canada: - shoreline - geography file for Metro Vancouver Census Metropolotin Areas (CMA)

City of Vancouver: http://vancouver.ca/your-government/open-data-catalogue.aspx

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- fine resolution DEM of City from Lidar data (data was modified for your lab: DEM was clipped to False Creek area because size of DEM very large for whole class to be working with and storing on computers) - schools downloaded and renamed to van_schools

CanMAp data: in lab3 getdata – not open data https://www.dmtispatial.com/canmap/- Some of the data has been downloaded and bundled for you into a lab3 directory, some of the data you will access and download yourself.

Loading the Data

GetData: the file you load with GetData is zipped for compression as it contains 2 raster DEMs that are large files. You need to run extractall and set the path to C:\temp 

IMPORTANT: when you need to leave the lab, zip all the data in lab3 in C:\temp and copy the .zip file to H:

The dataset downloaded contains a geodatabase of shapefiles and 2 raster DEM or tiff files. Geodatabases provide a file management structure for the geo-spatial data in ArcGIS. With whatever GIS software you are using, it is always important for project management to carefully manage and store your data. Geodatabases offer structural, performance and data management advantages over a collection of shapefiles in a directory. In this lab, we have given you the data in a geodatabase. In the next lab, you will create a geodatabase.

Launch ArcCatalog as a standalone program and preview the contents of C:\temp\lab3\

QUESTION 1 (3) What is the coordinate system, projection, linear units, and datum for your geodatabase? What is the resolution of the dem92g (.tiff)? How accurate do you think this data is?

Close ArcCatalog.

Preparing a Geodatabase for Analysis

Launch ArcMap. In the Getting Started window select the Blank Map from My Templates and set your default geodatabase to C:\temp\lab3\analysis.gdb. Click on OK to begin. Save your map as c:\temp\lab3\mylab3.mxd.

Setting your default geodatabase to C:\temp\lab3\analysis.gdb will help you avoid losing your data. It will insure that the output of any analytical operation is stored in analysis.gdb as a feature class or a raster dataset, unless another location is chosen.

3. The Geographic Analysis: determine areas for possible storm surge flooding

a) Visually or cartographically classify raster DEM to show low elevation areasb) Create potential storm surge flood map: Low elevation within 1km shoreline:

i. Buffer shoreline by 1km: Perform buffer proximity analysis ii. reclassify raster layer to get only low elevation

iii. convert raster low elevation to vector

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iv. Combine the 1 km buffer and the lowlands (10m and under) with polygon overlay tool intersect to create area of potential flood from storm surge (low elevation, within 1km shore

v. Create map of potential flood c) Create map and summary table of roads that fall within potential flood

i. create table of total length of highways and expressways within potential flood ii. create map with major roads in potential flood highlighted, and summary table

d) False Creek Tidal Flats development: Detailed analysis of potential floodi. Zoom to detailed DEM of False Creek and create map of area symbolized

ii. Download schools from City of Vancouver open data site for display on mapiii. Digitize new layer of outline of new site for St. Paul’s Hospitaliv. Create map of detailed area

a) Visually or cartographically classify raster DEM (elevation) to display low elevation

We need to classify and symbolize the DEM to meaningful values and colours that represent low elevation flooding. Based upon historical data for storm surges, we will classify the elevation pixels (VALUE) into potential storm surge values that represent an elevation of 0-1 meter, 1-2 meters, 2-3 meters, 3-5 meters, 5-10meters to represent potential flooding, then 10-20 and anything over 20 as non-flooding risk areas. We will take the individual cell pixel values of elevation, and group them into these 8 categories for display purposes.

Bring up dem92g layer propertiesLayer > Properties > Symbology

Change default symbology from continuous colour ramp to classified. Under show, Click on Classified

Change default from 5 to 8 classes Click on ClassesChange classes to 8

Don’t worry about the colour rampClick on Classify…

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Under Break Values, change the default values to the following:0123510201,986

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Click OK Change colours individually of the classes.

Click on colour box beside 0Change colour to light grayOK

Change colours to shades of blue for 0-1, 1-2, 2-3, 3-5, 5-10Change colour to a green for 10-20 and then yellow for 20-1,986

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Click OK.Zoom and pan to get metro Vancouver in the centreSave your work as lab3_lowelevation.mxd

QUESTION 2 (3) Export your map to lab3_map1lowelevation.pdf submit

Create a map with a legend and a title:

Go to map or layout viewUnder View, click on Layout View

(if you right-click on the non-map/layout white space around the map, under page and print set up you can change orientation from portrait to landscape if you wish).

Insert a title and legend on your map Under Insert

Title – add a relevant title to your map

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Legend: ensure you only have a legend for dem92gUnder title for legend put in Elevation Meters Include all of the standard map elements (title, legend, scale bar, name + affiliation + date, north arrow, and data source, and coordinate system info).

Include all these map elements for any subsequent maps you create in this course.

QUESTION 3 (5) Export map to a pdf, call it lab3_map2lowelevleg.pdf

b) Create potential storm surge flood map: Low elevation within 1km shoreline: i. Buffer shoreline by 1km: Perform buffer proximity analysis

ii. reclassify raster layer to get only low elevation iii. convert raster low elevation to vectoriv. Combine the 1 km buffer and the lowlands (10m and under) with polygon overlay tool

intersect to create area of potential flood from storm surge (low elevation, within 1km shore v. Create map of potential flood

Visually, we have created a map of potential flooding. If we want to further refine our analysis to look at data of a certain elevation, within 1km of the shoreline, we need to do some geographic analysis with the data.

i. Buffer shoreline by 1km: Perform buffer proximity analysis

The first condition of our analysis is to find areas within 1km of the shoreline. To do this, we will use the Buffer tool.

Add the shoreline feature class to your empty map. Open the ArcToolbox window and expand the Analysis Tools by clicking on the ‘+’ sign next to

the toolbox. Expand the Proximity toolset and double-click on the Buffer tool. To create a 1km buffer around the shoreline, enter the following parameters and press OK:

o Input features: shoreline o Output feature class: C:\temp\lab3\analysis.gdb\shore1km o Linear unit: meters o Dissolve type: ALL

Every tool dialog box has a Help section that can be toggled on/off by using the Show Help >> or << Hide Help buttons in the bottom-right of the tool’s dialog window. As you enter the different parameters, the help content changes to explain what each parameter means.

o Click OK.

After a moment, the new shore1km layer is added to the Table of Contents (TOC).

NOTENotice that the buffer extends on both sides of the shoreline.

QUESTION 4 (1)

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What does 1 km represent; each side of the shoreline or the total width (use the measure tool)?

Notice as well that the buffer extends into the mountains, think about why this is, and whether it affect our analysis. This is an example of how you need to be aware of what is happening during GIS analysis and not just blindly click on buttons.

ii. reclassify raster layer to get only low elevation

The second condition in our analysis is that the land affected must be at or below 10 metres. dem92g - open its attribute table. Notice the number of pixels that exist at or below 10m

From Question 1What is the resolution of the DEM dem92g? (Hint: remember that units are important when expressing resolution)

QUESTION 5 (2)How many pixels have values of 10 metres or less in the Metro Vancouver DEM? How much area in km2 does that represent? (Hint: use the Statistics command)

For our analysis, we don’t really need the variety of elevation values. What we would like to do is to renumber all the low values as ‘1’ and the higher values to ‘NoData’. To do this simplification, we will use the Reclassify tool:

Make sure the Spatial Analyst extension is checked on under Customize > Extensions…

Bring up the ArcToolbox window and select Spatial Analyst Tools > Reclass > Reclassify In the Reclassify dialog window, enter the following parameters and press OK:

o Input raster: dem92g o Reclass field: VALUE o Click on the Classify button

o Under Method: Equal Interval (this will allow us to change the number of categories)

o Classes: 2o Under Break Values: type 10 for the first value and click OK

You should now have only 3 rows in the reclassification table. For the second row, change the New Value from ‘2’ to ‘NoData’

Set the output raster to C:\temp\lab3\analysis.gdb\lowelevation Click OK.

The lowlands raster layer is now added to the TOC. It contains values of ‘1’ for the areas under threat and nothing should be visible for the other areas.

iii. convert raster low elevation to vector

The areas we are searching for are those that are within a) the 1 km buffer and b) below 10 m in

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elevation. We need to combine these layers to isolate the areas common to both (i.e. the areas susceptible to the storm surge/flooding).

You can easily identify their intersection cartographically. To do this:

Turn off all layers except shore1km and lowelevation. Make sure the buffer is above the lowlands raster.

Open the properties for shore1km and under the Display tab enter a Transparency value of 30% and click OK.

The common areas between both layers should be easy to spot. However, in order to use this information in our analysis, we need to create a data layer containing these intersections. We first need to convert the lowelevation raster into vector:

In ArcToolbox, select Conversion Tools > From Raster > Raster to polygon. Enter the following parameters and click OK. The new vector layer is added to the TOC:

o Input raster: lowlands o Field: Value o Output polygon features: C:\temp\lab3\analysis.gdb\lowelevation_vector o Ensure that Simplify polygons is NOT checked

If you have not done so yet, this would be a good time to save your map document. Make sure to save it to C:\temp\lab3\ and NOT inside the analysis.gdb. The geodatabase should only contain actual data files.

iv. Combine the 1 km buffer and the lowelevation_vector (10m and under) with polygon overlay tool intersect to create area of potential flood from storm surge (low elevation, within 1km shore)

To create a vector layer that satisfies both conditions (area susceptible to a storm surge/flooding: within 1 km buffer, and <10 m elevation) we will combine them using the overlay tool called Intersect:

In ArcToolbox, select Analysis tools > Overlay > Intersect Enter the following parameters and click OK:

Features: lowelevation_vector, shore1km Output Feature Class: C:\temp\lab3\analysis.gdb\flooding Accept all other default values

After the new layer has been added to the TOC, turn off the lowelevation_vector & shore1km layer

save your work to lab3_flooding.mxd

v. Create map of potential flood

Go to map or layout viewUnder View, click on Layout View

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(if you right-click on the non-map/layout white space around the map, under page and print set up you can change orientation from portrait to landscape if you wish).

Insert a title and legend on your map Under Insert

Title – add a relevant title to your mapLegend: ensure you only have a legend for dem92g and flooding

QUESTION 6 (4) Export map to a pdf, call it lab3_map3flooding.pdf

c) Create map and summary table of roads that fall within potential floodI. create table of total length of highways and expressways within potential flood

II. create map with major roads in potential flood highlighted, and summary table

One of the advantages of GIS is that you can select features in one layer based on their location relative to features in a different layer. Since we have a polygon of flooding, and a layer of roads, we can use Select by Location to display all the roads that fall within the flooding areas.

Add Roads layer In the ArcMap menu bar, click on Selection > Select by Location Input the following parameters before pressing OK

o Selection method: select features from o Under Target layers put a check next to roadso Source layer: flooding o Spatial selection method for target layer feature(s): intersect the source layer feature

You will see all the blue roads that intersect the flooding areas are highlighted as selected. We will create an independent layer for these selected roads

Right-click on roads > Selection > create layer from selected features a new layers have been added to the TOC, roads selection you should only see roads within

the flood layerCreate a table of total length of roads in the potential flooded area, summarize by road type.

Open the attribute table for roads selection View the attributes Road_type indicated the code for highways etc At the end of this lab is a file which explains

the Road_type code. For the roads selection layer, symbolize expressways and highways (ROAD_TYPE 1 or 2) in a

thick black or red lineo Right click on roads selectiono Symbology

Click on categories, pick ROAD_TYPE as value, click on add all values Double click on 1 and 2 and change symbol to thicker black line or red line. For roads 3 4 5 leave as fine thin black line

Create a summary table of the total length for each road type that is affected by potential flooding:

o Right click on road type, summarize by shape_length, sum

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o Click yes to add table to TOCo Right click on table, Open table, you will see a summary by length.

QUESTION 7 (4) How many kilometers of highways and expressways (1 and 2 road_types) are affected by potential flooding?

Save your work to roadsflooding.mxd

In layout view, display roads in flood, with expressways and highways symbolized, and add the summary table to the layout

o open tableo top right icon is ‘table options’o click on ito select add table to layout option

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with a title.

QUESTION 8 (4)Export map to lab3_map4roadsflood.pdf

QUESTION 9 (2)How many schools fall within the potential flooding?(HINT: selection by location, education in flood; look at selected records in attribute table of education)

Save work to C and H drive.

d) False Creek Tidal Flats development: Detailed analysis of potential floodi. Zoom to detailed DEM of False Creek and create map of area symbolized

ii. Download schools from City of Vancouver open data site for display on mapiii. Digitize new layer of outline of new site for St. Paul’s Hospitaliv. Create map of detailed area with dem symbolized, schools and roads and outline of St

Paul’s hospital.

Now that we have done an overview of potential flood areas, we will load a more detailed DEM, colour code the elevation the same as our metro Vancouver DEM, zoom to False Creek area, add City of Vancouver schools and digitize the location of St. Pauls Hospital.

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i. Zoom to detailed DEM of False Creek and create map of area symbolizedIf you have not already done so, add the fcdem1m to your TOC.

Make the same classification and symbology as your dem92g; you can copy the symbology from dem92g to fcdem:

Go to the propreties > symbology tab Under show, click classified In this symbologoy window, yoju will see an icon of a file folder – and if you put your mouse on

it you will see imprt Click on the folder, and pick dem92g The symbology from dem92g should appear for the false creek dem

QUESTION 10 (2)What is the resolution of this dem? Or dem92g? Toggle back and forth between this fcdem and the 92g dem. What are 2 differences you see? How may these difference affect the analysis of potential areas of flooing?

ii. Download schools from City of Vancouver open data site for display on map

download Go to the City of Vancouver open data site, and to the list of files in the catalogue. http://data.vancouver.ca/datacatalogue/index.htm Download the schools shp or shape file to your lab3 directory. This is a zipped file. Unzip or extract all. You will have a folder called schools and files that

make up the shapefile inside that folder. Remember any time you copy a shape file, you copy the folder and all its contents.

Inport into geodatabase Open ArcCatalog Right click on analysis.gdb > import

Input features: schools Output location – ensure analysis.gdbOutput feature class: van_schools

Add van_schools to TOCPick a point symbol that is easy to see overtop of dem coloursLabel with name (right click on layer, label and school names will appear. (To change attribute to label, do that in properties under label tab)

QUESTION 11 (2)Toggle on and off the education layer. Are the points within the low elevation area the same? What are the differences?

iii. Digitize new layer of outline of new site for St. Paul’s Hospital

The City of Vancouver is currently undergoing a major new development on the False Creek Tidal Flats. Note the name of this development – it’s location is on the site of former tidal flats. Information on this

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development is here:http://vancouver.ca/files/cov/false-creek-flats-area-profile.pdfVancouver’s St. Paul’s Hospital has been designated to move to the west side of the False Creek Tidal Flats in Vancouver. See this link for the exact location. http://vancouver.ca/home-property-development/new-st-pauls.aspxThe initial plan for the development was released Wed. Jan 25, 2017.Given you have just completed an emergency preparedness map for the City in the event of a water surge due to storm, tusaumi, sea level rise, you will prepare a map visualizing the risk for the new hospital for flooding.

Creating a new feature classThe new data layers produced so far have been the result of analytical tools. It is sometimes necessary to create an empty canvas to locate new features.

In the ArcCatalog tab, right-click on analysis.gdb > New > Feature Class Name the new layer hospital Select Polygon features as they type of feature that will be drawn in the new layer and click

Next. The coordinate system should be the same as the other layers, so if the desired coordinate

system is not listed under favourites you can quickly import the reference information from another layer by using the Add Coordinate System button (see image below). You can import the information from any of the other layers in analysis.gdb. Click Next.

Accept the default values in the next two windows (XY Tolerance & Configuration). In the next window, add a field called Region of Text data type, and length of 25. Click Finish.

The new data layer is added to the TOC.

In this layer, you will digitize the polygon for the proposed hospital. Turn on the roads as they may help you locate the hospital. In order to modify, delete, or create features in a layer you need to launch the Editor Toolbar and start editing.

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In the TOC, right-click hospital > Edit features > Start Editing. The editor toolbar should appear.

Click on the Create Features button (right orange box in image above) if the Create Feature tabs is not already open.

The tab lists the layers that are available for editing. Select the hospital layer and the Construion Tools section of the tab will show the features that can be drawn in the selected layer. Keep in mind that these tools change according of the type of layers (point, line, and polygon).

Click on the Rectangle tool. Your pointer changes to a crosshair as you move around the map.

To start drawing, move to the location of the first polygon and click once to secure the first corner, move the pointer to the second corner and click again. This sets one side of the rectangle.

Now move your mouse to the where the 3rd

corner will be and double-click to finish. If you make a mistake, use the Edit Tool pointer

(the left orange box on the Editor Toolbar image above) to select the feature and use the Delete key to erase.

When you are in edit mode, you are can also update the attribute tables of the eligible layers. Open the hospital attribute table and, referencing the image above, update the name of the

hospital with its corresponding name. Notice that if you select the record on the table, the corresponding box will be highlighted.

Any updates you make to the tables or features are temporary. To make them permanent: From the Editor Toolbar > select Editor dropdown menu > Save edits When you are done making changes, Editor Toolbar > Stop editing.

It is extremely important that you stop an editing session before you save your map document. The two save procedures are independent of each other. Saving your map document will not automatically stop the editing session in progress and save the changes you have made.

An editing session is a very powerful tool. The tools available to you will depend on the type of layer you are working with.

iv. Create map of detailed area with dem symbolized, schools and roads and outline of St

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Paul’s hospital.

Create a map (layout) of the false creek area; include: Fcdem1m symbolized van_schools roads (all roads, clear selection from previous) hospital

o Legend of fcdem1m o Titleo Scale bar

Save your work as lab3_falsecreek.mxd

Question 12 (6)Save your map as lab3_map5falsecreek submit

4. Maps and Tables

Throughout our Geographic Analysis we created output maps (5) and one table which we included on one of the maps.

5. Data Integrity

In any geographic analysis scenario such as this, the final report will include maps, a listing of the data we used (under data) with sources and resolution, date etc, the GIS analysis methodology (step usually presented in a flow chart which you will learn for your final projects) and a section on Data Integrity – issues of data accuracy, data coverage, etc. For this lab, I had you think about data accuracy with the dem resolution, and with the schools layers.

Submit Answers/maps to Lab QuestionsSubmit answers to questions via the course web site: http://blogs.ubc.ca/giscience/labs/

PORTFOLIO POST (lab 3)

Create a post for your portfolio that includes a paragraph describing this storm surge scenario, and your completed 5 maps.

_____________________________________________________________________________________

Road_TYPE codes:

ROAD_TYPE Name Description

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1 Expressway Expressways and 400 series highways, e.g. Highway 401

2 Primary Highway Primary Highway, e.g. Highway 7, Highway 11

3 Secondary Highway Secondary Highways

4 Major Road Major road or Arterial road, e.g. Bayview Ave

5 Local Road Subdivision road in a city or gravel road in a rural area

6 Trail Trails

10 Main Main Railway and Transit Lines (includes segments of rail that are shared with transit)

11 Sidetrack Sidetrack of Main Railway Route

12 Abandoned Abandoned sections of Main Railway Route

13 Transit Transit lines that are not shared with Railway lines

20 Ferry Route Approximate travel route of Ferry

21 Ferry Ramp Ferry Ramp

22 Ice Road Approximate travel route of Ice Road

23 Ice Ramp Ice Ramp

24 Ferry Route/Ice Road Approximate travel route of Ferry/Ice Road

25 Ferry/Ice Ramp Ferry/Ice Ramp

http://vancouver.ca/files/cov/CFRA-Phase-1-Final_Report-Maps.pdf

http://vancouver.ca/files/cov/false-creek-flats-area-profile.pdfThe municipality is interested in the following information:

total area threatened, listed by land use type; length of the roads that might be affected, broken down by road type;

(highway, major road, local road, etc.); number of educational and health care facilities within the danger zone, if any;

locations to put up storm surge warning signage

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