COASTAL MONITORING IN NEWFOUNDLAND AND LABRADOR

Peter DesveauxMUN Geography Department

ABSTRACT

Coastal areas in Newfoundland and Labrador are important because of their relatively

high populations and significance in commerce. Coastline change poses a threat which must be

examined and studied in order to understand its magnitude. The Newfoundland and Labrador

Coastal Monitoring database, consisting of compiled data as well as newly acquired data, was

reviewed and the layers and fields populating it were optimized for use in the Digital Shoreline

Analysis System (DSAS).

The Pointe Verde area, on the Avalon Peninsula in Newfoundland, was assessed using

DSAS. Annual retreat rates range from 0.54 m/year to 0.15 m/year. When calculated across the

study period from 1993 to 2013, it indicates erosion of up to 12 m.

The best method of displaying the Point Verde data in the NL GeoScience Atlas, is to

display the shoreline study area as a line which will be linked to an airphoto that displays the

individual shorelines at a much higher resolution. The line will also be linked to the DSAS

shoreline changes statistics, such as shoreline change envelope, net shoreline movement and end

point rate.

Coastal monitoring in Newfoundland and Labrador has become a very important issue in

recent years. Coastal regions are dynamic environments that must be monitored in order to be

fully understood. The majority of people in the province live in coastal areas, and processes such

as erosion, flooding and mass movement affect these areas, which makes it imperative that these

coastal areas are monitored. Extensive work has been done on this subject internationally as well

as locally. The work of M. Irvine, M. Batterson, and D. Liverman of the Newfoundland and

Labrador (NL) Department of Natural Resources will be discussed here. This report describes the

coastal monitoring programs in NL, the organization of the databases, and explores how the

resulting information can be displayed on the NL GeoScience Atlas.

Sea-level change due to climate change is an issue that is resulting in the need for

monitoring in coastal areas around Newfoundland and Labrador. Projected impacts of climate

change will increase the risk of coastal hazards to different degrees around the province. For

example, changes in temperature and precipitation could result in heavier snow storms and rain

events (Finnis, 2013). Some areas around the province are projected to experience a significant

change in sea-level over the next century. The west coast of Newfoundland and the Avalon

Peninsula, the most populated areas of the island, could expect a sea-level increase of 80-100+

cm by 2099 (Figure 1; Batterson & Liverman, 2010).

Figure 1. Projections of potential relative sea-level rise in Newfoundland and Labrador by 2099 (Batterson & Liverman, 2010).

A coastal monitoring program was initiated in 2011 by the Geological Survey of

Newfoundland and Labrador (GSNL) in order to collect and interpret data to quantify rates of

coastal migration (both erosion and accretion), understand beach dynamics and assess areas at

risk to coastal flooding (Irvine, 2012). This program builds upon previous research by Forbes of

the Geological Survey of Canada (GSC) in 1981, and by Liverman, Forbes and Boger of the

GSNL in 1994. There were also photos taken around the province in the 1950’s - these can be

used to compare the past coastline with recent site photos and airphotos.

The main aspect of the present program, consisting of over 100 coastal sites in

Newfoundland and Labrador, is to examine the areas quantitatively to observe the shoreline

changes over many years. For this program, the cliff line was used as an alternate to measure

how much the shoreline changed. Shoreline is a generic term used to denote where erosion or

accretion is being measured. One of the challenges in this project is the organization of an

efficient database to be useful for a variety of purposes including having the results available for

public display and download on the Newfoundland and Labrador GeoScience Atlas

(http://gis.geosurv.gov.nl.ca).

DIGITAL SHORELINE ANALYSIS SYSTEM

A useful analysis tool in displaying and monitoring coastline change is the Digital

Shoreline Analysis System (DSAS). This is a freely available software system that works within

the Environmental Systems Research Institute (ESRI) ArcGIS software (Thieler et al., 2009) and

provides statistics for monitoring coastal change. However, the underlying database must be

organized using DSAS specifications in order to obtain optimal results.

Thieler et al. (2009) describe how coastline data must be organized in order to be able to

calculate coastline change statistics. Both baseline and shoreline data are required to calculate

coastline change. The baseline (Figure 2) is constructed by the user and serves as the starting

point for all transects cast by the DSAS application. The shoreline positions (Figure 2) represent

a specific position in time and can reference several features such as the cliff-top line, vegetation

line, the high water line, or the low water line (Thieler et al., 2009). Transects (Figure 2) are

placed by the DSAS program, perpendicular to the baseline at user defined intervals, crossing the

shorelines. The intersection that occurs between transects and the shorelines permit the

computation of statistics concerning coastline change.

Figure 2. An example of baseline, shoreline and transect lines. The distance from the baseline to each measurement point is used in conjunction with the corresponding shoreline date to compute the change-rate statistics (Thieler et al., 2009).

There are several statistics calculated in DSAS that show how a shoreline has changed

over time. These include shoreline change envelope (SCE), net shoreline movement (NSM), and

end point rate (EPR).

Shoreline change envelope is the distance between the shoreline farthest from and closest

to the baseline at each transect (Figure 3). This represents the total change in shoreline

movement for all available shoreline positions and is not related to their dates (Thieler et al.,

2009).

Figure 3. An example of shoreline change envelope. Here it is 86.59 metres from the 2005 to 1963 shorelines (Thieler et al., 2009).

Net shoreline movement reports the distance between the oldest and youngest shorelines

for each transect (Figure 4). This represents the total distance between the oldest and youngest

shorelines (Thieler et al., 2009).

Figure 4. An example of net shoreline movement. Here it is 76.03 metres from the oldest shoreline (1936) to the most recent (2005) (Thieler et al., 2009).

End point rate is calculated by dividing the distance of shoreline movement by the time

elapsed between the oldest and the most recent shoreline (Figure 5). EPR is advantageous because it

is easy to compute and only requires two shoreline dates. However changes in sign (for example,

accretion to erosion), magnitude, or cyclical trends may be missed (Crowell et al., 1997; Dolan et al.,

1991).

Figure 5. An example of end point rate. Here it is 1.09 metres per year. The distance from the oldest shoreline (1936) and the most recent (2005) is divided by the time elapsed between the two (69.82 years). (Thieler et al., 2009).

In order to utilize DSAS, an ArcGIS personal geodatabase must be implemented. This

will serve to store all data that is used and produced by DSAS. Another requirement is that all

data must be in meter units in a projected coordinate system such as UTM, NAD 1983.

The shoreline data is the key database when examining coastline change. All shoreline

data must be appended to a single feature class in the geodatabase. Table 1 lists the fields

required for the shoreline feature class. Each shoreline must have a date attached to it, indicating

when it was recorded, and an uncertainty value, indicating the accuracy. This will be used in the

statistical calculations.

Table 1. Attribute fields for shoreline data (Thieler et al., 2009).Field Name Data Type Input Type Input

OptionComments

OBJECTID Object ID Auto-generated

Required Establishes a unique ID for each row in the attribute table.

SHAPE Geometry Auto-generated

Required Provides a definition of the feature type (point, line or

polygon).

SHAPE_Length Double Auto-generated

Required Provides the length of the feature.

DATE_ Text User-created

Required Date of shoreline data. Can be a length of 10

(mm/dd/yyyy) or 22 (mm/dd/yyyy hh:mm:ss).

UNCERT_m Any numeric

field

User-created

Required Accounts for positional (wind, waves) and

measurement uncertainties (digitization, GPS errors). Different uncertainties can

be provided for each shoreline segment.

Baselines must also be in a single feature class in the geodatabase, and can be a single

line or a collection of segments (Figure 6). Similar to shorelines, there are required attribute

fields in the baseline feature class (Table 2).

Figure 6. The three baseline segments are an example of how to correctly place a combination of onshore and offshore baselines. Each baseline is placed so that all shoreline data is off to one side (Thieler et al., 2009).

Table 2. Attribute fields for the baseline feature class (Thieler et al., 2009)Field Name Data

TypeInput Type Input

OptionComments

OBJECTID Object ID Auto-generated

Required Establishes a unique ID for each row in the

attribute table.SHAPE Geometry Auto-

generatedRequired Provides a definition of

the feature type (point, line or polygon).

SHAPE_Length Double Auto-generated

Required Provides the length of the feature.

ID Long Integer

User-created Required Used to determine the ordering sequence of transects when the

baseline feature class contains multiple

segments. You must designate a unique ID

value for each segment of the baseline in the

attribute table. Group Long

IntegerUser-created Required Used to aggregate

transects on the basis of physical variations

alongshore. Facilitates later sorting and analysis

of the data.OFFshore Short

IntegerUser-created Optional This field is needed if

onshore and offshore baselines are used. A

value of 0 indicates the baseline is onshore, while a value of one indicates

the baseline isoffshore.

CastDir Short Integer

User-created Optional This field is needed with OFFshore. A value of 0 results in the transects being cast to the left of

the baseline, while a value of 1 results in the

transects being cast to the right of the baseline.

FROM RTK DATA TO DISPLAY IN THE GEOSCIENCE ATLAS

The model shown here illustrates the method used to go from initial data (RTK) to

accomplishing the final goal (displaying data on the GeoScience Atlas). There are several steps

needed to accomplish this, and multiple computer programs are needed, mainly Microsoft Word

and ArcGIS. The model uses shapes similar to the model builder in ArcMap. Yellow squares

represent tools, green circles represent output, blue circles represent input, and brown octagons

represent loops. There are several processes that combine to form the correct feature classes and

database required in DSAS.

Create a personal geodatabase

RTK point shoreline shapefile

Convert point to line

RTK point shoreline shapefile (see Table 3)

Merge into one feature class

Repeat for each shapefile

Export data from RTK and into Microsoft

Excel

RTK Shoreline data in Excel

RTK Line feature class for each shoreline

Create point shapefile for each RTK shoreline

Combined RTK shoreline feature class (see Table 4)

Combined RTK shoreline feature class

Create shoreline feature class with fields needed for

DSAS

Append combined RTK shorelines into DSAS feature

class

DSAS Shoreline feature class (empty). (See Table 1)

Add date and uncertainty

fields in DSAS feature class

DSAS Shoreline feature class with all attribute data (See Table 5)

Create baseline feature class

Baseline feature class (See Table 2) Add necessary

attribute data

Baseline feature class with all attribute data (see Table 6)

Run DSAS tool a) Cast transects

b) Compute desired statistics

Transects and coastline change statistics

DSAS Shoreline feature class with all attribute data

Baseline feature class with all attribute data

Convert to Images

Prep database for Atlas and update linked

fields

Images of shoreline change envelope, net shoreline movement and end point rate

Atlas database with feature classes and links

Open registered airphotos and overlay

DSAS shorelines (Figure 9) and convert

to images

Images of airphotos with shorelines

DSAS Shoreline feature class with all attribute data

Table 3. Example of RTK point shoreline shapefile fields.

Table 4. Fields when RTK shorelines combined into one line feature.

Table 5. Shoreline data to be used in DSAS. Note uncertainty is not used. Uncertainty data is still being prepared, therefore it was not available here.

OBJECTID Shape Date_ Uncertainty Length_m1 Polyline 10/16/1993 <Null> 656.622 Polyline 11/07/2000 <Null> 731.023 Polyline 08/09/2012 <Null> 796.564 Polyline 06/08/2013 <Null> 752.57

Table 6. Baseline data to be used in DSAS.OBJECTID Shape ID Group_ OFFshore CastDir Shape_Length

1 Polyline 1 1 0 0 709.40

POINT VERDE COASTAL CHANGE

The coast of Point Verde, NL was studied by the Geological Survey of Canada in 1993

and 2000 and by M. Irvine (2013) in 2012 and 2013. The shoreline locations were collected and

used to calculate statistics concerning shoreline change in the area. A baseline was created and

transects were cast perpendicular from the baseline across the shorelines, allowing for the rate of

change of shoreline erosion to be calculated at the junction of transect and shoreline. Figure 7

shows the shoreline change envelope values at each transect/shoreline intersection along the

coast of Point Verde. A shoreline change envelope represents the total change in shoreline

movement for all available shoreline positions and is not related to their dates (Thieler et al., 2009).

Figure 7. Shoreline change envelope values for transects in Point Verde, NL.

Figure 7 shows that the majority of shoreline change envelope values in Point Verde are

over 6 m, indicating that most areas along this coast have experienced coastal erosion of at least

6 m during the 22 year study period.

Figure 8 displays the end point rates at each transect. This is a statistic calculated by

dividing the distance of shoreline movement by the time elapsed between the oldest and the most

recent shoreline (Thieler et al., 2009). It indicates how much, on average, the shorelines

intersecting each transect are retreating each year. The display is effective because changes can

be easily observed through the color and line thickness. Annual retreat ranges from 0.54 m/year

to 0.15 m/year. When calculated across the study period from 1993 to 2013, it indicates erosion

of up to 12 m in some areas.

Figure 8. End point rates of shorelines in Point Verde, NL

GEOSCIENCE ATLAS REVIEW

The NL GeoScience Atlas is an online resource to explore the geology and geography of

Newfoundland and Labrador. The purpose is to provide a portal to view, query and download

geoscience data for Newfoundland and Labrador (Honarvar, 2013).

There are many features that can be toggled on or off in the GeoScience Atlas. Layers

that can be displayed include geochemistry sites, mineral lands, and petroleum resources.

Basemap themes such as bedrock geology, surficial geology, and geophysics can also be

selected. There are several tools that can be utilized when using the Atlas. The user can zoom

and pan around the map, measure and select features, and perform queries and identify features.

Another component of the GeoScience Atlas is viewing information at different scales. Zooming

in on various layers, such as map labels or map staked claims, provides additional labels at larger

scales. Other information, such as bedrock and surficial geology, are available as regional and

detailed layers.

A new group in the new Geoscience Atlas, to be available in April 2014, is the

Geohazards group. This is where the coastal monitoring information will eventually be placed.

Incorporating it in the GeoScience Atlas will provide the public with easy access to the

information. Areas examined for shoreline change will be displayed and statistics will be linked

in order to provide the user with an informative overview of the coastal change occurring in

Newfoundland and Labrador.

DISPLAY OF COASTAL MONITORING DATA

One of the goals of this report is to determine how to display coastal monitoring

information on the GeoScience Atlas. The main data consists of baselines, shorelines and

transects used to calculate various coastline change statistics.Many shorelines around the

province erode at rates of 0.20-0.50 metres each year, so over 30 or 40 years the change in

shoreline position could be 6-20 m, requiring a scale of at least 1:10,000 to resolve the lines for

low erosion areas. The largest zoom scale of the Geoscience Atlas is 1:18,000 which will not be

good enough to resolve some lines (Figure 10). However when these lines are selected in the

Atlas, the associated attribute table (Table 7) will be displayed with a link to an airphoto, through

a Site_Photo field, that displays the shorelines at a much higher resolution (Figure 10,

approximately 1:2500). Similarly, the shoreline change statistics, such as shoreline change

envelope, net shoreline movement, and end point rate, can be converted to jpg images and linked

to a ChangeStat field, enabling the user to view relevant statistics showing erosion or accretion.

Figure 9. Erosion is depicted as three cliff-top positions measured over a 21 year span, displayed on an orthorectified air photo (Irvine, 2013).

Figure 10. Example of eroded shorelines to be displayed on the GeoScience Atlas. In this case the red line represents the cliff top.

Table 7. Attributes associated with shorelines in the GeoScience Atlas.Field Data Type Description

FID ObjectID Automatically generated, establishes a unique ID for each row in the attribute table.

Shape Geometry Automatically generated, provides a definition of the feature type (point, line or polygon).

Shape_Len Double Automatically generated, provides the length of the feature.

Date_ Text Date of shoreline data. Can be a length of 10 (mm/dd/yyyy) or 22 (mm/dd/yyyy hh:mm:ss).

Uncert_m Double Accounts for positional (wind, waves) and measurement uncertainties (digitization, GPS errors). Different measurement uncertainties can be provided for each shoreline segment.

Site_Photo Text A link to an air photo of the specified site with measured shorelines.

ChangeStat Text A link to DSAS change stats chart (as a jpg)

CONCLUSION

The NL GeoScience Atlas will be an effective tool in viewing shoreline change. The

statistics calculated, such as shoreline change envelope, net shoreline movement, and end point

rate, will provide the user with a comprehensive view of shoreline change in the area. Air photos,

displaying the cliff-top location over various years, will be another resource that allows the user

to further understand how shorelines are changing. The example of Point Verde shows coastline

change is a prominent issue in Newfoundland and Labrador and warrants additional study.

This research has helped optimize the coastal monitoring database which allows for

future work to be completed using the same template. Resources such as DSAS and the

GeoScience Atlas will allow for further study and display of the results, permitting a greater

understanding of this issue.

ACKNOWLEDGEMENTS

Pauline Honarvar is thanked for her assistance in completing this project. Her help in

setting up the framework of the project and reviewing it is very much appreciated. Melanie

Irvine is thanked for sharing her data and expertise on the subject. The paper was improved by

her reviews as well. The Geological Survey of Newfoundland and Labrador provided a work

environment suitable to complete this project and is thanked as well.

REFERENCES

Batterson, M. and Liverman, D.2010: Past and Future Sea-Level Change in Newfoundland and Labrador: Guidelines for Policy and Planning. In Current Research. Newfoundland and Labrador Department of Natural Resources, Geological Survey, Report 10-1, pages 129-141.

Crowell, M., Douglas, B.C., and Leatherman, S.P.1997: On forecasting future U.S. shoreline positions— a test of algorithms: Journal of Coastal Research, v. 13, n. 4, pages 1245-1255.

Department of Natural Resources, Government of Newfoundland and Labrador.NL GeoScience Atlas. http://gis.geosurv.gov.nl.ca/.

Dolan, R., Fenster, M.S., and Holme, S.J.1991: Temporal analysis of shoreline recession and accretion: Journal of Coastal Research, v. 7, pages 723-744.

Finnis, J.2013: Projected Impacts of Climate Change for the Province of Newfoundland &Labrador. Department of Geography, Memorial University of Newfoundland. The Officeof Climate Change, Energy Efficiency & Emissions Trading, pages 1-134.

Honarvar, P., Nolan, L.W., Crisby-Whittle, L., Morgan, K.2013: The Geoscience Atlas. In Current Research. Newfoundland and Labrador Department of Natural Resources Geological Survey, Report 13-1, pages 1-3.

Irvine, M.2013: Coastal Monitoring in Newfoundland and Labrador: 2012 Update. In Current Research. Newfoundland and Labrador Department of Natural ResourcesGeological Survey, Report 13-1, pages 43-54.

Irvine, M.L.2012: Coastal Monitoring in Newfoundland and Labrador. In Current Research. Newfoundland and Labrador Department of Natural Resources,Geological Survey, Report 12-1, pages 191-197.

Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A.2009: Digital Shoreline Analysis System (DSAS) version 4.0 — An ArcGIS extension for calculating shoreline change. U.S. Geological Survey Open-File Report 2008, pages 1-79.