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IntroductionBetween 1968 and 2010, Prince Edward Island lost approximately 5000 acres (or 25 square kilometers) of land due to coastal erosion. For landowners, the most effective way to protect their properties is through armouring their shorelines but many are unsure of the most efficient and cost effective way of doing so. This project will provide a way of assessing changes in coastal armouring over time, in order to help determine overall effectiveness.

Abstract

This study focuses on Augustine Cove, a coastal community on the South shore of PEI, and the effectiveness of its present shoreline armouring methods. Augustine Cove is an interesting site in that it has three distinct sections of shoreline for study - Living Shoreline (armouring through trees, plants and hay bales), Armour Rock and Unprotected (or natural).

Two different methods have been implemented - installing 8 pairs of erosion monitoring stakes, which create a linear path to the shore to measure erosion loss, and capturing visual mapping data through the use of a 3DR IRIS UAV (Unmanned Aerial Vehicle) – for measuring the coastline change at Augustine Cove. Stakes were installed and the initial flight took place in September of 2015.

Once the area is flown again during the Spring and Summer of 2016, the data from the IRIS will be processed with GIS software and we will then be able to examine changes to the shoreline by analyzing the imagery and calculating volumetric changes. This analysis will provide insight into the effectiveness of the armour rock and living shoreline armouring methods as well as how their erosion loss compares to the natural stretch of shoreline. Measurements from the more traditional erosion monitoring stakes, to be taken in Summer 2016, will provide additional information on the effectiveness of the current armouring methods.

Andy MacDonald (BSc), Andrew Clark (BSc) and Adam Fenech (PhD)University of Prince Edward Island (Climate Research Lab)

Comparing the Effectiveness of Armouring Techniques in Protecting the Eroding Coastlines Of Augustine Cove, Prince Edward Island, Canada

Living Shoreline Unprotected

- Layer of stone (limestone conglomerate) protects the shore from erosion due to wave action

- Very common protection method on Prince Edward Island

- Uses a variety of structural and organic materials (plants, hay bales, seaweed, branches etc.)

- Root systems provide stability

- No installed protection methods

- Fallen trees provide some natural protection

Armour Rock

Three Distinct Sections of Shoreline

Acquiring and Processing UAV Data

3DR IRIS UAV

- High resolution imagery

- Flight time of 10-15 minutes

Trimble GPS

- Used for georeferencing UAV data

- Accurate within 2 cm

Orthomosaic

- Once the imagery is processed, volumetric information can be

determined

Methods and Materials

UAV Flights

Between September 2015 and September 2016, five flights were carried out using a 3DR IRIS quadcopter UAV (Unmanned Aerial Vehicle). This UAV uses a Canon S110 12MP camera, producing high resolution imagery. Flights of the site took between 10 and 15 minutes, depending on wind conditions.

Erosion Monitoring Stakes

8 pairs of erosion monitoring stakes were installed throughout the study site, at 10m and 20m from the coastline. Measurements are made from the front pin to the edge of the cliff, using the back pin to create a line to the shore. This is a traditional erosion monitoring technique used on PEI.

Processing Data

Ground Control Point coordinates, collected by a Trimble RTK GPS unit, and photos are loaded into Pix4D, which is then able to provide a highly accurate Digital Surface Model, Orthomosaic and 3D model. These files can then be opened and analyzed in ArcGIS and Cloud Compare.

All of the flight data has been processed and analysis is underway with the goal of being finished by early 2017.

Importance

In analyzing the data obtained from both traditional (erosion monitoring stakes) and new (UAV data) methods, we will gain a greater understanding of the effectiveness of these shoreline armouring techniques and the possible advantages and disadvantages associated with each. This information would be valuable to landowners looking to minimize coastal erosion on their properties. Also, this project should shed a light on the numerous advantages of using UAV technology in coastal erosion assessment.