|Overview||Research Projects||Esri Story Map|
Grand Lake Meadows is the largest freshwater marsh/wetland in the province of New Brunswick. The region consists primarily of a broad flat floodplain and wetland meadow, with elevations ranging from sea level up to ~16 meters. Grand Lake Meadows is classified as a Class II Protected Natural Area by the government of New Brunswick. This classification protects the area from development and allows ‘low impact’ recreational activities. Grand Lake Meadows is known for its diverse ecology and its abundant wildlife. This diversity is due to three factors:
Grand Lake is the largest open body of water in New Brunswick being a total of 20 miles long and 7 miles wide [Nason, R. 2013]. This large body of water acts as a heat sink: moderating local temperatures, creating the warmest climate in the province, and extending the growing season [D’Arcy, M, 2008].It is considered a floodplain wetland because on any given year approximately 85% of the area is inundated by seasonal floodwaters [Dickinson, P.J, 2008]. In addition to the seasonal flooding, tides displace water and may cause flooding in Grand Lake Meadows.
Flood waters from both the Saint John River and Grand Lake have the potential to make a dramatic impact on the meadows ecosystem. Although freshet is seasonal, with peaks each spring, it may occur at an time of the year. It is most often caused by heavy rainfall, rapid melting of a thick snow pack, ice jams or failure of a natural or artificial dam. Major flooding was recorded in the Grand Lake Meadows recently (2008) and several times over the last decades (2005, 1993, 1979 and 1973).
The overflow of water that occurs during a flood can have consequences, both positive and negative, for the physical environment as well as the flora and fauna of the Meadows ecosystem. It therefore becomes a necessity to monitor water levels and map the dry and wet areas in the Meadows on a regular temporal basis. From these records, flood prone areas in the Meadows will be apparent. Additionally, analysis of these spatial-temporal records will lead to a better understanding of the flood waters impact.
The overall objective, is to create a repository of flood related data and enhanced map visualizations. Advanced tools will be developed to assist the online analytical processing of the content, while both source data and results of the analysis will become accessible through advanced geospatial web services.
This project is divided into two components: (a) data collection and (b) preparation and visualization.
Data collection and preparation is gathered from a variety of sources. Much of this data was acquired from government and public records. Many of these records had previously been digitized and available through electronic means, however the bulk of this data is not. An extensive search of four different library systems in the Fredericton area (UNB Libraries, Provincial Libraries, Provincial Archives, and the Legislative Library). These resources provided valuable data into the history of flooding in the region, including details about how flooding impacts the region.
From the compiled repository from above, the development of meaningful map visualizations and animations for a better understanding of flooding phenomenon in the area and their impact to the ecosystem are the focus of this project.
In New Brunswick, the frequency and magnitude of flood have been increasing in recent years. Providing tools for emergency management response, public awareness and mitigation will help decision makers, emergency responders and local residents. This research team has been working towards this direction in close collaboration with Natural Resources Canada (NRCan), Public Safety Canada and the Hazus Canada initiative since 2013.
Digital Elevation models (DEM) are an integral part of flood modelling. High resolution DEM data is not always available or affordable for communities, thus other elevation data sources are explored. While the accuracy of some of these sources has been rigorously tested, (e..g.: SRTM and ASTER), others, such as NRCan's Canadian Digital Elevation Model (CDEM) and Google, Esri and Bings' Elevation REST APIs' have not yet been properly evaluated. There are several advantages to using these products, including: Canada wide coverage and machine readable data acquisition; however, limitations include lack of metadata detailing acquisition source and unreported accuracy.
The scope of this research project is two-fold: (a) evaluate the accuracy of these resources and (b) test a recently developed, novel DEM fusion method. The individual DEMs and fusion DEMs will be compared to a high-resolution Light Detection and Ranging (LidAR) surface, while flood inundation maps will be generated for a study area of high ecological significance - the Grand Lake Meadows.
Results available, published in Geomatica
Click on the image below to launch the Esri Story Map, created by fellow student: Patrick McNeil. This story map introduces describes the history of flood events in this area, including years of flooding, water depths and spatial extents in GLM. Additionally on this site the progression of flooding, from low, to moderate and high flood levels is described and visualized though both text and animation.