Water 2014, 6, 517-546; doi:10.3390/w6030517 OPEN ACCESS water ISSN 2073-4441 www.mdpi.com/journal/water Article Integrated River and Coastal Hydrodynamic Flood Risk Mapping of the LaHave River Estuary and Town of Bridgewater, Nova Scotia, Canada Tim Webster *, Kevin McGuigan, Kate Collins and Candace MacDonald Applied Geomatics Research Group, Nova Scotia Community College, Middleton, Nova Scotia B0S 1M0, NS, Canada; E-Mails:
[email protected] (K.M.);
[email protected] (K.C.);
[email protected] (C.M.) * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel.: +1-902-825-2775; Fax: +1-902-825-5479. Received: 12 December 2013; in revised form: 27 February 2014 / Accepted: 5 March 2014 / Published: 21 March 2014 Abstract: Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on the Atlantic Coast of Canada. Bridgewater is at risk of flooding due to the combined effects of river runoff and a storm surge on top of high tide. Projected increases in sea-level and possible increased river runoff with climate change increase the risk of future flooding. A set of river and ocean water level simulations were carried out to determine the risk of flooding to Bridgewater today and in the future under climate change. The hydrodynamic simulation developed incorporates return periods of a time series of river discharge measurements for the LaHave watershed, ocean water dynamics at the mouth of the river under normal tidal conditions and with two levels of storm surge, near shore and river bathymetry, as well as high precision topographic lidar derived ground elevations and survey grade GPS.