CATARAQUI Source Protection Area CataraquiCataraqui SourceSource ProtectionProtection AreaArea FFrontenacrontenac IslandsIslands GroundwaterGroundwater andand AquiferAquifer CharacterizationCharacterization StudyStudy OctoberOctober 20072007 Executive Summary The Cataraqui Source Protection Area (CSPA) covers a large area in southeastern Ontario that includes the jurisdiction of the Cataraqui Region Conservation Authority (CRCA) plus the Township of Frontenac Islands (Figure 1). The CRCA and the Township are working together to coordinate local source water protection efforts under the Ontario Clean Water Act, 2006. The Township of Frontenac Islands is located where Lake Ontario flows into the St. Lawrence River, and it includes Wolfe Island and Howe Island, as well as several smaller islands such as Garden Island and Simcoe Island (see Figure 1). Groundwater studies were completed for the Western Cataraqui Region (Trow Associates Inc. 2007) and the United Counties of Leeds and Grenville (Dillon Consulting Limited 2001) however, information regarding the geology and hydrogeology of the Frontenac Islands was not included in either of these reports because the Frontenac Islands are not part of the CRCA jurisdiction. This report summarizes the local geology and groundwater conditions, assesses the groundwater use, and discusses data gaps that exist throughout the Frontenac Islands. The report has been prepared in accordance with the terms of reference for groundwater studies developed by the Ontario Ministry of the Environment (2001). It will be used as a technical reference document for the local source protection plan. The geology of the Frontenac Islands mainly consists of Paleozoic limestones of the Gull River, Bobcaygeon, and Verulam Formations that are overlain by thin glacial overburden. The Paleozoic limestones overlie the granites and migmatites of the Precambrian shield and, occasionally, sandstone of the Nepean (Potsdam) Formation (see Figure 5). Overburden thicknesses are generally thin, except for a significant portion of Howe Island and the eastern arm and a pocket towards the western end of Wolfe Island. Hydrogeological data for the Frontenac Islands is generally quite limited. However, it is known that the water table is generally shallow and that salty and sulphurous water pockets exist throughout the islands, especially in the Bobcaygeon and Gull River Formations. An interpretation of the Water Table Elevation Map (see Figure 9a) indicates that groundwater generally flows to the south and discharges into Lake Ontario and the St. Lawrence River. The aquifer vulnerability will be studied in detail in the Cataraqui Groundwater Vulnerability Assessment Report (GVAR) that will be complete by the Fall of 2007. i Groundwater usage on the Frontenac Islands is generally limited to domestic, private and agricultural uses. The domestic groundwater use on Wolfe Island is 7.4 x 104 m3/year, and on Howe Island is 3.5 x 104 m3/year. The estimated annual agricultural water use on Wolfe Island is 3.6 x 104 m3, and on Howe Island is 9.5 x 103 m3. There have been 14 Permits to Take Water (PTTW) on the Frontenac Islands; however, only one is a groundwater taking on Wolfe Island, and one is a combined groundwater and surface water taking on Howe Island. There is a general lack of high quality hydrogeological data for the Frontenac Islands, which leads to a poor overall understanding of groundwater flow direction and groundwater quality. It is therefore recommended that a provincial groundwater monitoring network (PGMN) well be drilled on each of the Frontenac Islands. In addition, a comprehensive collection of a suite of geochemical samples, similar to that of the Western Cataraqui Study (Trow Associates Inc., 2007) would significantly increase the understanding of the groundwater quality on the Frontenac Islands. ii Table of Contents 1.0 Introduction _____________________________________________________ 1 1.1 Water Well Information System (WWIS) ________________________________ 1 2.0 Local Geology and Groundwater Conditions ___________________________ 1 2.1 Topography and Physiography _________________________________________ 1 2.2 Geology _____________________________________________________________ 2 2.2.1 Precambrian Geology ______________________________________________________ 2 2.2.2 Paleozoic Geology _________________________________________________________ 3 2.2.3 Surficial Geology __________________________________________________________ 5 2.2.4 Geological Cross-Sections ___________________________________________________ 6 2.3 Hydrogeological Conditions ____________________________________________ 8 2.3.1 Groundwater Flow _________________________________________________________ 8 2.3.2 Groundwater Quality ______________________________________________________ 10 2.3.3 Aquifer Vulnerability _____________________________________________________ 10 3.0 Groundwater Use Assessment ______________________________________ 11 3.1 Scoping Study for Drinking Water Systems in Marysville, Wolfe Island ______ 14 4.0 Data Gaps ______________________________________________________ 16 5.0 Conclusions ____________________________________________________ 17 6.0 References _____________________________________________________ 18 Appendix A ___________________________________________________________ 19 Note: This study has received funding support from the Ontario Ministry of the Environment through the source water protection project at the Cataraqui Region Conservation Authority. Such support does not indicate endorsement by the Ministry of the contents of this material. This report was received by the Cataraqui Region Conservation Authority through its Resolution XX – 07 on May 23, 2007, and was then shared with the Township of Frontenac Islands. iii List of Tables Table 1. Water Quality Descriptors from the WWIS on the Frontenac Islands. ______ 10 Table 2. Well Use Breakdown on Wolfe and Howe Islands _____________________ 11 Table 3. PTTW Breakdown on Wolfe and Howe Islands. _______________________ 12 Table 4. Annual Agricultural Water Use (m3) on Wolfe and Howe Islands (de Loe, 2002). _____________________________________________________________________ 13 Table 5. Overall Groundwater Use on Wolfe and Howe Islands. _________________ 13 Table 6.Water Budget Parameters for Wolfe and Howe Islands. __________________ 14 Table 7. Comparison of Water Use and Recharge. _____________________________ 14 iv List of Figures Figure A.1. Exposed shallow bedrock of the Gull River Formation on Howe Island. _ 20 Figure A.2. Exposed bedrock of the Gull River Formation on Howe Island displaying dominant vertical fractures. ______________________________________________ 20 Figure A.3. Landfill site on Wolfe Island (that was a quarry) is located near adjacent to Lake Ontario in the Gull River Formation. ___________________________________ 21 Figure A.4. Bedrock outcrop of the Gull River Formation along the northeast shoreline on Wolfe Island. _______________________________________________________ 21 Figure A.5. Shallow bedrock of the Bobcaygeon Formation on Wolfe Island. _______ 22 Figure A.6. Shallow bedrock, of the Bobcaygeon Formation, and drainage ditch on Wolfe Island. _______________________________________________________________ 22 Maps Figure 1. Frontenac Islands Base Map Figure 2 Frontenac Islands Topography Figure 3 Frontenac Islands Drainage Map Figure 4 Frontenac Islands Physiography Figure 5 Frontenac Islands Bedrock Geology Map Figure 6 Frontenac Islands Surficial Geology Map Figure 7 Frontenac Islands Overburden Thickness Map Figure 8 Frontenac Islands Geological Cross-Sections Figure 9 Frontenac Islands Depth to Water Map Figure 9a Frontenac Islands Water Table Elevation Map Figure 10 Frontenac Islands Aquifer Classification Map Figure 11 Frontenac Islands Well Location Map Figure 12 Frontenac Islands Permit to Take Water Locations Figure 13 Frontenac Islands Agricultural Well Uses v 1.0 Introduction The Cataraqui Source Protection Area (CSPA) covers a large area in southeastern Ontario that includes the jurisdiction of the Cataraqui Region Conservation Authority (CRCA) plus the Township of Frontenac Islands (Figure 1). The CRCA and the Township are working together to coordinate local source water protection efforts under the Ontario Clean Water Act, 2006. Source water protection aims to help protect clean and plentiful drinking water for present and future generations. The Act envisions the preparation and implementation of science-based, locally-led source protection plans on a watershed basis. A source protection plan will be prepared for the CSPA over the next few years. The Township of Frontenac Islands is located where Lake Ontario flows into the St. Lawrence River, and it includes Wolfe Island and Howe Island, as well as several smaller islands such as Garden Island and Simcoe Island. Groundwater studies were completed for the Western Cataraqui Region (2007) and the United Counties of Leeds and Grenville (2001) however, information regarding the geology and hydrogeology of the Frontenac Islands was not included in either of these reports because the Frontenac Islands are not part of the CRCA jurisdiction. This report summarizes the local geology and groundwater conditions, assesses the groundwater use, and discusses data gaps that exist throughout the Frontenac Islands. The report has been prepared in accordance with the terms of reference for groundwater studies developed by the Ontario Ministry of the Environment (2001).