Groundwater conditions beneath 11 hectares property owned by HydroOne near the southeastern edge of the Oak Ridges Moraine were assessed for contamination susceptibility using groundwater and geological information from HydroOne monitoring on-site and within one kilometre. Geological information was obtained from preexisting well records and a deep cored hole through dense glacial deposits (Newmarket Till) and through two deep regional sand aquifers (Thorncliffe and Scarborough Aquifers) into shale at 130 mbgs. The multiple data types included water levels, Tritium-Helium groundwater dating, oxygen-18 and deuterium, and major and minor ions. The water table is close to surface (<3m) and wells above 22 m depth in the highly active shallow zone show chemicals and Coliform Bacteria from human activities including roads, septics and agriculture. Shallow groundwater flows downward towards the Thorncliffe aquifer; the bottom of this most active zone is unknown due to insufficient data from deeper wells. Two private wells (100 mbgs) thought to be in the Thorncliffe aquifer contain constituents indicative of human influence. Seven of eight homeowner wells show tritium from nuclear power stations, one at detection limit. Three hypotheses are proposed to explain the susceptibility of wells in the Thorncliffe Aquifer to contamination: 1) the Newmarket aquitard is contains preferential pathways due to fractures connected to sand layers allowing deep penetration of contamination, 2) recharge can occur directly into the Thorncliffe aquifer in areas where Newmarket Till is non-existent, and 3) wells have faulty construction allowing short-circuiting to depth of contaminated shallow water down and along well casings. Based on the current data preferential pathways through the Newmarket is the most plausible hypothesis. However, additional work to define groundwater flow paths both on and off-site as well as additional geochemical and isotopic analyses from existing and new deep wells is needed to better determine risk to residential wells. / Thesis / Master of Science (MSc) / A groundwater study was conducted in an eight square kilometre area at the southeast edge of the Oak Ridges Moraine near Oshawa, ON. It included: geology from a 130m hole through overburden (including Newmarket Till) to bedrock, groundwater age determinations and water chemistry obtained by Hydro One from 16 monitoring wells on HydroOne property (11 hectares) and 25 nearby homeowner wells, most less than 22m deep. Wells above 22m show salt and other constituents from roads, septics or agriculture and show young groundwater age. Two deep wells (100m) in the Thorncliffe Aquifer beneath the Newmarket Till also show these chemicals; one of them sampled for tritium-helium showed young age, as do some intermediate -depth wells. The pathways for young water migrating so deep are undetermined.

Aquifers associated with the Oak Ridges Moraine (ORM) supply drinking water to more than 200,000 people. These aquifers are often overlain by relatively lower permeability till deposits (aquitards) often considered to provide protection to underlying aquifers. A transformer station is under construction by Hydro One (H1) on 11 hectares of H1 owned land on the ORM in the Municipality of Clarington, Ontario. The surficial geology is mapped as till. It is important to consider potential groundwater impacts of this transformer project. As part of the environmental assessment conducted by H1, groundwater information was collected from the property and from nearby homeowner wells. This thesis concerns the geology and groundwater conditions beneath the property utilizing both existing information and also study of a drill hole, commissioned by H1, continuously cored into bedrock at 127.76 m depth. There is a paucity of deep hydrogeological information over the eastern half of the ORM. This thesis reports on the hydrogeology of the local area, which is in a hydrologic setting common throughout much of the ORM, thereby providing valuable information to inform the regional context. The cored hole showed the presence of two deep regional sand aquifers, known as the Thorncliffe and Scarborough aquifers, overlying bedrock. The surficial till unit is interpreted to be over 75 m thick and includes a near-surface sand layer and two deeper, thin sandy layers within this very dense till. This study, conducted as a collaboration between the Universities of Guelph and McMaster, represents the first phase of a continuing study of the hydrogeology of the H1 property and adjacent area. The next phase includes installation of a depth-discrete, multilevel monitoring system (MLS) for water level measurement and groundwater sampling at 16 different depths. This thesis includes a design for this MLS to be installed beside the deep hole. / Thesis / Master of Science (MSc) / This thesis concerns the geology and groundwater conditions at the Hydro One transformer station under construction in the Municipality of Clarington, located near the southwestern periphery of the Oak Ridges Moraine (ORM). The ORM, throughout its full extent north of Lake Ontario, has aquifers supplying drinking water to more than 200,000 people, some near the transformer station. The thesis, which is the first phase of a longer term study, uses information obtained from a borehole that provided continuous core samples from near ground surface down through deposits formed by Pleistocene glaciers and into the shale bedrock at 127 m depth. This borehole and four monitoring wells installed by Hydro One nearby, provide the first deep groundwater information of its type available from this part of the ORM and indicate the presence of two deep regional sand aquifers and suggest the occurrence of two thin intermediate depth sand aquifers.

<p> The Dundas Valley is a deep bedrock valley underlying the Hamilton-Wentworth region of southern Ontario that has been infilled with up to 180m of Quaternary sediment. These sediments contain a valuable record of past environmental change, as well as control groundwater and contaminant migration pathways throughout the region. Unfortunately, the nature, origin and spatial distribution of sedimentary units comprising the infill are poorly understood. This thesis demonstrates the use of 3-D modeling of subsurface geological data obtained from water well and borehole records, engineering and construction reports to delineate the form and geometry of the sedimentary infill of the Dundas Valley. ROCKWORKS 2002 is used to analyze and model over 2000 data points and create a variety of 3-D images used as an aid to the interpretation of the late Quaternary geological history of the study area. </p> <p> Sediments identified within the valley include fine-grained diamicts, clays, silty clays, sands, gravels and silty sands. These sediment types are grouped into five stratigraphic units that record changing environmental conditions during the late Quaternary. Unit 1 represents the eroded Paleozoic bedrock surface and is overlain by a patchy veneer of sandy gravel (Unit 2), probably deposited under fluvial or shallow lacustrine conditions. Fine-grained deposits of Unit 3 record glacially-influenced lacustrine deposition in the Dundas Valley, possibly during a subsequent episode of ice advance. Unit 4 consists of coarse-grained nearshore deposits associated with the development of post-glacial Lake Iroquois and uppermost silts and sands of Unit 5 record the development of protected lagoonal conditions at the western end of the Ontario basin. </p> <p> The 3-D images of the Dundas Valley infill are also used to identify and delineate the geometry of aquifers and aquitards and to help predict potential directions of groundwater flow and potential contaminant movement. </p> / Thesis / Master of Science (MSc)

The purpose of this study is to assess the engineering geological and geotechnical characteristics and to perform seismic hazard studies of the Upper Pliocene to Quaternary (Plio-Quaternary) deposits located towards the north of Ankara through surface wave testing methods. Based on a general engineering geological and seismic site characterization studies, site classification systems are assigned in seismic hazard assessments. The objective of the research is to determine the regional and local seismic soil conditions (i.e., shear wave velocities, soil predominant periods and soil amplification factors) and to characterize the soil profile of the sites in this region by the help of surface geophysical methods. These studies have been supported by engineering geological and geotechnical field studies carried out prior to and during this study. By integrating these studies, local soil conditions and dynamic soil characteristics for the study area have been assessed by detailed soil characterization in the region. As a result, seismic hazard assessments have been performed for &Ccedil / ubuk and its close vicinity with the aid of Geographical Information Systems (GIS) through establishing seismic characterization and local soil conditions of the area.

The purpose of this study is to assess the engineering geological and geotechnical characteristics and to perform seismic hazard studies of the Upper Pliocene and Quaternary deposits located towards the west of Ankara. Based on a general engineering geological and seismic characterization of the site, site classification systems are assigned for seismic hazard assessment studies. The objective of the research is to determine the regional and local seismic soil conditions, predominant periods and ground amplifications, and to idealize the soil profile of the sites by the aid of surface geophysical methods. These studies are combined and integrated with the geotechnical database from a variety of in-situ and laboratory studies that are compiled from present and previous studies regarding the project area and then transferred to an analytical environment for creating relevant information for our site. Then, engineering geological and geotechnical seismic characterization along with seismic zoning map preperation is accomplished. Finally, based on a general engineering geological and geotechnical site characterization, site classification systems are assigned to account for site effects in seismic hazard assessments along with the assessment of mitigation and remediation of seismic hazards.

No description available.