Sam Ziemann From - Region of Waterloo

HYDROGEOLOGICAL ASSESSMENTSTRANGE STREET WATER SUPPLY CLASS EA UPDATEREGIONAL MUNICIPALITY OF WATERLOOBackground ReviewMarch 19, 2012Aquitard 2 (ATB3):Aquitard 2 (ATB3) corresponds to the lower Maryhill Till and represents one of the primaryregional hydrostratigraphic units. The till has been broken down into a Middle and LowerMaryhill Till by Bajc and Shirota (2007). Along the flanks of the moraine the Maryhill Till is oftenfound to be discontinuous, or has been re-worked and re-deposited as glaciofluvial sediments.Within the Strange Street Well Field, it was found to be continuous and range in thickness from5 m to 25 m (Stantec, 2009). It is defined as a clayey silt to silty clay till, physically separatingthe upper aquifer system (Aquifer 1) from the lower aquifer systems (Aquifers 2 and 3)(Figure 4).Aquifer 2 (AFB3/AFC1):Aquifer 2 corresponds to the lower Waterloo Moraine Stratified Sediments (AFB3) and CatfishCreek Drift (AFC1) as referred to by Karrow (1993), and when present is found belowAquitard 2, mainly along the eastern flank of the Moraine. This unit consists of stratified gravels,sands, or silts and is of very limited extent. As a result Aquifer 2 was rarely identified within theStrange Street Well Field (Stantec, 2009).Aquitard 3 (ATC1/ATC2):Aquitard 3 corresponds to the Catfish Creek Till. Bajc and Shirota (2007) divided this unit intoan upper (ATC1) and lower aquitard (ATC2), with Aquifer 2 (AFC1) found occasionally betweenthe two units. This unit is nearly continuous throughout the Region and together withAquitard 2, forms the main stratigraphic marker units within the Moraine. The texture of this unitis a stony, silty to sandy till, and is often referred to as “hardpan” in well logs. Within theStrange Street Well Field, ATC1 is interpreted to be continuous, with ATC2 rarely beingidentified, which could partially be a function of the limited number of deep boreholes in the area(Figure 4). Often, Aquitard 3 directly underlies Aquitard 2, likely providing an effective confininglayer between Aquifer 1 and Aquifers 3 and 4.Aquifer 3 (AFD1/AFF1):Aquifer 3 is spatially discontinuous throughout much of the core areas of the Waterloo Moraine,and is found either directly overlying bedrock or overlying Aquitard 4. AFD1 likely correspondsto sands and gravel re-worked from Catfish Creek and Pre-Catfish Creek Tills, and representsthe main supply aquifer in the Cities of Kitchener and Waterloo with the Greenbrook, Parkway,and William Street Well Fields all completed in this unit (Bajc and Shirota, 2007). AFF1 isinterpreted to correspond to the sand and gravel units typically found beneath Aquitard 4,directly overlying bedrock. This unit is discontinuous throughout the Region, and where presentis hydraulically connected with the upper weathered portion of the bedrock aquifer.Due to the limited information available from high reliability, deep borehole logs, interpretation ofthe geologic units below ATC1 is difficult (Stantec, 2009). Often, because not all these lowerunits were identifiable, distinguishing between similar aquifer units (i.e. AFC1, AFD1, and AFF1)hls v:\01609\active\161110897_strange_st\planning\report\final hydrogeo assessment\final\fnl_rpt_120319.docx 2.5