The Unusual and Large Drawdown Response of Buried‐Valley Aquifers to Pumping

Abstract

The buried-valley aquifers that are common in the glacial deposits of the northern hemisphere are a typical case of the strip aquifers that occur in many parts of the world. Pumping from a narrow strip aquifer leads to much greater drawdown and much more distant drawdown effects then would occur in a sheet aquifer with a similar transmissivity and storage coefficient. Widely used theories for radial flow to wells, such as the Theis equation, are not appropriate for narrow strip aquifers. Previously published theory for flow to wells in semiconfined strip aquifers is reviewed and a practical format of the type curves for pumping-test analysis is described. The drawdown response of strip aquifers to pumping tests is distinctive, especially for observation wells near the pumped well. A case study is presented, based on extensive pumping test experience for the Estevan Valley Aquifer in southern Saskatchewan, Canada. Evaluation of groundwater resources in such buried-valley aquifers needs to take into account the unusually large drawdowns in response to pumping.

Conceptual hydrogeological model of the Yonge Street Aquifer, south-central Ontario: a glaciofluvial channel–fan setting

“…The magnitude of the drawdown at Queensville is estimated at approximately 30-35 m based on reported static water levels (ϳ240-245 m asl) from the MOECC water well record database in this area prior to 1960. This estimate is also consistent with pre-municipal pumping static groundwater levels in the area of approximately 245 m asl (International Water Consultants Ltd. 1977;Vallery et al 1982). The onset of YSA pumping in Aurora in the late 1950s would have affected any initial static water levels measured in this part of the YSA when the Queensville wells were drilled several decades later.…”

Linking the morphology of fluvial fan systems to aquifer stratigraphy in the Sutlej‐Yamuna plain of northwest India

“…The types of lateral and vertical heterogeneity that characterize fan systems, including variations in grain size, porosity, mineralogy, lithologic texture, and channel body structure, will cause variations in hydraulic conductivity, storage, and porosity, and thus control flow and transport through the subsurface [ Fogg , ; Koltermann and Gorelick , ; Eaton , ]. Other studies of channel body aquifers have pointed out that ignoring the connectivity of permeable but spatially distinct channel deposits limits the ability to perform appropriate hydrogeological analysis [ Anderson , ; Fogg et al , ; Burns et al , ; Van der Kamp and Maathuis , ]. Renard and Allard [] showed that connectivity is a key influence on a wide range of groundwater flow and transport processes but is most important in areas with moderate proportions of aquifer bodies.…”

Geological framework of the Laurentian trough aquifer system, southern Ontario

“…Downhole geophysics at Nobleton reveals coarsening-upward trends in gamma and conductivity logs where sand content increases slightly (Knight et al 2008); this is consistent with inferences from geophysical logs for Scarborough Formation northward from Lake Ontario bluffs (Eyles et al 1985). Organic or gas-rich strata intercepted in drilling, such as in aquifers near Schomberg and Alliston (Turner 1977), and in core (Hockley, Beeton, and Borden), is likely from Scarborough Formation (Bajc et al 2014; see more detail in Mulligan and Bajc 2018) or from Whitby Shale. However, previous correlation of Scarborough Formation to Vandorf (180 m asl), Ballantrae (210 m asl), and Newmarket (210 m asl) (Sharpe et al 2003) is now correlated within the elevation range for TF (<150 m asl) (Table 4).…”