In British Columbia (BC), Canada, the Water Sustainability Act requires statutory decision-makers to consider impact of well pumping on stream flows in allocation decisions. This requires sufficient understanding of where hydraulic connection occurs between the stream and the aquifer, and the expected timing of impacts on streamflow and on other users. Understanding hydraulic connection and streamflow depletion from well pumping is challenging in BC because comprehensive studies are costly, time-consuming, and prior to 2016, not required because diversion and use of groundwater were not licensed. This presentation describes the use of available topographic, geologic, and historic well record information to map the presence/absence of the vadose zone and confining layer thicknesses beneath streams to infer where hydraulic connection is likely to exist. Mapping groundwater flow allows impacts on connected stream reaches from well pumping to be identified. Availability of aquifer hydraulic parameters allows timing of pumping impacts to be calculated. This preliminary desk-top mapping approach was applied to various streams on Vancouver Island, in the Lower Fraser Valley, and in the Interior of BC to infer the likelihood of connection between streams and underlying unconsolidated and fractured bedrock aquifers that are sources of groundwater supply locally. These assessments provide a physically based rationale for decision makers to curtail groundwater use to protect streamflow during times of water scarcity and a hydrogeological framework for additional data collection efforts to improve understanding of streamflow depletion from pumping in the watershed.