 Nonetheless, a few areas serve as surface water reservoirs, allowing for some groundwater regeneration, given the almost impermeable soils.The Trafalgar Moraine is approximately 20 km long, 30 m high and 4 km wide, extending from the Niagara Escarpment north of Nelson to Streetsville in an east-northeast trend; at the Oakville boundary, the trend shifts northeast.The moraine has impacted the flow of the eastern branch of the 16 Mile Creek.