Wiktionary
n. Water collecting on the ground or in a stream, river, lake, sea or ocean, as opposed to groundwater.
Wikipedia
Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water.
Non-saline surface water is replenished by precipitation and by recruitment from ground-water. It is lost through evaporation, seepage into the ground where it becomes ground-water, used by plants for transpiration, extracted by mankind for agriculture, living, industry etc. or discharged to the sea where it becomes saline.
Usage examples of "surface water".
Adding in the appropriate amounts of nitrogen, oxygen, and surface water will come next, from comets barged down from the Kuiper Belt.
The generators' working fluid was heated to a vapour by the ocean's warm surface water, passed through turbines, then chilled and condensed by the water from the bottom.
Grazing on the grass near the woman's feet were several colorful ducks, which did seem odd, as this was the only quarter in which no surface water could be seen.
There were clumps of long, rain-flattened grass, an occasional gleam of surface water, and vast tracts of mud.
Big fishing nets were draped from the beams across the ceiling, where reflecting bulbs played like sunlight on surface water.