Legal Definitions - diffused surface water

Diffused surface water refers to water that originates from precipitation (such as rain or melting snow) and flows across the surface of the ground without a defined, permanent channel like a stream, river, or lake. It moves across the land in a broad, unconfined sheet or in temporary, shallow rivulets, eventually evaporating, soaking into the ground, or reaching an established watercourse or drainage system. This type of water is temporary and lacks the fixed boundaries of a natural waterway.

• Example 1: Agricultural Runoff

  After a significant rainstorm, water flows across a large, cultivated farm field. This water doesn't immediately enter a ditch or stream; instead, it spreads out over the soil, slowly moving downhill in a broad, thin sheet before eventually collecting in a drainage culvert at the field's edge.

  This illustrates diffused surface water because the rainwater is moving across the land in an unchanneled, temporary manner, not within a permanent, defined watercourse, until it is captured by an artificial drainage system.

• Example 2: Urban Stormwater

  During a heavy downpour in a residential neighborhood, rainwater cascades off rooftops, runs across driveways, and flows over lawns. Before this water enters the street gutters or storm drains, it moves across these various surfaces in an unconfined way, often pooling temporarily or sheeting across yards.

  This scenario demonstrates diffused surface water as the rainwater is flowing broadly over both natural and impervious surfaces without a fixed, natural channel, prior to being collected by engineered drainage infrastructure.

• Example 3: Hillside Snowmelt

  On a gentle, undeveloped hillside after a warm spell, the melting snow does not immediately form a stream. Instead, the water trickles and spreads across the sloped terrain, saturating the topsoil and moving as a thin, unconfined layer over the ground's surface, gradually making its way towards the base of the hill.

  Here, the melted snow constitutes diffused surface water because it flows across the land in an unchanneled, temporary fashion, not within a defined stream bed, until it might eventually consolidate into a more permanent body of water or soak into the ground.