A horizontal conduit for intercepting and collecting ground water by gravity flow. A subsurface ground water collection system, typically shallow in depth, constructed with open-jointed or perforated pipes that discharge collected water into a water-tight chamber. From this chamber the water is pumped to treatment facilities and into a distribution system. Infiltration galleries are usually located close to streams or ponds and may be under the direct influence of surface water. A horizontal well or subsurface drain that intercepts underflow in permeable materials or infiltration of surface water.