Infiltration gallery
Encyclopedia
An infiltration gallery is a structure including perforated conduits in gravel to expedite transfer of water to or from a soil aquifer
.
While the catchbasins under sewer grates work well on swift-flowing surfaces like asphalt and concrete, heavy storm water flow on grass lawns or other open areas will pool in low areas if there is no outlet. An infiltration gallery serves this purpose in two ways.
Primarily, upright plastic pipe
s capped with simple grates are placed every 5-8 metres along the low point of a slope, to handle heavy surface runoff
. The pipes proceed straight down, about two metres, to a horizontal cross-pipe; this pipe is the secondary system.
The horizontal pipe is then perforated slightly (about 10% of its surface area) and surrounded by gravel
. Initially, runoff will exit the pipe and infiltrate the gravel to the soil beyond, dissipating naturally. As flow increases, the water will eventually fill the pipe and need to be dissipated more quickly. Thus, a catchbasin is placed at the lowest point of the sloping ground, which is connected to the storm sewer system at large.
Such galleries are a relatively new development in urban planning
, and are thus found in newer housing developments.
. Water from an infiltration gallery has the advantage of bank filtration
to reduce the water treatment
requirements for a surface withdrawal. An infiltration gallery may also be the best way to withdraw water from a thin aquifer or lens of fresh water overlying saline water.
Aquifer
An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...
.
Storm water disposal
Infiltration galleries may be used to supplement a storm sewer, by directing storm runoff from non-road areas.While the catchbasins under sewer grates work well on swift-flowing surfaces like asphalt and concrete, heavy storm water flow on grass lawns or other open areas will pool in low areas if there is no outlet. An infiltration gallery serves this purpose in two ways.
Primarily, upright plastic pipe
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...
s capped with simple grates are placed every 5-8 metres along the low point of a slope, to handle heavy surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
. The pipes proceed straight down, about two metres, to a horizontal cross-pipe; this pipe is the secondary system.
The horizontal pipe is then perforated slightly (about 10% of its surface area) and surrounded by gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
. Initially, runoff will exit the pipe and infiltrate the gravel to the soil beyond, dissipating naturally. As flow increases, the water will eventually fill the pipe and need to be dissipated more quickly. Thus, a catchbasin is placed at the lowest point of the sloping ground, which is connected to the storm sewer system at large.
Such galleries are a relatively new development in urban planning
Urban planning
Urban planning incorporates areas such as economics, design, ecology, sociology, geography, law, political science, and statistics to guide and ensure the orderly development of settlements and communities....
, and are thus found in newer housing developments.
Water supply
Infiltration galleries may be used to collect water from the aquifer underlying a riverRiver
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
. Water from an infiltration gallery has the advantage of bank filtration
Bank filtration
Bank filtration is a type of filtration that works by passing water to be purified for use as drinking water through the banks of a river or lake. It is then drawn off by extraction wells some distance away from the water body...
to reduce the water treatment
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
requirements for a surface withdrawal. An infiltration gallery may also be the best way to withdraw water from a thin aquifer or lens of fresh water overlying saline water.