In geomorphology, drainage systems , also known as river systems , are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of the land, whether a particular region is dominated by hard or soft rocks, and the gradient of the land. Geomorphologists and hydrologists often view streams as part of drainage basins (and sub-basins. This is the topographic region from which a stream receives runoff, throughflow, and its saturated equivalent, groundwater flow. The number, size, and shape of the drainage basins varies and the larger and more detailed the topographic map, the more information is available. A drainage system is described as accordant if its pattern correlates to the structure and relief of the landscape over which it flows. A discordant system or pattern does not correlate to the topography and geology of the area. Discordant drainage patterns are classified into two main types: antecedent and superimposed,while anteposition drainage patterns combine the two. In antecedent drainage, a river’s vertical incision ability matches that of land uplift due to tectonic forces. Superimposed drainage develops differently: initially, a drainage system develops on a surface composed of ‘younger’ rocks, but due to denudative activities this surface of younger rocks is removed and the river continues to flow over a seemingly new surface, but one in fact made up of rocks of old geological formation. Rectangular drainage develops on rocks that are of approximately uniform resistance to erosion, but which have two directions of jointing at approximately right angles or 90 degrees. The joints are usually less resistant to erosion than the bulk rock so erosion tends to preferentially open the joints and streams eventually develop along the joints. The result is a stream system in which streams consist mainly of straight line segments with right angle bends and tributaries join larger streams at right angles. This pattern can be found with the Arun River in Nepal. Drainage is the method of removing surface or sub-surface water from a given area. Drainage systems include all of the piping within a private or public property that conveys sewage, rainwater, and other liquid waste to a point of disposal. The main objective of a drainage system is to collect and remove waste matter systematically to maintain healthy conditions in a building. Drainage systems are designed to dispose of wastewater as quickly as possible and should prevent gases from sewers and septic tanks from entering residential areas.
Residential drainage systems remove excess water from residential areas. This system helps whisk water away from walkways, driveways, and roofs to avoid flooding. Residential drainage systems are very important as they prevent rotting, mold, mildew, and structural damage in buildings from a buildup of water. Our SE exam review courses discuss the requirements and recommendations for residential structures regarding drainage systems.
The types of residential drainage systems are:
1)Surface
2)Subsurface
3) Slope
4)Downspout/gutters
Surface drainage systems contain shallow ditches dug in a parallel pattern, which act as canals for run-off water. Theses ditches lead the water into the main drain to avoid water pooling and flooding. A subsurface drainage system is also known as a French drain. Subsurface drains are placed beneath the top layer of soil to remove excess water at the root level. Subsurface drains require the digging of deep ditches and the installation of underground pipes. A large collector drain is installed to collect water from the pipes. Slope drains allow water to flow downward from a structure with the aid of pipes moving down a slope. A pipe is installed and anchored into a small incline, which causes water to flow through the pipe and away from the structure. Downspouts collect water from gutters and divert it to the ground. A downspout is typically connected to a gutter system on a building and carries water away from the roof down to the ground. Downspouts empty out the water on a slope so that the water does not pool at the base of the downspout.
Combined drainage systems use a single drain to convey both water from sanitary usage and rainwater from roofs and other surfaces to a shared sewer. This system is economical to install. Separate drainage systems use separate foul water drains that lead to a sanitary sewer. The rainwater from roofs and other surfaces is conveyed in a separate surface water drain into a surface water sewer. This system is relatively expensive to install. Our SE exam review courses thoroughly review the building and design codes to follow proper drainage system installations.