Drainage Area


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Drainage Area: drainage basin

drainage area

[′drān·ij ‚er·ē·ə]
(hydrology)

Drainage Area

 

(also hydrographical basin), a land surface, bounded by a divide, whose discharge goes into a basin. The structure of the drainage area (terrain, the presence of lakes and swamps, and the type of vegetation) considerably influences the discharge of water. The nature of the terrain of a drainage area determines the hydraulic gradient and the density of the river and valley network—that is, the speed of runoff on slopes and the rate of water flow in channels. The presence of various closed depressions causes some surface water to be held in these depressions, to be lost to evaporation and seepage, and to begin to flow into a channel only after it has filled the depressions.

drainage area

An area having a drainage channel beneath the surface.
References in periodicals archive ?
The target area of high-medium-differentiated mid-thoracic ESCC radiotherapy includes only the mid-mediastinal lymph node drainage region, and that of high-medium-differentiated lower-thoracic ESCC radiotherapy includes the lymph node drainage area in the middle and lower mediastinal and abdominal regions; and the radiotherapy target area of poorly differentiated mid-thoracic esophagus squamous carcinoma includes the mid-mediastinal and abdominal lymphatic drainage area, and that of poorly differentiated lower-thoracic ESCC includes the lymph node drainage area of the middle and lower mediastinal and abdominal areas.
As stated by Costa (1987), the number of flood events greatly reduces as a function of drainage area A and drainage density [D.sub.d] and flood peak tends to increase as a function of elongation ratio [R.sub.e].
Our hypothesis is that estimates of the slope as well as drainage area are influenced by resolution, especially on relatively flat ground, like a peat land.
Field drainage area that flows into the stormwater outfall at Slip 4 is the key issue, officials agree.
Explanatory variables included in the procedure were feedlot drainage area (ha), vegetative filter strip:drainage area ratio, vegetative filter strip age (years), vegetative filter strip slope (%), total annual (1998) rainfall depth at each site (mm), total site rainfall depth over study period (mm), event rainfall depth (mm), and estimated vegetative filter strip inflow volume ([m.sup.3], based on curve number of 91).
Helen, a teacher from Bangor, Co Down, fell into a drainage area and escaped with serious back and internal injuries.
The proposed indicator is used as an independent variable to enhance the strength, as quantified by [R.sup.2] values, of regression relationships between empirical observations of instream pollutant concentrations and land type, by considering the spatial distribution of key land-type categories within the sample point's drainage area. We present an indicator that, when used in conjunction with a variable describing the proportion of the land type, adds a new dimension of explanatory power.
The size of the rain garden depends on the size of the drainage area. The Virginia forestry department recommends a garden that is 5 to 7 percent of the drainage area.
The Mekong River is the world's 12th longest system, with a total length of 4,400 kilometers, a drainage area of 795,000 sq.
A GIS (Geographic Information System)-based approach was used to delineate the drainage area above each site and determine the land use characteristics of the sub-watershed.
The ditch is in the Beasley agricultural drainage area in Mississippi and is one of three watershed/lake combinations being studied as part of the Mississippi Delta Management Systems Evaluation Area (MDMSEA).
To keep Grand Forks, North Dakota from flooding for 20 days, you'd need to restore about six percent of the drainage area to wetlands, notes Hulsey.