Dikes, dams, levees - Revision history

Friederike Kraemer at 11:43, 20 October 2014

2014-10-20T11:43:54Z

Christoph Wagener at 15:14, 11 November 2013

2013-11-11T15:14:03Z

Jana Herold: Created page with " A dike normally runs along or parallel to a body of water such as a river or a sea, a dam runs across or through a body of water. A dike has water only on one side, a dam has..."

2013-04-19T13:17:25Z

Created page with " A dike normally runs along or parallel to a body of water such as a river or a sea, a dam runs across or through a body of water. A dike has water only on one side, a dam has..."

New page

A dike normally runs along or parallel to a body of water such as a river or a sea, a dam runs across or through a body of water. A dike has water only on one side, a dam has water on both sides. The main purpose of a dike is protecting the land behind it from flooding (closing dike), whereas a dams' purpose is to retain the water.

Dikes and levees are embankments constructed to prevent flooding. Levees may be formed naturally or artificially. They prevent the water from overflowing and flooding surrounding areas.

Dikes are walls that hold back the sea. The land would be flooded if the dikes were broken down. The dikes were first built to reclaim land from the sea. In countries like Egypt and Bangladesh they will be needed, when the sea levels raise as it is predicted.

= References =

http://www.fao.org/DOCREP/006/T0165E/t0165e01.htm

http://wiki.answers.com/Q/What_is_the_difference_between_a_dike_and_a_dam

http://sustainablestormwater.org/2009/05/28/stormwater-101-detention-and-retention-basins/

[[Manual_of_reforestation_and_erosion_control_for_the_Philippines|GIZ (1975): Manual of reforestation and erosion control for the philippines.]]

[[Flood_control_measures|GIZ (2000): Flood control measures. Best practices report. An approach for community based flood control measures in the terai rivers.]]

@@ Line 49: / Line 49: @@
 |}
+<br/>
-−
 = Permeable Rock Dams =
@@ Line 57: / Line 57: @@
 Building permeable rock dams is a technique to restore seriously degraded farmland, forest and rangeland by filling gullies. The structure is made out of stone walls (large stones on the outer wall and smaller stones internally) that are over 1 m high within the gully it is constructed in, and 0.8-1.5 m high in the wingwalls, that are constructed as extensions on both sides of the dam. The length of the dam usually lies in between 50 and 300 m and the width of the dam is generally at least three times its height. For stability reasons, the dam wall is built flatter on the downslope side than on the upslope side and a blanket of small stones is laid as a foundation trench, which additionally reduces the risk of undermining. If the floodwater flow is very strong, it is required to build a spillway within the gully. The effect of a permeable rock dam is that the flow of floodwaters is slowed down and becomes spread over adjacent fields. So sediments build up behind the dam and fill the gully which stops lateral drainage from the adjacent land and therefore increases its productivity. Another effect is the increased infiltration of water upstream of the dam which results in a raising groundwater table in wells. The costs for a permeable rock dam may vary considerably depending on its size and the distance to the nearest quarry.
-[[File:Rock dams.jpg|left|500px]]
+[[File:Rock dams.jpg|left|500px|alt=Rock dams.jpg]]
-−
 = References =
@@ Line 72: / Line 72: @@
 [[Flood control measures|GIZ (2000): Flood control measures. Best practices report. An approach for community based flood control measures in the terai rivers.]]

@@ Line 5: / Line 5: @@
 Dikes are walls that hold back the sea. The land would be flooded if the dikes were broken down. The dikes were first built to reclaim land from the sea. In countries like Egypt and Bangladesh they will be needed, when the sea levels raise as it is predicted.
 = References =
-http://www.fao.org/DOCREP/006/T0165E/t0165e01.htm
+[http://www.fao.org/DOCREP/006/T0165E/t0165e01.htm http://www.fao.org/DOCREP/006/T0165E/t0165e01.htm]
-http://wiki.answers.com/Q/What_is_the_difference_between_a_dike_and_a_dam
+[http://wiki.answers.com/Q/What_is_the_difference_between_a_dike_and_a_dam http://wiki.answers.com/Q/What_is_the_difference_between_a_dike_and_a_dam]
-http://sustainablestormwater.org/2009/05/28/stormwater-101-detention-and-retention-basins/
+[http://sustainablestormwater.org/2009/05/28/stormwater-101-detention-and-retention-basins/ http://sustainablestormwater.org/2009/05/28/stormwater-101-detention-and-retention-basins/]
-[[Manual_of_reforestation_and_erosion_control_for_the_Philippines|GIZ (1975): Manual of reforestation and erosion control for the philippines.]]
+[[Manual of reforestation and erosion control for the Philippines|GIZ (1975): Manual of reforestation and erosion control for the philippines.]]
-[[Flood_control_measures|GIZ (2000): Flood control measures. Best practices report. An approach for community based flood control measures in the terai rivers.]]
+[[Flood control measures|GIZ (2000): Flood control measures. Best practices report. An approach for community based flood control measures in the terai rivers.]]