Difference between revisions of "How to Fight Soil Erosion"

From Howtopedia - english
Jump to: navigation, search
(→‎Smaller gullies)
 
(36 intermediate revisions by 6 users not shown)
Line 1: Line 1:
−
== How to stop gullies on eroded slopes ==
+
{{stub}}
  
−
Gully formation may be severe in areas with deep soils and steep slopes. On steep slopes the velocity of the water is very high and the scouring effect will be great. A deep soil profile with only little cohesion is susceptible to rapid and deep gully formation during heavy rainfall.
+
=How to Fight Slopes Soil Erosion?=
 +
==Short Description==
 +
*'''Problem:''' Due to deforestation or poor agricultural managment, the soil layer is being washed down by rain, causing gullies, poor agricultural conditions, and a risk for the populations.
 +
*'''Idea:''' Slowing the speed of the rain water on the slope, filtering the soil from the water and causing the particles to stay on the slope, planting deep roots plants or trees stabilizing the soil deeply, working on the horizontal contour lines.
 +
*'''Difficulty:''' Often huge surfaces concerned with the problem, work intensive solutions, necessity of an general agreement on the works within the community, maintainance.
 +
*'''Price Range:''' Accordingly to the labour intensivity, expensive
 +
*'''Material Needeed:''' Deep root trees and plants, construction material
 +
*'''Geographic Area:''' Global
 +
*'''Competencies:''' Understanding of contour lines, construction and planting skills
 +
*'''How Many people?''' From 5 to a community
 +
*'''How Long does it take?''' Depending on the slope and area concerned. labour intensive.
  
 +
==Description==
 +
The basic principles of the fight against slope erosion are to stabilize the soil through the planting of trees like or deep rooted plants like vetiver, working on the horizontal contour lines to slow the speed of the rain water on the slope, which as a midterm side effect improves the water infiltration and the groundwater levels, and to filter the washed soil particles from the flowing rainwater.<br>
 +
On relatively flat slopes, it will already be of some help to plough perpendicularly to the slope, along the contour lines.
  
 +
Contour lines are (abstract) lines that follow an horizontal path along the hill or the mountain side. They are perpendicular to the slope. Some animals create such horizontal paths: thoses paths can be an indication to recognize a contour line. An A shaped wood frame with a weighted string attached to the top angle, and a point marking the middle of the horizontal beam can be helpful to mark precisely horizontal contour lines: when the string hangs centered on the mark, the two legs of the A are at the same horizontal level.<br>
 +
Some of the traditional ways to fight soil erosion is the creation of walls or fences along the contour lines. You should consider the fact that the pressure of the rainwater flow can break the wall or at least strongly weaken it, and that there should always be a sufficient drainage to lower the pressure. Planting vetiver is a promising alternative to walls and fences as it allows the water to flow through but filters efficently soil particles and is quickly deeply rooted. Reports show that in the course of the time, natural terrasses create where vetiver was planted.
 +
It is important for terrassing walls or vetiver contours that no opening occures in the contour, that those elements are undisrrupted along the contour line, for this would mean an increased flow of water destroying parts of the construction and creating a gully.
  
−
== Purpose of gully control ==
+
==Difficulties==
  
−
The purpose of gully control is not so much erosion control as an attempt to limit the effects of erosion which is taking place upstream from the gully. Of course, existing gullies should be prevented from developing further. What measures are taken to prevent or control the process of gully formation depends on the size of the gully and the area to be drained (the amount of water to be diverged). First of all we try to check the amount of water coming into the gully by protecting the soil upstream or even by diverging the water. The velocity of the water in the gully also has to be checked so that it doesn't scour out further
+
==Success Story==
  
 +
==Plans, Illustrations, Posters==
 +
==Contacts==
 +
*WOCAT: World Overview of Conservation Approaches and Technologies.
 +
CDE WOCAT
 +
Hallerstrasse 10
 +
CH - 3012 Berne
 +
Switzerland
 +
Tel.: ++41 31 631 88 22
 +
Fax: ++41 31 631 85 44
 +
New Email-Address: wocat (at) cde.unibe.ch
 +
[http://www.wocat.net/ http://www.wocat.net]
  
−
== Smaller gullies ==
+
==Links==
  
−
Smaller gullies can be kept in check by the farmers themselves as follows: As far as possible the water is kept in the middle of the gully so that the walls cannot be undermined. In shallow gullies small dams with an overflow can be laid out with rubble, twigs, stones and wire bolsters. The water can then ooze through these fairly open constructions whereas any transported silt is held back upstream. In this way the longitudinal slope is reduced and with it the flow velocity too. If available, wire netting supported by wooden posts, can be used for smaller gullies.  
+
Link to Fourthway's poster "How to stop soil erosion": http://www.fourthway.co.uk/posters/pages/soilerosion.html
−
[[Image:gullystopping.gif|center|600px]]
 
  
−
== Larger gullies ==
+
Link to Fourthway's poster "Why Mulch?": http://www.fourthway.co.uk/posters/pages/mulch.html
  
−
For larger gullies small stone dams can be used. [[Image:strengthening-bank.gif]].Protection of the head of the gully can be done by protecting the soil with broken stone, rubble, twigs or similar material. It is also advisable to keep the area around the head of the gully planted up with trees or a tuft forming crop, for example vetiver grass. To prevent trampling by cattle (sometimes even the direct cause of gully formation) preventive measures should be taken by making a good fence (thorny hedge for example). By leading the water along the lower parts of the land you must be sure that water actually comes into the gully.
+
==Bibliography==
 +
[http://www.vetiver.org/Fiji%20Rep.pdf Pdf on evaluation of invasiveness of Vetiver in Fidji], Paul Truong & Colin Creighton
  
−
Points of attention
+
==Related articles==
−
When laying out these check dams, the following points should be taken into account:
 
−
- The principle is to shorten the length of the slope in the gully over which the water flows, so that the flow velocity (and with it the chance of further erosion) decreases.
 
−
- The gully walls at the position of the dam and also a part upstream are graded to a slope of 1:2 (going up 1 meter over a distance of 2 meters) or less, so that the chance of breaking is minimized.
 
−
- There should be good contact between the dam and the gully wall (well anchored); otherwise the temporary structure will wash away. Fencing poles are always driven deep into the soil so this applies to these structures too.
 
−
- The dam should be lowest in the middle where the flow has to concentrate at the overflow.
 
−
- The gully floor should be strengthened down stream against the scouring force of the water. This can be done by making a type of mattress or cover which is well sealed. (For example broken stone, discarded car tires filled up, concrete rubble etc.). After overflowing, the water is very turbulent. Even though the stream is concentrated in the middle of the gully, the walls will have to be extra strengthened.
 
−
- Obstacles within the gully which force the water to the sides have to be removed in order to prevent further scouring out of the sides of the gully. In certain cases, the turbulence of the water causes undermining of the head of the gully. This means that the head (starting point) of the gully cuts in further backwards (up slope). Measures have to be taken to prevent this happening.[[Image:gullycreep.gif]]
 
  
−
Agromisa, Rob Witte, 2001, also available from www.interdev-net.org
+
*[[How to Fight Soil Erosion by planting Vetiver Grass]]
 +
*[[How to Fight Soil Erosion]]
 +
*[[How to Stop Gullies on Eroded Slopes]]
 +
*[[How to Build Causeways out of Dry Stone]]
 +
*[[How to Harvest Rainwater]]
 +
*[[How to Harvest Run Off Rainwater]]
 +
*[[How to Process Nutmeg and Mace]]
 +
*[[What to Do with Neem Seeds]]
 +
*[[Ecological Sanitation]]
 +
*[[How to Start Culture in Zai Holes]]
 +
*[[How to Control Water Hyacinth]]
 +
*[[How to Recycle Rubber]]
 +
 
 +
{{Paypal}}
 +
 
 +
=='''Categories'''==
 +
 
 +
[[Category:Agriculture]]  [[Category:Communication]] [[Category:Community]][[Category:Construction]] [[Category:Crisis Management]] [[Category:Forest]][[Category:Ideas]] [[Category:Pollution]] [[Category:Prevention]]  [[Category:Resource Management]]  [[Category:Soil]] [[Category:Run-Off]] [[Category:Water]] [[Category:Water harvesting]]  [[Category:Irrigation]]  [[Category:Wind]] [[Category:Biodiversity]]
 +
[[Category:Medium]] 
 +
 
 +
[[Category:Global Technology]] [[Category:Arid Climate]] [[Category:Forest Environment]] [[Category:Global]] [[Category:Mediterranean Climate]] [[Category:Monsoon Climate]] [[Category:Rainy season]][[Category:Montaneous Environment]] [[Category:Coastal Area]] [[Category:Lakes and Rivers]] [[Category:Rural Environment]] [[Category:Temperate Climate]] [[Category:Tropical Climate]] [[Category:Urban Environment]]
 +
[[Category:Clay]] [[Category:Compost]]  [[Category:Seeds]] [[Category:Seedlings]] [[Category:Straw]] [[Category:Tea]]  [[Category:Tyres]] [[Category:Vetiver]] [[Category:Wood]]
 +
[[Category:More than 5 Persons]]
 +
[[Category:Household]] [[Category:Village]][[Category:Neighbourhood]]
 +
 +
[[Category:Application]] [[Category:Principles]] [[Category:Howtopedia requested drawings]] [[Category:Howtopedia requested images]]
 +
 
 +
[[Category:Requested translation to Spanish]]
 +
 
 +
 
 +
[[en:How to Fight Soil Erosion]]
 +
[[fr:Comment combattre l’érosion des pentes]]
 +
[[pt:Como combater a erosão do solo]]

Latest revision as of 14:56, 5 June 2017

This article is a draft. It was just started and needs further work.


How to Fight Slopes Soil Erosion?

Short Description

  • Problem: Due to deforestation or poor agricultural managment, the soil layer is being washed down by rain, causing gullies, poor agricultural conditions, and a risk for the populations.
  • Idea: Slowing the speed of the rain water on the slope, filtering the soil from the water and causing the particles to stay on the slope, planting deep roots plants or trees stabilizing the soil deeply, working on the horizontal contour lines.
  • Difficulty: Often huge surfaces concerned with the problem, work intensive solutions, necessity of an general agreement on the works within the community, maintainance.
  • Price Range: Accordingly to the labour intensivity, expensive
  • Material Needeed: Deep root trees and plants, construction material
  • Geographic Area: Global
  • Competencies: Understanding of contour lines, construction and planting skills
  • How Many people? From 5 to a community
  • How Long does it take? Depending on the slope and area concerned. labour intensive.

Description

The basic principles of the fight against slope erosion are to stabilize the soil through the planting of trees like or deep rooted plants like vetiver, working on the horizontal contour lines to slow the speed of the rain water on the slope, which as a midterm side effect improves the water infiltration and the groundwater levels, and to filter the washed soil particles from the flowing rainwater.
On relatively flat slopes, it will already be of some help to plough perpendicularly to the slope, along the contour lines.

Contour lines are (abstract) lines that follow an horizontal path along the hill or the mountain side. They are perpendicular to the slope. Some animals create such horizontal paths: thoses paths can be an indication to recognize a contour line. An A shaped wood frame with a weighted string attached to the top angle, and a point marking the middle of the horizontal beam can be helpful to mark precisely horizontal contour lines: when the string hangs centered on the mark, the two legs of the A are at the same horizontal level.
Some of the traditional ways to fight soil erosion is the creation of walls or fences along the contour lines. You should consider the fact that the pressure of the rainwater flow can break the wall or at least strongly weaken it, and that there should always be a sufficient drainage to lower the pressure. Planting vetiver is a promising alternative to walls and fences as it allows the water to flow through but filters efficently soil particles and is quickly deeply rooted. Reports show that in the course of the time, natural terrasses create where vetiver was planted. It is important for terrassing walls or vetiver contours that no opening occures in the contour, that those elements are undisrrupted along the contour line, for this would mean an increased flow of water destroying parts of the construction and creating a gully.

Difficulties

Success Story

Plans, Illustrations, Posters

Contacts

  • WOCAT: World Overview of Conservation Approaches and Technologies.

CDE WOCAT Hallerstrasse 10 CH - 3012 Berne Switzerland Tel.: ++41 31 631 88 22 Fax: ++41 31 631 85 44 New Email-Address: wocat (at) cde.unibe.ch http://www.wocat.net

Links

Link to Fourthway's poster "How to stop soil erosion": http://www.fourthway.co.uk/posters/pages/soilerosion.html

Link to Fourthway's poster "Why Mulch?": http://www.fourthway.co.uk/posters/pages/mulch.html

Bibliography

Pdf on evaluation of invasiveness of Vetiver in Fidji, Paul Truong & Colin Creighton

Related articles

Two ways to support the work of howtopedia for more practical articles on simple technologies:
 Support us financially or,
Testimonials on how you use howtopedia are just as precious: So write us !

<paypal />

Categories

Retrieved from "http://en.howtopedia.org/?title=How_to_Fight_Soil_Erosion&oldid=11215"