Technologies

Multipurpose Earthen Dam [Bangladesh]

Goda

technologies_1344 - Bangladesh

Completeness: 57%

1. معلومات عامة

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Bangladesh Forest Research Institute (Bangladesh Forest Research Institute) - Bangladesh

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

نعم

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Artificial earthen dam constructed in the narrow valley of the hills for water harvesting, aquaculture, house hold uses and irrigation.

2.2 Detailed description of the Technology

Description:

The embankment is situated in the narrowest part of the valley using soil from nearby areas. Earthen dam constructed in the narrow valley of the hiills for water harvesting,aquaculture, house hold uses and irrigation of seasonal crops. Both sides of the embankment are protected by a bamboo mat. The usual length is 30 m, width 5 m and height 1.5 m. The bund is compacted manually, easy maintenance, enviornment firendly.

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

بلد:

Bangladesh

Region/ State/ Province:

Chittagong Hill Tracts

Specify the spread of the Technology:
  • applied at specific points/ concentrated on a small area
Comments:

Total area covered by the SLM Technology is 0.004 km2.
New area interms of settlement under cooperative management system

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • as part of a traditional system (> 50 years)
Comments (type of project, etc.):

From the past generations

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • access to water

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

نعم


Cropland

Cropland

Number of growing seasons per year:
  • 2
Waterways, waterbodies, wetlands

Waterways, waterbodies, wetlands

  • Ponds, dams
Main products/ services:

water harvesting,aquaculture, house hold uses and irrigation of seasonal crops

Comments:

Major land use problems (compiler’s opinion): Most land are sloping, medium fertility, poor vegetative cover in the catchments, lack of improved technology, poor economy

Major land use problems (land users’ perception): Small amount of flat land, soil fertility degradation, lack of capital, difficult to work in the slopy area.

3.5 SLM group to which the Technology belongs

  • water harvesting
  • irrigation management (incl. water supply, drainage)

3.6 SLM measures comprising the Technology

structural measures

structural measures

  • S5: Dams, pans, ponds

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Technical knowledge required for field staff / advisors: moderate

Main technical functions: control of dispersed runoff: retain / trap

Construction material (earth): Accumulation of soil to retain water.

Construction material (wood): reinforcement of bund and to protect slumping down.

For water harvesting: the ratio between the area where the harvested water is applied and the total area from which water is collected is: 1:200.00

Layout change according to natural and human environment: depending on valley width, depth and amount of water will be researved

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Taka

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

60,0

Indicate average wage cost of hired labour per day:

1.20

4.3 Establishment activities

Activity Timing (season)
1. Bamboo structure preparation and earth working 2 days
2. earth work 5 days
3. Prepare out-let 1
4. Compacting bund 2
5. wooden poles piling , setting bamboo mat and soil dumping 2-4 days

4.4 Costs and inputs needed for establishment

Comments:

Duration of establishment phase: 12 month(s)

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Filling-up depressions formed during previous rainy season 2 days/annual
2. Reparing bamboo mat 2/annual
3. filling up with soils, protecting water likage,repairing bamboo mats etc. 1-2 days / 1-2 times in a year

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Comments:

Bands structure with length,width & height

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Dam construction and maintenance

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specifications/ comments on rainfall:

Seldom goes more than 3000

Agro-climatic zone
  • humid

Prevail monsoon climate

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms:
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Comments and further specifications on topography:

Slopes on average: Narrow valley are generally with less slope gradient.Hilly slopes surrounding the reservoir

Landforms: Slopes are varaible and valleys are mostly V-shaped and narrow

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • medium (loamy, silty)
  • fine/ heavy (clay)
Topsoil organic matter:
  • medium (1-3%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil texture (topsoil): Depends on the the soils of the catchments but fine soils are commonly washed out from upper catchments.

Soil fertility is medium and depends on the the soils of the catchments

Topsoil organic matter: High rainfall washes out top soil under thinly covered soil

Soil drainage / infiltration is poor in the valleys

Soil water storage capacity is high in finer soils and around the dam and medium if the soil are coarse

5.6 Characteristics of land users applying the Technology

Off-farm income:
  • less than 10% of all income
Relative level of wealth:
  • average
Indicate other relevant characteristics of the land users:

Population density: 10-50 persons/km2

Annual population growth: 2% - 3%

30% of the land users are average wealthy and own 4% of the land (own minimum 5 acre of land).

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • individual, titled
Land use rights:
  • individual

6. Impacts and concluding statements

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

slightly positive

Long-term returns:

positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

slightly positive

Long-term returns:

positive

6.5 Adoption of the Technology

  • 1-10%
If available, quantify (no. of households and/ or area covered):

5 households covering 10 percent of stated area

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 91-100%
Comments:

5 land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: survey results

There is a strong trend towards spontaneous adoption of the Technology

Comments on adoption trend: Due to higher benefits shown by the technolgy in the farmering site

7. References and links

7.1 Methods/ sources of information

Links and modules

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