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Technologies
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Local indigenous dyke for water harvesting [Lao People's Democratic Republic]

technologies_2306 - Lao People's Democratic Republic

Completeness: 88%

1. General information

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

Key resource person(s)

land user:

Sengmany

02096124255

Tangnong village, Dakchaung district, Sekong province

Lao People's Democratic Republic

land user:

Sekhamphone Yangmao

0309946972

Tangnong village, Dakchaung district, Sekong province

Lao People's Democratic Republic

SLM specialist:
Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
Scaling-up SLM practices by smallholder farmers (IFAD)
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
National Agriculture and Forestry Research Institute (NAFRI) - Lao People's Democratic Republic

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

11/05/2017

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

Ja

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

Nee

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

A Local Indigenous Weir to Harness Water

2.2 Detailed description of the Technology

Description:

Local villagers initiated the construction and use of communal weir with locally available materials such as wood and stones to create structure and stabilize the weir. Previously, the local people had constructed several irrigation weirs on a particular stream with each one being adjacent to an individual farm. However this arrangement created water use conflicts, particularly during dry season. Therefore people decided to group together in 2003 in order to build a communal weir and vowed to maintain it on an annual basis. This was a significant commitment as often it is difficult to find the necessary construction materials for the weir’s upkeep.
The main features and components of its framework should be prepared in the following manner: Firstly prior to beginning the weir’s construction one should gather rattan with length of 1-1.5 meters to tie the logs with each posts, as well as post with a diameter approximately 10 cm that should be cut to a length of 1.5 meters. The posts should then be sharpened at the end so that they can ideally be driven 50 cm into the ground, but this will depend on the conditions at the weir site. There should be a distance of 50 cm between each of the posts and these should be installed in two parallel rows with a space of 1 meter between the rows each rows width 1 meters and height 1 meter from the ground that cross the stream about 25 meters long.
Once this has been completed logs with diameter about 20 cm and a length of 4-5 meters should be slotted behind the rows posts and lay the another logs on the previous post until reach to the top of the post as the first layer. The second layer behind the logs should consist of small stones, soil, as well as branches and sticks. This procedure should be completed until the wall of horizontal logs has reached the height 1 meter of the top of the posts. Afterwards large stones should be placed as the top layer of the weir’s crest in order to strengthening the weir from flash flood. After that continue repeating the same process for the second row, driven the posts into the ground for 50 cm in front of the first row with distance of 1 meter and lower than first low for 50 cm, slotted behind the rows posts as the first layer. The second layer behind the logs (in front of the first row) consist small stones, soil, branch and sticks. Finally install large stones on the ground in front of the second row in order to strengthening and prevent leakages at bottom of the weir until reaching the required height. For instance, install the first row, then the second row is installed same as the first row in which the height of the second row is lower than the first row about 50 cm, and install large stones on ground of the third row to prevent leakages at bottom of the weir.

The main purpose of the weir is to provide an adequate water supply for agricultural activities in communal areas. Some households have also installed a dynamo (electric generator) with a production capacity of 1 Kwh. It should be noted that it is important to maintain the weir by regularly replacing the logs and adding more stones as required. One of the benefits of the weir is the ability to carry out agricultural activities in both the rainy and dry seasons. Furthermore water can be used for household gardening and the generation of electricity with the installation of a small dynamo where a channel with fast running water has been created. However, the weir does also have some drawbacks such as the significant numbers of logs that are required to firstly build and then maintain the weir annually. Therefore some land owners or land users may not choose this scheme due to these regular maintenance requirements with the need for logs which are declining in numbers and becoming increasingly difficult to source. At the same time this requirement may also affect forest resources and places time pressure on people to conduct the maintenance.

2.3 Photos of the Technology

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

Country:

Lao People's Democratic Republic

Region/ State/ Province:

Tangnong village, Dakchaung district, Sekong province

2.6 Date of implementation

Indicate year of implementation:

2003

If precise year is not known, indicate approximate date:
  • 10-50 years ago

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • as part of a traditional system (> 50 years)

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • improve production
  • reduce risk of disasters
  • adapt to climate change/ extremes and its impacts

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

Cropland

Cropland

  • Annual cropping
Main crops (cash and food crops):

paddy rice, vegetables

Waterways, waterbodies, wetlands

Waterways, waterbodies, wetlands

  • Ponds, dams
Main products/ services:

paddy rice, electric generation

3.3 Further information about land use

Water supply for the land on which the Technology is applied:
  • full irrigation
Number of growing seasons per year:
  • 1
Specify:

paddy rice is the main product

3.4 SLM group to which the Technology belongs

  • water harvesting
  • energy efficiency technologies
  • ecosystem-based disaster risk reduction

3.5 Spread of the Technology

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

There are 2 dykes on that stream

3.6 SLM measures comprising the Technology

structural measures

structural measures

  • S5: Dams, pans, ponds
  • S10: Energy saving measures

3.7 Main types of land degradation addressed by the Technology

chemical soil deterioration

chemical soil deterioration

  • Cn: fertility decline and reduced organic matter content (not caused by erosion)
water degradation

water degradation

  • Ha: aridification

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • reduce land degradation
Comments:

Sediments are leached from the mountain areas flow down to the stream ant therefrore the water contains organic matter that is beneficial for crops.

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

4.1 Technical drawing of the Technology

Author:

Khampheng Bounyavong

Date:

12/05/2017

4.2 Technical specifications/ explanations of technical drawing

The posts have length of about 1.5 m that are fixed into the ground water bottom at a deepness of around 50 cm.
There are two dike rows, each have width of 1 m and a length of approximattly 25 m (corresponding to the width of the stream)
The space between the two dikes is 1 m, the slope angle is 3-5 %
The beneficial area of these dikes is 10 ha of irrigated rice.
The construction material used consists of wooden post (diameters 10 cm and/a length 1.5 m), wood logs with of 20 cm diameter and length of 4-5 m, rattan used to thigten the wood logs with the post. Soil and small stone are put in the back of the wood logs and between the space of the two structures to limit water penetration. Then, also big stones are placed in front of the wood posts to stabilize the structure of the dikes.
After completion of the dike construction, a canal above the upper dike has to be digged to drain the accumulated water into the rice field.

4.3 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:
  • per Technology unit
Specify unit:

one dam

Specify volume, length, etc. (if relevant):

width 1m, height 1m, depth 50 cm in the ground, length 25 m cross the steam

other/ national currency (specify):

Kip

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

8000.0

Indicate average wage cost of hired labour per day:

50 000 kip

4.4 Establishment activities

Activity Type of measure Timing
1. Find dead wood logs Structural
2. Collect and prepare the rattan to tighten the wood Structural
3. Collect the stones and rocks Structural
4. Dyke installation Structural

4.5 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labour person 48.0 50000.0 2400000.0 100.0
Equipment Hummer piece 4.0 150000.0 600000.0 100.0
Equipment Axes piece 10.0 100000.0 1000000.0 100.0
Equipment Hoe piece 15.0 40000.0 600000.0 100.0
Equipment Shovel piece 10.0 50000.0 500000.0 100.0
Equipment Knife piece 10.0 25000.0 250000.0 100.0
Construction material Wood logs piece 10.0 50000.0 500000.0 100.0
Construction material Rattan line 200.0 20000.0 4000000.0 100.0
Construction material Stones m3 50.0 40000.0 2000000.0 100.0
Construction material Wood post piece 10.0 10000.0 100000.0 100.0
Total costs for establishment of the Technology 11950000.0

4.6 Maintenance/ recurrent activities

Activity Type of measure Timing/ frequency
1. Find the wood logs to repair the dikes Structural
2. Prepare the rattan to refix the logs with the posts Structural
3. Collect the stones to imrove the stabilize the dikes Structural
4. Repair the dike Structural
Comments:

Each year, people from the local community have to maintain and repair the dikes.

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

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labor person 48.0 50000.0 2400000.0 100.0
Construction material Wood logs piece 10.0 50000.0 500000.0 100.0
Construction material Rattan line 200.0 10000.0 2000000.0 100.0
Construction material Stones m3 10.0 50000.0 500000.0 100.0
Construction material Wood post piece 10.0 10000.0 100000.0 100.0
Total costs for maintenance of the Technology 5500000.0

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The labour for collecting the wood logs and the labour for the construction of the dike.

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
Specify average annual rainfall (if known), in mm:

870.00

Specifications/ comments on rainfall:

The driest month is January, with 14 mm of rainfall. In July, the precipitation reaches its peak. Heavy rain is between July-September. Total rain fall is about 3200 mm/year

Indicate the name of the reference meteorological station considered:

Natural resource office

Agro-climatic zone
  • humid

The warmest month of the year is May, with an average temperature of 22.3 °C. With16.6 °C on average, January is the coldest month of the year.

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.
Indicate if the Technology is specifically applied in:
  • convex situations

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):
  • coarse/ light (sandy)
Soil texture (> 20 cm below surface):
  • medium (loamy, silty)
Topsoil organic matter:
  • medium (1-3%)

5.4 Water availability and quality

Ground water table:

< 5 m

Availability of surface water:

medium

Water quality (untreated):

for agricultural use only (irrigation)

Is water salinity a problem?

Nee

Is flooding of the area occurring?

Nee

5.5 Biodiversity

Species diversity:
  • medium
Habitat diversity:
  • medium

5.6 Characteristics of land users applying the Technology

Sedentary or nomadic:
  • Sedentary
Market orientation of production system:
  • subsistence (self-supply)
Off-farm income:
  • less than 10% of all income
Relative level of wealth:
  • average
Individuals or groups:
  • groups/ community
Level of mechanization:
  • mechanized/ motorized
Gender:
  • women
  • men
Age of land users:
  • youth
  • middle-aged

5.7 Average area of land owned or leased by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • small-scale

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

Land ownership:
  • communal/ village
  • individual, not titled
Land use rights:
  • individual
Water use rights:
  • open access (unorganized)

5.9 Access to services and infrastructure

health:
  • poor
  • moderate
  • good
education:
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
markets:
  • poor
  • moderate
  • good
energy:
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

crop quality

decreased
increased
Quantity before SLM:

8 tons/ha

Quantity after SLM:

2 tons/ha

Comments/ specify:

Before gold mining company entered in the area the yield of rice raised to 8 tons/ha due to the aboundant irrigation water caused by the dike construction. But unfortunately actually (in 2017), due to gold excavating rice yield decreased to 2 tons/ha, only.

energy generation

decreased
increased
Comments/ specify:

Some households also install dynamo ( electric generator ) with production capacity of 1 Kwh.

Water availability and quality

irrigation water availability

decreased
increased
Comments/ specify:

Before, water for cultivation was insufficient especially during dry season as the stream water level was too low , after the weir construction the stream water level got high enough to fill the canal leading to the production area all-year round.

Socio-cultural impacts

conflict mitigation

worsened
improved
Comments/ specify:

Before dyke construction the villagers tried to bring water to their fields by small individual canals during dry season. This caused competition and conflicts on scares water scarcity. After the communal wire construction the conflicts situation have been been improved.

Ecological impacts

Water cycle/ runoff

water quantity

decreased
increased
Comments/ specify:

Without dikes, the stream water quantity was too low to produce enough yield mainly regardomg dry season cultivation. After weir construction the farmers let the water flow from the canal into the water reservoir which allows agricultural activities on a year-round basis.

Climate and disaster risk reduction

drought impacts

increased
decreased
Comments/ specify:

Even during dry season (and drought events) the farmers bring enough the water to the fields.

6.2 Off-site impacts the Technology has shown

reliable and stable stream flows in dry season

reduced
increased
Comments/ specify:

The weir stopped to some extent the natural water flow. This causes slower but still regular downstream water flow during dry season.

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change
Season Type of climatic change/ extreme How does the Technology cope with it?
annual temperature increase moderately
seasonal temperature dry season decrease well
seasonal rainfall wet/ rainy season increase moderately
other gradual climate change None increase well

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local hailstorm not well
Climatological disasters
How does the Technology cope with it?
extreme winter conditions not well
Hydrological disasters
How does the Technology cope with it?
flash flood moderately
Biological disasters
How does the Technology cope with it?
epidemic diseases moderately
insect/ worm infestation not well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
extended growing period not well

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:

slightly positive

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

slightly positive

Long-term returns:

slightly negative

6.5 Adoption of the Technology

  • 10-50%
Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 90-100%

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

Nee

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Inputs are economically beneficial.
Provides a reliable water supply for agricultural activities.
Electricity can be generated with a small dynamo.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Mitigates water use conflicts which could occur in the village.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view How can they be overcome?
It is only possible to construct a temporary weir due to the low quality of locally available materials
A great deal of time needs to be invested in annual maintenance work.

7. References and links

7.1 Methods/ sources of information

  • field visits, field surveys

1 time

  • interviews with land users

2 persons

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