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

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

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:

Yes

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?

No

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

Specify the spread of the Technology:

• applied at specific points/ concentrated on a small area

Comments:

There are 2 dykes on that stream

Map

×

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)

3.1 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

• Annual cropping

Annual cropping - Specify crops:

• cereals - rice (wetland)
• vegetables - other

Number of growing seasons per year:

• 1

Specify:

paddy rice is the main product

Waterways, waterbodies, wetlands

• Ponds, dams

Main products/ services:

paddy rice, electric generation

3.4 Water supply

Water supply for the land on which the Technology is applied:

• full irrigation

3.5 SLM group to which the Technology belongs

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

3.6 SLM measures comprising the Technology

structural measures

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

3.7 Main types of land degradation addressed by the Technology

chemical soil deterioration

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

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.

4.1 Technical drawing of the Technology

Technical specifications (related to 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.

Author:

Khampheng Bounyavong

Date:

12/05/2017

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology unit

other/ national currency (specify):

Kip

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

8000.0

4.3 Establishment activities

4.4 Costs and inputs needed for establishment

4.5 Maintenance/ recurrent activities

Comments:

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

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

4.7 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.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• convex situations

5.3 Soils

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

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

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Climate and disaster risk reduction

6.2 Off-site impacts the Technology has shown

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

Climate-related extremes (disasters)

Meteorological disasters

Climatological disasters

Hydrological disasters

Biological disasters

Other climate-related consequences

Other climate-related consequences

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• 11-50%

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 91-100%

6.6 Adaptation

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

No

6.7 Strengths/ advantages/ opportunities of the Technology

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

7.1 Methods/ sources of information