Check Dam [China]
- Creation:
- Update:
- Compiler: Haiyan WEI
- Editor: –
- Reviewers: David Streiff, Alexandra Gavilano
Lan Sha Ba
technologies_1365 - China
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Expand all Collapse all1. General information
1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology
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
1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)
Check Dam [China]
Check dam is a kind of sediment storage dam of 5m below and is built in channels to control the down cutting of channel bed.
- Compiler: Haiyan WEI
2. Description of the SLM Technology
2.1 Short description of the Technology
Definition of the Technology:
Check dam refers to dam that constructed in the gullies or river ways and the height of the dam is often lower than 5m.
2.2 Detailed description of the Technology
Description:
Check dams are built in the gully systems to harvest water and sediment. Usually many check dams are built in a gully or waterway to control the gully erosion. Check dams can be classified into "masonry dam", "check dam of earth", "check dam with willow" according to materials. Some strong masonry can last more than 10 years. As willow pegs in the "check dam with willow" can grow into timber after years.
Maintenance work should be done before rainy seasons every year so as to prevent the dam from destruction.
Following are the building procedures:
Masonry dam & check dam using earth:
1. Preparation---Removing grass, roots and surface soil; Digging a channel along an axis of a check dam in order to combine the dam and the bed firmly.
2. Construction---If a dam is planned to be made of earth, do scarification first, then adding earth (about 0.3m thick) and ramming it into 0.2m layer by layer. Building the dam with stones and/or rocks.
3. Base---If a bed of a gully consists of earth or sand, "base" should be built at the downstream feet of the dam. Length of the base should be twice as that of the dam and thickness should be 50-70cm.
4. Building a spillway at the top of the dam.
Check dam with willow:
1. Removing grass, roots and surface soil.
2. Cutting branches from willow; chopping the branches into pegs with the thick ends wedge.
3. Inserting the pegs into the ground.
4. Entwining wattles from willows around the pegs compactly.
5. Filling the space between two rows of pegs with stones, bricks, treetops etc. Making the stuff surface 10cm lower than the pegtop.
6. Combining the dam into a whole with iron chains.
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:
China
Region/ State/ Province:
Shanxi, Beijing
Specify the spread of the Technology:
- evenly spread over an area
If the Technology is evenly spread over an area, specify area covered (in km2):
145.0
If precise area is not known, indicate approximate area covered:
- 100-1,000 km2
Comments:
Total area covered by the SLM Technology is 145 km2.
As a traditional SWC technology, check dams have been used widely in China.
Map
×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.):
Experiences from the local people's many SWC practice.
3. Classification of the SLM Technology
3.1 Main purpose(s) of the Technology
- reduce, prevent, restore land degradation
3.2 Current land use type(s) where the Technology is applied
Land use mixed within the same land unit:
Yes
Specify mixed land use (crops/ grazing/ trees):
- Agro-pastoralism (incl. integrated crop-livestock)
Cropland
- Annual cropping
Annual cropping - Specify crops:
- cereals - maize
- cereals - wheat (winter)
Number of growing seasons per year:
- 1
Specify:
Longest growing period in days: 180Longest growing period from month to month: Apr - Sep
Grazing land
Waterways, waterbodies, wetlands
- Ponds, dams
Main products/ services:
Check Dam
Comments:
Major land use problems (compiler’s opinion): Serious gully erosion by water.
Major land use problems (land users’ perception): Gullies were widened and deepened greatly in the rainy season and crop land area is decreasing above the gully edges.
Constraints of urban land use
3.4 Water supply
Water supply for the land on which the Technology is applied:
- mixed rainfed-irrigated
3.5 SLM group to which the Technology belongs
- surface water management (spring, river, lakes, sea)
- reduce loss of cropland
3.6 SLM measures comprising the Technology
vegetative measures
- V1: Tree and shrub cover
structural measures
- S5: Dams, pans, ponds
Comments:
Main measures: structural measures
3.7 Main types of land degradation addressed by the Technology
soil erosion by water
- Wg: gully erosion/ gullying
Comments:
Main type of degradation addressed: Wg: gully erosion / gullying
Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), poverty / wealth (Lack of captial)
Secondary causes of degradation: other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify, education, access to knowledge and support services (Lack of knowledge), Lack of enforcement of legislat./authority
3.8 Prevention, reduction, or restoration of land degradation
Specify the goal of the Technology with regard to land degradation:
- reduce land degradation
4. Technical specifications, implementation activities, inputs, and costs
4.1 Technical drawing of the Technology
Technical specifications (related to technical drawing):
Description of Building Check Dam Procedures
Location: the Loess Plateau. Shanxi, Beijing
Date: 2000
Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: moderate
Main technical functions: control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, water harvesting / increase water supply, water spreading
Secondary technical functions: increase / maintain water stored in soil
Construction material (earth): Loessial earth
Construction material (stone): if available
Construction material (wood): willow pegs
Slope (which determines the spacing indicated above): 30%
If the original slope has changed as a result of the Technology, the slope today is: 16%
Lateral gradient along the structure: 90%
For water harvesting: the ratio between the area where the harvested water is applied and the total area from which water is collected is: 1:30
Author:
LIU Baoyuan, Beijing China
4.2 General information regarding the calculation of inputs and costs
other/ national currency (specify):
RMB Yuan
If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:
8.27
Indicate average wage cost of hired labour per day:
2.00
4.3 Establishment activities
Activity | Timing (season) | |
---|---|---|
1. | Preparation | |
2. | Construction | Before rainy season |
4.4 Costs and inputs needed for establishment
Comments:
Duration of establishment phase: 120 month(s)
4.5 Maintenance/ recurrent activities
Activity | Timing/ frequency | |
---|---|---|
1. | reparing after rainstorm. |
4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)
Comments:
Length, width and height of check dams.
4.7 Most important factors affecting the costs
Describe the most determinate factors affecting the costs:
Sizes and materials of the check dams.
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:
580.00
Agro-climatic zone
- semi-arid
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:
- concave situations
Comments and further specifications on topography:
Slopes on average also gentle, moderate and rolling
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)
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 fertility: low
Soil drainage / infiltration: medium
Soil water storage capacity: low
5.6 Characteristics of land users applying the Technology
Off-farm income:
- 10-50% of all income
Relative level of wealth:
- average
Level of mechanization:
- animal traction
- mechanized/ motorized
Indicate other relevant characteristics of the land users:
Population density: 100-200 persons/km2
Annual population growth: < 0.5%
30% of the land users are average wealthy and own 20% of the land (No difference).
Off-farm income specification: The land users who made the check dams can own more "deposited land". Generally these deposited land is fertile and produces high yield.
Level of mechanization: animal traction: on steep slope
Level of mechanization: mechanized/motorized: plateau or gully flat.
5.8 Land ownership, land use rights, and water use rights
Land ownership:
- state
Land use rights:
- communal (organized)
6. Impacts and concluding statements
6.1 On-site impacts the Technology has shown
Ecological impacts
Water cycle/ runoff
surface runoff
Quantity before SLM:
48
Quantity after SLM:
30
Soil
soil loss
Quantity before SLM:
180
Quantity after SLM:
110
6.4 Cost-benefit analysis
How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:
positive
Long-term returns:
very positive
How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:
positive
Long-term returns:
very positive
6.5 Adoption of the Technology
- > 50%
If available, quantify (no. of households and/ or area covered):
180 household are using the technology and represent 65 percent of the poeple living in the stated area
Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
- 11-50%
Comments:
55% of land user families have adopted the Technology with external material support
150 land user families have adopted the Technology with external material support
Comments on acceptance with external material support: estimates
10% of land user families have adopted the Technology without any external material support
30 land user families have adopted the Technology without any external material support
Comments on spontaneous adoption: estimates
There is a little trend towards spontaneous adoption of the Technology
Comments on adoption trend: In the past (planning economy)SWC activities are administrative action to call local land users to carry out, but nowadays in the market economic conditions, if no or little benefits obtained, land users would not like to do any more.
7. References and links
7.1 Methods/ sources of information
7.2 References to available publications
Title, author, year, ISBN:
How to design the dry masonry dam in the Hanjiachuan watershed. Tianyuzhu, Wangzuliang. Beijing. Water conservation in Beijing.. 2000.3.
Available from where? Costs?
Library of the Resource and Environmental Department of the Beijing Normal Univ.
Title, author, year, ISBN:
Consideration about the check dam design and application. Liu shunzong. Soil and water conservation in China.. 1990.6.
Available from where? Costs?
Library of the Resource and Environmental Department of the Beijing Normal Univ.
Title, author, year, ISBN:
Special Planning of Soil and Water Conservation in Xinzhou Region, Shanxi Province. 1986-2000.
Available from where? Costs?
Library of the Resource and Environmental Department of the Beijing Normal Univ.
Title, author, year, ISBN:
The application of the Check dam with willow in controlling gully erosion.Tu xingwen. Soil and water conservation in China.. 1986.
Available from where? Costs?
Library of the Resource and Environmental Department of the Beijing Normal Univ.
Links and modules
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Check Dam [China]
Check dam is a kind of sediment storage dam of 5m below and is built in channels to control the down cutting of channel bed.
- Compiler: Haiyan WEI
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