Auto-Flowing Slurry Dam
(China)
Falling Water Dam
Description
Auto-flowing slurry dams is filled with dense slurry by water flow from upland to maintain eroded soil particles and runoff.
Falling water filled dams distribute widely in the middle reaches of the Yellow River, they are used to store water and wrap sediment which result from soil and water loss. On the Loess Plateau, in addition to the conditions of deep gully and steep slope, earth above the top of the dams can be used to build dams. First, soil is loosed with squirt guns, exploded or manually dug. Then, water is pumped up to the loose earth so as to rush the soil down along transporting ditch, turning the soil into dense mud to dam level surrounded by tamped banks. Under the press of gravity, the mud dehydrates, consolidates and becomes uniformly dense body of the dams. Compared with dams in other areas, the water power filled dams in the Yellow River basin are characterized by much denser mud, uniform particles and body texture, smaller transect of dams body, and wide applicability to soil materials such as sand soil, loess soil and weathering residue. The types of dams have widely applied to build moderate and small reservoirs and silt arresters in the middle reaches of the Yellow River, they play an important role in increase in agricultural production and reduction of sediment into the Yellow River.
Location
Location: Shanxi, Shaanxi, etc., China
No. of Technology sites analysed:
Geo-reference of selected sites
Spread of the Technology: evenly spread over an area (13062.0 km²)
In a permanently protected area?:
Date of implementation: more than 50 years ago (traditional)
Type of introduction
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through land users' innovation
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as part of a traditional system (> 50 years)
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during experiments/ research
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through projects/ external interventions
Picture of auto-flowing slurry dam in the Loess Plateau (LIU Baoyuan (Beijing China))
Classification of the Technology
Main purpose
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improve production
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reduce, prevent, restore land degradation
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conserve ecosystem
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protect a watershed/ downstream areas – in combination with other Technologies
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preserve/ improve biodiversity
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reduce risk of disasters
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adapt to climate change/ extremes and its impacts
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mitigate climate change and its impacts
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create beneficial economic impact
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create beneficial social impact
Land use
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Cropland
Number of growing seasons per year: 1
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Waterways, waterbodies, wetlands - Ponds, dams
Main products/ services: Auto-Flowing Slurry Dam
Water supply
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rainfed
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mixed rainfed-irrigated
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full irrigation
Purpose related to land degradation
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prevent land degradation
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reduce land degradation
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restore/ rehabilitate severely degraded land
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adapt to land degradation
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not applicable
Degradation addressed
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soil erosion by water - Wt: loss of topsoil/ surface erosion, Wg: gully erosion/ gullying
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soil erosion by wind - Et: loss of topsoil
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chemical soil deterioration - Cn: fertility decline and reduced organic matter content (not caused by erosion)
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water degradation - Ha: aridification
SLM group
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irrigation management (incl. water supply, drainage)
SLM measures
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structural measures - S5: Dams, pans, ponds
Technical drawing
Technical specifications
Establishment and maintenance: activities, inputs and costs
Calculation of inputs and costs
- Costs are calculated:
- Currency used for cost calculation: USD
- Exchange rate (to USD): 1 USD = n.a
- Average wage cost of hired labour per day: 3.00
Most important factors affecting the costs
Since the dam construction uses local materials, the most important factors affecting the cost are labor and equipment
Establishment activities
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preparing earth (Timing/ frequency: n/a)
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pumping water (Timing/ frequency: n/a)
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preparing base of the dam and its perimetric banks (Timing/ frequency: n/a)
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Flushing the prepared earth with water inside the banks of the dam (Timing/ frequency: 0.1~1)
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After dehydration and consolidation of the earth, repeat 3 and 4. (Timing/ frequency: n/a)
Maintenance activities
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Keeping the top of the dam level and free of crevice, water or rubbish (Timing/ frequency: timely)
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Keeping the top of the dam level and free of crevice, water or rubbish (Timing/ frequency: None)
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Keeping the slope of the dam compact and free of rill or weed. (Timing/ frequency: timely)
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Keeping the slope of the dam compact and free of rill or weed. (Timing/ frequency: None)
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Keeping the observation equipment work in order. (Timing/ frequency: timely)
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Keeping the observation equipment work in order. (Timing/ frequency: None)
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Preventing the base the dam from destroying by white ants and other animals. (Timing/ frequency: April to October/once a year)
Natural environment
Average annual rainfall
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< 250 mm
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251-500 mm
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501-750 mm
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751-1,000 mm
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1,001-1,500 mm
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1,501-2,000 mm
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2,001-3,000 mm
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3,001-4,000 mm
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> 4,000 mm
Agro-climatic zone
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humid
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sub-humid
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semi-arid
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arid
Specifications on climate
n.a.
Slope
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flat (0-2%)
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gentle (3-5%)
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moderate (6-10%)
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rolling (11-15%)
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hilly (16-30%)
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steep (31-60%)
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very steep (>60%)
Landforms
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plateau/plains
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ridges
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mountain slopes
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hill slopes
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footslopes
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valley floors
Altitude
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0-100 m a.s.l.
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101-500 m a.s.l.
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501-1,000 m a.s.l.
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1,001-1,500 m a.s.l.
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1,501-2,000 m a.s.l.
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2,001-2,500 m a.s.l.
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2,501-3,000 m a.s.l.
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3,001-4,000 m a.s.l.
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> 4,000 m a.s.l.
Technology is applied in
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convex situations
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concave situations
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not relevant
Soil depth
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very shallow (0-20 cm)
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shallow (21-50 cm)
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moderately deep (51-80 cm)
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deep (81-120 cm)
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very deep (> 120 cm)
Soil texture (topsoil)
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coarse/ light (sandy)
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medium (loamy, silty)
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fine/ heavy (clay)
Soil texture (> 20 cm below surface)
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coarse/ light (sandy)
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medium (loamy, silty)
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fine/ heavy (clay)
Topsoil organic matter content
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high (>3%)
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medium (1-3%)
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low (<1%)
Groundwater table
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on surface
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< 5 m
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5-50 m
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> 50 m
Availability of surface water
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excess
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good
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medium
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poor/ none
Water quality (untreated)
-
good drinking water
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poor drinking water (treatment required)
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for agricultural use only (irrigation)
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unusable
Is salinity a problem?
Occurrence of flooding
Characteristics of land users applying the Technology
Market orientation
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subsistence (self-supply)
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mixed (subsistence/ commercial)
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commercial/ market
Off-farm income
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less than 10% of all income
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10-50% of all income
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> 50% of all income
Relative level of wealth
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very poor
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poor
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average
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rich
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very rich
Level of mechanization
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manual work
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animal traction
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mechanized/ motorized
Sedentary or nomadic
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Sedentary
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Semi-nomadic
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Nomadic
Individuals or groups
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individual/ household
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groups/ community
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cooperative
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employee (company, government)
Age
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children
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youth
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middle-aged
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elderly
Area used per household
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< 0.5 ha
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0.5-1 ha
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1-2 ha
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2-5 ha
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5-15 ha
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15-50 ha
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50-100 ha
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100-500 ha
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500-1,000 ha
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1,000-10,000 ha
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> 10,000 ha
Scale
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small-scale
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medium-scale
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large-scale
Land ownership
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state
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company
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communal/ village
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group
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individual, not titled
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individual, titled
Land use rights
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open access (unorganized)
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communal (organized)
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leased
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individual
Water use rights
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open access (unorganized)
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communal (organized)
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leased
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individual
Access to services and infrastructure
Impacts
Ecological impacts
surface runoff
Quantity before SLM: 43
Quantity after SLM: 35
soil loss
Quantity before SLM: 80
Quantity after SLM: 21
Cost-benefit analysis
Benefits compared with establishment costs
Short-term returns
very negative
very positive
Long-term returns
very negative
very positive
Benefits compared with maintenance costs
Short-term returns
very negative
very positive
Long-term returns
very negative
very positive
Adoption and adaptation
Percentage of land users in the area who have adopted the Technology
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single cases/ experimental
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1-10%
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11-50%
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> 50%
Of all those who have adopted the Technology, how many have done so without receiving material incentives?
-
0-10%
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11-50%
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51-90%
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91-100%
Number of households and/ or area covered
80'000 households (3 percent of the area)
Has the Technology been modified recently to adapt to changing conditions?
To which changing conditions?
-
climatic change/ extremes
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changing markets
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labour availability (e.g. due to migration)
Conclusions and lessons learnt
Strengths: land user's view
Strengths: compiler’s or other key resource person’s view
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
References
Reviewer
-
David Streiff
-
Alexandra Gavilano
Date of documentation: Dec. 6, 2010
Last update: March 14, 2019
Resource persons
-
Yan ZHANG - SLM specialist
Full description in the WOCAT database
Documentation was faciliated by
Institution
- Department of Resources and Environmental Science, Beijing Normal University (Department of Resources and Environmental Science, Beijing Normal University) - China
Project
Key references
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Special Planning Of Soil And Water Conservation in Xinzhou Region , Shanxi Province. 1986-1990.: Library of the Resource and Environmental Department, Beijing Normal University.
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How to design the dry masonry dam in the Hanjiachuan watershed. Tianyuzhu, Wangzuliang. Beijing. Water conservation in Beijing. 2000.: Library of the Resource and Environmental Department, Beijing Normal University.
