1.2 Detalhes do contato das pessoas capacitadas e instituições envolvidas na avaliação e documentação da tecnologia

Nome da(s) instituição(ões) que facilitou(ram) a documentação/ avaliação da Tecnologia (se relevante)

Northwest A&F University (NWAFU) - China

1.3 Condições em relação ao uso da informação documentada através de WOCAT

Quando os dados foram compilados (no campo)?

20/12/2008

O/a compilador/a e a(s) pessoa(s) capacitada(s) aceitam as condições relativas ao uso de dados documentados através da WOCAT:

Sim

1.5 Referência ao(s) questionário(s) sobre as abordagens da GST

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Check dam for land is a structural SLM practice that is constructed in the valley of a watershed in order to slow down the runoff and increase sedimentation. After this, the land quality of the controlling area will increase because soil and water conditions in this place are imporved.

2.2 Descrição detalhada da tecnologia

Descrição:

The check dam is a small dam designed to reduce flow velocity, control soil erosion, and allow to settle on the bed of the valley. The whole system includes main body of dam, spillway, overflow and supporting measures. The check dam for land is a small dam mainly for land after it is filled up by the sediment from upstream area, from several years to 20 years in common, it could be flat land in the valley, not mainly for water collection (different from reservior).

Purpose of the Technology: Check dams in the Loess Plateau are very common. There are many advantages. The check dam could not only reduce the erosion of the gullies, furthermore it retain the sediment in the flow and this decreases the sediment of the Yellow River. The check dam is good quality land for the soils because of the sedimentation of organic matter and other nutrients from topsoil . In this region soils are deep and very fertile because most soil is from the top soil upstream. The soil moisture of check dam is also much better than in any other places in the watershed because the flood should go away from its surface and the water inflitration is great in raining seasons.

Establishment / maintenance activities and inputs: The establishment needs enough money because it has to be safe enough, and the maintenance cost is not so high. The catchment with great soil erosion is better when we considered the formation time of land.

Natural / human environment: The controlling area of check dam for land varies greatly from 30 square km or more. Since the "Grain for Green" Project of China in 1999, the soil erosion on the slope decreased. The time from reservoir to land need more time because there is less and less sediment from upstream and the sedimentation changed slowly.

2.3 Fotos da tecnologia

2.5 País/região/locais onde a tecnologia foi aplicada e que estão cobertos nesta avaliação

2.6 Data da implementação

Caso o ano exato seja desconhecido, indique a data aproximada:

• 10-50 anos atrás

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:

• durante experiências/ pesquisa

Comentários (tipos de projeto, etc.):

It is an old methodology in the Loess Plateau. Since 2003, the check dam had been determined as "Highlight Project " of the Ministry of Water Resources in order to expand in the whole area of the Yellow River Basin.

3.1 Principal/principais finalidade(s) da tecnologia

• Reduz, previne, recupera a degradação do solo

3.2 Tipo(s) atualizado(s) de uso da terra onde a tecnologia foi aplicada

Comentários:

Major land use problems (compiler’s opinion): Normally, the bed of valley is V-shaped and is covered by grass and trees. For the seasonal torrent or flash, it is very difficult to plant crops. The gully also cuts down by runoff and extends because of erosion's gravity .

Major land use problems (land users’ perception): It can not be used as agricultural purpose, especially to get more food.

Future (final) land use (after implementation of SLM Technology): Cropland: Ca: Annual cropping

Livestock is grazing on crop residues

Caso o uso da terra tenha mudado devido a implementação da tecnologia, indique seu uso anterior à implementação da tecnologia:

Mixed: Ms: Silvo-pastoralism

3.3 Mais informações sobre o uso da terra

Abastecimento de água para a terra na qual a tecnologia é aplicada:

• Precipitação natural

Especifique:

Longest growing period in days: 300Longest growing period from month to month: March to NovemberSecond longest growing period in days: 200Second longest growing period from month to month: April to October

3.4 Grupo de GST ao qual pertence a tecnologia

• Medidas de curva de nível
• Gestão de água de superfície (nascente, rio, lagos, mar)

3.5 Difusão da tecnologia

Comentários:

Total area covered by the SLM Technology is 19.4 m2.

The total area with different measures is almost 2000 km2 . Yanhe River is a first class branch of Yellow River, China. The average channel slope is 3.26‰, and the area of whole basin is 7,687 km2. It is situated in the semi-arid North Temperate Zone with an average annual precipitation varying from 500 to 550 mm, and an average annual air temperature ranging from 8.5 to 11.4℃. It is in hilly gully area of the Loess Plateau covered by loess. The landform is broken seriously. The gully density (the length of channel in one km2) is amount to 2.1 to 4.6 km•km-2. The soil loss is severe all along.
The Ganguyi Hydrology Station (109°48′E, 36°42′N) located in the Ganguyi Town, Baota Country, Yan’an City, Shaanxi Province. The area up Ganguyi Hydrology Station is 5,891 km2, including of Jingbian County(256km2), Zhidan County(708km2), Ansai County(2,699km2) and Baota County(2,228km2). The average annual runoff is 0.22 billion m3, and the runoff modulus accounting for 4,776.36 m3•km-2•yr-1. The average annual sediment flow is 4.776 million tons, and the sediment flow modulus accounting for 8,100 t•km-2•yr-1. The coarse sediment (sediment particle diameter not less than 0.05 mm) flow modulus is 2,430 t•km-2•yr-1 on the Ganguyi Hydrology Station.

3.6 Medidas de GST contendo a tecnologia

Comentários:

Main measures: structural measures

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Comentários:

Main type of degradation addressed: Wg: gully erosion / gullying

Secondary types of degradation addressed: Wo: offsite degradation effects

Secondary causes of degradation: Heavy / extreme rainfall (intensity/amounts) (It is the reason of erosion that influence the valley.)

3.8 Redução, prevenção ou recuperação da degradação do solo

Especifique o objetivo da tecnologia em relação a degradação da terra:

• Prevenir degradação do solo
• Reduzir a degradação do solo

Comentários:

Main goals: prevention of land degradation

Secondary goals: mitigation / reduction of land degradation

4.1 Desenho técnico da tecnologia

4.2 Especificações técnicas/ explicações do desenho técnico

The check dam land.

Location: Mazhuang Watershed. Baota County, Yan'an City, Shaanxi China

Date: 2008-10-20

Technical knowledge required for field staff / advisors: high (The design and construction need professional knowledge.)

Technical knowledge required for land users: low (it is easy to use, like alluvial land or wide terrace.)

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

Spillway
Vertical interval between structures (m): 3
Spacing between structures (m): 6
Height of bunds/banks/others (m): 4
Width of bunds/banks/others (m): 6
Length of bunds/banks/others (m): 100

Dam/ pan/ pond
Vertical interval between structures (m): 10
Spacing between structures (m): 100
Depth of ditches/pits/dams (m): 10
Width of ditches/pits/dams (m): 50-100
Length of ditches/pits/dams (m): 300-1000

Construction material (earth): The earth-bank dam is built in Yanhe River Basin.

Construction material (stone): to build the spillways

Slope (which determines the spacing indicated above): 2-5%

If the original slope has changed as a result of the Technology, the slope today is: 2%

Lateral gradient along the structure: 2%

Specification of dams/ pans/ ponds: Capacity 180000m3

Catchment area: 58.3km2m2

Slope of dam wall inside: 30%;
Slope of dam wall outside: 60%

Dimensions of spillways: 3m

Vegetation is used for stabilisation of structures.

4.3 Informação geral em relação ao cálculo de entradas e custos

Especifique a moeda utilizada para os cálculos de custo:

• Dólares norte-americanos

Indique a taxa cambial do dólar norte americano para a moeda local (se relevante): 1 USD =:

-2,17

4.4 Atividades de implantação

	Atividade	Tipo de medida	Periodicidade
1.	Field survey and location selection	Estrutural	Before design
2.	Design	Estrutural	before construction
3.	Build the dam wall	Estrutural
4.	Check and accept	Estrutural	After the construction

4.5 Custos e entradas necessárias para a implantação

	Especifique a entrada	Unidade	Quantidade	Custos por unidade	Custos totais por entrada	% dos custos arcados pelos usuários da terra
Mão-de-obra	Building the wall/ field survey and planning	Person/day	180,0	8,8	1584,0	90,0
Mão-de-obra	Building the wall/ field survey	Machine/hrs	75,0	43,8	3285,0
Material de construção	Stone	m^3	40,0	26,35	1054,0
Custos totais para a implantação da tecnologia					5923,0

Comentários:

Duration of establishment phase: 1 month(s)

4.6 Atividades recorrentes/manutenção

	Atividade	Tipo de medida	Periodicidade/frequência
1.	check the dam wall	Estrutural	annually

4.7 Custos e entradas necessárias pata a manutenção/atividades recorrentes (por ano)

	Especifique a entrada	Unidade	Quantidade	Custos por unidade	Custos totais por entrada	% dos custos arcados pelos usuários da terra
Mão-de-obra	check annualy the dam wall	Person/day	15,0	8,8	132,0
Custos totais para a manutenção da tecnologia					132,0

Comentários:

Machinery/ tools: crawler type bulldozer, giant jet, tractor, traditional tools, ruler,

The grass on both sides of check wall is natural grass.

4.8 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

The wide of dam wall affects the cost greatly, the wider, more expensive.The labour cost and the distance of rock quarry are also important.

5.1 Clima

5.2 Topografia

Indique se a tecnologia é aplicada especificamente em:

• Posições côncavas

Comentários e outras especificações sobre a topografia:

Altitudinal zone: All check dam and check dam liand here is in such altitudinal zonation.

Slopes on average: Based on 1:100 thousand scale landform map

5.3 Solos

Caso disponível anexe a descrição completa do solo ou especifique as informações disponíveis, p. ex. tipo de solo, PH/acidez do solo, nitrogênio, capacidade de troca catiônica, salinidade, etc.

Soil depth on average: The depth of Loess varies from nearly 30 m to more than 100 m in Yanhe River Basin. The depth of soil is less than this but it could be nearly 10 meters in commom.

Soil texture: There are more than 50% soil particle which are fine sand with size between 0.05 and 0.1 mm

Soil fertility very low: Lack of N, P and SOM

Topsoil organic matter: <0.5%

Soil drainage / infiltration good: The inflitration in Loess is very fast, but it prones to sealing when flashing

Soil water storage capacity low: Evaporation and drainage are easy

5.4 Disponibilidade e qualidade de água

Comentários e outras especificações sobre a qualidade e a quantidade da água:

Availability of surface water also poor/ none and: Nearly all the branches of Yanhe are seasonal rivers

Availability of surface water medium: It is very stable in this region

Water quality (untreated): Good quality for there are few pollution sources

5.5 Biodiversidade

Comentários e outras especificações sobre biodiversidade:

It is very stable in this region

5.6 Características dos usuários da terra que utilizam a tecnologia

Indique outras características relevantes dos usuários da terra:

Land users applying the Technology are mainly Leaders / privileged

Difference in the involvement of women and men: No clear difference

Population density: 50-100 persons/km2

Annual population growth: < 0.5%

(The Check dam for land are build together in some villages for all the people funded by national sub).

Level of mechanization also manual work: The harvesting and other management are by hand

Level of mechanization animal traction: Tillage with animal power mostly

Level of mechanization mechanized/motorized: Tillage with machine in large area check-dam land.

Market orientation of production system mixed: Some production for themselves, but most of production is exchanged on the market.

5.7 Média da área de terra própria ou arrendada por usuários da terra que utilizam a tecnologia

5.8 Propriedade de terra, direitos de uso da terra e de uso da água

Propriedade da terra:

• Estado
• Comunitário/rural

Direitos do uso da terra:

• Indivíduo

Direitos do uso da água:

• Acesso livre (não organizado)

Comentários:

Like other rural areas in China

5.9 Acesso a serviços e infraestrutura

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Impactos socioculturais

Impactos ecológicos

Ciclo hídrico/escoamento

Solo

Outros impactos ecológicos

6.2 Impactos externos mostrados pela tecnologia

6.3 Exposição e sensibilidade da tecnologia às mudanças climáticas graduais e extremos/desastres relacionados ao clima (conforme o ponto de vista dos usuários da terra)

Mudança climática gradual

Mudança climática gradual

	Estação do ano	Tipo de mudança climática/extremo	Como a tecnologia lida com isso?
Temperatura anual		aumento	bem

Extremos (desastres) relacionados ao clima

Desastres meteorológicos

	Como a tecnologia lida com isso?
Temporal local	bem
Tempestade de vento local	bem

Desastres climatológicos

	Como a tecnologia lida com isso?
Seca	bem

Desastres hidrológicos

	Como a tecnologia lida com isso?
Inundação geral (rio)	bem

Outras consequências relacionadas ao clima

Outras consequências relacionadas ao clima

	Como a tecnologia lida com isso?
Período de crescimento reduzido	não conhecido

Comentários:

The better condition of soil and water of check dam land improves the capacity of land tp cope with the changing climate.

6.4 Análise do custo-benefício

Como os benefícios se comparam aos custos de implantação (do ponto de vista dos usuários da terra)?

Como os benefícios se comparam aos custos recorrentes/de manutenção(do ponto de vista dos usuários da terra)?

Comentários:

In the first stage, there is no economic output but the check dam is going to fill up with sediments. Afterwards the check dam forms land and with it benefit which would keep up a long time.

6.5 Adoção da tecnologia

• 10-50%

Se disponível, determine a quantidade (número de unidades familiares e/ou área abordada):

675 households in an area of 19.4 km^2 (11 percent of the area)

Entre todos aqueles que adotaram a tecnologia, quantos adotaram espontaneamente, ou seja, sem receber nenhum incentivo material/pagamentos?

• 0-10%

Comentários:

100% of land user families have adopted the Technology with external material support

675 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: All the lands (cropland on the slope or check dam land and forest et al, ) are shared evenly by people. Of course, the work like to build check dam should be finished by all the families.

Comments on spontaneous adoption: No single farmer or family can finish this work because the land right and great investment.

There is a strong trend towards spontaneous adoption of the Technology

Comments on adoption trend: More and more local farmers want to get more check dam land for its long-term benefits.

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

Pontos fortes/vantagens/oportunidades na visão do usuário da terra
The yield of check dam land is much higher than that on the slope land. How can they be sustained / enhanced? Ask the local people to do more work without payment because they would get more benefits from this land as such.
The yield is stable because the soil moisture is good even in dry year How can they be sustained / enhanced? Use the land efficient and mainten it.

Pontos fortes/vantagens/oportunidades na visão do/a compilador/a ou de outra pessoa capacitada
It could reduce the soil erosion originated from the gully. How can they be sustained / enhanced? The local people know this benefit that make them try to find chance to build check dam.
The dam can retain the flow and sediment and reduces the sediment delivery of the downstream. How can they be sustained / enhanced? Ask the people or government of the lower reaches to combat soil erosion through the building of check dams.
The check dam land is fertile and productive How can they be sustained / enhanced? When we make the plan or design the construction, we should better take this into account.
Land is fertile and productive How can they be sustained / enhanced? Improve the awareness of local people to use this technology.
The ceck dam can be used as rural road. How can they be sustained / enhanced? When we make the plan or design the construction, we should better take this into account.

6.8 Pontos fracos, desvantagens/riscos da tecnologia e formas de superá-los

Pontos fracos/desvantagens/riscos na visão do usuário da terra	Como eles podem ser superados?
It is too expensive to build the check dam.	Ask the government or other organization and person to invest in check dams.The local people can work together without payment.

Pontos fracos/vantagens/riscos na visão do/a compilador/a ou de outra pessoa capacitada	Como eles podem ser superados?
The land in a check dam with less and less soil erosion on the slope, needs longer time to form	It is difficult to overcome this because the control of erosion on slope has higher priority. We can find how to use the water or the temporary wetland.
The input of check dam is quite high.	Ask the government or other organization and person to invest in check dams. The local people can work together without payment.

7.2 Referências às publicações disponíveis

Título, autor, ano, ISBN:

Soil and water conservation records of Shaanxi Province. 2000. Shaanxi People's Press, Xi'an City, China

Disponível de onde? Custos?

Library of ISWC, CAS