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

Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)

Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)

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

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

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

Sim

1.4 Declaração de sustentabilidade da tecnologia descrita

A tecnologia descrita aqui é problemática em relação a degradação da terra de forma que não pode ser declarada uma tecnologia de gestão sustentável de terra?

Não

1.5 Referência ao(s) questionário(s) sobre abordagens GST (documentado(s) usando WOCAT)

Vu Gia Thu Bon River Basin Information Centre [Vietnã]

The VGTB River Basin Information Centre (RBIC) offers decision support tools for stakeholders and aims at providing comprehensive information and consulting services to the water and land users according to their demands.

• Compilador/a: Justyna Sycz
• 28/07/2015 00:00

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Return flow from paddy fields is strategically collected before being lost to rivers and is reused as an effective source of agricultural water.

2.2 Descrição detalhada da tecnologia

Descrição:

Return flow from paddy fields is defined as applied water that is not lost by evapotranspiration but returns to an aquifer or surface water body (Womach, 2005). The two types of return flow are surface and sub-surface. Surface return flow accounts for the major proportion. If surface return flow is strategically collected before entering rivers, it can be used as an ‘extra’ effective source of agricultural water supply (Phil King, 2008; Simons et al., 2015). Because paddies effectively purify water by absorbing nitrogen and phosphorus, this produces return flow of an acceptable quality for irrigation purposes. Return flow can be collected by drainage canals and stored in ponds and reservoirs, and then returned to pumps for reapplication. This technology offers one solution towards overcoming a deficit of irrigation water.

The goal of this technology is to store and reuse surface return flow from paddy farms to enhance irrigation efficiency. The purpose of constructing temporary barriers in drainage canals is to minimise water wastage and optimise the possibility of collecting and recycling surface return flow. Return flow from irrigation system is stored in surrounding ponds and reservoirs Return flow can only be used when it is captured in a storage structure or drain which has a hydraulic link to the irrigation source: thus an integrated framework for the reuse system consisting of both hydraulic, and management, links should be established. Within the scope of this study, the Water Management Unit (WMU) is understood as an integrated irrigation and drainage system consisting of four components: (i) the hydrological catchment which covers both non-irrigated and irrigated area; (ii) the source scheme generating return flow; (iii) the reuse scheme that is hydraulically connected with the source scheme; and (iv) a drainage system functioning as a harvesting as well as a supply structure.

Before implementing such a system it is recommended to analyse the correlation between irrigation efficiency and reuse of return flow, as well as developing a framework for managing and recycling return flow. Investigation aims at identifying the potential of return flow for irrigation; determining its quantity and quality; and developing an efficient and sustainable reuse framework. Water balance calculations, field measurements, water quality sampling and interviewing are all used for this purpose.

In the study area, long dry seasons cause severe water shortages and problems with saline intrusion. The study area is mainly covered by paddy, vegetables and other annual crops such as maize, sweet potatoes, peanuts and sugarcane. Paddy rice, which consumes a high proportion of the freshwater, is the dominant crop. Agricultural land in the downstream area is irrigated through gravity or pump irrigation systems. Here results indicate that the irrigation efficiency can be improved significantly: the irrigation efficiency of Tu Cau and Thanh Quyt irrigation schemes is projected to increase respectively by 1.8 and 1.4 times.

Reuse of return flow can be applied in all WMUs where the drainage canals are connected with storage tanks. Scientific and technical support tools are offered by the Vu Gia Thu Bon River Basin Information Centre. The centre was established in Danang providing a comprehensive information service to farmers and other water users – it includes capacity building and consulting services also.

2.3 Fotos da tecnologia

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

País:

Vietnã

Região/Estado/Província:

Quang Nam

Especificação adicional de localização:

Dien Ban

Map

×

2.6 Data da implementação

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

• menos de 10 anos atrás (recentemente)

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:

• atráves de inovação dos usuários da terra
• durante experiências/ pesquisa

3.1 Principal/principais finalidade(s) da tecnologia

• Melhora a produção
• Preserva ecossistema

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

Terra de cultivo

• Cultura anual
• Cultura perene (não lenhosa)
• Cultura de árvores e arbustos

Cultivo anual - Especificar culturas:

• cereais - milho
• cereais - arroz (zona húmida)
• culturas de raízes/tubos - batata doce, inhame, taro/cocoyam, outros

• vegetables

Cultivo perene (sem lã) - Especificar culturas:

• cana-de-açúcar

Cultivo de árvores e arbustos - Especificar culturas:

• frutos secos (castanhas do Brasil, pistache, nozes, amêndoas, etc.)

Número de estações de cultivo por ano:

• 2

Especifique:

Longest growing period in days: 130, Longest growing period from month to month: 20th December to 28th April; Second longest growing period in days: 110, Second longest growing period from month to month: 20th May to 06th September

Comentários:

Major land use problems (compiler’s opinion): The lowland part of Vu Gia Thu Bon is an intensive agricultural area. Rice cultivation, which consumes a high proportion of fresh water, accounts for 70% of total agricultural land (Ribbe et al., 2011). Since 2005, due to the impacts of droughts and saltwater intrusion, water for irrigation during the dry seasons has become an increasing problem in the lowland area of this basin. Simultaneously, the irrigation efficiency of this region is relative low. Various measures are applied to address water scarcity for irrigation. Reusing return flow is regarded as a potentially new measure to reduce the severity of the irrigation deficit in dry periods.
Major land use problems (land users’ perception): Based on the information provided by the Department of Natural Resources and Environment (DONRE) for Quang Nam Province, this basin now faces the problem of temporarily insufficient irrigation water. This situation is caused by droughts, insufficient reservoir capacity, salinity intrusion and ineffective irrigation management.

3.4 Abastecimento de água

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

• Irrigação completa

3.5 Grupo de GST ao qual pertence a tecnologia

• Coleta de água
• Gestão de água de superfície (nascente, rio, lagos, mar)

3.6 Medidas de GST contendo a tecnologia

Medidas estruturais

• S5: Represa, bacia, lago
• S6: Muros, barreiras, paliçadas, cercas

Medidas de gestão

• M2: Mudança de gestão/nível de intensidade
• M6: Gestão de resíduos (reciclagem, reuso ou redução)

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Degradação da água

• Hs: mudança na quantidade de água de superfície

Comentários:

Main causes of degradation: crop management (annual, perennial, tree/shrub) (Paddy rice requires huge amounts of water. Meanwhile, the coefficient of irrigation return flow from paddy field is also quite high.), industrial activities and mining (Hydropower construction reduces water availability for irrigation), over abstraction / excessive withdrawal of water (for irrigation, industry, etc.) (It causes water waste and reduces irrigation efficiency.), change of seasonal rainfall (It affects the paddy water balance and actual irrigation need.), droughts (It causes saltwater intrusion.)
Secondary causes of degradation: change in temperature (It relates to evapotranspiration.), inputs and infrastructure: (roads, markets, distribution of water points, other, …), governance / institutional

3.8 Redução, prevenção ou recuperação da degradação do solo

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

• Reduzir a degradação do solo

4.1 Desenho técnico da tecnologia

Especificações técnicas (relacionada ao desenho técnico):

Methods of recycling return flow from paddy fields: The surface return flow can be captured by drainage canals and stored in tanks: return water from these reservoirs is pumped back into irrigation canals.
In 2012, the first on-farm irrigation structure was initially implemented in the Tu Cau WMU in order to use return flow for irrigation purposes. The existing Sen Pond was enlarged and a temporary pumping station was installed to pump water into the irrigation canal system.
According to the pumping diary of Tu Cau station (in Winter-Spring crop 2013), there were totally 7 irrigation periods (8-11 days/period). Total input water (including effective rainfall) during the measuring period from 01 March to 10 April was about 28,000 m3. Meanwhile the total volume of return flow of the Tu Cau site was 16,176 m3. This amount of return flow has the potential to irrigate the agricultural area for about 16 days, equivalent to one and a half irrigation periods. The overall efficiency of the irrigation system will be significantly improved.
Location: Lowland area of VGTB Basin. Quang Nam Province
Date: January 2014

Technical knowledge required for field staff / advisors: high
Technical knowledge required for land users: low
Main technical functions: water harvesting / increase water supply

Dam/ pan/ pond
Depth of ditches/pits/dams (m): 2
Width of ditches/pits/dams (m): 194.9
Length of ditches/pits/dams (m): 399.4

Wall/ barrier
Height of bunds/banks/others (m): 0.5
Width of bunds/banks/others (m): 0.25
Length of bunds/banks/others (m): 1.26

Construction material (other): Stone, sandy bags and bamboo sticks
Specification of dams/ pans/ ponds: Capacity 116764.59m3
Catchment area: 77860 m²m2
Beneficial area: 30 ham2
Other type of management: Return flow is the part of drainage flow, it is necessary to enhance the institutional link to develop the reuse framework for the study area. Think about reforming IMC to IDMC with D is drainage.

Autor:

Trinh Quoc Viet

4.2 Informação geral em relação ao cálculo de entradas e custos

Outro/moeda nacional (especifique):

VND

Se for relevante, indique a taxa de câmbio do USD para moeda local (por exemplo, 1 USD = 79,9 Real): 1 USD =:

20828,0

4.3 Atividades de implantação

4.4 Custos e entradas necessárias para a implantação

Comentários:

Duration of establishment phase: 12 month(s)

4.5 Atividades recorrentes/manutenção

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

4.7 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

Prices of the material and equipment; the approval procedure and disbursement process of the project of “Dredging and expanding Sen Pond”; the compensation cost for the farmers; the cost of operating and maintaining temporary pump; the cost of reinforcing the drainage canals.

5.1 Clima

5.2 Topografia

5.3 Solos

5.4 Disponibilidade e qualidade de água

5.5 Biodiversidade

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 common / average land users
Population density: > 500 persons/km2
Annual population growth: 1% - 2%
1% of the land users are very rich and own 3% of the land.
2% of the land users are rich and own 7% of the land.
70% of the land users are average wealthy and own 60% of the land.
25% of the land users are poor and own 20% of the land.
2% of the land users are poor and own 10% of the land.
Off-farm income specification: There is a large industrial park located near the study site and a large part of the working population in the region is earning income by working in the factories.

5.7 Área média de terrenos utilizados pelos usuários de terrenos que aplicam a Tecnologia

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

Propriedade da terra:

• Estado

• farmer, individual

Direitos do uso da água:

• Acesso livre (não organizado)

• farmer, individual

5.9 Acesso a serviços e infraestrutura

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Disponibilidade e qualidade de água

Outros impactos socioeconômicos

Impactos socioculturais

Impactos ecológicos

Ciclo hídrico/escoamento

Solo

Outros impactos ecológicos

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

Extremos (desastres) relacionados ao clima

Desastres meteorológicos

Desastres climatológicos

Desastres hidrológicos

Outras consequências relacionadas ao clima

Outras consequências relacionadas ao clima

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)?

6.5 Adoção da tecnologia

De todos aqueles que adotaram a Tecnologia, quantos o fizeram espontaneamente, ou seja, sem receber nenhum incentivo/ pagamento material?

• 51-90%

Comentários:

By applying the technology, the potential reuse area of return flow is estimated about 33% of the study area (30.4ha of agricultural area is potentially irrigated by return flow). However, estimating the number of land user families that have implemented the technology is not the initial aim of the study. Therefore, it requires further detailed investigation and social survey as well.

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

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

7.1 Métodos/fontes de informação

7.2 Referências às publicações disponíveis

Título, autor, ano, ISBN:

Kim, H. K. et al. (2009) Estimation of irrigation return flow from paddy fields considering the soil moisture

Disponível de onde? Custos?

Agricultural Water Management, 96(5), 875–882.

Título, autor, ano, ISBN:

Phil King (2008) Return Flow Efficiency

Disponível de onde? Custos?

New Mexico Water Resources Research Institute

Título, autor, ano, ISBN:

Simons, G.W.H. et al. (2015) Water reuse in river basins with multiple users: A literature review

Disponível de onde? Custos?

Journal of Hydrology. 558–571

Título, autor, ano, ISBN:

Ribbe et al. (2011) Annex 2 to Milestone Report 2011 - Description of the Study Region including an updated stakeholder analysis,

Disponível de onde? Custos?

LUCCi project. ITT, Cologne University of Applied Sciences