Tecnologias

Sunken streambed structure [Índia]

DOH

technologies_1471 - Índia

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1. Informação geral

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

Pessoa(s) capacitada(s)

Especialista em GST:
Especialista em GST:

Agrawal VK

Comprehensive Watershed Development Project

Índia

Especialista em GST:
Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)
Book project: Water Harvesting – Guidelines to Good Practice (Water Harvesting)
Nome do projeto que facilitou a documentação/avaliação da Tecnologia (se relevante)
Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)

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

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

Sim

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

Comprehensive watershed development
approaches

Comprehensive watershed development [Índia]

Participatory approach that includes a package of measures leading to empowerment of communities to implement and sustain watershed development.

  • Compilador/a: David Gandhi

2. Descrição da tecnologia de GST

2.1 Descrição curta da tecnologia

Definição da tecnologia:

Excavations in streambeds to provide temporary storage of runoff, increasing water yields from shallow wells for supplementary irrigation.

2.2 Descrição detalhada da tecnologia

Descrição:

Dohs are rectangular excavations in seasonal streambeds, which are intended to capture and hold runoff to enhance groundwater recharge, thus increasing water for irrigation from nearby shallow wells. They also collect and impound subsurface flow. Dohs are built in semi-arid areas where rainfall is low and seasonal. The dimension of a typical doh is 1.0-1.5 m deep with variable length (up to 40 m) and width (up to 10 m) depending on streambed section, with an average capacity of 400 m3.

Purpose of the Technology: The excavated material is deposited along the stream banks as a barrier against siltation from surrounding areas. The slopes of the excavation are gentle (an upstream slope of 1:6 or 17% and a downstream slope of 1:8 or 12%) so that water flows into it, and excess water out again, carrying silt rather than depositing it. The sides however are steep, to increase capacity - and would benefit from stone pitching to stabilise them. A silt trap comprising a line of loose boulders is constructed upstream across the streambed. Dohs are generally built in sequence. They may be as close as a few metres apart. Bends in the stream are avoided as these are susceptible to bank erosion.

Establishment / maintenance activities and inputs: The technology is used in conjunction with shallow wells (odees), which enable farmers to harvest the increased groundwater for supplementary irrigation of annual crops- including vegetables such as chilli peppers. Water is pumped out of the wells. In the case study village, Mohanpada, each doh basically supplies an underground source of extra water to one well. Communities together with project staff carry out site selection, and then detailed design/estimates/layout is done with project technical assistance. As a supportive measure the catchment area is treated with gully plugs (small stone checks in gullies). A water harvesting tank (small reservoir or dam) may be excavated above the series of dohs where this is justified by a sufficiently large catchment area/suitable site. The capacity of the tank at Mohanpada is around 600 m3 and thus also has a positive impact on groundwater recharge.

Natural / human environment: Maintenance is agreed through meetings of user groups: manual desilting is planned and repairs of gully plugs also. In summary, dohs are low cost water recharge alternatives for poorer communities, and in this case study, the extra area brought under production has meant that all families that require it, now have access to some water for irrigation.

2.3 Fotos da tecnologia

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

País:

Índia

Região/Estado/Província:

Madhya Pradesh

Especificação adicional de localização:

Ratlam, Mohanpada

Comentários:

Total area covered by the SLM Technology is 0.1 km2.

The project area for phase 1 comprises 18 villages (3314 Households) mainly tribal. A significant portion of the area is barren and used for open grazing. The sunken wter harvesting technology was initially demonstrated in few villages as an alternative to the high cost heading type approach to water harvesting bieng implemented on a large scale by main line programmes.

2.6 Data da implementação

Caso o ano exato seja desconhecido, indique a data aproximada:
  • mais de 50 anos atrás (tradicional)

2.7 Introdução da tecnologia

Especifique como a tecnologia foi introduzida:
  • através de projetos/intervenções externas
Comentários (tipos de projeto, etc.):

The technology which is a modification of the traditional 'DOH' observed in river beds was implemented on an experimental basis in village Ambaohondan Tehsil 0 Mau, Dist. Indore under NWDPRA by Mr. V.K.Agrawal & Mr.V.V.Karmarkar.

3. Classificação da tecnologia de GST

3.1 Principal/principais finalidade(s) da tecnologia

  • Melhora a produção

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

Uso do solo misturado dentro da mesma unidade de terra:

Sim

Especificar o uso misto da terra (culturas/ pastoreio/ árvores):
  • Agropecuária (incl. agricultura e pecuária)

Terra de cultivo

Terra de cultivo

  • Cultura anual
Cultivo anual - Especificar culturas:
  • culturas de fibras - algodão
  • legumes e leguminosas - ervilhas
  • legumes - outros
  • wheat, chili peppers
Número de estações de cultivo por ano:
  • 2
Especifique:

Longest growing period in days: 120 Longest growing period from month to month: Jul - Oct

Pastagem

Pastagem

  • Extensive grazing
Comentários:

Major land use problems (compiler’s opinion): There are regular poor yields of agricultural crops on the degraded, rainfed fields. A further constraint is the limited amount of water in wells, restricting both the extent of irrigation, and the number of people with access to irrigation. There is an underlying problem of poverty, which in turn leads to seasonal out-migration to find work.

Major land use problems (land users’ perception): Agricultural lands: sloping fields, soil loss, poor yields. Common lands:competition from surrounding villages for grazing resulting in low yields. Private pastures (bir): small patches which are not sufficient to meet the fodder needs. Settlement area: 28 huts already erected. Additional space not available.

Other grazingland: extensive grazing: on patches of waste lands within fields

Type of cropping system and major crops comments: During monsoon (kharif) season the main crop is cotton + maize. In addition minor pulses are taken. If water is available for irrigation, this is followed by wheat+gram in winter. Major area is fallow in winter except for the cotton crop which is of longer duration. No cultivation was observed in summer.

3.4 Abastecimento de água

Abastecimento de água para a terra na qual a tecnologia é aplicada:
  • Precipitação natural
Comentários:

Water supply: Also mixed rainfed - irrigated

3.5 Grupo de GST ao qual pertence a tecnologia

  • Coleta de água
  • Gestão de irrigação (inclusive abastecimento de água, drenagem)
  • Gestão de água de superfície (nascente, rio, lagos, mar)

3.6 Medidas de GST contendo a tecnologia

Medidas estruturais

Medidas estruturais

Comentários:

Main measures: structural measures

3.7 Principais tipos de degradação da terra abordados pela tecnologia

Erosão do solo pela água

Erosão do solo pela água

  • Wg: Erosão por ravinas/ravinamento
Degradação da água

Degradação da água

  • Ha: aridificação
Comentários:

Main type of degradation addressed: Wg: gully erosion / gullying, Ha: aridification

Main causes of degradation: other human induced causes (specify) (Social causes = Lack of awareness and mobilisation amongst the communities.), Top down approach (Macro planning rather than micro (village level) planning.)

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. Especificações técnicas, implementação de atividades, entradas e custos

4.1 Desenho técnico da tecnologia

Especificações técnicas (relacionada ao desenho técnico):

Overview of sunken streambed structures (doh) with associated wells and irrigated plots. Note that several dohs are applied in series along the waterway.

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: low

Main technical functions: increase of infiltration, water harvesting / increase water supply

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

Structural measure: doh (sunken streambed structure)

Structural measure: dam, gully plugs (supp.)

Construction material (stone): used for silt trap on the upstream side

Construction material (other): weathered section is excavated manually, while hard rock beds may be excavated by machine, dynamite.

Autor:

Mats Gurtner

4.2 Informação geral em relação ao cálculo de entradas e custos

Outro/moeda nacional (especifique):

Rupees

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

48,85

Indique a média salarial da mão-de-obra contratada por dia:

1.00

4.3 Atividades de implantação

Atividade Periodicidade (estação do ano)
1. Site selection with community by eye Dry season
2. Identification of beneficiaries and user groups Dry season
3. Design & estimation by project staff Dry season
4. Agreement of village committee. Dry season
5. Treatment of catchment with gully plug Dry season
6. Excavation of Dohs (200–400 m3) as last action with silt traps upstreamof each made from loose stone. Dry season
7. Wells (odees) may be deepened and pumps bought Dry season

4.4 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 Labour ha 1,0 225,0 225,0 25,0
Equipamento Tools ha 1,0 15,0 15,0 100,0
Custos totais para a implantação da tecnologia 240,0
Custos totais para o estabelecimento da Tecnologia em USD 4,91
Comentários:

Duration of establishment phase: 12 month(s)

4.5 Atividades recorrentes/manutenção

Atividade Periodicidade/frequência
1. Maintenance of catchment treatments (desilting of gully plugs etc) Dry Season/if required
2. Meeting of User Group Monsoon/After heavy Showars
3. Repairs to Silt-trap During monsoon/After heavy shower
4. Desilting of DOH Dry Season/annual

4.6 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 Labour ha 1,0 5,0 5,0 100,0
Custos totais para a manutenção da tecnologia 5,0
Custos totais de manutenção da Tecnologia em USD 0,1
Comentários:

The construction of one doh costs between US$ 200-400, depending on the size of the doh (approximately one cubic metre can be excavated per person day at a cost of one US dollar). On a per hectare basis the costs are very variable, since they are related to the extra area brought under irrigation. In this case study there are four dohs within a total village area of 50 ha. Ten of the 50 ha have been brought into irrigated production (extra to the 5 ha already irrigated) due to the four dohs and the ‘tank’ and the costs outlined above are spread over those 10 ha. In this case half of the costs are directly attributable to dohs (average capacity 400 m3 each), and half to catchment treatment where the water-harvesting tank (a reservoir of approximately 600 m3) is the main cost. Where there is underlying rock, mechanical drills and blasting by dynamite may be required, which increases the costs. That was not the case in this village. The cost of deepening/widening the five wells (odees) has not been included here: that is carried out by the villagers themselves. While the project normally pays around 85% of labour costs, here at Mohanpada village the project only needs to pay 75%, due to a high level of commitment by the villagers.

The total of 4 doh structure were constructed along a stream length of 451 m having gradient of 1.2%. Total storage capacity is 1646qm. It is observed that during past year (2002) the structures were completely filled & subsequently emptied (percolated) 5 times.

4.7 Fatores mais importantes que afetam os custos

Descreva os fatores mais determinantes que afetam os custos:

Presence of hard stata (bed rock) increases cost of excavation

5. Ambiente natural e humano

5.1 Clima

Precipitação pluviométrica anual
  • <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
Especifique a média pluviométrica anual em mm (se conhecida):

800,00

Especificações/comentários sobre a pluviosidade:

However since past 4 years rainfall has been below average

Zona agroclimática
  • Semiárido

Located on the tropic of cancer, characterised by hot dry summers (max 46 deg C) and cold dry winters. Monsoon (July-Sept) is characterised by high intensity showers followed by prolonged dry spells.

5.2 Topografia

Declividade média:
  • Plano (0-2%)
  • Suave ondulado (3-5%)
  • Ondulado (6-10%)
  • Moderadamente ondulado (11-15%)
  • Forte ondulado (16-30%)
  • Montanhoso (31-60%)
  • Escarpado (>60%)
Formas de relevo:
  • Planalto/planície
  • Cumes
  • Encosta de serra
  • Encosta de morro
  • Sopés
  • Fundos de vale
Zona de altitude:
  • 0-100 m s.n.m.
  • 101-500 m s.n.m.
  • 501-1.000 m s.n.m.
  • 1.001-1.500 m s.n.m.
  • 1.501-2.000 m s.n.m.
  • 2.001-2.500 m s.n.m.
  • 2.501-3.000 m s.n.m.
  • 3.001-4.000 m s.n.m.
  • > 4.000 m s.n.m.
Comentários e outras especificações sobre a topografia:

Slopes on average: Also gentle (ranked 2) and moderate (ranked 3)

5.3 Solos

Profundidade do solo em média:
  • Muito raso (0-20 cm)
  • Raso (21-50 cm)
  • Moderadamente profundo (51-80 cm)
  • Profundo (81-120 cm)
  • Muito profundo (>120 cm)
Textura do solo (solo superficial):
  • Grosso/fino (arenoso)
  • Médio (limoso, siltoso)
Matéria orgânica do solo superficial:
  • Alto (>3%)
  • Médio (1-3%)
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: Very shallow (ranked 1, eroded wastelands, fields on slopes) and shallow (ranked 2, fields in valley portion)
Soil texture: Medium (ranked 1, present in valley sections) and coarse/light (ranked 2, present along slopes)
Soil fertility: Low (ranked 1, fields along slopes,waste lands) and medium (ranked 2, fields in valley section)
Topsoil organic matter: High (ranked 1, fields along slopes, waste lands) and medium (ranked 2, fields in valley sections)
Soil drainage/infiltration: Medium
Soil water storage capacity: Low

5.6 Características dos usuários da terra que utilizam a tecnologia

Orientação de mercado do sistema de produção:
  • misto (subsistência/comercial)
Rendimento não agrícola:
  • 10-50% de toda renda
Nível relativo de riqueza:
  • Muito pobre
  • Pobre
Nível de mecanização:
  • Trabalho manual
  • Tração animal
Indique outras características relevantes dos usuários da terra:

Population density: > 500 persons/km2
Annual population growth: > 4%
1% of the land users are average wealthy (One family has bore-well).
19% of the land users are poor (Few farmers have access to shallow wells.).
80% of the land users are poor (Majority are small/marginal farmers without access to irrigation).
Off-farm income specification: some migratory work in nearby towns and in large scale mechanised farms during peak periods (note: now there is less migration as a result of increased irrigation)

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

  • < 0,5 ha
  • 0,5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1.000 ha
  • 1.000-10.000 ha
  • > 10.000 ha

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

Propriedade da terra:
  • Comunitário/rural
  • Indivíduo, intitulado
Direitos do uso da terra:
  • Acesso livre (não organizado)
  • Indivíduo

6. Impactos e declarações finais

6.1 Impactos no local mostrados pela tecnologia

Impactos socioeconômicos

Produção

Produção agrícola

diminuído
aumentado
Renda e custos

Rendimento agrícola

diminuído
aumentado

Disparidades econômicas

aumentado
diminuído
Comentários/especificar:

Increased economic inequity in some villages, between those with wells and those without

Impactos socioculturais

Instituições comunitárias

Enfraquecido
Fortalecido

Conhecimento de GST/ degradação da terra

Reduzido
Melhorado

Atenuação de conflitos

Agravado
Melhorado
Comentários/especificar:

Increased economic inequity in some villages, between those with wells and those without

Impactos ecológicos

Ciclo hídrico/escoamento

Lençol freático/aquífero

reduzido
Recarga
Solo

Umidade do solo

diminuído
aumentado

Cobertura do solo

Reduzido
Melhorado
Comentários/especificar:

Where cultivated

Perda de solo

aumentado
diminuído
Comentários/especificar:

In catchment

6.2 Impactos externos mostrados pela tecnologia

Caudal confiável e estável em período seco

Reduzido
aumentado

Cheias de jusante

aumentado
Reduzido

Sedimentação a jusante

aumentado
diminuído

Poluição de água subterrânea/rio

aumentado
Reduzido

Amount of water to downstream users

reduced
improved

6.4 Análise do custo-benefício

Como os benefícios se comparam aos custos de implantação (do ponto de vista dos usuários da terra)?
Retornos a curto prazo:

positivo

Retornos a longo prazo:

muito positivo

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

positivo

Retornos a longo prazo:

muito positivo

6.5 Adoção da tecnologia

Comentários:

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

1600 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: estimates

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: Farmers in Mohanpada have constructed one doh with only 10 % subsidy on the total cost.
Spontaneous adoption is growing in neighbouring villages.

6.7 Pontos fortes/vantagens/oportunidades da tecnologia

Pontos fortes/vantagens/oportunidades na visão do compilador ou de outra pessoa capacitada
Dohs are a low cost alternative method of increasing groundwater in a semi-arid area where production of high value legumes depends on irrigation
– and dohs represent the best way in this situation of expanding the extent of irrigated land, and bringing irrigation to more families.
Small, multiple recharge points for replenishing groundwater for irrigation
from wells

How can they be sustained / enhanced? Breaking hard pan in stream bed mechanically by drills or blasting to deepen dohs and thereby make them more effective.
No risk of breaches of bunds as the structures are sunken below ground.

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

Pontos fracos/vantagens/riscos na visão do compilador ou de outra pessoa capacitada Como eles podem ser superados?
Group maintenance is required Form user groups.
Villagers are more used to (and may prefer) larger and deeper ‘tanks’ Establish more dohs to create more impact.
Dohs are limited in capacity and thus dry up quickly, as do the wells Establish more dohs to create more impact.

7. Referências e links

7.1 Métodos/fontes de informação

Módulos