Tecnologías

Submerged drains [Países Bajos]

Creación: 30/10/2015 12:29
Actualización: 05/06/2019 15:44
Compilador: Simone Verzandvoort
Editor: –
Revisores: Fabian Ottiger, Alexandra Gavilano

Onderwaterdrains (NL)

technologies_1704 - Países Bajos

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1. Información general

1.2 Detalles de contacto de las personas de referencia e instituciones involucradas en la evaluación y la documentación de la Tecnología

Persona(s) de referencia clave

Especialista MST:

Van de Akker Jan J.H.

Wageningen Environmental Research (Alterra)

Países Bajos

Especialista MST:

Simone Verzandvoort

Nombre del proyecto que financió la documentación/ evaluación de la Tecnología (si fuera relevante)

Preventing and Remediating degradation of soils in Europe through Land Care (EU-RECARE )

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Wageningen Environmental Research (Alterra) - Países Bajos

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Provincie Holland Zuid - Países Bajos

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Provincie Utrecht - Países Bajos

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

LTO NOORD - Países Bajos

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Waterschap Amstel, Gooi en Vecht - Países Bajos

1.3 Condiciones referidas al uso de datos documentados mediante WOCAT

El compilador y la/s persona(s) de referencia claves aceptan las condiciones acerca del uso de los datos documentados mediante WOCAT:

Sí

2. Descripción de la Tecnología MST

2.1 Breve descripción de la Tecnología

Definición de la Tecnología:

Submerged drains are drains installed in grassland on peatsoils with the aims to decrease soil subsidence and emission of CO2 and N2O due to the oxidation of peat soil, and to maintain suitable groundwater levels in fields for grassland production and grazing.

2.2 Descripción detallada de la Tecnología

Descripción:

Contrary to usual drains, submerged drains are installed below ditchwater level. Submerged drains diminish the differences between ditch level and groundwater level in the fields by enabling the infiltration from ditch to field and the drainage from field to ditch.
In summer and dry periods the infiltration from ditch to field is much lower than the evapotranspiration of the grass, resulting in a lowering of the groundwater level some decimetres below ditch water level. With submerged drains the groundwater level is lowered less drastically because infiltration from ditch to field is improved. In winter and wet periods, fields are drained more quickly compared to conventional drainage.

Purpose of the Technology: Submerged drains diminish the differences between ditch level and groundwater level in the fields by enabling the infiltration from ditch to field and the drainage from field to ditch. Under peak rainfall events groundwater levels become less high and remain at high levels for shorter times than in fields without submerged drains.
Due to the increased groundwater level in summer the decomposition of the peat soil is reduced. As a result, the rate of soil subsidence is decreased and also the emission of greenhouse gases and of N and P released to the surface water.

Establishment / maintenance activities and inputs: The installation of submerged drains is done with common drainage installation machines. Submerged drains should be installed between 15 and 25 cm below the ditch water level, and between 45 and 75 cm below the soil surface. The drain pipes should have a diameter of at least 6 cm. The distance between drains is at most 6 m. Drain length is at most 300 m. Submerged drains can be installed in the length or width direction of a field. Drains must be installed level.

Natural / human environment: Submerged drains were designed for peat soils under permanent pasture for dairy farming. More than 70 % of Dutch peat soils are under this land use. Drainage of these peat soils results in subsidence, mainly by decomposition (oxidation) of the peat (partly by shrinkage and consolidation). This is an ongoing process, because every 10 to 15 year ditchwater levels are adapted to the lowered surface in order to enable dairy farming and to prevent the conversion to wetlands. Soil subsidence causes several problems: decreased suitability for grazing and grassland farming, increased flood risk, emission of greenhouse gases, damage to infrastructure (dikes, roads, foundations, sewerage networks) and increased cost of water management.

Submerged drains were tested with a network of practitioners and 10 dairy farmers in the Dutch peat soil area between 2011 and 2013 on an area of 20 ha.

2.3 Fotografías de la Tecnología

Galería de medios

2.5 País/ región/ lugares donde la Tecnología fue aplicada y que se hallan comprendidos por esta evaluación

País:

Países Bajos

Región/ Estado/ Provincia:

The Netherlands/Province of Zuid-Holland

Especifique más el lugar :

Krimpenerwaard

Especifique la difusión de la Tecnología:

distribuida parejamente sobre un área

Si la Tecnología se halla difundida homogéneamente a lo largo de un área, especifique el área que cubre (en km2):

0,054

Comentarios:

Total area covered by the SLM Technology is 0.054 m2.

The measure was tested in three pilots in the areas Krimpenerwaard, Keulevaart and Demmerkiksekade. Each pilot covered two fields: one with submerged drains and one without. The area given refers to the pilot in the Krimpenerwaard.

2.6 Fecha de la implementación

Si no se conoce el año preciso, indique la fecha aproximada:

hace menos de 10 años (recientemente)

2.7 Introducción de la Tecnología

Especifique cómo se introdujo la Tecnología:

durante experimentos/ investigación
mediante proyectos/ intervenciones externas

stimulated by regional authorities

Comentarios (tipo de proyecto, etc.):

Since 2003 submerged drains have been applied on several experimental farms in The Netherlands. Implementations over larger areas (i.e. a water management unit, 'peilval' in Dutch) will be done in 2016.

2007: research on soil subsidence in the Western peat area following the large scale groundweter level lowering in the 1960s and 1970s signalled the high rate of soil subsidence (5-12 mm/y) (Van den Akker et al., 2007a)

2008: concerns about soil subsidence in the western peat area from the provincial autorities of Noord-Holland, Utrecht and Zuid-Holland in the policy document 'Voorloper Groene Hart' (2008)

2008-2012: various research projects to test the effectiveness of submerged drains to reduce soil subsidence and to improve conditions for dairy farming, and on the effects for water quality: www.waarheenmethetveen.nl, Hoving et al. (2008), Woestenburg (2009), EU project EUROPEAT, Woestenburg et al. 2009; Jansen et al., 2010; Hendriks and Van den Akker, 2012; Hoving et al. (2008, 2009, 2013)

2011-2012: research on the Peat Area Innovation Centre (VIC) to test effects of submerged drainage in combination with dynamic groundwater level management (Hoving et al., 2013)

2012- testing by research instsiutes of economic viability of submerged drains with regard to water level management and agricultural productivity, on assignment of the province Noord-Holland, waterboard Hollands Noorderkwartier.

2009-2011: various modelling studies assigned by the provinces and water boards of the western peat meadow area on the effects of submerged drains for the demand for inlet and discharge of water and effects on the decomposition of peat and the water quality.

2011: model research on effects of submerged drains on the water demand of the western peat area until 2050 under climate change (Van den Akker et al., 2011)

2010-2013 experimental research in 3 pilots initiated by the province of Utrecht and Zuid-Holland, four water boards and the farmers' organisation LTO Noord. Aim: to test if the application of submerged drains results in larger amounts of water to supply and to discharge from the peat meadow area, and to test if the submerged drains result in a larger load of nutrients to ditches,

3. Clasificación de la Tecnología MST

3.2 Tipo(s) actuales de uso de la tierra donde se aplica la Tecnología

Tierra de pastoreo

Pastoreo intensivo/ producción de forraje:

Pastoreo mejorado

cows

Comentarios:

Major land use problems (compiler’s opinion): The major land use problems in the Western Dutch peat soil area is soil subsidence due to the lowering of the groundwater level in the 1960s and 1970s. The soil subsidence amounts to 0-2.5 cm per year. It is mainly caused by the oxidation of peat soil, which releases nutrients to soil and surface water, and CO2 and N2O to the atmosphere. The soil subsidence causes several problems:
- damage to buildings and infrastructure
- increasing costs of water management: high groundwater levels require pumping of water to enable agricultural use, and storage of rainfall excess water during peak rainfall events
- drainage of nature reserves to lowered agricultural land
- water pollution: the lowering of the groundwater level causes upward seepage of nutrient-rich water to polders
- greenhouse gas emissions (2-3% of total CO2 emissions in The Netherlands)
- loss of peat soils (2% per year in the NL)
- increased flood risk (due to combination with sealevel rise)

Major land use problems (land users’ perception): Grassland and arable farming are hampered by high groundwater levels due to a lowered bearing capacity and too wet conditions for crops. Maintaining the groundwater level at a level high enough to prevent the decomposition of peat soil would imply a conversion to wetlands and forest swamps. This is not acceptable to various kinds of land users (nature managers, farmers, users of built-up area). This would also mean the loss of the cultural historic open landscape and habitat for meadow birds, strongly reduced economic possibilities and an increased demand of water from the rivers (view of water managers and governments).

Future (final) land use (after implementation of SLM Technology): Grazing land: Gi: Intensive grazing/ fodder production

Longest growing period in days: 270Longest growing period from month to month: April-October
Livestock density: > 100 LU /km2

3.3 ¿Cambió el uso de tierras debido a la implementación de la Tecnología?

¿Cambió el uso de tierras debido a la implementación de la Tecnología?

Sí (Por favor responda las preguntas de abajo referidas al uso de la tierra antes de implementar la Tecnología)

Tierra de pastoreo

Intensive grazing/ fodder production

3.4 Provisión de agua

Provisión de agua para la tierra donde se aplica la Tecnología:

de secano

3.5 Grupo MST al que pertenece la Tecnología

diversión y drenaje de agua
manejo de agua subterránea

3.6 Medidas MST que componen la Tecnología

medidas estructurales

S4: Acequias niveladas, fosas

medidas de manejo

M7: Otros

Comentarios:

Main measures: management measures

Specification of other management measures: maintaining high groundwater level

3.7 Principales tipos de degradación del suelo encarados con la Tecnología

deterioro químico del suelo

Cn: reducción de la fertilidad y contenido reducido de la materia orgánica del suelo (no ocasionados por la erosión)

deterioro físico del suelo

Pw: encharcamiento
Ps: hundimiento de suelos orgánicos, asentamiento del suelo

degradación del agua

Hg: cambio en nivel de aguas subterráneas/ nivel de acuífero
Hq: reducción de la calidad de subterráneas

Comentarios:

Main type of degradation addressed: Cn: fertility decline and reduced organic matter content, Ps: subsidence of organic soils, settling of soil

Secondary types of degradation addressed: Pw: waterlogging, Hg: change in groundwater / aquifer level, Hp: decline of surface water quality

Main causes of degradation: other human induced causes (specify) (lowering of the groundwater level to enable agricultural use of the peat soils results in soil subsidence and detioration of ground- and surface water quality due to capillary rise)

Secondary causes of degradation: change in temperature (higher temperatures under climate change increase the decomposition rate of peat soil; subsidence and CO2 emissions will increase by 75%), change of seasonal rainfall (decrease in summer rainfall (23% in warm and dry CC scenario for NL)), inputs and infrastructure: (roads, markets, distribution of water points, other, …) (maintenance of high water levels in built-up and natural areas increases the difference in groundwater level with agricultural land onb peat soils)

3.8 Prevención, reducción o restauración de la degradación del suelo

Especifique la meta de la Tecnología con relación a la degradación de la tierra:

reducir la degradación del suelo

4. Especificaciones técnicas, actividades de implementación, insumos y costos

4.1 Dibujo técnico de la Tecnología

Especificaciones técnicas (relacionadas al dibujo técnico):

The picture shows a cross section through an agricultural field, bounded by two ditches. A submerged drain (yellow bar in the picture) is installed at 80 cm below the soil surface. It ends in the ditch on the left side at 20 cm below the water level in the ditch. The dotted line indicates the position of the groundwater table in the situation without the submerged drain; the continuous blue line indicates the position in the situation where the submerged drain is installed. The lines show that in summer the groundwater level is raised to nearly the level of the ditch water by the submerged drain, whereas the level would be approximately 30 cm lower without the drain.
In winter, in the situation with the submerged drain, the groundwater level is around 40 cm below the soil surface. This enables the farmer to use the field for grazing or to traffic the field. However, in the situation without the drain, the groundwater level nearly reaches the soil surface in the centre of the field, impeding traffic or grazing on the field.

Technical knowledge required for field staff / advisors: moderate (Estimates of economic benefits due to increased grass production and grazing periods vary between years with meteorological conditions.)

Technical knowledge required for land users: moderate (Specific conditions apply to the dimensions and positioning of submerged drains in the fields. Level position and lebgth are critical.)

Technical knowledge required for companies installing the drains: moderate (Specific conditions apply to the dimensions and positioning of submerged drains in the fields. Level position and lebgth are critical. Soil must have sufficient bearing capacity during installation.)

Technical knowledge required for water board: moderate (submerged drains increase the water supply and discharge from groundwater level management units. Additional pumping effort can be prevented by informed water level management.)

Technical knowledge required for researchers: (the implications of submerged drains on the water management in an entire management unit should be explored using coupled hydraulic and rainfall-runoff models.)

Main technical functions: improvement of topsoil structure (compaction), maintaining soil organic matter

Secondary technical functions: increase of infiltration, increase / maintain water stored in soil, drainage of excess rainfall

Other type of management: Maintaining high groundwater levels.

Autor:

Jan van den Akker, Alterra, Droevendaalsesteeeg 3, 6708 PB Wageningen, The Netherlands

4.2 Información general sobre el cálculo de insumos y costos

otra / moneda nacional (especifique):

euro

Si fuera relevante, indique la tasa de cambio de dólares americanos a la moneda local (ej. 1 U$ = 79.9 Reales Brasileros): 1 U$ =:

1,09

4.3 Actividades de establecimiento

	Actividad	Momento (estación)
1.	maintenance of drains and outlet in ditch
2.	installation of submerged drains	in dry periods

4.4 Costos e insumos necesarios para el establecimiento

	Especifique insumo	Unidad	Cantidad	Costos por unidad	Costos totales por insumo	% de los costos cubiertos por los usuarios de las tierras
Mano de obra	maintenance of drains and outlet in ditch	ha	1,0	30,14	30,14	100,0
Mano de obra	installation of submerged drains	ha	1,0	1980,0	1980,0	100,0
Costos totales para establecer la Tecnología					2010,14
Costos totales para establecer la Tecnología en USD					1844,17

Comentarios:

Lifespan of the drains: 30 years

4.5 Actividades de establecimiento/ recurrentes

	Actividad	Momento/ frequencia
1.	maintenance of submerged drains	several times in lifetime of drains (30 y)

4.6 Costos e insumos necesarios para actividades de mantenimiento/ recurrentes (por año)

	Especifique insumo	Unidad	Cantidad	Costos por unidad	Costos totales por insumo	% de los costos cubiertos por los usuarios de las tierras
Otros	Annual cost incl maintenance	ha	1,0	127,0	127,0	100,0
Indique los costos totales para mantenecer la Tecnología					127,0
Costos totales para mantener la Tecnología en USD					116,51

Comentarios:

Machinery/ tools: establishment and installation require specific skills and machinery; hired, not done by the farmer himself

Investment costs of 1500-1800 €/ha are based on submerged drains at 6 m distance. Costs per m of drain establishment based on drains of 6 cm diameter. Costs based on practical experience from farmers. Drains may have a lifetime of 30 years and require little maintenance.

Specific skills and machinery are required for installation and maintenance, hired from a drainage company. The farmer must only ensure that the outlets of the drains in the ditches remain open and undamaged.

4.7 Factores más determinantes que afectan los costos:

Describa los factores más determinantes que afectan los costos:

We do not have information on specific cost items, only on establishment costs ad between 1500 and 1800 euro/ha, and annual cost of 117 €/ha incl maintenance, assuming a 20-year life time. Establishment costs can also be expressed per m of drain, i.e. 1.10 EURO per m including materials (drain of 6 cm diameter).

Determinate factors include size and geometry of fields; installation in the length direction is cheaper, and results in fewer outlets in the receiving ditch.

5. Entorno natural y humano

5.1 Clima

Lluvia 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

Especificaciones/ comentarios sobre la cantidad de lluvia:

Distribution of rainfall over the year: 23% (winter), 19% (spring), 27% (summer) and 31% (autumn)

Zona agroclimática

húmeda
Sub-húmeda

Thermal climate class: temperate

5.2 Topografía

Pendientes en promedio:

plana (0-2 %)
ligera (3-5%)
moderada (6-10%)
ondulada (11-15%)
accidentada (16-30%)
empinada (31-60%)
muy empinada (>60%)

Formaciones telúricas:

meseta/ planicies
cordilleras
laderas montañosas
laderas de cerro
pies de monte
fondo del valle

Zona altitudinal:

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

Comentarios y especificaciones adicionales sobre topografía :

Altitudinal zone: 0-100 m a.s.l. (Submerged drains are designed for polders in lowland areas on peat soils)
Landforms: Plateau/plains (submerged drains are designed to drain level fields)
Slopes on average: Flat (submerged drains are designed to drain flat terrain, based on hydraulic prressure head differences between field and ditch)

5.3 Suelos

Profundidad promedio del suelo:

muy superficial (0-20 cm)
superficial (21-50 cm)
moderadamente profunda (51-80 cm)
profunda (81-120 cm)
muy profunda (>120 cm)

Textura del suelo (capa arable):

fina/ pesada (arcilla)

Materia orgánica de capa arable:

elevada (>3%)

Si se halla disponible, adjunte una descripción completa de los suelos o especifique la información disponible, por ej., tipo de suelo, pH/ acidez de suelo, capacidad de intercambio catiónico, nitrógeno, salinidad, etc. :

Soil depth on average: Very deep (if the peat substrate is considered as part of the soil profile, soils are deeper than 120 cm, with peat packages up to 13 m in some parts of the western Dutch peatland area) and shallow (If the top of the C-horizon is considered as the bottom of the soil profile. C-horizons typically start at 15-30 cm below the soil surface)
Soil texture is fine/heavy (for peat soils with a clayey top layer. In peat soils without such a top layer, a soil texture indication is not applicable. Peat soils are defined as having at least 40 cm of peat in the top 80 cm)
Soil fertility is very high (peat soils are able to supply ample nutrients to plants provided that they are well drained)
Topsoil organic matter is high (Organic matter contents in the topsoil are above 20%. Peat soils are defined as having at least 40 cm of peat in the top 80 cm according to the Dutch soil classification system)
Soil drainage/infiltration is poor/none (peat soils inherently have poor drainage due to their low position with reference to the groundwater level in the regional water system. Values of Ksat reported 2.9-5.0 cm/d)
Soil water storage capacity is very high (the soil water storage capacity is very high due to the large pore space (0.70-0.90 m3/m3))

5.4 Disponibilidad y calidad de agua

Agua subterránea:

< 5 m

Disponibilidad de aguas superficiales:

bueno

Calidad de agua (sin tratar):

solo para uso agrícola (irrigación)

Comentarios y especificaciones adicionales sobre calidad y cantidad de agua:

Ground water table: <5m (Average lowest grondwater level in the pilot region is 5-10 cm below the soil surface; average highest level 55-65 cm)
Availability of surface water is good (surface water is amply available due to the low position of the peat soil area compared to the mean sea level, and due to the dense network of ditches and other surface water conveyors and bodies) and excess (surface water levels are under continuous control by the water boards. Therefore flood situations do not occur, but under high-intensity rainfall events fields may submerge)
Water quality (untreated) is for agriculutral use only (Irrigation, surface and groundwater can be used for agriculture without treatment. Nutrient rich water emerging by capillary rise in polders may not be suitable for nature.)
Biodiversity is medium (the grasslands in the western peatsoil area are suitable habtitats for meadow birds)

5.5 Biodiversidad

Diversidad de especies:

mediana

5.6 Las características de los usuarios de la tierra que aplican la Tecnología

Orientación del mercado del sistema de producción:

comercial/ mercado

Ingresos no agrarios:

menos del 10% de todos los ingresos

Nivel relativo de riqueza:

promedio

Individuos o grupos:

individual/ doméstico

Indique otras características relevantes de los usuarios de las tierras:

Difference in the involvement of women and men: Executives of agricultural enterprises in The Netherlands are usually men.
Population density: 200-500 persons/km2
Annual population growth: 1% - 2%
100% of the land users are average wealthy and own 100% of the land.
Off-farm income specification: Dairy farmers in this part of The Netherlands spend 100% of their time on the farm. Sometimes their wives have jobs earning off-farm income.
Market orientation is commercial/market (intensive dairy farming in the NL produces for the market)

5.7 Área promedio de la tierra usada por usuarios de tierra que aplican la Tecnología

< 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

Comentarios:

On average, Dutch dairy farms have 50 ha grazing land for 90 dairy cows (2013).

5.8 Tenencia de tierra, uso de tierra y derechos de uso de agua

Tenencia de tierra:

individual, con título

Derechos de uso de tierra:

individual

Derechos de uso de agua:

arrendamiento

5.9 Acceso a servicios e infraestructura

salud:

pobre
moderado
bueno

educación:

pobre
moderado
bueno

asistencia técnica:

pobre
moderado
bueno

empleo (ej. fuera de la granja):

pobre
moderado
bueno

mercados:

pobre
moderado
bueno

energía:

pobre
moderado
bueno

caminos y transporte:

pobre
moderado
bueno

agua potable y saneamiento:

pobre
moderado
bueno

servicios financieros:

pobre
moderado
bueno

6. Impactos y comentarios para concluir

6.1 Impactos in situ demostrados por la Tecnología

Impactos socioeconómicos

Producción

producción de forraje

disminuyó

incrementó

Cantidad antes de MST:

10.7-12.4 tons DM/ha11575

Cantidad luego de MST:

9.8-12.4 ton DM/ha10975

Comentarios/ especifique:

Net grass yields (DM) measured on experimental plots. May slightly decrease due to SMD, but less loss due to trampling, increased length of grazing season. This delivers 500 kg DM/ha extra fodder produced and 30 extra grazing days.
But also loss possible: From 11575 kg DM/ha to 10975 kg DM/ha Decrease in grass yield is possible between 3 and 9%. This does not take into account losses due to tramping in situation without drains and longer grazing season under SMD.

calidad de forraje

disminuyó

incrementó

Cantidad antes de MST:

275-417 kg N/ha

Cantidad luego de MST:

235-389 kg N/ha

Comentarios/ especifique:

Slight decrease in N and P content of grass, but quality of grass is expected to improve due to better drained soil and improved bearing capacity

riesgo de fracaso de producción

incrementó

disminuyó

Comentarios/ especifique:

SMD enable a longer grazing season, increased bearing capacity and reduced risk of flooding of fields

Ingreso y costos

gastos en insumos agrícolas

incrementó

disminuyó

Comentarios/ especifique:

reduced additional feedstock; benefits of extra grass yields and grazing days amount to 171 euro/ha

ingreso agrario

disminuyó

incrementó

Comentarios/ especifique:

net benefits of installing SMD are approx. 54 euro per ha per year

carga de trabajo

incrementó

disminuyó

Comentarios/ especifique:

trafficability and workability of fielfds improved due to drier topsoil conditions and increased bearing capacity

Otros impactos socioeconómicos

inlet and drainage of water

Comentarios/ especifique:

SMD require an increased inlet and drainage of water in the ditches by the water board, increased pumping hours: 10-22% in dry years; 7-12% in wet years.
Inlet: extra 36-86 mm/y in dry years, 19-45 mm in wet years
Drainage: 17-59 mm in dry years; 33-60 in wet year

Impactos socioculturales

instituciones comunitarias

se debilitaron

se fortalecieron

Comentarios/ especifique:

Community of Practice on SMD in peat soils enabled knowledge transfer between land users, research insttitutes, farmer's association and authorities

instituciones nacionales

se debilitaron

se fortalecieron

Comentarios/ especifique:

The CoP has informed water boards and provinces in the part of The Netherlands with problems due to soil subsidence

Improved livelihoods and human well-being

decreased

increased

Comentarios/ especifique:

The long-term experiments in The Netherlands, pilots and activities of the farmers organisation LO Nederland, the Veenweide Informatie Centrum and the Community of Practice Submerged Drainage on Peat soils have increased the understanding of participating farmers of submerged drainage, the water accounting of their land, soil and soil quality. Tjey acquired practical knowledge on the implementation of the technology. Participating farmers continue to exchange knowledge and intend to extend the area under SMD. As a result of the pilots and the activities of the Community of Practice, interest for submerged drainage was raised among other dairy farmers, policy makers and authorities.

Impactos ecológicos

Ciclo de agua/ escurrimiento de sedimento

calidad de agua

disminuyó

incrementó

Comentarios/ especifique:

slight decrease of export of N, P and SO4 to the surface water

drenaje de agua en exceso

disminuyó

mejoró

Comentarios/ especifique:

SMD increased drainage by 20-65 mm per year in 2011 and 2012

Suelo

humedad del suelo

disminuyó

incrementó

Comentarios/ especifique:

SMD increased infiltration by 8-93 mm per year in 2011 and 2012

compactación de suelo

incrementó

disminuyó

Comentarios/ especifique:

decreased soil subsidence to 50% (reductions of 3-6 and 5-8 mm/year)

Biodiversidad: vegetación, animales

diversidad animal

disminuyó

incrementó

Comentarios/ especifique:

no direct impact on breeding conditions for meadow birds

Reducción de riesgos de desastres y riesgos climáticos

emisión de carbono y gases de invernadero

incrementó

disminuyó

Comentarios/ especifique:

decreased GHG emissions in CO2 eq: 6.8-13.5 t/ha per year (pilot Keulevaart) and 11.3-18.1 (pilot Demmeriksekade)

Otros impactos ecológicos

Hazard towards adverse events

improved

reduced

Comentarios/ especifique:

quicker lowering of groundwater table after extreme rainfall events (1-5 days)

Water management

harder

easier

Comentarios/ especifique:

More easy water management in polders: Fewer sub-polders with fixed ditch water level; possibility to create areas with high and low surface levels

6.2 Impactos fuera del sitio demostrados por la Tecnología

daños a infraestructura pública / privada

incrementó

disminuyó

Comentarios/ especifique:

reduced costs of infrastructure protection (30% or 3.5 M€/year until 2100 in the Frisian peat meadow area)

Cost of regional water management

increased

decreased

Comentarios/ especifique:

due to smaller differences in water levels between water management units

6.3 Exposición y sensibilidad de la Tecnología al cambio climático gradual y a extremos relacionados al clima/ desastres (desde la percepción de los usuarios de tierras)

Cambio climático gradual

	Estación	Incremento o reducción	¿Cómo es que la tecnología soporta esto?
temperatura anual		incrementó	bien

Extremos (desastres) relacionados al clima

Desastres climatológicos:

	¿Cómo es que la tecnología soporta esto?
tormenta de lluvia local	bien
tormenta de viento	bien

Desastres climatológicos

	¿Cómo es que la tecnología soporta esto?
sequía	no se sabe

Desastres hidrológicos

	¿Cómo es que la tecnología soporta esto?
inundación general (río)	bien

Otras consecuencias relacionadas al clima

	¿Cómo es que la tecnología soporta esto?
periodo reducido de crecimiento	bien

Comentarios:

Under extreme rainfall events, submerged drains cannot prevent that the groundwater level rises to above the soil surface. However, the groundwater level will fall more quickly with submerged drainas than without, on average to 10 cm lower levels.

Effects of dry summers have not yet been measured in experiments.

6.4 Análisis costo-beneficio

¿Cómo se comparan los beneficios con los costos de establecimiento (desde la perspectiva de los usuarios de tierra)?

Ingresos a corto plazo:

ligeramente positivo

Ingresos a largo plazo:

positivo

¿Cómo se comparan los beneficios con los costos de mantenimiento/ recurrentes (desde la perspectiva de los usuarios de tierra)?

Ingresos a corto plazo:

ligeramente positivo

Ingresos a largo plazo:

positivo

Comentarios:

A longer grazing season and the extra yield of fodder are the basis for a viable implementation of submerged drainage for land users. The CBA considers establishment and maintenance costs together: establishment costs of € 1800,-/ha, discounted over 20 years, including maintenance, result in annual cost of € 117,-/ha (6.5% of the investment). Benefits include 500 kg DM/ha extra grass use and 30 extra grazing days. This would yield € 171/ha, resulting in a net saldo of € 54,-. In addition SMD are an investment in sustainable soil management, resulting in an increased economic value of the land in the long term.

6.5 Adopción de la Tecnología

Si tiene la información disponible, cuantifique (número de hogares y/o área cubierta):

De todos quienes adoptaron la Tecnología, ¿cuántos lo hicieron espontáneamente, por ej. sin recibir nada de incentivos/ materiales:

91-100%

Comentarios:

13 land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: The area under submerged drainage implemented by the 10 dairy farmers from the Community of Practice is 20 ha. The area under SMD in the three pilots described in this questionnaire is roughly an additional 0.05 km2 per farm.

There is a moderate trend towards spontaneous adoption of the Technology

Comments on adoption trend: Due to the growing interest in the peat soil area because of the relevance for climate mitigation and the economic risks of soil subsidence there is growing interest in SMD in combination iwth dynamic groundwater level management to reduce the rate of soil subsidence. Subsidy arrangements are in preparation, which will stimulate adoption of the technology by more dairy farmers.

6.7 Fuerzas/ ventajas/ oportunidades de la Tecnología

Fuerzas/ ventajas/ oportunidades desde la perspectiva del usuario de la tierra
Submerged drains increase the number of days with a good bearing capacity of grassland, and therefore enable a longer grazing season and less trampling of grass.
Higher effective yield in total.
Short term: slightly cost effective. Long term: good cost effective.

Fuerzas/ ventajas/ oportunidades desde la perspectiva del compilador o de otra persona de referencia clave
Submerged drains allow a strong reduction of soil subsidence and GHG emissions (at least 50%, even >50% if combined with higher ditch water levels). How can they be sustained / enhanced? Further implementation by dairy farmers in the peat-meadow area. For this purpose the Community of Practice is recommended, as well as the arrangement of subsidies and the active involvement of regional government and water board. This applies to all mentioned advantages.
The quality of surface water in ditches will slightly improve.
Less problems with difference between subsiding soil surfaces and constant water levels in lakes and high water ditches (along houses).
Less sub-polders with a certain fixed ditch water level, and possibility to create areas with a high surface level (with submerged drains) and a low surface level (without SD).

6.8 Debilidades/ desventajas/ riesgos de la Tecnología y formas de sobreponerse a ellos

Debilidades/ desventajas/ riesgos desde la perspectiva del usuario de la tierra	¿Cómo sobreponerse a ellas?
Grass yield is lower due to reduced mineralization of nitrogen.	Yield could be increased due to better usage of manure (better NUE). On the other hand yield is increased due to increased number of days with a good bearing capacity of grassland, and a longer grazing season and less trampling of grass.

Debilidades/ desventajas/ riesgos desde la perspectiva del compilador o de otra persona de referencia clave	¿Cómo sobreponerse a ellas?
Submerged drains require more inlet water to polders.	Reduction of inlet requirement is possible by smart water management. This implies water level margins of +/- 10 cm and the use of weather forecasting.
Submerged drains require a bit more pumping to drain water under extreme rain events.