Inovagri: International Workshop on Technology Innovations in Irrigation Theme 2, Round Table 4: Engineering of Land Drainage

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1 Inovagri: International Workshop on Technology Innovations in Irrigation Theme 2, Round Table 4: Engineering of Land Drainage Some developments in land drainage Julián Martínez Beltrán Ex Drainage and Salinity Management Officer, FAO Land and Water Division, Rome Head of the Sustainable Land and Water Management Unit, Centre for Water Studies, CEDEX, Madrid Fortaleza, Ceará, Brazil, May

2 Contents Irrigated agriculture: benefits and problems. Land drainage to control waterlogging and soil salinity. Some technology developments. Conclusions. References. 2

3 Irrigated agriculture and agricultural production; a global view Irrigated agriculture contributes to 40% of food production in 20% of the cultivated area (about 300 million hectares). Increase of about 6% of the irrigated area (mostly in developing countries) by Priority of improvement of land and water productivity in existing irrigated lands. 3

4 Irrigated agriculture in Spain Approximately: 3.4 million hectares irrigated. In 13% of the cultivated area. 55% of agricultural production comes from irrigated lands. 4

5 Some problems of irrigated agriculture Consumptive use of 70% of water resources. Water productivity is generally low. Waterlogging and salinity. Deterioration of the quality of the irrigation return flows (salts, micro-elements, fertilizers, pesticides). 5

6 Land degradation by salinity of groundwater About 11 percent of the global irrigated lands are affected by salinity Irrigated lands affected by soil salinity, Mendoza, Argentina 6

7 Global map of salt-affected soils Source: Global Network on Integrated Soil Management for Sustainable Use of Saltaffected Soils, FAO 7

8 Integrated management of salt-affected soils Hydraulic aspects: Irrigation Drainage Leaching Physical/mechanical aspects: Land smoothing Land levelling Deep ploughing Subsoiling Sanding Chemical aspects : Amendments Mineral fertilization Integrated management Agronomic aspects: Organic matter Mulching Green manure Cropping techniques Saline agriculture Other aspects to consider: Legal and environmental Socio-economic aspects 8

9 Land drainage to control waterlogging and soil salinity Drainage systems, Lower Guadalquivir, Spain 9

10 Subsurface drainage to control saline groundwater tables Heavy clay soils with primary salinity, Lower Guadalquivir, Spain 10

11 Benefits of land drainage and environmental impacts Reclamation of salt affected soils, Bardenas Area, Spain Disposal of drainage effluents 11

12 Major components of a land drainage project cycle 1. Planning. LEYENDA Carretera 2. Design. Caminos Curvas de nivel Acequias 3. Construction. S 3 Dren principal (DP1 y DP2) Colectores de tubería (C1 a C7) Drenes interceptores (I1 e I2) 4. Operation and maintenance. D1 S1 D2 DP1 S2 C3 DP2 C4 C5 DP2 C6 C7 I2 Desagües en zanja abierta (D1 y D2) Drenes laterales Salidas del sistema por gravedad con compuertas (S1 y S2) Estación de bombeo (S3) 5. Evaluation of performance. I1 DP1 C2 C1 C2 C1 Castelló de Ampurias 0 500m ESCALA GRAFICA Figura 19. Esquema simplificado del trazado del sistema de drenaje propuesto para la margen izquierda del Sector IV de la Zona Regable del Muga, Gerona 12

13 1a Planning of land drainage systems 0,5 m t t'+ll D t B FAO Irrigation and Drainage Paper 62 Guidelines and computer programs for the planning and design of land drainage systems Symbol Castelló de Ampurias Land form Soil texture K (variation) (m/d) Ploughing layer Subsoil Impervious layer Depth (m) Texture Depth groundwater level (m) Hydrological conditions Land use Need for subsurface drainage L (m) Z (m) Need for surface drainage B t D Flood plain levee Flood plain transition Flood plain backswamp Estuarine plain Silt -loam Sand, Sand-loam Silt, Clay 2.5 ( ) 2.3 ( ) 1.4 ( ) 1.6 ( ) > Loam, Loamsand Sandloam Claysilt Claysilt Claysilt, pseudogley Claysilt, gley Claysilt, gley Claysilt, > ( ) 0.5 ( ) 1.1 ( ) Recharge area Transmission area Discharge area Transmission area Arable land Arable land Grassland Arable land Land smoothing + outle ts to open d itches -

14 1b Planning of land drainage systems 1st step for a socio-economic evaluation: mapping the salt- affected lands by using remote sensing techniques and field work 14

15 2 Design of land drainage systems Camino rural Colector secundario Colector primario Dren principal Tubería de riego Canal de riego Dique con camino y dren interceptor Parcela con sistemas de drenaje superficial y subterráneo Estación de bombeo de agua de drenaje con compuerta de marea Estación de bombeo de agua de riego FAO Irrigation and Drainage Paper 62 Guidelines and computer programs for the planning and design of land drainage systems 15

16 3a Construction of land drainage systems FAO Irrigation and Drainage Paper 60 Materials for subsurface land drainage systems 16

17 3b Construction of land drainage systems ILRI Publication 60 Subsurface Drainage Practices; Guidelines for the implementation, operation and maintenance of subsurface pipe drainage systems, Alterra, ILRI, Wageningen, The Netherlands,

18 4a Operation and maintenance ILRI Publication 60 Subsurface Drainage Practices; Guidelines for the implementation, operation and maintenance of subsurface pipe drainage systems, Alterra, ILRI, Wageningen, The Netherlands,

19 4b Operation of drainage systems FAO Irrigation and Drainage Paper 61 Agricultural drainage water management in arid and semi-arid areas, Rome,

20 5 Evaluation of the performance of land drainage systems Guidelines for the evaluation of the technical, economic and environmental performance of drainage systems (in preparation) 20

21 Conclusions Irrigated agriculture is essential for agricultural production. Increasing the land and water productivity in existing irrigated lands is a priority. In arid and semi-arid zones, one problem associated to irrigated agriculture is soil salinity. Land drainage is a key aspect to control waterlogging and soil salinity. Relevant innovations in the major components of the land drainage project cycle have developed during the past decade. Some developments due to FAO and Alterra-ILRI were highlighted in this presentation. 21

22 CEDEX International Course on Irrigation and Drainage Engineering PROGRAMA: Fundamentos de clima, hidrología, suelos y cultivos relacionados con el regadío Recursos hídricos para riego Viaje de estudios a regadíos de la cuenca del Ebro Redes de conducción y distribución del agua de riego Sistemas de riego parcelario Drenaje de tierras regables y control de la salinidad de los suelos regables Modernización de regadíos existentes Planificación de una nueva zona regable Operación y mantenimiento de zonas regables Planificación de regadíos a escala nacional, regional y de cuenca hidrográfica 22

23 References tm -publicaties/ ml 23

Alternatives in water resources management in Marina Baja district (Alicante province, Spain)

Alternatives in water resources management in Marina Baja district (Alicante province, Spain) S. Castaño, J.M. Murillo, L. Rodríguez Hernández Instituto Geológico y Minero de España, Spain Diputación Provincial