BAIX TER (SPAIN)
The Baix Ter irrigation district is located in the North-East of Spain. With a Mediterranean climate, it conforms an alluvial plain with Xerofluvents soils that represents the main agricultural area of the internal basins of Catalonia region. Rice production in the Baix Ter area occupies only around 1,200 ha but constitutes an agro-ecosystem with a particular social, economic and environmental strategic importance.
Intensified rice production requires a significant volume of irrigation water (to fulfill plant needs and to leach the salts), fertilizers and agrochemicals in order to reach the necessary productivity levels necessary to ensure economic viability of producers.
The critical points related to the water resources management in the Baix Ter irrigation district where the case study of rice-growing area is located are:
- Strong competition for water use. Additionally to the water use for agriculture, it must be considered the huge amount of water transferred from the Ter River towards Barcelona metropolitan area for urban and industrial uses, which currently represents 70% of the Ter River flow-rate and would have priority in case of restrictions.
- Risk of contravening the limits set by the EU Water Framework Directive due to the area is located over the Baix Ter aquifer (extension of 165 km2) and presents high concentrations of chlorides, nitrates and sulfates in specific locations. There are also reductions in groundwater levels in different locations and risk of seawater intrusion in the coastal area.
- High environmental and landscape importance, both for touristic interests of the area and to be included in the Montgrí, Illes Medes and Baix Ter Natural Park, considered an area of special environmental protection by the Autonomous Government of Catalonia. The landscape value of the environment where the rice fields are established, including the rice fields themselves, are a clear attractive along with the water birds and the biodiversity.
The main objectives of the case study are:
- to achieve high yields to ensure economic returns
- to protect natural resources.
Both objectives can be reduced to a single one: to ensure sustainability in a broad sense.
The case study involves 3 approaches:
- Field plot scale. To study alternative irrigation practices and traditional ones, irrigation technologies will be analyzed in plots of about 1 ha/plot: continuous flooding, which will act as control for comparisons and subsurface drip irrigation
- Farm scale. The selected farm (Mas Pla, 130 ha) constitutes an economic functional unity and very adequate for the study of water and rice relationships in traditional irrigation system (continuous flooding). Current studies will allow to know the evolution of the water, salts and nitrate balances and to analyze the possibilities of reuse drainage water
- District scale. The potential application of the results obtained at farm scale will be assessed at district level to know the potential effects that would cause the widespread adoption of the proposed improvements in water management.