DEMO Site 3: Arenales, Segovia, and Valladolid, Castile and Leon, Spain
|TDO determinations along Santiuste MAR west channel (Arenales aquifer)||Gomezserracín MAR infiltration pond at Carracillo region (Arenales aquifer)|
Since the mid-20th century the expansion of irrigation from "Los Arenales" aquifer, located in Castilla y Leon, Spain, has led to a decline in groundwater level of more than 20 m. The Aeolian sand aquifer, with an area of 1500 km2 and thickness up to 55 m is also very vulnerable to drought. In order to mitigate this impact, the Spanish Ministry of Agriculture (MAPA) developed MAR facilities in three pilot zones. The project, building works, tracking and further monitoring was entrusted to Tragsa Group. These were accompanied by improvements in water management, based on the organization of communities of irrigation farmers, exchanges of arable land, change in crops, improved efficiency of irrigation, extension of the energy supply net, and reduction of energy consumption. Also there was recovery of environmental features such as degraded wetlands (La Iglesia and El Señor lagoons), springs that had dried, dilution of nitrates and of other pollution vectors, etc.
At the Santiuste basin site, river water was diverted for recharge by gravitational flow through 18 km of buried pipes to the recharge facilities; including infiltration ponds, artificial wetlands, canals and large diameter wells. Researchers also successfully tested buried filter pipes and drainage ditches. Once constructed and commissioned, the works were transferred to the communities of irrigators, who are responsible for the management and maintenance, under the advice of specialists of the Duero Hydrographic Confederation (CHD) and Tragsa. Due to variable river flows annual volumes recharged in the two main pilots ranged between 0.5 and 12.2 Mm3 (Santiuste basin) and between 0.5 and 5.5 Mm3 (Carracillo council) between 2002 and 2008. The river water was supplemented by 0.5 Mm3/yr of treated sewage effluent since 2005. MAR facilities currently operative at the demonstration site are:
- Length of infiltration canal: 27 km
- Infiltration ponds: 5
- Artificial wetlands: 1
- Open infiltration wells: 3
- River bank filtration for municipalities supply: 1
- Ridges/soil and aquifer treatment techniques: 1
- Accidental recharge by irrigation return
- Length of infiltration canal: 40,7 km
- Infiltration ponds: 3
- Artificial wetland: 1
- Infiltration field (flood and controlled spreading): 1
- River bank filtration scheme for irrigation: 1
- Broad accidental recharge by irrigation return
- Interdune filtration ditches
Initially some farmers resisted the new organizational structures and this was resolved through negotiation and informing the respective communities on sustainable development, environmental awareness and hydrogeological processes including the applications of MAR. Subsequently there has been an unintended increase of about 15% in the irrigated area due to what has been called "contagious effect", of a decline in the price of water, and in the costs of pumping. Organizational change has motivated a substantial environmental improvement, providing a basis for resolving emerging issues. Incipient economic resurgence is observed in these rural areas that had previously been depressed. Of concern is the growing demand for irrigation water in areas that are not so feasible for MAR. It is also worth mentioning that there are plenty of industries and SMEs depending on the aquifer storage apart from the agro-industry.
The proposed activities in the large-scale demonstration sites managed by Tragsa are:
- Water and energy management improvements. By means of public participation and a deeper education of the farmers groups involved in the irrigators communities, plus a permanent modernization. The examples of success are quickly shared among the commoners.
- Initial MAR devices and further improvements. The initial design for MAR devices was based on the expertise of Tragsa Group. Since 2002 an important effort has been dedicated in more efficient devices. This improvement in the state-of-the art for building work companies has been the biggest target of the DINA-MAR project (www.dina-mar.es). There are advances on ditches and canals slopes, infiltration ponds morphology, actions in their bottom (furrows design), changes in the design of existing infiltration wells, most suitable water pre-treatment standard studies, gravel filters, etc. Most of the prototypes installed must be improved and updated, what represents a permanent task.
- SAT-MAR. Waste water treated by a lagooning process is being used to recharge the aquifer. New prototypes should be tested to enhance waste water purification.
- Industry mobilizing. Thanks to MAR activities, apart from farming, some agro-industrial activity is being developed in these areas, specially related to packaging of vegetables and exportation of first quality crops. Municipalities play also an important role in MAR management, and Public Private Partnership (PPP) schemes are being implemented from the very beginning.
- Artificial wetlands. There are two wetland pilot sites within the large-scale demonstration site. Both artificial wetlands were constructed by Tragsa.
- Ecosystems. There is an interesting experience on the recovery of a degraded lagoon by means of MAR. It is a unique experience in Spain and again pilots are being tested to modify MAR water to achieve a quality as of before the degradation impacts. Also the use of biominerals and salt deposits is studied in this context.
- Public Private Partnership. This experience is a significant example of how public activities have been able to involve public participation, first as the trigger that stimulates the construction of MAR facilities by the Spanish Government, and importantly as water users increase their productivity and water management efficiency.
- Decision Support Systems. The integration of recharge enhancement with demand management is demonstrated. There is also a new shared perspective of the aquifer as both, an irrigation and industry depending on the aquifer resource and sustaining the environment.
There are still many gaps to solve and research to be done to mobilize industry and SMEs in this area, especially related to vegetables packing and exportation. Most of the older networks for monitoring are being wasted due to economic crisis, and the materials broken could not have been replaced by now. There has not been any budget to improve the materials and data-collection stations already deployed. At the demonstration sites, apart from recovering the monitoring systems and inoperative sensors, it is expected to achieve new results and developments such as, for example, flow meters and specific pilots to test and validate building works designs, in order to achieve the biggest infiltration rate plus successful and long life operability.
Aquifer Recharge as a
Solution to Water Scarcity
An EU FP7 Project
Coordination & Contact:
Prof. Dr. Christoph Schüth
Darmstadt Technical University
Institute of Applied Geosciences
The MARSOL project receives funding from the European Union's Seventh Framework Programme for Research, Technological Development and Demonstration under grant agreement no 619120.
This project website reflects only the authors' views and the European Union is not liable for any use that may be made of the information contained therein.