Managed Aquifer Recharge in Los Arenales (Segovia, Spain)

National Id
Site name
Segovia province, left bank of Voltoya and Eresma Rivers.
Managed Aquifer Recharge in Los Arenales (Segovia, Spain).
As showed by data obtained after 8 effective recharge cycles carried out in an experimental area (Cubeta de San Tiuste) at Los Arenales Aquifer (Segovia, Duero River Basin, Spain), Managed Aquifer Recharge can be more than an effective measure for storing large quantities of water in underground aquifers to naturally increase the quantity of groundwater in times of shortage: it can also result in an enhanced natural condition of aquifers and water availability. Also, the natural cleaning process of water percolating through the soils when entering the AGR showed its potential for providing improved water quality
Castilla y León
RBD code
Data provider
Estefanía Ibáñez (IMDEA Water) in close cooperation with Enrique Fernández Escalante (TRAGSA-SEPI) whose valuable contribution is acknowledged and very much appreciated.
NWRM(s) implemented in the case study
Climate zone
cool temperate moist
Mean rainfall
Mean rainfall unit
Average temperature
Mean evaportranspiration
Mean evaportranspiration unit
Actual Test Site
Light or indepth?
Water quality inflow unit
Average slope range
Monitoring impacts effects
Monitoring location
Catchment outlet
Monitoring upstream station
Dina-Mar ZNS-1 (Sig-Pac plot 40:221:0:0:1:6244; Coord 369694:4557512)
Monitoring downstream station
Dina-Mar ZNS-2 (Sig-Pac plot 40:65:265:0:7:5372:2; Coord 369246:4561559)
Performance impact estimation method
Performance impact estimation information
Changes in water table have been studied with the Water Table Fluctiation Method (Healy and Cook, 2002). Studies of the non-saturated zone were carried out with control stations, which measured humidity, temperature and pressure (or tension). The latest monitoring technique is the use of a thermal camera to study the evolution of silting
Application scale
Installation date
Performance timescale
< 1 year
Area (ha)
Area subject to Land use change or Management/Practice change (ha)
Size unit
Design capacity description
The system was designed for a maximum water flow of 1000 l/s (or 1 m3/s) and a maximum annual volume of 8 hm3.
Basis of design
Peak flow (for a standard return period of 5 years) = 100 m3/s
Peak flow (for a return period of 500 years) = 560 m3/s
In winter, water freezing reduce infiltration to the aquifer. This might be relevant considering that the concesion of water for this propose goes from November to April.
Some years have not been successful due to silting up in soakways and pond.
The water transfer from Voltoya River to the recharge channel needed to be stopped during heavy rain days in order to avoid flooding.
Additionally, the Lisse effect (excess of air trapped in to the aquifer reduces the infiltration capacity) has been a problem during the implementation, having to modify the design and structure of the devices.
Erotion of soakways/channels banksides, jeopardising stability.
The transfer of water to the recharge system was only allowed is the flow in Voltoya river was be above 600 l/s (in order to guarantee the ecological flow.
Favourable preconditions
The channel was designed to take advantage of the former route of the Ermita strem to enhance infiltration.

Essays and monitoring in the site of study showed that in areas were the aquifer was more than 3m deep, infiltration was more effective.

Literature lists favourable conditions for aquifer recharge: scant vegetation, permeable or fractured soil, high water table level, and aboundant rainfal (De Vries and Simmers, 2002).
Inflow volume
Inflow volume unit
Design contractual arrangement
Arrangement type Responsibility Role Comments Name
Design consultation activity
Activity stage Key issues Name Comments
Design land use change
Land use change type
Design authority
Authority type Role Responsibility Name Comments
Initiation of the measure
Ministry of Agriculture, Food and Enviromental Affairs, Spain
The ministry responsible for environmental affairs.
Initiation of the measure
Castilla y Leí³n Regional Government (Agriculture and Livestock Office)
Is the regional authority for agricultural affairs.
Type: Public Company
Role: Tragsa has been involved since the begining is most of the stages: Initiation of the measure; Determination of design details of the measure, Implementation, Financing (from 2007 to 2010) and Monitoring.
Local water authority
Duero River Basin Authority
Supporting tragsa withdata collection and providing information.
Universidad Complutense de Madrid
Type: education and research institution
Role: monitoring and field research
Irrigators Community
Framers were actually involved in all the process. They were responsible for opening and closing the recharge devices following Tragsa instructions.
Key lessons
- It is important to involve irrigators in the process and the implementation of measures, especially to those Communities that use underground waters, since the withdrawal control is lower than for those using surface waters.
- It is important to improve economic and geopolitical indicators, apart from the hydrogeological ones, prior to the implementation of new devices.
- Monitoring is key to improve effectiveness, to improve the devices and to increase infiltration rates and the total volume infiltrated to the aquifer.
- Some key actions to ensure the proper functioning of the measure is the pre-treatment of water, the inflow regulation, reduction of suspended soils and air in water. Is advisable to avoid whipping of recharge water. Low flow speed is preferred.
- Some of the most common limitations are soil silting and increase of trapped air in the aquifer, which can be avoided with SAT techniques and the proper design of the channel.
Success factor(s)
Success factor type Success factor role Comments
Attitude of relevant stakeholders
main factor

Once the infiltration system started working, it was necessary the participation of the irrigator community to manage the entrance of water from Voltoya River. This procedure proved to be the most efficient to avoid excess of water and flooding in nearby areas, or to surpass the limit established by the River Basin Authority of 8,5hm3 to be used for recharge purposes. Mayors of related towns were always collaborative.

Public participation
secondary factor
Attitude of decision makers
secondary factor

Once the overexploitation problem was identified, local and national authorities reacted with a project of aquifer recharge, declaring the implementation of measures of "general interest". Mayors of related towns were always collaborative.

Successful coordination between authorities
secondary factor
Communication activities
secondary factor

The project has became a practice of interest in Spain and is often visited by students, other researcher, and even a dissemination plan has been implemented for the general public.

Existing staff and consultant knowledge
main factor

Some of the researchers involved in the project have been very committed to the continuation of monitoring and sampling to get additional data and results even when the budget was scant.

Financing type Comments
National funds
The Ministry of Agriculture, Food and Environmental Affairs.
Sub-national funds
Castilla y León Regional Government (Agriculture and Livestock Office)
European Agricultural Guarantee Fund
Trasgsa (public company) financed an RTD programme (2007-2010) to continue the research activity regarding aquifer management activities. SEPI Group (Spanish Society of Industrial Participations) was the main shareholder
Barrier type Barrier role Comments
Lacking financing sources
main barrier
The lack of financing actually became a barrier during the recharge cycles 2010/2011 and 2011/2012, when maintenance, new infraestructures and expansions were not possible, and the little activity that remained was thanks to private efforts (of researchers and irrigators)
Existing technical standards
secondary barrier
During the progress of the implementation silting was one of the major problems which reduded efective infiltration of water into the aquifer. Several studies were carried out in order to define best solutions and improve effectiveness of the measure.
Legal obligations / restrictions
secondary barrier
A "spill" authorization is needed to implement this measures in Spain (despite the fact that most activities result in an increased groundwater quality)
Driver type Driver role Comments
Balancing different objectives
main driver
A group of groundwater users posed their concern about the aquifer degradation to the local authorities, which enabled a serie of interventions.
Public pressure
main driver
Organisation committed to it
secondary driver
Financing share
Financing share type Share Comments
Policy description
The exploitation of the superficial aquifer, mainly for irrigated agriculture, has led to a 10 m fall of the water table, which has led to related salinization and pollution processes. [WFD pressure: 3.1 Abstraction, Agriculture]
Part of wider plan
Policy target
Target purpose
Groundwater Recharge
Increase Water Storage
Policy pressure
Pressure directive Relevant pressure
Policy area
Policy area type Policy area focus Name Comments
Policy impact
Impact directive Relevant impact
Policy wider plan
Wider plan type Wider plan focus Name Comments
Policy requirement directive
Requirement directive Specification
Costs investment information
See total cost
Costs operation maintenance
Costs operation maintenance
Each recharge cycle had maintenance works of the channel and basins depending on the results of the previous year. However, there is not a specific budget with details on these specific costs.
Costs total
Costs total information
Initial investmentuntil 2006:
Water intake: 409657 €
Transfer conveyance: 2641615 €
Recharge channel 1: 289940 €
Recharge channel 2: 606867 €

Investment in the second period: 660867€ (The amount was devoted to maintenance, studies and projects)
Compensations annual information
There is no specific records of compensation payments to landowners or irrigators affected by the measure. In fact, the implementation of the measure was originated from a social claim to recover a damage aquifer, and irrigators and landowners were involved in the petition.
Information on Economic costs - income loss
In very wet years, agricultural fields (generally with potato crops) have been occasionally flooded after the groundwater level reached the limit that should not be exceeded in aquifer managment and recharge practices (defined in 1.5m by Fernández Escalante, 2005).
Ecosystem improved biodiversity
Information on Ecosystem improved biodiversity
The implementation of the measures also included the restoration of La Iglesia lagoon, which has served as a refuge for bird life and as a nesting area.
Ecosystem impact climate regulation
No information available
Information on Ecosystem impact climate regulation
Not specific impacts are described in the literature on the case study.
Retained water
Retained water unit
Information on retained water
Average value per recharge cycle calculated on the basis of the data obtained after 8 effective recharge cycles. Of the total volume derived to the infiltration devices, that is the volume that was actually infiltrated into the aquifer in each of the cycles in which the measure was working. Values obtained per cycle: 1300000 m3 (cycle 1; 2002/03); 1800000 m3 (cycle 2; 2003/04); 970000 m3 (cycle 3; 2004/05); 3560000 m3 (cycle 4; 2005/06); 12190000 m3 (cycle 5; 2007/08); 460000 m3 (cycle 6); 2500000 m3 (cycle 7; 2008/09); 640000 m3 (cycle 8; 2009/10); 2130000 m3 (cycle 9; 2010/11); 0 m3 (cycle 10; 2011/12).
Information on increased water storage
For each cycle of recharge was calculated the volumen of water devoted and the actual recharged volume. The following are the percentage of used volume vs recharged volume: 37,14% (cycle 1); 80% (cycle 2); 76,98% (cycle 3); 69,67% (cycle 4); 96,13% (cycle 5); 87,41% (cycle 6); 64,50% (cycle 7); 90,46% (cycle 8); 68,03% (cycle 9); 0% (cycle 10).
Increased groundwater level
Information on Increased groundwater level
Average value per recharge cycle on the basis of the the data obtained after 10 recharge cycles (and excluding cycle 6 value -see later-). These values show the variation in the groundwater level in the monitoring network. The value of the Cycle 6 cannot be only attribuible to the recharge as there was also abundant precipitation that year, and measurement could not differ between sources. Values obtained per cycle: 2,30 m (cycle 1); 2,10 m (cycle 2); 1,17 m (cycle 3); 3,36 m (cycle 4); 0,31m (cycle 5); 3,57*m (cycle 6); 0,62 m (cycle 7); 0,41 m (cycle 8); 0,54 m (cycle 9); 0,28 m (cycle 10).
Information on Water quality overall improvements
The hydrochemical evolution of groundwater has shown improvement in nitrate concentrations (which were very high at the beginning: 274 mg/L in the NE of the aquifer). On the other hand, some negative impacts occurred like the increased concentration of diluted iron in central-eastern areas of the aquifer, the creation of a reducing environment with calcium carbonate precipitation, and formation of imprevious crust.
Soil quality overall soil improvements
Not relevant for this application
Information on Soil quality overall soil improvements
Soil is relevant for this applicationonly regarding infiltration rates. Once the recharge has began, silting is one of the major constrains in terms of infiltration reduction. This is why Soil Aquifer Tecniques are applied in the channel /soakways and in the infiltration basins.


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