General
National Id
Spain_03
Site name
Segovia province, left bank of Voltoya and Eresma Rivers.
Summary
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
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
NUTS Code
Castilla y León
RBD code
ES020
Transboundary
0
Data provider
Estefanía Ibáñez (IMDEA Water) in close cooperation with Enrique Fernández Escalante (TRAGSA-SEPI) whose valuable contribution is acknowledged and very much appreciated.
Source(s)
NWRM(s) implemented in the case study
Longitude
-4.572
Latitude
41.1445
Site information
Climate zone
cool temperate moist
Mean rainfall
460,709991455078
Mean rainfall unit
mm/year
Average temperature
11,1599998474121
Mean evaportranspiration
378,779998779297
Mean evaportranspiration unit
mm/year
Type
Actual Test Site
Light or indepth?
Light
Water quality inflow unit
mg/L
Average slope range
0-1%
Monitoring maintenance
Monitoring impacts effects
1
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
Performance impact estimation method
Laboratory
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
Design & implementations
Application scale
Plot
Installation date
2002
Age
12
Performance timescale
< 1 year
Area (ha)
4800
Area subject to Land use change or Management/Practice change (ha)
7,55819988250732
Size
27960
Size unit
m2
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
Peak flow (for a return period of 500 years) = 560 m3/s
Constraints
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.
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).
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
0,379999995231628
Inflow volume unit
m3/sec
Design contractual arrangement
| Arrangement type | Responsibility | Role | Comments | Name |
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Design consultation activity
| Activity stage | Key issues | Name | Comments |
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Design land use change
| Land use change type |
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Design authority
| Authority type | Role | Responsibility | Name | Comments | |
|---|---|---|---|---|---|
Lessons, risks, implications...
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.
- 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 | |
|---|---|---|---|
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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. |
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Public participation
|
secondary factor
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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. |
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Successful coordination between authorities
|
secondary factor
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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. |
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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
| Financing type | Comments | |
|---|---|---|
|
National funds
|
The Ministry of Agriculture, Food and Environmental Affairs.
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Sub-national funds
|
Castilla y León Regional Government (Agriculture and Livestock Office)
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Other
|
European Agricultural Guarantee Fund
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Other
|
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
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Driver
| Driver type | Driver role | Comments | |
|---|---|---|---|
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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.
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Public pressure
|
main driver
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Organisation committed to it
|
secondary driver
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Financing share
| Financing share type | Share | Comments |
|---|
Policy, general governance and design targets
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
0
Policy target
| Target purpose | |
|---|---|
|
Groundwater Recharge
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Increase Water Storage
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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 |
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Policy requirement directive
| Requirement directive | Specification |
|---|
Socio-economic
Costs investment information
See total cost
Costs operation maintenance
3000
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
4608946
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)
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
1
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.
Biophysical impacts
Retained water
2555000
Retained water unit
m3/year
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
1,23000001907349
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.
