Implications of Different Management Scenarios on Sustainability. The Case of Tablas de Daimiel National Park

A. De la Hera1, E. López-Gunn2, R.M.Stephan3

 

1 Instituto Geológico y Minero de España (IGME). Ríos Rosas 23. 28003 Madrid; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2 ICATALIST and Cheney Fellow, University of Leeds; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

3 Water law expert. International consultant; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

Abstract

The Tablas de Daimiel are a paradigmatic case in SW Europe, not only because of its status as a protected zone under international, European and national legislation, but also by the different governance initiatives designed and implemented to stabilize intensive groundwater use since the 70s. This paper presents an analysis of this historical evolution, including physical, legal and socio-economic aspects, aimed at extracting lessons learned. The approach is eminently hydrogeological, considering the operation of the system in the four phases to analyze its evolution: before the 1960s, corresponding to its operation under undisturbed conditions; between 1960 and 1983, a period of disturbed functioning of the aquifer; between 1984 and 2012, corresponding to an inverted relationship in the functioning of aquifer-wetlands; and after 2012 to the present, described by some authors as potentially as of "irreversible" damage to the wetland and in which flow models predicted a start to the improvement of levels in the aquifer in no less than five years period, if pumping was stopped under the best scenario.

Keywords: groundwater, management, Tablas de Daimiel, sustainability, Mancha Occidental.

 

Introduction

The protection of groundwater dependent ecosystems has been promoted by the Water Framework Directive and its transposition into national policies. In Spain, the Tablas de Damiel are the last remnant of a type wetlands known as river tables, representing the southernmost example in Europe. It is located in the region of Castilla-La Mancha (Figure 1), in the Upper Guadiana river basin. The Upper Guadiana river basin is defined by the waters drained by this river to the reservoir called El Vicario, downstream of the Tablas de Daimiel. The whole area of this basin is occupied by aquifers that constitute groundwater bodies.

From a geological point of view, the Upper Guadiana basin is located in the Tertiary corridor of the Mancha plain, a plain of approximately 240 km by 50 km, direction E-W, between the basins of the Guadiana and Júcar rivers, formed by a continental detrital and carbonated filling more than 200m thick (Mejías-Moreno, 2014). This plain borders to the north with the Sierra de Altomira and with the Intermediate Depression and El Campo de Montiel to the south. Also with the Toledo mountain range and Campo de Calatrava to the west and the Mancha Oriental to the east. This Tertiary corridor of the Mancha plain constitutes precisely the Mancha Occidental aquifer, consisting of three groundwater bodies (Mancha Occidental I, II and Rus-Valdelobos). Because of the status of surface and groundwater in the Guadiana Upper basin, the Mancha Occidental river basin agency ruled in 2014 at risk status in both qualitative and quantitative the three groundwater bodies (BOE, 2014a).

 

Fig01
Figure 1: Location of groundwater bodies, Tablas de Daimiel wetland and recharge wells in the Upper basin of the Guadiana river.

 

Tablas de Daimiel are a paradigmatic case in SW Europe, not only because of its status as a protected zone under international, European and national legislation, but also due to repeated governance attempts designed and implemented to stabilize intensive groundwater use since the 70's. The Tablas de Daimiel is protected at international, European and national levels.

Even before the 50s, the area was subjected to various drainage attempts and subsequently has been in constant conflict with the intensive exploitation of groundwater in what is predominantly an agricultural region. The history of the region has also gone through a sequence of regional policies aimed first at the transformation of rain fed to irrigated agriculture, and more recently to a more sustainable groundwater use, following the dramatic situation around the year 1992, and the consequent demands of the European Commission. This was due to the breach of the Habitats Directive as a Site of Community Interest, together with complaints from environmental groups to UNESCO.

This paper presents an analysis of this historical evolution, including physical, legal and socio-economic aspects, aimed at extracting lessons learned. The approach is eminently hydrogeological, considering the operation of the system in the four phases to analyse its evolution according to periods indicated in Figure 2: before the 1960s, corresponding to its operation under undisturbed conditions; between 1960 and 1983, a period of disturbed functioning of the aquifer; between 1984 and 2012, corresponding to an inverted relationship in the functioning of aquifer-wetlands; and after 2012 to the present, described by some authors as potentially as of "irreversible" damage to the wetland and in which flow models predicted a start to the improvement of levels in the aquifer in no less than five years period, if pumping was stopped under the best scenario.

 

Fig02
Figure 2: 41 years of yearly groundwater variations (1975-2016) in one piezometer located in Villarta de San Juan, upstream and close to Tablas de Daimiel. Three time periods of groundwater management are indicated and illustrated according to the interactions between the Tablas de Daimiel wetlands and Mancha Occidental aquifer: 1960-1983 Tablas de Daimiel was functioning as a discharge wetland although under perturbed conditions. Between 1983 and 2012 it was functioning as a recharge wetland showing an invested functioning of the system. Finally, between 2012 and present, in undefined situation which needs to be clarify according to new data not yet available. Continuous lines in the figures which illustrate each time period indicate lines of equal hydraulic head; dashed lines in the same figures illustrate the direction of groundwater flow.

 

Before 1960

This period represents the state of undisturbed aquifer for the Western Mancha. In these years, groundwater use was limited to the existence of traditional water wheels to irrigate small vegetable gardens. Land management carried out by the Government promoted the draining of marshes to win them for cultivation. Already in 1980, the Cambó Act came into force, which included wetland desiccation. Later, in 1956, a second law came into force with the same objective, the "Law of Sanitation and colonization of the marshlands" that covered the immediate margins of the Guadiana, Cigüela, Záncara rivers and their tributaries in the provinces of Ciudad Real, Toledo and Cuenca).

 

Period 1960 to 1983

This period represents the years of operation of the disturbed aquifer: as a result of the gradual increase in pumping, the water table started to drop progressively.

In this period drainage and channeling schemes continued to reduce the wetland area. This is although, already in 1963, the Tablas de Damiel were already identified as a preferential wetland area in the European continent. In 1966 the Peñarroya Reservoir began operating, with about 7,000 hectares now irrigated with surface water within the Mancha Occidental. In the same year, Law 37/1966 of 31st May, created the National Game Reserve of Tablas de Daimiel. However, this not only did not stop its desiccation, but furthermore it promoted its unsustainable use from the biodiversity point of view (Mejías-Moreno, 2014).

Around Tablas de Daimiel, the construction of irrigation wells was increasing progressively, a process called a "silent revolution" by some authors (Llamas et al. 2006). To alleviate the various threats, the Tablas de Daimiel were declared a National Park in 1973 (under Royal Decree 1874/1973 of 28th June).

By 1978 the Tajo-Segura water transfer becomes operational, which allowed to take water from the first to the second basin with an authorized volume of 600 million m3/year.

The Mancha Húmeda Biosphere Reserve is designated in 1981 by UNESCO, with a maximum of 25,000 ha, composed of a central core area where the Tablas de Damiel are located, and a buffer and peripheral areas, where more than one hundred wetlands are distributed. In 2014 this area was increased to 418.087 ha (BOE, 2014b).

Two years later, in 1982, the wetland was recognized as a wetland of international importance under the Ramsar Convention.

The contribution based on groundwater flow models by the Guadiana river in the Ojos del Guadiana was estimated at 90-120 million m3/year, after its entry to the Tablas de Daimiel (including a contribution of 15-25 mm3/year from the Azuer river) (Martínez-Cortina, 2001).

All these designations however fail to prevent the aquifer situation, due to increased extraction groundwater, which causes the decline in the water table. In 1983 the Ojos del Guadiana spring dried up, not to flow again till many years later, when the confluence of a number of factors, namely mitigating management measures and favourable weather conditions allowed the spring to flow again, going against what some authors had considered as "irreversible".

 

Period 1984 to 2012

This period represents the reverse operation of the aquifer, i.e., what once were discharge areas under natural conditions became recharge areas. This meant significant changes in the water balance components: outputs from evapotranspiration disappeared, thus increasing renewable resource by around 50% (Martínez-Cortina, 2001; Martínez-Cortina et al. 2011).

The twenty-year period from 1970 to 1990 was the peak for the groundwater pumping in the aquifer of the Western Mancha. Around 140,000 ha were converted to irrigation in the land covered by the aquifer.

In 1985 the reform of the Water Act represented a radical change in the management of groundwater when groundwater became a public resource. The Guadiana river basin agency was responsible for management within the Upper Guadiana basin with the launch of two management instruments: the registry and groundwater catalogue, which coincided with the appearance of the first illegal wells (Fornés et al. 2007). It was estimated that 20% of all the agricultural land is irrigated illegally, equivalent to 30,000 ha.

Since 1987, a variety of measures management plans and laws have been implemented, including the Water Framework Directive (Rodriguez-Cabellos, 2014). In 1987 the Water Regeneration Plan of the Tablas de Daimiel National Park was approved. The Law 13/1987 of July 17 authorized the Ministry of Public Works to divert water from the Upper Tagus basin, through the Tajo-Segura on a trial basis, to the Tablas de Daimiel National Park. The first transfer took place in 1988 and to date there have been made a total of 15 transfers, the last between 4th and 30th January 2010, with variable efficiency, depending on the climatic and physical riverbed conditions. In the same year of 1988, the Tablas de Daimiel was declared an SPA (Special Protection Area) under to Birds Directive 79/409/EEC, now Directive 2009/147/EC, supplemented by Directive 92/43 / EEC.

The year 1989 was the deadline to register exploitations since the Groundwater Registry was being closed.

In 1992 Tablas de Daimiel was designated as an SCI (Site of Community Interest) integrated in the Natura 2000 network under the Habitats Directive.

Between 1985 and 2013, the Common Agricultural Policy (CAP) was operational. During this period a number of events took place: (1) in 1987 the aquifer of the Mancha Occidental was declared provisionally overexploited, with the entry into operation of extractions plans, and a ban on drilling new wells; and (2) the historical pumping peak was reached, when 570 mm3 were abstracted. (3) In 1990, in a marked dry climactic sequence, the Tablas de Daimiel suffered its greatest reduction in flooded area, decreasing to 75 ha (from 2000 ha). As a consequence, a spontaneous peat combustion occurred in the Guadiana valley, and associated with these fires, the collapse of terrain and toxic gas emissions.

In 1993 a reform of the CAP took place, towards maintenance oriented farming and greater consideration for the environment. However, these measures did not have consequences on the state of the aquifer, and in 1994 the aquifer was declared finally overexploited, which involved the creation of user communities and the issuing of extractions management plans by the Guadiana river basin agency.

Between 1993 and 2007 an Income Compensation Plan was introduced with grants for farmers to undertake voluntary water savings.

Between 1995/96 and 1997/98 there was a period with heavy rainfall (with an average annual rainfall of 540 mm/year), which put an end to the long dry sequence, and that in some areas meant a recovery of up to 15m in aquifer levels.

In the years 1997 and 2000 the Guadiana river basin agency opened a series of wells for artificial recharge, a number that was increased in 2010. These wells were strategically placed between Tomelloso and Villarta de San Juan, in the so-called Canal del Guadiana, to collect surpluses from the Peñarroya Reservoir. Currently there are 25 to 30 wells.

Both Martínez-Cortina (2001) and Martínez-Santos (2007) developed flow models for the study area, the first for the whole Upper Guadiana basin, and the second for the Mancha Occidental aquifer. The simulation scenarios analysed predicted a recovery on aquifer levels in the Mancha Occidental in less than five years, considering various weather and groundwater operating conditions. Martínez-Cortina (2001) suggested that the recovery of the aquifer was plausible in around five years under an extreme hypothesis of both a complete absence of extractions and a wet weather sequence. Facts have shown that the maintenance of pumping in moderate extractions, together with a wet sequence can recover the system, together with complementary measures such as the contributions from 2008 from artificial recharge wells.

In 2001 the groundwater catalogue was closed, which represented the deadline to register private wells drilled before 1986.

In the same year, 2001, the Law on the National Hydrological Plan was approved. Here the Parliament requested the development of a Special Plan for the Upper Guadiana (SPUG). One of the measures envisaged included the construction of a battery of artificial recharge wells along 35 km of the Guadiana channel. This plan was executed between 2008 and 2013 while budgets allowed.

A few years later, the situation remains unimproved in the Tablas de Daimiel National Park. In 2007 conservation groups sent a complaint to UNESCO proposing the withdrawal of the Mancha Húmeda from the Biosphere Reserve Network.

In 2009 a peatlands fire generated media attention. The Tablas de Daimiel National Park had been dry since 2005 due to a new drought episode. Under natural conditions in a saturated state, peat retains CO2. However in unsaturated conditions, like the drought experienced in the Tablas de Daimiel, peat loses water and gets cracked. The air begins to flow through the holes and oxidize the peat, which begins to heat up. From a certain temperature, peatlands combust, burning slowly, without a flame, releasing CO2 into the atmosphere.

In 2010 the European Commission notified Spain of a breach in its obligations under Directive 92/43 /EEC (Habitats Directive), which meant Spain must issue bi-monthly reports informing the EC on the status of the Tablas de Daimiel National Park until 2016.

Between 2009-2011 an episode of heavy rains occurred again that could recover aquifer levels in half the time than in the years 1996-1998. The recovery was estimated in the order of 1,930 mm3 (Mejías-Moreno et al. 2012).

 

Period 2013 to the Present

This period represents a stage of apparent quantitative recovery in the aquifer, with a continued recovery of aquifer levels. As a result, the hydraulic gradient has reduced with seepage from the river bed, allowing water to reach the Tablas de Daimiel National Park. However, this aquifer recovery is attributed to a cyclical event, which coincides in time with the maintenance of some recharge, as a result of i) the last wet period, ii) decreased pumping, iii) the implementation of measures for more efficient management by the Guadiana river basin agency and iv) savings in groundwater use.

In the 90s, the worst years for the evolution of the aquifer, the emptying was estimated at 3,750 million m3/ year, while it is currently estimated at around 350 million m3/ year (ten times lower) (Mejías-Moreno, 2014).

The last three decades have witnessed wet and dry periods that have occurred in parallel to ongoing conflicts and negotiations among the main users for water - irrigation farmers- and the water authorities (Rodríguez-Cabellos, 2014).

In 2014 the limits of the Tablas de Daimiel National Park were extended by purchasing adjoining properties and associated water rights. In the same year, the Upper Guadiana basin water bodies were declared at risk.

In 2015 the Government of Castilla-La Mancha considered that it had remedied the deficiencies that generated the complaint to the EC. In 2016 the first draft of the Plan for Management and Regulating Use in the Tablas de Daimiel National Park has been presented. Its objectives relate to the conservation of the park's resources, its public use, research, the relationship with the environment and social participation, monitoring and management of the area, and coordination and collaboration between institutions.

 

Discussion

Tablas de Daimiel constitutes a protected natural area in a region where agricultural policies, applied at first detached from water management caused a significant deterioration to the ecosystem, later the importance of an approach that takes this into account has gradually emerged. The facts described show a need to:

  1. involve all users to achieve common environmental objectives.
  2. work in a coordinated manner by all administrations.
  3. implement measures that do not harm the ecosystem.

The changes in the functioning of the Tablas de Daimiel, both in the quality and quantity of water that feeds the wetland will not allow the system to recover to its original (undisturbed) situation. An indicator on the ecosystem health is the presence of Claudium mariscus. Before 1960 the area covered was estimated at 57% of the surface in the Tablas de Daimiel, whereas by 2007 the area was estimated at 6%. This change in vegetation has led to changes in the food chain, which are manifested in the ecosystem flora and fauna (disappearance of ducks, appearance of tents). A very considerable change was observed in the emergent vegetation that affects the health of the system.

As for the quality of groundwater, the use of agricultural fertilizers around the Tablas de Daimiel for decades, has led to increased levels of nitrates and phosphates in the water that feeds the wetland, increasing the eutrophication levels.

 

Conclusions

The consequences of the different management scenarios described allow drawing some conclusions regarding the legal-administrative, political, ecological, and environmental aspects. Among the main lessons learned we may include the following: (1) the solutions to these real problems must be addressed from a multidisciplinary approach and must be implemented within the framework of long-term integrated and planned political action, not subject to political four-year term programs. (2) The coordination and communication among institutions involved in land management is essential to succeed in planning objectives. (3) The recovery of the Mancha Occidental hydrological aquifer system has taken place gradually, as the abstractions were reduced, the launching of artificial recharge wells and above all, some wet sequence periods. (4) The Upper Guadiana basin needs a steady control on groundwater withdrawals, especially during dry years. (5) The involvement of users in the management of groundwater is key to achieving aquifer management objectives and to achieve good practice. (6) Environmental education is an essential tool for future generations to learn to value and appreciate the natural heritage relevant not only for Spanish society, but also at the international level.

 

References

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