Hydrogeology of Ponds, Pools, and Playa-Lakes of Southern Spain

WETLANDS, Vol. 27, No. 4, December 2007, pp. 819–830 ’ 2007, The Society of Wetland Scientists

HYDROGEOLOGY OF PONDS, POOLS, AND PLAYA-LAKES OF SOUTHERN SPAIN

Miguel Rodrı´guez-Rodrı´guez Department of Physical, Chemical, and Natural Systems University Pablo de Olavide Utrera Rd., km 1 41013 Seville, Spain E-mail: [email protected]

Abstract: I characterized 33 small water bodies from the southern Spain provinces of Seville, Cadiz, and Malaga using hydrochemistry (geochemical analyses), hydrology (water budgets), geological surveys, and local knowledge. Based on hydrogeological criteria (association with permeable materials), water bodies were grouped into three categories: 1) wetlands associated with permeable materials (playa-lakes), 2) wetlands associated with impermeable materials (ponds and pools), and 3) artificial wetlands. The three wetland typologies differed in morpho-structural indices, hydrogeological functioning, water chemistry, flora and fauna, and vulnerability to a range of human impacts, and these attributes need consideration in habitat management and conservation.

Key Words: hydrogeochemistry, hydrological functioning, semi-arid climate

INTRODUCTION cycles of drying and filling. I define ponds as areas of permanent water similar to lakes, but smaller, and Ponds and pools are generally defined as small pools as small seasonal water bodies. All of these and shallow water bodies, with the former holding wetland types are disconnected from permanent water permanently and the latter dry periodically, rivers or streams, but ponds and pools occur on less depending on precipitation (Meester et al. 2005). permeable soils with minimal interaction with the These definitions include both man-made and subsurface, whereas playas occur on more perme- natural water bodies. Playa-lakes are a type of able materials where interactions with the subsurface wetland without a universal definition (Smith 2003). (both recharge and discharge) are extensive. The Some authors consider playa-lakes as saline systems European Water Framework Directive (WFD- and define them as seasonally to perennially filled CISNu2 2002) imposes a minimum size limit of water bodies connected to a regional aquifer with 0.5 km2 (i.e., 50 ha) to define a lake. This size limit is ground-water discharge into the systems (Duffy and artificial as ponds share characteristics with lakes in Al-Hassan 1988). Similarly, other authors (Rosen terms of structure and function. There is little 1994) also postulate that playas are primarily evidence that the ecological characteristics of discharge systems, although a few can recharge the shallow lakes differ fundamentally over a size range aquifer. Some wetland scientists define these water from few to 10,000 ha (Moss et al. 2003). bodies as saline lakes (Wood et al. 1992, Hovorka Biological communities of ponds, pools, and 1997). Finally, in the U.S., most investigators define playa-lakes have been characterized and a number playas as recharge areas that seasonally pond fresh of biotic indices have been developed for these water, with the majority being located in the ecosystems (Boix et al. 2005, Della Bella 2005). Southern High Plains of Texas and New Mexico However, little is known about their hydrological (Lehman 1972, Scanlon et al. 1994, Wood and function or how they are affected by human Sanford 1995, Haukos and Smith 2003). development and management (Biggs et al. 2005). In this work, I define a playa-lake as a shallow Given the importance of small water bodies in water body without outlets and with a closed maintaining biodiversity at the landscape scale, watershed of permeable or semi-permeable materi- further research is needed on these systems and als. A playa can thus recharge the underlying aquifer their watersheds. Pond and playa-lake richness and or aquitard (freshwater playas), or can be a discharge diversity may be partially linked to watershed area of ground water (saline playas), depending on character as they are sinks for substances draining the position of the piezometric level (Eckles et al. from their catchments and typically reflect very local 2002). Playa-lakes undergo annual or multiyear natural variation in geology, hydrology, and plant

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considerable. The climate is characterized by dry, hot summers, and mild, winter temperatures with irregular precipitation, most of it occurring from October to February. In western Andalusia, mean precipitation ranges from 500–600 mm/year at an altitude of 0–400 m ASL, whereas in high mountain areas mean annual precipitation can exceed 1,000 mm/year (Benavente et al. 2006a, b). This area has historically been cultivated for dry land cereal and olive-tree farming with intensive irrigation occurring whenever water resources are nearby. In recent years, an increase in irrigation has occurred. In higher areas, scrub or Mediterranean woodland predominates. The lithology of the region is patchy and influences characteristics of wetland watersheds and their typologies. A variety of soils with different run-off properties and permeability occur (Vanderlinden et al. 2005). Topography is Figure 1. Locations of 33 water bodies studied: A) variable, with moderately high mountain ridges General location (L.O. 5 Lantejuela-Osuna aquifer; F.P. adjacent to faulted basins. 5 Fuente de Piedra aquifer; C. 5 Campillos aquifer; L. 5 Lebrija aquifer), and B) Geological sketch. Geologically, the study area is located in the western part of the Betic Cordillera (Figure 1B). communities. Small water bodies are often threat- Sedimentation in the Betic Cordillera took place ened by drainage and filling or other forms of during the Neogene in two tectonically different anthropogenic stress such as pollution, eutrophica- phases. From Early to Middle Miocene (20 to 6 tion, introduction of exotic species, watershed million years ago), the Betic basin evolved together cultivation, road construction, mineral extraction, with the main movements of orogenic structuring of or ground-water pumping. the Cordillera, which were the collision between the The objective of this study was to characterize Alboran microplate, the so-called Internal Zones, ponds, pools, and playa-lakes in south-western see Figure 1B (F in legend), and the South-Iberian Spain, emphasizing their hydrological functioning Paleomargin (Sanz-de-Galdeano and Vera 1992). and conservation status. Finally, some basic guide- The deposits of the South-Iberian Paleomargin, of lines for small, shallow lake management and the Mesozoic age, where deformed, constituting the conservation are proposed, and focus on the unique so-called External Zones (Prebetic and Subbetic: see needs of each wetland category. Figure 1B in legend). During this synorogenic phase, a number of basins formed within the orogene as well as a foreland basin outside it, the METHODS proto-Guadalquivir Basin. The sediments filling them were deformed by the Betic orogeny. The Study Site second tectonic phase, in which the Neogene Andalusia contains an abundance of coastal and sedimentation occurred, took place during Late inland wetlands, including 17% of the total wetland Miocene to Quaternary. The main features of the area in Spain. To better guarantee the conservation orogeny were already determined and this was the and the sustainable use of these ecosystems, the context in which the Post-orogenic Basins formed, Environmental Council of Andalusia produced the many of them constituting closed depressions Andalusian Wetland Plan (Montes et al. 2004). This hosting small seas and vast wetlands. One of the document lists 129 small water bodies that are main characteristics of the Subbetic Unit of the Betic currently protected, and establishes a procedure to Cordillera is the presence of a great amount of clays, incorporate additional wetlands for protection. I marls, and evaporites of Triassic age and Keuper examined 33 of these wetlands located in the facies. Diapiric movements associated to the Triassic provinces of Malaga, Seville, and Cadiz (south-west evaporites also occur (Calaforra and Pulido-Bosch Spain) (Figure 1A). In Table 1, the characteristics of 1999), leading to the formation of gypsum karst the 33 wetlands are listed. features throughout the Subbetic that, in most cases Andalusia has a Mediterranean climate, although are also related to the existence and evolution of inter-annual variation in climatic condition can be many ponds, pools, and playa-lakes. In fact, the

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Table 1. Location of the wetlands studied. Typology: 1) Wetlands associated with permeable materials, 2) Wetlands associated with impermeable materials, and 3) Artificial wetlands AFS 5 average flooded area. UTM (Universal Transverse Mercator coordinate system) is related to 30 (longitude zone) and to S (latitude zone).

Code Name AFS(ha) UTMX UTMY Altitude Province Municipality Typology 1 Grande 8.3 384372 4107952 795 Malaga Archidona 1 2 Chica 7.9 383825 4106826 795 Malaga Archidona 1 3 Caja 9.7 369433 4098468 732 Malaga Antequera 1 4 Viso 6.9 369349 4097664 728 Malaga Antequera 1 5 Guadalhorce 67.0 370165 4059640 5 Malaga Ma´laga 3 6 Ratosa 23.0 349137 4118730 460 Malaga Alameda 2 7 FuentedePiedra 1271.6 343087 4108717 410 Malaga FuentedePiedra 1 8 Cerero 6.0 338777 4100959 480 Malaga Campillos 1 9 Camun˜as 2.7 339000 4100114 460 Malaga Campillos 2 10 Capacete 9.2 337585 4099141 460 Malaga Campillos 1 11 Marcela 6.1 336237 4098364 460 Malaga Campillos 1 12 Redonda 1.9 336145 4100030 460 Malaga Campillos 2 13 Salada 14.3 336126 4100707 460 Malaga Campillos 1 14 Dulce 57.4 336917 4102427 460 Malaga Campillos 2 15 Calderon 5.9 312190 4137412 160 Sevilla Osuna 1 16 Ballestera 25.4 307314 4138111 150 Sevilla Osuna 1 17 Zarracatin 62.5 250830 4102627 40 Sevilla Utrera 1 18 Alcaparrosa 6.0 249630 4104532 20 Sevilla Utrera 2 19 Arjona 9.3 248946 4103037 40 Sevilla Utrera 2 20 Hondilla 2.6 245061 4084676 100 Cadiz Espera 2 21 DulceZorrilla 6.3 244891 4083003 110 Cadiz Espera 2 22 SaladaZorrilla 12.0 244538 4084160 100 Cadiz Espera 2 23 Taraje 11.4 242813 4089905 130 Sevilla Cabezas 2 24 Charroao 4.9 241297 4092114 60 Sevilla Cabezas 2 25 Pilon 5.0 241783 4088275 80 Sevilla Lebrija 2 26 Galiana 1.7 240522 4087473 60 Sevilla Lebrija 2 27 Cigarrera 4.2 240041 4087287 70 Sevilla Lebrija 2 28 Vocesa 1.9 238316 4088596 70 Sevilla Lebrija 2 29 Pen˜a 5.7 240472 4088020 60 Sevilla Lebrija 2 30 Tollos 54.7 231031 4081984 54 Cadiz Jerez 1 31 Medina 120.1 227392 4056902 30 Cadiz Jerez 1 32 Paja 26.4 219620 4032342 50 Cadiz Chiclana 2 33 Tarelo 18.3 204051 4083261 3 Cadiz Sanlucar 3

majority of the wetlands studied are located near or 1000 ion chromatograph. Descriptions of land use, within the contact area of the detritic materials of impacts, and hydrological elements (drainages, the Guadalquivir basin and the impermeable evap- fences) were identified in the watersheds. History oritic materials of the Subbetic Unit of the Betic on the management and hydrological changes in the Cordillera (Rodrı´guez-Rodrı´guez et al. 2006). study wetlands was obtained by unstructured inter- views with local residents. The people interviewed had been or were still agricultural farmers with Field Surveys and Analytical Procedures a close association to the land containing the Hydrochemical and hydrogeological surveys were wetlands. Oral history is a recognized technique of carried out in the study sites from March 2004 to incorporating local environmental knowledge into November 2005. Simultaneously, plant surveys were ecosystem management (Robertson and McGee conducted and invertebrate samples were taken. 2003). Notes about the local geology and hydro- Wetlands were located using aerial photographs geology (1:5,000 scale) were compared with in- (1:20,000 scale) and topographical maps (1:10,000 formation from geological (1:50,000 scale) and scale). Temperature, conductivity, dissolved oxygen, hydrogeological (1:100,000 scale) maps. Information and pH were measured in situ, whereas major ions on a variety of previous studies on Andalusian where analyzed in the laboratory using a DIONEX- wetlands (Carrasco 1986, Linares 1990, Garcia-

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Jimenez 1991, Rosa 1992, Cruz-SanJuliań and this methodology, it is assumed that no regional Benavente 1996, Rendon 1996, Almećija 1997, ground-water flow (i.e., coming from outside the ITGE 1998, Linares and Rendoń 1999, CHG-IGME watershed) discharges into the wetlands and thus is 2001, Rodrı´guez-Rodrı´guez 2002, Carrasco et al. not considered in the water balance. If the evolution 2004, Garcıá 2004, Heredia et al. 2004, Montes et al. of the theoretical water level (V) obtained is similar 2004, Moreira and Montes 2005, Benavente et al. to the average hydroperiod observed in the wet- 2006a, b) or unpublished data from the Andalusian lands, then it is assumed that the water balance is Environmental Council was also consulted. correct. If regional ground-water discharge (water In order to determine ground-surface water inputs) or hydrological changes of the watersheds relationships, a simple water budget model on such as drainages (water outputs) occur, then the a monthly scale (Equation 1) was developed for hydroperiod would not adjust to the theoretical average climatic conditions in each of the systems water level obtained. studied. The water balance model methodology has been previously applied and validated in shallow lakes V ~ P E z S S z G G ð1Þ i 0 i 0 from western Andalusia (provinces of Seville and V is change in storage (i.e., water level if divided Cadiz). Detailed information about the methodolo- by average flooded surface, AFS). Under average gy can be found in two recently published technical conditions this component may not change although reports that are accessible online (www.chguadal- significant variations could be expected on a monthly quivir.es). To determine surface - ground water scale. P is rainfall onto the wetland (m) estimated relationships, permeability of the substratum was from nearby weather stations and multiplied by AFS chosen as the first environmental descriptor to 3 to obtain volume (m ); these data were available on establish a preliminary wetland classification for the website of the Spanish Ministry of Agriculture at western Andalusia. If the substratum was imperme- www.mapa.es/informes/siga (weather stations of able, run-off from the watersheds was expected to be Cadiz, Malaga, and Seville provinces). Evaporation relatively fresh and average salinity of the water from the flooded surface, E, was estimated from would be low. In addition, run-off erosion would ‘‘Class A’’ evaporation tank data obtained from the partially bury the salts dissolved from rock outcrops existing network of the Guadalquivir River Basin in the watersheds. If the substratum was permeable, Authority, also multiplied by AFS to obtain volume ground-water discharge into the wetlands could (m3). A soil water budget (Jensen et al. 1990) constitute a significant fraction of the water budget. considering a water holding capacity of 75 mm was In this situation, average water salinity could reach applied to each watershed to obtain Si + Gi. The soil higher values and the hydroperiod could also be water budget is a simple accounting method used to longer. Permeability of the substratum may be an estimate soil-water storage and water surplus by influencing factor on the water chemistry and, means of potential evapotranspiration (PET) calcu- consequently, on the composition of biological lated by the Thornthwaite method (Thornthwaite communities and human uses of wetlands. and Mather 1955) and precipitation. Surplus (Si + G ) is the fraction of the rainfall falling onto the i RESULTS watersheds that exceeds ET and soil retention and goes into the lakes both by surface and subsurface Wetlands from western Andalusia were grouped run-off. Considering that the wetlands are terminal, into three main categories (Figure 1): 1) wetlands S0 equals zero. G0 was not considered a priori in the related to permeable materials (playa lakes) with equation because the majority of the wetlands either the playa floor near the water table and thus studied were situated near the piezometric level or with a high average salt content in its waters over impermeable materials. Assuming negligible (discharge predominates), or the playa floor above regional ground-water recharge in this particular the water table and thus with a low average salt hydrogeological setting is in accordance with a num- content in its waters (recharge predominates); 2) ber of hydrogeological studies previously carried out wetlands associated with impervious materials in these wetlands and elsewhere (Linares 1990, Cruz- (ponds if permanent or pools if ephemeral); and 3) SanJuliań and Benavente 1996, Almećija 1997, Fan artificial wetlands, normally associated with aban- et al. 1997, ITGE 1998, Linares and Rendoń 1999, doned gravel and sand quarries and always perma- Rodrı´guez-Rodrı´guez 2002, Yechieli and Wood nent due to ground-water discharge. The main 2002, Carrasco et al. 2004, Heredia et al. 2004, features and mean values of some hydrological Moreira and Montes 2005, Rodrı´guez-Rodrı´guez et parameters of the three categories of wetlands are al. 2005, Benavente et al. 2006b). Therefore, using presented in Table 2 and Figure 2.

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Table 2. Main features and value ranges of some structural parameters of the three categories of wetlands from southern Spain. W/AFS: Watershed/Average Flooded Surface.

Wetland typology Dominant vegetation Human impacts Associated with permeable materials Basin area (ha) 103–104 Tamarix sp. Ground-water extraction W/AFS 4–11 Phragmites sp. Watershed cultivation Hydroperiod Seasonal Arthrocnemum sp. Road construction Salinity (mS/cm) 10–200 *discharge Salicornia sp. Drainages , 0.5 *recharge Associated with impermeable materials Basin area (ha) 10–103 Lentiscus sp. Watershed cultivation W/AFS 6–8 Phragmites sp. Road construction Hydroperiod Permanent–Ephemeral Typha sp. Drainages Salinity (mS/cm) 0.3–10 Juncus sp. Exotic species Artificial Basin area (ha) , 102 Tamarix sp. Arids or clay extraction W/AFS , 2 Phragmites sp. Ground-water extraction Hydroperiod Permanent Juncus sp. Road construction Salinity (mS/cm) 5–30 Arundo donax Exotic species

Wetlands Associated with Permeable Materials and intersects the surface in the lowest part of the closed depression. According to several authors For the occurrence and formation of playa lakes, (Duffy and Al-Hassan 1988, Fan et al. 1997), this several features have to occur simultaneously. The type of ecosystem can be labelled as a playa-lake. If most important one is the presence of a topograph- the lowest part of the depression is located in the ically closed depression of a considerable size (103 to center, an extensive playa-lake is formed (see 104 ha). In this depression, alluvial deposits may Figure 2A, left). Ground water from the watershed constitute an unconfined aquifer with significant flows towards the center of the basin that constitutes water resources. Normally, these depressions are the discharge zone of the unconfined aquifer under associated with tectonic extensional movements natural conditions. Salts and nutrients from upland (intra-mountainous basins), karstic dissolution of are deposited in the lake floor via both surface and evaporates, or both. The subsequent installation of ground water. This, together with the high evapo- a closed drainage network may form an endorheic ration rates, determines that playa-lakes draining basin. In this sense, Andalusia is a region in which sedimentary areas in southern Spain (with a pre- endorheism has been reported extensively (Dantin dominance of Triassic gypsum) typically exhibit 1940). Finally, the water table is normally shallow a high salt content in water. In playa-lakes where discharge processes predominate, the water salinity reached more than 200 mS/cm and hydrochemical composition was dominated by sodium and chloride (Figures 3 and 4B). Also, diffusive processes determine that ground water near the shore of the playa-lake may have a relatively high salt content and that a salt – freshwater interface forms near the shore as depicted in Figure 2A. Plant communities were determined by water salinity. Halophytes were common near the shore and in the outer parts reeds (Phragmites australis), together with bushes such as the salt cedar (Tamarix africana), were abundant. A summary of average water balance results and functional indicators that show whether there are different behaviors of the three typologies in terms Figure 2. Hydrogeological sketches indicating character- of the water balance can be seen in Appendix 1. In istics of three wetland typologie: A) Playa-lakes, B) Ponds the case of an extensive playa-lake, Fuente de Piedra and pools, and C) Artificial wetlands. (13 km2), permeable materials within the watershed

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Figure 5. Theoretical and observed water level development in Fuente de Piedra playa-lake (Malaga).

level evolution (from the water budget model) in this system, see Figure 5. Another type of playa-lakes existed when the extension of the unconfined aquifer (e.g., Lante- juela-Osuna ‘‘L.O.’’ aquifer, 350 km2) was greater than the extension of the watersheds of the playa- lakes (e.g., Calderon 0.06 km2 and Ballestera 0.25 km2). In this case, medium-sized playa-lakes with a high salt content also formed (see Figure 2A, right) and increases in ground-water salinity were conspicuous in the L.O. aquifer near the playa-lakes due to advective processes (see Figure 6). Finally, whenever the playa floor was above the piezometric level, recharge processes could also occur (see Figure 1A, left). This was the case in the Caja and Viso wetlands (#3and#4inTable1) Figure 3. Hydrochemical characteristics of water: A) classified as recharge playas (Carrasco et al. 2004). Piper diagram and B) Sho¨eller diagram. According to the results from the water budget model, an estimated average ground water recharge (150 km2) were abundant, and a salt-fresh water of 230 3 103 m3/year infiltrated to the underlying interface was formed near the shore (Rodrı´guez- carbonate aquifer. Rodrı´guez et al. 2006). As an example of measured water level evolution compared to calculated water Wetlands Associated with Impermeable Materials This type of wetland dominates the south of the Seville province and the northern part of the Cadiz province (Figures 1 and 2B). The dominant geology in the watersheds of these pools and ponds is the Triassic zone of the Subbetic Unit. Clays and clayey marls are profuse, constituting the most abundant lithologies. Typically, watersheds were small (10 to 103 ha, see Table 2), water salinity ranged from fresh to brackish (0.3 to 10 mS/cm), and the hydrochemical composition was mainly calcium and sulphate (see Figures 3 and 4C). The ratio between watershed area and average flooded surface (W/AFS) in these ponds and pools ranged from 6–8, depending on the annual difference between rainfall Figure 4. Frequency histograms of: A) Artificial wet- and actual evaporation (Figure 2B). Normally, lands), B) Playa-lakes, and C) Ponds and pools. surplus from the soil budget totals 125–200 mm

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or marls and clays of special interest are exploited. This was the case in Tollos playa-lake (Figure 6), where the hydrological regime had been altered due to the exploitation of attapulgite-rich clays. Three permanent artificial ponds were contributing to the salinization of the Lebrija aquifer associated with the Tollos playa-lake (see hydrogeological profile in Figure 6). At present time, the former playa-lake is dry all year and the salts deposited on the playa lake-floor have been lixiviated (Benavente et al. 2006a). In artificial wetlands, high evaporation rates contribute to fast salinization and also to changes in the hydrochemistry of ground water (see Figure 2C).

DISCUSSION Functions and Values of Wetlands of South-west Spain Some of the functions and values of wetlands from south-west Spain are listed in Table 3. Depending on the wetland typology and hydroperiod, functions and values differ. For example, in pools and playa-lakes, summer desiccation enhances mineralization of organic matter by creating aerobic conditions. Hence, temporary wetlands have a high potential to remove nitrogen from agricultural runoff (Brinson 1993, Brinson et al. 1995). Hydro- period, sediment properties, and high surface-to- Figure 6. Permeable and semi-permeable materials in volume ratios are all factors favoring nitrogen Lantejuela-Osuna and Lebrija aquifers. Electric conduc- removal. Fine sediments rich in organic matter tivity isolines (mS/cm) in ground water are represented favor denitrification and a high surface-to-volume near the playa-lakes studied. ratio favors rapid nitrogen uptake and processing. Ground-water discharge is a common feature of and evaporation from the flooded surface was near playa-lakes. As a consequence, even during droughts 1,000 mm/year. Consequently, watershed area de- the Fuente de Piedra, playa-lake maintains its water termines the equilibrium average flooded surface level without runoff because it received a net (AFS), assuming no regional ground-water input. ground-water discharge of 5.6 hm3 (Rodrı´guez- Equilibrium AFS can be thus estimated after the Rodrı´guez et al. 2006). Some values of the study calculation of the watershed area. Hydroperiod was wetlands vary depending on wetland typology, determined by the micro-topography (total depth) of mainly due to water chemistry. Saline wetlands are the wetland basin. used for salt production, while freshwater wetlands Vegetation growing on the watersheds was not are used in irrigation. Some values such as hunting very different from Mediterranean scrub communi- or research opportunities are common to all types ties (Lentiscus sp., Rosmarinus sp.). Shore vegetation (Table 3). was usually dominated by reeds and cattails. Finally, small water bodies in south-west Spain can be historically and culturally important resources that may not be sufficiently recognized. This Artificial Wetlands is another argument in favor of their conservation. Sand and gravel quarries are often abandoned, Salt extraction is a traditional activity carried out and become flooded within a few years due to since Roman times in playa-lakes of southern Spain. ground-water inputs from the unconfined aquifers Water harvesting and floodwater farming is another over which they are situated. Quarries are often traditional activity in wetlands of arid and semi-arid distributed along the coastal zone, where delta lands (Boers and Ben-Asher 1982). Hand-made alluvial materials are deposited. Continental sands walls have been built in many natural shallow water

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Table 3. Functions and values of wetlands from southern Spain.

Wetland typology Functions Values Services Associated with permeable Ground-water discharge/recharge Salt production Sediment retention materials Delay of surface water flows Tourism Flood prevention Production/recycling of organic matter Research Nutrient cycling Hunting Associated with impermeable Delay of surface water flows Livestock Sediment retention materials Production/recycling of organic matter Irrigation Flood prevention Drinking ponds Nutrient cycling Hunting Artificial Ground-water discharge Building materials - Industry - Drinking ponds - (if fresh) bodies to increase the hydroperiod of fresh water wetlands were cultivation and ground-water extrac- pools. Some of these structures or their remains can tion for irrigation. Cultivation can also occur in still be found in the wetlands of southern Spain. flooded wetlands themselves, leading to severe geomorphologic impacts and hydroperiod altera- tions (see Table 4). This situation normally occurred Human Impacts on Wetlands in the fresher wetlands, often associated with Despite the known ecological value of wetlands, impermeable materials (Dulce, Ratosa, Camun˜as, they are still exposed to a variety of impacts. As in or Alcaparrosa pools). many semiarid areas, water is in short supply in Human activities vary slightly, depending on the southern Spain and irrigation agriculture is exten- typology of the wetlands (Table 5). In general, sive. In playa-lakes, where ground-water inputs are grazing pressure was higher in wetlands associated important, aquifer overexploitation is an emerging with impermeable materials and fishing was com- threat. Table 4 relates human activities and impacts mon in artificial wetlands. Rubbish dumping and to resources in the wetlands studied. The most sand or gravel extraction occurred in a few heavily common human activities in the watersheds of those modified water bodies, such as Los Tollos playa-

Table 4. Human activities and impacts on wetland resources. Numbers in parentheses relate activities to impacts.

Resources Human activities Impacts Watershed 1 Cultivation Watershed geomorphology modifications (1, 2, 3, 4) 2 Sand and gravel extraction Elimination of watershed vegetation (1, 2, 3, 4, 6) 3 Rubbish dumping Alteration of hydrological processes (2, 4, 5, 6) 4 Use as Roads Elimination of natural plant communities (1, 2, 6) 5 Ground-water extraction Surface and ground-water pollution (1, 2, 3, 5) 6 Urbanization Landscape impact (1, 2, 3, 4, 6) Flooded surface 1 Water derivation for irrigation Wetland dessication (1) 2 Floodwater farming Alteration of hydroperiod (1, 2, 3) 3 Cultivation Geomorphological impacts (1, 2, 3, 5, 6) 4 Fishering Alteration of water salinity (1, 2, 5) 5 Salt extraction Alteration of aquatic communities (4, 5, 7) 6 Moto-cross and Quad vehicules 7 Introduction of exotic species Biological communities 1 Vegetation burning Extraction of endemic or rare species (2) 2 Plant collection Death of protected species (4) 3 Grazing Alteration of biological communities (1, 2, 3, 4) 4 Hunting Surface water eutrophication (3)

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Table 5. Dominant human uses in the three wetland typologies (%).

Typology Grazing Hunting Fishering Rubbish disposal Associated with permeable materials 42 100 20 26 Associated with impermeable materials 64 100 30 41 Artificial 0 100 100 0

lake. Rubbish disposal was also frequent in ponds ACKNOWLEDGMENTS and pools. Funding for this project was provided by the Guadalquivir River Basin Authority. Field assis- Management Recommendations tance was provided by F. Moral (University Pablo de Olavide) and J. Benavente (University of Hydrogeological characteristics of wetlands in Granada), whose knowledge in hydrogeology was western Andalusia strongly influence the physical, essential to this work. Assistance with GPS mapping chemical, and hydrological features of these water was provided by J.M. Bruque (University Pablo de bodies, and affect the kinds of human use and impact on these ecosystems. Thus, guidelines for Olavide) and with data management by V. Cifuentes conserving and restoring wetlands should take (Guadalquivir River Basin Authority). Suggestions a functional approach, with management plans by Dr. Harvey (USGS, Reston) and Dr. Batzer established at watershed scales. This approach has (University of Georgia) strengthened this paper. already achieved significant recovery of functions and values of other altered wetlands (Eckles et al. LITERATURE CITED 2002). In western Andalusia, water budgets for Almećija, C. 1997. Estudio hidrolo´gico de los enclaves lagunares ponds and pools are dominated by precipitation; del norte de la provincia de Ma´laga. Ph.D. Dissertation. whereas budgets for playa-lakes and many artificial University of Granada, Granada, Spain. wetlands are dominated by ground water. Natural Benavente, J., F. Moral, and M. Rodrı´guez-Rodrı´guez. 2006a. Definicioń del contexto hidrogeolo´gico de humedales anda- resource managers wonder how much water can be luces. Lagunas de Ca´diz. Guadalquivir River Basin Authority, extracted from aquifers without harming protected Seville, Spain. wetlands. The answer requires information that can Benavente, J., F. Moral, and M. Rodrı´guez-Rodrı´guez. 2006b. only be available by detailed hydrogeological study. Definicioń del contexto hidrogeolo´gico de humedales andaluces. Lagunas de Sevilla Guadalquivir River Basin Authority, The watershed of each pond, pool, or playa-lake Seville, Spain. constitutes a pathway for inputs of particulate Biggs, J., P. Williams, M. Whitfield, P. Nicolet, and A. organic matter and nutrients to the wetland. Weatherby. 2005. 15 years of pond assessment in Britain: results and lessons learned from the work of Pond Conserva- Seasonal rainfall, typical of Mediterranean climates, tion. Aquatic Conservation: Marine and Freshwater Ecosys- produce pulsed inputs of matter that determines tems 15:693–714. wetland structure and ecosystem function. Conse- Boers, T. M. and J. Ben-Asher. 1982. A review of rainwater harvesting. Agricultural Water Management 5:145–58. quently, processes at the watershed scale such as loss Boix, D., S. Gasco, J. Sala, M. Martino, J. Gifre, and X. of natural vegetation, increased cultivation, or Quintana. 2005. A new index of water quality assessment in intensive ground-water extraction can have sub- Mediterranean wetlands based on crustacean and insect stantial effects on the physical and biological assemblages: the case of Catalunya (NE Iberian Peninsula). Aquatic Conservation: Marine and Freshwater Ecosystems structure of wetlands. 15:635–51. Conservation needs are different for every wet- Brinson, M. M. 1993. A hydrogeomorphic classification for land typology, so the potential management solu- wetlands. US Army Corps of Engineer Waterways Experiment Station, Vicksburg, MS, USA. Tech. Rep. WRP-DE-4. tions must also be type-specific. Designating pro- Brinson, M. M., F. R. Hauer, L. C. Lee, W. L. Nutter, R. D. tected areas is not always enough to deal with the Rheinhardt, R. D. Smith, and D. Whigham. 1995. A guidebook range of pressures on wetlands. For example, playa- for application of hydrogeomorphic assessments to riverine wetlands. US Army Engineer Waterways Experiment Station, lake typologies are hydrologically connected to Vicksburg, MS, USA. unconfined aquifers and aquifer overexploitation Calaforra, J. M. and A. Pulido-Bosch. 1999. Gypsum karst that extends far beyond the playa-lake watershed features as evidence of diapiric processes in the Betic Cordillera, can still desiccate the wetland. For ponds and pools Southern Spain. Geomorphology 29:251–64. Carrasco, F. 1986. Contribucioń al conocimiento de la cuenca the risks from drainage activities, eutrophication, alta del rıó Guadalhorce el medio fı´sco; hidrogeoquı´mica. and cultivation must be managed at watershed Ph.D. Dissertation. University of Granada, Granada, Spain. scales. Both examples indicate the need for imple- Carrasco, F., B. Andreo, I. Vadillo, D. Sańchez, I. Pe´rez, J. Vıás, and A. Cobos. 2004. Definicioń del contexto hidrogeolo´gicode mentation of properly researched management humedales andaluces. Lagunas de Ma´laga. Andalusian Minis- strategies for hydrological systems as a whole. try of Environment, Seville, Spain.

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Wetlands wetl-27-04-05.3d 28/9/07 16:40:21 828 Rodrı´guez-Rodrı´guez, HYDROGEOLOGY OF SMALL SPANISH WETLANDS 829 100. A 3 an altered alteration Degree of Outputs) + indicates alteration of the % 5 . 0 indicates ground-water recharge). Salinity . (Inputs - Outputs/Inputs 5 Hypogenic Closed Permanent Low Hypogenic ClosedEpigenic MixedEpigenic Seasonal Mixed Semipermanent Seasonal Low Low Mixed Closed Seasonal Low setting Inputs Outputs Hydroperiod Hydrogeological karstification) karstification) karstification) karstification) hydrogeological basin Dolines (gypsum Dolines (gypsum Clays and marls - alluvial Epigenic Mixed? Seasonal Low 0 indicates ground-water discharge; , imbalance Main cause of discharge discharge recharge ? ) 4 - Clays and marls Epigenic Mixed* Seasonal Low 5 - Clays and marls Epigenic Closed Semipermanent 2 - Clays and marls Epigenic Closed Seasonal Low 6 - Clays and marls Epigenic Closed Seasonal Low 6 - Clays and marls Epigenic Closed Seasonal Low 49 Regional ground-water 47 Regional ground-water 38 Ground-water discharge Alluvial (quarries) Hypogenic Closed Permanent - 2 2 2 2 2 % ( 2 2 2 Imbalance indicates water input from the surface watershed and output from evaporation. An imbalance of 3 0 - Endorheic % 5 , ˜as 2 19 Drainage Clays and marls Epigenic Mixed* Ephemeral High 1 mS/cm; 2) 1–10 mS/cm; and 3) 10–200 mS/cm. Epigenic: dominated by surface water inputs from the watershed; Hypogenic: dominated by ground , Piedra Code Name Salinity Appendix I. Summary of the water balance results for 33 wetlands in terms of the water budget imbalance water imbalance of watershed (drainage, overflow) or a relationship with permeable materials ( regimes. For more detailed information of wetland water balances go to: www.chguadalquivir.es (technical reports). ranges: 1) water flows. Closed drainage: outputs from evaporation; Open drainage: outputs from surface run-off or infiltration. An asterisk (*) indicates hum 1 Grande 2 2 Chica 2 Low 3 Caja4 Viso5 Guadalhorce 1 3 1 26 Ground-water 48 recharge Ground-water recharge Dolines (gyp-carb Dolines (gyp-carb 67Fuentede Ratosa 2–3 2 - Clays and marls Epigenic Closed Seasonal Low 23Low Taraje2425 Charroao Pilon 1–2 1 1–2 20 Overflow 1 17 GroundwaterGround-water - Clays and marls Epigenic Clays and marls Closed Epigenic Open* Ephemeral Semipermanent High Low 22 Salada Zorrilla 2 1516 Calderon17 Ballestera18 Zarracatin19 AlcaparrosaLow 3 Arjona20 3 321 2 Hondilla Dulce Zorrilla 0 2 0 2 28 0 2 Drainage 17 6 Basin degradation - Overflow - - Clays Clays and and marls marls Alluvial Alluvial Clays and marls Epigenic Epigenic Clays and marls Closed Mixed* Seasonal Mixed Epigenic* High Epigenic Epigenic* Mixed* Closed Seasonal Mixed* Mixed* Seasonal Seasonal Seasonal Semipermanent Medium Low Medium Low 14 Dulce 2 1213 Redonda Salada 2–3 3 11 Basin degradation Clays and marls Epigenic Closed Ephemeral High 89Camun Cerero1011 Capacete Marcela 2 2 2–3 5 29 Drainage - Clays and marls Clays and marls Epigenic Mixed* Seasonal Epigenic Medium Closed Seasonal Low 26 Galiana 2 22 Drainage - Overflow Clays and marls Epigenic Mixed* Seasonal Medium

Wetlands wetl-27-04-05.3d 28/9/07 16:40:21 829 830 WETLANDS, Volume 27, No. 4, 2007 alteration Degree of Epigenic Mixed Semipermanent setting Inputs Outputs Hydroperiod Hydrogeological karstification) imbalance Main cause of ) 43 Ground-water discharge Alluvial (quarries) Hypogenic Closed Permanent - % ( 2 Imbalance ˜a 2 4 - Clays and marls Epigenic Closed Seasonal Low Code Name Salinity Low 3233 Paja Tarelo 1–2 2 6 Overflow Clays and marls Epigenic Closed Seasonal Medium 2728 Cigarrera29 Vocesa30 Pen 31 Tollos 2 Medina 1–2 31 1 2 40 Drainage Drainaje 11 30 Mining Ground-water recharge Dolines (gypsum Clays and marls Clays and marls Epigenic Special clays Epigenic Mixed* Seasonal Open* Ephemeral Medium High Epigenic* Mixed* Ephemeral High Appendix I. Continued.

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