1020 © 2019 The Authors Hydrology Research | 50.4 | 2019 Contribution of decision support systems to water management improvement in basins with high evaporation in Mediterranean climates Verónica Ruiz-Ortiz, Santiago García-López, Abel Solera and Javier Paredes ABSTRACT The entry into force of Directive 2000/60/EC of the European Parliament and the Council of 23 Verónica Ruiz-Ortiz (corresponding author) Department of Industrial Engineering and Civil October 2000 established a new model for the management and protection of surface water and Engineering, University of Cadiz, groundwater in Europe. In this sense, a thorough knowledge of the basins is an essential step in Campus Bay of Algeciras, Avda. Ramón Puyol s/n achieving this European objective. The utility of integrative decision support systems (DSS) for 11202 Algeciras, Cádiz, Spain decision-making in complex systems and multiple objectives allows decision-makers to identify E-mail: [email protected] characteristics and improve water management in a basin. In this research, hydrological and water Santiago García-López Department of Earth Sciences, management resource models have been combined, with the assistance of the DSS AQUATOOL, with University of Cadiz, the aim of deepening the consideration of losses by evaporation of reservoirs for a better design of Campus Río San Pedro s/n 11510 Puerto Real, Cádiz, the basin management rules. The case study treated is an Andalusian basin of the Atlantic zone Spain (Spain). At the same time, different management strategies are analysed based on the optimization Abel Solera Javier Paredes of the available resources by means of the conjunctive use of surface water and groundwater. Research Institute of Water and Environmental Engineering, Key words | conjunctive use, decision support systems (DSS), evaporation, reservoir, water (IIAMA), Universitat Politècnica de València, resources systems Camino de Vera s/n 46022, Valencia, Spain INTRODUCTION Water resources are under increasing pressure associated consumption of more than 70% of the total freshwater of with population growth, the development of economic the world. In fact, in some basins, water management is activities and the potential scenarios of climate change focused almost exclusively on supplying agricultural demands, that predict a significant decrease in precipitation and as is the case of this study on the Barbate River basin (Cádiz, streamflows (Alcamo et al. ; González-Zeas ). Spain). Measures aimed at more efficient use of water in Water resource management includes two basic com- agriculture have been developed in recent times. Strosser ponents and their relationships. On the one hand, the et al.() proposes implementation of a system based on sources of the resource must be managed; on the other the recovery of the cost of water from the payment of the hand, water demand must be met. In relation to the latter, users. Other measures are aimed at increasing the efficiency irrigated agriculture is the main demand for water, with of irrigation systems (Singh a), to alleviating the effects of droughts on agriculture (Ghabaei Sough et al. )or This is an Open Access article distributed under the terms of the Creative reducing the soil salinization in arid areas (Li et al. ). Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited However, the optimization of water can also be (http://creativecommons.org/licenses/by/4.0/). analysed from the point of view of the availability. For doi: 10.2166/nh.2019.014 Downloaded from https://iwaponline.com/hr/article-pdf/50/4/1020/584650/nh0501020.pdf by guest on 13 September 2019 1021 V. Ruiz-Ortiz et al. | DSS to water management improvement, basins with high evaporation Hydrology Research | 50.4 | 2019 this, the use of hydrological models, of decision support of surface water and groundwater, helping managers to systems (DSS) or a combination of both (Pedro-Monzonís decide which management is the most suitable. For this et al. ) are very useful. Singh (b) performed an aim, the decision support system AQUATOOL and its exhaustive compilation of the different studies carried out SIMGES module have been used. As a characteristic on computational models for the conjunctive use of water; element of this basin, the only surface reservoir with multi- these extend from the first models (Tyagi & Narayana annual regulation capacity has a significant loss due to ), whose objectives were to define the amount of surface direct evaporation. Therefore, the contribution of the DSS water and groundwater needed for irrigation, to the most to the quantification of this output of the balance has been recent (Rezapour Tabari & Soltani ; Singh c), in analysed, and management alternatives aimed at mitigating which a very high number of sources and demands are simu- this water problem have been proposed. lated to optimize the resource by means of programming techniques in constant evolution (Condon & Maxwell ). Therefore, currently, the DSS are supported by easy- STUDY AREA to-use computer software such as AQUATOOL (Andreu et al. ), WARGI (water resources system optimization General characteristics of the Barbate River basin aided by graphical interface) (Sechi & Zuddas ) and AQUATOR dveloped by Oxford Scientific Software in 2001. The study area is located on the Atlantic coast of Andalusia Surface water and groundwater are two components (SW Spain). Specifically, it is in the province of Cadiz that interact according to climatic, terrain relief, geological (Figure 1). The basin of the Barbate River, with a surface and biotic factors (Sophocleous ). Therefore, an of approximately 1,330 km2, has a smooth orography for impact on one of them will inevitably affect the quantity most of its area, mainly with elevations not exceeding and quality of the other (Tanvir Hassan ). However, 200 m above sea level (a.s.l.), with slopes of less than 3% surface water and groundwater have traditionally been on average in the lower basin. Nevertheless, in the upper considered as two distinct and independent components of basin, elevations reach 1,095 m a.s.l., and the slopes are the hydrological cycle. In the 1970s, the concept of ‘hydro- quite pronounced. schizophrenia’ appeared, a term proposed to designate the The climate context is Mediterranean with Atlantic mental separation that people make between the superficial influence. The average annual precipitation is close to waters (that they see) from the subterranean (that they do 800 mm/year, the average annual temperature is approxi- not see). Since then, consciousness has developed about mately 18 C, the potential and real evapotranspiration is the importance of the interactions of these two components about 1,110 and 585 mm/year, respectively. On the other of the hydrological cycle to meet human needs, as well as hand, the wind is a very characteristic feature of the studied ecological functions in riparian zones and other dependent area. The most frequent are the West (Poniente) winds and ecosystems. In addition, current legal regulations such East (Levante) winds. Poniente winds are moist, fresh and as the Water Framework Directive (EP ) have led to a major research activity on issues related to joint management. This research is part of a project that has the support of the Ecological Transition Ministry (Government of Spain), through the Biodiversity Foundation, in the matter of climate change. Its main objective is to deepen the knowl- edge of the management of an Andalusian hydrographic basin in the Atlantic zone (Spain) and to analyse the possible management strategies based on the optimization of the available resources by means of the conjunctive use Figure 1 | Location of the studied area. Downloaded from https://iwaponline.com/hr/article-pdf/50/4/1020/584650/nh0501020.pdf by guest on 13 September 2019 1022 V. Ruiz-Ortiz et al. | DSS to water management improvement, basins with high evaporation Hydrology Research | 50.4 | 2019 Figure 2 | Left: hydrological elements: hydrographic network, reservoirs and groundwater bodies. Right: location of irrigated farmland and natural parks. cause precipitation to ascend towards the interior, with the In terms of geological characteristics, the Barbate humidity brought from the sea being condensed. However, River basin belongs to Gibraltar’s flysch unit. At least the Levante winds are warm and dry and can reach two independent operating aquifer systems are recog- speeds of more than 100 km/h. nized. The first, identified in the Hydrological Plan The main river of the basin is the Barbate River, which (Junta de Andalucía ) as a groundwater body originates in the Aljibe Sierra and opens into the Atlantic (GWB), Benalup (062.014), integrates a single outcrop Ocean. Along its left margins, it receives the Celemín and (33 km2 of area) of sand and carbonated calcarenites. Almodóvar Rivers. The three rivers are regulated by their This aquifer is in a topographical position several tens of homonymous reservoirs: Barbate (228 hm3 capacity), Cele- metres elevated over the hydrographic network. The mín (45 hm3) and Almodóvar (5.7 hm3). From its right second, with approximately 93 km2 of surface, identified margin, the Barbate River receives the contributions of the as GWB Barbate (062.013), presents several outcrops River Álamo, without regulation (Figure 2, left). The man- of permeable rocks (calcarenites, Pliocene sands and Qua- agement of the Barbate and Celemín reservoirs is carried ternary and alluvial deposits) disconnected at the surface, out jointly for the irrigation of 12,230 ha. Almodovar reser- but they predictably have connection in the subsoil. In the voir is multipurpose: water supply (18,000 inhabitants) and study basin, in addition to the surface infrastructures, irrigation (362.6 ha) (Figure 2, right). Downstream from many (>200) groundwater catchment wells are present, the reservoirs, the rivers are used as distribution channels and these provide water to supply the approximately to the consuming areas, for which a series of floodgates 9,000 inhabitants and irrigation for approximately and pumps have been built to allow water diversion.