Abel Solera

A decision support system for water quality issues in the Manzanares River (Madrid, Spain).

The Manzanares River, located in Madrid (Spain), is the main water supplier of a highly populated region, and it also receives wastewater from the same area. The effluents of eight Waste Water Treatment Plants (WWTPs) downstream of the river, which represent 90% of the flow in the middle and lower parts of the river, are the primary sources of water pollution. Although the situation has improved slightly in the last two years, the water in the river is highly polluted, making it uninhabitable for aquatic life. Water quality modelling is typically used to assess the effect of treatment improvements in water bodies. In this work, the GESCAL module of the Aquatool Decision Support System Shell was used to simulate water quality in the Manzanares River. GESCAL is appropriate for modelling in an integrated way water quality for whole water resources systems, including reservoirs and rivers. A model was built that simulates conductivity, phosphorous, carbonaceous organic matter, dissolved oxygen, organic nitrogen, ammonia, and nitrates. The period from October 2006 to September 2008 was selected for calibration due to the many treatment modifications that occurred during this time. An earlier and longer period, from October 2000 to September 2006, was used for validation. In addition, a daily model was used to analyse the robustness of the GESCAL model. Once the GESCAL model was validated, different scenarios were considered and simulated. First, different combinations of nutrient elimination among the different WWTPs were simulated, leading to the conclusion that investments have to focus on three of the proposed WWTPs. Moreover, these treatments will not be sufficient to maintain fish habitat conditions at all times. Additional measures, such as the increment of the flow in the river or oxygen injection, were simulated. Incrementing the flow of the Manzanares River has been shown to be an efficient means of increasing water quality, but this implies an increment in the risk of water scarcity situations in the Madrid water supply system.

A Model for Solving the Optimal Water Allocation Problem in River Basins with Network Flow Programming When Introducing Non-Linearities

The allocation of water resources between different users is a traditional problem in many river basins. The objective is to obtain the optimal resource distribution and the associated circulating flows through the system. Network flow programming is a common technique for solving this problem. This optimisation procedure has been used many times for developing applications for concrete water systems, as well as for developing complete decision support systems. As long as many aspects of a river basin are not purely linear, the study of non-linearities will also be of great importance in water resources systems optimisation. This paper presents a generalised model for solving the optimal allocation of water resources in schemes where the objectives are minimising the demand deficits, complying with the required flows in the river and storing water in reservoirs. Evaporation from reservoirs and returns from demands are considered, and an iterative methodology is followed to solve these two non-network constraints. The model was applied to the Duero River basin (Spain). Three different network flow algorithms (Out-of-Kilter, RELAX-IV and NETFLO) were used to solve the allocation problem. Certain convergence issues were detected during the iterative process. There is a need to relate the data from the studied systems with the convergence criterion to be able to find the convergence criterion which yields the best results possible without requiring a long calculation time.

Integrating ecosystem services in river basin management plans

Summary According to the European Union Water Framework Directive, river basin management plans must include a programme of measures, with a series of management actions aiming to achieve good ecosystem status of all water bodies within the basin. The design and later prioritization of these management actions is, in theory, done through cost-effectiveness analysis (CEA), which compares management action costs with expected improvements in ecosystem status. However, such an approach does not consider the effects of management actions on human well-being resulting from changes in the provision of ecosystem services. We propose to complement the current CEA approach with a cost–benefit analysis (CBA) integrating the effects of management actions on the provision of ecosystem services, therefore moving from a single-objective to a multiobjective approach. We propose a flexible methodological framework based on a combination of CEA and CBA that can be easily adapted to different case studies. To test the applicability of our approach, we applied it to an impaired basin, the Llobregat River basin (north-eastern Iberian Peninsula). The analysis considers management actions selected from the programme of measures under implementation: establishment of environmental river flows, improvement of river connectivity, treatment of urban wastewater and reduction in saline pollution; and the effects on a series of ecosystem services: water provisioning, waste treatment and habitat for species. Results revealed that management actions designed to improve ecosystem status do not necessarily improve human well-being through changes in the provision of ecosystem services. The implementation of the CEA and CBA allowed the identification of management actions providing the best trade-offs between improvements of ecosystem status and human well-being. For example, the establishment of environmental river flows in the upper Llobregat River was the management action that maximized the balance between gains in ecosystem status and human well-being. Synthesis and applications. Overall, the combination of cost-effectiveness analysis and cost–benefit analysis supports a more informed and transparent decision-making in the implementation of river basin management plans, better assisting stakeholders to prioritize those management actions providing the optimal win–win results.

Integrating water management, habitat modelling and water quality at the basin scale and environmental flow assessment: case study of the Tormes River, Spain

Abstract Multidisciplinary models are useful for integrating different disciplines when addressing water planning and management problems. We combine water resources management, water quality and habitat analysis tools that were developed with the decision support system AQUATOOL at the basin scale. The water management model solves the allocation problem through network flow optimization and considers the environmental flows in some river stretches. Once volumes and flows are estimated, the water quality model is applied. Furthermore, the flows are evaluated from an ecological perspective using time series of aquatic species habitat indicators. This approach was applied in the Tormes River Water System, where agricultural demands jeopardize the environmental needs of the river ecosystem. Additionally, water quality problems in the lower part of the river result from wastewater loading and agricultural pollution. Our methodological framework can be used to define water management rules that maintain water supply, aquatic ecosystem and legal standards of water quality. The integration of ecological and water management criteria in a software platform with objective criteria and heuristic optimization procedures allows realistic assessment and application of environmental flows to be made. Here, we improve the general methodological framework by assessing the hydrological alteration of selected environmental flow regime scenarios. Editor D. Koutsoyiannis; Guest editor M. Acreman Citation Paredes-Arquiola, J., Solera, A., Martinez-Capel, F., Momblanch, A., and Andreu, J., 2014. Integrating water management, habitat modelling and water quality at the basin scale and environmental flow assessment: case study of the Tormes River, Spain. Hydrological Sciences Journal, 59 (3–4), 878–889.

Methodology for Drought Risk Assessment in Within-year Regulated Reservoir Systems. Application to the Orbigo River System (Spain)

Drought occurrence and its related impacts are a major concern in many river basins throughout the world. In the last years, drought management procedures have moved from a crisis approach towards a more sensitive preparedness approach. Drought plans development has arisen as an effective way of providing measures and actions to manage drought situations. However, due to each river basin has different operation characteristics, drought management requires a different approach in order to be efficient. Decision support tools are a great ally of water managers, especially in situations of high water stress and hydrologic uncertainty, allowing them to in-deep analyze the system and finding the best measures to minimize the risk of a system failure. This paper studies the difficulties of only using an indicator system based in current and past data to assess the drought risk in within-year regulated reservoir systems. It proposes the complementary use of a general risk assessment methodology to anticipate the future probable status of the system and defining the current drought scenario. It shows how the complementary use of a monitoring system and a risk assessment decision support system may improve the drought detection process allowing water managers optimizing the selection of mitigation measures and minimizing the probability of overreaction during a drought situation.

Drought Planning and Management in the Júcar River Basin, Spain

In the Jucar River Basin, water scarcity and hydrological variability produce frequent and long hydrological droughts. Preparation for droughts is achieved through (a) integrated river basin planning, including proactive measures that minimize the risk of operative droughts (i.e., failure of the system to provide water services); (b) special drought plans, including continuous monitoring of drought indexes in order to detect the risk in medium- to short-term management, and sets of proactive and reactive measures for different scenarios (i.e., normal, pre-alert, alert, and emergency); and (c) participatory drought management by means of a special drought committee, to mitigate the impact of droughts and find suitable compromise solutions to provide an equilibrium between economic sectors needs and environmental protection. We will illustrate how these three processes were applied in the recent 2005/2008 drought, and highlight the importance of up-to-date integrative decision support systems in enhancing and facilitating our ability to address drought.

Development of operating rules for a complex multi-reservoir system by coupling genetic algorithms and network optimization

Abstract An alternative procedure for assessment of reservoir Operation Rules (ORs) under drought situations is proposed. The definition of ORs for multi-reservoir water resources systems (WRSs) is a topic that has been widely studied by means of optimization and simulation techniques. A traditional approach is to link optimization methods with simulation models. Thus the objective here is to obtain drought ORs for a real and complex WRS: the Júcar River basin in Spain, in which one of the main issues is the resource allocation among agricultural demands in periods of drought. To deal with this problem, a method based on the combined use of genetic algorithms (GA) and network flow optimization (NFO) is presented. The GA used was PIKAIA, which has previously been used in other water resources related fields. This algorithm was linked to the SIMGES simulation model, a part of the AQUATOOL decision support system (DSS). Several tests were developed for defining the parameters of the GA. The optimization of various ORs was analysed with the objective of minimizing short-term and long-term water deficits. The results show that simple ORs produce similar results to more sophisticated ones. The usefulness of this approach in the assessment of ORs for complex multi-reservoir systems is demonstrated. Citation Lerma, N., Paredes-Arquiola, J., Andreu, J., and Solera, A., 2013. Development of operating rules for a complex multi-reservoir system by coupling genetic algorithms and network optimization. Hydrological Sciences Journal, 58 (4), 797–812.

Key issues for determining the exploitable water resources in a Mediterranean river basin.

One of the major difficulties in water planning is to determine the water availability in a water resource system in order to distribute water sustainably. In this paper, we analyze the key issues for determining the exploitable water resources as an indicator of water availability in a Mediterranean river basin. Historically, these territories are characterized by heavily regulated water resources and the extensive use of unconventional resources (desalination and wastewater reuse); hence, emulating the hydrological cycle is not enough. This analysis considers the Jucar River Basin as a case study. We have analyzed the different possible combinations between the streamflow time series, the length of the simulation period and the reliability criteria. As expected, the results show a wide dispersion, proving the great influence of the reliability criteria used for the quantification and localization of the exploitable water resources in the system. Therefore, it is considered risky to provide a single value to represent the water availability in the Jucar water resource system. In this sense, it is necessary that policymakers and stakeholders make a decision about the methodology used to determine the exploitable water resources in a river basin.

Water accounting for stressed river basins based on water resources management models

Water planning and the Integrated Water Resources Management (IWRM) represent the best way to help decision makers to identify and choose the most adequate alternatives among other possible ones. The System of Environmental-Economic Accounting for Water (SEEA-W) is displayed as a tool for the building of water balances in a river basin, providing a standard approach to achieve comparability of the results between different territories. The target of this paper is to present the building up of a tool that enables the combined use of hydrological models and water resources models to fill in the SEEA-W tables. At every step of the modelling chain, we are capable to build the asset accounts and the physical water supply and use tables according to SEEA-W approach along with an estimation of the water services costs. The case study is the Jucar River Basin District (RBD), located in the eastern part of the Iberian Peninsula in Spain which as in other many Mediterranean basins is currently water-stressed. To guide this work we have used PATRICAL model in combination with AQUATOOL Decision Support System (DSS). The results indicate that for the average year the total use of water in the district amounts to 15,143hm(3)/year, being the Total Water Renewable Water Resources 3909hm(3)/year. On the other hand, the water service costs in Jucar RBD amounts to 1634 million € per year at constant 2012 prices. It is noteworthy that 9% of these costs correspond to non-conventional resources, such as desalinated water, reused water and water transferred from other regions.

Assessment of evolutionary algorithms for optimal operating rules design in real Water Resource Systems

Two evolutionary algorithms (EAs) are assessed in this paper to design optimal operating rules (ORs) for Water Resource Systems (WRS). The assessment is established through a parameter analysis of both algorithms in a theoretical case, and the methodology described in this paper is applied to a complex, real case. These two applications allow us to analyse an algorithms properties and performance by defining ORs, how an algorithms termination/convergence criteria affect the results and the importance of decision-makers participating in the optimisation process. The former analysis reflects the need for correctly defining the important algorithm parameters to ensure an optimal result and how the greater number of termination conditions makes the algorithm an efficient tool for obtaining optimal ORs in less time. Finally, in the complex real case application, we discuss the participation value of decision-makers toward correctly defining the objectives and making decisions in the post-process. SCE-UA and Scatter Search are assessed in order to design optimal operating rules.An analysis of the parameters is carried out to determinate the best stop criteria.The analysis carried out shows the most influential parameters.SCE-UA algorithm, applied in real cases, seems to be the most efficient algorithm.A way to transmit results is presented in order to make the decision-making easier.