Search

Studying the complex adaptability of regional water resources systems (WRS) plays an important role in promoting the sustainable utilization of water resources and improving the adaptation of WRS to environmental change. This study proposed a comprehensive co-evolution model, based on the conditions of the elements and on the mechanism of their interaction, to study the adaptive development of WRS. Using the model, the survival fitness of each subsystem, the coordination degree between each subsystem, and the survival fitness of the WRS were obtained, and the main factors that affect the adaptation of the WRS were analyzed. Shandong Province in China was used as an example. The results showed that during 2006-2015, the average annual survival fitness of the resource, social, economic, and ecological subsystems was 0.257, 0.282, 0.257, and 0.251, respectively, which indicated a low adaptability for each subsystem. The coordination degree between each subsystem (resource-society, resource-economy, resource-ecology, social-economic, social-ecological, and economic-ecological) was 0.319, 0.355, 0.334, 0.364, 0.333, and 0.351, respectively, which indicated minimal coordination between each subsystem. The average annual survival fitness of the WRS was 0.551, and the adaptability of the WRS was classified as basic. Further analysis revealed that the coordination problem caused by the interaction of the elements in each subsystem was responsible for the low adaptability. The coordination problem, therefore, places severe constraints on the adaptive development of WRS. Therefore, solving the problem of coordination between elements is fundamental to improving the adaptability of WRS and promoting its sustainable development. [ABSTRACT FROM AUTHOR]

The paper presents a set of experiments on the Rolling Horizon Technique (RHT), applied to the management of a multi-reservoir, multipurpose water resources system with over-year behaviour. In the RHT, decisions on releases from reservoirs are taken for a number of time steps ahead (the Forecasting Horizon - FH) through an optimization model, based on the present water availability in reservoirs and on some forecasts of future inflows over the FH. Only the decision concerning the first time step (the current month) is then implemented, as new information on reservoir levels and forecasts becomes available so that the process can start again with updated information. The paper investigates how the quality of forecasts and the length of the FH impact on the effectiveness of the decisions taken. The evaluation exercise is carried out in two different demand scenarios considering some deficit-related indices, such as TSSD, the Sum of Squared Standardized Deficits, over an Operation Horizon (OH) of forty years. The scenarios are designed to evaluate the role of different demand levels (corresponding to higher/lower stress) on system's behaviour. Results show that in systems with over-year behaviour, effective forecasts (here simulated through the best possible: actually occurred inflows from the current month up to the end of water year) seem to add little value to system's operation compared to the most naive forecast (average monthly values), especially in contexts characterized by high pressure on resources. Where there is less pressure on resources, good-quality forecasts are more effective to improve operation. A FH of 24 months seems to enhance significantly system's performances compared to a FH of 12 months, while FHs longer than two years produce no improvements in system's performances. The paper also tries to define the limits of a finite-horizon operation technique such as the RHT by benchmarking it with an idealistic release schedule obtained by a model that performs allocation with Perfect Foresight over the whole Operation Horizon. [ABSTRACT FROM AUTHOR]

The paper introduces and applies a methodology to screen investments aimed at reducing water supply risks due to hydrologic failures in headwork systems for municipal use, based on the principles of cost-benefit analysis. As risk includes both the probability of a failure and its effect, the methodology combines a simulation module of the system, fed by a stochastic hydrologic input to reproduce the probability distribution of the failures, with a metric for supply failure damage provided by the price - demand relationship for municipal water. Benefits are assessed as the averted damage compared to a base case without investments. This approach is then combined with the classic discounted cashflow approach of cost - benefit analysis to allow for the dynamics of both water supply and demand due to trends in population growth, individual consumption and, above all, planned reduction of losses in water distribution networks. The methodology is applied to screen a number of different supply-side projects for the headwork system supplying Apulia, in southern Italy featuring both regulated surface and groundwater resources and providing drinking water to over 4,000,000 persons. The procedure allows both ranking of single projects by their economical performances and the economic evaluation of combinations of different projects. The study also aims to assess the impact of the selected time scale, of cross-correlation among production sites, and of the specification of the demand function on projects' economic indicators. Results show that each modelling assumption has a considerable impact on the value of the economic indicators in absolute terms, but ranking of the different projects seems to be less sensitive to such modelling aspects. [ABSTRACT FROM AUTHOR]

This paper offers a methodology that enables characterisation of the behaviour of water resources systems under the impact of climate change through assessment of sensitivity patterns in a wide range of hydrologic variations produced by such change. Analysis is based on the application of two indicators that, in turn, draw on the results of a system optimisation model. Under this methodology the potential sensitivity of water resources systems in the cases of different climate projections are visualised, allowing those systems that require special attention in their adaptation to climate change to be identified. The methodology is applied to three basins located in Spain: Guadalquivir, Ebro and the Spanish part of the international basin Duero. [ABSTRACT FROM AUTHOR]

One crucial aspect of drought management plans is to establish a link between basin drought state and management actions. Basin state is described by a drought indicator system that includes variables like precipitation, streamflow, reservoir inflow, reservoir storage and groundwater piezometric levels. Basin policy consists on a catalogue of management actions, ranging from enforcing demand reduction strategies to establishing priority of users to allocate scarce water or approving emergency works. In this paper, the methodology applied in the Tagus Basin Drought Management Plan to link operational drought indicators to policy actions in regulated water supply systems is presented. The methodology is based on the evaluation of the probability of not being able to satisfy system demands for a given time horizon. A simplified model of every water resources system in the basin was built to evaluate the threshold of reservoir volume that is required to overcome the drought situation without deficit. For each reservoir level, a set of policy actions is proposed with the goal of guaranteeing essential demands during drought conditions. The methodology was validated with a simulation of system behavior for 60 years of historic streamflow series, finding acceptable results in most systems. [ABSTRACT FROM AUTHOR]