Modeling water resources management at the basin level: review and future directions

Water quality / Water resources development / Agricultural production / River basin development / Mathematical models / Simulation models / Water allocation / Policy / Economic aspects / Hydrology / Reservoir operation / Groundwater management / Drainage / Conjunctive use / Surface water / GIS / Decision support systems / Optimization methods / Water supply

Conjunctive use of surface water and groundwater with quality considerations

Deterministic models of conjunctive surface and groundwater management aren’t much more complicated than typical groundwater-only management models under simple assumptions. However, when water quality problems exist, the fact that there are two alternative sources of water gains a new significance, as there is no guarantee that they will be of comparable quality. Thus the benefit from using one unit of surface water may not be the same as that of one unit of groundwater. This paper analyses the implications of considering a conjunctive ground and surface water system where water quality varies according to source, with and without uncertainty in hydrological parameters.

Use of habitat suitability modeling in the integrated urban water system modeling of the Drava River (Varazdin, Croatia)

The development of practical tools for providing accurate ecological assessment of rivers and species conditions is necessary to preserve habitats and species, stop degradation and restore water quality. An understanding of the causal mechanisms and processes that affect the ecological water quality and shape macroinvertebrate communities at a local scale has important implications for conservation management and river restoration. This study used the integration of wastewater treatment, river water quality and ecological assessment models to study the effect of upgrading a wastewater treatment plant (WWTP) and their ecological effects for the receiving river. The WWTP and the water quality and quantity of the Drava river in Croatia were modelled in the software WEST. For the ecological modeling, the approach followed was to build habitat suitability and ecological assessment models based on classification trees. This technique allows predicting the biological water quality in terms of the occurrence of macroinvertebrates and the river status according to ecological water quality indices. The ecological models developed were satisfactory, and showed a good predictive performance and good discrimination capacity. Using the integrated ecological model for the Drava river, three scenarios were run and evaluated. The scenario assessment showed that it is necessary an integrated approach for the water management of the Drava river, which considers an upgrading of the WWTP with Nitrogen and Phosphorous removal and the treatment of other diffuse pollution and point sources (including the overflow of the WWTP). Additionally, if an increase in the minimum instream flow after the dams is considered, a higher dilution capacity and a higher self-cleaning capability could be obtained. The results proved that integrated models like the one presented here have an added value for decision support in water management. This kind of integrated approach is useful to get insight in aquatic ecosystems, for assessing investments in sanitation infrastructure of urban wastewater systems considering both, the fulfilling of legal physical chemical emission limits and the ecological state of the receiving waters

Valuing trout angling benefits of water quality improvements while accounting for unobserved lake characteristics: An application to the Rotorua Lakes

Trout angling is one of the most popular water-based recreational activities in the Rotorua Lakes. Despite the high demand for trout angling and other recreational purposes, water quality in some of these lakes has been declining over the past decades and initiatives to try to restore the lakes are underway. To compliment these efforts, this study uses the travel cost random utility models to explore how changes in water quality would impact upon angler’s choice of fishing destinations. The welfare impacts due to water quality changes and possible lake closures are also explored. These findings highlight the importance of discrete choice random utility models as a policy decision making tool for recreational-based natural resource managers in New Zealand. Additionally, this study represents one of the unique cases in travel cost random utility applications that accounts fully for unobserved site effect

Application of Change-Point Detection to a Structural Component of Water Quality Variables

In this study, methodologies were developed in statistical time series models, such as multivariate state-space models, to be applied to water quality variables in a river basin. In the modelling process it is considered a latent variable that allows incorporating a structural component, such as seasonality, in a dynamic way and a change-point detection method is applied to the structural component in order to identify possible changes in the water quality variables in consideration

Selecting relevant predictors: impact of variable selection on model performance, uncertainty and applicability of models in environmental decision making

One of the crucial steps when developing models is the selection of appropriate variables. In this research we assessed the impact variable selection on the model performance and model applicability. Regression trees were built to understand the relationship between the ecological water quality and the physicalchemical and hydromorphological variables. Different model parameterizations and three combinations of explanatory variables were used for developing the trees. Once constructed, they were integrated with the water quality model (PEGASE) and used to simulate the future ecological water quality. These simulations were summarized per combination of explanatory variables and compared. Three key messages summarize our conclusions. First, it was confirmed that different parameterizations alter the statistical reliability of the trees produced. Secondly, it was found that statistical reliability of the models remained stable when different combinations of explanatory variables were implemented. The determination coefficient (R²) ranged from 0.68 to 0.86; Kappa statistic (K) ranged from 0.15 and 0.46; and the percentage of Correctly Classified Instances (CCI) from 33 to 59%. Thirdly, when applying the models on an independent dataset consisting of future physical-chemical water quality data, different conclusions may be taken, depending on the combination of variables used

Groundwater research and management: integrating science into management decisions. Proceedings of IWMI-ITP-NIH International Workshop on "Creating Synergy Between Groundwater Research and Management in South and Southeast Asia," Roorkee, India, 8-9 February 2005

Groundwater management / Governance / Groundwater development / Artificial recharge / Water quality / Aquifers / Groundwater irrigation / Water balance / Simulation models / Watershed management / Water harvesting / Decision making / South East Asia / Bangladesh / China / India / Nepal / Pakistan / Syria

The potential role of socio-hydrological models for participatory water governance in Burkina Faso

Halting and reversing water quality degradation is a major global concern. The variety of needs and priorities placed on water resources make the issue of water pollution multifaceted and complex. Addressing water quality management requires an approach that can tackle the diversity of requirements and concerns to achieve effective strategies. In Burkina Faso, stakeholder participation plays an important role in effective catchment management. The Participatory Water Governance Project in Rural Burkina Faso has developed support strategies to strengthen the capacity of local-level Water User Committees. Research conducted by TU Wien (Technical University Vienna) and International Water Management Institute (IWMI) aims to support the project by exploring the potential role of socio-hydrological models in water management decision making. The areas around the River Kou and Bapla Reservoir were the focus for this part of the study. The specific question addressed by TU Wien was: can a socio-hydrological model be developed that accurately captures the relationships between people and water quality in the study area

The Role of Water Quality Perceptions in Modeling Lake Recreation Demand

Recreation demand models typically incorporate measures of the physical attributes of recreational sites; e.g., Secchi depth or phosphorous levels in case of water quality. Moreover, most studies show that individuals do respond to these physical characteristics in choosing where to recreate. However, the question remains as to whether the available physical measures accurately capture individual perceptions of water quality and if there is a additional role to be played by elicited perception measures in modeling recreation demand. In this paper, we use data from the 2004 Iowa Lakes Survey to model recreation demand as a function of both the physical water quality at 131 lakes in the state and household perceptions of lake water quality. In general, water quality perceptions are correlated with the available physical measures, but not perfectly so, and both actual and perceived water quality are found to significantly impact recreational site choice.

Socioeconomic Factors and Water Quality in California

We investigate the relationships between water quality and socioeconomic factors in California at the county level for the years 1993 to 2006 using 24 water quality indicators coming from seven different types of water bodies. We estimate these relationships using three classes of models: the traditional per capita income-pollution level - Environmental Kuznets Curve (EKC) - specifications, a more inclusive model containing main socioeconomic variables such as agricultural intensity, land use, ethnic composition, population density and educational attainment, and a model that includes the socioeconomic variables while accounting for spatial correlations too. For most water quality indicators, we do not find support for EKC specifications. For pollutants like phosphorus and total suspended solids, the level of agricultural activity is a significant determinant of water quality in California, but for other surface water pollutants commonly considered agricultural pollutants, such as ammonia and nitrate, the level of agricultural activity is not statistically significant. We find that education, ethnic composition, age structure, land use, population density, and water area are all significantly correlated with various indicators of water quality.Water Quality Indicators, Socioeconomic Variables, EKC, Agriculture, Industry