Doctor of Philosophy

dissertationWater resources are limited and disproportionately distributed in time and place. Moreover, complex interactions among different components of the water system, changes in population and urbanization growth rates, and climate change have increased the uncertainty influencing water resource planning. The ultimate question arising for water managers considering the complexity of water systems is how to determine if management strategies are effective and improve the performance of a water system. Generally, decision-makers assess the system’s condition based on a univariate measure of reliability or vulnerability. However, these measures do not deliver sufficient information, and present a limited view about the system’s performance. There is a known need to study water resources in an integrated fashion to effectively manage for the present and the future. In this dissertation, a new comprehensive integrated modeling and performance assessment framework is offered. First, a new approach is designed to assess vulnerability of a water system based on important factors including exposure, sensitivity, severity, potential severity, social vulnerability, and adaptive capacity. Then, instead of an individual metric, the joint probability distribution of reliability and vulnerability based on copula function is developed to estimate a new index, the Water System Performance Index (WSPI), to evaluate the reliability and vulnerability of a water system simultaneously. To test the effectiveness of the framework and demonstrate the advances of the new performance index, a practical application is conducted for the Salt Lake City Department of Public Utilities (SLCDPU) water system. For this purpose, an integrated water resource management (IWRM) model is developed using system dynamics approach for the case study. Management alternatives are incorporated into the model using a decision support tool designed for use by water managers and stakeholders. Results of the study show an inconsistency in the degree of vulnerability between traditionally used and the new vulnerability assessment approaches. The use of the integrated model and new vulnerability approach is also shown to provide more informative guidance for decision makers evaluating alternative management strategies during failure events. Furthermore, results illustrate the effectiveness of the WSPI to identify critical conditions when there is a need for a combined measure of performance. In terms of water management decision making, the final results of this dissertation indicate centralized water storage solutions improve water system performance better than rainwater harvesting for the Salt Lake City case study

Integrated Urban Water Resources Modeling In A Semi-Arid Mountainous Region Using A Cyber-Infrastructure Framework

Water resources management in cities is facing growing challenges related to increases in water demand, uncertain future climate variability, and conflicts related to water rights and access. Integrated water resource management (IWRM) is an inter-disciplinary framework which connects separated infrastructures and elements of a water resource system together which have dynamic interconnection. An IWRM process broadly involves water supply systems, stormwater management, wastewater collection, climate variables, groundwater and other water related sectors to solve the water and environmental problems. In this study, an integrated framework applying the GoldSim Monte-Carlo simulation software is presented to provide dynamic simulation of inter-related parts of an urban water system. The framework supports fast access and application of data resources, exchange of data among sub-models, and capacity to produce long-term simulations with sufficiently high spatial resolution to support urban water management research. Also parts of the framework are web-based interface, results analysis, and visualization tools. Working with local water managers the framework has been designed to provide specific and useful information for stakeholders, water managers and researchers to answer location-specific questions related to water availability, stormwater management, and other aspects. It also has the potential to provide exploratory opportunities for community and K-12 education. This paper describes the framework and presents an analysis of decentralized versus centralized urban water management solutions for the Salt Lake City metropolitan area in Utah, USA

Comparing spatial and temporal scales of hydrologic model parameter transfer: A guide to four climates of Iran

Simulating streamflow in ungauged catchments remains a challenging task in hydrology and increases the demand for regionalization studies worldwide. Here, we investigate the effect of three modes of parameter transfer, including temporal (transferring across different periods), spatial (transferring between same calibration periods but different sites), and spatiotemporal (transferring across both different periods and sites) on simulating streamflow using HBV conceptual rainfall-runoff model at 576 unregulated catchments throughout Iran (407,000 Km2). Our main conclusions are: (1) temporal mode shows the best performance, with the lowest decline in performance (median decline of 5.8%) as measured using the NSE efficiency metric, (2) difference between spatial and spatiotemporal options was negligible (median decline of 13.7% and 15.1% respectively), (3) all parameters are associated with some uncertainties and those related to runoff and snow components of the model are associated with the highest and lowest uncertainties, respectively, (4) overall, the model performance in arid regions is not as good as humid regions which confirmed that elevation and climate play a major role in parameter estimation in these areas, and (5) aridity and catchment elevation are two major controls on model transferability at regional (climate classes) and local (the whole country) scales. We also show that the superiority of the temporal mode is maintained with: (i) increasing spatial distance between gauged (donor) and ungauged (target) catchments, (ii) increasing time lag (10 years) between calibration and validation, and (iii) gradually increased time lags between calibration and validation. Our study suggest that spatiotemporal parameter transfer can be a reliable option for PUB studies and climate change-related studies, at least in wetter catchments. However, further research is needed to explore the complicated relationship between temporal and spatial aspects of hydrological variability