Parameterization of a Gridded Rainfall-Runoff Model for Southern Australia

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

State updating and calibration period selection to improve dynamic monthly streamflow forecasts for an environmental flow management application

Monthly to seasonal streamflow forecasts provide useful information for a range of water resource management and planning applications. This work focuses on improving such forecasts by considering the following two aspects: (1) state updating to force the models to match observations from the start of the forecast period, and (2) selection of a shorter calibration period that is more representative of the forecast period, compared to a longer calibration period traditionally used. The analysis is undertaken in the context of using streamflow forecasts for environmental flow water management of an open channel drainage network in southern Australia. Forecasts of monthly streamflow are obtained using a conceptual rainfall–runoff model combined with a post-processor error model for uncertainty analysis. This model set-up is applied to two catchments, one with stronger evidence of non-stationarity than the other. A range of metrics are used to assess different aspects of predictive performance, including reliability, sharpness, bias and accuracy. The results indicate that, for most scenarios and metrics, state updating improves predictive performance for both observed rainfall and forecast rainfall sources. Using the shorter calibration period also improves predictive performance, particularly for the catchment with stronger evidence of non-stationarity. The results highlight that a traditional approach of using a long calibration period can degrade predictive performance when there is evidence of non-stationarity. The techniques presented can form the basis for operational monthly streamflow forecasting systems and provide support for environmental decision-making.Matthew S. Gibbs, David McInerney, Greer Humphrey, Mark A. Thyer, Holger R. Maier, Graeme C. Dandy and Dmitri Kavetsk

Forecasting Chlorine Residuals in a Water Distribution System Using a General Regression Neural Network

Abstract: In a water distribution system (WDS), chlorine disinfection is important in preventing the spread of waterborne diseases. By strictly controlling residual chlorine throughout the WDS, water quality managers can ensure the satisfaction and safety of their customers. However, due to the travel time of water between the chlorine dosing point and any strategic monitoring points, water treatment plant (WTP) operators often receive information too late for their responses to be effective. Given the ability to forecast the chlorine residual at strategic points in a WDS, it would be possible to have superior control over the chlorine dose, thereby preventing incidents of under-and over-chlorination. In this research, a general regression neural network (GRNN) has been developed for forecasting chlorine residuals in the Myponga WDS to the south of Adelaide, South Australia, 24 hours in advance. A number of critical model issues are addressed including: selection of an appropriate forecasting horizon; division of the available data into subsets for modelling; and, the determination of the inputs that are relevant to the chlorine forecasts. In order to determine if the GRNN is able to capture any nonlinear relationships that may be present in the data set, a comparison is made between the GRNN model and a multiple linear regression (MLR) model. When tested on an independent validation set of data, the GRNN models were able to forecast chlorine levels to a high level of accuracy, up to 24 hours in advance. The GRNN also significantly outperformed the MLR model, thereby providing evidence for the existence of nonlinear relationships in the data set

Microsurgical third ventriculocisternostomy as an alternative to ETV: report of two cases

OBJECTIVE: To describe a microsurgical alternative to endoscopic third ventriculocisternostomy. METHODS: Two children with shunt-dependent hydrocephalus and multiple shunt revisions were considered candidates for third ventriculocisternostomy (TVS). Because of slit ventricles, an endoscopic approach was not possible and, therefore, both patients received a microsurgical TVS by a supraorbital approach. RESULTS: In both cases, microsurgical TVS was successful and the patients became shunt free. CONCLUSION: Microsurgical TVS by a supraorbital craniotomy is a viable alternative to endoscopic TVS in selected cases

Paradigm shift in hydrocephalus research in legacy of Dandy’s pioneering work: rationale for third ventriculostomy in communicating hydrocephalus

OBJECTIVE: This study aims to question the generally accepted cerebrospinal fluid (CSF) bulk flow theory suggesting that the CSF is exclusively absorbed by the arachnoid villi and that the cause of hydrocephalus is a CSF absorption deficit. In addition, this study aims to briefly describe the new hydrodynamic concept of hydrocephalus and the rationale for endoscopic third ventriculostomy (ETV) in communicating hydrocephalus. CRITIQUE: The bulk flow theory has proven incapable of explaining the pivotal mechanisms behind communicating hydrocephalus. Thus, the theory is unable to explain why the ventricles enlarge, why the CSF pressure remains normal and why some patients improve after ETV. HYDRODYNAMIC CONCEPT OF HYDROCEPHALUS: Communicating hydrocephalus is caused by decreased intracranial compliance increasing the systolic pressure transmission into the brain parenchyma. The increased systolic pressure in the brain distends the brain towards the skull and simultaneously compresses the periventricular region of the brain against the ventricles. The final result is the predominant enlargement of the ventricles and narrowing of the subarachnoid space. The ETV reduces the increased systolic pressure in the brain simply by venting ventricular CSF through the stoma. The patent aqueduct in communicating hydrocephalus is too narrow to vent the CSF sufficiently

Gendered self-views across 62 countries: A test of competing models

Social role theory posits that binary gender gaps in agency and communion should be larger in less egalitarian countries, reflecting these countries’ more pronounced sex-based power divisions. Conversely, evolutionary and self-construal theorists suggest that gender gaps in agency and communion should be larger in more egalitarian countries, reflecting the greater autonomy support and flexible self-construction processes present in these countries. Using data from 62 countries (N = 28,640), we examine binary gender gaps in agentic and communal self-views as a function of country-level objective gender equality (the Global Gender Gap Index) and subjective distributions of social power (the Power Distance Index). Findings show that in more egalitarian countries, gender gaps in agency are smaller and gender gaps in communality are larger. These patterns are driven primarily by cross-country differences in men’s self-views and by the Power Distance Index (PDI) more robustly than the Global Gender Gap Index (GGGI). We consider possible causes and implications of these findings.info:eu-repo/semantics/acceptedVersio

Solving the multi-period water distribution network design problem with a hybrid simulated anealling

This work presents an optimization technique based on Simulated Annealing (SA) to solve the Water Distribution Network Design problem, considering multi-period restrictions with time varying demand patterns. The design optimization of this kind of networks is an important issue in modern cities, since a safe, adequate, and accessible supply of potable water is one of the basic necessities of any human being. Given the complexity of this problem, the SA is improved with a local search procedure, yielding a hybrid SA, in order to obtain good quality networks designs. Additionally, four variants of this algorithm based on different cooling schemes are introduced and analyzed. A broad experimentation using different benchmark networks is carried out to test our proposals. Moreover, a comparison with an approach from the literature reveals the goodness to solve this network design problem.Fil: Bermudez, Carlos Alberto. Universidad Nacional de la Pampa. Facultad de Ingeniería; ArgentinaFil: Salto, Carolina. Universidad Nacional de la Pampa. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Minetti, Gabriela Fabiana. Universidad Nacional de la Pampa. Facultad de Ingeniería; Argentin