David A. Swayne

Environmental Software Systems

Environmental Software Systems , Environmental Software Systems , کتابخانه دیجیتال جندی شاپور اهواز

Multi-objective modelling and decision support using a Bayesian network approximation to a non-point source pollution model

Abstract This paper illustrates a methodology to create a multi-objective modelling system using Bayesian probability networks to emulate the behaviour of an environmental model that was originally intended for the purpose of analyzing a problem – non-point source pollution in our example. Modelling systems frequently pertain to a single domain (physical or chemical process modelling, hydrology or combinations) to simulate a process in nature such as pollution transport or the production of food or manufactured goods. Economic or other effects are treated separately, or handled in a non-interactive manner. Side-effects of agro-industrial processes, or gains/losses from production enterprises, are generally modelled separately without the ability to examine trade-offs or alternatives. Multi-objective modelling attempts to work in more than one problem domain through decision theoretical principles. Such treatments are designed to couple production and waste systems, to quantify the economic cost of remediation. This model will demonstrate such an application, from the data acquisition, model calibration to the hypothesis testing, for a non-point source pollution model. This will be combined with a simplified net revenue model based on crop rotations typically found in Southern Ontario, Canada, using realistic economic data obtained from agricultural operations similar to those found in this region. We will demonstrate that multi-year analyses are possible with such a system.

Multi-model integration in a decision support system: a technical user interface approach for watershed and lake management scenarios

Abstract Computer simulations using mathematical models provide useful tools to investigate different scenarios based on watershed management strategies and environmental conditions. They often require the combined knowledge of meteorological, hydrological, hydrodynamic and biochemical processes in air, soil and water. While existing models for individual processes are available, computational issues (e.g. software compatibility and consistency of model assumptions) on linking and integrating these models are challenging. To resolve these issues, we propose using a technical user interface approach based on expert system technologies that provide intelligent access to databases, models, scenarios and decision support output. As an example, we applied the multi-model integration approach to a watershed management study on Lake Seymour, BC, Canada, where sediment erosion due to precipitation events or forest fires may lead to concerns of high turbidity conditions in a reservoir.

Redesigning introductory computer programming with HTML, JavaScript, and Java

In this paper we describe our experience in the design and teaching of a new evolutionary introductory programming course in a new Distributed Computing and Communications Systems Technology program at the University of Guelph-Humber. This course is evolutionary and innovative because it integrates the use of HTML, JavaScript, and Java in a one-semester introductory computer programming course. This is a marked departure from the use of a single conventional, general purpose, programming language such as Java or C++. The course is designed with two goals in mind: to improve the students experience in their first computer programming; and to achieve retention in the new program.

Integration of a Nonpoint Source Pollution Model with a Decision Support System

Abstract This paper is a progress report of an ongoing research project from which the expected final product will be an integral system to model nonpoint source pollution in surface waters. Diffuse pollution models will be included in a decision support system with a unique platform, common interfaces and GIS capabilities. This system will accommodate pre- and post-processing tools, model control and sensitivity analysis for the parameters in the models. Particularly, the construction of the interface for the AGNPS model and its link with the decision support system RAISON is presented. The model is described, including the input requirements, the development of tools and the procedures created to extract the necessary data from digital elevation model, soil type and landcover vectorized files.

A PROTOTYPE INFORMATION SYSTEM FOR WATERSHED MANAGEMENT AND PLANNING

Watershed management and planning requires a reliable information system for the storage and manipulation of data and knowledge for an integrative approach to solve environmental problems. An approach to develop such an information system is described, with the focus on the requirements both for data analysis and for knowledge processing. Examples based on the results of a prototype system for three different watershed studies are presented to demonstrate the representation and visualization of data and knowledge. While the prototype system is found to be viable, its usefulness depends on the ability to link with existing software systems and on the commitment of expert partners in the formulation of an accurate knowledge base for watershed management and planning.

Regional analysis of watershed acidification using the expert systems approach

Abstract This paper describes a workstation environment for the regional analysis by intelligent system on a microcomputer (RAISON) for studying watershed acidification and other environmental problems. Data is processed with a map-based query language and a spreadsheet paradigm. Spatial and temporal data retrieval is made possible for any chosen region and time frame, so that information on water, air and soil is combined in a number of watershed acidification models. A simple prototype expert system uses each of these models and determine which is the most appropriate according to a set of decision rules defined by the user. Based on the data from 53 watersheds in Southern Quebec, Canada, regionalization of the expert model to 91 watersheds is achieved by using a Monte Carlo procedure. A mean relative error of 19.1% is obtained by the Monte Carlo results when compared to observed data.

Assessment of the interaction between the Canadian Regional Climate Model and lake thermal-hydrodynamic models

This paper describes our preliminary assessment of the system requirements (data, interface and process) for implementation of terms describing lake effects in the Canadian Regional Climate Model. We demonstrate test results for one-dimensional (1-D) and three-dimensional (3-D) models for lake hydrodynamics that have been tested and prepared for interfacing with atmospheric circulation models. We discuss the use of a physical interface model, Canadian Land Surface Scheme (CLASS), that is under consideration for the air-water interface. Our preliminary assessment indicates that it is technically feasible to apply the combination of small shallow lake (slab) model, 1-dimensional vertical model and 3-dimensional circulation model (for very large lakes), together with the current land-air linkage used in regional climate modelling in Canada. Whether we can discern the necessary conditions for invoking each of the models to the lakes present in individual regional climate grid cells is still to be determined.

Watershed acidification models using the knowledge-based systems approach

Abstract This paper presents a novel approach to prediction of lake acidification. We use for illustration the Cation Denudation Rate (CDR) and the Trickle Down (TD) Acidification Models. Instead of selecting one model and discarding the other, we utilize each model in those cases where it is most applicable, an approach which requires both a quantitative and qualitative judgement or rules to choose the proper model. This model has been implemented in a workstation environment — RAISON Micro — which has been designed to facilitate automated model selection and analysis. We present the results of a preliminary test using the water chemistry data from 53 southern Quebec watersheds in Canada with 364 sampling stations. Statistical comparison with observed data was found to be more favourable than that for the individual models. The results are improved by the systems built-in facility to correct anomalous behavior in circumstances for which an incorrect model choice has been made in the absence of definitive knowledge. The uncertainties of the individual models and the combined model were found to be greater for higher SO 2 inputs but became smaller for reduced loads.

Watershed management modelling in Malawi: application and technology transfer

Abstract To study the possible impact on the Lake Malawi/Nyasa/Niassa water quality due to actions performed at the watershed level, a modelling project supported by the World Bank, was conducted by the United Nations University, the University of Waterloo and WL Delft Hydraulics to integrate physical and bio-chemical processes models in the lake and its basin which affect lake and river water quality. The purpose of the integration of different models was to provide a set of tools in order to analyze the impact on the lake due to actions performed in the watershed. In this paper, we present the watershed and lake box models integration and a case application to find how agricultural practices and deforestation may impact on the water quality of rivers and streams which will then lead to changes in the nutrient loading to the lake.