Nicholas Kouwen

Field estimation of the biomechanical properties of grass

Two methods for the field evaluation of vegetative stiffness are presented and compared. These methods enable the determination of the flow capacity of a vegetative channel. The dimensional analysi...

Nonpoint source pollution: a distributed water quality modeling approach.

A distributed water quality model for nonpoint source pollution modeling in agricultural watersheds is described in this paper. A water quality component was developed for WATFLOOD (a flood forecast hydrological model) to deal with sediment and nutrient transport. The model uses a distributed group response unit approach for water quantity and quality modeling. Runoff, sediment yield and soluble nutrient concentrations are calculated separately for each land cover class, weighted by area and then routed downstream. With data extracted using Geographical Information Systems (GIS) technology for a local watershed, the model is calibrated for the hydrologic response and validated for the water quality component. The transferability of model parameters to other watersheds, especially those in remote areas without enough data for calibration, is a major problem in diffuse modeling. With the connection to GIS and the group response unit approach used in this paper, model portability increases substantially, which will improve nonpoint source modeling at the watershed-scale level.

Flow Resistance in Vegetated Waterways

ABSTRACT Anew method to determine the flow capacity of a vegetated channel is presented. The method uses the vegetations length and stiffness as parameters. Graphs of field data of Mannings n versus the product VR, velocity times hydraulic radius, can be accurately repro-duced. A table of stiffness values for various types of veg-etation for which flow data were available is included. It is shown that the n —VR method of channel design cur-rently in use is based on the correct premise that n is a function of VR regardless of the relative values of V and R. The limitations of the n —VR method are stated. The advantage of the new method is that it is a numerical method which can be easily incorporated in computer programs for other purposes such as backwater or rout-ing models.

WindVOiCe, a Self-Reporting Survey: Adverse Health Effects, Industrial Wind Turbines, and the Need for Vigilance Monitoring

Industrial wind turbines have been operating in many parts of the globe. Anecdotal reports of perceived adverse health effects relating to industrial wind turbines have been published in the media and on the Internet. Based on these reports, indications were that some residents perceived they were experiencing adverse health effects. The purpose of the WindVOiCe health survey was to provide vigilance monitoring for those wishing to report their perceived adverse health effects. This article discusses the results of a self reporting health survey regarding perceived adverse health effects associated with industrial wind turbines.

Gas migration and vent design at landfill sites

AbtractA finite element model has been developed to simulate the migration of gases in soil from a buried source such as a landfill. Using quadratic elements, the diffusion convection equation coupled with the mass conservation equation of a binary mixture of gases is solved under a combination of Dirichlet, Neumann and flux type of boundary conditions. The model is compared with an analytical solution and a set of field measurements. The model is used to display the influence of seasons on the migration of gases. The effectiveness of venting trenches in containing such migrations is examined and a method for determination of trench depth is presented.

Texture processing of synthetic aperture radar data using second-order spatial statistics

Abstract A method is presented for generating second-order spatial statistics (texture) from digital image data using the neighboring gray-level dependence matrix (NGLDM). Texture processing of a high-resolution airborne synthetic aperture radar image in an agricultural environment improved crop classification over the raw data. Classification of the large-number emphasis feature, based on the NGLDM (window size = 11 × 11, α = 24 and β = 1), showed a 30.5% improvement in validation accuracy over the tonal data.

Modelling methane migration in soil

Abstract Based on Bear-Bachmat porous medium model, the governing equations for the migration of gases through soil from a buried source are presented. A finite element solution system for the equations is developed. The resulting model is capable of incorporating medium anistropy and inhomogeneity in an axisymmetric configuration. The model has facilities for including time-varying fluid properties and boundary conditions. Convergence of the solution is examined. Potential applications for the modelling of gas migration from waste burial sites and the evaluation of control mechanisms are discussed.

Water Quality Model Integration in a Decision Support System

This paper describes an integral system to model nonpoint source pollution in surface waters. Diffuse pollution models were included in a Spatial Decision Support System (SDSS) with a unique platform, common interfaces and Geographic Information System (GIS) capabilities. This consists of pre- and post-processing tools, model control and sensitivity analysis for the parameters in the models. Particularly, the construction of the interface for WATFLOOD (flood forecast hydrological model) and its link with the decision support system RAISON (Regional Analysis by Intelligent Systems On microcomputers) is presented. A water quality component was coupled to the model in order to deal with sediment and nutrient transport. Previous work with the AGNPS (Agricultural Non-Point Source) model is used for comparison with the results from the water quality component coupled to the WATFLOOD model.

Particulate transport in a porous media under non-linear flow conditions

Results of an experimental program concerning the movement of particulates in a porous medium under conditions of non-linear flow are presented. The results are compared with the limited existing data and a model developed by Sakthivadivel [8] for linear flow conditions. Modifications were required to this model to allow it to be used under the present conditions. Examination of the results suggested an alternative transport model using suitable dimensionless parameters. This model is shown to be superior to the existing model.

Integrating Logistical and Technical Criteria into a Multiteam, Competitive Watershed Model Ranking Procedure

AbstractA systematic and holistic watershed model comparison and selection process, integrating a full range of relevant criteria, is illustrated here. The process consists of screening for a set of candidate models on the basis of prerequisite model attributes; assessing hydrologic simulation performance using various conventional statistical metrics; assessing operational logistics performance, reflecting somewhat subjective but centrally important issues around relative feasibility and suitability of candidate models in the intended context of use; and integrating the hydrologic and operational performance results, which are each evaluated using a weighted-matrix approach, into a single coherent and comprehensive ranking system. The process was applied to evaluation of watershed models for operational hydroelectric inflow forecasting in British Columbia, Canada. An important feature of the study was its horse-race project management approach, involving a supervised competition between expert teams usin...