Daniel P. Ames

HydroDesktop: Web services-based software for hydrologic data discovery, download, visualization, and analysis

Discovering and accessing hydrologic and climate data for use in research or water management can be a difficult task that consumes valuable time and personnel resources. Until recently, this task required discovering and navigating many different data repositories, each having its own website, query interface, data formats, and descriptive language. New advances in cyberinfrastructure and in semantic mediation technologies have provided the means for creating better tools supporting data discovery and access. In this paper we describe a freely available and open source software tool, called HydroDesktop, that can be used for discovering, downloading, managing, visualizing, and analyzing hydrologic data. HydroDesktop was created as a means for searching across and accessing hydrologic data services that have been published using the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS). We describe the design and architecture of HydroDesktop, its novel contributions in web services-based hydrologic data search and discovery, and its unique extensibility interface that enables developers to create custom data analysis and visualization plug-ins. The functionality of HydroDesktop and some of its existing plug-ins are introduced in the context of a case study for discovering, downloading, and visualizing data within the Bear River Watershed in Idaho, USA.

Technical assessment and evaluation of environmental models and software

This letter details the collective views of a number of independent researchers on the technical assessment and evaluation of environmental models and software. The purpose is to stimulate debate and initiate action that leads to an improved quality of model development and evaluation, so increasing the capacity for models to have positive outcomes from their use. As such, we emphasize the relationship between the model evaluation process and credibility with stakeholders (including funding agencies) with a view to ensure continued support for modelling efforts.Many journals, including EM&S, publish the results of environmental modelling studies and must judge the work and the submitted papers based solely on the material that the authors have chosen to present and on how they present it. There is considerable variation in how this is done with the consequent risk of considerable variation in the quality and usefulness of the resulting publication. Part of the problem is that the review process is reactive, responding to the submitted manuscript. In this letter, we attempt to be proactive and give guidelines for researchers, authors and reviewers as to what constitutes best practice in presenting environmental modelling results. This is a unique contribution to the organisation and practice of model-based research and the communication of its results that will benefit the entire environmental modelling community. For a start, our view is that the community of environmental modellers should have a common vision of minimum standards that an environmental model must meet. A common vision of what a good model should be is expressed in various guidelines on Good Modelling Practice. The guidelines prompt modellers to codify their practice and to be more rigorous in their model testing. Our statement within this letter deals with another aspect of the issue - it prompts professional journals to codify the peer-review process. Introducing a more formalized approach to peer-review may discourage reviewers from accepting invitations to review given the additional time and labour requirements. The burden of proving model credibility is thus shifted to the authors. Here we discuss how to reduce this burden by selecting realistic evaluation criteria and conclude by advocating the use of standardized evaluation tools as this is a key issue that needs to be tackled.

Evaluation and Implementation of the OGC Web Processing Service for Use in Client-Side GIS

The Open Geospatial Consortium Web Processing Service specification is intended as a solution for creating and distributing web-based functions. This paper seeks to evaluate the WPS specification with respect to feasibility and utility, to identify areas for improvement, and to provide a demonstration implementation approach including a client-side tool and a server-side wrapping technique for exposing geoprocessing functionality through WPS using an asynchronous approach. Challenges with the WPS specification, some of which are already being addressed in the newest WPS revisions, are discussed together with proposed solutions. Several potential enhancements to the WPS proposal are introduced and considered, including a mechanism to guide client applications in prompting for correct data and a means to list the data available on a server.

What is the effect of LiDAR-derived DEM resolution on large-scale watershed model results? ☆

This paper examines the effect of raster cell size on hydrographic feature extraction and hydrological modeling using LiDAR derived DEMs. LiDAR datasets for three experimental watersheds were converted to DEMs at various cell sizes. Watershed boundaries and stream networks were delineated from each DEM and were compared to reference data. Hydrological simulations were conducted and the outputs were compared. Smaller cell size DEMs consistently resulted in less difference between DEM-delineated features and reference data. However, minor differences been found between streamflow simulations resulted for a lumped watershed model run at daily simulations aggregated at an annual average. These findings indicate that while higher resolution DEM grids may result in more accurate representation of terrain characteristics, such variations do not necessarily improve watershed scale simulation modeling. Hence the additional expense of generating high resolution DEMs for the purpose of watershed modeling at daily or longer time steps may not be warranted.

Watershed model parameter estimation and uncertainty in data-limited environments

Parameter uncertainty and sensitivity for a watershed-scale simulation model in Portugal were explored to identify the most critical model parameters in terms of model calibration and prediction. The research is intended to help provide guidance regarding allocation of limited data collection and model parameterization resources for modelers working in any data and resource limited environment. The watershed-scale hydrology and water quality simulation model, Hydrologic Simulation Program - FORTRAN (HSPF), was used to predict the hydrology of Lis River basin in Portugal. The model was calibrated for a 5-year period 1985-1989 and validated for a 4-year period 2003-2006. Agreement between simulated and observed streamflow data was satisfactory considering the performance measures such as Nash-Sutcliffe efficiency (E), deviation runoff (Dv) and coefficient of determination (R2). The Generalized Likelihood Uncertainty Estimation (GLUE) method was used to establish uncertainty bounds for the simulated flow using the Nash-Sutcliffe coefficient as a performance likelihood measure. Sensitivity analysis results indicate that runoff estimations are most sensitive to parameters related to climate conditions, soil and land use. These results state that even though climate conditions are generally most significant in water balance modeling, attention should also focus on land use characteristics as well. Specifically with respect to HSPF, the two most sensitive parameters, INFILT and LZSN, are both directly dependent on soil and land use characteristics. HSPF calibration/validation study on data limited watersheds.HSPF water balance parameters sensitivity analysis reported similar results for different watershed studies.The effect of model uncertainty is determined by the threshold value established to obtain the confidence interval.Accuracy of climate and land use data is very important for model performance.

Short communication: Estimation of stream channel geometry in Idaho using GIS-derived watershed characteristics

This paper describes estimation of stream channel geometry with multiple regression analysis of GIS-derived watershed characteristics including drainage area, catchment-averaged precipitation, mean watershed slope, elevation, forest cover, percent area with slopes greater than 30 percent, and percent area with north-facing slopes greater than 30 percent. Results from this multivariate predictor method were compared to results from the traditional single-variable (drainage area) relationship for a sample of 98 unregulated and undiverted streams in Idaho. Root-mean-squared error (RMSE) was calculated for both multiple- and single-variable predictions for 100 independent, random subsamples of the dataset at each of four different subsample levels. The multiple-variable technique produced significantly lower RMSE for prediction of both stream width and depth when compared to the drainage area-only technique. In the best predictive equation, stream width depended positively on drainage area and mean watershed precipitation, and negatively on fraction of watershed consisting of north-facing slopes greater than 30%. Stream depth depended positively on drainage area and precipitation, and negatively on mean watershed elevation. Our results suggest that within a given physiographic province, multivariate analysis of readily available GIS-derived watershed variables can significantly improve estimates of stream width and depth for use in flow-routing software models.

HydroServer Lite as an open source solution for archiving and sharing environmental data for independent university labs

Abstract Managing, archiving, and sharing large amounts of data are essential tasks in ecological laboratories, and detailed data management plans are now required by major funding agencies. Many independent research labs may lack the technical or financial resources needed to support some of the more comprehensive data management solutions that have become available. In this paper we describe an open-source solution to data management, archiving, and sharing that can be implemented and customized by someone with limited computer programming experience using free software and standardized web services. This software, HydroServer Lite, is a light-weight database and data management web-based application that integrates with and makes data available on a large data sharing network developed by the Consortium of Universities for the Advancement of Hydrologic Sciences, Inc. (CUAHSI). The CUAHSI Hydrologic Information System facilitates data sharing through a network of local HydroServers that are registered with the central registry. Each HydroServer may contain a variety of ecological and climate data, stored in a standardized relational database model. Someone searching for data that are registered in the central registry can query the network by source, location, variable type, and dates. These data can be downloaded from the local HydroServer to a computer in an office or lab where they can be manipulated and analyzed without compromising the data in the archives. We offer this HydroServer Lite case study as a possible solution for independent research laboratories looking for a data management system that requires little technical expertise or initial cost to set up.

Large-scale analytical water quality model coupled with GIS for simulation of point sourced pollutant discharges

Mathematical modeling is an important tool for water quality studies, and the integration of water quality models with geographic information systems (GIS) is very useful for information extraction and for results interpretation. In this context, this work presents the development of a water quality model coupled with GIS (MapWindow GIS) for representing impacts of point-sourced pollutants released with distinct durations under different flow scenarios, allowing a systemic view of the entire basin, and capable of being used with low data availability. The model is called SIAQUA-IPH and uses a pollutograph convolution scheme to represent multiple discharges and confluences in the basin, based on analytical solutions of the longitudinal advection-dispersion equation. Operational tests presented a full operational performance from all technical solutions adopted, and a representation of plumes considered satisfactory in comparison to observations. Additionally, a simple sensitivity analysis is presented, that gives useful insights about the model application. Water quality decision support model fully coupled with an open GIS.Represents pollutants released with distinct durations using a convolution schema.Useful at low data availability and large scale basins, common on Brazilian cases.Results are compared with observed data and critically analyzed.Considerations are presented about the adopted modeling approach usage.

A Bayesian Decision Network Engine for Internet-Based Stakeholder Decision-Making

In this paper, we present an Internet-based, Bayesian Decision Network engine to aid watershed stakeholders in collaborative decision-making. Recent years have seen an increased emphasis on including all affected parties in the process of making water resources and water quality management decisions (as in the TMDL program). Given the complexity of the models and data analysis tools that are typically employed by engineers and scientists in watershed studies, meaningful communication with stakeholders can be a daunting task. In our experience, stakeholders are often skeptical of model and data analysis results because of the inherent uncertainty associated with these methods. Because of this, a stakeholder may be more likely to accept results presented in the form of a probability distribution of potential outcomes, than a single predicted result. Additionally, if model predictions are mapped into the likelihood of realizing tangible and intangible benefits, stakeholders have a means whereby to evaluate the anticipated results. Bayesian Decision Network (BDNs) are presented here as a useful tool for diagramming the decision process; for holding relationships between variables; and for analyzing the anticipated effects of management decisions while explicitly accounting for the associated uncertainties. An Internet-based application for employing BDNs in watershed decision-making is described with a demonstration application from the East Canyon watershed in Utah.

Chapter Ten Free and Open Source Geospatial Tools for Environmental Modelling and Management

Abstract Geospatial (geographical) software systems (GIS) are used for creating, viewing, managing, analysing and utilising geospatial data. Geospatial data can include socioeconomic, environmental, geophysical, and technical data about the Earth and societal infrastructure and it is pivotal in environmental modelling and management (EMM). Desktop, web-based, and embedded geospatial systems have become an essential part of EMM, providing pre- or post-processing of geospatial data, analysis and visualisation of results or a graphical user interface (GUI). Many local, regional, national, and international efforts are underway to create geospatial data infrastructures and tools for viewing and using geospatial data. When environmental attribute data is linked to these infrastructures, powerful tools for environmental management are instantly created. The growing culture of free/libre and open source software (FOSS) provides an alternative approach to software development for the field of GIS (FOSS4G). To provide an overview of FOSS4G for EMM, we analyse platforms, software stacks, and EMM workflows. In the FOSS world the barriers to interoperability are low and thus the software stack tends to be thicker than in the proprietary platform. The FOSS4G world thrives on the evolution of software stacks and platforms. We provide examples of software stacks built from current FOSS4G that support EMM workflows and highlight the advantages of FOSS4G solutions including opportunities to redistribute resulting modelling tools freely to end-users and to support general goals of openness and transparency with respect to modelling tools.