A regional water quality model designed for a range of users and for retrofit and re-use

We discuss the motivations for, and software design concepts underpinning, the development of a regional water quality model. The Environmental Management Support System (EMSS) was developed to predict daily fluxes of runoff, total suspended sediment, total nitrogen and total phosphorous through a large-scale river network. It was built using a custom environmental modelling framework called Tarsier, founded on the Borland C++ Builder rapid application development environment. Three autonomous models are integrated within the EMSS, but are loosely coupled so that alternative models could be retrofitted into the system if desired. The three models share common data handling and visualisation routines resident in the Tarsier modelling environment and used in other modelling applications. The EMSS was designed for use by a range of stakeholders with varying levels of computer and technical proficiency. To satisfy their varying needs, we built three different interfaces, suited to ‘expert’, ‘intermediate’ and ‘basic’ users. The interfaces for the latter two groups were developed using interface prototyping methods, resulting in software that suited the user requirements. The object-oriented design employed in the coding of the EMSS has enhanced the extendibility and re-useability of the software. The EMSS development was part of a larger hydrologic modelling initiative aimed at reducing duplication in model building and standardising approaches to model design and delivery. The lessons learned during development of the EMSS have informed our future model development strategy

Runoff and sediment generation on bench -terraced hillsides: measurements and up-scaling of a field-based model

Despite widespread bench-terracing, stream sediment yields from agricultural hillsides in upland West Java remain high. We studied the causes of this lack of effect by combining measurements at different spatial scales using an erosion process model. Event runoff and sediment yield from two 4-ha terraced hillside subcatchments were measured and field surveys of land use, bench-terrace geometry and storage of sediment in the drainage network were conducted for two consecutive years. Runoff was 3.0-3-9% of rainfall and sediment yield was 11-30 t h

Comparing modelling frameworks : a workshop approach

Of concern to the environmental modelling community is the proliferation of individual, and individualistic, models and the time associated with common model development tasks such as data transformation, coding of models, and visualisation. One way of addressing this problem is the adoption of modelling frameworks. These frameworks, or environments, support modular model development through provision of libraries of core environmental modelling modules, as well as reusable tools for data manipulation, analysis and visualisation. Such frameworks have a range of features and requirements related to the architecture, protocols and methods of operation, and it is difficult to compare the modelling workload and performance of alternative frameworks without using them to undertake identical, or similar modelling tasks. This paper describes the outcomes of a workshop to compare three frameworks - the Spatial Modelling Environment (SME), Tarsier and the Integrated Component Modelling System (ICMS). A simple environmental problem linking hillslope flow and soil erosion processes with a receiving water store was designed and then implemented in the three frameworks. It was found that the SME and Tarsier contained many components well suited to handling complex spatial and temporal models, with ICMS being an integrated framework tailored for smaller scale problems. Of the three tested frameworks, the SME proved superior in supporting problem description, Tarsier provided more flexibility in linking and validating the model components, and ICMS served as an effective prototyping tool. The test problem, and associated data and parameters, are described in detail to allow others to undertake this test.No Full Tex

Avaliação da capacidade de infiltração de solos submetidos a diferentes tipos de manejo Evaluation of the infiltration capacity of soils under ferent types of management

O manejo inadequado da vegetação e do solo leva a mudanças físicas que afetam a recarga de aquíferos. A Chapada do Araripe possui centenas de fontes que jorram na encosta; porém, há indícios de redução de vazões. Neste trabalho foi estudada a capacidade de infiltração de solos submetidos a diferentes tipos de manejo florestal na Chapada. Amostras de solos de 21 localidades foram ordenadas em quatro grupos. O Grupo 1, de áreas de vegetação preservada e os demais de áreas antropizadas. Observou-se que a umidade e capacidade de infiltração apresentaram boa correlação linear com a matéria orgânica; a umidade média do Grupo 1, no período seco, foi superior à dos demais grupos mesmo no período chuvoso; as áreas antropizadas apresentaram baixo conteúdo de matéria orgânica, umidade e baixa capacidade de infiltração, indicando modificação na estrutura do solo capaz de reduzir a recarga.<br>Inadequate vegetation and soil management leads to physical changes that affect aquifer recharge. The Araripe Plateau feeds an elevated number of springs on its northern slope; however, there are indications that their yield is decreasing. Through this research, it was studied the infiltration capacity of soils under different types of management. Soil samples from 21 sites were grouped into four groups. Group 1 represents areas of preserved vegetation, the others, anthropized ones. It was observed that soil moisture and infiltration capacity are linearly well correlated with organic matter; mean soil moisture during the dry season was significantly higher for Group 1 than for the other groups, even during the rainy season and anthropized areas show low organic matter contents, soil moisture, and infiltration capacity, indicating modifications in the soil's structure that reduce aquifer recharge