Domain-specific metaware for hydrologic applications

The DHARMA domain-specific middleware system is intended to allow hydrologic field engineers to tackle water-management problems on a scale previously impossible without sophisticated computational management systems. DHARMA provides automatic data acquisition via the Internet; data fusion from online, local, and cached resources; smart caching of intermediate results; parallel process execution; automatic transformation and piping of data between different hydrologic simulation models; and interfaces with existing metacomputing systems. Our target watershed model, WEPP, is limited to very small watersheds with current computer technology. A revolutionary change in hydrologic modelling on the watershed scale will be brought about by applying various watershed models to large watersheds, such as the Lake Decatur Watershed, which covers 925 square miles. Even with unlimited computing resources, the current version of WEPP could not be directly applied to mode the Lake Decatur Watershed because the current implementation of WEPP is limited to a maximum of 75 hillslopes. To address this issue, we have now integrated support for multiple simulation models in our software; for example, we can use WEPP to model individual hillslopes and another model, such as SITES, to model the connecting channels (reaches) and dams (structures), playing to the strengths of both models. In this article we discuss the evolving software architecture of DHARMA and its interaction with the Web and Grid infrastructures.