Development of a Distributed Watershed Contaminant Transport, Transformation and Fate (CTT&F) Sub-Module for Military Installations

See also ADM002075. Presented at the Army Science Conference (25th) held in Orlando, FL on 27-30 November 2006. The original document contains color images.

Many U.S. Department of Defense installations contain soil, sediment, surface water, and groundwater environments contaminated with explosives and energetics. Modeling as part of watershed management to meet water quality goals is not new but most current models were developed and tested two decades ago. Watershed models are largely confined to lumped and semi-distributed surface water simulation. Models that reflect hydrologic and aquatic impacts from military conditions are rare. Watershed models that enable diagnostic, predictive, and operational applications in conjunction with monitoring and data collection programs are virtually non-existent across the board and are urgently needed within the scientific and modeling communities. To meet this need a physically based, distributed source Contaminant Transport, Transformation and Fate (CTT&F) sub-module was developed by the U.S. Army Engineer Research and Development Center, to simulate point and non-point sources across a watershed. The model operates on a cell by cell basis. Soil types, land uses, and other hydrologic characteristics can be varied spatially among cells. Potential chemicals are routed through the cells from the watershed divide to the outlet. The distributed, process-oriented structure of the model can be used for identifying critical source areas of non-point sources within the watershed, and can give insight on both the persistence and fate of explosives. The expectation is that a model of this type is able to quantify transport and transformation of multiple contaminants and can facilitate the assessment of the fate of distributed sources and lead to better management of the watershed environment for military installations. CTT&F can be linked to any distributed hydrologic model, assuming the hydrologic model provides the required flow and sediment transport fluxes. The ability of the model to simulate explosives in watersheds is demonstrated by a test case study in the laboratory environment.