tRIBS model
tRIBS Research Description


tRIBS Model
TIN-based Real-Time Basin Simulator (tRIBS) Distributed Hydrologic Model

The TIN-based Real-Time Integrated Basin Simulator (tRIBS) is a physically-based, distributed hydrologic model developed at the Ralph M. Parsons Laboratory, Massachusetts Institute of Technology. The model emphasizes the dynamic relationship between a partially saturated vadose zone and the land surface response to the continuous storm and interstorm cycle. This is performed by tracking the evolution of moisture fronts within a computational element in relation to the water table depth position. One-dimensional infiltration in the surface normal direction is redistributed by both the lateral fluxes in the vadose zone and in the phreatic aquifer during storm and interstorm periods. By modeling these detailed processes, tRIBS is capable of producing runoff through a number of generation mechanisms including infiltration-excess, saturation from below and perched saturation-excess runoff. In combination, these processes allow tRIBS to model the development of partial contributing areas within the basin. Currently, the runoff produced from these areas is routed to the outlet using a simplified scheme that allows non-linearity in the routing through the channel network.

In its early developmental stages, tRIBS was an event-based model operating on a raster grid cell computational domain (RIBS). Recently, however, the model has been extended to perform on a continuous basis with the addition of a new infiltration scheme for multiple storm events and hydrologic redistribution during interstorm periods due to groundwater flow and evapotranspiration demand. In addition, developments in TIN-based terrain modeling have also been incorporated into the model by restructuring the computational architecture. No longer bound to a raster grid, the computational domain is adjusted to better fit the terrain, allowing for significant savings in computation demand. In this framework, the voronoi cell serves as the element for hydrologic modeling.

In its current state, tRIBS is capable of using the spatially distributed terrain data to their fullest capacity while maintaining the efficiency required for treating larger watersheds. In addition, the model is capable of using other spatially distributed descriptors of the basin properties, specifically the soil type, vegetation and land cover data. Coupled with the ability to ingest precipitation estimates and forecasts from NEXRAD-based maps, tRIBS is able to take advantage of driving reasons for utilizing radar rainfall data: spatial coverage and temporal/spatial variability.