Welcome to the RAPID Hub!
The RAPID Hub is the go-to place for information about the Routing Application for Parallel computatIon of Discharge (RAPID). Enjoy!

The Routing Application for Parallel computatIon of Discharge (RAPID) is a river routing model. Given surface and groundwater inflow to rivers, this model can compute the flow and volume of water everywhere in river networks made out of many thousands of reaches. The design of RAPID allows it to be adapted to any river network, if given basic connectivity information. RAPID uses a matrix version of the Muskingum method, and has an automated parameter estimation procedure that allows finding optimal model parameters based on available gage measurements. This model uses the Fortran programming language and can be run on personal computers, as well as on massively-parallel supercomputers, with demonstrated fixed-size parallel speedup. RAPID has the ability to run and/or optimize model parameters on any subbasin included in its computing domain. If major man-made infrastructures are present on the river network, RAPID allows to easily substitute upstream flow measured by gages within its simulations of river flow and its optimization of parameters. If information concerning water withdrawals or return flows is available, RAPID can remove or add the corresponding flows from its computations as well. Detailed information on RAPID can be found in the related publications.

Development history
The development of RAPID started in September 2007 as Cédric David joined the Center for Geosciences at Mines Paristech (Ecole des Mines de Paris, France) for a 6-month visit. This model was originally developed as an alternative to the river routing scheme of SIM-France, the operational hydro-meteorological model used by Meteo France (the French weather service). The visit at Mines-Paristech was done as part of Cédric's Ph. D. work at the Center for Research in Water Resources at the University of Texas at Austin; and the design, development and testing of RAPID were a large part of Cédric's Ph. D. dissertation which also included the adaptation of RAPID to run on the NHDPlus dataset that provides a "blue line" description of the river networks in the USA. Maintaining and enhancing RAPID were also a large part of Cédric's post-doctoral research at the Jackson School of Geosciences of the University of Texas at Austin and of his work at the University of California Center for Hydrologic Modeling. The current version of RAPID has been used with several land surface models and various river types of river networks.

RAPID is free, but who paid for it?
Cédric is the lead developer the RAPID code but would not have been able to lead the effort without the scientific and financial support of many including David R. Maidment, Florence Habets, Zong-Liang Yang and James S. Famiglietti. RAPID is made available through a Berkeley Software Distribution 3-clause license that is included in the source code and is therefore open-source. For more information on the funding and scientific support behind RAPID, please consult who paid for RAPID?.