Articles | Volume 8, issue 3
https://doi.org/10.5194/gmd-8-865-2015
https://doi.org/10.5194/gmd-8-865-2015
Model description paper
 | 
30 Mar 2015
Model description paper |  | 30 Mar 2015

RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model (v1.15)

A. J. Long

Abstract. The Rainfall-Response Aquifer and Watershed Flow Model (RRAWFLOW) is a lumped-parameter model that simulates streamflow, spring flow, groundwater level, or solute transport for a measurement point in response to a system input of precipitation, recharge, or solute injection. I introduce the first version of RRAWFLOW available for download and public use and describe additional options. The open-source code is written in the R language and is available at http://sd.water.usgs.gov/projects/RRAWFLOW/RRAWFLOW.html along with an example model of streamflow. RRAWFLOW includes a time-series process to estimate recharge from precipitation and simulates the response to recharge by convolution, i.e., the unit-hydrograph approach. Gamma functions are used for estimation of parametric impulse-response functions (IRFs); a combination of two gamma functions results in a double-peaked IRF. A spline fit to a set of control points is introduced as a new method for estimation of nonparametric IRFs. Several options are included to simulate time-variant systems. For many applications, lumped models simulate the system response with equal accuracy to that of distributed models, but moreover, the ease of model construction and calibration of lumped models makes them a good choice for many applications (e.g., estimating missing periods in a hydrologic record). RRAWFLOW provides professional hydrologists and students with an accessible and versatile tool for lumped-parameter modeling.

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Short summary
RRAWFLOW is a lumped-parameter model that simulates streamflow, springflow, groundwater level, or solute transport (available for download). For many applications, lumped models simulate the system response with equal accuracy to that of more complex distributed models. Gamma functions are used for estimation of impulse-response functions, and a spline fit to a set of points is introduced as an optional method for this purpose. Several options are included to simulate time-variant systems.