Quoted from: https://water.usgs.gov/cgi-bin/man_wrdapp?dr3m 

DR3M is a watershed model for routing storm runoff through a Branched system of pipes and (or) natural channels using rainfall as input.  DR3M provides detailed simulation of storm-runoff periods selected by the user.  There is daily soil-moisture accounting between storms.  A drainage basin is represented as a set of overland-flow, channel, and reservoir segments, which jointly describe the drainage features of the basin.  This model is usually used to simulate small urban basins.  Interflow and base flow are not simulated.  Snow accumulation and snowmelt are not simulated.

METHOD

       The rainfall-excess components include soil-moisture accounting, pervious-area rainfall excess, impervious-area rainfall excess, and parameter optimization.  The Green-Ampt equation is used in the calculations of infiltration and pervious area rainfall excess. A Rosenbrock optimization procedure may be used to aid in calibrating several of the infiltration and soil-moisture accounting parameters. Kinematic wave theory is used for both overland-flow and channel routing.  There are three solution techniques available:  method of characteristics, implicit finite difference method, and explicit finite difference method.  Two soil types may be defined.  Overland flow may be defined as turbulent or laminar.  Detention reservoirs may be simulated as linear storage or using a modified-Puls method. Channel segments may be defined as gutter, pipe, triangular cross section, or by explicitly specifying the kinematic channel parameters alpha and m.

HISTORY

       1991 - DR3M-version II, added option to output simulated time-series data to Watershed Data Management (WDM) file.  Output file modified to reduce width from 132 characters to 80 characters or less.

       1984 - DR3M-version II, WDM file replaces "card" input of time-series data.

       1982 - DR3M-version II, added two solution techniques for kinematic wave routing.  Improved general output.

       1978 - Original DR3M version, incorporated the routing component from a version of the Massachusetts Institute of Technology catchment model into the lumped parameter rainfall-runoff model.

       1972 - A lumped parameter rainfall-runoff model for small rural watersheds

DATA REQUIREMENTS

       Daily precipitation, daily evapotranspiration, and short-interval precipitation are required.  Short-interval discharge is required for the optimization option and to calibrate the model.  These time series are read from a WDM file.  Roughness and hydraulics parameters and sub-catchment areas are required to define the basin. Six parameters are required to calculate infiltration and soil-moisture accounting.  Up to three rainfall stations may be used. Two soil types may be defined.  A total of 99 flow planes, channels, pipes, reservoirs, and junctions may be used to define the basin.

OUTPUT OPTIONS

       The computed outflow from any flow plane, pipe, or channel segment for each storm period may be written to the output file or to the WDM file.  A summary of the measured and simulated rainfall, runoff, and peak flows is written to the output file.  A flat file containing the storm rainfall, measured flow (if available), and simulated flow at user selected sites can be generated.  A flat file for each storm containing the total rainfall, the measured peak flow (if available), and the simulated peak flow for user-selected sites can be generated.

SYSTEM REQUIREMENTS

       DR3M is written in Fortran 77 with the following extension: use of include files. The UTIL, ADWDM, and WDM libraries from LIB are used. A subset of these libraries is provided with the code and may be used instead of the libraries, this subset uses INTEGER*4 and mixed type equivalence. For more information, see System Requirements in LIB.

DOCUMENTATION

       Alley, W.M., and Smith, P.E., 1982, Distributed routing rainfall-runoff model--version II:  U.S. Geological Survey Open-File Report 82-344, 201 p.

RELATED DOCUMENTATION

       Flynn, K.M., Hummel, P.R., Lumb, A.M., Kittle, J.L., Jr., 1995, User's manual for ANNIE, version 2, a computer program for interactive hydrologic data management:  U.S. Geological Survey Water-Resources Investigations 95-4085, 211 p.

REFERENCES

       Dawdy, D.R., Lichty, R.W., and Bergmann, J.M., 1972, A rainfall-runoff simulation model for estimation of flood peaks for small drainage basins: U.S. Geological Survey Professional Paper 506-B, 28 p.

       Dawdy, D.R., Schaake, J.C., Jr., and Alley, W.M., 1978, User's guide for distributed routing rainfall-runoff model:  U.S. Geological Survey Water-Resources Investigations Report 78-90, 146 p.

       Doyle, H.W., Jr., and Miller, J.E., 1980, Calibration of a distributed routing rainfall-runoff model at four urban sites near Miami, Florida: U.S. Geological Survey Water-Resources Investigations Report 80-1, 87 p.

       Guay, J.R., and Smith, P.E., 1988, Simulation of quantity and quality of storm runoff for urban catchments in Fresno, California:  U.S. Geological Survey Water-Resources Investigations Report 88-4125, 76 p.

       Leclerc, Guy, and Schaake, J.C., Jr., 1973, Methodology for assessing the potential impact of urban development on urban runoff and the relative efficiency of runoff control alternatives:  Ralph M. Parsons Laboratory Report no. 167, Massachusetts Institute of Technology, 257 p.