New dimension of nnode (number of nodes in the daily routing) needs to be added. Add MAXNODE in /modules/setdims/setdims.f and /modules/include/fmodules.inc).
The index of the downstream node. Each node has a node to which it passes water.
Node index for HRU surface runoff. Each HRU has a node to which surface runoff will go.
Node index for subsurface reservoirs. Each subsurface reservoir has a node to which subsurface flow will go.
Node index for ground-water reservoirs. Each ground-water reservoir has a node to which ground water will go.
Index of the final node in the system. Every routing network has a final node that represents the mouth of the modeled basin.
Storage coefficient, in hours. Approximate travel time of a flood wave to the next node.
Routing weighting factor, from 0 to 0.5. It expresses the amount of attenuation of the flood wave.
Calculated flow at selected nodes, in cubic feet per second.
Calculated outflow at selected nodes, in cubic feet per second.
This module routes flows between user-defined nodes in a stream network using the Muskingum routing equation (Linsley and others, 1982, p. 275). This module is based on the fixroute module created by the U.S. Bureau of Reclamation (T. Ryan, U.S. Bureau of Reclamation, written communication, May 1998) that used a fixed routing time between nodes. The route_time parameter in the fixroute module was replaced with two new parameters, K_coef and x_coef, of the Muskingum routing equation.
The Muskingum routing equation assumes a linear relation of storage to the inflow and outflow characteristics. The Muskingum method is based on the equation
where S is storage, in units of volume for a specific reach, K is the storage coefficient (K_coef), in units of hours, x is a coefficient between 0 and 0.5 (x_coef) (Linsley and others, 1982) , I is inflow, and O is outflow, both in units of discharge.
Storage-routing equations are often based on the assumption that the average flow during a routing period, t, is equal to the average flow at the start and end times, t 1 and t 2 , of the routing period. The continuity equation can be expressed as
[((I 1 + I 2 ) / 2) * t] - [((O 1 + O 2 )/ 2) * t] = S 2 - S 1 .
Outflow on day 2, O 2 , can be solved by substituting equation 1 for S in equation 2; and knowing the inflow at day 1, I 1 ; the inflow at day 2, I 2 ; and the outflow at day 1, O 1 . The storage equation, equation 2, can be written as
c 2 = (K - Kx - 12) / (K - Kx + 12),
assuming a time step of one day; K is in units of hours. In the musroute module, c 0 , c 1 , and c 2 are solved in the initialization function within MMS.
The three c constants are constrained to add numerical stability to the equation. If c 2 is less than or equal to zero because of a short travel time within a reach (less than daily), then c 1 = c 1 + c 2 and c 2 = 0.0. If c 0 is less than or equal to 0.0 because of a long travel time within a reach (more than daily), then c 1 = c 1 + c 0 and c 0 = 0.0
Linsley, R.K., Kohler, M.A., and Paulhus, J.L., 1982, Hydrology for engineers: New York, McGraw-Hill, p. 508.
URL for this page is http://pubsdata.usgs.gov/pubs/of/2002/ofr02362/htdocs/musroute/musroute_prms.htm
Page contact: Mark Mastin (mcmastin@usgs.gov),
253-428-3600, ext. 2609
Last modified: Friday, 11-Jan-2013 03:19:48 EST
