channel geometry. For further details see for example Price (1985)
and Raudkivi (1979).- The hydrologic method (kinematic solution)is the simplest and most
frequently used method, particularly after the connection between its
parametersKandx– described below – (Muskingum method) and
the channel physical characteristics had been established by Cunge
(Muskingum–Cunge method) thus in effect bridging the gap between
the last two methods. Again its application requires at least the data
from one previous flood (e.g. Shaw, 1994).
The Muskingum method is basically an extension of the reservoir routing
methods taking into account that the storage (V) in a channel is a function of
both the inflow (I) and the outflow (O), i.e. that in addition to the prism
storage there is a (positive or negative) wedge storage (equation (8.13)). Thus
VK[Ox(I O)] (8.39)whereKis a storage constant (units of time) and xa weighting factor. It is
evident that in the case of a reservoir x0 (equation (4.7)). Combining
equation (8.39) with continuity (I OdV/dt; equation (4.2) or (4.3)) and
eliminating the storage terms leads to the routing equation (∆tis the
routing period):
O 2 c 0 I 2 c 1 I 1 c 2 O 1 (8.40)RIVER FLOOD ROUTING 341
Fig. 8.7 Parshall flume