Parameter Upstream Middle stream 0840 1500 2000 0740 1020 1806 Mean depth, m 0.55 0.90 0.96 1.22 0.89 2.17 Mean velocity, m/s 0.07 0.50 1.00 0.22 0.37 0.88 Flow, [m.sup.3]/s 1.90 26.23 53.50 15.25 18.56 86.14 Parameter Downstream 0940 1222 1530 Mean depth, m 0.79 0.96 0.72 Mean velocity, m/s 0.68 0.80 0.60 Flow, [m.sup.3]/s 17.29 25.30 13.74 Table 2: Means and standard deviations of the physicochemical characteristics of the downstream river of Batang Ai.

After the end of the generation an evaluation of the issued replacement cycle takes place based on statistical values as for example the mean velocity, RPA etc.

where [U.sub.i] and T are denote the mean velocity and temperature; [u'.sub.i], [u'.sub.j] and T' are the corresponding fluctuation components; [FORMULA NOT REPRODUCIBLE IN ASCII] and [FORMULA NOT REPRODUCIBLE IN ASCII] are the average Reynolds stresses and turbulent heat fluxes which need to be modelled to close the equations [16], [17] and [18].

where [P.sub.r] and [P.sub.cl] are the precipitation signal and clutter power, [[sigma].sub.r] and [[sigma].sub.cl] are the precipitation and clutter spectrum width, respectively, [[sigma].sup.2.sub.N] is the noise power, [bar.v] is mean velocity, and [T.sub.s] is sample time.

where u, v, and w denote the mean velocity in the streamwise (x), lateral (y), and vertical (z) directions, respectively, g is the gravitational acceleration, S is the energy slope, and -u'w' are the Reynolds stress tensor components.