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<br />2.6 <br /> <br />L (aH) aAx <br />ax Kx ay = at <br /> <br />(2.9) <br /> <br />where <br /> <br />1/2 <br />K = 1.486 A R2/3/ laHI <br />x n x ax <br /> <br />(2.10) <br /> <br />and Kx is the hydraulic conductivity, <br /> <br />The iteration then proceeds as follows until a pre'established tolerance <br />criteria for the change in depth is met. <br /> <br />4. The hydraulic conductivity is recalcul,ated. <br /> <br />5. New flow depths at the nodes are cal cul ated for time (t + At) using <br />Equat i on 2.9, and a 1 i near approximation for a nE!W depth, The net change <br />in the volume of water at each node is simply the summation of the <br />di scharge fl ux across the gri d boundari es in the four di rect ions. The <br />resultant change in depth for the time step i and grid element of area <br />Ax is <br /> <br />.fr <br /> <br />i <br />AHi , AQc At <br />c Ax <br /> <br />(2.11) <br /> <br />6, Re,evaluate Kx until mid,time,step depth estimates H~+1 are matched. <br /> <br />The computer model permits adjustment of the time increment to optimize the <br />variation of storage volume. <br /> <br />2.4 Hvoerconcentrated Sediment Flow Theorv <br />The model can simulate mud flood and mud flows with variation in the <br />sediment concentration by volume either spatia,lly or temporally in the watershed <br />channel. The mud flow event will be more real istic if the upstream watershed <br />channel flows are routed, thus creating a mud flow hydrograph for the alluvial <br />fan. Such a hydrograph would characteristically have a steep rise to the peak <br />and a truncated recessiDnal limb, The resulting outflow discharge for the <br />watershed and the corresponding temporal variation in sediment concentration <br />constitute the inflow hydrograph for routing the flow event over the alluvial <br />fan, <br /> <br />The highly variable nature of the fluid properties of mud flows make <br />accurate prediction of flow properties a difficult task. Mud flows are <br />