Figure 4.4.2 Routing of undesirable inflows
suspended solids, nutrients or other constituents, and corresponding concentrations in the reservoir.
Using the data collected, as well as a knowledge of the flow patterns through the reservoir, the
location and elevation of the inflow in the pool must be predicted. Akiyama and Stefan (1985) derive
the equations necessary to predict the routing of turbidity currents (a form of density current) through a
reservoir. It may be possible to incorporate these equations into a numerical model to help the
reservoir manager make accurate, real-time predictions of the flow events. However, mixing of the
inflow with reservoir water, as well as dispersion in the reservoir, may be difficult to predict, even with a
Using the predicted location of the undesirable inflow in the reservoir, the water control plan
should be evaluated to determine appropriate operations to minimize impacts to the reservoir. This may
involve varying the release flow rate or changing the selective withdrawal port elevation to withdraw the
inflowing water from a specific elevation more efficiently. Since retention of the undesirable inflow in
the pool is likely detrimental to the water quality of the reservoir, release of these flows should be
Although application of this technique may be standard procedure for most water quality
managers, published accounts of inflow routing are limited.
Nix (1981) reported that the adjective transport of organic matter resulting from an inflow event
contributed to the oxygen demand of a reservoir metalimnion during the stratified periods. He indicated
that residence time of this organic matter could be minimized by increasing the discharge rate of the
project through the stratification season.