8268

• UCREFRP Catalog Number: 8268
• Author: Vaill, J. E.
• Title: Traveltime and Dispersion of Contaminants in the Yampa River from Steamboat Springs to the Green River, Northwestern Colorado.
• USFW Year: 2000.
• USFW - Doc Type: USGS WRIR 99-4239,
• Copyright Material: NO

HOW TO ESTIMATE THE PEAK
CONCENTRATION

In order to compute the most probable peak
concentration at a point downstream from a spill, it is
necessary to determine (or estimate) the volume of the
spill. Please note the volume of the spill must be calcu-
lated or estimated in pounds.
Step 4.-Determine the unit-concentration (Cup)
from table 5 for the streamflow and sites of interest
determined in steps 1 and 2.
Step 5.-Compute the most probable peak
concentration by multiplying 0.016 times the unit-
concentration value (Cup) times the volume of spill (in

pounds) divided by streamflow (in cubic feet per
second) (Jobson, 1996).
Step 6.-Compute the time the trailing edge of
the spill will arrive at the downstream points of
interest.

HOW TO DETERMINE THE TRAVELTIME
OF THE TRAILING EDGE

The time (TdlO ) when the trailing edge of the
contaminant cloud (0.1 times the peak concentration)
reaches a particular point in the river can be obtained
by dividing 555.6 by the unit-concentration value
(Cup) obtained from table 5 (Jobson, 1996).