Hydrologic features and processes of the Vermilion River

Abstract: The hydrology of the Vermilion River is affected by the climate, the
geographic features of the basin, the diversion of water from other basins
into the river, the physical characteristics and configuration of drainage
channels, and the actions of tides and winds. The river is a coastal stream
that flows through the relict deltaic deposits of the Atchafalaya and Red
Rivers. Water from the Vermilion River is used primarily for rice irrigation
and for the dilution of municipal and industrial effluents.

Prior to flow augmentation from the Atchafalaya River, low discharges
were frequent in the Vermilion River. Operation of a pumping plant has
increased discharge during low flow and decreased discharge during high flow.
Although the Vermilion River is a highly regulated stream, it still exhibits
variable flow.

Variable discharges in the Vermilion River are caused, in part, by the
effects of tides and winds. Nearly every reach of the river is affected by
tides. Diurnal, semidiurnal, and mixed tides occur, but the diurnal tide is
the most dominant pattern. Tidal range in the downstream reaches generally
is between 1 and 2 feet. Sustained northerly winds can significantly lower
river elevation, and sustained southerly winds can significantly raise river
elevation, in the downstream reaches.

Incoming tides in the downstream reaches tend to stagnate flow and
reduce reaeration coefficients. Reaeration coefficients, calculated for
measurements made August 6, 1985, ranged from 0.038 per day in the downstream
reaches to 0.723 per day in the upstream reaches. Reaeration potential is
reduced in the downstream reaches by incoming tides. Computation of
reaeration coefficients for average conditions is difficult because stream
velocities are extremely variable. Additional studies are needed to
determine velocities, flow patterns, average reaeration coefficients, and
frequency and duration of high and low discharges to more completely define
the hydrology of the Vermilion River.


Citation: Baker, N. T. (1988). Hydrologic features and processes of the Vermilion River, Louisiana. Baton Rouge, La., Dept. of the Interior, U.S. Geological Survey, Water-resources investigations report 88-4019.

URL: https://pubs.er.usgs.gov/publication/wri884019