Mj. Sabo et al., Hydrology and aquatic habitat characteristics of a riverine swamp: I. Influence of flow on water temperature and chemistry, REGUL RIVER, 15(6), 1999, pp. 505-523
We monitored water temperature, air temperature, hydrologic characteristics
, and chemical variables for 25 months in a 254-km(2) portion of the Atchaf
alaya Basin, Louisiana, USA, a distributary swamp of the Mississippi River.
We related observed trends in thermal and chemical variables to characteri
stics of the flood pulse, available channel types, and paths of water flow
within the study area. Dissolved oxygen (range 0.05-13.05 mg L-1), percent
oxygen saturation (range 0.6-142.4%), and pH (range 6.31-8.52) increased as
river stages decreased, and water temperatures (range 4.75-32.25 degrees C
), specific conductance (range 207.8-931.5 mu mhos), and the top-bottom dif
ference in dissolved oxygen (- 7.5-12.05 mg L-1) increased as air temperatu
res rose. The maximum variance observed for all chemical and thermal habita
t characteristics occurred during periods when air temperatures exceeded, a
nd river stages were less than, their respective medians observed during th
e study. At any point in time, thermal and chemical variables varied most a
mong stations in water courses with no visible water turbulence low-energy
channels), and these channels consistently had lower dissolved oxygen, perc
ent oxygen saturation, and pH than turbulent water courses (high-energy cha
nnels) or lakes contained. Water was directed from the river into one regio
n of the study area from two opposing directions, thereby impeding water fl
ow through the region. Low-energy channels in this region consistently exhi
bited lower dissolved oxygen concentrations, percent oxygen saturation, and
pH than was observed in low-energy channels of regions where water flow wa
s unimpeded. The quantity and quality of aquatic habitat characteristics in
riverine swamps can be manipulated by controlling the timing and magnitude
of the flood pulse, relative availability of different water courses, and
internal paths of water flow through the swamp. Copyright (C) 1999 John Wil
ey & Sons, Ltd.