13 Water Quality
297
13.4.3 Temperature
From a water quality standpoint, thennal enrichment is defined as increasing the
temperature of a water body by anthropogenic activity. Thennal pollution exists when
biological activity in the water body is affected. The most common source of thenna!
pollution is cooling water releases from electrical power plants. Remotely sensed data
have been used to map thennal discharge into streams, lakes and coastal waters from
electrical power plants (Stefan and Schiebe 1970; Gibbons et al. 1989). Mapping
thenna! plumes in river and coastal waters has provided accurate estimates of absolute
temperature and provided spatial and temporal patterns ofthennal releases (see Fig.
13.6). Mapping thennal enrichment in streams, lakes, reservoirs, and coastal waters
has been useful in managing thermal releases from electrical power plants. Management of power plant releases can be designed to reduce the impact of thennal releases
based on thermal patterns determined for different flow regimes from remotely sensed
data. Improved quantitative estimates of surface water temperatures also provide input
for interpreting outputs from mathematical models of thennal plumes. Aircraft
mounted, thennal sensors are especially useful in studies of thennal plumes because
of the ability to control the timing of data collection that is critical for studying
thennal releases.
Other anthropogenic activity can also lead to decreases in surface water temperature. Promotion of tree growth in riparian zones along streams can intercept solar
energy preventing it from being absorbed by surface waters. One effect of suspended
sediments in water is to backscatter significant quantities of solar energy that would
otherwise be absorbed in a clear lake. This process, in effect, rejects solar energy and
Fig. 13.6. Surface temperatures of Lake Baikai derived from A VHRR band 4 data for September 4,
1991 (Bolgrien et al. 1995; Reproduced with permission of AmericaI Society of Photogrammetry and
Remote Sensing, Bethesda, MD)
297
13.4.3 Temperature
From a water quality standpoint, thennal enrichment is defined as increasing the
temperature of a water body by anthropogenic activity. Thennal pollution exists when
biological activity in the water body is affected. The most common source of thenna!
pollution is cooling water releases from electrical power plants. Remotely sensed data
have been used to map thennal discharge into streams, lakes and coastal waters from
electrical power plants (Stefan and Schiebe 1970; Gibbons et al. 1989). Mapping
thenna! plumes in river and coastal waters has provided accurate estimates of absolute
temperature and provided spatial and temporal patterns ofthennal releases (see Fig.
13.6). Mapping thennal enrichment in streams, lakes, reservoirs, and coastal waters
has been useful in managing thermal releases from electrical power plants. Management of power plant releases can be designed to reduce the impact of thennal releases
based on thermal patterns determined for different flow regimes from remotely sensed
data. Improved quantitative estimates of surface water temperatures also provide input
for interpreting outputs from mathematical models of thennal plumes. Aircraft
mounted, thennal sensors are especially useful in studies of thennal plumes because
of the ability to control the timing of data collection that is critical for studying
thennal releases.
Other anthropogenic activity can also lead to decreases in surface water temperature. Promotion of tree growth in riparian zones along streams can intercept solar
energy preventing it from being absorbed by surface waters. One effect of suspended
sediments in water is to backscatter significant quantities of solar energy that would
otherwise be absorbed in a clear lake. This process, in effect, rejects solar energy and
Fig. 13.6. Surface temperatures of Lake Baikai derived from A VHRR band 4 data for September 4,
1991 (Bolgrien et al. 1995; Reproduced with permission of AmericaI Society of Photogrammetry and
Remote Sensing, Bethesda, MD)