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13.5.2 Temperature Profile
Water temperature plays an important role in determining the amount of oxygen
found in the lake. Oxygen is more soluble in cold than warm water. Most lakes over
20 ft deep stratify during the summer into a warm, lighted upper layer (epilimnion)
and a cold, dark lower layer (hypolimnion). Thus, the cold lower layer can potentially hold more oxygen than the warmer upper layer. it is important to define the
thermal layers in a lake when characterizing dissolved oxygen conditions (USEPA
2002).
13.5.3 Salinity
Coastal seawater salinity affected by the discharge of the fresh or low saline water
from inland source such as the coastal lakes.
13.5.4 Monitoring Sedimentation
Sedimentation problems occur when erosion is taking place in the watershed.
Surface runoff washes sand and silt into the lake where it settles to the bottom and
creates shallow areas that interfere with lake use and enjoyment. In addition, sediments often carry significant amounts of nutrients that can fertilize rooted aquatic
plants and algae.
Concerning the suspended solids, some of the silt and organic matter that enters
a lake does not settle to the lake bottom. Instead, it remains suspended in the water.
These suspended solids decrease water transparency and can affect the suitability of
the lake habitat for some species. One can monitor the suspended sediment condition by measuring two parameters: water transparency using a Secchi disk; and total
suspended solids (USEPA 2002).
13.5.5 Monitoring Acidification
The measurement of pH is the detection of lake acidity and alkalinity status. The pH
is measured on a scale of 0–14. The lower the pH, the higher the concentration of
hydrogen ions and the more acidic the solution. Acid rain typically has a pH of
4.0–4.5. In contrast, most lakes have a natural pH of about 6.0–9.0. The pH of a lake
sample can be easily determined by using a portable, battery-powered pH meter.
13 Egyptian Nile Delta Coastal Lagoons: Alteration and Subsequent Restoration
13.5.2 Temperature Profile
Water temperature plays an important role in determining the amount of oxygen
found in the lake. Oxygen is more soluble in cold than warm water. Most lakes over
20 ft deep stratify during the summer into a warm, lighted upper layer (epilimnion)
and a cold, dark lower layer (hypolimnion). Thus, the cold lower layer can potentially hold more oxygen than the warmer upper layer. it is important to define the
thermal layers in a lake when characterizing dissolved oxygen conditions (USEPA
2002).
13.5.3 Salinity
Coastal seawater salinity affected by the discharge of the fresh or low saline water
from inland source such as the coastal lakes.
13.5.4 Monitoring Sedimentation
Sedimentation problems occur when erosion is taking place in the watershed.
Surface runoff washes sand and silt into the lake where it settles to the bottom and
creates shallow areas that interfere with lake use and enjoyment. In addition, sediments often carry significant amounts of nutrients that can fertilize rooted aquatic
plants and algae.
Concerning the suspended solids, some of the silt and organic matter that enters
a lake does not settle to the lake bottom. Instead, it remains suspended in the water.
These suspended solids decrease water transparency and can affect the suitability of
the lake habitat for some species. One can monitor the suspended sediment condition by measuring two parameters: water transparency using a Secchi disk; and total
suspended solids (USEPA 2002).
13.5.5 Monitoring Acidification
The measurement of pH is the detection of lake acidity and alkalinity status. The pH
is measured on a scale of 0–14. The lower the pH, the higher the concentration of
hydrogen ions and the more acidic the solution. Acid rain typically has a pH of
4.0–4.5. In contrast, most lakes have a natural pH of about 6.0–9.0. The pH of a lake
sample can be easily determined by using a portable, battery-powered pH meter.
13 Egyptian Nile Delta Coastal Lagoons: Alteration and Subsequent Restoration