Environmental Engineering Reference
In-Depth Information
Table 3.4
Threats, description and conservation
Threats
Description
Conservation
1. Shoreline
changes
A sand spit has formed near Kakinada Bay
over a period of 100 years (Fig.
3.11
). During
1848
Dredging of the bay entrance may reduce the
magnitude of tidal currents (preferably in
terms of amplitude) due to which restoration
of ecological condition will occur and the
hypersaline condition may be managed
uence of Godavari
River shifted its course from Coringa Bay to
about 5 miles South East. In addition to this,
the construction of dam at Dowleswaram
(1846
-
1852) and deforestation in Godavari
Basin greatly reduced the flushing capacity of
the river and accelerated the sediment
transport. These phenomena resulted in
silting up of the Coringa creeks. This silting
caused the opening of the major branch of
Godavari River in open sea in Hope Island
and the increased sediment input resulted in a
formation of a shoal during 1851. Littoral
currents (
1852, major con
fl
-
owing towards northern direction)
tend to deposit the littoral drift materials,
while tidal currents (perpendicular to shore)
tend to remove these materials. Since tidal
currents became weak (because of the large
littoral bay mouth), littoral currents
dominated the deposition and the shoal
developed into a sand spit. With the
increased growth rate of the sand spit
northward, the bay entrance (between sand
spit and mainland) reduced causing strong
tidal currents which is the main cause of
development of a hypersaline environment
fl
People
'
s participation through the model of
joint mangrove management (JMM) will help
to increase the awareness of the local
villagers regarding the importance of
mangroves. Also, plantation programme
should be taken through proper institutional
framework (preferably Forest Department)
involving the local people
2. Mangrove
felling
Felling of mangroves for collecting timber,
fuel wood, etc., results in the loss of
mangroves. As many as 16 adjacent villages
depend on mangroves as a source for
rewood, some of the mangrove areas close
to these villages exhibit denuded mangrove
vegetation
3. Hypersaline
condition
In some pockets, natural degradation of
mangrove occurs due to hypersaline
condition because of reduced tidal flushing
Rainwater harvesting and channelization of
the harvested rainwater through
sh bone
model may help diffuse the freshwater in the
mangrove ecosystem by increasing the
dilution factor of the system
4. Conversion of
mangrove area to
aquaculture
In Coringa mangrove ecosystem, the area
under aquaculture has increased from 669 ha
to 4,669 ha during a span of 10 years
(1988
The best way to preserve the mangrove
ecosystem in its pristine form is to reduce the
anthropogenic pressure arising out of
livelihood. Shrimp culture, being a lucrative
livelihood in mangrove ecosystem, can only
be diverted if some alternative livelihood is
provided to the shrimp culturists in order to
meet the
nancial need. These alternative
livelihoods may encompass several non-
conventional approaches such as oyster
culture, seaweed culture, crab fattening and
mangrove
1998) which is an increase of
597.90 %. The overlay analysis reveals that
about 639 ha of mangrove area has been
converted into aquaculture
-
fl
oral based
sh feed preparation
(continued)
