IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
  
  
acting as obstruction to the sediment movement. This had 
resulted in erosion on the southern coast and deposition on the 
northern coast. The IRS P4 OCM data are extremely useful to 
study sediment dispersal and sediment transport studies due to 
their 2-day repeat cycle. OCM data has been used for 
computing advective velocity of surface currents (Prasad et al. 
2002). 
5. MARINE WATER QUALITY 
Anthropogenic activities such as discharge of industrial and 
municipal sewage, land use, tourism, maritime transport, 
offshore oil exploration and production, dumping at sea 
degrade the marine. environment. Turbidity and colour are 
indicators of water quality. Chlorophyll indicates trophic status, 
nutrient load and possibility of pollutants in coastal waters. 
Suspended sediments affect navigation, fisheries, and aquatic 
life, recreation potential of sea resorts. As the suspended 
sediments carry absorbed chemicals and fronts are associated 
with pollutants, the knowledge about their movement will help 
in predicting waste effluent transportation path. Suspended 
sediments are easily observed on the satellite imagery. Tides 
play an important role in the movement of suspended sediments 
and fronts (Nayak and Sahai, 1985). Successive images from 
IRS P4 OCM have been used for understanding impact of tides 
on sediments in tide- and wave-dominated regions. A distinct 
front was observed separating the Gulf waters and the Arabian 
Sea under different tidal conditions. This suggests that there is 
very little mixing between these two waters. Hence the 
poliutants discharged in the Gulf will circulate within the Gulf 
and ultimately will settle in the Gulf itself. 
Municipal sewage and industrial waste are major types of 
pollution observed on the coast. Toxic chemicals, nutrients, 
sediments and solid waste discharged in to coastal waters affect 
coastal ecosystems. Such waste out-falls are difficult to detect 
as near shore waters are turbid. Some of the effluents have 
colour and can be detected. One such waste out-fall from 
titanium factory near Thiruvananthapuram and sugar mill 
discharge near the Kakinada Coast, West and east coast of India 
were traced using high- resolution satellite data. Indian coastal 
waters are relatively free from pollution except few pockets 
around industrialised zones and large cities. 
Oil spills from vessels and platforms are infrequent. In 
such cases, oil rises to surface and spread across the 
water body and thus amenable to remote detection. In 
one such study, IRS P4 OCM data was used for 
monitoring oil slick occurred in the Gulf of Kachchh. 
However, 2-day repeat cycle of OCM data is not 
adequate for monitoring slick in tide-dominated areas. 
Satellite surveillance is possible if high-resolution remote- 
sensing geo-synchronous satellite is available. Smaller spills 
from vessels, maintenance of oil infrastructure is a major source 
and is not detected on satellite images. Systematic observation 
with high-resolution satellite data will be helpful to study their 
effect on coastal habitats. 
Incidences of harmful algal blooms have increased worldwide. 
They may occur with cyclic regularity in certain regions where 
certain optimum environmental conditions prevail in marine 
waters. These planktons produce certain toxins, which 
adversely affect fish and other organisms. The bloom usually 
takes place rather suddenly and may spread with amazing 
speed, changing colour of surface water into red, green or hay 
colour. CZCS-derived chlorophyll map was used to study such 
374 
bloom in the Baltic Sea. IRS P4 OCM data have been used to 
monitor Trichodesium bloom in the Arabian, Sea using OCM 
data. 
6. MARINE ENVIRONMENT AND CLIMATE CHANGE 
The marine environment is sensitive and vulnerable to climate 
change. It is necessary to determine present status of the 
various systems and to predict future conditions. The high 
degree of uncertainty in present information inhibits effective 
management and limits the ability to make predictions and 
assess environmental change. Systematic collection of data on 
marine environment needed to apply integrated management 
approaches and predict effect of global climate change. Global 
climate change may compound pressures on coastal ecosystems 
through warmer sea surface temperature, altered ocean 
circulation patterns, changing storm frequency and rising sea 
levels. 
It was observed on IRS P4 images that productivity of the 
coastal waters of the Orissa coast increased after the Orissa 
cyclone Nayak et al. 2001). The frequency of cyclone has also 
increased during last several years. It may be interesting to see 
long-term impact on productivity in view of global warming. 
Coral bleaching can occur due to increase in temperatures 1?-2? 
C higher than average in the warm season. Coral bleaching 
provides a direct indicator of the condition of coral reefs. In last 
two decades, incidence of mass bleaching has been increasingly 
observed (Goreau and Hayes, 1994, Goreau, et al. 1997). 
NOAA SST data have been extensively used to study the 
relationship between increase in SST and coral bleaching 
(NOAA, 1998, ICRS, 1998). It is possible to predict coral : 
bleaching by monitoring SST (Strong, 1998). The wide spread 
coral bleaching observed during 1997-98 is an example of the 
effect of elevated SST. This event of bleaching on the 
Lakshadweep Islands, India was also recorded using IRS LISS 
III data. 
The sea level rise is highly variable both in terms of time and 
space. Various estimates for the Indian coast vary from 0.5 to 
2.2 mm per year. It is expected that the rise in sea level will 
lead to increased erosion and habitat loss, increased salinity in 
estuaries, alter tidal range, change sediment transport and 
increase coastal flooding. Rising levels will also increase 
impact of storm surges. The response of different ecosystems to 
sea level rise has been evaluated based on their characteristics 
for the Gujarat coast (Nayak, 1994). Small increase in sea level 
has potential of causing significant changes to small islands and 
low-lying coasts. It seems that conservation of mangrove areas 
will be one of the Important steps to mitigate impact of the sea 
level rise (Baba and Nayak, 2002). 
7. COASTAL ZONE MANAGEMENT 
The management of coastal zone requires data on varied 
aspects as discussed earlier. Information exists in form of 
thematic maps as well as non-spatial format. Thus it is difficult 
to integrate these data conventionally. It is, therefore necessary 
to develop a computer-based information system composed of 
comprehensive and integrated set of data designed for 
decision-making. In this remote-sensing-based management 
plan, basic input about coastal areas is derived from remote 
sensing data. Integration of this thematic data with other 
secondary data would lead to identification of suitable sites and 
initial zoning. 
WR dud Um wA 
°° 0 ho md 
Ff Ton bed 
pm