2.1. Fire and Flood Detection
Large number of environmental applications makes use of WSNs. Sensor networks are
deployed in forest to detect the origin of forest fires. Weather sensors are used in flood detection
system to detect, predict and hence prevent floods. Sensor nodes are deployed in the
environment for monitoring biodiversity.
The Forest-Fires Surveillance System (FFSS) [10] was developed to prevent forest fires in the
South Korean Mountains and to have an early fire-alarm in real time. The system senses
environment state such as temperature, humidity, smoke and determines forest-fires risk-level
by formula. Early detection of heat is possible and this allows for the provision of an early alarm
in real time when the forest-fire occurs, alerting people to extinguish forest-fires before it grows.
Therefore, it saves the economical loss and environment damage. Similarly, a typical
application of WSN for flood detection and prevention is the ALERT system [11] deployed in
the US. Rainfalls, water level and weather sensors are used in this system to detect, predict and
hence prevent floods. These sensors supply information to a centralized database system in a
pre-defined way.
2.2. Biocomplexity Mapping and Precision Agriculture
Wireless sensor networks can be used to control the environment which involves monitoring air,
soil and water. Sensors are deployed throughout the field and these sensors form a network that
communicate with each other to finally reach some processing centre which analyse the data
sent and then accordingly adjust the environment conditions (e.g., if the soil is too dry, the
processing centre send signals which actuators recognise accordingly and thus can start the
sprinkling system. Biocomplexity mapping system helps to control the external environment.
Sensors are used to observe spatial complexity of dominant plant species [12]. An example is
the surveillance of the marine ground floor where an understanding of its erosion processes is
important for the construction of offshore wind farms [13].
Precision agriculture is an emerging WSN application area to monitor and control the amount of
pesticides present in drinking water, monitor the level of soil erosion and the level of air
pollution [14]. Precision agriculture encompasses different aspects such as monitoring soil, crop
and climate in a field. Huge amount of sensor data from large-scale agricultural fields are
frequently generated in such an application.
2.3. Habitat Monitoring
Concerns associated with the impacts of human presence in monitoring plants and animals in
field conditions have to a large extent been overcome by WSNs [15]. Sensors can now be
deployed prior to the onset of the breeding season and while plants are dormant or the ground is
frozen as well as on small islets where it is unsafe or unwise to repeatedly attempt field studies.
Such deployment represents a substantially more economical method for conducting studies
than traditional personnel-rich methods where substantial proportion of logistics and
infrastructure must be devoted to the maintenance of field studies, often at some discomfort and
occasionally at some real risk.