1. Early Warning Flood Detection
CSE 646 – Assignment 1
Arun Ramachandramurthy

2. What is this System?
An Environmental application of Wireless Sensor Network(WSN).
Provides statistical model based solution to the early prediction of floods in rivers
This system consists of only a small number of nodes to cover river basins of sq.km using a heterogeneous communication structure.

3. How is it different from current systems?
Current prediction systems operate on a prediction model which requires more computational power and time than available on a sensor network.
Example of operational model - Calculating the increase in water level by estimating the rainfall water runoff from the surface.
Model proposed in the paper is based on statistical methods and is feasible within the power available in the sensor network and consumes much less time.

4. What are the design parameters?
This predictive environmental WSN poses number of design challenges:
The WSN nodes should withstand the events such as flood, hurricanes.
Survive the node failures, prolonged use.
Limited power.
Should operate even in disaster-free periods.
Measure variety of variables contributing to the disaster

5. Design parameters continued..
Requires heterogeneous sensor support
Communication over the large geographical area.
Design of the prediction model which is different from the current operational models.

6. System Requirements
Monitor events over large geographic area of approximately sq.km
Provide real time communication of measurements of air temperature, amount of rainfall and past flow
Survive long years of element exposure with minimal maintenance
Recover from node losses

7. System Requirements continued..
Minimize costs
The distributed model driven by data collected.
Distribute among nodes the significant computation needed for the prediction.

8. WSN Architecture & Components
Two tiered architecture of sensor nodes
First tier consists of sensor nodes which operate at 900 MHz covering a dense area and have short communication range ~8km.
Outer tier consists of nodes which have long range communication range of ~25km. They operate at 144 MHz
The system also consists of office and community nodes.
The sensor types used for collecting data are : Rainfall sensor, pressure sensor, temperature sensor.
Of course the radio component in all the sensor nodes.

9. Simple depiction of the Architecture
System Architecture
Community
Office
River
Short range communication area
Short range communication area
Short range communication area
Long range comm.

10. How does it approach the challenges?
Prediction model – A distributed statistical model of linear regression.
Network of heterogeneous sensor nodes – as mentioned previously two sets of senor nodes one which operate in short communication range and the other in long communication range.

11. Conclusion
This application was deployed and tested on certain Charles river at Dover.
This system is node limited due to region size and cost constraints.
It also has significant system requirements due to real-time need for the data, destructive events.
References :
Paper presented in Sensys Model Based Monitoring of Early warning Flood Detection by Elizabeth A. Basha,Sai Ravela,Daniela Rus all from MIT.