Groundwater Monitoring using Smart Sensors

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Groundwater Monitoring using Smart Sensors
MS Project presentation

• Srikanth Anumalla
• Advisor Dr. Byrav Ramamurthy

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Overview

• Groundwater Monitoring
• Current Methods
• Our Idea
• Prototype Implementation
• Challenges
• Related Work
• Demo

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Groundwater

• Groundwater
• Groundwater is water that is found underground in
  the cracks and spaces in soil, sand, and rocks.
• Principal source of drinking water for 50
  population in US

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Groundwater Monitoring

• Need
• Management of well fields
• Response to large scale pumping
• Response to precipitation
• Continuous sensitivity to climate changes
• Contamination
• Data
• Groundwater Level
• Groundwater quality

condensation
transpiration
precipitation
evaporation
pumping
infiltration
water table
discharge area
aquifer
groundwater flow
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Groundwater Level
underground surface below which the ground is
wholly saturated with water (Websters)
Measuring point
Land Surface
Groundwater Level (elevation)
Depth to water from LS
Water Level
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Groundwater Level Measurement

• Measurement
• Manual (Steel tape, Electric-
  -tape)
• Pressure transducer

Measuring point
Land Surface
Length of cable
Groundwater Level (elevation)
Water Level
Length measured by Pressure transducer
Pressure transducer
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Groundwater level data usage

• To determine annual changes of groundwater in
  storage
• To estimate recharge rates
• To determine direction and gradient of
  groundwater flow
• To develop groundwater models and forecast trends
• To design, implement, and monitor the
  effectiveness of groundwater management and
  protection programs

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Data Collection in Nebraska Natural Resource
Districts (NRD)

• Using pressure transducer
• Manual collection of data
• Usually two times a year, often once a year
• Disadvantages
• Delay in data availability
• Cost (people, travel, and other logistics)

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Real-time groundwater monitoring

• Water managers need more timely and accurate data
  to assess ground water conditions to manage
  adverse situations such as drought and loss of
  pumpage in residential water supply
• Commercial off-the-shelf solution exists (e.g.
  Solinst STS)
• Large scale deployment is prohibitively costly

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Our idea

• To develop a low-cost and flexible real-time
  groundwater level monitoring system leveraging
  the latest advancements in sensor and network
  technologies
• Using
• Low cost Field Programmable Gate Arrays (FPGA)
• IEEE 802.11b Wireless LAN

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Overview of the system
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Components of the system

• Data Acquisition Unit (DAU)
• FPGA and Analog-Digital converters
• Data Transfer Unit (DTU)
• IEEE 802.11b WLAN
• Data Processing Unit (DPU)
• Custom software

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Data Acquisition Unit (DAU)

• Consists of
• Pressure sensor
• Analog-Digital converter
• IEEE 802.11b enabled FPGA
• Solar Panel for power
• Functionality
• Data acquisition
• Temporary data storage
• Response to data requests

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Data Transfer Unit (DTU)

• Connectivity between base station and nodes using
  IEEE 802.11b Wireless LAN
• Light weight routing protocols to solve line of
  sight problem
• High gain directional antennas for long range
  wireless connectivity

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Data Processing Unit (DPU)

• Implemented in a software module
• Support for different types of data presentation
  (Graphs, tables)
• New analysis techniques

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Project Objective

• To develop a prototype implementation for Data
  Acquisition Unit (DAU)
• Responsible for collecting the water level data
  from a water column, storing the data locally and
  responding to the requests from a remote
  location.
• To develop a prototype implementation for Data
  Processing Unit (DPU)
• DPU initiates the requests for data from the data
  acquisition unit, collects the data and displays
  and/or archives it.

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Technologies used

• Pressure Transducer (Unidatas 6508)
• Field Programmable Gate Array (Alteras Stratix
  FPGA)
• Analog-to-Digital converter (TIs TLC02820ACN)
• IEEE 802.11b Wireless antenna (DLinks DWL-810)
• Java

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Field Programmable Gate Arrays

• Large number of simple logic blocks
• Number of I/O ports
• Custom hardware
• Reconfigurable
• Low cost

FPGA development board
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IEEE 802.11b (Wi-Fi)

• Layer 2 protocol for Wireless LANs
• Maximum throughput of 11Mbps
• Maximum range of 150-200ft but
• can be extended to several miles
• using high gain antennas
• Widely accepted standard

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DAU Prototype Implementation
FPGA Altera Stratix
A/D Converter
Antenna
Dlink Ethernet wireless bridge
Unidata Pressure sensor
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DAU Implementation (Contd.)

• Device driver for TIs AD converter
• Standard 32 bit hardware for FPGA with Networking
  support
• Server program running on FPGA listening to data
  requests

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Water level calculation

• Analog voltage output from sensor is 0 to 2.55 V
• Range of pressure sensor is 0-5m or 0-16.4ft
  (20mm resolution)
• If digitized value from 8-bit AD converter is X
  then
• depth of pressure sensor (X/255)5 meters
  or (X/255)16.4 ft
• Water elevation elevation of the ground -
  length of the cable depth measured by pressure
  sensor

Measuring point
Land Surface
Length of cable
Groundwater Level (elevation)
Water Level
Length measured by Pressure transducer
Pressure transducer
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DPU Prototype Implementation

• Graphically displays the data in real-time
• Archives the data in a MySql database
• Provision to view the data for a specific period
  of time

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Cost table for DAU
Solinst Telemetry System costs 2500 per
node Retail price, academic discounted price is
often lower
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Challenges

• Cost
• Battery Life
• Line of Sight
• Flexibility

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Related work

• Berkeley Motes
• For massively distributed sensor networks
• Power, sensing, computation and communication in
  a cubic millimeter
• High Performance Wireless Research and Education
  Network
• Concentrates on wide range IEEE 802.11
• Reconfigurable sensor networks
• Applied to micro climate monitoring
• Bellman Ford routing algorithm for line of sight
  problem

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Demo
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Questions?