AUTOMATIC WATER LEVEL MONITORING SYSTEM EWLR-101

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1 FEATURES AUTOMATIC WATER LEVEL MONITORING SYSTEM EWLR-101 INTRODUCTION Monitoring of ground water table has assumed great significance in view of depleting ground water reserves. As government and environmental groups take more interest in monitoring and working out schemes for conservation and recharging of sources of ground water, monitoring of water table is being given greater priority than ever before. Encardio-rite automatic water level recording systems provide a variety of solutions ranging from unattended monitoring of a single borehole for use by industry to statewide monitoring of hundreds of boreholes from a central location by state or national level organizations. MONITORING OF WATER TABLE To monitor the water table at a particular location either an existing well/borehole is used or a borehole is drilled down to the aquifer that contributes most to the water table. A casing pipe is installed in the borehole to prevent the borehole wall from collapsing. At the level of the aquifer the casing pipe is replaced with highly porous filter. The filter in this case can even consist of a section of slotted pipe covered with geotextile to prevent soil particles from clogging the borehole. The level of water in such a borehole or well corresponds to the water table at that location. The water level is generally referenced to mean sea level and is known as the elevation of the water table. AUTOMATIC DATA LOGGING OF GROUND WATER LEVEL USING VENTED GAGE PRESSURE SENSOR The easiest method of automatic monitoring of water level in a well is to use a fluid pressure sensor. The pressure sensor is installed at a point below the minimum expected water level. Output of pressure sensor is proportional to the head of water above the pressure sensor and is known as the piezometric head. In geotechnical engineering, a water pressure sensor is generally known as a piezometer. Measuring water level with a pressure sensor is highly dependent upon the specific gravity of water at the location. Specific gravity of water that ideally should be 1.0 increases with increasing total dissolved solid content in water. For example, in coastal areas, water in monitoring wells can have a specific gravity as high as 1.1. This can result in a 10 % error in water level measurement.to get correct water level, reading from pressure sensor has to be corrected for specific gravity of water at that location. Encardio-rite model EPP-60V/EPP-30V vented gage pressure sensor For ground water monitoring, models EPP-60V and EPP-30V range of vented gage pressure sensors (also known as piezometers) are available from Encardio-rite. They are high accuracy devices incorporating the latest technology and are specially designed to measure water level or pore pressure in a borehole depending upon how the sensor is installed. A thermistor is also incorporated in the pressure sensor for measurement of water temperature. GSM/GPRS modem allow data to be collected remotely from hundreds of kilometers away. APPLICATIONS Reliable and economical. Quick remote access to data. Easy to install, simple to use and user friendly. Large data storage memory allows data to be monitored for longer time between retrievals. Weather resistant housing suitable for field deployment. Dataloggers with inbuilt Unattended ground water level monitoring. Picture 1 - Model EWLR-101

2 The outer body of these sensors is of stainless steel construction. It is therefore resistant to rusting or corrosion against several kinds of dissolved impurities found in water under field conditions. For saline water applications special sensor with additional protection are provided. Model EPP-60V is recommended for applications where maximum hydrostatic head (height of water level above piezometer location) over the sensor diaphragm is upto 20 m. Model EPP-60V is a vented gage pressure sensor and is to be used with an integral water proof four conductor signal cable with two vent tubes that connect the interior of the pressure sensor to the atmosphere at ground level. Picture 2 - Model EPP-60V pressure sensor Holding plate Datalogger with battery Sensor safety wire Pressure sensor specifications Range EPP-60V 0.010, 0.20 MPa (10, 20 m WC) Range EPP-30V 0.2, 0.35, 0.5, 0.7, 1.0, 1.5, 2.0, 3.5, 5.0, 10.0 MPa (20, 35, 50, 70, 100, 150, 200, 350, 500, 1000 m WC) Accuracy ± 0.1 % fs standard ± 0.05 % fs optional Repeatability ± 0.05 % full scale Long term stability ± 0.1 % full scale coefficient < 0.01 % fs/ C over 10ºC to 40 C sensor temperature Overload pressure 2 times full scale. Burst Pressure 3 times full scale measurement range - 20ºC to 70ºC accuracy ± 0.5ºC standard. (Higher accuracy option available) Overvoltage protection Each sensor conductor is protected by conservatively rated silicon transient voltage suppressors against high voltage transients. Protection IP-68 Dimension 30 mm x 160 mm (Ø x L) Cable Encardio-rite model CS-1102 two pair screened cable with Kevlar strength member and dual vent tube. Desiccant Indicating type silica gel in cartridges provided for drying air inside sensor and vent tubes. Desiccant will generally last for a minimum of 6 months. Sensor cable Piezometer Borehole Picture 3 - General layout A hydrophobic filter at desiccant chamber inlet is provided.

3 This allows the vented gage pressure sensor to eliminate the apparent variation in water pressure due to variation in atmospheric pressure. Provision of two vent tubes allows the interior of the sensor as well as the vent tubes to be purged clean with dry air (or nitrogen) during manufacturing or whenever required during use. It also allows any blockage in the vent tube that can give rise to incorrect pressure readings, to be easily detected. In case variation in water level above the pressure sensor is expected to exceed 20 m, the model EPP30V pressure sensor is to be used. It provides water level measurement up to very high levels and is recommended for higher hydrostatic head or piezometric pressure. Sensors upto 20 m WC are supplied with standard vented cable. Specify if higher capacity sensors are also required with vented cable. In practice the model EPP-60V/EPP-30V is suspended either from a bracket or a datalogger at the top of the borehole down below the minimum expected water level in the borehole using its own cable. Data logging The datalogger measures the output from the vented gage pressure sensor, calculates the pressure in terms of water column, temperature in units of degrees Celsius and stores the values together with the current date, time and battery voltage as a data record in its internal non-volatile memory. The model ESCL-10VT datalogger including the desiccant chamber, battery and the optional GSM/GPRS modem is mounted inside the borehole casing at ground level. The desiccant moisture trap ensures that the atmospheric air entering into the vent tubes is free from moisture that would otherwise condense inside the vent tube and the sensor interior giving rise to error in pressure measurement. The desiccant is supplied in easily replaceable plastic cartridges and is blue in color when fresh. A used up desiccant cartridge loses its blue color to become colorless at the end of its life when it needs to be replaced.the datalogger can be programmed to take a measurement from every 5 seconds to every 168 hours in linear or event sampling mode. However, the number of measurements taken per day should be kept to the minimum required as higher frequency of measurement drains the power supply battery at a much faster rate. Datalogger specifications Input EPP-60V/EPP-30V sensor with thermistor for temperature measurement. Resolution 18 bits. (Better than 1 mm for 70 m WC sensor) measurement range - 40 to +100 C measurement resolution 0.1 C Measuring interval 5 sec. to 168 hours. Measuring modes Linear or event sampling Memory capacity 8 MB Flash RAM. Can store 3,145,728 data points. Data output format CSV text file. Can be easily imported in many third party applications like Microsoft Excel. Communication port One RS-232 serial port. Interface cable for connecting to USB 2.0 port supplied as standard. Operating temperature range - 30 to 70ºC Built in clock Accuracy better than ± 1 minute/month. Displayed time resolution is 1 second. Power supply 2 x D size 3.6 V/19 Ah Lithium cells Battery life is more than 5 years for 4 measurement/ day and one transmission/ day with Lithium cells. Housing Corrosion resistant stainless steel, AISI grade 316L. Dimensions 50 mm dia x 500 mm Humidity 100 % Modem (In telemetry option) Quad Band GSM/GPRS/ EDGE, 850/800/1800/ 1900 MHz Antenna (In telemetry option) Built-in

4 DATA RETRIEVAL IN FIELD The data from datalogger in field can be retrieved directly either via a mobile phone readout unit using the Bluetooth interface or via Laptop through a special USB interface cable or Bluetooth interface. A single mobile phone/laptop with Bluetooth dongle/cable is used to collect data from any number of dataloggers as each datalogger data file is given a unique filename depending on datalogger or borehole identification number and the date and time the data was downloaded. The user or his technician has to physically go to each and every individual datalogger location after a predetermined time period or whenever required to collect (download) data from the datalogger. Readout/data retrieval using laptop running Microsoft Windows operating system The datalogger is supplied with application software that runs on the laptop with standard Windows XP or Windows 7 operating system. The laptop running the supplied datalogger configuration software can communicate with the datalogger through its USB communication port using an USB interface cable. The Laptop PC with the application software allows the user to set the sensor calibration coefficients, recording interval, datalogger or borehole code (identification tag numbers), sensor serial number, real time clock time etc. of the datalogger. LOGGER ESCL-10VT LAPTOP OR MOBILE PHONE WITH APPLICATION SOFTWARE BLUETOOTH 4 CORE CABLE WITH VENT TUBE EPP-30/60 V PRESSURE SENSOR USB/BLUETOOTH REMOTE USER PC Picture 5 - Automatic water level monitoring through laptop or mobile User can monitor readings and GPRS signal strength for diagnostic purpose. User can start or stop scan or can download data from Datalogger.The Laptop is also used to download the logged data from the datalogger into the memory, when required, as a CSV format data file that can then be transferred to the user's Server or a central PC for display as a table or chart for further analysis. Data is transferred to the server or central PC from the laptop using either the USB to serial cable supplied with the system or through Internet. If the user can provide a server or central PC with static IP internet connection and ftp server software at any central location, the data from the laptop can be directly sent to the server or central PC over the internet. However, this assumes that the borehole location is covered by a mobile phone service provider's network and the laptop is equipped with a suitable internet connection activated from that service provider. Mobile phone readout/data retrieval The datalogger is supplied with a mobile phone application software that runs on an Android mobile phone operating software and a Bluetooth interface. A mobile phone running the supplied datalogger configuration software can communicate with the datalogger using the Bluetooth interface. Picture 4 Data display on laptop PC

5 A detachable Bluetooth dongle is supplied with the datalogger. When fixed to the datalogger it permits Mobile phone specifications Display Capacitive touch 16M colors Display type Operating System 480 x 800 pixels Android OS V 2.1 or later Internal memory Expandable memory Bluetooth 1 GB minimum microsd v2.1 with A2DP communication with the mobile phone using the Bluetooth wireless interface. The user can carry a single Bluetooth dongle along with the mobile phone to establish Bluetooth connection individually with several model ESCL-10VT dataloggers. The mobile phone with the application software allows screen, the user to set the sensor calibration coefficients, specific gravity of water recording interval, datalogger The user will need to get a data SIM for each ESCL- or borehole code (identification tag numbers), sensor 10VT under a suitable plan from any mobile phone serial number, real time clock time etc. of the service provider depending on the volume of data datalogger. transfer expected from each datalogger. The mobile phone is also used to download the logged The user will also need to maintain a desktop PC at a data from the datalogger into the mobile phone central location configured to work as an ftp server. memory, when required, as a CSV format data file that This PC will need a static IP from any internet service can then be transferred to the user's desktop PC for provider. display as a table or chart or for further analysis. Data is transferred to a PC from the mobile phone using either the USB cable supplied with the mobile phone or using the Bluetooth interface if the PC also has a Bluetooth interface. The data from the mobile phone can also be directly sent to the client s central All the dataloggers in the network will be configured to send the data to this PC (also known as a server) at predetermined intervals. The collected data is kept as CSV formatted text files in specified folders on the PC which can then be viewed or analyzed using commercially available third party software. PC over the internet in the same way the data is sent from the laptop as described before. TELEMETRY OPTION - REMOTE DATA COLLECTION OVER GSM/GPRS NETWORK For a user organization that needs to monitor a very GSM NETWORK LOGGER ESCL-10VT (MOBILE NETWORK) WITH GSM/GPRS MODEM ENCARDIO-RITE WDMS SERVER large number of boreholes spread over a very wide geographical area, sending a technician to each and every individual borehole to collect data is a very expensive proposition and can prove to be a logistic 4 CORE CABLE WITH VENT TUBE nightmare. If all the borehole locations that need to be monitored remotely are covered by any GSM/GPRS mobile INTERNET phone service provider's network then the ESCL-10VT datalogger with telemetry option can be used to send data from the datalogger to a desktop PC at a central location. EPP-30/60 V PRESSURE SENSOR REMOTE USER PC Picture 6 - Automatic water level monitoring through GSM network

6 Picture 7 Data display on remote PC DATA PRESENTATION AND WEB ACCESS FOR password and access the graphs and tables using any USERS AT MULTIPLE LOCATIONS internet connected computer and a standard web The data on variation of water table collected from a browser like Microsoft Explorer, Google Chrome or large number of boreholes need to be presented as time Firefox etc. vs. water level graphs or as tables for visualization or In case a user does not want to host his own server, further analysis. Also the data may be required by a Encardio-rite can provide this as a service at a low number of people sitting at different geographical cost. This service is known as Web Based Data locations simultaneously. Monitoring Service (WDMS) and is available to users Authorized users from anywhere in the world can then throughout the world. login to the website using the supplied username and *All specifications are subject to change without prior notice. ENCARDIO-RITE ELECTRONICS PVT. LTD. A-7 Industrial Estate, Talkatora Road, Lucknow, UP , India p , f , geotech@encardio.com International: p DATA SHEET R05 C03