Systematic and real-time monitoring of quality and quantity of surface water using geospatial technology
INTRODUCTION
Sustainability of any form of life on the earth is linked to water. The availability of fresh water is crucial in the survival of humanity. Therefore, it is vital to assess the available water resources and determine the water budget. Since there is limited availability of freshwater resources, effective management is critical in maintaining the demand for good quality and the adequate quantity. Water management will be effective when the system is smart in real time monitoring. Like any natural resource management, geospatial technologies have a significant role in making the system smart.
Information about water quality is fundamental to determine the accessibility and effective distribution of potable water for domestic, irrigation, aquatic farming and even recreational activities. However, existing water quality information coverage across India is limited and is field based data. Satellite remote sensing is suggested as a potential technology solution to provide measurements over a wide area at regular intervals. However, advances in the use of remote sensing for water quality are primarily restricted to the research domain. High spatial and temporal resolution satellite sensors along with moderate spatial resolution sensor with enough spectral information coverage like SPOT, ALOS, LANDSAT are available to generate water quality parameters that are significant in water resource management. Therefore, with operational satellite sensors and technologies such as cloud computing, information and communication technologies (ICT) and Internet of Things (IoT) provides opportunities for developing remote sensing-based operational monitoring capabilities for a country like India.
BACKGROUND
India is rich in water resources, being endowed with a network of rivers and is blessed with snow cover in the Himalayan range that can meet a variety of water requirements. However, population explosion with increasing demands of irrigation, human and industrial consumption, the available water resources are getting depleted, and the water quality has deteriorated. Indian rivers polluted due to the discharge of untreated sewage and industrial effluents. The country is blessed with high precipitation, with the southwest monsoon accounting 75% of the annual rainfall. However, the various terrain conditions with an upland plain (Deccan Plateau) in the south, flat to rolling plain along the Ganges, deserts in west, the Himalayas in the north makes it vulnerable to flooding during monsoon and droughts in summer. Though flood inundation maps and drought zonation are available, it is crucial to systematically specify on water availability at a particular time in a surface water body. During summer, this helps governments to plan for droughts. After the flood recedes, a reservoir may get accumulated with sediments that can reduce its volume leading to changes in water quality. Hence, seasonal fluctuations can alter the water quality, and it needs proper database. This database should be available to the stake holders in a real time. Consequently, smart solutions of digital nature integrated with geospatial technology are the stopover. SWM infrastructure includes sensors, smart meters, monitors, GIS and satellite mapping, and other data sharing tools in water management integrated to real-time solutions.
MOTIVATION
India is not water-starved but storage-starved. There are thirteen major river basins (an area more than 20,000 square kilometers) in the country, which occupy 82.4% of total drainage basins, contribute 85% of the total surface flow and house 80% of the country’s population. There are complete arid areas where evaporation equals rainfall and hence no surface-flow. The medium and minor river basins are mainly in the coastal area. Few regions in India go dry during the summer seasons and leads to scarcity of water resources leading to an even interstate fight. Additionally perennial rivers are polluted due to the industrial and human-induced activities, deteriorating the quality of the water to an extreme level which does not even support the existence of life in the rivers. Therefore, it is evident that there is an immense need for assessing the water quality and quantity at national level.
The water sector has a complex interactive operation between water resources and environmental systems and the socioeconomic. The knowledge of the status of water storage in the country at a real-time will enable efficient management of water resources for domestic, industrial and agricultural activities.
AIM
The central aim is to generate a GIS based stand-alone real time surface water management system for India involving both water quality and quantity. More succinctly the project is termed as ‘sense4water’.
The proposed aim will be achieved by fulfilling the following objectives. The objectives will be fulfilled for three large dams or reservoirs of India during the study period (60 months) and the objectives will be extended to all other surface water bodies in India during the extended period to achieve the goal.
Hence the objectives of the proposed project are
1. To generate algorithms to extrapolate field measurements to derive spatial maps on water quality parameters in large dams and reservoirs
2. To estimate water quality parameters using remote sensing data and validate with field measurements
3. To develop a model that generate time series maps on various water quality parameters using remote sensing data.
4. To develop a real time water quality monitoring system integrating remote sensing data and field data
5. To derive a predictive water quality algorithm for future forecasting.
6. To estimate the volume of the water bodies integrating remote sensing techniques and real time adaptive sensors (Corner reflectors)
7. To develop an algorithm that can create a smart platform to measure the spatio-temporal variations in volume of water stored in various surface water bodies including tanks, lakes, and reservoirs for Smart Water Management.
8. A predictive algorithm for future forecasting on water quantity
9. To develop a web based GIS platform integrating real time monitoring of water quality and quantity.
TECHNIQUES
By conducting the reconnaissance study of the proposed reservoir unit, facilities would be set up to carry out the bathymetric survey. The bathymetric survey would aim to establish high-resolution bathymetric information for the reservoir. It would be carried out implementing state of the art geophysical instruments and logistics. However, to understand sediment layers as well as its source of the sediments in the reservoir, two different techniques, namely vibra-coring technique and acoustic technique, would be performed. Also, an algorithm will be established to accurately simulate the temporal variation of silt and sediment deposit in the reservoir against time. After estimating the volume of the siltation in the reservoir, the total volume of the reservoir may be established in terms of its water-retaining capacity. We will be able to render a 2D illustration of the reservoir with the help of this information’s we will be able to accurately estimate the amount of water that can be being stored. Further, radar corner reflectors would be designed to reflect the microwave waves emitted by radar sets back toward the radar antenna such that a holistic integration between the the corner reflectors and Sentinel-1 satellite sensors can be established. This would finally enable a near real-time water quantity monitoring module.
Inland surface water bodies are exposed to cycles of low flow or drought conditions, interspersed with intense periods of rainfall leading to flash floods in high relief terrain or extended and extensive floods in flat terrain. Flood results in large fluxes of suspended sediment, dissolved organic material, salt, nutrients and contaminants that needs to be monitored as parameters of water quality. During floods algal‐related measurements are less relevant as water turbulence and the re‐suspension and dissolution of soil materials prevents algal growth. Similarly during low flow conditions, algal growth may need monitoring so is suspended sediments and dissolved organic matter. Monitoring rapid changes in water quality during extreme events poses challenges to any monitoring method. Therefore, there is an opportunity for satellite based remote sensing techniques to improve inland water quality monitoring coupled with sensor based real time monitoring to provide synoptic, consistent and comparable data unobtainable through field based laboratory monitoring practices.
PILOT IMPLEMENTATION
First phase testing of near-real time water quantity monitoring has been carried out. Due CoVID-19 pandemic related restrictions, the pilot implementation couldn’t be carried out in India. The industry expert of our project team assisted us with the same by testing the innovation at the Michigen Lake in the US. Integration of Corner-reflectors with the Sentinal-1 sensors were carried out to derive the results as shown in the table below. The next phase of conducting water quality assessment is in the run and shall soon post the tangible yields out of it to finally go on with creation of the real-time analytics dashboard.
TEAM
The team is lead by Mr. S Prem Kumar, a National Geographic Young Research winner and PhD Researcher at the Indian Institute of Technology, Guwahati and co-lead by Mr. Chandan Dey, CSIR – Senior Research Fellow and PhD Researcher at the CSIR – North East Institute of Science and Technology, Jorhat. Both these aspiring entrepreneurs are guided by Prof. T G Sitharam, Director, Indian Institute of Technology, Guwahati, as the Advisor and Prof Franz J Meyer, Chief Scientist, NASA – ASF as the Industry Expert.
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