Water Resource Management & Acoustic Capacity & Capability Building – A New Perspective based on the Underwater Domain Awareness (UDA) Framework
By: Dr (Cdr) Arnab Das
India has 2.4% of land area, but 18% of population and has access to 4% of the global water resources. In 2011, it has been declared as water stressed and an estimated 600 million population are water deprived. Even the global scenario is equally bleak, and 1.1 billion people worldwide lack access to water and a total of 2.7 billion find water scarce for at least one month of the year. Inadequate sanitation is an added problem with over 2.4 billion people, being exposed to diseases like cholera and typhoid fever, and multiple other water-borne illnesses. The tropical region has roughly 40% of the global population and more importantly, it houses majority (over 55%) of the children under five. The critical aspect of the statistics is that the rate of population growth in the marginalized tropical countries like from Africa and Asia is far higher than the temperate region. The governance in the marginalized countries is a major issue and could lead to catastrophic consequences. The booming population, rising economies and threatened biodiversity is a deadly mix, especially in the tropical regions that have their unique challenges. The tropical regions have significant opportunities, however, the poor governance mechanism only overwhelms them with challenges.
“Good management of water resources will bring more certainty and efficiency in productivity across economic sectors and will contribute to the health of the ecosystem. Thus, water resource management and water quality management need a nuanced approach.”
The tropical region has some unique characteristics, and it is important to discuss these, prior to attempting any management initiatives. The conventional approach to importing technology & knowhow from the west (temperate region) has failed miserably due to this disconnect in our appreciation of the unique tropical characteristics. We can categorize the tropical characteristics into political, economic and physical, for the ease of analysis. The politically pre-modern states in the tropical region, means that the governance mechanism is still evolving. The extra-regional powers, particularly from the west, continue to meddle in their domestic politics and limit their ability to put an effective policy framework in place to manage the challenges and opportunities. Geopolitics and geostrategic events drive the domestic policy initiatives at the cost of long term strategic national interests. Political leadership, are too dependent on external support for their political survival and thus, get managed by their evil design at the cost of national interest. The politics drives economic prudence. The west continues to push their products in these markets and refuses to share the technology & knowhow, keeping them dependent in the long term. More often than not, these technologies are discarded and outdated technologies being phased out in their own markets, due to sustainability concerns and obsolescence. The west driven political and economic structures have ensured complete erosion of the traditional and indigenous practices that are deeply connected, to the local site-specific ground realities.
The tropical region has high temperatures and equally high rainfall, compared to the other regions. This leads to very high siltation in the water bodies due to rapid sediment flow. The poor governance mechanism ensures high anthropogenic activities by the local communities leading to reduced forest cover along the freshwater systems, resulting in enhanced siltation. Heightened economic activities with least appreciation of the local ecosystem and traditional practices, further raises sustainability concerns.
” he rapid urbanization and unregulated industrialization, has led to enhanced pollution of the water bodies and also depletion of the groundwater. India uses more than 90% of groundwater for irrigated agriculture. Remainder of the 24 billion cubic meters of groundwater supplies to 85% of the countries drinking water. Thus, close to 80% of India’s 1.35 billion population depends on groundwater for both drinking and irrigation. “
The freshwater systems like the reservoirs, natural lakes and river systems in the tropical region are highly silted. In India the sediment deposition is of the order of 50%. This leads to flooding during the monsoons and water stress during dry seasons. The urban centers have started facing severe crisis, as the near complete concretization and poor drainage systems, has led to massive urban flooding and minimal groundwater recharging during monsoons. The level of aquifers has gone down dangerously low with frequent and prohibitively high cost of boring for domestic users. Poor waste management in the urban centers has further led to serious contamination of the groundwater to dangerous levels.
Sediment management of the freshwater systems will require precise sediment classification. The sediment classification in water bodies will require acoustic survey techniques using sonars. The tropical region ensures sub-optimal performance of the sonars of the order of 60%, due to random temperature fluctuations and corresponding distortions in the sound velocity profile. Thus, Underwater Domain Awareness (UDA) is a big challenge to plan any meaningful management of the underwater resources both in the marine as well as freshwater systems. Import of sonar systems from the west in the absence of indigenous field experimental R&D to compensate for the local site-specific characteristics is a serious issue.
The sediment classification is a critical pre-requisite to plan any de-siltation as the specific dredging method will depend upon the type of silt ranging from hard rock to soft mud. The cost of dredging varies significantly based on the nature of silt and could be prohibitive at the high end of the spectrum. The efficient planning of the sediment removal will be highly sensitive to the accuracy of the sediment classification effort. The bigger issue is the sediment disposal. The viability of the entire sediment management has to be interlinked to sediment removal and disposal. The end user of the removed sediment will require detailed prior inputs on the sediment to even budget the cost of the sediment removal & disposal. Typically, the Government being the owner of the water bodies, does the heavy lifting, in terms of paying the entire cost of sediment removal and disposal. However, in developing democracies and given the socio-economic realities, such cost is politically unviable.
“The sediment classification will also make sure that the right sediment layer is removed, depending upon a recharge or a storage reservoir. If not done appropriately, the storage reservoir could become a recharge reservoir and vice-versa. Such mistake could be extremely costly and highly counter-productive.”
Establishing the appropriate value for the sediment and the end user sharing the cost of sediment removal will make a significant impact on the viability of the entire effort. Thus, sediment classification using acoustic means, will be the most important first step. Hydraulic suction for sediment removal in case of soft silt will ensure massive savings, compared to dredging (typically used for hard bottom). Surveys undertaken by the author has revealed that large parts of the tropical region have soft silt and does not require expensive dredging equipment for sediment removal. However, it has been observed that sediment classification is seldom used, prior planning the sediment removal, leading to inefficient and ineffective sediment management. The soft silt can be used for brick making using mega plants next to the water bodies. Developing countries require massive amounts of bricks for infrastructure development and thus, will provide an ecologically sustainable and economically viable alternative for sediment disposal. In this case, the builders and infrastructure companies can easily share the cost of sediment removal. Many experts have suggested transporting the removed sediment for farming, as it is very fertile soil. The small farmers in India with small land holding, will find it extremely difficult to pay any amount even for logistics of transporting the sediments and also the small size of their land holding will make it unviable from the logistics, even if the government is doing the heavy lifting. The small window of opportunity between the Rabi and the Kharif crops, is not enough for the sediment disposal to happen in reasonable quantity. If the sediment is analyzed properly using acoustic means prior removal, a detailed and effective sediment disposal plan can be formalized. Such efforts, will not only make it viable, but also allow sustainable practices.
The domestic freshwater needs to be assessed for its quality prior human consumption. An online real-time monitoring is extremely critical to ensure that this water is fit for human consumption. Freshwater usage varies from industrial use to human consumption, starting from drinking to cleaning and agriculture. All these usages do not need the same quality of water and leaves a significant opportunity to calibrate the application and quality. In India and many parts of the world, it is observed that high quality freshwater fit for human consumption is being used for industrial and agricultural use, whereas many people are unable to get access for reasonable quality of water for drinking. Thus, water quality has to be an integral part of the water resource management to make sure that the water stress is mitigated effectively.
“.Thus, Underwater Domain Awareness (UDA) becomes the corner stone of any initiative. UDA framework with effective policy & technology intervention in the tropical littoral waters will require appropriate focus on the acoustic capacity & capability building. The ongoing developments in the Digital construct, needs to be taken to the underwater domain for effective governance. “
The precise sediment classification will also allow accurate water quality assessment as well, and that will allow appropriate usage of the sediment post removal. The underwater sensing and signal processing will be the key requirements for acoustic capacity & capability building.
Effective sediment management will help multiple sectors, like hydro-power generation, flood control, drought relief, navigation for Inland Water Transport (IWT), port management, dam safety and many more, apart from freshwater resource management. We are seeing a lot of technology and knowhow being imported from the Nordic countries. It is important to note that these are polar nations with minimal appreciation of the tropical littoral conditions. The corporates from these nations are more interested in exporting their heavy dredging equipment at high cost, with least regards for its applicability in our waters. Acoustic survey and sediment classification, is the critical pre-requisite to make sure, we use the appropriate sediment removal method. Indigenous effort in acoustic capacity & capability building to mitigate the tropical littoral challenges will be a strategic requirement to make sure we are able put in place a nuanced approach.
“The Underwater Domain Awareness (UDA) framework proposed by the Maritime Research Centre (MRC), can comprehensively address the challenges and opportunities of the water resource management requirement in the tropical littoral waters. “
About The Author
Dr (Cdr) Arnab Das
Dr (Cdr) Arnab Das, Director and Founder of MRC, Pune. Dr Das is a former Naval officer with 2 decades of active services and PhD holder from IIT Delhi with specialization in Underwater Acoustics. He has worked on several projects and has a plethora of publications to his credit.