The Enduring Importance of Tank Irrigation Systems
Ancient water harvesting systems, such as those from the Indus Valley Civilization (~3500 BCE), have been vital for irrigation and climate resilience, especially in arid regions. One such prominent system in South Asia, called tank irrigation, initially thrived through community management but declined post-independence due to colonial policies and neglect in Sri Lanka and India. This study evaluates current policy frameworks and rehabilitation programs to enhance the resilience of these systems in India, develop strategies for their protection and adaptation to climate change, and integrate global lessons for sustainable development.
The tank cascade system (TCS) in South Asia, including those in Dholavira from the Indus Valley Civilization dating back to around 3,500 BCE, underscore the region’s enduring water management and tank irrigation tradition. These early systems were marked by sophisticated designs featuring large reservoirs, step wells, and channels, setting a precedent for sustainable water management through community involvement. This tradition continued and evolved throughout history, notably with the cascading tanks, designed and constructed over 2,000 years ago by rulers, philanthropists, and local communities due to their extraordinary engineering and managerial skills.
Even though these old systems are from generations ago, they have degenerated despite age due to unwarranted political interventions and changing socio-economic dynamics. All this eventually started during the colonial period (early 19th century) when water policy shifted from minor irrigation (having irrigated areas 10,000 hectares). These shifted policies focused more on revenue generation from these traditional structures instead of their protection and context-based applications. As a result, the ownership of common pool resources, such as tank systems, deteriorated, and village-level institutions disappeared. This management transfer from local communities to colonial governments further exacerbated the decline of traditional water management practices.
Reviving Tank Irrigation Systems: Challenges and Opportunities
Despite the significant decline in tank irrigation, pilot projects for tank rehabilitation have had limited success in achieving sustainability under current climate conditions. Tank irrigation systems are crucial for adapting to extreme weather, including floods, droughts, and heat waves, replenishing groundwater, reducing soil erosion, and ensuring reliable water supplies. Traditional water harvesting technologies support 17 Sustainable Development Goals (SDGs), including clean water access, hunger reduction, gender equality, and climate action. Integrating AI and machine learning in water management benefits disaster response, while eco-tourism aids system maintenance and cultural awareness.
The analysis showed that the effectiveness of tank rehabilitation programs was often influenced by the priorities and capacities of the implementing agencies. As a result, strategizing revival on a case-to-case basis becomes difficult in addition to changing political and socio-economic set-ups. By the early 1980s, rehabilitation programs had been initiated in support of the government, non-government, and foreign organizations across India’s semi-arid and dry states. Most of the interventions were made via repairing tank structures as a whole or part, watershed or rural-landscape development, and rebuilding institutional management systems.
The field experience from other studies has shown that not considering the community’s perception while designing rehabilitation and revival programs may lead to a conflict of interest. For instance, in Tamil Nadu, degraded tanks provided several services to the village communities, such as livestock management, obtaining silt from the tank bed for their farm, etc. Under such a context, reviving tanks may be futile as it might adversely affect communities currently benefitting from them. Similarly, command area farmers and tank bed farmers were observed practicing flood irrigation in silted (degraded or unmanaged) tanks. Reviving tanks in this context might go against the interest of the tank bed farmers (primarily landless) because the intervention in terms of de-siltation, catchment treatment, etc., may displace them.
Coherent to these contexts, understanding the varying needs and perspectives of different stakeholders is crucial for the success of tank rehabilitation programs. Designing policies for modernization and rehabilitation programs must follow Participatory Rural Appraisal (PRA) in the village context to contemplate local perspectives. Nonetheless, the Water User’s Association (WUAs) must be part of the project in urban and rural contexts to collect wide-ranging inputs before the program implementation.
Integrating Traditional and Modern Water Harvesting Techniques
Despite several advances in rehabilitation programs across decades, threats and challenges continued to exist. A significant criticism observed in the rehabilitation works is its consideration as a single-time activity. This act has widely given rise to the absence of post-rehabilitation backing, such as for minor structural repairs or modifications, provisions of getting additional funds, and further assistance in training and capacity building. Consequently, the program fails to achieve its objectives fully and does not deliver the intended benefits to the communities.
There is a need to bring policy changes considering local and regional variabilities with a primary focus on addressing collapsed livelihood opportunities for local communities (such as landless farmers), food insecurity, environmental water mismanagement, and regional and ecological imbalances in the vicinity of tanks. More specifically, strategies for real-time tank policies need to be introduced in the rational way of drafting policies.
Integrating traditional knowledge with modern practices can further support these measures, ensuring the long-term ecological and hydrological integrity of tank irrigation systems. A coordinated effort involving key organizations is proposed to effectively address tank system management and rehabilitation, integrating service providers, facilitators, and users. Service providers, such as the Ministry of Jal Shakti (in India) and State Water Resources Departments, can develop and implement national and state-level policies, respectively, with the Central Water Commission providing technical guidance. Service facilitators, including local NGOs, can ensure community involvement and act as intermediaries between the government and local communities. Service users, such as Tank User Groups (TUGs), Water User Associations (WUAs), and local communities, are crucial for the success of these programs, necessitating their active participation.
Harnessing the Global Potential of Traditional Water Harvesting Systems
Traditional water harvesting systems, exemplified by the cascading tanks and analogous methodologies worldwide, are paramount in advancing societal well-being. They may make a substantial and demonstrable contribution to socio-economic development, aligning with the 17 Sustainable Development Goals (SDGs). These systems contribute to improved water access, increased agricultural productivity, community empowerment, and gender equality while exhibiting notable resilience to extreme climatic events.
Tank cascade systems (TCS) and similar traditional water harvesting techniques can help bring climate change resilience in various ways. They can mitigate floods by collecting and storing more precipitation, contribute to drought resilience by offering a steady water supply during dry spells, and enhance heatwave adaptation by providing access to water for cooling and irrigation. They can also reduce a community’s reliance on external water sources and enhance ecosystem services like soil conservation and groundwater recharge.
Integrating traditional knowledge with modern technologies, such as GIS, remote sensing, and artificial intelligence, can optimize the efficiency and effectiveness of these systems. AI-ML techniques can enhance TCS functionality by optimizing water distribution and improving predictive capabilities for extreme weather events, transforming traditional water harvesting practices and fostering more resilient and efficient management of water resources.
The rehabilitation and revival of traditional water harvesting systems offer significant visions for global water management, environmental sustainability, and climate resilience. By combining ancient knowledge with modern innovation, engaging local communities, and providing supportive policies and institutional frameworks, regions around the world can enhance water security, build climate resilience, and achieve sustainable development. The lessons from India’s experience with tank irrigation systems can inspire similar efforts to revive traditional water harvesting practices globally, contributing to a more water-secure and sustainable future.
