Rainwater Harvesting Using Bunds: A Nature Based Solution

Ditch expensive solutions for contour bunds - cost effective holes in the ground that capture rainfall.

Drink up the rainwater by Nivedita Bansal and Aalia Burman

Access to clean water for drinking and sanitation is a growing challenge in India. 1 in 2 people in the country suffers from high levels of water scarcity, and 70% percent of drinking water is polluted to some extent. Lakes are growing smaller, rivers are running thinner, and groundwater is disappearing. The issue of water scarcity impacts various aspects of the population’s quality of life, not only drinking water availability but also sanitation and the risk of waterborne diseases. Industrial and agricultural activities put a strain on water resources and pollute important sources of freshwater. Water used for irrigation also depletes freshwater stocks, especially in areas where non-native cash crops like sugarcane and cotton are being cultivated.

By Ritesh Arya

The states that suffer the most under chronic water shortages due to water mismanagement are Rajasthan, Gujarat, Haryana, Punjab, Uttar Pradesh, Madhya Pradesh, Maharashtra, and Karnataka. Sustainable water management is essential for India to work towards SDG 6 (Clean Water and Sanitation) and its improvement will have a plethora of positive knockdown effects. One nature-based solution to combat water shortages is rainwater harvesting using bunds. Bunds have been used for millennia by tribal and agrarian communities, and act as a simple less expensive solution that can be implemented on a subsistence level.

Bunds as a rainwater harvesting technique

Water scarcity poses the biggest threat in Northwestern India, due to the region’s natural aridity. Furthermore, states with more naturally occurring freshwater, struggle with depleted water reserves and groundwater levels as well, due to the use of water-intensive crops. Harvesting rainwater has the potential to significantly alleviate water scarcity.

One method of rainwater harvesting is the construction of bunds. Bunds are ditches, embankments, or other structures to control the direction of surface runoff and collect rainwater. Rain is collected during the monsoon season to be stored and kept ready to be used during drier periods or to replenish wells. It allows rural communities to have an additional source of water during the dry season, apart from the groundwater. Furthermore, agricultural systems that rely heavily on rain can be managed more sustainably through the collection of rainwater, as this reduces their dependence on rainfall patterns. This method uses heavy rainfall during the monsoon season to make it possible to recharge groundwater or store water for the dry season.

Bunds: A nature-based solution

Bunds are a nature-based solution because they don’t increase pressures on the environment and instead harness natural processes to combat socio-economic issues. They can help mitigate the effects of lower groundwater levels and water scarcity during the dry season. Additionally, they prevent water from being lost through surface run-off and instead allow for reservoirs to be recharged. In periods of intense rainfall, this method can also reduce the risk of flooding, which can be caused by surface run-off from slopes, whilst storing the water for when it is needed. Lastly, this method is more eco-friendly, as constructing bunds usually utilizes land that humans have already transformed and doesn’t require additional land to be cleared.

The role of bunds in ecosystem restoration

Building bunds reduces surface runoff while at the same time increasing soil moisture during the drier months. Reducing surface run-off prevents sudden flooding which can save both human and animal lives. Surface run-off has increased due to unsustainable land management and an increase in urban and industrial areas, altering the natural water cycle. Reducing surface runoff by capturing the rain, counteracts the negative effects of human activities (such as deforestation), which can improve ecological balance. Thus, by using bunds, some of the side effects of human activities can be combated and the hydrological equilibrium can be restored. Furthermore, human activities have greatly altered the hydrology of certain areas and the river ecosystems. Rainwater harvesting reduces the water retrieved from rivers and groundwater, this decreases stressors on the environment.

Benefits to society

This method can aid in raising the groundwater table which would increase water availability in rural communities. This has many knockdown effects, such as more income from agriculture, less hunger, and a higher rate of education.

Benefits of rainwater harvesting using bunds

As an example, about 80% of groundwater in Nuh, a district of Haryana, is salty. Water scarcity, especially during the dry season, is very common. Many people face difficulties feeding their families as agriculture is limited due to the lack of water. Reduced access to sanitation is also an issue. To come by water, large amounts need to be paid or inhabitants have to walk long distances. Moreover, lack of water gravely limits agricultural production which is already impacted by a high salinity. By increasing the collection of rainwater, the inhabitants of Nuh have more freshwater available for drinking and agriculture.

Bunds are a simple and relatively cheap model of rainwater harvesting that gives independence to rural inhabitants. More available water boosts agriculture and improves food security, as it reduces irrigation costs and provides a higher success rate with crops. Depending on the crop, some small subsistence farms may be able to harvest twice the usual yearly yield by incorporating bunds. It is a sustainable approach because it increases the likelihood that agriculture can be maintained in the future, as there is less pressure on water bodies and groundwater.

Are they a sustainable option?

One of the main pitfalls of rainwater harvesting is its quality. In areas with high levels of air pollution, drinking rainwater would be detrimental to one's health. Arsenic contamination poses a big risk, mainly in Bihar, Jharkhand, and West Bengal, with the Bureau of Indian Standards (BIS) having declared a maximum amount that can be present in water before becoming harmful. This can be combated by monitoring rainwater parameters, in the case of large collection facilities, and by filtering the water. The last point being difficult to implement on a smaller scale.

Rainwater harvesting is a promising solution but falls short when the drivers of water shortages are not addressed. One approach to addressing drivers is increasing the efficiency of industrial processes that use water. For example, Tata Chemicals reduced their groundwater consumption immensely within a year by making the recycling of wastewater more efficient. Moreover, tighter monitoring and better management of wastewater can significantly lower the need for more water to be added. Processes that require water, whether agricultural or industrial, must become more efficient and less wasteful.

Water scarcity needs to be tackled from all sides due to the acuteness of the issue. For families and communities, rainwater harvesting through bunds can increase their independence and add a level of stability, therefore this approach would be based on a smaller, decentralized scale. Whereas reducing water wastage and improving recycling in agriculture and industries, would impact water availability on a larger scale. It is also important to mention that a large portion of agricultural practices are extremely water-intensive, depending on the crops and techniques used. Thus, to adapt to reduced water levels and aim at reducing water scarcity agricultural processes must become less wasteful and less water-intensive crops should be used.

To make water management more sustainable it needs to be improved from all sides. For example, using rainwater for agriculture does reduce the strain on groundwater but by continuing to grow water-intensive crops instead of ones better suited to the environment, the issue of water scarcity is not solved. Unfortunately, extracting groundwater and growing water-intensive crops is more financially favourable for farmers, therefore governmental actions must be taken to make less water-intensive crops more favourable. Lastly, the conservation and restoration of ecosystems that are essential for providing and filtering freshwater can greatly improve their ability to retain water, and therefore also contribute to improving the situation.

Pilot projects using bunds

Water scarcity is tackled by a variety of organizations and pilot projects using different approaches. Some are more focused on improving conditions in rural communities, whereas others focus on transforming agricultural processes to become more sustainable. Unfortunately, bunds are not widely included. It is necessary that, especially on a village-scale, bunds are incorporated to increase the villagers’ independence. By sharing this technique with people, they can continue using it themselves without the need for further help from the organizations. We will briefly discuss 2 programmes that already include bunds and some other ones that prioritize other methods of rainwater harvesting and water management.

Certain programs incorporate bunds into their work. For example, the Integrated Watershed Management Programme (IWMP) implements bunds in their rural development projects. Furthermore, the Mozda collective, an NGO that tackles pollution, water management, energy, and women’s rights, helps families build bunds of the right size and determine the best location for them.

Jal Shakti Abhiyan (JSA), is a water conservation campaign by the government that focuses on rainwater harvesting in regions with high levels of water scarcity. The campaign promotes sustainable water conservation, and returning water bodies to their previous states. Furthermore, Atal Bhujal Yojana (ABHY) (Groundwater Management) aims to engage local communities to better manage groundwater stocks.

Another example is the S M Sehgal Foundation and the Millennium Alliance which installed wells in schools throughout the district and informed the community of their proper usage. Rainwater was collected on top of roofs and then used to reduce the salinity of groundwater. This not only supplied students with water but also allowed them, mainly girls, to attend school, which benefits the communities’ overall education. From these examples, it can be seen that rainwater harvesting is one solution to the problem but to make a significant impact other efforts such as education programs and the implementation of infrastructure for water management are needed.

An example of a more unusual pilot project can be found in the state of Gujarat, where solar panels were built over a canal. This reduced evaporation and allowed for energy production. The project was a big success.

References

Admin. (2023, November 23). How is India managing water stress in rural areas? S M Sehgal Foundation. https://www.smsfoundation.org/how-is-india-managing-water-stress-in-rural-areas/

The United Nations World Water Development Report 2024: Water for prosperity and peace. (2024, March 23). ReliefWeb. https://reliefweb.int/report/world/united-nations-world-water-development-report-2024-water-prosperity-and-peace-enarruzhhiitdeko?gad_source=1&gclid=Cj0KCQjwrKu2BhDkARIsAD7GBouD-4fZqloSNgllhTY8eN2zqM5AKlVTeQAXx45FTvJo9JQAD2KTox4aAubFEALw_wcB

Chaudhary, M. (2024, February 26). India’s thirst for improved water security | East Asia Forum. East Asia Forum. https://eastasiaforum.org/2024/02/27/indias-thirst-for-improved-water-security/

Rain Water Harvesting (RWH). TamilNadu Water Supply And Drainage Board. https://www.twadboard.tn.gov.in/rain-water-harvesting-rwh

Guidelines for Urban Water Conservation Jal Shakti Abhiyan. Ministry of Housing and Urban Affairs Government of India. https://ejalshakti.gov.in/JSA/jsaContent/GuidelinesforJalShaktiAbhiyan.pdf

Buckley, R. (2023, May 30). Sustaining our Streams: The Power of Water Harvesting in River Restoration. Norfolk Rivers Trust. https://norfolkriverstrust.org/water-harvesting-for-river-restoration/

Jitendra. (2020, March 11). Water-stressed in India: How bunds helped farmers in Mahoba put drought behind. Down to Earth. https://www.downtoearth.org.in/water/water-stressed-in-india-how-bunds-helped-farmers-in-mahoba-put-drought-behind-69705#:~:text=Construction%20of%20bunds%2C%20however%2C%20helped,Kharif%20crops%2C%E2%80%9D%20said%20Prajapati

Banayad, C. (2012, April 30). What’s a Bund? Innovative water conservation in India. Global Greengrants Fund. https://www.greengrants.org/2012/04/30/whats-a-bund-innovative-water-management-in-india/

World Bank Group. (2022, March 18). Communities lead India’s groundwater conservation efforts. World Bank. https://www.worldbank.org/en/news/video/2022/03/18/communities-lead-india-s-groundwater-conservation-efforts