As the global demand for water continues to grow and environmental challenges become more pronounced, the imperative to embrace the principles of a circular economy becomes more and more important.  In the natural environment, stormwater originating from precipitation or melted snow is naturally absorbed into vegetation and soil. However, in urban areas, impervious surfaces such as roofs and asphalt surfaces prevent water infiltration into the ground. As stormwater flows over these surfaces, it carries pollutants with it, leading to potential environmental pollution, especially soil.

Along with the progress of climate change, the probability of more abundant precipitation also increases, which consequently leads to more and more frequent occurrence of torrential floods. Sustainable strategies, which include the application of sustainable "green" stormwater management systems, are gaining a significant role in promoting sustainable water management and solving today's critical environmental problems.

The traditional conventional approach separates urban agriculture and stormwater management into two different directions with different goals:

• Traditional approach: Historically, urban agriculture and stormwater management have been treated exclusively as separate concepts. Urban agriculture was primarily concerned with food production, while stormwater management was solely concerned with managing the quantity and quality of stormwater runoff in order to prevent flooding and water pollution.
• A new sustainable approach: The new perspective of urban agriculture integrates the principles of sustainability and circular economy. In this approach, urban agriculture is not just food production, it also considers the wider environmental context and resource management. By aligning with the principles of the circular economy, which emphasizes waste reduction and resource reuse, urban agriculture can play a key role in sustainable urban development.

These two terms should not be seen as separate issues, but the connection between food production and water management should be recognized. For example, green infrastructure such as rain gardens or green roofs not only help in stormwater management, but also provide space for the development of urban agriculture. Below is an overview of only some of the systems in the field of agriculture that are guided by the principles of the circular economy in stormwater management.

Rainwater harvesting

Using rainwater for agricultural purposes is a practical and financially profitable choice, especially for large roof areas on farms and significant agricultural water needs. On farms, rainwater can serve multiple purposes, including providing drinking water for livestock, but also for washing machines and yards. Greenhouses offer excellent areas for collecting rainwater for irrigation, which benefits the crops grown in them. Many crops and livestock prefer rainwater in comparison with the chlorinated water from the watersupply system. Rainwater, unlike water from the watersupply system, contains nitrogen, which is extremely important for the growth and development of plants, but also a slightly acidic pH value that facilitates the release of micronutrients.

These systems can be as simple as an above-ground tank that collects water to a professional rainwater harvesting system with a large underground reservoir and pumps to distribute the collected water for irrigation purposes

Green roofs

One of the interesting solutions of intensive urbanization with the application of the principles of sustainable stormwater management are "green roofs". They can be used for growing medicinal, spice and honey plants, and mint, lemon balm, sage and chives stand out as extremely suitable. This example has a whole range of benefits such as improved insulation, reduced CO2 emissions, improved air quality, noise insulation, etc.

For example, in Singapore, green roofs produce as much as approximately of 35% domestic food demand.

In addition to the already mentioned advantages, green infrastructure like this can reduce excessive stormwater runoff, which reduces the potential negative consequences of large amounts of stormwater. However, it should be borne in mind that rainwater, especially in urban areas, often carries with it certain pollutants such as suspended solids, heavy metals or compounds of nitrogen and phosphorus. Therefore, it is necessary to meet the requirements of quality drainage and waterproofing while at the same time ensuring sufficient moisture for growth and development of the plants.

Microponds

 Microponds are another common technique in agriculture used to collect surface stormwater, increase water infiltration and prevent soil erosion. Their principle is simple: small lagoons are surrounded by stone walls or earthen embankments on all sides in order to collect rainwater. This makes it possible to use rainwater for planting plants on a smaller scale, which allows better plant growth in case of a lack of moisture. The size of the pool can vary (from 10 to 100 m2) depending on the planted culture. The main limitation for the implementation of a micropond is the depth of the soil, which should be at least 1.5 meters.

The concept of a circular economy in agriculture involves designing agricultural systems that reduce waste, increase resource efficiency and promote regenerative practices, which in this way become more resilient, efficient, productive and environmentally friendly. Adopting a circular economy approach in agriculture not only reduces water consumption, but also promotes a more sustainable and prosperous future for both farmers and ecosystems.

Integrating stormwater management into agricultural practices is the key to sustainable water use. Strategies such as rainwater harvesting, green roofs, microponds and similar can help collect and use rainwater for irrigation, reducing reliance on other water sources.

Strategies such as rainwater harvesting, green roofs, micro-pools and the like can help collect and use rainwater for irrigation, reducing reliance on other water sources. The political environment plays a key role in creating an enabling environment for the adoption of circular economy principles in agriculture and stormwater management. Policies that encourage sustainable agricultural practices, such as subsidies or tax credits for implementing stormwater management infrastructure, can encourage farmers to adopt more environmentally friendly approaches. Furthermore, regulations that advocate water conservation and pollution prevention can ensure that agricultural activities minimize their impact on water resources.

Agricultural businesses can support circular economy initiatives by procuring the sustainably grown products, investing in research and development of innovative agricultural technologies and collaborating with farmers to implement resource efficiency best practices.

Researchers can contribute to the progress of sustainable agriculture and stormwater management through scientific studies and technological innovations. Academic institutions can offer education and training programs to equip future generations of farmers and professionals with the skills needed to promote sustainability in agriculture.

Non-governmental organisations can advocate policies for sustainable agriculture and stormwater management, raise awareness of the importance of conserving water resources and provide support and resources to farmers interested in transitioning to more sustainable practices.

By jointly accepting the principles of the circular economy and working together in different sectors, everyone can contribute to a more resilient, efficient and environmentally friendly agricultural system that benefits both farmers and ecosystems.