How Does Urban Agriculture Reduce Runoff?

Imagine walking down the streets of a bustling city, lined with towering skyscrapers and buzzing with activity. Amidst this urban jungle, there exists an unexpected oasis: urban agriculture. But what exactly is urban agriculture, and how does it play a role in reducing runoff? This article delves into the fascinating world of urban agriculture and explores the ways in which it helps to mitigate the effects of runoff on our environment. So, let’s take a stroll through the city and discover the surprising benefits of this green phenomenon.

How Does Urban Agriculture Reduce Runoff?

Understanding Runoff

Definition of runoff

Runoff refers to the movement of water that occurs when the soil cannot absorb all the precipitation it receives. Instead of being absorbed into the ground, the water flows over the land, collecting various pollutants and carrying them into rivers, lakes, and other bodies of water. This runoff can have detrimental effects on the environment and water quality if left unmanaged.

Causes of runoff

Runoff is primarily caused by two factors: precipitation and land surface characteristics. Heavy rainfall or the rapid melting of snow can overwhelm the soil’s ability to absorb water, leading to excessive runoff. Additionally, land surface characteristics such as impermeable surfaces, compacted soil, and lack of vegetation further contribute to increased runoff.

Impact of runoff on the environment

Uncontrolled runoff can have several negative impacts on the environment. It can lead to increased erosion, resulting in the loss of fertile topsoil. Runoff can also carry pollutants, such as chemicals from urban areas, pesticides, fertilizers, and bacteria from animal waste. These pollutants can contaminate water bodies, harming aquatic ecosystems and, in turn, human health.

Introduction to Urban Agriculture

Definition of urban agriculture

Urban agriculture refers to the practice of growing, processing, and distributing food within urban areas. It involves the cultivation of crops and the rearing of animals for food production, often in limited space and under challenging conditions. Urban agriculture encompasses a range of practices, from community gardens and rooftop farms to aquaponics and vertical farming.

Types of urban agriculture

There are various types of urban agriculture that can be found in cities. Community gardens are communal spaces where residents come together to grow plants and vegetables collectively. Rooftop farms utilize the available space on roofs of buildings to cultivate crops. Aquaponics combines aquaculture (fish farming) and hydroponics (growing plants without soil) in a mutually beneficial system. Vertical farming involves growing crops in vertically stacked layers using controlled environments.

Benefits of urban agriculture

Urban agriculture offers several benefits for both individuals and communities. Firstly, it provides access to fresh and nutritious food in areas where it may otherwise be scarce. By growing food locally, urban agriculture reduces the need for long-distance transportation, thereby lowering carbon emissions and contributing to environmental sustainability. It also promotes community development, education, and social cohesion as people come together to cultivate and share resources.

How Does Urban Agriculture Reduce Runoff?

Effect of Urban Agriculture on Runoff

Reduced impervious surfaces

One of the significant benefits of urban agriculture in reducing runoff is the conversion of impervious surfaces into green spaces. Impervious surfaces, such as concrete and asphalt, prevent water from infiltrating into the ground, leading to increased runoff. Urban agriculture initiatives such as community gardens and rooftop farms replace these impermeable surfaces with soil and vegetation, allowing water to be absorbed and reducing runoff.

Increased infiltration

Urban agriculture practices, such as regular soil cultivation and the presence of vegetation, improve the infiltration capacity of the soil. By breaking up compacted soil and increasing its organic matter content, the soil can absorb more water, reducing the amount of runoff generated during rainfall events. This increased infiltration helps replenish groundwater resources and maintains soil moisture levels, enhancing the overall ecological health of the area.

Improved soil health

Urban agriculture plays a vital role in improving soil health, which in turn helps mitigate runoff. When urban areas lack green spaces, the soil becomes compacted and depleted of nutrients, reducing its ability to absorb water. By cultivating and enriching the soil with organic matter through practices such as composting and cover crops, urban agriculture restores soil health and promotes better drainage. Healthier soil can absorb and retain water more effectively, minimizing runoff.

Rainwater harvesting

Another way in which urban agriculture reduces runoff is through rainwater harvesting. By collecting rainwater from roofs, greenhouses, and other structures, urban farmers can store excess water for future use. This practice not only reduces the volume of runoff but also provides a sustainable water source for irrigating crops during dry periods. Rainwater harvesting helps to manage stormwater and mitigate the impact of runoff on water bodies.

Reducing Impervious Surfaces

Pervious pavement

One effective method of reducing impervious surfaces is through the use of pervious pavement. Unlike traditional concrete or asphalt, pervious pavement allows water to pass through the surface and infiltrate into the ground. This type of pavement consists of porous materials or a series of interconnected voids that allow for the absorption of water. Pervious pavement is commonly used in parking lots, sidewalks, and driveways to reduce runoff and promote groundwater recharge.

Green roofs

Green roofs are another innovative approach to reducing impervious surfaces. By covering rooftops with vegetation, green roofs transform what would be an impermeable surface into a green space capable of absorbing water. The plants and soil on green roofs capture rainfall, reducing the amount of runoff generated. Moreover, green roofs provide insulation, enhance air quality, and create habitat for wildlife, offering numerous additional benefits beyond stormwater management.

Permeable sidewalks

Permeable sidewalks, also known as porous or pervious sidewalks, are designed to allow water to infiltrate through their surface. These sidewalks are typically constructed using permeable materials, such as interlocking pavers or porous concrete. By enabling water to seep into the ground, permeable sidewalks minimize runoff and contribute to groundwater replenishment. This sustainable solution can be implemented in urban areas to reduce the impact of impervious surfaces on runoff.

How Does Urban Agriculture Reduce Runoff?

Increasing Infiltration Rates

Rain gardens

Rain gardens are designed to capture and absorb rainwater runoff from roofs, driveways, and other surfaces. These specially constructed gardens consist of shallow depressions filled with native plants, shrubs, and trees. The soil in rain gardens is amended to enhance its infiltration capacity, allowing it to absorb water efficiently. Rain gardens not only reduce runoff but also filter out pollutants, recharge groundwater, and provide habitat for pollinators and other wildlife.


Bioswales are landscape features designed to manage and treat stormwater runoff. They are typically long, shallow channels that slow down the flow of water, allowing it to infiltrate through the soil. The plants in bioswales help to filter out pollutants and absorb excess nutrients. By incorporating bioswales in urban areas, particularly along roadways and parking lots, runoff is effectively managed, reducing the pollution load that enters water bodies.

Constructed wetlands

Constructed wetlands mimic and enhance the functions of natural wetlands in managing stormwater runoff. These wetland systems are designed to collect, detain, and treat runoff before it is discharged into water bodies. The wetland plants and underlying soils help to filter out sediments, absorb nutrients, and break down pollutants. Constructed wetlands play a crucial role in urban agriculture, as they can be integrated into the landscape to reduce runoff and enhance water quality.

Improving Soil Health


Composting is a process of turning organic waste, such as food scraps and yard waste, into nutrient-rich soil amendment. By composting organic materials, urban agriculture practitioners can improve the health and fertility of the soil. The addition of compost increases the soil’s ability to retain water, reducing runoff. Furthermore, compost enhances soil structure, promotes beneficial microbial activity, and provides essential nutrients for plant growth, supporting sustainable urban agriculture practices.

Cover crops

Cover crops are plants that are grown specifically to protect and improve the soil during periods when the primary crops are not planted. These crops help reduce runoff by preventing soil erosion, enhancing soil infiltration, and increasing organic matter content. By covering the soil surface, cover crops act as a living mulch, reducing evaporation and improving water retention. Additionally, cover crops can absorb excess nutrients, preventing them from entering water bodies and contributing to pollution.

Soil erosion prevention

Soil erosion is a major concern in urban areas, where construction, stormwater runoff, and other factors can strip away valuable topsoil. Urban agriculture plays a vital role in preventing soil erosion by establishing vegetation and using erosion control practices. By protecting the soil with vegetation cover and implementing erosion control measures such as terracing and contour plowing, urban agriculture minimizes runoff and preserves the integrity of the soil, ensuring its long-term productivity.

How Does Urban Agriculture Reduce Runoff?

Effect of Urban Agriculture on Water Quality

Reduced pollutants

Urban agriculture contributes to improved water quality by reducing the amount of pollutants that enter water bodies through runoff. Through the use of sustainable practices, such as organic farming methods and reduced pesticide use, urban agriculture minimizes the presence of harmful chemicals in the environment. By reducing the reliance on synthetic fertilizers and adopting natural pest control methods, urban agriculture helps mitigate the pollution caused by runoff.

Natural filtration

One of the significant benefits of urban agriculture is its ability to provide natural filtration of water. Vegetation present in urban agriculture systems, such as community gardens and green roofs, acts as a natural filter, trapping and absorbing pollutants from runoff. As the water percolates through the soil, it undergoes natural filtration, removing contaminants and improving water quality. The incorporation of green spaces within urban areas enhances this natural filtration process, reducing the pollutant load in water bodies.

Nutrient retention

Urban agriculture practices promote nutrient retention in the soil, preventing excessive runoff of nutrients into water bodies. By using cover crops, compost, and other soil amendments, urban agriculture practitioners ensure that nutrients stay in the soil and are available to plants. This prevents nutrient-rich runoff from entering water bodies and causing eutrophication, a process that leads to excessive algal growth, oxygen depletion, and degradation of aquatic ecosystems. Urban agriculture’s focus on nutrient management plays a crucial role in maintaining water quality.

Reducing Pollutants


Phytoremediation is a method that uses plants to remove, stabilize, or degrade contaminants in the environment, including pollutants present in runoff. Certain plants have the ability to absorb and accumulate heavy metals, hydrocarbons, and other toxins from the soil and water. By planting these species in polluted areas or using them in constructed wetlands, urban agriculture can help reduce the pollutant levels in runoff, minimizing their impact on water bodies.

Biofiltration systems

Biofiltration systems, such as bioretention ponds and filter strips, utilize vegetation and microbes to filter and treat stormwater runoff. These systems are designed to capture, retain, and cleanse water as it infiltrates through the soil and passes through vegetated areas. Through the combined action of plants, soil, and microorganisms, biofiltration systems effectively remove pollutants from runoff before it reaches water bodies. Implementation of these systems in urban areas can significantly reduce the pollution load in runoff.

How Does Urban Agriculture Reduce Runoff?

Natural Filtration

Wetland systems

Wetland systems, both natural and constructed, offer natural filtration capabilities for managing runoff and improving water quality. Wetlands act as a buffer, trapping sediments and nutrients, and removing contaminants from runoff before it enters rivers, lakes, or streams. These valuable ecosystems help purify water, provide habitat for diverse plant and animal species, and support ecological balance. Protecting and restoring wetlands within urban areas contribute to the reduction of runoff and improve overall water quality.

Constructed treatment wetlands

Constructed treatment wetlands are engineered wetland systems designed specifically for stormwater management. They are constructed with specific zones that allow the water to flow through, mimicking natural wetland processes. The plants, microbes, and sediments present in treatment wetlands work together to filter out pollutants, absorb nutrients, and promote biological degradation of contaminants. These wetlands effectively reduce the pollutant load in runoff, playing a crucial role in urban agriculture’s efforts to improve water quality.


Urban agriculture offers a sustainable solution to the pressing issue of runoff in urban areas. By reducing impervious surfaces, increasing infiltration rates, improving soil health, and promoting natural filtration, urban agriculture successfully mitigates the negative impacts of runoff on the environment and water quality. Through practices such as rainwater harvesting, pervious pavement, and the implementation of bioswales and constructed wetlands, urban agriculture enhances stormwater management and helps preserve valuable water resources. Furthermore, by reducing pollutants, promoting nutrient retention, and implementing phytoremediation and biofiltration systems, urban agriculture contributes to the improvement of water quality, supporting the health and well-being of communities and ecosystems. Embracing and integrating urban agriculture into our cities can lead to more sustainable and resilient urban environments while fostering a stronger sense of community and connection with the food we consume.