Building a Hydroponics System on a River [Is It Possible?]

Hydroponics systems can be made with every possible combination of materials and techniques – the only limitation is the engineering skill of the gardener. Despite saying this, can a hydroponics system be made on a river on or near a river?

A hydroponics system on a river or natural body of water is possible. There have been ancient and modern applications of this concept. However, the main problems of such a set-up are: 1) water rights and ownership, 2) capital investment, 3) labor-intensive, 4) water quality, and 5) climate.

These floating gardens and farms are applicable to not only rivers but other bodies of water. The concept is simple and effective yet there are problem areas that must be first addressed.

Can It Be Done?

Building a hydroponics system on or near a river is possible. In fact, they can be done on almost any suitable natural body of water. However, the labor, engineering, and investment make such a system economically not sustainable.

Despite seeming like a new and foreign concept, the idea of “floating gardens” on natural bodies of water as a traditional cultivation method is already used.

Facing flooding due to global climate change, Bangladeshi farmers are now turning to traditional farming techniques based on simple hydroponic principles. These “floating gardens” use the invasive water hyacinth plant in conjunction with the growing medium as rafts where the crops will be planted and raised. This is similar to the floating raft method some hydroponics or aquaponics farms use except that this is used on natural bodies of water and with organic material.

Additionally, the floating gardens are augmented with fisheries to feed the plants. In a way, this hydroponics system in a natural body of water acts similarly to an aquaponics system because plants and animals create a symbiotic relationship – the plants filter the water while the fish provide organic nutrients.

Floating farms in Bangladesh help farmers survive floods

Hydroponic systems are over 500 years old!

An ancient example is the Aztec Chinampas. These were made due to the lack of agricultural land the ancient Aztecs faced in their capital, Tenochtitlan. The first iteration used massive rafts which were anchored in the middle of the lake. The later iterations were more complex, utilizing fences to make rectangular plots.

How To Build A River-Based Hydroponics System

Applying the example set by the Bangladeshi farmers, a river-based hydroponics system can be built with organic materials such as bamboo, mulch, and water hyacinth or similar components.

The Borgen Project enumerates the steps done by Bangladeshi farmers in making their own floating gardens:

1. Construct an 8 meter long, 2 meter wide, and 1 meter (24x6x3 ft.) deep raft. Bamboo poles will be used as support.
2. Water hyacinths are used as the base of the raft and woven into it to build thickness and buoyancy.
3. Remove the poles once the water hyacinths have been woven together.
4. Wait 7-10 days. Afterwards add more water hyacinths to the raft.
5. A layer of mulch, soil, dung, and compost measuring 25 centimeters (9 inches) deep will be added to the surface of the raft.
6. Fencing and anchoring the raft to prevent its degradation from the elements and
7. Seeds are planted in a ball of compost on the raft.

The Agricultural Innovations for Eliminating Extreme Poverty (AIEEP) Project developed a video to better disseminate this technique to the public, especially to flood-stricken areas in Bangladesh where some lands are underwater for months.

How to do Floating Vegetable Garden-step by step

This is just one way of building a floating garden. There are other variations and even ones that can be made using alternative materials or more modern ones such as plastics or styrofoam.

Modern Examples

Modern-day iterations seek to bring back to modernity traditional yet effective floating gardens. These seek to produce more yield while still being sustainable to the natural ecology.

Traditional chinampas are still being used in Mexico to provide natural, sustainable, and quality produce. A modern-day iteration of the chinampa was developed by EZ GRO but, instead of organic material, it uses modern materials for durability. These can be placed on rivers and lakes.

Though situated on a solid structure like a vessel or container, floating farms are becoming increasingly popular. Concerns over declining soil health, climate change, and food security have pushed people to lean towards floating farms as a sustainable avenue of food production. These farms not only include plants but also livestock such as cows.

5 Main Problems with River-Based Hydroponics

Hydroponics systems on rivers or other bodies of water offer unique benefits. However, there are 5 main problems in creating a hydroponics system in a river that makes such systems almost very hard to put into practice: 1) water rights and ownership, 2) capital investment, 3) labor-intensive, 4) water quality, and 5) climate.

1 – Water Rights and Ownership

In the US, the general rule is that navigable waterways are owned by the state whereas non-navigable waters can be subject to private ownership. Non-navigable waters are considered property of the landowner when the bottom is fully within the land of the landowner.

The rights and ownership over bodies of water are generally regulated by the State and the laws of the land. The rights and ownership over a body of water may introduce legal hindrances where the usual conflict is whether a person’s right to a body of water is superseded by the state.

Right to the use of water logically follows this ownership paradigm. Waters owned by the state are free for the public to use but are subject to regulations and licenses. Owners of non-navigable bodies of water are free to use the water as long as it does not injure its downstream or upstream neighbors.

Before establishing a hydroponics system it is important to assess:

1) Is the water navigable or non-navigable?

2) Who owns it?

3) Who has the right to use it?

Before planning a hydroponics system on a river, it’s important to consult a lawyer first to make sure that the legalities are first set aside.

2 – Capital Investment

Creating a hydroponics system on a river or any natural body of water requires a large amount of capital investment. This investment includes but is not limited to acquiring rights or ownership over the water, materials, and maintenance, among others.

Given that water used is on a much larger scale than in conventional hydroponics systems which use controlled amounts of water running in a system, it requires significantly more capital to build and maintain.

First buying land is costly and property with water in it or through it is often more expensive. In the US, waterfront properties are highly desirable, therefore twice as expensive compared to inland properties. The reason is that there are fewer waterfront properties which drive the price upwards.

The system will be exposed to natural conditions which will cause them to wear more quickly. More materials are needed to ensure a stable and solid construction to withstand natural conditions. Depending on where you are in the world, these materials may be scarce.

3 – Labour Intensive

Maintaining a hydroponics system on a river or on a natural body of water would be more labor intensive since the building, planting, growing, and harvesting process is done on a raft or near water.

As an example, a floating garden in Caliraya, Philippines uses water hyacinths, mulch, and bamboo to make the rafts where the plants are to be grown. Multiple people are employed with the creation process alone and it does take some time to get it operational.

Building a BIGGER floating farm (2020)

Likewise, it would be comparatively more difficult and even more dangerous to plant, grow, and harvest on these floating rafts since a person would not be working in the safety of solid ground. The creature comforts of net pots, waist-level grow trays, and indoor conditions in conventional hydroponics would not be available.

4 – Water Quality

Conventional hydroponics thrive off controlling the quality of the water. In making a hydroponics system on a river or a natural body of water, the quality of the water cannot be guaranteed or manipulated at all or with the same degree of accuracy.

Apart from being unable to adjust the water purity, pH, nutritional content, temperature (and more) needed for the plants to survive, the water might be polluted. It’s also possible that for this and other reasons there are not enough organisms living in the water to make it a nutrient-rich medium for the plant to grow.

Finally, conventional hydroponics usually has sterile conditions which will not be present in natural bodies of water. This does not give it the same level of protection against pests as an indoor hydroponics system but it is still much better compared to soil cultivation as noted in Bangladeshi floating gardens.

As a caveat, beneficial microorganisms are abundant in natural bodies of water. In conjunction with other aquatic forms of life such as fish, snails, and mollusks, among others, the water is rife with natural nutrients which will be absorbed by plants. The symbiotic ecology provides sustenance to the system.

5 – Climate

Climate plays a huge factor. Tropical climates are most conducive to hydroponics on rivers or other natural bodies of water due to the abundance of materials, water hyacinths, and biodiversity. Bodies of water in tropical climates also do not freeze over which allows an individual to grow all year round.

Colder climates may have the benefit of providing more oxygen in the water due to cooler water temperatures but these benefits become unimportant when winter rolls over, freezing the water and making it difficult for plant life to thrive.

Given that freezing water is a concern, this would directly limit the types of plants that can be grown. At best, plants that can be grown during the warmer seasons are the only ones that are viable. Bangladeshi farmers tend to grow gourds, eggplants, okra, leafy vegetables, pumpkins, and onions in their floating gardens.

The Benefit of Floating Gardens and Farms

The greatest benefit of floating gardens and farms is food security. These systems can be used in conjunction with aquaculture to provide a sustainable food source without the trapping of conventional soil cultivation.

Coastal cities and areas with limited arable land can turn to their rivers, streams, and lakes as avenues for agriculture. As with all applications of hydroponics, crop quality is the same but uses less water and is in harmony with the rhythm of nature.

Using natural bodies of water to produce food sustainably is the way to go since 80% of the world’s sustainable land is already in use. It also addresses many problems such as 1) rising water levels, 2) desertification due to soil farming, and 3) food shortages.

Finally, taking a page from the Bangladeshi and Filipinos, invasive water hyacinth plants can be culled in numbers to make the floating rafts. This will clear up rivers and canals which will be beneficial for other organic life.

Takeaways

1. Hydroponics on rivers is already a practiced technique used for hundreds of years. These floating gardens have been used by many countries, especially those stricken with seasonal flooding.
2. However, floating gardens require a fair investment in terms of capital and labour. There are also hindrances which include 1) water rights and ownership, 2) capital investment, 3) labour intensive, 4) water quality, and 5) climate.
3. Floating gardens and farms provide a sustainable avenue for cultivation. Not only does it produce food but it also addresses several ecological problems in the present.

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Sources

• “Artificial-Nest Rainwater-Harvesting with Fishery and Floating-or-Rooftop-Gardening Act as 21st Century COVID-19 Epidemic-Model: Improved Biodiversity Agriculture Socio-Economic Civil-Engineering Environmental-Sciences Technology-Communication” by Subhas Chandra Datta in Journal of Civil Engineering and Environmental Sciences
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• “How to Practice Floating Gardening?” by Haseeb Md. Irfanullah in Conference: ‘Introduction of Flood-based Livelihood Models: Floating Garden using Water Hyacinth’ organized by IUCN Vietnam
• “Legal Rights To Inland Waters and Applicable Law For Lakes, Bays and Rivers” by n/a in Stimmel, Stimmel & Roeser
• “MODERN-DAY CHINAMPAS” by Larry Johnson in EZ GRO Garden
• “The remarkable floating gardens of Bangladesh” by Kalpana Sunder in BBC
• “Water Rights” by James Chen in Investopedia
• “Why Does Waterfront Property Cost More?” by Laura Agadoni in SFGate