What is a Riparian Buffer Zone?

If you’re interested in ecology and environmental health, you might have come across the term riparian buffer zone.

But you might also have wondered what on earth a riparian buffer zone is! 

What is a Riparian Buffer?

Stream in a Forest with Riparian Buffer Zone
Credit: Photo by JerzyGorecki at Pixabay

The word riparian refers to the bank of a stream, river, or lake. It denotes the place where land and natural watercourses meet. A riparian buffer zone is composed of the natural vegetation that grows at the edges of streams and bodies of water. Critically important to the health of the waterway and the life it supports, these areas are popular with ecologists and threatened by human development.

Riparian buffers provide a wealth of protection to the waterways they border. They shield the sensitive ecological environment of a stream from pollutants and disturbances from industry, agriculture, and human activity.

Scientists in the 1960s began to study the practice, customary in Southern Europe, of maintaining strips of vegetation between fields and streams. They found that riparian buffers were also extremely useful in woodland environments, experimenting with using vegetated zones to safeguard salmon populations in the Pacific Northwest of North America from the harmful effects of logging.

Considered among the best protection a freshwater ecosystem has against external influences, riparian buffers are now used by ecologist and agronomists worldwide to improve water quality and preserve biodiversity.

Impact of Modern Agriculture on Our Waterways

Modern agricultural and industrial practices and modern housing developments consider their environmental implications all too infrequently. But with the advent of intensive agriculture, sweeping industry, and purpose-built housing estates, our impact on the land around us has increased significantly. And not for the better!

Early agriculture consisted of small fields bordered by hedgerows. Land was rarely cleared right up to the edges of waterways, especially as the woodland environment was considered extremely useful in its intact state.

Blackthorn Blossom
Blackthorn Blossom Photo by Capri23auto at Pixabay

Hedgerow field boundaries, with their thick vegetation and deep roots, helped to mitigate the effects of agriculture on the surrounding landscape, and as intensive machinery and chemical fertilizers hadn’t yet been invented, the negative consequences of human inference in the environment were far more easily managed.

Today though, after decades of thoughtless development, our waterways and lakes suffer from pollution, sedimentation, and a general imbalance of nutrients. Riparian buffers zones can be enormously effective in repairing the damage and conserving sensitive ecosystems.

How Do Riparian Buffer Zones Work?

Ideally, a riparian buffer zone would develop and be maintained naturally. Any clearing of the surrounding land for agriculture or development purposes would be done sensitively. But sadly, that doesn’t happen nearly as often as it should. To compensate, and implement a conservation strategy, riparian buffers are now deliberately designed and installed by developers, landowners, or municipal authorities. This allows them to work towards undoing damage already done and to prevent further destruction of the aquatic environment.

Planted or constructed riparian buffers mimic their naturally occurring counterparts and can be divided into three zones. At the water’s edge, the first zone consists of native bushes and large trees and extends at least 15 feet out in a straight, perpendicular line. This zone is left undisturbed and remains free from human interference.

Riparian Zones
Riparian Zones Image Credit: agr.gc.ca

Zone One

The tree and shrub roots help to stabilize the soil of the stream bank, preventing erosion and stopping soil from sliding into the water. The leaves of the canopy slow rainfall, further preserving soil structure, and they also offer much-needed shade. This area provides a habitat and food for bank-dwelling animals.

Zone Two

The second zone, which has a minimum width of 60 feet, is planted similarly to Zone One, but here forest management is permitted on the basis that any removed material is re-grown or re-planted.

Zone Three

The third zone of a riparian buffer is usually planted with native grasses or other plants for grazing animals. In areas at the edge of human habitation, Zone Three might be a garden or wildflower meadow. Extending at least 20 feet from the outer edge of Zone Two, it can be managed on the condition that it provides sediment filtering and achieves the uptake of nutrients.

Field of Grass and Buttercups by Kira Nash
Field of Grass and Buttercups by Kira Nash at kiakari

Both of these processes are vitally important in waterway management. Filtered sediment is slowed down such that it cannot reach and overwhelm the water course, and Zone Three’s nutrient uptake helps to stop runoff and excess nutrients — nitrogen fertilizers, for example — from polluting the water. Given the delicate balance of aquatic environments, it’s essential that they remain as pure as possible to ensure the health of the entire ecosystem, from fish to invertebrates to plants.

How Can Riparian Buffer Zones Help?

YouTube video

Riparian buffers have a number of benefits ranging from the economic to the ecological. Some of their many benefits include:

  1. Reducing erosion by securing the soil not only of stream banks, but of fields adjoining the zone and upslope areas as well
  2. Managing nutrient uptake: this occurs both through the absorption of excess nutrients and also the retention of essential nutrients that might otherwise be washed away
  3. Stabilizing water temperature through the sunlight-filtering leaves of the Zone One canopy
  4. Preventing sedimentation of stream, river, and lake beds
  5. Reducing the consequences of heavy rainfall by storing water that might otherwise contribute to flooding and erosion
  6. Maintaining groundwater by holding rainfall in the soil
  7. Providing food and habitat for woodland and watercourse wildlife and fish
  8. Preventing pollution of rivers, lakes, and streams through the trapping (or binding) of harmful elements in the soil
  9. Preventing pollution of waterways through the filtering action of vegetation

Why We Need Riparian Buffers

Our effects on the planet’s ecosystems cannot be underestimated. Biodiversity loss is accelerating at an alarming rate, with a 2019 UN report warning that one million species are threatened with extinction. Riparian buffer zones are a natural, cost-effective way to improve and protect delicate freshwater ecosystems.

Thought to be most beneficial when forested or along headwater streams, riparian zones offer us a way to cushion the environment from our activities and ensure that we cause as little harm to our surroundings as possible. (And the principle is one that can be applied anywhere, even in your own garden. Leave a little wilderness between your habitation and what’s beyond, and the planet will have a little more room to breathe.)

Next time you visit a stream or lake, notice what its edges look like. Can you see a riparian buffer or does someone need to get planting?

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