Stream restoration — also called river restoration or river reclamation — helps to improve the health of a river and support biodiversity.
The goal of stream restoration is to return it to its near-natural state.
If you’re attempting to determine if stream restoration is possible, here’s what you should know.
1. What is stream restoration?
Stream restoration is work that aims to improve the environmental health of a river or stream.
This effort is intended to support biodiversity, recreation, flood management, and landscape development.
2. How do you know if a stream or river needs restoration?
If you have a stream or river on your land, how do you know if it needs restoration?
Rivers and streams in need of restoration are those that can no longer perform essential ecological and social functions.
If your stream/river CAN NOT do the following, then you know it’s time to start the restoration process.
Provide clean drinking water
Remove excessive levels of nutrients and sediments before they choke coastal zones
Support fisheries and wildlife
When you have a healthy stream or river, it enhances property values and serves as a hub for recreation.
If your river or stream cannot do all of the above, it needs to be restored.
3. What are the two main categories of stream restoration?
The two primary classifications of stream restoration are as follows:
This type of restoration relies on physical interventions in a stream to improve its conditions.
The techniques used for form-based restoration techniques include deflectors, cross-vanes, weirs, step-pools, grade-control structures, engineered log jams, bank stabilization methods, and channel-reconfiguration efforts.
Although form-based restoration shows an immediate change in a stream, the desired effects aren’t always achieved if degradation originates at a wider scale.
This category of restoration aims to restore through hydrological and geomorphological processes like sediment transport or connectivity between the stream channel and floodplain.
These actions ensure the stream’s resilience and ecological health.
When you go with this method, you are restoring lateral or longitudinal connectivity of water and sediment fluxes.
This limits interventions within a stream corridor defined by the stream’s hydrology and geomorphology.
You may not see the benefits of process-based restoration immediately.
It can take time for a stream to see changes because it depends on its dynamics.
4. How effective is stream restoration?
Stream restoration is often poorly quantified because of insufficient monitoring.
There are numerous stream restoration projects globally, but their effectiveness isn’t certain.
That said, this tactic is growing worldwide because of environmental awareness and more rigorous monitoring will likely occur as a result.
5. What are different stream restoration techniques?
The typical restoration techniques use natural materials (rocks, logs, native plants, etc.) to slow stormwater flow and restore the natural meander or curve pattern found in stable streams.
Here is a long list of different stream restoration techniques that you may see.
Live branch cuttings are layered horizontally along the stream.
Because the branches are live, the roots will take hold and new plants will sprout, preventing erosion.
This method uses heavy mesh netting made from coconut fibers to hold soil in place so plants can grow.
The mesh also helps to reduce weeds and retain water.
The coconut fibers break down over time and become part of the soil.
This technique places stones in a “C” or “V” pattern in streams.
This directs water toward the center of the stream away from the bank to reduce erosion.
Floodplains are essential to a river or stream environment.
They provide flood storage, fish refuge, and habitat diversity.
However, they often get disconnected and drained to protect residential areas from flooding and create land for agriculture or other areas for development.
To restore connectivity, flood banks can be breached or set back in carefully chosen locations and allow water to spill out onto the floodplains again.
The benefit to this reconnection is…
- An increase in the flood storage area
- Recreation of wetland habitats
- Reintroduction of wetland species
- Creation of refuge for fish during high flows
Grading and planting
Stream banks with steep walls are graded into a gentler slope.
When large rainstorms occur, the gentler slopes allow for more water to flow.
The water can also flow at a decreased pace.
Plants and vegetation roots also help to stabilize the banks and hold them in place.
Imbricated rip and rap
In this method, stones are stacked to form a wall which prevents soil from being washed away into the stream during heavy rain.
This technique is highly effective when erosion is severe or close to private property.
Rocks are placed in streams in the shape of a “j” to channel the flow of water away from eroding stream banks.
The curved tip of the “j” slows fast-flowing water and allows it to pass while also creating small pools for aquatic creatures to live in.
This technique places logs to direct the stream away from eroding stream banks.
The goal is to keep the flow in the center of the stream.
This way, the stream creates small pools in the center where aquatic creatures can live.
A catchment-based approach is a community-led approach where individuals and organizations improve freshwater environments across a whole ecosystem.
Specific catchment management groups are designated as the best to identify issues and determine restoration priorities.
This approach allows a beneficial outcome because it focuses on the river system as a whole.
Mulch and planting
The edges of stream banks are lined with plants to stabilize the soil.
Rock pack and flush cut
Use supportive rock packing to protect the trees along the stream bank.
If the trees are beyond recovery, then they can be cut down, leaving only the trunks to help hold the soil in place.
This method of stream restoration anchors tree stumps with attached roots in stream banks to slow down the flow and provide an aquatic habitat for fish, amphibians, and aquatic insects.
For the stream flow to be properly slowed, the roots must face the flow.
This technique creates an environment similar to a marshland below a storm drain outfall which allows treatment of stormwater before it reaches a stream.
It also provides a habitat for aquatic plants and animals.
A series of pools are built with rocks to mimic a staircase.
These steps are designed to slow downstream flow and may protect utilities like sewer crossings.
Stone toe protection
Large stones are placed at the base of stream banks to prevent fast runoff from destroying the bank of the stream.
Another option is to have the stream bank carved back to a gentler slope and to plant native plants to hold soil in place.
This method for stream restoration anchors wood materials like logs and tree limbs along stream banks to reduce erosion and provide fish an environment to live and reproduce.
6. Why is stream restoration important?
Streams and rivers are of vital importance to humans and the way we live.
Most towns and cities were developed near rivers purposefully as a water source.
Rivers, streams, and floodplains provide benefits to society including:
Improved human health
Biodiversity and habitat
When river and stream quality is compromised so are human health, biodiversity, and habitat.
Stream restoration projects are essential to help local communities benefit from their environments.
7. What are the benefits of stream restoration?
By restoring streams, we reap all the benefits that natural and near-natural streams provide.
Increased quality of life
Reduced risk of flooding for downstream users
Improved habitats for numerous plant and animal species
Adaption to global climate change
Degradation of environmentally harmful substances (wastewater, fertilizers, etc.)
8. What is the history?
Humans have altered streams for thousands of years; although, it has not always been done in the same way.
Initially, stream alternation occurred indirectly because of land clearance for agriculture.
In Roman Times, rivers were purposefully diverted (also called “channelized” to protect against flooding).
Later, during the Industrial Revolution, there was an increase in the alteration and drainage of freshwater environments.
This caused a significant decline in water quality and a loss of habitat and biodiversity.
In Europe, there were initial attempts to remediate rivers in the early 1900s.
These attempts were small-scale artificial alterations that helped improve habitats.
Over time, techniques began to prioritize working with natural processes to restore river functions.
9. How do humans cause damage to bodies of water?
Streams, rivers, and other bodies of water only require restoration because of humans.
Humans use these watercourses and floodplains for a variety of uses including…
Land reclamation for settlements and food production
Drinking water supply
Discharge of treated wastewater
Transport and recreation
To make these uses possible, humans are constantly modifying the way that streams and rivers typically operate.
These modifications and interventions can lead to a reduction in the stream flow, erosion, and destruction of sensitive aquatic ecosystems.
10. How much does stream restoration cost?
It can be difficult to estimate the cost of stream restoration because the price often depends on the technique.
That said, in Is Urban Stream Restoration Worth It?, the typical urban stream restoration costs are $500 to $1,200 per foot.
This can turn stream restoration into a million-dollar project (easily!).
11. What are the disadvantages of stream restoration?
While stream restoration can be highly beneficial for the environment and society as a whole, it does have its disadvantages.
Here’s what you should keep in mind if you’re considering stream restoration.
Stream restoration can be very expensive (as seen above).
Dams (a common method of stream restoration) can trap sediment and become less effective over time.
Depending on the method of stream restoration, habitats can be flooded, which can lead to rotting vegetation.
When this occurs, it will result in the release of methane, which is a greenhouse gas.
When streams are restored, it can lead to a loss of settlements, and this will displace people.
Sometimes stream restoration occurs without consulting local communities, which means they have little say in where or when they are relocated
12. How do you know if a project was successful?
If you’ve recently completed a stream restoration project, you should look for the following signs.
These can give you an indication that your efforts are working.
There are pools and riffles in the right places
Walk along the stream or river and look for the slope of the water surface.
The flat water (pool) and the steep water (riffle) should be roughly where they were constructed, meaning the pools are at the bends and the riffles are in the straight sections.
These are signs that your restoration project was successful.
There is no major bank instability
If your stream restoration project was successful, you shouldn’t see large areas of erosion on banks.
While some minor sections can be okay, keep an eye on any real wear.
There is sediment deposition in the right places
What are the “right” places?
You should see it in the floodplain and the point bars on the inside of the bends.
These are the natural areas of deposition in meandering streams and rivers.
There are no head cuts
Head cuts are abrupt vertical drops on the channel bed.
These are signs of vertical instability.
They form when bed material is eroded and not replaced.
When they occur, they cause the channel bed to lower and leave a step feature in the channel.
If you see head cuts starting, you should look for the cause and intervene immediately.
Head cuts mean less flood plain access and potential fish barriers.
It also means your channel is losing sediment.
There is healthy riparian vegetation
Look for healthy vegetation on the channel banks and floodplains.
The vegetation plays a critical role in the channel ecosystem by holding the bank together with roots, providing habitats for critters, shading the stream, keeping temperatures cool, and providing carbon and food for aquatic organisms.
There are benthic invertebrates
Simply put, benthic invertebrates are little water bugs that are near the bottom of the food chain in a creek system.
They live on or under the creek substrate and eat up the leaf litter or each other.
They are critical to the aquatic nutrient cycle and also serve as dinner for a variety of fish species.
Having these water bugs in a stream lets you know that your ecosystem is thriving.
You can also study the type of benthic invertebrates in your water if you want to make sure the water quality is good.
There are fish
Fish are a superb indication that your stream is in good health.
This means that factors like flow depth, velocity, substrate, and oxygen concentration are in balance.
Stream restoration can be an expensive undertaking, but when it’s done correctly, it benefits both the environment and the community immensely.
If a stream on your land is showing any signs of needing restoration, act now!
The sooner you address its problems, the less likely it is to grow into a million-dollar expense.
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Disclaimer: we are not lawyers, accountants, or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.