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Hertfordshire County Council

Why manage a pond rather than leave it untouched?

Over a long period, it’s normal for a pond to fill up with silt and plant material. It will become overgrown and eventually disappear. Occasional work on the pond stops this happening, keeping the pond for people to enjoy in the future.

When it happens, this kind of work can look quite drastic. Trees around the pond may be reduced in size, plants on the banks cut back and heavy machinery brought in to remove material from the bottom of the pond.

The immediate outcome may not look good, but things will quickly grow back. The pond and its wildlife will benefit from the work for many years.

On the other hand, without management the pond could be lost entirely. Habitat loss is a major threat to species like the great crested newt, which depends on ponds. Great crested newts also need to be able to find food and shelter around the pond, and active management is important for this too.

Do ponds need to be managed every year?

No. A pond in good health doesn’t need regular attention. The plants and animals that use it go through natural annual cycles and as long as things remain in balance, the pond can be left to itself.

Pond management can change the habitats in a pond dramatically. Doing this occasionally is no problem, but if it happens too often it can have a negative effect on things living in and around the pond.

Over time, it’s normal for a pond to fill up with silt or dead plants, or for plants growing around the edge of the pond to start to take over the whole pond. That’s when it’s time to consider some work on the pond.

Clearing shading or encroaching vegetation

Ponds with lots of sunlight are much better for wildlife. The sun warms the water – especially the shallow water – helping plants, insects and amphibians thrive.

In an ideal situation, the vast majority of a pond’s edges would be open and sunny. Reducing the size of trees and bushes which surround the pond every few years helps keep sunlight reaching the pond.

As well as trees, ponds can have lots of long vegetation around their edges. This shades the edges and can slowly encroach into the pond. Ultimately, if the pond is shallow, it will be taken over completely. Occasional clearing stops this happening.

What happens if a pond dries out?

Some ponds naturally dry out during the summer, but this isn’t necessarily a problem. Many animals, like newts and beetles, actually benefit from their pond drying out.

This is because the drying reduces the number of predators in the pond, especially fish. It also exposes muddy areas, which are a valuable habitat for insects. The best kind of pond for wildlife is one with lots of very shallow water. Naturally, this kind of pond is more likely to dry out than a deeper one.

It might be tempting to refill or deepen ponds like this if they start to dry out, but it’s best to think very carefully first whether this is the right thing to do.

Managing silt or plant debris

Ponds fill up with silt and dead plant matter over time. This is a natural process, and many creatures in the pond live in this layer of material. However it can sometimes build up excessively and have a negative effect on water quality and life in the pond.

Clearing dead vegetation occasionally is one solution, but once a pond starts to fill with silt it’s a much bigger job to clear it. It’s such a dramatic event in the life of a pond that care is required. The timing is important – working in the winter means fewer amphibians will be in the pond – and the silt should be piled away from the bank to avoid smothering special plants.

Changing the profile of the banks

Shallow margins are the best part of a pond for wildlife. A deep pond with steep banks can be greatly improved by changing its profile.

This usually involves scraping off soil next to the pond, widening the pond by creating a new shallow area along its edge. The wider and more undulating this area, the better.

Changing the shape of a pond is a big job which can have a big effect. It can be combined with other major pond works, like removing silt and introducing native plants.

Improving water quality

Excessive nutrients in a pond make it unbalanced, and less attractive to most wildlife. Signs of an overly nutrient rich pond include lots of algae, or murky dark water without any plants at all.

Nutrients reach the water in lots of ways, including in the water that feeds the pond and from leaves dropped by the trees above it. One way to improve water quality is by planting reeds where water enters the pond. These act as a biological filter, trapping nutrients before they reach the pond. Reducing overhanging trees also helps.

Controlling invasive non-native species

There are several non-native pond plants which are sold at garden centres but can quickly take over and dominate a pond, reducing the amount of good habitat for native wildlife.

They can easily reach ponds by accident, and once there they can be really difficult to remove completely. Clearing the pond may have a short term effect, but it is almost impossible to find every piece of the plant. Sometimes the only solution is to dry out the pond and start again.

Prevention is the best approach – avoid introducing plants to ponds at all, and take great care if you do choose to.

Introducing native plants

After restoration, a pond might be lacking in vegetation, either in the water or around its banks. This is an opportunity to restock with native plants which are good for wildlife and pretty too.

It’s really important to be careful when introducing plants. If the wrong species finds its way into a pond it can cause major problems, and might be impossible to remove.

Why construct a pond?

Ponds are guaranteed to attract a wide variety of wildlife quickly. Pond construction is a really easy way to make a big difference for wildlife, whether or not there are already ponds at a site.

Ponds are valuable and declining habitats which support lots of important wildlife. Creating a pond gives you the opportunity to design it with wildlife in mind. This means lots of shallow water around the edge, with a long and undulating margin where animals will be able to find cover.

You’re digging a new pond in a park – isn’t it dangerous for children?

As well as being excellent for wildlife, ponds have tremendous potential for educating children about the wildlife that can be found on their doorstep. They can attract fascinating creatures like frogs and dragonflies, and provide an easily accessible link to the wonders of the natural world.

Of course any body of water is a potential danger to children, but ponds and lakes are a common feature in parks and nature reserves around Hertfordshire. The risk is extremely low with sensible supervision, and is greatly outweighed by the potential benefits.

Why shouldn’t I feed bread to the ducks?

Feeding the ducks seems like an innocent pastime. And yet there are actually many problems associated with it, both for the ducks and the wider environment.

It has been known for a long time that eating too much bread can make ducks ill. Using more natural food like oats or corn is much better for the health of the birds. But it’s the bread that the ducks don’t eat which can be an even bigger issue.

An accumulation of rotting bread at the bottom of a pond or river can encourage algae and bacteria, attract rats and spread disease. The algae also makes the water smell bad, and can slow any flow of the water. Faeces from the unnaturally large number of ducks just add to the problem. The gathering of ducks and people in a regular place can also cause erosion, damaging the banks of the pond or river.

Feeding the ducks has been a tradition of family days out for generations, and it’s unrealistic to think it will stop soon. But there are small changes you can make even while enjoying feeding the ducks, like reducing the amount you feed, giving them more natural food and avoiding feeding in the same place every time.

Contact the Countryside Management Service

01992 588433

Countryside Management Service Office (Car Park H)
Environment Department (CHG001)
County Hall
SG13 8DN