Our garden has a stream on one border of it, and I'm considering adding a pond. I'm curious if it'd be practical to pump water from the stream into the pond, and then have an overflow that fed down a small run back into the stream?

I know very little about garden ponds at the moment. I think generally with a liner pond it can be hard to get the nutrient/pH balance correct, and I wondered if feeding it from an existing stream would help or hinder?

Obviously any pump needs to have a filter on it, but it won't come close to purifying the water, so it'll certainly be different to having a pond that's filled from the tap/rainwater.

At a rough guess we'd be looking at a 3-5 cubic metre pond, and the rate of flow into it from the stream could be chosen to be anything depending on the pump used.

Maybe it's a stupid idea, in which case let me know and set me straight!


  • 2
    I suspect you may have some legal hurdles to overcome first... gov.uk/guidance/owning-a-watercourse
    – renesis
    Commented Jul 25, 2019 at 16:44
  • 1
    What @renesis said. In the UK, everything is owned by somebody (even if the "somebody" is nominally the monarch) so you can't just start pumping somebody else's water without permission. Aside from that, you need to consider what is going into the stream than you can't control, and which is going to end up in your pond - not necessarily industrial pollution, but things like agricultural fertilizer runoff etc.
    – alephzero
    Commented Jul 25, 2019 at 16:54
  • Thanks, good comments. I had done a bit of googling earlier and found someone who thought that if you were taking under 20m3 per day out of a watercourse, the EA were fine with it. And crucially, I don't feel we'd be taking any significant amount of water out of the watercourse, merely diverting it and then putting it back in. I'm being naive, aren't I :D
    – Codemonkey
    Commented Jul 25, 2019 at 23:39

3 Answers 3


Another thing to keep in mind having a pond outlet tied to a stream is if you are planning on having any non-native fish in your pond. In many locations (I'm in Iowa, USA), it can be illegal to dump non-native fish into waterways. There are many stories of huge goldfish in lakes or public ponds. To the extreme case, look up what Asian Carp have done along the Mississippi River after getting flooded out of fish farms and getting introduced to an enviromnet with no natural predators.

Having the pond outflow connected to a local stream is just a recipe for disaster. Maybe you can have a pump to bring water into your pond (depending on local regulations), but I would highly suggest NOT having any natural planned outflow.

  • 1
    Excellent point!! Not only exotic fish but exotic pond plants, weeds. This is a major deal. Glad you brought this up! There is no way this could be sanctioned. I don't think anyway!
    – stormy
    Commented Jul 28, 2019 at 8:15

I agree with Renesis and Aleph. You need to check out your zoning and the rules for sure. This will not be an inexpensive project and all you need is a guest or neighbor or jealous friend to squeal on you.

There are strict strict laws and BUFFERS on all rivers and creeks, even intermittent creeks. A buffer is a distance from the bank of the river or stream and outwards where one is NOT allowed to use any fertilizer, pesticide or any construction.

Even when the creek is on your property you do not have ANY say at all about that creek or the buffer zone. I am not saying you have theses rules. This is just what I am used to in the Pacific Northwest. Salmon runs. I've caught salmon in my hands as they worked their tails off getting up a 2' wide 2" deep intermittent swale. I put him back right away. The only dudes allowed to mess with rivers and creeks are beavers and even they are being managed, now.

Have talked with others that have creeks and streams on their properties about landscaping and most had brutal restrictions. Which is a good thing, really. There are a lot of filthy uneducated people in this country that will easily dump pesticide waste into rivers, trash.

Call your Cooperative Extension Service first. Don't give them any information about you just ask questions. They should know the rules in your area. Then call your County Buildings and Code unless you live within City limits. If you live in an HOA (Home Owner Association), check out their rules as well. Don't tell anyone your address if you can get away with it. They might need to look your property up but they should be able to get by with the AREA, the NAME of the creek. To be forearmed is to be forewarned.

Ponds are an awful lot of work. Be nice if you could use that creek's water but I think that is a huge no - no. Tap water is very toxic to fish (and humans). If your other source of water is water from your municipality, that water should be used for bathing and washing clothes, not for drinking, cooking or aquariums. Hydrofluorosilicic acid plus mercury, plus arsenic, plus lead. I am not kidding. This is also called fluoride and there is not one study that shows this stuff is good for teeth and it is even worse for our brains and bones.

I am thinking you want fish? Koi? The evaporation formula for a body of water is ENORMOUS. My company constructed this humongous waterfall and pool system for some well-off people. TWO layers of pond fabric, never just one. This water fall was beautiful, not many are! We make sure there is no leak no way for water to bounce off a rock and past the fabric underneath cobble, boulders and sand. Concrete was used to secure the entire waterway.

After a couple of months the clients called us to tell us that their water bill was in the thousands!! My boss and cohorts went to find a place to go sleep. They thought as I did that there was a leak and the ONLY way to fix a water feature leak is to completely tear it out and start over. yay.

I looked up the formula for evaporation. I redid the figures over and over and had my boss and others go through the process. I've never seen big men cry all at once. The formula produced the SAME results as the extra water the client's were paying for. A BIG WHEW. (We are talking a 50 foot water fall run and 2 huge pools) with REAL 4 and 5 men boulders!

When clients have a well then I will consider ponds or a short water fall. Now mosquitoes are a big big deal carrying all kinds of NEW diseases. My favorite water feature is fairly maintenance free, gives all the SOUND of water, and when turned off there is no evaporation whatsoever. I call them Artesian Wells.

A big hole is dug in the ground with the amount of reservoir necessary. Pond liner X2, cobble, drain cobble, a 5 gallon plastic bucket for the pump, sensors for the water amount, landscape fabric on top with cobble on top of that plus Mexican River rock...When you turn on the pump the water squirts out of the cobble and splashes down on the cobble. LOOKS like water, sounds like water and is almost no maintenance. I've done these Artesian Fountains in STEREO. No fish, but unless you've raised fish in ponds you have no idea the work and worry! Raccoons, Blue Heron, Eagles, Osprey (grins), Raccoons are the absolute worst and they will find your pond and your fish no matter if you are deep in a city!

Our water from our taps is so toxic I am unbelieving people don't care. Chlorine now is different. It isn't the normal chlorine, it is chloromine in our water. chlorine versus chloromine

Penman Evaporation Formula

  • As an aside to the evaporation issue, I have pond setup which totals about 400 gallons between two ponds and a 20' stream connecting them, so lots of surface area for the volume of water. In warmer sunny and windy weather I can get evaporation enough to have to add water every day to keep the level up enough for my skimmer to work effectively. I don't keep track of how much I add (just turn on the hose until it's full again), but wouldn't be surprised if it's 20 plus gallons or so (so ~5% evaporation in a day).
    – Milwrdfan
    Commented Jul 26, 2019 at 16:28
  • Look up that formula for evaporation... Evaporation is HUGE Do you have a 'well'? I hope? I stopped doing open water features and went to simple little geysers and bubbling pots...spent the money on great lighting in the landscapes. This new chlorine or rather chloramine is toxic for aquariums, watering plants and for animals to drink (meaning us humans, pets and livestock). You need a sensor that when the water level gets to a certain point that sensor turns on the water and when the level is correct a sensor turns the hose off. You need recirculating pumps to keep the water moving...
    – stormy
    Commented Jul 28, 2019 at 8:13

I have a pond about the size ( 1000 gal) you describe. No problem at all to maintain pH,etc ; can't even remember when I last checked. I have a 30 ft long stream , 2 ft wide and 2 in. deep of recycled water. Parameters are good because the danios keep breeding in it , Koi, swordtails, mollies , etc have bred in it. Uncountable numbers of tree frogs, bull frogs, toads ,etc, have layed eggs in it I have several gallons an hour of city water running into it constantly ; evaporation and leaks. My cost has been very low; hand dug ,rubber liner over used carpet backing. HOWEVER ; tropical fish have been a lifelong hobby and I have always wanted a pond. It is a good idea if you plan to spend some hours taking care of it each week ; It would not be a good idea if you plan to look out the window at it on occasion.

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