Building a moat

I am gathering info about cultivating a moat/stream around 20 acres of land in Washington state and doing it as natural but efficient as possible. My hope is to farm fish there, use it for water power and make it possible to swim/play in some areas. What are some important factors to consider? What are some natural systems you can recommend using? What are some cost effective ways? What is a realistic timeframe? I welcome all ideas and experiences. Thank you!

found some good sounding instructions for this here:

https://gizmodo.com/how-to-build-a-moat-to-keep-out-the-mongol-horde-and-y-1576553570

be sure to share pictures of this adventure with us.

That article is amusing... but not meant for serious reading imo!


By far biggest worry for me would be the departments of sadness.

In my neck of the woods, I think that to avoid them it would need to NEVER be connected to fish bearing creeks, even in winter flood.

Stocking it with anything is another point that they involve themselves with... either to license or ban depending on the species.

Using the water it contains for any commercial purpose, ie a farm that sells anything, is another.

Dams are another, engineering and permits to make aure you don't build a shitty dam that washes away an elementary school when it fails...


If you are live somewhere where the cannibal hordes have consumed the office-weasels, things get simpler..


Retention is a big concern. I have clay, but it isnt bottomless, and isnt a very predictable thickness, so the larger the work the greater the risk of delving too greedily and too deep, and losing water retention as I bust through into sand or some such. More numerous smaller ponds seem safer from this perpective..

On the other hand for storage purposes a deeper pond is preferable for temp control, evap, space required, etc... going deeper becomes a calculated gamble..

Finally, it's not that hard, if you have an excavator, to dig a lot of holes/trenches. What is hard is disposing of all the stuff you dig up! For me to dig a 14ft deep pond from ground level I end up with lots more space occupied by spoil than by pond, and taking it anywhere at all will take much more time than digging it did. And in the summer that pond will only have maybe 5ft of water in it, so going shallower isn't much of an option..


All that said... a really good contour map would be a good place to start your planning, and more info would surely spark further discussion!

bernetta putnam wrote:found some good sounding instructions for this here:

https://gizmodo.com/how-to-build-a-moat-to-keep-out-the-mongol-horde-and-y-1576553570

be sure to share pictures of this adventure with us.

thank you...I also found this article and read a bit of it. 😊👍

Dillon Nichols wrote:That article is amusing... but not meant for serious reading imo!


By far biggest worry for me would be the departments of sadness.

In my neck of the woods, I think that to avoid them it would need to NEVER be connected to fish bearing creeks, even in winter flood.

Stocking it with anything is another point that they involve themselves with... either to license or ban depending on the species.

Using the water it contains for any commercial purpose, ie a farm that sells anything, is another.

Dams are another, engineering and permits to make aure you don't build a shitty dam that washes away an elementary school when it fails...


If you are live somewhere where the cannibal hordes have consumed the office-weasels, things get simpler..


Retention is a big concern. I have clay, but it isnt bottomless, and isnt a very predictable thickness, so the larger the work the greater the risk of delving too greedily and too deep, and losing water retention as I bust through into sand or some such. More numerous smaller ponds seem safer from this perpective..

On the other hand for storage purposes a deeper pond is preferable for temp control, evap, space required, etc... going deeper becomes a calculated gamble..

Finally, it's not that hard, if you have an excavator, to dig a lot of holes/trenches. What is hard is disposing of all the stuff you dig up! For me to dig a 14ft deep pond from ground level I end up with lots more space occupied by spoil than by pond, and taking it anywhere at all will take much more time than digging it did. And in the summer that pond will only have maybe 5ft of water in it, so going shallower isn't much of an option..


All that said... a really good contour map would be a good place to start your planning, and more info would surely spark further discussion!

Thank you! That's a lot to consider and I will keep it in mind. I am trying to wrap my mind around everything included in such a process. I will start thinking about a contour map.

BTW I dont intend to sell any of the fish directly but may cook some of the fish seasonally and sell plates. Not sure if that requires a separate license from the restaurant. I want as little gov involvement as possible but Im realizing how unrealistic that may be (SHIT!).

And by "deep enough to swim" I'm thinking 4-5 feet max. In my mind, its more like a stream with one pool section a bit deeper than the rest. Maybe if gravity is used to pull the stream down into the pool and have some system that carries the water upwards.

I realize it's one thing to have a vision of something working but another to consider what it actually takes to afford those things, which is why I'm asking for a reality check.

I've discovered that moldy water will keep stagnant water safe for fish and drinking.  Water flowing towards a pond pushes leaves and grass down and mold grows under it, "treating" the water naturally.  I discovered that the lid that was under the weight of the aquarium that was holding splashed water (the upturned lid with rim was holding splashed water under the aquarium) was moldy (but fresh smelling) and adding that moldy water in the upturned lid under the aquarium to the water in the aquarium made the bubbler or filter non-essential (and the moldy water is similar to a chemical treatment in that the bubbler stirs up dirt and now the bubbler is non-essential).  If you use moldy water as treatment, the water can be completely stagnant but good.

If you were to construct it, you could make sure no water flows into it or to control the flow so it very gently goes into the body of water, because just slight flow if it's not controlled is the source of dirty and cloudy water, and to figure out a way to add moldy water to it.  Personally, I think you'd have to cover an area of the water with plastic when adding water on top of the plastic to reduce dirt stirred up.

I'm immediately thinking about land levels. 20 acres is a large area to surround, and it is highly unlikely that you will have a level circumference to build you moat around. A series of connected pools and channels sounds better.

Have you seen the Geoff lawton video where he walks around a property he used to own in Australia. He built a series of lovely connected pools and water courses.

[EDIT: Unfortunately I can't find the video easily on youtube right now. Anyone got any clues?]

Michael Cox wrote:I'm immediately thinking about land levels. 20 acres is a large area to surround, and it is highly unlikely that you will have a level circumference to build you moat around. A series of connected pools and channels sounds better.

Have you seen the Geoff lawton video where he walks around a property he used to own in Australia. He built a series of lovely connected pools and water courses.

[EDIT: Unfortunately I can't find the video easily on youtube right now. Anyone got any clues?]

That sounds like a better description of what it is I'm thinking of trying to do. Moats seem to be just still waters anyway and I want it to be running in many places. Thanks for the insight!