Here's how to build your own miniature hydropower dam

It's time to build one in your garden.
Christopher McFadden

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If you want your own miniature hydropower plant in your back garden? Then follow this simple guide to find out how. 

diy mini dam complete
Source: Construction General/YouTube

As you can imagine, you'll need some tools and materials before you get started.

Materials and gear needed

  • Bricks
  • Clear perspex
  • Scrap metal
  • Pebbles and rocks
  • Plastic pipes and caps
  • Old large lids (large paint kettle lids or similar) 
  • Scrap wooden lengths
  • Wooden poles
  • Hot glue gun
  • Spray paints
  • Digging tools (shovel, etc)
  • Cement mix and sand to make concrete
  • Welding gear


  • Supervising puppies

With all your gear in hand, it is time to get on with this great tiny build.

Step 1: Make the main perspex water chute and dam

The first step is to take your clear perspex and cut it into lengths required to transport effluent water from the dam's reservoir to the waterwheel. With that done, affix the lengths together to make a chute. 

Leave the adhesive to dry. 

Next, find a suitable location to build the main dam, reservoir, and drainage channel(s). With that done, excavate a trench using some basic tools like a shovel, and widen one end to form the main reservoir. 

Next, grab your bricks and mix up your concrete. With that done, begin to lay courses of bricks at the choke point where the dam will be. When you reach the second course of bricks, leave a gap in the dam structure to fit the main perspex chute you built earlier.

diy hydro dam structure
Source: Construction General/YouTube

Leave a gap in the dam to fit the chute, and lay some other single bricks to act as supporting pillars for the chute downstream from the dam. Keep building up the main dam structure until it completely fills the channel of the dam as needed. 

With the main brick structure complete, you can then skim the entire structure in concrete to hide your sloppy, or not, brickwork and make it watertight. 

Once done, you can install the perspex chute into the main dam structure and supporting pillars. 

diy hydro plant chute
Source: Construction General/YouTube

Concrete the chute into place on its pillars and within the dam structure as needed. With that done, add some concrete platforms to the front and rear of the dam, and concrete in some footings for the supports for the sluice gate. 

Step 2: Make the sluice gate and waterwheel

Next, take a piece of metal sheeting and a rod of metal, and weld the two together to make a paddle-like sluice gate for the dam. 

diy hydro dam sluice
Source: Construction General/YouTube

With that done, take your plastic piping and cut a short length of it for the barrel of the waterwheel. Add a pair of suitably sized caps to either end to seal the cylinder. 

Next, cut some more lengths of plastic piping slightly shorter than the main cylinder, and cut them in half to make curved paddles. Screw these into place on the main cylinder to make the waterwheel. 

diy hydro plant paddles
Source: Construction General/YouTube

With that done, remove the caps, and secure one paint kettle lid (or similar) on either end of the waterwheel to enclose the paddles. Reattach the caps once again. 

Thread a rod through the center of the caps to form an axle for the waterwheel. 

diy hydro plant lids
Source: Construction General/YouTube

Paint the waterwheel as needed. 

Step 3: Install the waterwheel

Next, build and install a pair of piles to either side of the sluice chute to the rear of the dam, and then install the sluice gate between them as needed. 

Add a lintel to the top of the piles too. With that done, install your actuator to the main rod of the sluice gate, and secure it on the lintel as needed. 

Connect up a power supply, and test the action. Adjust as needed. 

diy hydro dam actuator
Source: Construction General/YouTube

With that done, add some decoration to the dam, like fencing. If you want to add some lighting to the dam, install it now, and run the wires down the sides of the dam towards where the waterwheel will be. 

Next, add some supporting platforms for the main axle of the waterwheel just downstream from the chute. Connect up the main axle to a pair of mini dynamos, and mount these on the plinths for the waterwheel supports.

diy hydro plant waterwheel
Source: Construction General/YouTube

With that done, make a series of small pylons, and install them as needed around the dam. Next, take your wiring and connect up the main circuits to the dynamos as needed. 

Also, run the wires, where required, along the small pylons as shown. Run and connect the wires to a control box too to turn the main circuit on and off. 

Set the main switch to on, and give the waterwheel a few test rotations to ensure it is generating a current. If so, the light should briefly light up. 

diy hydro plant lights
Source: Construction General/YouTube

If not, check and adjust wiring as needed.

With that done, flood the reservoir and then open the sluice gate to watch your wonderful creation come to life. 

If you enjoyed this project, you might enjoy making another hydroelectric dam with a slight twist?

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