How to turn an old stream into a mini hydropower dam

If the video player is not working, you can watch the video from this alternative link.
Fancy making your own power? Then why not consider building your own simple hydropower generator in a stream? 

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

Materials and gear needed

• Wood
• Metal wire
• Plastic-card or similar
• Plastic pipes
• Superglue
• Mini dynamo
• Ball bearings
• Switches
• Basic tools (pliers, screwdriver, etc)
• Orbital sander or sandpaper
• Cement mix and sand
• Soldering kit
• Electrical wires, resistors, and soldering gear

With all your gear in hand, let’s get on with the build.

Step 1: Build the main dam

Once you’ve chosen a suitable site for your project, the first step is to get your hands dirty. Grab your shovel and excavate a trench and reservoir structure for the dam. 

You can also make use of some natural features, like a small stream, instead. With the basic earthworks complete, the next step is to begin to build the actual dam structure. 

In this case, metal wire is used to form a basic frame for the main structure of the dam. The wires are bent into prong-like shapes and then driven into the soil as needed. Once done, complete the wireframe by using more lengths of metal wire as shown in the video. 

You are aiming to build a mesh-like structure for the skeleton of the dam’s main structure. Once the frame is complete, grab some scrap metal or plastic sheets and clad the metal frame to make some shuttering ready for the cement. 

Reinforce the shuttering as needed using wooden or metal piles, etc, as required. Before adding the cement, cut two lengths of plastic piping, and puncture them through the shuttering and metal frame. 

These will form the main water outlets or sluices for the dam later. 

With that done, grab your cement mix and prepare it as required. When ready, pour the cement mix between the shuttering to encapsulate the metal frame completely. 

Gently tap the shuttering on occasion to make the cement settle and remove large gaps or air bubbles. Add more cement around the shuttering and sides of the dam as needed too to ensure the structure completely closes off the trench or stream.

Leave the cement to cure. 

Once the cement has fully cured, you can now go ahead and dismantle the shuttering. Remove any supporting piles too to expose the bare concrete dam structure. 

Step 2: Prepare the dam for the power generator

Grab some more cement and build a plinth or hard standing below the sluice pipes on the downstream side of the dam too. This will be used to mount and support the main hydropower apparatus later. 

With that done, make some small box-shaped molds from plastic, wood, or metal sheet, and stick them into the cement hard standing as shown in the video. These will form the main columns for holding the hydropower assembly in place. 

Fill the molds with cement as required, and gently tap as before to remove air gaps, etc. 

While the cement is curing, go to the reservoir side of the dam and add some plastic valves to the sluice pipes as needed. Close the valves as needed. 

If you’ve built the dam in a stream, this will stop the flow of water downstream. 

Step 3: Build the power generator

Next, take some plastic tubing, plastic sheeting, your mini dynamo, etc. Cut a length of pipe to make the main axle for the generator and mark out the positions for the blades. 

Next, take your plastic sheeting, cut a series of rectangles for the blades, and glue/screw them into place on the main axle. 

This particular setup has two sets of blades the distance between them matching the distance between the sluice pipes within the dam structure. Design your as needed to match your own dam.

With that done, make a pair of mounting points for the main axle, and complete the assembly as required. Connect the mini dynamo to the axle as required too.

With that done, transfer the entire assembly to the dam mounting plinths and secure them into place as required.

Next, if needed, modify the downstream ends of the sluice pipes with pipe elbows to ensure that any exhaust water will hit the sets of blades to ensure the water can turn the main axle. 

With that done, if not already done, wire up the dynamos to a pair of AC/DC converters, and mount all electronics somewhere on the main structure to prevent them from getting wet. 

You can also add some switches to the circuits if needed. 

Step 3: Finish the project

With the main parts of the build now complete, we can add some other details too. In this case, the power from the hydropower generator will be used to power a set of light bulbs. 

If you choose this option, jerry-rig a series of pylons to carry the power cables from the generator and drive them into the soil around the dam as needed. Build as many as you need, and install the wiring needed to the power generator and pylons. 

With that done, install any lighting and connect the lights to the main wiring circuits as needed. Next, wait for the reservoir to fill up, or fill it yourself, in preparation for testing the project. 

With that done, flick the switches, open the stopcock, and watch your project come to life!

If you enjoyed this build, you might enjoy making another hydropower project?