DIY $50 Water Turbine - DIY, Portable, Powerful, and Open Source

For less than $50 you can build a low head, medium power, super low cost and low tech hydro turbine.
Can be plugged into any appropriate waterway, uses only basic off the shelf and recycled materials, and simple hand tools.
Aiming for 200 to 500 watts of power/ 5-12 kWh per day from 2 meters of drop at about 50 liters per second.