empty milk bottles are filled with soil and planted with greens. They are attached to a framework, and connected to each other by rubber tubing, which allows water to drip from the top down, into a tank at the bottom, from where it can be pumped back to the top.
Possible school experiment to show importance of wetlands/riparian zones!! This shows the importance of plants in our soil. Plants like trees and grasses help purify ground water. Without them the ground water gets polluted and harder to clean and drink.