Panama is lucky to have abundant sources of natural spring water. Most rural water systems here are gravity fed from a spring meaning they capture water up on a mountain and then pipe it down to a tank at the top of the community and then it flows from there down to all of the homes. I recently spent a couple days helping a friend work on a few of these in his community. The photos below were one day of work on a small, single family spring catchment.
The general idea is that you clear away the topsoil to get to the impermeable or less permeable rock or clay layer that is causing the groundwater to leave where it does. In my current job, I find lots of spring boxes and catchments that didn't do this and now have water leaving underneath or on the sides of the concrete.
The first step is to build a small dam at the front of what will be your catchment area. This dam will have the tube going to the tank, a clean out tube at the bottom, and an overflow tube at the top. You don't want pressure from excess water building up in the catchment, forcing the water to find another place to come out of the ground.
The area is then filled in with rocks. Large rocks are placed on the bottom to leave channels for the water to freely flow toward the outlet.
Small rocks are placed on top to make a smoother surface to put the concrete "lid" on.
Concrete is dumped on top of the rocks and smoothed out; butting up to the side walls, slightly sloping down toward the front of the catchment, and avoiding any areas where water can pool on top and speed up erosion.
A small box area is made in the front where they will be able to remove a concrete lid to clean out any debris that may accumulate.