We will consider the three major places for interceping trash and debris in the built urban environment; at storm drains, in the storm drain lines, and at the end of the storm drain system.


There are thousands of models of storm drain grates. I have narrowed down the selection here to three types. A lockable or hinged grate could be designed, and used in existing drop inlet boxes. The new drains could flip open for easy access. Drains could be part of the design theme, adding character to the urban environment. Stone grates are elegant and usually too heavy to lift. Precast concrete drains are a more affordable option and are also too heavy to lift. Recycled plastic, polypropylene or vinylester fiberglass are affordable options which cannot be used for other functions such as bbq grills, reducing the likihood of theft. Storm drain grates keep trash out of stormdrains; however, trash must still be dealt with on the surface or it may travel with sheet flows into waterways.




This solution can be fitted with hydrocarbon filters. They would need to be inspected and emptied frequently. This could potentially create additional low skill jobs.


Filter boxes fit into existing drain courses. Again, this option would need to be inspected frequently and cleaned up. Although unsightly, an option like this (or designed specifically to retrofit existing structures) treats numerous urban runoff problems and trash is easily removed behind it with a shovel.



Drop inlet CDS units may be useful for especially difficult areas, as they are very expensive in comparison with the other storm drain interception options.


This low-tech option was designed especially for Cal-trans to retrofit existing storm drain lines on feeways in California. They can be used in vaults or at discharge points to open water, detention basins, or other BMP's. They are easy to clean and have no moving parts to break. A similar product could easily be fabricated in Panama.


This solution offers great promise for Panama, either as shown or modified. The filter screen could easily be modified to act like a giant purse which could be lifted to the surface by two workers and emptied. It is below ground, so has the additional advantage of not being seen.




This is the most expensive and thorough product. A system like this could potentially be difficult for use in Panama due to filter availabilty and need for frequent maintenance. Cost is especially prohibitive. It is included for reference, and to be an option for a critically sensitive area.





The end of the line CDS unit holds great promise for Panama. One CDS unit treats a very large acreage of developed land, making the cost more reasonable. They are installed below ground, making them ideal for heavily urbanized areas. The large holding capacity and lack of moving parts are additional benefits. The only potential drawback is the vacuum truck required for sanitary cleaning. The containment sump may be cleaned manually, but it would be more difficult.


In conclusion, there are many good options for keeping trash and debris generated in the urban landsape out of the oceans and waterways. Until habits and attitudes towards litter change, these are the best defense against harmful pollution. In my opinion, the lockable hinged grate with a design theme, drop inlet boxes, storm vault filter, and CDS units hold great promise for use in El Chorillo.