INTEGRATING BIOPORI IN DRAINAGE MANAGEMENT IN CAMPUSES
Biopori is a method of replicating the natural process of rapid infiltration of storm water from the surface to greater depths. The benefits of using biopori holes include:
· increased surface water absorption
Cemented surfaces and ground compacted by humans, vehicles or even animals severely reduce infiltration and so increase runoff and, in some places, erosion and flooding. To address this, gravel is often spread on the surface or ‘crazy' or brick paving is used and land can be spiked to a depth of 5 - 10 cm.
The advantage of breaking down through the surface and any impermeable clay layer for the first meter of soil can significantly increase infiltration as long as it is not blocked by the bedrock.
Biopori may also be referred to as ‘biopori hole' or ‘biopori absorption hole'. The technique was developed by Dr Kamir R. Brata, a researcher at the Bogor Institute of Agriculture, Indonesia.
There are two basic approaches. First is simply the construction and maintenance of a hole of about 10 - 30 cm wide and 100 cm deep. The second approach is that this hole is then filled with organic material, playing a double role of infiltration and decomposition. The second approach generally necessitates a wider hole that could be dug, otherwise the holes are often bored. For the maintenance of these holes, they are usually reinforced with pipes and cover of plastic, metal or cement.
Biopori is now being widely promoted in the schools and cities in Indonesia for its multiple benefits. Two campuses in Java installed biopori holes in their grounds to help manage runoff and drainage.
The Akademi Tehnik Mesin Industri (ATMI) experienced local flooding in the past. In response to this, some paved areas in the school grounds and parking lot were removed and biopori holes were installed to help improve the ground absorption of runoff.
One of the students in ATMI initiated the biopori project. Five holes of about four meters deep and 10 centimeters wide were bored into the ground to enable water to infiltrate to greater depths. The holes make use of plastic pipes with the head exposed above the ground.
The drainage canals in the campus lead to a large canal at the back of the school. Drainage from the parking lot across the road form part of another drainage system that flows into a series of canals leading to the Pepe River of Bengawan Solo some distance away. So far, the campus did not experience flooding in the last three years.
Sanata Dharma University also integrated the biopori technique in its drainage system, channeling the runoff from the roofs and grounds during heavy rains into a centralized biopori.
It is important to maintain the open flow of the hole. There are various approaches and, depending upon the soil type and use of the area, the best option may be selected. If the soil is liable to collapse into the hole, it is important to reinforce with a pipe. If the area is open to public access, it is necessary to put an adequate cover to avoid accidents.
Below are other applications of biopori: