Infiltration pools can help alleviate floods, drought<\/p>\n
David Solaiman, Lecturer, Civil Engineering, Universitas
\nPelita Harapan, Tangerang, Banten<\/p>\n
There is still hope for the alleviation of the floods that
\nusually occur at this time of year. However, despite this, people
\ncontinue to be subjected to stress as they are told to prepare
\nfor another traumatic disaster.<\/p>\n
The river desilting work currently being carried out by the
\ngovernment is good, but it represents a passive approach toward
\nflood alleviation. What is really needed now is action that is
\naggressive in nature; as in football, attack is the best method
\nof defense. Something must be done in the catchment areas in the
\nupstream reaches of the 13 rivers that caused severe inundations
\nin Jakarta early last year.<\/p>\n
At any time, rainfall causes run-off. The Ciliwung river is
\nthe biggest and has the largest catchment area among the 13
\nrivers flowing through Jakarta. The West Flood Canal was not able
\nto accommodate the excess flow from the Ciliwung and its banks
\noverflowed at several locations.<\/p>\n
Population growth in Jakarta, estimated at an annual 2
\npercent, entails the need for new residential areas. And,
\nunfortunately, these are mostly constructed in the catchment area
\nof the Ciliwung and the other rivers, which in turn increases the
\nrun-off of rainwater into the rivers because the residential
\nareas are no longer available for the infiltration of rainwater.<\/p>\n
If the same intensity of rain were to fall again this year,
\nthe discharge from the Ciliwung would be even greater than last
\nyear because of changes in land use.<\/p>\n
In 1996, the Ciliwung produced its biggest flow so far
\nrecorded at 743 cubic meters per second, a flow that has a return
\nperiod of 100 years. Between 1981 and 1985, the greatest
\ndischarge was never more than 275 cubic meters per second, but
\nafter 1985 the discharge kept on increasing in the direction of
\n400 cubic meters per second.<\/p>\n
A security system is needed to deal with the issue, otherwise
\nthere will be a never-ending flood problem in Jakarta. Attention
\nhas to be paid to catchment dynamics in terms of development
\nplans for residential and industrial areas. Human needs and
\ndesires cannot be met without manipulation of the water cycle and
\nthe landscape.<\/p>\n
Development must be based on environmental consciousness, as
\nsolving the flood problem is no simple matter.<\/p>\n
In the development of new commercial and residential areas,
\nthe increase in run-off must be controlled by providing
\ninfiltration pools and wells or pits.<\/p>\n
By providing such tools, run-off will certainly be reduced to
\nan extent that will depend on the volumetric capacity of the
\npools and pits.<\/p>\n
This is what is meant by an attacking football strategy. These
\nmeasures will not only alleviate flooding but will also increase
\nthe ground water available, which will be of crucial importance
\nin alleviating drought during the dry season.<\/p>\n
The pools and wells should be built by the householders or the
\nreal-estate developers themselves. So this idea is really like
\ntaking small steps with a view to achieving big results, and
\ntherefore needs social participation, acceptance and the
\nunderstanding of political decision-makers.<\/p>\n
It would be really worthwhile to try and implement this idea,
\npreferably in the catchment area of the Ciliwung river throughout
\nthe entire Puncak and Bogor areas. If 40,000 house compounds were
\neach provided with a pool with an average capacity of 10 cubic
\nmeters, then 400,000 cubic meters of rainwater would be retained.<\/p>\n
And if the duration of rainfall averaged one hour, this would
\nreduce the river discharge by 111 cubic meters per second, quite
\na significant amount in preventing rivers from overflowing their
\nbanks. The water collected in the pools and pits would infiltrate
\ninto the soil and increase groundwater capacity, which would
\nemerge several months later in the downstream reaches of the
\nrivers and in domestic wells.<\/p>\n
Even in Japan, people make use of tennis courts as retention
\npools by enclosing them with brick walls of up to 30 centimeters
\nin height. When the time of flooding is over, the pools are
\nallowed to drain. Outdoor parking lots are treated in the same
\nway. The flat concrete roofs of high-rise buildings are also used
\nas retention pools.<\/p>\n
Efforts are needed to bridge the gap between public knowledge
\nand scientific understanding. Erect billboards to show the need
\nfor infiltration pools, or place advertisements in the media to
\nurge people dig such pools!<\/p>\n
Since infiltration pools will have to be dug independently by
\nindividual householders. This work could, however, be carried out
\nsimultaneously, so that thousands of pools would be completed in
\nnot more than two weeks.<\/p>\n
The infiltration pools and pits would certainly truncate the
\npeak flows of our river whenever rain falls, so let us dig them
\nnow!<\/p>",
"url": "https:\/\/jawawa.id\/newsitem\/infiltration-pools-can-help-alleviate-floods-drought-1447893297",
"image": ""
},
"sponsor": "Okusi Associates",
"sponsor_url": "https:\/\/okusiassociates.com"
}