Rain water collection

In the last two weeks, Metro Manila and nearby provinces experienced non-stop rain, downpour at times resulting to flooded streets, overflowing rivers, school classes cancelations, cargameddon – virtually standstill traffic almost everyday! But until a month ago, for two to three months, water taps of Metro Manila were dry for lack of water. Water was getting rationed, senate hearings conducted and ended with no solution – with reservoirs filled, the problem is forgotten – at least until next dry season.

These scenarios happen every year. With the country geographically in one of the highest rainfall areas of the world, we should be able to harness the gift of nature to our benefit. We need sound water management.

If we can collect only a small fraction of total annual rainfall, we have enough fresh water to irrigate our fields, provide more than enough for our industries and households during dry season and minimize flooding during the rainy season.

How do we accomplish this?

Every house and building should be required to install rain water collection tanks, the size proportionate to the covered area of property, say 1,000 liters for a house with roof and cemented driveway/pathway area of 300 sqm; for multilevel residential building proportionate to number of residents. The new construction of multi level buildings and malls should be required to provide underground collecting pools. The rain water is good for all washing including laundry, gardening, flushing toilets which account for majority of water usage and for bath if roof is maintained clean and initial few minutes of rainfall is bypassed to storm drain. Those who can afford may provide a pump to bring water inside the house and upper floors through the same plumbing system with proper valve to separate MWSS.

In case the tank is already full and there is a coming heavy rain per PAGASA advisory, a scheduled area by area discharge of water to the storm drain should be done to make room for coming heavy rainfall thus avoiding flash flooding of the city streets.

One can google various designs and installation of rainfall collection tanks. The cost of tank and installation could be easily recovered in 2-3 years considering the high cost of Maynilad and Manila Water. The government may help by providing soft loans for the purchase and installation of tanks. The use of interconnected 3 to 5 200-liter steel or plastic drums for residential houses may serve the purpose.

Rainwater collection tanks are the most economical means of collecting and storing fresh water in many of the country’s islands where there is little or no groundwater.

For year round irrigation to make farms productive and avoid lowland flooding during rainy season, the government should build mini dams to hold water every 5 to 10 kilometers along rivers and big streams, and in cases they reach very low water level in summertime, should dredge the area behind the dam to maintain its water holding capacity for the next rainy season.

Furthermore, the government should pursue its plan of creating a cabinet level water department to manage collection, storage and distribution of fresh water for the farms, industries and households. Water is a critical resource for our growing population.

Many countries are not endowed with rainfall like us, let us manage nature’s gift properly. – Cornelio B Reformina Jr., [email protected]