Sustainable development for flood-resistant Manila: Rainwater Catchment Ponds, Reservoirs, and Lakes

I would like to thank Feanne who is helping me find solutions for a sustainable development for flood resistant Manila. I just cannot accept our fate that Manila will continue to flood every year. Perhaps the new normal is heavy rainfall but it does not mean we can’t do anything to prevent or minimize floods.

One solution is creating rainwater catchment ponds, reservoirs and lakes. In fact, there is a law that every barangay should have one. The pertinent law is Republic Act No. 6716 of 1989, also known as the “Rainwater Collector and Springs Development Law” .

We should encourage our mayors to comply with the law and give them an idea on how to do it.

How do we do about it? Well , first of all, we should show them the DILG circular. Have they met with DPWH? . The DPWH is promoting rainwater harvesting for non’ domestic use. lt is also spearheading the construction of rainwater collection systems in pubtic schools as part of its climate change adaptation program.

Antonio Oposa , a multi-awarded environmental lawyer and advocate posted on his Facebook account a sustainable, feasible, and beautiful idea that can be used in both small-scale and large-scale applications. He’s already successfully implemented this idea in his School of SEA in Bantayan Island, Cebu:

The solution to flooding is really very simple: Give the excess waters a place to go. That is the function of wetlands, ponds, and lakes.

But what have we done? We have paved with concrete all available lands — including wetlands, low-lying, and flood-prone areas – and turned them into housing subdivisions and commercial centers. In other words, where there used to be water, we built our human settlements.

The Solution: Rainwater Catchment Ponds, Reservoirs, and Lakes

Government should therefore find vacant spaces, especially in low-lying areas, and excavate the land and turn it into ponds, water reservoirs, and lakes so that excess waters will have a place to go.

Rainwater Catchment Ponds: Costs and Benefits

The picture above is a 10-square meter rainwater pond that author dug in the lowest part of a small patch of land south of Manila. It is a simple illustration of how a rainwater catchment pond looks like and what the benefits are:

1. Being on the lowest portion of the land, that is where water will naturally accumulate. By digging a hole there, the excess waters will have a place to go.

2. Since the bottom of this pond is unpaved with concrete (and would normally be permeable lime or sand and stones), the excess water is absorbed back into the ground to replenish the depleted groundwater table (aquifer).

3. It only cost P1,000 pesos of labor — two people digging for two days, and this is only half a meter deep. What if more people dug for more days? Or better yet, what it heavy equipment are used for larger areas? The work will certainly be accomplished much faster.

4. To prevent it from being a breeding ground for mosquitoes, populate it with fish. Then it becomes a source of protein. Also, frogs (which eat mosquito wrigglers by the hundreds) will normally populate these ponds.

5. To prevent it from being stagnant, put water lilies and water hyacinth – Nature’s amazing water cleansing and aeration mechanism. The roots of the water hyacinth suck in the dirt from the stagnant water and release dissolved oxygen.

6. Kangkong can also be planted on the shallow portions of the pond. Other vegetables and fruits (bananas, papayas, etc.) can also be planted along the banks. There is no reason why one in five of our people should be hungry-poor.

7. Bigger ponds and mini-lakes also provide a place for inexpensive recreation (fishing, boating, even swimming). Of course, a ready source of food.

8. These reservoirs will provide a source of water during the dry season.

9. Oh, by the way, it will also prevent flooding.

Read his article : in full.

Also check out this article about his School of SEA, a place where people can learn firsthand about sustainability, and even
help out in coral reef rebuilding projects.

Check Republic Act No. 6716 of 1989, also known as the “Rainwater Collector and Springs Development Law”

Republic Act No. 6716 of 1989, also known as the "Rainwater Collector and Springs Development Law&…

Photo via Tony Oposa