What Causes Flooding

[lastlid]

What causes flooding?

Many reasons have been given: improper drainage, improper garbage disposal, wrong (or no) land use planning, ongoing rapid climate change, etc. Those are all correct. But the bottom line of why there is flooding is really quite simple: Excess waters have nowhere to go.

Every problem contains within itself the seed of its own solution. 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. And then we complain that there is water in the form of floods. Sino ang tanga dyan? Ang tubig o ang tao?

Words of a knowledgeable Filipino

[Ako Si Jamie]

What causes flooding?

Rain

[lastlid]

Rain

Of course....

[lastlid]

Philippine floods a man-made disaster: experts


MANILA — "Deadly floods that have swamped nearly all of the Philippine capital are less a natural disaster and more the result of poor planning, lax enforcement and political self-interest, experts say.
Damaged watersheds, massive squatter colonies living in danger zones and the neglect of drainage systems are some of the factors that have made the chaotic city of 15 million people much more vulnerable to enormous floods.
Urban planner Nathaniel Einseidel said the Philippines had enough technical know-how and could find the necessary financing to solve the problem, but there was no vision or political will.
"It's a lack of appreciation for the benefits of long-term plans. It's a vicious cycle when the planning, the policies and enforcement are not very well synchronised," said Einseidel, who was Manila's planning chief from 1979-89.
"I haven't heard of a local government, a town or city that has a comprehensive drainage masterplan.""


http://www.google.com/hostednews/afp...fbdf4f9eb49.c1

[tanga]

As far as Philippines is concerned and especially Manila there are a number of factors to be taken into consideration as regards recent events
The rainfall was equivalent to more than a months average in less than 48 hours and followed on from TS Gener
The Mesa dam was at spill level and water was purposely released,SOP when at critical levels
Poor investment in infrastructure over many years
Informal settlers building at and over floodways and rivers
The ensuing garbage,plastics which are disposed of in canals and floodways
A lack of environmental impact studies resulting in many years of construction in unsuitable locations.
The failure to implement a dredging project in Laguna lake
The failure of a major flood pump in Taguig contributed to the crisis recently(ran out of diesel)
There are many reasons which contribute to the flooding. With the changing weather patterns it would seem that flooding is inevitable to a certain extent but this could certainly be mitigated with effective infrastructure projects. This requires funding but more importantly a degree of political will.

[lastlid]

This requires funding but more importantly a degree of political will.

Certainly the author of the content of the initial post agrees with that. But i think what he is also saying is that it need not be expensive. See below....

Rainwater Catchment Ponds: Costs and Benefits

"A small demonstration rainwater catchment pond in a village south of Manila

"The picture below 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:
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.
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).
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.
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.
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.
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.
Bigger ponds and mini-lakes also provide a place for inexpensive recreation (fishing, boating, even swimming). Of course, a ready source of food.
These reservoirs will provide a source of water during the dry season.
Oh, by the way, it will also prevent flooding.""