View Full Version: Metro Manila Flood Control (suggestion)

Flipzi's Cove > Government Issues > Metro Manila Flood Control (suggestion)

Pages: [1] 2

Title: Metro Manila Flood Control (suggestion)


flipzi - October 15, 2009 06:36 AM (GMT)
The Ondoy Floods will return for sure and it shall be like that over and over again.

What we can do is to mitigate the effect of the flooding or control it somehow.

First, why that heavy volume?

The reason is that the rainwaters coming down from the areas surrounding Marikina River and Laguna Bay are all being flushed out into the Manila Bay via the single, narrow and overburdened Pasig River.

user posted image

Planting trees on those mountains surrounding Metro Manila may help but it cannot stop that volume.

The proposed 40 billion pesos Pasig River/Marikina River project is not enough since the volume is really great and it would need constructing walls along the river 2 stories high.

That will surely shroud the buildings and structures along the river and will be an ugly sight to see.

The other solution is to build a second floodway to flush the contents of Laguna Bay so it can be used to decongest Pasig River and even use it longer for taking in floodwaters from the Marikina River/Pasig River systems..

The Laguna Bay is normally used to take in the floodwaters from the Marikina River. But when the Laguna gets filled, it will close its floodgates to force the floodwaters to take the Pasig River route instead.

QUOTE
Metro Manila suffered from severe flooding, and Manila City itself was particularly vulnerable. A few hours of moderately intense rainfall can inundate significant portions of the densely populated city. The worst and most destructive flood occured when the Pasig River overflows its banks during intense local rainfall.

The Mangahan Floodway Project was conceived as a practical solution to the over bank problem. The Project limits the discharge of the Pasig River in bank full stages by diverting the excess water through a man made channel to Laguna de Bay. The floodway can provide protection to the greater Manila areas from peak flows with up to 100 year recurrence interval.

http://www.ctie.co.jp/english/service/proj.../project10.html


The proposed floodway is to connect existing rivers and fortify its banks with concrete walls. Floodgates may also be needed to control water flow.

user posted image

These are the other suggestions.

user posted image

We can use the 40billion pesos allocated for the Pasig River/marikina River project to the payment of the right-of-way and relocation of the affected homes in this proposed project.

Another is pumping water into Lake Caliraya and then spilling it into the Quezon coast via the existing river system that leads to it.

user posted image

Also the use of the existing canals that leads to Manila Bay by laying out large pipes that will connect Laguna Bay to the Manila Bay. We can drain Laguna Bay with this system of canals.

user posted image

flipzi - October 21, 2009 03:45 AM (GMT)
FACTS:

The Laguna de Bay Masterplan
LLDA / DENR

http://www.llda.gov.ph/masterplan.htm

The Laguna de Bay watershed region as a natural resource is strategically situated in the midst of the country’s center of urban and industrial development. Aside from Metro Manila which lies just west of Laguna de Bay, the region straddles the whole of Laguna and Rizal provinces, parts of Batangas, Cavite and Quezon which compose the CALABARZON area. This configuration makes the region a critical resource in terms of its importance as the main source of agricultural food commodities and industrial raw materials. The lake itself as well as the other smaller lakes in the basin are important sources of livelihood for the fishery sector and serve multifarious purpose - in irrigation, transportation, energy generation and other industrial uses.

The geographic features and location of the basin within the primary growth area of the country make it susceptible to destructive human interventions which in the long-term may cause irreparable damage to its resources including the loss of valuable agricultural and forest lands to urban and industrial growth.

A strategic resource of the Region is the Laguna de Bay, the second largest body of freshwater in Southeast Asia. It has a surface area of approximately 90,000 heactares, an average depth of 2.8m, a total volume of 3.2 billion cubic meters measured at elevation 11.50 meters above the Laguna de Bay datum set at 10.0 meters below the Mean Lower Low Water (MLLW) and a shoreline of 220 kms. There are 21 tributaries that drain into the lake; 35% of freshwater that drains comes from Pagsanjan River while 15% comes from the Sta. Cruz River. The only outlet of the lake is the Napindan Channel which at its confluence with the Marikina River, forms the Pasig River. This river meanders along 24-km. long course westward through a major part of Metropolitan Manila, before finally discharging into Manila Bay.

Laguna de Bay Region boundaries include six (6) provinces, 60 municipalities of which 28 towns are lakeshore and 32 non-lakeshore towns. The actual population of the Region including Metro-Manila was approximately 8.3 Million in 1990 and is expected to rise to 12.0 Million by year 2000. The lake is the singly most important resource of the Region. At present it is a source of industrial cooling water, irrigation water, and hydroelectric power; a transport route for oil products and the lakeshore dwellers; a source of snails for duck feed; a venue for recreation and most notably a source of fish supply. Also, the lake serves as a huge sink for waste coming from domestic sources (household and service sectors); non-point sources (surface run-off from urban areas, crop lans and forest lands); industries, livestock and poultry production, fishery activities and Pasig River and Manggahan Floodway inflow. The latter is most alarming since its pollution and sediment load will jeopardize the existing and potential uses of the water body.

LOCATION

Today, Laguna de Bay cover almost one half of the 190,000 ha. total area of all existing lakes in this country. It is known as the second largest inland body of water in Southeast Asia next to Lake Toba in Indonesia (Santos-Borja, 1994). It has a total surface area of about 90,000 has. and an average depth of 2.8 m. Laguna de Bay stands unique in the sense that it is right in the middle of its upper watershed. It lies just east and generally south of Metropolitan Manila. The lake has a total volume of 3.2 billion cubic meters with a shoreline of 220 km. There are 21 tributaries that drain into the lake; 35% of freshwater that drain comes from Pagsanjan River while 15% comes from Sta. Cruz River. The only outlet of the lake is the Napindan Channel which at its confluence with the Marikina river, forms the Pasig river, which meanders along a 24 km. long course westward through a major part of Metropolitan Manila, before eventually discharging into Manila Bay (Francisco, 1985). Other lakes in the region also include the Seven Crater Lakes in San Pablo City with a total surface area of 289.6 has. and Tadlak Lake in Los Baños with only 22.6 ha. area.

Laguna de Bay Region occupies 1.3% of the total land area of the Philippines. It encompasses the whole provinces of Rizal and Laguna, the cities of San Pablo, Pasay, Caloocan, Quezon, Manila and Tagaytay, the towns of Tanauan, Sto. Tomas and Malvar in Batangas, the towns of Silang and Carmona in Cavite; Lucban in Quezon province and Marikina, Pasig, Taguig, Muntinlupa and Pateros in Metro Manila. To sum it up, Laguna de Bay Region boundaries include 6 provinces, 60 municipalities of which 28 towns are lakeshore covering 177 barangays and 32 non-lakeshore towns.

Laguna de Bay is trilobate lake with three corporate bays: The West Bay, Central Bay and East Bay that converge towards the South carving out what resembles a large bird or dinosaur. The West and Central Bays are separated by Talim Island, the largest and most populated of the nine islands within the lake. It is bordered by the ruggedly high Sierra Madre mountain ranges on the Northeastern portion, the high Caliraya volcanic plateau in the East and the chains of mountains of Laguna and Batangas province to the South and Southeast, which includes Mt. Banahaw and Mt. Makiling.


HYDROLOGY OF THE LAKE

The hydrology of the lake has a natural stage regime which in the dry season results in a minimum lake elevation of about 10.5 m. controlled by mean level in Manila Bay. At the end of the dry season, the lake level may drop below the level of high tide in Manila Bay, resulting in the intrusion of seawater up the Pasig river. With this diurnal reversal, the highly polluted waters of the Pasig river system are carried in the lake. The tidal influx is also the primary cause of elevated salinity in the lake during this part of the year (Francisco, 1985).

During the wet season, precipitation results in an annual mean high water elevation of 12.5m. and a peak elevation which may reach as high as 14.6m for a 100 year recurrence interval. During extremely wet years, widespread flood damage occurs along the lakeshores because the land is relatively flat for several kilometers inland in most areas. Also during this period, the Marikina river floods the Pasig river and overflows into the Laguna de Bay via the Napindan Channel because the Marikina river can generate floodflows of about 200 m3s to 4000 m3s, and because the Pasig river bank full channel capacity varies from as little as 50 m3 to only about 750 m3s. Depending upon the tide and local inflow, the Marikina river causes flooding in and around Metropolitan Manila.


Laguna De Bay
http://en.wikipedia.org/wiki/Laguna_de_Bay

Lake Caliraya
http://en.wikipedia.org/wiki/Lake_Caliraya

Pagsanjan River
http://en.wikipedia.org/wiki/Pagsanjan_River

Sta Cruz River
http://en.wikipedia.org/wiki/Sta._Cruz_River

flipzi - October 21, 2009 03:47 AM (GMT)
Suggested PASIG RIVER IMPROVEMENT PROJECT

user posted image

This photo shows the chokepoint which slows down the water flow. This incident somehow decreases the volume of water that the Pasig River can flush into Manila Bay.

Instead of safely flushing around 1000 cubic meters of water, the water is suppressed and this would result to waters breaching the banks and forcing its way into the communities, as shown by the illustration below.

user posted image

The solution is to remove that choke point and maintain the speed of Pasig River at 1000 cubic meters per second.

Somehow, this will help Pasig River flush out the floodwaters more easily into the Manila Bay or at least speed up the draining floodwaters that have already breached the banks.

See photo below;

user posted image

Another is improving the capacity of the channels (like in the Marikina Riverbanks/SM Marikina/Industrial Valley area) by concreting it like in the Manggahan Floodway and raising its holding capacity by building a higher wall along the banks as well.

flipzi - October 21, 2009 03:48 AM (GMT)
QUOTE
From: kit canillas <fxcanillas@gmail.com>
Subject: Re: [CebuPolitics] Proposed Solution to Metro Manila Floods: 2nd Floodway is needed to decongest Pasig River
Date: Thursday, October 8, 2009, 10:20 AM


Hi Alfred,

If not mistaken, there were two twelve feet in diameter pipes that were laid in the past that went through Soldiers Hills in Putatan, Muntinlupa City and not sure if across Ayala Alabang and on to Bacoor that was suppose to assist in draining Laguna de Bay.

Would you know what became of these constructed drain pipes?  Perhaps the government already has the necessary right of way for constructing a viaduct to Manila Bay.

Kit

QUOTE

From: kit canillas <fxcanillas@gmail.com>
Subject: Erratum - Re: Proposed Solution to Metro Manila Floods: 2nd Floodway is needed to decongest Pasig River
Date: Friday, October 9, 2009, 10:58 AM


Missed to type in the word not in mentioning the temperature require to convert plastics back to oil.. It should read, "the temperature required but it was NOT a high one..."

Forgot to mention also that sludge can be made with minimal toxic heavy metals contamination by stricter garbage segregation with mixed garbage questionable in it possible use as organic fertilzer. 

The system of zero waste management can be refined that segregation will allow most organic materials processed to make organic fertilizer and garbage not suitable for such be made as landfill for reclamation.

We would not need to import chemical fertilizers and pesticides by going organic... that of course, the money making companies involved here would probably fight these moves to the teeth.



On Thu, Oct 8, 2009 at 6:42 PM, kit canillas <fxcanillas@gmail.com> wrote:

Uncanny Alfred but I just heard news yesterday about the project with the twelve-foot high pipes was junked.

Considering the size of the lake, using pumps would be quite costly to operate.  An idea occurred that what can be done is to use nature's forces to level off the water to sea level. This can be done by constructing an underground siphon tunnel leading to Manila bay.  This way the waters of Laguna lake will level off to a bit higher than the highest sea level to prevent the saline water getting into the natural aquifers fed by Laguna de Bay, as well as the bay itself.

Remembered the film clip that was shown on discovery channel on how they constructed the tunnel connecting Great Britain and France.  The size of that tunnel can perhaps actually be enough to maintain  the bay's level to its normal state thus saving billions in relocating all those whose homes and business establishments chronically inundated. 

Such tunnel siphoning would  minimize operations cost for the system since water's intrinsic characteristic of seeking its own level is used to make the system work.

Perhaps a similar tunnel can be made instead of above ground flood ways so that water run offs can pass underground than above ground flash floods thus save the Marikina and Cainta from the cataclysmic created by such flash floods and lessen the cost of the government buying extremely unaffordable rights of way.

Not sure though on how much it would cost in constructing or even if it is technically possible without altering the aquifers along the tunnel's way.

All these though we can say are band aid solutions, as the cause of such not-ever-heard-of-before heavy downpours, as the BBC docu on 'Global Dimming' presented are the suspended carbon particles from man-caused air pollution that narrows the rain-belt width around the globe that droughts are more severe in the extreme ends of the rain belt as the sub-Saharan desertification. and in areas off southern America's and parts of Australia.  This is the crux of the problem.

Even as the flood problem is being tackled, perhaps it is more important to solve the problem of environmental  pollution most specially of global warming emission of compounds that include those of minute carbon particles.

Seems the problem was created due to lust for money.  Certain technologies are mostly kept on the lid since it can significantly reduce the incomes of the big money making giants especially in the petroleum industries.

About two decades ago (more or less since forgotten the year), the TV program
'Tomorrow Today' presented a lot of inventions and discoveries on different production systems, alternative temperature control in buildings, and waste management.

Two most significant ones were one on converting plastics back into oil and the use of waste sludge as raw material for making fibre-boards used in constructions of buildings.

The technology actually is low tech.  Converting the plastics back into oil needed only a pressure cooker type of apparatus wherein the plastics are subjected to 600 PSI pressure and I forget the temperature required but it was a high one that I forgot... sure enough, they showed the oil pouring out of a tap somewhere at the bottom of the gadget.  This technology can actually take care of all the plastic litter ubiquitously clogging our sewer and drainage systems.

The fibre-board from the sludge of bio-digested garbage on the other hand was
practically fire proof with it still not burning when heat as high as 3,000 degrees Celsius was applied to the board for more than an hour.  This though still has to be further research on in terms of the possibility of it being a possible medical hazard in the way its is handled when used, as it may contain toxic heavy metals.  Perhaps DOST can look into this.

Recently the program went on air again on NET 25 and a significant temperature control for homes and green houses showed that a low tech system that does not need too high tech expensive gadgets can be constructed out of simple daily use items as cheese clothe GI pipes and plastic sheets.

The greenhouse in fact does not even need watering as water is collected by the
temperature control system from the transpiration of the plants that actually recycles water in quite an efficient cycle.

With all these technologies discovered and invented,  makes you wonder why they have not been disseminated to benefit humanity and lessen pollution... of course there would be less volume in sales of petroleum products and the ozone depleting refrigerants.

It's good that there are now more energy efficient and relatively inexpensive
environmentally friend alternatives in the refrigeration technology with the use of propane instead of the ozone CFC's and global warming HCFC's.  The use of propane as refrigerants also cuts energy consumption by as much as 90%.

There are also heat transfer systems that in tandem serves to heat as well as to
refrigerate though such technology is not open tech but closely guarded secrets of the US, Japan and Korea.  Mentioned this as the technology actually uses 80% less energy and food products processess  through the system even retains their natural enzymes with minimal loss of nutrients and enzymes as fresh produce.

We actually can have a zero waste arrangement system that is environment friendly with no global warming gasses emitted nor any carbon particles and it's all low tech and affordable.


Kit

QUOTE
Kit;


Nice input.

The tunnel is possible.

As per data, and if i got it right, Laguna De Bay is at 2 meters above Manila Bay. Im not sure what's the relative elevation during high tide, nonetheless. 

What's maybe more feasible is to build a canal as wide as Mangahan Floodway in that route as illustrated by the red line in this photo.

user posted image

We can also put a gate valve or floodgate at the "Manila Bay"-end of the canal to block seawater will pulled into the canal, and in turn leads to Laguna De Bay, during high tide.

We can somehow build a dam so we only allow water from Laguna Bay to flow out and block the seawater from coming in.

The meter elevation may be too low but it will still allow water to be pulled into the Manila Bay by gravity.


Also, during heavy rains, the water level in Laguna Bay will surely increase. That will increase the speed of the flow.

With this, the effect of the dam/canal/floodgate system will not be felt during normal days but once the Laguna Bay increase during heavy rains, the system is expected to work for what it was designed for.


I am just hopeful though.

I also agree on building tunnel or laying out pipes along the NAIA's runway so we can still use the ground level for other purpose like runway extension or a tarmac or parking area.

Also, we can create a similar floodgate/dam for the rivers dumpping water into the Laguna Bay.

We can divert these instead to the river system that leads to Quezon Bay.

( There are 21 tributaries that drain into the lake;  35% of  freshwater that drains comes from Pagsanjan River while 15% comes from the Sta. Cruz River.  The only outlet of the lake is the Napindan Channel which at its confluence with the Marikina River, forms the Pasig River.  This river meanders along 24-km. long course westward through a major part of Metropolitan Manila, before finally discharging into Manila Bay.)

http://www.llda.gov.ph/masterplan.htm


As for the main cause of it all, I agree on those things.

We need to implement rules in controlling the effect of global warming.

Sad thing is, we arent the biggest contributor to this mess but the US and the other big first world countries like in EU.

So, on our side, we should focus more on what we can do to control flooding.

And join forces with anti-fossil fuel, anti-CFC advocates across the globe to compel these 1st world nations to comply. 



Best regards,

Alfred Alexander Marasigan
Manila, Philippines
getflipzi@yahoo.com

flipzi - October 21, 2009 03:49 AM (GMT)
Subject: Mga Katanungan tungkol sa: PASIG RIVER IMPROVEMENT PROJECT - suggestion

QUOTE
From: PJRM - JMCN - SGN <pmcsi.phils@gmail.com>
Subject: Mga Katanungan tungkol sa: PASIG RIVER IMPROVEMENT PROJECT - suggestion
Date: Friday, October 9, 2009, 11:55 AM


Napakagandang mga panukala sa bandang dulo ng mahabang talakayan tungkol sa naging pinakamalubhang pagbaha sa Metro Manila at mga karatig na mga lungsod at mga munisipalidad at mga barangay ng mga Lalawigan ng Rizal, Laguna at Cavite.  Dahil ata sa haba ng talakayan ay natabunan iyong mga maituturing na mga basikong mga panglunas doon tungkol sa struktura at topograpiya ng buong lugar ng mga binaha.

Pasasaan ba at pagdating sa dulo ay haharapin ang mga tanong tungkol sa magkano ba ang kailangang gastusin at ang katumbas na tanong na mayroong bang pondo para sa mga pagpipilian na mga panukala tungkol sa panglunas.  At doon magdidikdikan kung alin nga ba ang mga realistikong mga panglunas ng siguradong sigurado na maski na ano pang panukala ay paulit ulit na mangyayari ang malubhang pagbaha.

Ang mga inhenyero mismo ang magsasabi na ang pinakamadaling panglunas ay iyong hindi gaanong gagalawin ang direksyon ng kung ano ang naging pagtakbo ng daloy ng tubig simula doon sa itaas ng kabundukan na lumandas sa kapatagan patungo doon sa dagat.  Napakadali rin namang maintindihan ng maski na hindi mga inhenyero ang prinsipyo na bago galawin ang mga tabi ay unahin muna ang pailalim.  At dito pa lang ay kitang kita agad kung ano ba talaga ang pinakasimpleng naging dahilan kung bakit umapaw ang tubig sa labas doon sa matagal ng struktura ng pagdaloy ng tubig ilog.

Samakatwid ay lulutang agad na iyong paghuhukay upang ibalik sa dating lalim at lalong palalimin ang kasalukuyang daluyan ng tubig ilog ang pinakaunang dapat gawin muna.  Hindi rin dapat iwasan maski na gaano katindi ang kontrobersiya tungkol doon sa mga naging pagharang at lalong lalo na iyong mga naging pagtabon doon sa mga natural na dinadaluyan ng tubig ilog.  Hindi dapat gulohin ang usapan ng pag-giit sa punto ng "Karapatang Pang-tao" ng mga walang lupa para pagtirikan ng mga bahay.

Kapag sinimulan agad ang paghuhukay para palalimin iyong mga kasalukuyang mga dinadaluyan ng tubig ilog ay kaagad na maiibsan simula sa baba papunta sa paitaas ang pagdaloy ng tubig ilog.  Doon pa lang kung saan dapat magsimula ay makikita kaagad kung anong kapalpakan ang mga pinagagagawa doon sa mga naunang paghuhukay para lumalim muli ang mga ilog.  Dapat na ang simula ay doon sa bungangang dulo ng dagat at hindi doon sa itaas.

Siguradong mababago ang larawan ng kung ano ba talaga ang nararapat na lunas kapag ang pagsimula ng implementasyon ay galing doon sa bungangang dulo ng dagat paitaas na kabaligtaran ng ginawang basehan na magsimula doon sa itaas ng wala pang remedyo doon sa naging natural na pagdaloy ng tubig ilog, hindi lamang dekada kung hindi ay kung ilang siglo na.

Kaya ang huling tanong ay:

Ano ang magiging kaibahan kung iyong solusyon ay magsisimula doon sa dapat na pagsimulan:  iyong bungangang dulo sa dagat paitaas?




JM

==


My answer:
QUOTE
JM;


Tama ang iyong sinabi na dapat din hukayin ang Pasig River.

Hindi lang ako sigurado kung mas mabuti ba na hukayin mula sa ibaba pataas or mula sa pataas paibaba.

Kasi kung sa ibaba ka magmumula ay matatabunan lang siya uli ng nahalukay na lupa mula sa itaas kapag sinimulan mo naman na hukayin ang mas mataas na parte dahil sa daloy ng tubig.

Kaya kung ako ay sa taas ako magmumula paibaba. Pero sa kin ay ideya lang naman muna sa mababaw na pang-unawa.


Sa kabuuan ay dapat na hukayin ang Pasig River kasi kung lalaki ang tubig na kaya nitong padaluyin ay mas mabilis na maitatapon sa Manila Bay ang tubig at siguradong mas mabilis na huhupa ang baha.

Ang pagkakaalam ko ay marami din na nakalubog na malilit na barko at barge sa Pasig River.

Ang Pasig River magmula sa parte ng Guadalupe at Mandaluyong ay mapapansin mo na malapad lang pero mababaw.

Malaking bagay din ang paglalagay ng sementadong wall sa gilid ng ilog mula sa Marikina hanggang sa bukana ng Manila Bay.

Ang dahilan ay mababawasan ang dami ng tubig na matutulak papasok sa mga kabahayan sa paligid ng ilog kapag mataas na ang tubig sa ilog. 


Kung maging epektibo ang lahat ng sistema (new flooodways, floodgates, pumping stations, river bank improvement) ay maaring pati ang baha ay tuluyan na mawala na nga.


Alfred Alexander Marasigan
Manila, Philippines
getflipzi@yahoo.com

flipzi - October 21, 2009 03:50 AM (GMT)
NAVOTAS UNSCATHED BY ONDOY .... and amazingly at that!

Fellows;

I've lived once in Navotas and I stayed with my relatives. Their home was situated around 50 meters away from the Navotas River. It's always flooding at about 5 centimeters deep during high tide. With what happened to Marikina and Cainta when Ondoy strucked, I got worried about my relatives there. I thought, if Cainta was in 7 feet deep, i assumed my relatives were even in a much worse situation.

Much to my surprise, when i called my cousin, he sounded okay as if nothing happened. Indeed, he said they did not experience any flooding at all. I asked him why it was so and he said that Navotas already have this flood control project.

Maybe, the people of Manila, Mandaluyong and Quezon City as well as Valenzuela can learn from Navotas.

Read more;

QUOTE
the infrastructure including the five pumping stations, namely: Maysilo in Kalookan; Bangkulasi, Northern Navotas and Spine in Navotas; and Catmon in Malabon have been completed by Nishimatsu Construction Co Ltd.

The pumping stations have been operational since September last year after conducting the dry-run two years ago since Navotas is already flood free.

She also commended the efforts of Navotas Mayor Toby Tiangco for making sure that their local projects would complement the flood mitigation endeavor.

At present, the department is constructing the supporting structures, the polder dikes that are elevated by 12.6 meters and in 8.6 kilometers in length.

Aside from building structures, they will also conduct river improvement works, dredging, and river widening.

Flood has been a perennial problem in the northern part of Metro Manila wherein floodwaters last for several months or even years but once the project is fully operational, it would help water to quickly subside and looking to reduce from 2.5 meters in height to just ankle level.

flipzi - October 21, 2009 03:57 AM (GMT)
It's not because of the multi-billion pesos Kamanava Flood control system but the network of 24 pumping stations set up across Navotas

- Mayor Tobi Tiangco and the City Engineer
QUOTE
He said all pumping stations function well for 36 hours during the height of typhoon "Ondoy."

"Gumana lahat ang pumping stations sa loob ng 36 oras, walang nag breakdown, kaya wala kaming evacuees," Tiangco said.

He even thought of announcing the opening of classes at the elementary and high school today,  Thursday, ahead of the schedule set by the Department of Education and the Commission on Higher Education, saying that almost all areas are passable.

In the past, Navotas, used to be one of the flood-prone areas, but the problem is slowly becoming a thing of the past since the pumping stations were installed in 2002.

In past years, when we were heavily hit by floods, the water subsided within 30 minutes but now it's gone in 10 minutes, Tiangco said.

"I cannot assure that Navotas would be totally flood-free, we can only say that we are doing our best to minimize flooding,” the mayor said, adding "our target is zero-flooding.”

Tiangco also cited the proper disposal of garbage, and the clean-up of all drainage and canals as factors to the free flow of water.

We see to it that esteros are cleared because even if we have the pumping stations floods will come unless they are all cleared, the mayor said.

Engr. Virgilio Cruz, assistant city engineer said, "we don't rely on the Mega flood Control Project in order to mitigate the flooding."

Cruz, said the city government has 24 bombastic pumping stations in Bangkulasi, Sipac-Almacen, Vadeo Dos, Kahunari, Daang-Hari, Babansi, Yangco, Phase-2 Area 1, Mamale, Maliputo, Bagumbayan, Tagahanan, two units at San Rafael and six at Tanza.

They two other units are also being eyed in Barangay Tanza, he said.

http://www.mb.com.ph/articles/222635/navot...ts-zeroflooding

As for me, I believe them. Look at the photo below;

user posted image

As you can see the Mega project is situated far from the Navotas City proper where the "no flood" miracle happened. In fact, it's far from the mouth of Tullahan River, where the heavy volume comes from.

See this map;

user posted image

A second look at the multi-billion peoso mega project though, the design seems to be okay.

See this;

user posted image

The Main Pumping Station is actually a part of the whole system.

The whole area that were targetted to benefit from this project is protected by 2 gates that prevents floodwaters from other canals to flow in.

During floods, the 3 gates (in Dampalit River, Batasan River and Navotas River near C4 road) are closed to prevent floodwater from coming in and then the remaining water within the enclosed zone is pumped out into the sea by the large pumping station at the Mouth of Tangos River.

I believe this is effective (or will be effective since the project is yet to be completed)

Nonetheless, the existing pumping station is only serving the northern part of Navotas and the main part of Malabon.

The remaing southern part of Navotas is not yet protected.

Luckily, Mayor Toby Tiangco has installed his 24 "Bombastic" pumping stations across these areas.

Hopefully, when all these flood control projects are completed, Navotas will be free from floods or somewhat.

Please look back at the photo again.

The highlighted areas at the bottom are the suggested projects. This is the second mega flood control project.

The idea is to seal off Navotas River from the floodwaters coming from Tullahan River and then dumping the water from within into Manila Bay using the pumps located at the mouth of Navotas River. This is the area near the "Smokey Mountain" site.

With this, Navotas, Caloocan and Malabon (especially Navotas) will have less floods.

flipzi - October 21, 2009 04:02 AM (GMT)
Mayor Toby Tiangco's vision of Navotas;

user posted image
QUOTE
Mayor Toby Tiangco leads the Memorandum of Agreement (MOA) signing of the contract for the proposed Reclamation and Development of the Navotas Bay Area. The said program, a P60 Billion reclamation project, will add at least 160 hectares of prime space to Navotas city to spur economic activity in this coastal section of the metropolis. In 2008, Tiangco asked Palafox Associates to design the makeover of Navotas together with Woodfields Consultants, Inc. The masterplan consists of a mixed use zone of residential and commercial sections with pocket parks including a business and other leisure centers. Joining the Mayor are (seated from left) Atty. Florencio Orendain and Ms. Vicky Pacis of the First Sea Front Renew, Inc., Vice Mayor PJ Javier. Witnessing the signing are (standing from left) City Planning and Development Officer Engr. Raffy Serrano, Mr. John Rey Tiangco of the Metro Manila Shipyard Association and Coun. Boy Vicencio.

flipzi - October 21, 2009 04:04 AM (GMT)
QUOTE (saver111 @ Oct 9 2009, 03:50 PM)
So, gumagana na pala yang sa Navotas. I used to live there too. Because of those floods which continuously rising yearly, we had to move. I remember that the Dagat-dagatan project was the main reason of those floodings. It used to house fishpens which was 3 meters lower than the surrounding areas of CAMANAVA. When it was reclaimed for the housing projects, it was filled up by 5 meters making the surrounding area now 2 meters below. So when it rains, water now goes to the low areas.

Before we left, a flood control project was being emplaced with equipments coming from the Netherlands, known for such flood control technology. I think the project was overrun by events after the EDSA revolution. Just like other projects of the Marcos regime, it was abandoned with parts or the equipments cannibalized or lost.

So to the energetic Mayor,  :thumb:

BTW, annual dredging of rivers during summer is a must which should also be done in the surrounding areas of Pinatubo. Make it an annual event like a fiesta where people will work hand in hand. Prevention is always the key.

Yes, Buddy. Almost all the people, from Malabon, Caloocan and Navotas can agree to that.

Before, when the areas where still filled with fishpens, there's not much flooding in Malabon and Caloocan, as well as in Navotas. The areas seemed to have been the catch basin for the floodwaters. Now, that it is gone, the floods have nowhere to go but right into their homes.

We need to bring that back. Not by destroying the houses but by improving the river systems and putting in more pumps and floodgates.

flipzi - October 21, 2009 04:04 AM (GMT)
KAMANAVA - Tullahan River Flood Control Project

user posted image

Another unsolved case is the Tullhan River which serves as the main drainage for Quezon City (includes Fairview, Commonwealth), Novaliches, Valenzuela, Bulacan, Malabon, and even Navotas.

The suggestion here is improvement of the river banks by buidling concrete dikes.

Another is the removal of choke points. Two possible choke points are highlighted in the image above.

Then finally the widening of the mouth on Tullahan River.

Dredging the river regularly is necessary.

Quezon City has 2 important rivers that it improve and preserve. These are the Tullahan and the San Juan Rivers. The San Juan River dumps its water into the Manila Bay via the Pasig River.

user posted image

flipzi - October 21, 2009 04:06 AM (GMT)
MAIN WATERWAYS

Tullahan River: (major channel)
1. Drains water from La Mesa Dam, as well as the northern part of Quezon City, Valenzuela, Novaliches, Malabon and Navotas.
2. Mouth is at Navotas.

Marikina River: (major channel)
1. Drains water from Marikina, Cainta, Montalban, San Mateo and Antipolo as well as some parts of Quezon City.
2. It leads to Pasig River.
3. Or it leads to Laguna De Bay if the lake is still able to take in water.

Pasig River: (major channel)
1. Drains water from Laguna De Bay and Marikina River, and also QC, Makati, Mandaluyong, Manila and San Juan (including San Juan River).
2. Dumps water directly to Manila Bay

San Juan River (major channel)
1. Drains water from Quezon City (like Tandand Sora and as far as Sauyo/Fairview/, San Juan and Manila.
2. Dumps water into Pasig River

Maytunas Creek
1. Drains Mandaluyong and San Juan
2. Dumps water into San Juan River

Angat River (major channel)
1. Drains water from Angat Dam, Norzagaray and other Bulacan areas.
2. Mouth is at Hagonoy, Bulacan and dumps water directly to Manila Bay

Navotas River (major channel)
1. Drains water from Navotas, Caloocan and Manila
2. Intersects with Tullahan River at the middle
3. Dumps water directly to Manila Bay (southern end)
4. Dumps water to Tangos River (northern end)

Polo River
1. Drains water from Malabon, Valenzuela and Bulacan
2. Dumps water directly to Manila Bay

Tanza River
1. Drains water from Navotas
2. Connects with Dampalit River
3. Dumps water to Tangos River

Tangos River
1. Drains water from Navotas
2. Dumps water directly to Manila Bay

Dampalit River
1. Drains water from Malabon and Navotas
2. Dumps water to Tangos River

Batasan River
1. Drains water from Malabon and Navotas
2. Dumps water to Tanza River which leads to Manila Bay via Tangos River

Muzon River
1. Drains water from Malabon and Bulacan
2. Dumps water to Manila Bay via the entrance of Marilao River in Bulacan

Meycuayan River (major channel)
1. Drains water from Valenzuela and Meycauayan in Bulacan
2. Dumps water into Manila Bay via Marilao River

Marilao River (major channel)
1. Drains water from Marilao, Meycuayan and as far as the nothwestern side of the La Mesa Dam area.
2. Two other rivers, the Meycuayan River and Polo River that drains Malabon and Valenzuela dump their water here.
3. Another great rivers, the Santa Maria River and Balagtas River meet up with the Marilao River in the Obando area before reaching Manila Bay.

Estero de Maypad
1. Drains water from Manila, Navotas and Caloocan
2. Dumps water to Navotas River

Estero De Vitas (major channel)
1. Drains water from Manila (as far as Tayuman)
2. Dumps water directly to Manila Bay

Estero Sunog Apog
1. Drains water from Manila
2. Dumps water to Manila Bay via Estero De Vitas

Canal dela Reyna River ( major channel)
1. Drains water from Manila as far as Tayuman, Claro M. Recto, and Binondo
2. Ends in Binondo and there is a floodgate or pumping station in that end at Muelle de Binondo.
3. Dumps water into Pasig River at its southern tip.
4. Dumps water into Manila Bay via Estero De Vitas in its northern tip.

Estero Sunog Apog
1. Drains water from Manila
2. Dumps water to Manila Bay via Estero De Vitas

Estero de Paco
1. Drains Paco and Pandacan
2. Leads to Pasig River

Estero de Pandacan
1. Drains Pandacan and Paco.
2. Dumps water into Pasig River

Estero de Tripa de Gallina (major channel)
1. Drains water from Manila (Paco, San Andres), Makati as far as Fobres Park and Fort Bonifacio and then through Buendia Ave in Makati and Pasay City (including Bangkal and Don Bosco Makati) and then in Paranaque
2. Dumps water into Manila Bay via the Paranaque River at in intersection near western side of the NAIA runway.

Paranaque River (major channel)
1. Drains Paranaque, Pasay and Manila areas
2. Dumps water directly into Manila Bay

Pateros River (major channel)
1. Drains water from Makati area (Guadalupe, Fort Bonifacio) and Pateros
2. Dumps most of its water into Laguna De Bay via Laguna River at its southeastern tip.
3. Dumps some of its water into Pasig River in Guadalupe

Las Pinas River (major channel)
1. Drains water from Las Pinas
2. Dumps water into Manila Bay directly

Zapote River (major channel)
1. Drains water from Las Pinas and parts of Bacoor Cavite
2. Dumps water into Manila Bay directly
Laguna River (major channel)
1. Drains water from Makati, Pateros and Taguig
2. Dumps water into Laguna De Bay

Sucat River (major channel)
1. Drains water from Paranaque and Muntinlupa
2. Dumps water into Laguna De Bay

Pasong Diablo River
1. Drains water from Alabang
2. Dumps water into Laguna De Bay

Alabang River
1. Drains water from Alabang (up to Ayala Alabang Village and Festibal Mall)
2. Dumps water into Laguna De Bay via Pasong Diablo River

Bayanan Creek
1. Drains water from Alabang
2. Dumps water into Laguna De Bay

Poblacion River
1. Drains water from Alabang (Poblacion)
2. Dumps water into Laguna De Bay

Magdaong River
1. Drains water from Alabang
2. Dumps water into Laguna De Bay

Tunasan River
1. Drains water from Alabang
2. Dumps water into Laguna De Bay

flipzi - October 21, 2009 04:07 AM (GMT)
user posted image

QUOTE
La Mesa dam helped prevent flood, too

Espinueva said that it is possible that the La Mesa dam, which is in Quezon City, overflowed during the storm because the spilling level of the dam is only 80.15 m.

She explained that the La Mesa dam receives water from the Angat dam, passing through Ipo dam’s underground tunnel to fill its reservoir with Metro Manila’s water supply.

“It has no gate, the dam has no spilling or pre-spilling operations,” she said. Instead of spilling, the dam’s water level is lowered because the water goes to the faucets of residents of the Metro, she said.

Espinueva said heavy rains could have caused water from La Mesa dam to overflow. She maintained, however, that even this couldn’t have been the reason for flooding.

“Whether La Mesa dam is located in Metro Manila or not, because of the month’s worth of rain that poured during that Saturday, there will be flooding,” Espinueva said.

She added that even the La Mesa dam also helped in preventing more floods. “The dam would be able to catch and store rainwater, instead of it going straight to streets,” she said.

QUOTE
Pre-storm spilling operations

In a note posted on botomoipatrolmo.multiply.com, Multiply user RD suggested that enough space should be left in each dam to accommodate at least 3 to 5 days of continuous rain. This way, he said, water release from the dam will not exacerbate flooding caused by heavy rains.

This is actually being done already, according to dam authorities.

As a matter of procedure, spilling operations are done before any storm hits the country, Espinueva said. These operations affect flood prone areas near the dams. These areas are called target areas.

flipzi - October 21, 2009 04:08 AM (GMT)
REFERENCE:


Raw Water Sources

The Angat-Ipo-La Mesa Dam Raw Water System is currently the major source of water for Metro Manila. The water extracted from this location is treated in two facilities: The Balara Treatment Plant (Manila Water Company, Inc.) and La Mesa Treatment Plant (Maynilad Water Services Inc.).

Angat Dam

The Angat Reservoir and Dam are located at the Angat River in San Lorenzo, Norzagaray, Bulacan. The facilities were constructed from 1964 to 1967 and have been operational since 1968. They have multiple functions:

•To provide irrigation to about 31,000 hectares of land in 20 municipalities and towns in Pampanga and Bulacan;
•To supply the domestic and industrial water requirements of residents in Metro Manila;
•To generate hydroelectric power to feed the Luzon Grid; and
•To reduce flooding to downstream towns and villages.
The principal river, Angat River, originates from the western flank of the Sierra Madre Mountains. It then cuts through the mountainous terrain in a westerly direction to the dam site. The elevation within the watershed rises to a maximum of 1,115 meters at the Sierra Madre Mountain range and is lowest at the dam site at 100 meters. It has three major tributaries, namely, the Talaguio, Catmon and Matulid Rivers. The Angat Watershed has a moderate to intensive forest cover and has a drainage area of about 568 square kilometers, which receives an average annual rainfall of about 4,200 millimeters.

The Angat Dam is a rockfill dam with a spillway equipped with three gates at a spilling level of 219 meters. Its storage capacity is about 850 million cubic meters. Water supply to the MWSS is released through five auxiliary turbines where it is diverted to the two tunnels going to the Ipo Dam.


Ipo Dam

The Ipo Dam is a gravity concrete dam located about 7.5 kilometers downstream of the Angat Dam near its confluence with the Ipo River in Bulacan. It was completed in January 1984 with a maximum storage capacity of 7.5 million cubic meters, an increase of about 2,500 million liters per day (MLD) from the old Ipo Dam, which used to be located 200 meters upstream of the new dam.

The spill level of the dam is at an elevation of 101 meters and it has seven radial floodgates. The watershed topography is characterized by mountainous terrain similar to the Angat Reservoir Watershed with moderate forest cover. The watershed has an area of about 70 square kilometers and receives an average annual rainfall of 3,500 millimeters. Tributaries to the Angat River at this section include the Ipo, Sapa Pako and Sapa Anginon Rivers. These tributaries drain into the Angat River from the eastern section of the watershed.

Water from the dam is diverted to the Novaliches Portal and the La Mesa Dam through three intake structures going down to three connecting tunnels into five connecting aqueducts.

La Mesa Dam

The La Mesa Dam is an earth dam located in Novaliches, Quezon City. It was first erected in 1929 and then further raised in 1959 to a maximum storage capacity of 50.5 million cubic meters. Overflow level of the dam is at an elevation of 80.15 meters. The watershed has an area of 27 square kilometers, which receives an average annual rainfall of 2,000 millimeters.

How water is transmitted

From the Angat Dam, water flows through two concrete diversion tunnels down to the Ipo Dam. The Ipo Dam serves as an intermediate intake and water is then conveyed through three intake structures at the dam going to three connecting tunnels. Both Tunnels 1 and 2 have a length of 6,400 meters each and have a capacity of 760 MLD and 1,890 MLD, respectively. Tunnel 3 is about 6,100 meters long and has a capacity of 2,000 MLD.

Water from the three tunnels flows to three settling basins in Bicti, Norzagaray which are connected to five Bicti-Novaliches aqueducts. With each one comprising multiple segments of pipe siphon and tunnel, Aqueduct Nos. 1, 2, 3 and 5 are all about 15 kilometers long while Aqueduct No. 4 is about 1,650 meters long. Aqueducts 1 and 2 share common tunnel segments interconnected with parallel dual pipe siphons and have a combined capacity of 380 MLD. Part of the flow at Basin 1 is diverted to Aqueduct No. 3 that has a capacity of 830 MLD. Aqueduct Nos. 4 and 5 have a capacity of 1,250 MLD and 2,000 MLD, respectively. The five aqueducts can deliver a maximum capacity of 4,500 MLD at the Novaliches Portal.

At the Novaliches Portal, most of the water is conveyed through three open channels going to La Mesa Treatment Plants 1 and 2 and the Balara Treatment Plant. The rest of the water goes directly to the La Mesa Dam. The La Mesa Dam has three intake structures, with three connecting aqueducts to the Balara Treatment Plant ranging from 7,500 and 6,700 meters long. Both Aqueduct Nos. 1 and 2 have the same capacity of 565 MLD while Aqueduct No. 3 has a capacity of 1,140 MLD.

Aqueduct No. 3 is joined by the 1,700 meter Balara Bypass that is connected at the Novaliches Portal and has the same capacity as the said aqueduct. From Aqueduct No. 3, water flows to Balara Treatment Plant No. 2 while the water from Aqueduct No. 1 goes to Balara Treatment Plant No. 1. Water from Aqueduct No. 2 is diverted either to Balara Treatment Plant No. 1 or 2. Another bypass located at the interconnecting line between the Balara Bypass and Aqueduct No. 3 is connected to Aqueduct No. 1. This bypass is operated when the La Mesa level falls below 71 meters to divert the water directly to the Balara Treatment Plant instead of to the dam to prevent further water losses at the dam due to seepage and evaporation.

At the Alat River near Novaliches, a low weir with flashboards on the ogee crest diverts stream flows through an aqueduct going to the La Mesa Dam. This aqueduct is about 2,000 meters long and has a capacity of 380 MLD.

The Treatment Process

Water Treatment in Balara consists of four processes, namely, coagulation/flocculation, sedimentation, filtration and disinfection. In the coagulation/flocculation processes, coagulants and coagulant aids are mixed uniformly with water to be treated to allow bridging or adhesion of individual particles into flocs that settle more easily. This is accomplished by a slow, extended mixing process that converts minute particles into discrete, suspended particles. Balara Treatment Plant No. 1 has 12 vertical-type, motor-driven flocculators per basin while Balara Treatment Plant No. 2 has nine flocculators per basin. Detention time is 20 minutes. Balara Treatment Plant No. 2 has 12 basins, each of which has a capacity of 120 MLD. Balara Treatment Plant No. 1, meanwhile, has two basins with a capacity of 140 MLD per basin. Determination of coagulant/coagulant aid dosage to be adopted for plant use is obtained by conducting a jar test. The flocs are then made to settle down in the sedimentation basin and this is accomplished by enlarging the area of the basin to reduce the velocity of the water and adopting a chemical dosage which has a greater settling rate than the designed overflow rate of the basin. Detention time is about two hours. After the sedimentation process, water to be treated is passed through a media consisting of several layers of graded sand and anthracite to screen out all foreign particles which did not settle down in the sedimentation basin. Detention time is around 20 minutes. The Balara Treatment Plant uses the chlorination method of disinfecting water. Chlorine is applied at three points: pre, intermediate and post-chlorination. Pre-chlorination is applied for taste and odor removal and is usually 0.3 mgl. Intermediate chlorination is for filter aid while post-chlorination is for disinfection purposes, having dosages of 0.3 and 1.2 mgl, respectively. Finally, water is then sent to distribution by gravity and by pumping.

SOURCE:

Manila Water Company

http://www.manilawater.com/section.php?sec...35&article_id=6

flipzi - October 21, 2009 04:09 AM (GMT)
REFERENCE:


LA MESA DAM

The La Mesa Dam is located in Novaliches, Quezon City, Metro Manila (MM) across the Tullahan River as shown in Figure 3.1. It is one of the two major dams whose primary purpose is water supply for the entire Metro Manila area. Construction of the dam began in 1926 and was completed on June 1929; but with the increasing demand, the Metropolitan Waterworks and Sewerage System (MWSS) decided in 1957 to increase the capacity of the reservoir by raising the dam. The project was completed in 1958. In 1991, the dam was again raised to a new elevation of 80.15 meters to serve as a buffer zone for flood control. The La Mesa Dam has a watershed area of 27 km2, a height of 33 meters and a crest length of 326 meters. It has a dependable water supply capacity of 110 million liter per day (MLD), augmented by water from the Angat Multi-purpose Dam.


Main Features of La Mesa Dam
Location : Brgy. Novaliches, Quezon City, MM
Coordinates : 14°40’15” N 121°03’ E
Name of River : Tullahan River
Owner : MWSS
Purpose : Water Supply
Period of Construction : 1926 – June 1929
Date of Operation : June 1929
Dam Type : Storage, Earth fill
Drainage Area at Dam site : 27 square kilometers
Foundation : Solid Rock
Crest Elevation (Parapet) : El. 82 m.a.s.l.
Height : 33 meters
Crest Width : 6.0 meters
Crest Length : 326 meters
Base width at maximum section : 180 meters
Embankment Impervious Fill : 630,000 cubic meters
Filters : 99,000 cubic meters

Reservoir
Gross Storage Capacity : 51.03 million cubic meters
Dependable Supply : 110 million liters per day
Maximum Reservoir level : El. 80.15 m.a.s.l.
Minimum Reservoir level : El. 71.00 m.a.s.l.

Spillway
Length : 236.50 meters
Type : Concrete Overflow Structure
Sill Elevation : El. 80.15 m.a.s.l.
Penstocks Type : Plate Steel embodied in concrete
Dimension : 3 – 2.45 meters dia. for the horizontal part then reduces to 2.30 meters dia. for the vertical part

Project Cost (original project) : P 1,875,000 (at 1929 price level)
1st dam raising : P 950,300 (at 1929 price level)
2nd dam raising : P 3,110,300 (at 1929 price level)

Source of Fund : Corporate Funds of MWSS
Construction By : Dimson Construction Co. – For raising of the dam and spillway (1958)

Galauran & Pilares Const. Co. – For raising of the dikes (1958);

Pacifico Austria Co. – For raising of the dike and spillway to El. 80.15 m. (1991)



Source: JICA
http://www.nwin.nwrb.gov.ph/Prog&Proj/JICA...nt/05lamesa.htm

flipzi - October 21, 2009 04:10 AM (GMT)
Reaction from other forum;
QUOTE
From: kit canillas <fxcanillas@gmail. com>
Subject: Re: [CebuPolitics] SOME NAVOTAS UNSCATHED BY ONDOY ?
Date: Saturday, October 10, 2009, 8:01 AM


Alfred the Tullahan river feeds the creek that courses its way to San Juan River.

If traced in google earth, the river from Angat dam has a tributary leading to Ipo and Wawa dam that leads to San Mateo that feeds La Mesa Dam though the main course of the river goes to Plaridel and also to Pampanga.

Somewhere in San Mateo the river forks to Marikina and off to Pasig River and the Manggahan Flood Way.

Tullahan also forks into a big creek in the in the Sauyo, Novaliches area that feeds the creek leading to Tatalon Quezon City and unto San Juan.  The main body of the Tullahahan river though goes to the KAMANAVA area but the descent towards the creek is a bit steep that much water flows into the creek the forks from the Tullahan river at around the Forest Hills Subdivision.  The creek swells to more than a hundred meters wide and around 20 meters deep with heavy downpours and with La Mesa Dam overflowing specially.

When there are heavy downpours and especially when La Mesa Dam overflows, the creek is quite scary with the tremendous rumbling of the furius flow of the swollen creek that already can be consider a river in such a state.  The rumbling as such also occurs just behind West Ave in the Paltok area specifically beside Gen Lim where the creek has a steep turn.  Experienced seeing and hearing this in the 1972 deluge that evidenced the tremendous volume of water that passed through the creek forking from Tullahan River.

The size of the area drained by the creek is huge and is a concrete jungle that heavy downpours definitely produces flash floods.

The convergence into the relatively much too narrow Pasig already loaded with water coming from Laguna Lake and the Marikina River prior to San Juan  definitely slows down flow and produce the flood we experienced in these areas around the creek.


Kit

My Answer;
QUOTE
Kit;


I can believe that since the topography seems to tell like it.

If this is indeed true, what I can suggest is to utilize the 5 river systems to divide the volume of water coming down from La Mesa.

1. Tullahan River 20%

2. Marikina River 20%

3. Santa Maria River 35%

4. Marilao River 25% 

These are suggested division though. Thorough studies are needed.

We cannot use the San Juan River because it is now overburdened. It is draining the entire central part of Metro Manila including much of the Quezon City.
   
The Santa Maria River as per satellite photo seems to be the the best route aside from the Tullahan and Marilao since it has a wide channel and a good depth.

The Santa Maria River can be used by creating another spillway at the eastern part of La Mesa dam.

An existing river snakes out of that part of La Mesa Dam and we can connect that to the tip of Santa Maria River or create a diversion canal.

Also the long route may somehow decrease the pressure of the water flow since some of the volume will seep into the ground or leak out into smaller creeks and canals along the river.

We can also decongest the Marilao River from the Prenza Dam point by connecting  the tip of Meycauyan River to the Prenza Dam.

The construction of concrete dikes (or concreting the banks) are necessary especially in Marilao, Tullahan, as well as Marikina and Pasig Rivers to ensure a smoother and safer flow.

With less resistance (or obstruction) the channels can allow more water volume to pass through.

Then again, technical and feasibility studies have to be made.


Alfred Alexander Marasigan
Manila, Philippines
getflipzi@yahoo. com


This is the illustration of the possible 2nd spillway. The green line is the Santa Maria River and the yellow line is the Marilao River.

user posted image

flipzi - October 21, 2009 04:11 AM (GMT)
Suggested Flood Control Project for QC, Makati and Pasay Residents

(NOT A SUGGESTION by the way, but simply a "REMINDER")

What's often neglected and needed "cleaning up" (declogging/ bank improvement/ dredging/ relocation of illegal settlers / and removal of all illegal structure) here are these 3;

1. San Juan River
2. Canal dela Reyna River
3. Estero de Tripa de Gallina

These 3 cut through a large area and there's no other alternative waterways for those areas.

For Quezon City residents and officials, they need to support the improvement of the San Juan River as well as the Tullahan River. Needed are dikes or bank improvement, removal of obstructions and relocation of shanties.

Canals leading to Tullahan and San Juan Rivers mut be improved or fixed as well.

For the Makati as well Pasay residents and LGU, they need to help "big-time" in the improvement of the "Estero de Tripa de Gallina". From Pandacan tip down to the Paranaque River.

The work must cover all segments. Bank improvements, removal of all obstructions. This will improve water flow, which means more water is flushed out into Manila Bay. The floodwater will subside faster or there's less flooding. Perhaps no more flood at all.

Pumpings stations at some areas maybe needed.

This may solve the flooding along Buendia Ave in Makati as well as the other areas.

flipzi - October 21, 2009 04:12 AM (GMT)
For Pantabangan, Angat and San Roque Dams;

user posted image

A second spillway can be built to dump water into the Pacific Ocean instead of flooding Bulacan towns. There is a waterway sprouting from the nortwestern tip of Angat. We can build a canal or tunnel to connect this to an existing river that leads to the Pacific Ocean.

Water for irrigation will be released from the existing gates. But excess water will be spilled via the new spillway and river system.

user posted image

Pantabangan dam's spillway is taking the wrong route.

The river in that long route is draining water from the vast plains and valleys in Nueva Ecija, Pampanga and Bulacan.

THIS RIVER IS ALREADY OVERBURDENED, especially during heavy rains.

The better alternative is to force water spilled from Pantabangan to take the waterway passing through Dingalan and leads directly to the Pacific Ocean.

This is the much better route.

It will not create so much flood like in Bulacan since it is a much shorter route and it drains a much smaller area only.


With the Bulacan route, the spilled water from Pantabangan mixes with the floodwaters coming down from the valleys and plains of that very vast region composed of Bulacan, Nueva Ecija and Pampanga.

With that of the Dingalan in Aurora that is much shorter and less inhabitted, it will be the better route.

We will need to create a dam or dike at that point near Palayan City to divert the water and make the floodwaters take the Dingalan route instead. Dikes along the route should be built to protect the settlers.

As for San Roque Dam/Ambuklao Dam, there's no other way but to "relocate" the settlers in the danger areas and build dikes to control overflow.

The rationale is that the drainage or capacity requirement for the whole area affected and including the San Roque Dam's spill volume, requires a much bigger channel or waterway.


Other option is to build another dam adjacent to the San Roque that can be used as a holding tank when the dam is in full capacity. This second dam will not be allowed to hold water during normal conditions. The water from the river running through it will be allowed to drain water at the same rate as before.

Then when the San Roque Dam get's filled, the second dam's gates will be closed and excess water from San Roque will be transferred into it.

This second dam will continously drain water but at a much lower rate as compared to the rate of 1500 (cubic meters per second) or more that the San Roque spills when it reaches spill level.

This way the volume of water running down the streams and rivers below will be much lower.

Another option is to divide the water spilled by the dam between several river systems. This way, the volume is not concentrated on a single waterway.

In some areas like Calumpit and in some Pangasinan barrangays, housing technology maybe changed. Instead of the usual design, houses may be built on something like "houses on stilts" concept, but these poles are made of concrete instead of wood or bamboo.

With these, less lives are affected by the big floods that are yet to come and less money spent on rehab and rescue.

flipzi - October 21, 2009 04:13 AM (GMT)
Read this;

A People Caught in Its Own Dung

Written by Ado Paglinawan
Sunday, 11 October 2009 07:44

http://www.mabuhayradio.com/columns/dissen...s-own-dung.html

QUOTE
the revelation of urban planner Felino Palafox, that the flood that occurred with catastrophic proportions, was not an act of God but that of man – “a sin of omission by government and private real-estate developers.”

Palafox exposed that as early as 1977, the World Bank sponsored a study called “Metro Manila Transport, Land Use and Development Planning Project,” that noted the possibility of heavy flooding in at least three sites of urban growth in the Philippine capital, namely the Marikina Valley and its northern and southern parts, the very same areas ravaged by the recent flood.

He identified the culprit as “Urban development . . . spreading into areas which are, in their present state, unsuitable—either because they are low-lying and liable to flooding, or because development is without adequate facilities for the treatment and disposal of sewage (and will just) contribute to the severe pollution of areas such as Laguna de Bay.”

The engineer who took up urban planning at Harvard said there was little infrastructure to prevent flooding and cited the need to construct a spillway in Parañaque to drain excess water from Laguna Lake to Manila Bay.

“The Manggahan floodway between Pasig and Taytay was constructed to drain floodwater from the mountains flowing through the Marikina River into the Laguna Lake. But what happens when the Laguna Lake overflows? Thus the urgent need for the Parañaque spillway to direct excess water from the lake into the Manila Bay,” he said.

Palafox added that the study also proposed dredging the Pasig and Marikina Rivers, so as to remove silt and accommodate more water.

QUOTE
This becomes pertinent since in my article previous to this, I shared Felino Palafox’s lack of recollection why the Parañaque Spillway never saw daylights. As an aftermath of Ondoy that has now elevated itself to a matter of national-security interest, I feel it a patriotic challenge to dig the painful past.

Let us begin by saying that Palafox’s story was incomplete.

The Parañaque Spillway was not conceived in 1977 when Freeman Fox and Associates, a Hong Kong-based urban planning consultancy firm completed the Metro Manila Transport, Land Use and Development Planning Project.

F ollowing forty days from October 11 to November 20 in 1970, three super typhoons – Sening (Joan), Titang (Kate) and Yoling (Patsy) caused a death toll of more than 2,000. At that time, the combination of the three was the worst to hit our country since 1947 as the damage wrecked havoc to the City of Manila, its suburban areas and nearby provinces, in terms of flooding and damage to property. (It would not be until November 1991 when Typhoon Uring would claim more than 5,000 lives.)

As an offshoot of that devastation, President Ferdinand Marcos immediately ordered the updating of studies on flooding and other such waterways issues in Greater Manila. When the comprehensive report came, he issued Presidential Decree No. 3 in 1972 primarily to rehabilitate and reconstruct damaged infrastructure facilities caused by calamities. 

Corollary to this, Mr. Marcos also created in 1973 a policy think tank called Task Force on Human Settlements to look into Greater Manila’s problems brought about by its rapid population increase and urban growth. The body was recommended by the Philippine delegation who participated in a United Nations conference in Stockholm in 1972 where the concept of human settlements was first introduced.

It was primarily on the basis of the recommendation of this think tank that in 1974, President Marcos enacted Presidential Decree 475 to add more teeth to his earlier decree going to the extent of actually appropriating funds for public works for various projects including 85-million pesos for the Napindan Hydraulic Control Structure, 52-million pesos the Manggahan Floodway and 62-million pesos for the Parañaque Spillway.

Due to the increasingly popular demand for effective solutions to nagging problems affecting many if not most of the local jurisdictions comprising the metropolis, such as the alarming increase in slum areas, traffic congestion, environmental degradation, crime, disastrous flooding, and lack of affordable housing, then President Marcos further created the Metropolitan Manila Area (MMA) and the Metropolitan Manila Commission (MMC) to put rhyme and reason in managing the affairs of the country’s premier urban center. 

The MMA, with a total land area of 636 square kilometers and a population then of about 7-million, comprised of 17 local government units, namely: Manila, Quezon, Pasay, Caloocan, Malabon, Navotas, Valenzuela, Marikina, San Juan, Mandaluyong, Makati, Taguig, Parañaque, Las Piñas, Pateros, Pasig and Muntinlupa. The Metro Manila Commission was given both executive and legislative powers. Appointed Chairman of MMC and concurrently Governor of Metro Manila was then First Lady, Imelda Marcos.

This is where Palafox’s story now connects as he unearths a study completed in 1977of which he was a part. The Metroplan sponsored by the World Bank, precisely confirmed the urgency of earlier public works concepts and relevantly provided for a framework for feasibility of component projects for multilateral funding.

It set the motion for a series of World Bank funding for flood control.

For instance the river walls of Pasig River were raised to accommodate a water level of 14 meters—a level that corresponds to the expected depth of flood with a 10-year return period.

Twelve operating-pump stations, each with a capacity to move 167-cubic meters of floodwaters per second were procured and put into operation. The pump stations are operational in Aviles, Balete, Binondo, Libertad, Makati, Paco, Pandacan, Quiapo, Sta. Clara, Tripa de Gallina, and Valencia. There are floodgates in Escolta, Pandacan, and Santo Bañez. This is sufficient to limit flooding, however, to about 0.2 meter depths in the vicinity of the pumping stations. 

But Metroplan’s main highlight was greater than the traditional flooding we have been altogether familiar in Greater Manila. It identified the Marikina Valley, the western shores of Laguna de Bay, and the Manila Bay coastal area prone to catastrophic flooding, earthquakes, and possible changes in topography. 

The first focus revolved around Marikina City because it is most susceptible to flooding because it is a valley, with its Marikina River collecting water from the Sierra Madre mountain ranges on the east and the Quezon City Capitol Hills on the west.

The Metroplan underscored a combination of infrastructure projects, consisting of the Napindan Hydraulic Control Structure, the Rosario Weir, and the Manggahan Floodway, the Marikina Flood Control Structure, the Marikina Dam and the Parañaque Spillway.

The Napindan Hydraulic Control Structure – at the confluence of Marikina and Pateros-Taguig rivers with Pasig River – was envisioned to prevent or lessen the increase of salinity from Manila Bay and pollution from the Pasig River itself from entering Laguna de Bay during times of reverse flow. This confluence is also the downstream endpoint of the Napindan Channel, which is the upper part of Pasig River that connects to Laguna de Bay. The Napindan project was completed in 1983.

The Rosario Weir is the sluice or floodgate from the Marikina River onto the Manggahan Floodway. The weir was completed in 1984.

The Manggahan Floodway, on the other hand, was proposed and built to keep the floodwaters out of Metro Manila, particularly in Pasig and Marikina, by diverting the flow to Laguna de Bay. The floodway was completed in 1986. 

What the Parañaque Spillway was all about is exactly the answer Palafox gave to his own question “What if Laguna de Bay overflows?” The spillway to be situated further southeast of Makati, was supposed to have been built to siphon runoff from Laguna de Bay when it overtops, onto Manila Bay and the South China Sea. 

Why it was urgent and absolutely essential is now what Typhoon Ondoy has fatally confirmed.

flipzi - October 21, 2009 04:14 AM (GMT)
Flood Control Technology;


SMART Tunnel in Malaysia
http://www.youtube.com/watch?v=qYaO1LM4Dvc

http://www.youtube.com/watch?v=ekNWzu0njn0


National Geographic
http://www.youtube.com/watch?v=fhvV3Zuf8Lo



Im not saying we follow the exactly same.

Point is if we can make technology work for our case, then why not let give it a try.

flipzi - January 27, 2010 06:54 AM (GMT)
GMA OKs Manila Bay-Laguna Lake spillway
By Paolo Romero (The Philippine Star) Updated October 28, 2009 12:00 AM

MANILA, Philippines - President Arroyo gave the go-signal yesterday for the construction of a new water spillway in Metro Manila connecting Laguna de Bay and Manila Bay to prevent massive flooding in the nation’s capital.

During the joint Cabinet-National Disaster Coordinating Council (NDCC) meeting in Pampanga province, Mrs. Arroyo also ordered the placement of sandbags and pontoons or floating bridges in flooded or flood-prone areas in Metro Manila as one of the immediate measures recommended by noted architect and urban planner Felino Palafox during the discussions.

Palafox said the Arroyo administration should not take the blame for the disaster that hit Metro Manila as previous governments and local officials have not fully implemented World Bank-funded plan for the region in the 1970s that could have prevented not only massive flooding but congestion.

He said the flooding patterns in Metro Manila when tropical storm “Ondoy” hit was the same in the 1970s.

Palafox was commissioned by the World Bank in the 1970s to draw up a plan for Metro Manila that includes preventing it from being congested and flooded. Only the Manggahan Floodway in Marikina City was implemented in the plan to control flooding, he said.

“It’s like having a toilet without a flush,” Palafox told the Cabinet.

For the immediate term, Palafox suggested sandbagging in still-flooded parts of the capital and let pumps drain out the water. He also pushed for the placement of pontoons or floating bridges as alternative walkways now that sidewalks are underwater.

For the medium term, he pushed for the construction of the Parañaque spillway, the plans for which were drawn up in the early 1970s, putting up flood alarm systems, and reviewing and amending some provisions of the Building Code.

“There’s a big disconnect between the regulatory regime and the real estate developers,” Palafox said.

“In the meantime, we have what we can do between now and the end of the year, in the immediate, the sandbagging is a very, very good and practical,” the President said. “And we should already ask the Department of Public Works and Highways (DPWH) to work on the spillway.”

Long, winding spillway?

Mrs. Arroyo cited a proposal that in order to minimize the cost of right-of-way and minimize displacement of residents and commercial establishments, the flood spillway should be built in government lands such as that along the Ninoy Aquino International Airport (NAIA).

Mrs. Arroyo said the proposal calls for the use of the entire length of the runway along the fence towards the Parañaque River, on the end of the runway along C-5 Road or Taguig City.

“The spillway can pass to the Food Terminal (in Taguig City) then on towards the Laguna de Bay. That will use government lots and less relocation of homes,” she said.

Palafox, however, said the proposal would make the floodway too long compared to the original Parañaque spillway of only eight kilometers.

“We will have to look at the cost effectiveness (of the project), but it’s an option, in other words it has to be the cheapest way to do it,” Mrs. Arroyo said.

Palafox said not only cost but speed should be the consideration in undertaking the project as Metro Manila is hit by floods several times a year.

Among the flood-prone areas in National Capital Region and nearby provinces, he said, are west of the North Luzon Expressway, Marikina, Pasig and other parts in eastern Metro Manila, and western shores of the Laguna lake.

With the Parañaque spillway, in the worst-case scenario of flooding, the floods would only remain in Metro Manila for 20 days. Without it, the floods could stay over 65 days, he said, citing data from the DPWH.

He said compounding the situation was the heavy siltation of the Pasig River caused “not only by the urban poor but also the urban rich.”

Mrs. Arroyo said the Palace has already begun removing structures in the Malacañang complex that encroach on the Pasig River.

Palafox said the spillway could be considered expensive but the destruction and loss of lives caused by flooding in the past decades are much more costly.

The President also directed Metropolitan Manila Development Authority Chairman Bayani Fernando to publish the earthquake maps and fault lines in the region.

Palafox told the Cabinet that officials of the Philippine Institute of Volcanology and Seismology told him that they were prevented from publishing such maps as it would reduce real estate values in the capital.

Among the other proposals of Palafox that got the nod of the Cabinet were the permanent relocation of residents in high-risk areas, establishing a 100-year flood history, construction of elevated walkways above floodlines, having residential and commercial communities gather rainwater that could be used for other purposes, and clearing the Pasig River.

http://www.philstar.com/article.aspx?artic...ubcategoryid=65

flipzi - January 27, 2010 07:02 AM (GMT)
After the floods, now the need for another dam to address the water shortage

Read this;

Wawa Dam or Laiban Dam?

First posted 00:34:38 (Mla time) January 25, 2010
Neal Cruz
Philippine Daily Inquirer

A long hot summer is almost here and, with it, a shortage of water. The Metropolitan Waterworks and Sewerage System (MWSS) has already warned the public that the water level behind Angat Dam is below normal, reduced the amount of water flowing from Angat to La Mesa Dam and asked Metro Manila residents to conserve water or else their faucets would run dry. This happens almost every summer, by the way, although parts of Metro Manila and Central Luzon are flooded during the rainy season. In fact, after Typhoon “Ondoy,” there was so much water behind several dams in Central Luzon that they had to open the gates to let more water out before the dams break. It is this extra water from the dams that is believed to have flooded Central Luzon and Metro Manila to unusually very high levels. And yet, only a few months later, the MWSS tells us that there is not enough water in the reservoirs and there would be a lack of water this summer.

The water lack comes as surely as the long dry season comes around March, yet the MWSS and other water agencies do not do anything either to conserve water that is plentiful during the wet season or to make use of reservoirs that are already there brimming with water.

I am referring to Wawa Dam in Rodriguez (formerly Montalban), Rizal. The MWSS itself tells us that Wawa is good for at least 50 million liters of water per day (MLD). That is enough to fill up the expected shortage this summer, but for some strange reason, the MWSS and the National Water Resources Board (NWRB) refuse to allow, for the last 13 years, San Lorenzo Ruiz Builders, which owns the water rights of Wawa, to harness it and start water flowing again to La Mesa Dam only four kilometers away. San Lorenzo is willing to spend for it; the government will not spend a single peso, but our water agencies play deaf and dumb, other media outlets play deaf and dumb and Malacañang has been playing deaf, dumb and blind. For 13 years, I was a voice lost in the wilderness crying “Harness Wawa Dam, Harness Wawa Dam!” Wawa, after all, was the lone supplier of water to Manila from 1908. In 1968, when Angat Dam was finished, Wawa was decommissioned. But the supply from Angat is no longer sufficient, so why not harness Wawa again, I kept saying, to supply the expected shortages every summer?

Happily, last Saturday, another voice, also in the Inquirer, made the same cry. He was Reynaldo G. Geronimo, a partner of the Romulo Mabanta Buenaventura Sayoc and De Los Angeles law firm, who wrote that Wawa “is still structurally sound and needs only some repairs that can be done immediately.”

I also received a letter from Oscar I. Violago, president and CEO of San Lorenzo Builders and Developers Group Inc. (SLBDGI), saying that the water volume of its Wawa Dam Project is not limited to 50 MLD, as MWSS makes it appear.

“TGGI engineers, one of the accredited technical consultants recommended by NWRB, validated water flows at Wawa River of at least 16.64 CMS or approximately 1500 MLD,” Violago wrote. “TGGI’s findings only confirmed previous studies conducted by Picorem, Electrowatt Engineering, Knight-Piesold, Bureau of Research Standards and even CTI Consultants, the firm engaged by MWSS in 2005 to make a study of the Wawa Dam Project. This can be further increased with engineering improvements and reforestation programs.”

The existing dam can produce from 50 to 80 MLD, and can be rehabilitated in less than eight months, Violago said. More small dams will be built upstream of the existing dam to increase their holding capacity. The first of these will have a height of 45 meters, Violago said, and can be built within 18 months and will have a capacity of 500 MLD.

“If the Boso-Boso Dam will simultaneously be built, the capacity will be increased to 900 MLD,” Violago continued. “Wawa Dam’s full water production of 1500 MLD can be operational within four years.”

The transmission cost will be much less since Wawa is only four kilometers from La Mesa Dam, with an existing right of way, and the implementation lead time is much shorter than that of Laiban Dam in Tanay which is being proposed by San Miguel Corp. Laiban is 70 km away, requiring 30 km of tunnels.

Water production of Wawa and Laiban’s watersheds are almost the same, Violago continued. Wawa’s watershed is 27,700 hectares, almost the same as Laiban’s 28,000 hectares. The watersheds are beside each other and have the same rainfall patterns and weather conditions.

Furthermore, the Wawa Dam Project has tremendous advantages over Laiban, Violago claimed. It can be operational within a year. On the other hand, Laiban’s proponents say they will need at least five years just to relocate the squatters inside Laiban’s future reservoir. (The Japan Bank of International Cooperation says that, from its experience, it would take 10 years.)

From Laiban’s own timetable, had it started activities in 2007, it would be operational by 2015 or in eight years, Violago wrote. “It is now 2010. The earliest it can be operational, optimistically, would be 2017.”

Wawa Dam, unlike Laiban, can be undertaken by stages, dependent on the requirements of the concessionaires, so that there would not be any take-or-pay provisions from MWSS’ two water concessionaires, Manila Water and Maynilad Water, Violago continued. If MWSS succeeds in imposing a “take or pay” provision on 1900 MLD on its concessionaires regardless of whether or not they need this huge volume of water immediately, then the price to their consumers would triple immediately. This would burden Metro Manila residents.

Moreover, Wawa Dam’s investment requirements can be staggered and be more manageable over several years, instead of a one-time outflow, Violago said.


Copyright INQUIRER.net. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


http://archive.inquirer.net/view.php?db=1&story_id=249274


Related article:

Harness Wawa Dam now and avoid water lack

http://archive.inquirer.net/view.php?db=1&story_id=247337

Laiban Dam Project
by PCIJ

http://pcij.org/resources/laiban-02-chronology.pdf





flipzi - January 27, 2010 07:45 AM (GMT)
user posted image
Laiban Dam Project
http://pcij.org/resources/laiban-02-chronology.pdf

The Laiban Dam project is not bad at all. But if we will join it with the La Mesa Dam through the 30km pipe then it becomes questionable. What I would suggest is building another dam upstream from the location of the Wawa Dam in Rodriguez/Marikina area.

See map below;

user posted image

The second biggest benefit of this project is that the rainwater rushing down from the slopes of the surrounding mountains in the southern part of the Angat Watershed will be funneled into the new dam instead of flooding the Marikina River (and the Marikina Valley).

The dam can then gradually spill the water into the Pacific Ocean or hold it for later consumption if the dam's water volume is still not at alarming levels.

It will then spill the huge volume of water right into the Pacific Ocean via the enormous Agos River that ends in Infanta, Quezon.

With this we have achieved two vital goals. One is considerably reducing the floodwaters going into the Marikina Valley. Second is the new source of potable water and irrigation for the communities.

Then again, I am not sure if it's indeed possible (economically) to build a large dam in that area that's enough to hold a huge volume of rainwater since the lower portion of the area seems to be too wide to build a dam that will seal off the southern edge and hold the water.

The new dam project can also be made to consist of 3 dams in series. The first dam is situated at higher slopes and where it is possible to build the first dam. The second dam maybe situated 20 kilometers downstreanm or where it is economically possible to trap the water flow. The spillway must be designed to dump water into the Agos River that leads to the Pacific Ocean.

user posted image

The 3rd dam can be the old Wawa Dam. It must be raised to be able to hold more water. The water at this point have no other path but the Marikina River. Good thing is it can still control floodwater and since the 2 dams upstream are dumping water into the Agos River, there should be less water flowing into the Wawa River.

The 2nd dam by the way can also be made to divert water when needed into the Wawa Dam during the summer months to support La Mesa's supply.

As for Laiban Dam, we may pursue it but it must not be connected to the La Mesa anymore but be made to serve the different water service companies (or cooperatives) and facilities around Tanay, Baras and other possible service areas.

The dam can be utilized for irrigation as well.

The most important thing that we must do is to have its spillway lead to the Agos River instead of the Laguna Lake or Marikina River.

Instead of building a 30 km pipe to connect the dam to La Mesa, we should instead build that pipeline to find a way into the Agos River for draining excess water.

flipzi - January 28, 2010 01:54 AM (GMT)
user posted image

As for the way to link the spillway to the Agos River, we may need to build a tunnel. Maybe 10km or longer.

The challenge is that the elevation of the river going eastward that connects to the western tip of that pipeline is probably lower than the opposite end of the pipeline connecting to the Agos River.

It should be the opposite so the gravity can direct the water to flow eastward and into the pipeline that leads to the Agos River. We will need to redirect the current water flow, which is westward (going to the Marikina River). This involves working on the elevation.

But if the elevation of eastern tip of the pipe can be made lower compared to the western tip of the whole stretch up to the spillway, then there's a great chance that this will work.

The capacity of the river against the maximum amount of water that must be spilled when the dam reaches spilling capacity must also be checked.

Another is the possibility that the huge volume of water spilled by the dam at maximum levels may escape the river channel as it overflows and sweeps the southern slope and the valley down below, which are probably inhabitted.

A solution would be to build concrete dikes across the entire stretch of the river connecting to the pipeline or by dredging the river.

So, a thorough study must be carried out.

If this project pushes through, we can really divert the rainwater rushing down from the southern slopes of Mount Cayadlas and Mount Irid (southeast of the Angat watershed) to the Agos River, which then dumps the floodwater into the Pacific Ocean instead of the Marikina River-Pasig River system.

Also, an added source of potable and irrigation water for the surrounding community and farmlands.

biofuelswork - November 15, 2010 04:46 AM (GMT)
I am writing more suggestions to the LLDA to control floods around Laguna Bay (and Metro Manila) similar to those described above but which are not-expensive, easily-doable and quick-acting.

A draft of my thoughts can be viewed at my website: www.biofuelswork.com particularly at the tab entitled "Catching & Keeping Rain"

As I finalize my report and before I send it to the LLDA and upload it to my website, may I ask that we discuss this topic again so that we can put our heads together and come-up with better ideas.

Gerry

eman - November 16, 2010 03:54 AM (GMT)
Gerry,


Thanks for dropping by.

The article you made was worth the read!

I agree on the small dams built along creeks to contain water and maximize utilization during the summer months.

I agree on the holding pond as well. You may suggest the DENR or NGOs or civilian efforts undertaking tree planting projects to consider building these holding ponds so that the water absorved or held in these ponds will sustain the life of the fragile young trees or seedlings.

Best of all, small in scale for each individual, but when all do this;
QUOTE
Keeping trash (specially plastic bags and those contained in them) from getting into waterways is highly recommended. They are the bane of flash floods (from the esteros) in Metro Manila. The efforts of merchants in Paete, Laguna to stop using plastic bags and residents of Liliw, Laguna to keep their streets clean of trash (even cigarette butts and candy wrappers) are commendable and should be emulated by others as these efforts will also help minimize and control flash floods in addition to their other great benefits.

... it will help lessen the damaging effects of heavy rains.

Your suggestion is reasonable.

Follow your heart.

Good luck!

biofuelswork - November 16, 2010 11:30 PM (GMT)
Dear Eman,

Besides making small holding ponds and/or undertaking tree planting efforts, I recommend the planting of trees or vegetation around the ponds to promote water retention in and around the ponds.

I am not an agronomist so the following statements may be in-accurate. I mention them in the hope of getting feedback and generating discussion so we can learn from them.

While tree-planting can help create or restore watersheds, I believe it must include tree species with sponge-like root systems that absorb and store water. Surely some trees consume water and some are capable of storing it for future use (as camels and cactus do.)

Tibig: I heard about them and checked them out. The web contains some info. In the field -- they can be found in abundance where "sibols" or spring waters exist. People familiar with them say they are capable of storing water.

Madre de Aqua: Information on the web indicates that its leaves, cuttings and green stems can be used as food for livestock. I hope it is not like "ipil-ipil" that lost favor after it was propagated. The "Aqua" in its name, however, intrigued me and led me to this statement in a Livestock Research for Rural Development Report:

QUOTE
It has also been used . . . for shade and for protection of water springs (Perez-Arbelaez 1990; Devia 1988; Gowda 1990).


How do these plants do this? Are there any other similar plants out there? I believe tree planting to create or replenish watersheds will improve if vegetative ecosystems are also restored and preserved by re-planting indigenous tree species like these.

I look forward to your comments and/or feedback. Thank you.

G e r r y


eman - November 17, 2010 01:35 AM (GMT)
In fact, the ponds and trees will complement each other or sustain each other.

The stored water in the pond will sustain the water requirement of the trees and plants.

On the other hand the shelter, the canopy, will lessen water vaporization. The roots will prevent soil erosion.

I also recommend fruit-bearing trees so that the wildlife, especially the birds, will help sustain the spread of the tree seedlings.

The birds will feed on these fruits and their droppings will help spread the growth of plants and trees.

So, even if the human efforts on the reforestation will stop or slow down, these birds will sustain the reforestation.

biofuelswork - November 21, 2010 03:14 PM (GMT)
Collecting RAIN and Storing It appears to be a good solution that the Cities of New York and Philadelphia and the US Environmental Protection Agency (EPA) are studying and implementing. Read about it on:

Water-saving in the north-east
Trees grow in Brooklyn
A natural form of relief for overworked city sewers
http://www.economist.com/node/17468409
http://www.economist.com/node/17468409/comments#comments

After reading this post and the above articles, please give it more thought and let us discuss it. Floods caused by rainwater and rainwater that goes to rivers (overwhelming them and causing havoc) are a WASTE of fresh water that we can save and use later. By putting our ideas and heads together, I am sure, we can develop for the Philippines long-term, sustainable and environmentally-safe solutions as being done now in New York and Philadelphia and soon in other parts of the USA.

Thank you for your kind attention.

G e r r y

flipzi - December 1, 2010 05:09 PM (GMT)
QUOTE
New York recently unveiled a grand plan to clean up its waterways. Instead of spending billions on new tanks and pipes (ie, “grey infrastructure”), which take years to build and never quite address the problem, the city intends to invest in “green infrastructure”, such as roofs covered with vegetation, porous pavements and kerbside gardens. The scheme involves a fundamental shift in approach: instead of treating rainfall as waste to be whisked away as quickly as possible, New York will let it sink usefully into the ground: thereby helping to make the city greener, improve air quality, raise property values, increase jobs and lower water and energy costs, according to studies by the EPA and others.

This is no unfunded pipe-dream. The city is already required to spend $6.8 billion over 20 years to meet harbour-quality standards. The greener plan would cost government a third less, with $2.9 billion for tunnels and tanks and $1.5 billion for green innovations. New buildings would also have to meet run-off regulations.

This is a way of achieving more than one thing with tax dollars, says Carter Strickland, a deputy commissioner in New York’s Department of Environmental Protection. Unlike a sewage works or a new pipeline, which take years to build and which no one wants nearby, green infrastructure projects offer benefits the moment the first tree is planted or a rain barrel is installed. “Isn’t it nice?” observes Mr Strickland as he shows off one of the city’s 30 pilot projects, a little roadside garden deep in Brooklyn, with a tree and some flowers. It is indeed, and it can capture nearly 1,000 gallons of storm-water that would otherwise pour into a nearby drain.

http://www.economist.com/node/17468409


This sounds like a good endeavor. The option will work but if you will consider flash floods like a Typhoon Ondoy category or so, this will not be enough.

What we need to look at is building more dams to hold more water.

Also, improving the existing dam's capacity. Remember that they openned the gates of the big dams like the San Roque Dam in Pangasinan and even the Angat Dam when heavy rains exceeded the capacity of the dam.

So, as it tells, what we need is to build more dams and improving the existing dam's capacity.

For the flood run-offs, we need to fix and improve those flood-control systems. This will include widening or declogging of the major esteros. As well as building the second spillway for Laguna de Bay that will traverse the areas of Paranaque. Please see image below;

user posted image


biofuelswork - December 2, 2010 08:54 AM (GMT)
Thank you for replying & choosing portions in The Economist article that best apply to this discussion.

I agree that we have to build more dams; improve existing dam capacities; and, fix and improve flood-control systems like widening or declogging major esteros and building a second spillway for Laguna de Bay through Paranaque.

However, these are solutions that primarily need to be done by our government.

To solve our flooding problems around Laguna Lake and elsewhere, "non-government" initiated projects may be a quicker, more-economical and effective.

The rainwater impounding ponds I propose, although they may only contain a limited quantity of say 50 m3 or 50,000 liters each if built in 10m L x 5m W x 1.5m D dimensions, may actually be able to prevent 500 m3 or 500,000 liters of rainwater run-off that cause floods by facilitating the absorption of that water into the ground (thereby replenishing the aquifer also.)

100 ponds will prevent 50,000 m3 of run-off; 1,000 will prevent 500,000 m3 of run-off, etc.

This is easier said than done. My pilot project of 2 small ponds (10 m3 capacity each) may have prevented 200 m3 or 20,000 liters of water from running-off into Laguna Lake in this prevailing "low" rain season as they alternately filled-up and dried. Unfortunately, they also filled-up with soil again and contain no water for use in the coming dry season. The ground around in the pond, however, seems to be saturated with water.

I hope by discussing and perfecting solutions like these that farmers can make by themselves we can begin making more of these ponds everywhere. Taken to an extreme, upland fishponds supported by stored rainwater/replenished aquifers -- if given a bit more thought by us -- can be developed into long term, ecologically-sound and sustainable solutions that can be profitable too.

biofuelswork - December 2, 2010 09:05 AM (GMT)
And, since government projects are of interest to us particularly the "confusing BILLIONS of pesos issue" involving the DREDGING of Laguna Bay, why can't we just leave the silt where it is now.

So what if the Laguna Bay will rise and flood more areas. At best, its surface area will increase; store more fresh-water into the surrounding aquifer; and, enable water to flow out (instead of in & out) into the Pasig and Manila Bay.

The BILLIONS, that will be spent (or wasted?) for dredging should instead be used to build planned and sustainable communities in the uplands / mountains east of Laguna Bay where illegal settlers all over Metro Manila & around Laguna Lake may be encouraged to move.

flipzi - December 2, 2010 12:55 PM (GMT)
I agree as well on the setting up of small ponds for small farmers, especially those in the upland and those who have large area (1 hectare or larger). The ponds built will somehow mitigate the effect of low rain or drought.

I would suggest concreting the pond's wall to hold water longer. Similar technologies maybe used to keep the water from being absorved by the surrounding wall and the soil beneath.

Better if we can cover it with tarpauline or other inexpensive material as well so that evaporation during hot summer will be lessened. The cover is removed during the rainy season and it should be installed during the summer months only.

But if the pond will be used for aquaculture, then we may not need the cover anymore. The pond can be also be used for aquaculture to provide additional livelihood or for home consumption.

Proper scheduling must be analysed carefully so that irrigation and the benefit of the aquaculture will not be in conflict.

Fingerlings must be placed during the start on the rainy season. 3 months may be enough to harvest the maturing fish. Then the second set of fingerlings may be released. After another 3 months or right before the pond dries up during summer months, it is harvested.

As for the Paranaque Spillway, the cost of the project is nothing compared to the cost of private and private infrastructure that will be protected.

More important than that is the saving of many lives from flashfloods and destruction of homes and livelihood.

We cannot simply let the Laguna Bay work as how you pictured it. The Laguna Bay is not just protecting the communities around Laguna Bay but it extends up to Marikina, Cainta, Antipolo, Quezon City, among others.

The Laguna helps control the massive flood. We cannot widen the Pasig River anymore because of the many structures that have been built along the river.

Worse, all the floodwaters are dumped into the Pasig River.

The only solution now is to "lessen the burden" of that river. That is by creating another outlet that will help flush the excess waters out into Manila Bay.

biofuelswork - December 5, 2010 04:53 AM (GMT)
Concreting the ponds will be too expensive. New materials like HDPE are cheap & easily installed.

Thick HDPE liners keep water from seeping-out into the sandy-loam soils underneath the man-made 12 hectare lake of Lakeshore in Mexico, Pampanga. Eton City's 35 hectare man-made lake in Sta Rosa, Laguna probably uses it too. See: http://lakeshore.com.ph/homehtml & http://www.etoncity.com/

Our "hito" or catfish experimental grow-out fishponds, use thin & cheap HDPE liners that seem to work very well. At any rate, some soils (clay?) may actually have good water-holding capacity and do not need to be lined.

1. Surrounding the ponds with plants like Tibig that store water (like sponges?) and giving them a canopy of trees or perennial vines like peppercorn (for profit?) or Buhok ni Maria (for aesthetics) should be helpful in minimizing water loss to evaporation during the dry season.
2. The ponds must drain and saturate their surroundings with water during the wet season (to replenish the aquifer & the watershed.)
3. Choosing locations that can allow the ponds to be replenished (with water dextrosed-from higher locations or pumped-up from nearby streams or rivers) during the dry season should also be helpful.

Thank you for discussing this with me. I hope others will join us towards developing better IDEAS. We don't have to look far to see that this idea must work. Water that irrigates the "world famous" Bananue Rice I am sure are accomplished by similar innovations.

flipzi - December 5, 2010 03:19 PM (GMT)
When you mentioned liners, I remembered the Koi ponds using these liners as well.

I agree on all you said.

Better if we can use indigenuous materials or other technologies to replace the commercially available liners.

I was surprised you mentioned the Banaue Rice Terraces. I was planning to start a thread about how the whole community works harmoniuosly with nature. I was planning to have that serve as a model for proper zoning or village planning. I will complete that article within 2 weeks.


biofuelswork - December 6, 2010 04:04 AM (GMT)
QUOTE
flipzi  Posted on Dec 2 2010, 08:55 PM
The only solution now is to "lessen the burden" of that river. That is by creating another outlet that will help flush the excess waters out into Manila Bay.


I mentioned in a previous post why can't we just leave the silt (in Laguna Bay) where it is now. This was not meant to say that projects meant to flush-out excess waters must be abandoned or not pursued.

I was just being concerned about the BILLIONS the previous administration want to spend in removing Laguna Bay’s silt (by dredging to be done by a Belgian company.) I agree that President Noy must rescind and scrap this plan.

Besides using said BILLIONS to build one or more outlets, the bulk in lieu of dredging, must be used:

1. To establish sustainable communities (complete with business & livelihood facilities) in the uplands / mountains east of Laguna Bay where illegal settlers all over Metro Manila & around Laguna Lake may be encouraged to move and

2. To find ways, as I have been suggesting, like:

Preventing Rainwater from rushing down from the uplands (causing landslides, run-offs and un-abated silting in the bay) and
Collecting & Keeping Rainwater in the uplands (to saturate/replenish upland ponds/reservoirs/watersheds/aquifers with water that can be used to scientifically water/drip-irrigate plants in the dry season)

3. Other projects like tree-planting because they should be on-going by now and although permanent & long-term, however, cannot produce the necessary solutions/results we need immediately – hence this call for more innovative ideas & discussions.

To attract more attention and develop more ideas in this discussion, I linked it to my thread on the PCCARD Message Board. I hope you do not mind.

G e r r y

flipzi - December 6, 2010 01:28 PM (GMT)
Gerry;


You are right on the scrapping of the dredging of the silt for now. The billions of pesos allocated can be rechannelled to more pressing projects like the second spillway.

As for the sustainable communities, it is a complicated case in fact. A poorly planned relocation will be futile like what normally happens if the vital fators are not addressed properly.

These are, livelihood or promixity to sources of livelihood or work and proximity to schools. Other factors are electricity and water supply. Last is payment scheme.

If these factors will be included in the project, the success rate will be better. Otherwise, it will fail or the result will not be that satisfying.

As for the the upland projects addressing rainwater flashfloods, there is one thing that i noticed in how Metro Manila was designed. THERE WAS NO MAJOR PROJECT UNDERTAKEN THAT WOULD HAVE ADDRESSED THE FLASHFLOODS.

I have viewed the network of waterways covering the areas from the surrounding barrangays of the La Mesa Dam area down to Kamanava and Manila.

The Mangahan floodway, which includes the Laguna Bay as its catch basin, and the Navotas Flood Control Project are excellent projects but these are not enough to handle all.

The floodwaters starts from the areas surrounding La Mesa Dam. These includes Fairview in Quezon City.

user posted image

user posted image

We need to complete the network of large waterways to drain the flashfloods into Manila Bay.

I suggest these;

1. Creating a floodway from the La Mesa Dam area that will dump the water into Manila. Probably a widening of the Tullahan river.

2. Construction of the Paranaque Spillway to decongest the Pasig River.

3. Improvement of the San Juan River to improve capacity. The floodwaters from Fairview area run through this river.

4. Improvement of the Marilao River System to enhance capacity. This river drains the floods from the northwestern slope of the La Mesa watershed.
QUOTE
Marilao River (major channel)
1. Drains water from Marilao, Meycuayan and as far as the nothwestern side of the La Mesa Dam area.
2. Two other rivers, the Meycuayan River and Polo River that drains Malabon and Valenzuela dump their water here.
3. Another great rivers, the Santa Maria River and Balagtas River meet up with the Marilao River in the Obando area before reaching Manila Bay.

5. Reconstruction of the Wawa Dam to lessen floodwaters running down the Marikina-Pasig River System.

6. Construction of the Laiban Dam to lessen floodwaters leading to Laguna Lake.

7. Construction of the floodway that will drain the rainwaters from the southeastern slopes of the La Mesa watershed. This floodway leads to the Pacific Ocean via the Agno River in Quezon. A tunnel may also be needed to link the floodway to the river in Quezon.

8. Construction of a dam instead of the floodway mentioned above. The dam will be constructed in Rodriguez, Rizal.

9. Major reforestation to slow down rainwater flow.


As for this;
QUOTE
2. To find ways, as I have been suggesting, like:

Preventing Rainwater from rushing down from the uplands (causing landslides, run-offs and un-abated silting in the bay) and
Collecting & Keeping Rainwater in the uplands (to saturate/replenish upland ponds/reservoirs/watersheds/aquifers with water that can be used to scientifically water/drip-irrigate plants in the dry season)

I have no idea at the moment. My concern is that the approach must be acceptable to the homeowners. The limitation is land area. For those with large lands, they can simply construct ponds to hold water or use it for aquaculture and for irrigation. Nonetheless, most of the homes around La Mesa in the western side dont have such wide spaces.

So, the approach must be applicable to how the community is arranged.

flipzi - August 7, 2012 02:39 PM (GMT)
2 years after the Ondoy flood comes another

This photo of the Manggahan floodway proves that Metro Manila needs a second floodway.

user posted image

QUOTE
Rampaging floodwater rush through the Manggahan floodway along the Marikina River as seen in this photo taken from Ortigas Avenue extension on Tuesday afternoon. People living near the floodway have been evacuated to safer ground. Twinsy Adajar via YouScoop

http://www.gmanetwork.com/news/photo/23332...-of-overflowing


Marikina River

user posted image

user posted image

user posted image


video
[dohtml]
<iframe src="http://www.gmanetwork.com/news/evideo/129215/provident-village-sa-marikina-lubog-na-naman-sa-baha" width="640" height="380" frameborder="0"></iframe>
[/dohtml]

flipzi - August 8, 2012 01:15 AM (GMT)
if the national govt does not implement such big projects, the devastation will be repeated over and over again and perhaps it gets worse everytime.

to protect long-term investments, thousands of families across Metro Manila may be forced to leave their homes and relocate to higher grounds.

now, imagine the ghost towns that will be created and its economic implications?

far from reality but still a possibility.

but what if?

the long-term effect will costs the govt much more.

flipzi - August 8, 2012 02:26 AM (GMT)
Dregde Laguna Lake or build the 2nd Spillway?

Both will be helpful but we are talking of funds here as well.

The better option in my point of view is the spillway.

Why?

Even if you dredge the lake, the prolonged downpour will still render it useless because the volume of silt that was taken out of the lake is much less than the volume of water that will be created by the prolonged downpour just like the "1st week of August 2012" scenario.

The lake was considered to complement the Manggahan floodway. It serves as a catch basin. The water from the Marikina River is taken in. But the moment it gets filled up, the water flow will be reversed, it will be released and drained into Manila Bay via the already overburdened Pasig River.

So, this is how it goes. With the plan to dredge the lake but without building the 2nd spillway to decongest Pasig River, it will be futile.

Worse, as per residents themselves, the water level in the lake rise up fast but it takes much longer to subside to normal levels. Usually, they added, it takes days before the water level subsides.

So, even when the typhoon is over, it takes days before the flooding across the effected areas to subside since the lake, which serves as the catch basin, takes long in draining the floodwater into Manila Bay via the overburdened Pasig River.

The best is to prioritize these;

1) Build the 2nd spillway west of the Laguna Bay.

2) Widen/dredge the Major River systems (reclaim)

3) Build dikes or dams in critical points along the river systems.

4) Relocate residences in safer zones to minimize casualties.

5) Build a 2nd floodgate for La Mesa dam that will drain the water into the Pacific instead.


Then we dredge the lake to make it hold more water.

All these working together will help lessen the effects of the floods.

flipzi - August 8, 2012 05:51 AM (GMT)
yes, indeed. not nature. not the heavens. but proper management and planning.
QUOTE
Don't blame the floods to God. God made rivers and water ways so that rain water could go through it. MODERN humans, whom they supposed to be INTELLIGENT humans, back-filled the rivers and water ways, denuded the forests that holds the waters in the mountains, and dumped garbage to the narrowed rivers which resulted to severe flooding when heavy rain pours. Rain is a blessing to farmers. It is something to be happy about if we only used our natural resources properly.

- Erick Quinto




* Hosted for free by zIFBoards