Catchment areas is a large area bounded by watersheds draining into a river, basin or reservoir. This is an area that absorbs water that contributes to a specific region's surface or groundwater supply. Digos Catchment Area is an enclosed area where large part of the Davao River water are stored in large natural basin. This is a protected area by the Mindanaoan government particularly in the Davao Region because this is one of the major source of clean and potable water. The specific agency concerned in water supply is the Davao Region Water District (DRWD).
How do they process those water from the river?
1. First of all, the Catchment Area's main tributary river is the Davao River connected by a river drop (small waterfalls).
2. Water from the river drop goes through the 10 hectare-meter (average volume of lake per meter depth) natural basin forming a lake.
3. An artificial channel have been created to divert the flow of water from the basin to the water processing plant (see corner left part of the above picture). Since large volume of water is being diverted, engineers decided to put up another small lake called the Forebay to minimize the energy dissipated by the large volume of water. (Water can be very destructive!) Water that is ready for treatment are collected in the forebay. The water in the forebay, on the other hand, is supplied by the natural basin.
4. After passing through the forebay, water is then transported through a conveyance channel flowing in the water treatment plant. A flood gate have been constructed to control the inflow of water to the treatment plant especially after heavy rainfall. Just after the flood gate is a large filter where organic materials such as dry leaves are separated from the water. (No filter in the pic! hehehe...) This is the first step of treatment.
5. Water now enters the Treatment Plant for disinfection of dangerous microorganisms. DRWD utilizes chlorination as the primary way of treating water. However, during summer where sun is extremely hot, they use UV rays to kill those microorganisms present in water.
6. After treating, the water is now stored in a very large storage tank ready for direct supply and for future use. Two large pumps are installed to distribute the water from the storage tank to another pumping substations.
7. This is the process of distributing water: Main pumping station --> Pumping substations --> Usage. Water are used for domestic, civic, trade and industry, and public purposes. Of course, we should also account for losses.
So that's it! That is their process of making use the water from the Catchment Area. However, let us look on the other side of this process.
Water from the catchment does not permanently remain in the basin and not all water from the basin is used for water supply. DRWD never disturbs the natural system of the river. Natural spillway channel drains the excess water from the basin.
The flow of the natural spillway channel then undergo a certain drop of elevation forming another waterfalls which makes a perfect view from the McArthur Avenue.
And finally, the excess water (or tailwater) goes back to the natural flow of the river which sustains life for other living organisms.
The Digos Catchment Area is also a popular spot for educational field trips. This is also a good tourist destination because inside the area is the replica of the Palace of Fine Arts.
Just a few reminders... The catchment area is a protected place. Hence, visitors are allowed only to tour inside from 9:00 am to 7:00 pm and only during Saturday and Sunday.
That's it! Thank You for viewing...
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