Dr Abe V Rotor
This article is very timely as a guide to water management with the coming dry season. Habagat (rainy season) has just ended, we are now in amihan (dry season). We hope that this lesson will serve the interest of both the followers and viewers of this blog, and the listeners on Paaralang Bayan sa Himpapawid aired 8 to 9 in the evening Monday through Friday on DZRB 738 AM KHz.
1. Monsoon rains generally come in June to October- Habagat. The rest of the year is considered dry. Amihan season occurs during the cool months of October to February. The driest months are March and April. Let us conserve water particularly during the dry season.
O D J F M A M J J A S
Dry Season / Wet Season
2. A region or a particular geographic area may possess a micro-climate of its own, and therefore, a distinct rainfall pattern. Let's be guided by this sub-type of climate in the conservation and utilization of water.
Factors Creating a Sub-type of Climate
• Elevation – The higher the elevation, the cooler is the environment. There is more rainfall and thicker vegetation. Examples: Benguet, Mt. Apo, Kanlaon, Bulusan
• Presence of natural barriers – The Cordillera mountain range separates the Ilocos provinces and the Cagayan Valley into two sub-types of climate. The Sierra Madre mountain range has a similar effect.
• Position and closeness to large bodies of water – Samar and Leyte Islands have three micro-climates owing to the varied conditions brought by the surrounding sea as well as the presence of mountains and a large swamp – the Sab- A Basin.
• Forest cover – The thicker and more extensive the primary forest cover, the higher is the precipitation or rainfall falling in and around the area. Examples: Mt. Makiling, parts of Mindanao, Isabela and Palawan still covered by original forests.
3. In the Philippines our main supply of freshwater comes from
- lakes, swamps and ponds;
- rivers and streams; and
- springs and ground water.
Let's take care of these sources and use them wisely following these guidelines.
A. Lakes (e.g. Laguna de Bay, Paoay Lake, Taal Lake), and swamps (e.g. Liguasan Marsh, Sab-A Basin) are made up of a complex system network of watershed, tributaries and distributaries. Watershed supplies water and maintains stability of a lake or swamp.
Management should be holistic, treating the system on the basis of inter-relationships among its parts.
A pond has similar basic structures although it is generally shallow and intermittent, its system very much simpler and reduced. A swamp, compared to a lake, is a water-logged area, usually a basin, thickly vegetated, rich in organic matter deposits such as muck and peat. Natural reservoirs maintain a desirable amount of ground water for agriculture and domestic use.)
B. Rivers and streams conduct runoff/surface water. Their load can be tapped for future use through impounding, especially those which directly run to the sea and dry up after the rainy season. Great potentials for large supply of freshwater await in our major rivers like the Agno River, Tagum River, Aparri River, Mindanao River, Pampanga River, and Agusan River.
4. An efficient watershed maintains the stability of a water reservoir whether it is natural or man made by
- Providing protection against erosion and siltation,
- Increasing the rate of water absorption and impounding,
- Inducing rainfall, and
- Keeping the surroundings cool and reducing evaporation.
A. Erosion and siltation work in tandem. Silt is carried down by water from eroded areas. Deposition causes clogging of waterways, and the silting of farms. It exacerbates flooding, reducing the life of dams, decreases crop yield.
B. Water absorption and conservation of ground water are enhanced by well-maintained watersheds.
C. A micro-climate is created within efficient watershed areas which is conducive to cloud formation and consequent precipitation. This is mainly the result of increased relative humidity and reduced evaporation.
5. Water supply is enhanced by forests and woodlands (man-made forests) through
- Higher rate of rainfall (tropical rain forest is so-called because rain occurs frequently, if not daily, in and around tropical forests, such as Mt. Makiling.
- Fuller rivers, streams and natural springs,
- Abundant amount of ground water and fuller aquifers.
A. A forest has a multi-storey structure that is very efficient in water conservation, and solar and space utilization. Organic matter built on the forest floor helps conserve water like sponge.
- Emergent tree
- Canopy layers
- Lianas & epiphytes
- Bushes & shrubs
- Ground plants
B. The forest cover conserves water and keeps it underground for future use. It slows down water flow thereby increasing the rate of water absorption. The roots of trees help maintain s desirable water level in the ground and fuller aquifers (underground rivers). All these enhance the life of rivers, streams and natural springs.
6. Water impounding in the tropics is a common practice in agriculture, fisheries, power generation, recreation, industry (e.g water coolant), and for domestic use. Commonly adopted designs are based on these models:
- Dam (e.g. Ambuklao, Binga, Angat, Lamesa, Pantabangan, Chico)
- Pond (e.g. farm pond, communal water impounding projects)
- Terrace (e.g. Banaue rice terraces gravity irrigation) and
- Series of catchments (China’s model)
A. Large water reservoirs are very expensive and require extensive areas. They are characterized by high technology and maintenance requirements. Our major dams are suffering from heavy siltation which have drastically reduced their capacity and life.
B. Ponds are mainly for individual use in small and medium farms. Small communal reservoirs projects are popular in Iloilo and in many parts of the country but many of them are not properly managed. Such projects are designed for cooperative farming. One project in Iloilo has 5-ha reservoir, 100-ha watershed, and a service area of 50 hectares, cultivated by some 30 farmers.
C. Water Impounding on the Banaue rice terraces is a classical example of a very efficient water management system. Rainwater is trapped in each of the hundreds of terraced ricefields which then act as a reservoir until the crop is harvested. Through gravity irrigation system paddy water is regulated. Excess water is conducted to the lower paddies and ultimately to the gorge which serves as the main drain.
- Forest Cover
- Upper terraces
- Lower terraces
D. A series of small catchments built along the length of a river conserves virtually all the water that would otherwise go to waste. This system of water impounding is built on intermittent rivers and streams of certain parts of the People’s Republic of China where the rainy season is short leaving the place dry the rest of the year.
7. Where irrigation water is limited, the principle of comparative advantage should be applied. Considering other things equal, choose the crop that gives the highest level of water utilization and returns on investment.
Economics of water utilization during the dry season:
20,000 cubic meters - water requirement of
1 ha of Rice
3 ha of Corn
5 to 6 ha of Bean
8. In recycling water for farm, industry and domestic use follow the principles governing Nature’s Water Cycle, namely
• Water is transformed into three states of matter – solid, liquid and gas. In the process of transformation, water is separated from other substances and impurities.
Examples: In distilling water, the impurities are left behind. Much of the rain which falls on land comes from clouds formed at sea. The process of desalination follows this principle.
• While water cleans, it has also the inherent power of “cleansing itself”.
Examples: Organic matter settles at the bottom of lakes, leaving the water clear and clean. Similarly after heavy downpour, silt and clay settle down leaving the water clear. Natural springs rarely need the attention of man.
• There are certain biological and physical, including geologic and chemical processes that enhance water recycling.
Examples: Aquatic plants maintain a desirable supply of oxygen in water. In sewage treatment, water passes through a series of tanks/pools until it goes out safe and functional again.
Aquifers are natural underground reservoirs and filters.
9. Water pollution exacerbates water shortage. Let's minimize, if not prevent, the pollution of our water supply by using biodegradable materials.
There are now biodegradable plastics. Coconut oil-based detergents are preferred. So with organic fertilizer over chemical fertilizer. Botanical pesticides leave little or no toxic residue.
• Reducing pollutants
Reduced emission of gases which combine with atmospheric water to form “acid rain”. Clear watershed and waterways from all forms of garbage. Prevent clogging and water-logging as these favor accumulation of wastes and increase the effects of pollution. More strict laws on oil spill.
• Practicing cleanliness and sanitation
Proper garbage disposal. Keep industrial wastes away from water sources. Implement a shanty-free estero program. Impose strict sanitation in public markets, and “talipapa”/ flea markets. Strictly implement anti-pollution laws in factories, homes and motor vehicles.
• Banning dangerous pollutants
Let's uphold the anti-nuclear constitutional provision to prevent radioactive fallout incident. Radioactive wastes must be disposed following international safety standards. Permanently ban the “Dirty Dozen” pesticides. Use only unleaded gasoline. Regulate use and disposal of mercury compounds.
• Planning our community
Residential and industrial zoning. Strictly implement building and housing policies of the National Housing Authority, DPWH, local governments, etc, Ecology village concept, Decongest urban centers and promote rural living.
• Educating the public
National Geographic and Nature-Life TV series, DENR media programs on environment, Kalikasan publications, DA and DOST programs on agro-ecology. Include ecology in the school curriculum on all levels. Ban ads of products which contribute to environmental degradation.
10. As the flow of our rivers gets less, our lakes subside, and ground water sinks deeper, saltwater intrusion increase spoiling our farms, springs and wells, rivers, streams and ponds. Ward off saltwater intrusion by
• Preserving the mangrove forests
Mangroves are frontlines against tides and sea currents. They are natural riprap builders and they moderate the rate of flow and mixing of seawater and freshwater at the estuaries.
• Reforestation of mountains and watersheds
Flash floods are frequent where trees have been cut. Runoff water cuts river banks, makes waterways shallow and at the mouth of rivers mudflats are formed. With reduced flown of rivers, seawater intrudes island and underground. In many parts of the country, intrusion is noted in farms as far as 10 km inland.
• Preventing siltation and pirating of rivers
River banks must be protected with trees. Residential areas must kept away from river banks. Farming along rivers and around bodies of water must be controlled, specially if it contributes to erosion and siltation. Farm chemicals drain into rivers and lakes specially if it rains. Reclaiming and pirating beaches, estuaries, rivers and streams should be strictly prohibited. Major obstructions are illegally constructed fishponds, rest houses and shanties.
• Dredging waterways
Many of the rivers are heavily silted and dredging is necessary. This is specially true in and around big urban centers. Illegal dikes and structures must be removed and strict garbage disposal enforced.
• Regulating the drawing of underground water and the damming of rivers
Water rights regulate the rate of drawing water from the ground and rivers. However, this is not being implemented strictly. Too much withdrawal predisposes saltwater intrusion. Many wells and rivers in summer turn saline.
11. Modern technology has developed new ways of tapping and recycling freshwater by means of
• Towing icebergs,
Icebergs are towed hundreds of miles to countries in need of freshwater.
• Desalination of seawater,
Freshwater is produced from seawater through the principle of distillation. To reduce cost, solar energy has replaced conventional fuel. Israel adopts desalination for its agriculture.
• Cloud seeding and inducing rainfall
Rain-inducing compounds are used by airplanes to seed rain clouds. Technology has increased the efficiency of cloud seeding.
• Bottling spring and mineral water, and
Due to dwindling natural supply of safe freshwater, bottling spring and mineral water has become in the last twenty years a booming industry in large urban centers. A chilled 250-ml spring water sells at 15.oo php on university campuses in Manila.
• Re-processing used water.
Unlike the conventional filtration-aeration-chlorination process, used water is recycled for domestic use through a complex purification process in big cities.
12. Everybody should share in the common responsibility to use and conserve water wisely by means of
• Avoiding wasteful use of water
List down ways to save water. These include such simple means as repairing leaky faucets and pipes, to adopting a systematic program in household management.
• Impounding rain and surface water
Residents in small islands depend largely on rain. Their houses are equipped with special gutters and storage jars to trap and store rainwater.
• Maintaining ecological balance
List down all the ways to help preserve the environment to enhance the adequacy of freshwater supply from wells, rivers, springs, etc. Refer to the foregoing principles.~
El Niño indeed gives each and everyone of us ways by which we can minimize its impact on our lives and on our community. Above all it has a humbling effect on our technology - and our wasteful living. It is the great moderator. It is also the great reminder for us to be always prepared to face the vagaries of our climate, more so natural calamities. ~
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Living with Nature-School on Blog is purely a voluntary effort help conserve the natural environment, and to bring functional literacy to millions who lack access to formal education, and to augment formal learning and experiential knowledge. - Dr Abercio V Rotor
(More lessons are found in avrotornaturalism.blogspot.com)
(More lessons are found in avrotornaturalism.blogspot.com)