Land and Water Conservation Engineering

Land and Water Conservation Engineering

• Land and Water Conservation Engineering is the use of engineering and biological principles to solve soil and water management problems.
• Conservation means using resources without waste, maintaining high crop production, and enhancing environmental quality.

Engineering Problems in Soil and Water Conservation

• Erosion control is a key aspect of soil and water conservation
• Drainage systems are engineered to manage excess water
• Irrigation systems are designed for efficient water distribution to crops
• Flood control measures are implemented to mitigate flood damage
• Water resources development and conservation strategies are essential

Engineers in Land and Water Conservation

• Soil and water conservation requires integration of engineering, atmospheric, plant, and soil sciences through agricultural and biosystems engineers.
• Soil physical, chemical, and engineering characteristics are crucial considerations.
• Understanding soil-plant-water-environment interactions is key.
• Optimizing the environment for plant and animal production is a goal.
• Managing rural-urban interfaces, air and water pollution is necessary for soil and water conservation.
• Socio-economic aspects, government policies, laws, and regulations impact conservation efforts.
• Ground and satellite mapping techniques (GIS), weather records, soil surveys, computers, numerical simulations (modeling) are important.

Conservation Ethics

• Conserving land and water resources becomes more critical with increasing population.
• A decreasing wildlife population, species extinction, air and water pollution, and habitat loss all affect conservation ethics.
• Soil erosion is a major cause of water pollution.
• Prime farmlands are being converted to urban development.
• Natural resources should be passed on in good or better condition to future generations.
• Increased trends in conservation, including government incentives and private sector-led initiatives, provide short and long-term economic benefits
• Recycling paper, glass, and metals is important for conservation
• Waste segregation and plastic bans are important for environmental health
• Increasing costs of waste disposal highlights the need for better waste management

Soil Erosion Control

• Soil erosion is mainly caused by human exploitation of natural resources and removal of plants.
• Urban-rural interface challenges include high population density, increased runoff, and changes in land use.
• Erosion control is needed to keep crops productive and prevent sedimentation and pollution of waterways.
• Nature takes many years to build topsoil, which can be lost quickly due to misuse.
• Soil erosion is affected by: climate (rainfall regime), soil type, plant cover, topography (slope), and conservation practice

Irrigation and Drainage

• Irrigation and drainage involve managing water to improve plant growth.
• Drainage is the improvement of the land and includes leaching, reclaiming saline or sodic soils, maintaining low water tables.
• Irrigation is used to increase crop production, germination, control air temperature and improve applying chemicals.
• Reservoirs are developed to store water in times and places where it is not available.
• Cropping intensity and intensification can be increased.
• Groundwater extraction and recharge is often used in areas with land subsidence

Flood Control

• Floods lead to loss of life, crops, and property, and disrupts services.
• There will be increased flood loses in the future because of continuous development and unpredictable weather.
• Flood control prevents overland flow in lowlands and reduces flow in streams during and after heavy storms.

Water Resources Development and Conservation

• Agriculture uses 70% of total water
• About 40 % of water used in irrigation cannot be used for crops.
• Percolation, seepage, conveyance, and evaporation are considered losses.
• It is key to eliminate / reduce losses and improve efficiency
• Groundwater recharge and water harvesting techniques are key
• In water-short areas, modified tillage, level terracing, contouring, reservoirs and other conservation methods are important

Land and Water Resource Profiles of the Philippines

• The total land area is 30 M has
  • 14.2 M has are alienable and disposable
  • 15.8 M has are forrests
  • 10.3 M has are agricultural land
• Irrigated area: 3.1 M has
• PD 1067, The Water Code of the Philippines: All waters belong to the State
• Rainfall
  • The mean rainfall is 2,030 mm
  • Rainfall range: 965 to 4,064 mm

Land and Water Resources in the Philippines

• There are 421 rivers in the Philippines including:
  • Cagayan River Basin (25, 649 km²)
  • Mindanao River Basin (23,169 km²)
  • Agusan River Basin (10, 921 km²)
  • Pampanga River Basin (9, 759 km²)
  • Agno River Basin (5, 952 km²)
• The Philippines has 79 natural lakes and more than 100,000 has of freshwater swamps including:
  • Laguna de Bay (90,000 has)
  • Lake Lanao (34,700 has)
  • Lake Taal (23,356 has)
  • Candaba swamp (32,000 has)
  • Agusan marshland (86,359 has)
  • Liguasan/Libungan Marshland (280,000 has)
• There are 7 large and 54 small dams in the Philippines, which have a total capacity of 80 M m³
  • A dam is considered to be large when the storage capacity exceeds 50 M m³ and the hight is more than 30 m

Dams in the Philippines

• Rock-fill dam; spilling level ~ 219 m
• Located in San Lorenzo, Norzaragay, Bulacan
• Storage capacity ~ 850 M m³
• Irrigation provided to ~ 31,000 has in 20 towns in Pampanga and Bulacan.
• Provides industrial water to Metro Manila
• Creates hydroelectric water to the Luzon grid
• Decreases flooding for downstream towns and villages
• Drainage area ~ 568 km²
• Average rainfall ~ 4,200 mm

Ambuklao Hydroelectric

• The dam is 36 km NE of Baguio City, Bokod, Benguet
• It provides the Luzon grid with MW of energy of 75
• The Agno River is being utilized (longest waterway in Luzon)
• The dam measures 129m hight and 452 m in length, 758 m crest elevation
• Gross storage capacity of the reservoir: 327.170 M m³
• Usable storage capacity of the reservoir: 258 M m³
• Drainage area of 686 km²
• 11 km long and 1 km max width

Pulangi IV

• Located in Maramag, Bukidnon
• Watershed with a 1.8 M has
• 255 MW capacity
• Irrigates ~ 8,000
• 1,985 has pond area
• Reservoir capacity of 67 M m³

Magat Dam: Magat River Integrated Irrigation System (MARIIS)

• Located on Magat River, between Alfonso Lista, Ifugao and Ramon, Isabela
• Large rock-fill dam constructed in 1983
• Used to provide irrigation water for ~ 85,000 has of agricultural lands
• Provides hydroelectric power with a rated capacity of 360 W
• 117 km² reservoir with a normal level of 178.3 m and a maximum of 193 m
• 412,000 has watershed area
• Storage capacity of ~ 1.08 B m³

Pantabangan Dam: Upper Pampanga River Integrated Irrigation System (UPRIIS)

• Located in Pantabangan, Nueva Ecija
• One of the biggest in Asia, with storage capacity of ~ 3 B m³
• The dam used to provide irrigation to ~ 106,400 has ricelands
• Power generation on the dam generates 100 MW
• Flood control of the dam is designed for ~ 330 M m³
• Zoned earth-fill with vertical impervious core
• Weak conglomerate, cemented sandstones, siltstone and shales structure the dam
• Main embankment across Pampanga River and an auxiliary dam across Aya Creek with a saddle dam connecting both

La Mesa Dam

• Located in Novaliches, Quezon City
• Earth dam first erected in 1929
• It was raised in 1959 to a max storage capacity of 50.5 M m³
• Overflow level is at an elevation of 80.15 m
• Watershed area ~ 27 km²
• Average rainfall of 2,000 mm

San Roque Dam: San Roque Multipurpose Project

• Located in San Manuel and San Nicolas Pangasinan
• The dam has a gated spillway, 200-m high and 1.2-km long embankment dam on the Agno River
• ~ 12.8 km² reservoir surface area extends North into the municipality of Itogon, Benguet
• A gated spillway protects the drainage basin dam overtopping at 1,225 km²
• The SRMP started commercial use on May 1, 2003
• Rated capacity of 345 MW is installed
• Provides sustainable irrigation to 12,000 has in Pangasinan which can be extended to 34,500 has once project is completed
• ARIIP involves the rehabilitation and construction of irrigation and drainage facilities of the Agno River Irrigation System (ADRIS)
  • ARIS benefits the municipalities of Mapandan, Sta. Barbara, Calasiao, Laoac, Mangaldan, Manaoag, Binalonan, Urdaneta, Yillaaasis, Asingan and San Manuel
  • ADRIS services Natividad, San Nicolas, San Quitin, Sta. Maria, Tayug and Balungao

Small Water Impounding Projects (SWIPS)

• Constructed across a narrow depression or valley.
• Holds back water and develops a reservoir.
• Stores rainfall and runoff during the rainy season for future use.
• Has 318 units, with a service area of 18,159 (BSWM)
• Small Farm Reservoirs (SFRs) – no data.

Ground Water Resources

• Shallow Well Areas: 5.1764 M has
• Deep Well Areas: 12.3023 M has
• Difficult Areas: 12.2534 M has

The need for Soil and Water Conservation

• The size and resources of the Philippines remain constant.
• Land and water resources support a population growing at a rate of ~ 0.816%, estimated at ~ 115.56 million as of 2022.
• Natural Resources are strained by our wants and needs
• Environmental disasters have shown Filipinos the value of water and land sources

Land and Water Resources Degradation

• 623 M metric tons over 28 M has in were estimated in 1990
• Erosion affected ~ 45% of the total land area of the country
  • 17% under severe erosion, the rest moderately affected
• By region, CAR is most affected; 63% followed by Region 10 at 54%; Region 3 is least affected at 26%
• ~339 M metric tons of soil were eroded in 1988
• 342 M metric tons of eroded soil were eroded in 1993
• Sediment from farming ~67 to 68 M tons per year
• ~194,000 tons of nitrogen, 40,000 tons of phosphorous and 30,000 tons of potassium where annual average nutrient loss in fertilizer equivalent
• Use of water is rapidly increasing from domestic sector, industry and agriculture
• Sustainability of heavy pollution load, climatic changes and related ecosystems are threatened on health of people
• 97 of 251 rivers belonged to class A1 (1997)
• ~30% of class A rivers were found in Region X as of 1997, NWRB granted 14,432 water rights
• 4,704,112 Ips total abstraction rate
• – 1,434,597 irrigated lands (Dec 2004)
• 1,327 with 612.95 M m³ total production per year serves 27% of the population (LWUA, 1997)

Allocation

• Allocation includes competing land uses and massive and indiscriminate conversions that threaten agriculture lands
• There is an increased demand from natural phenomena like volcanic eruptions, earthquakes and typhoons
• Since 1991, 10M has have been devoted to agricultural use. This is ~34% of total land area

Data Availibility

• Effective water management and regulation is limited due to missing ecological data
• Limited historical data; most are projects or special studies and some are only projections
• Information is available in different agencies but needs to be organized for better use.

Qualitative effects of soil erosion

• These effects are for onsite an offsite qualitative assessments of erosion with its effect of on:
  • Sedimentation
  • Water resource quality
  • Water resource quantity
  • Water degradation