05. RESOURCES: WATER, SOIL, MINERAL & ROCK, AND ENERGY

• For domestic use, agriculture, and industry, it is important to everyone. But, most of us take for granted the availability of it.

  water availability
• Most of the fresh water is locked up as ice, mainly in the large polar ice caps. Even the ground water beneath continental surfaces is not all fresh.
• Geologically, It is a renewable resource, but local supplies may be inadequate inthe short term.

  water
• has a percentage of total water 97.54%

  oceans
• has a percentage of fresh water 73.9%

  ice
• has a percentage of fresh water 25.7%


  ground water
• has a percentage of unfrozen fresh water 98.4%

  ground water
• involve the ability of rocks or other mineral materials (sediments, soils) to contain fluids and to allow fluids to pass through them.

  Porosity and permeability
• • is the proportion of void space in the material (holes or cracks), unfilled by solid material, within or between individual mineral grains and is a measure of how much fluid the material can store.
  • may be expressed either as a percentage or as an equivalent decimal fraction.
  • The pore spaces may be occupied by gas, liquid, or a combination of the two.

  porosity
• is a measure of how readily fluids pass through the material. It is related to the extent to which pores or cracks are interconnected, and to their size—larger pores have a lower surface-to-volume ratio so there is less frictional drag to slow the fluids down.

  permeability
• of geologic materials are both influenced by the shapes of mineral grains or rock fragments in the material, the range of grain sizes present, and the way in which the grains fit together.

  Porosity and permeability
• 1. saturated zone or phreatic zone
  2. unsaturated zone or vadose zone

  subsurface waters
• • is a volume of rock or soil above the impermeable material that is water-saturated, in which water fills all the accessible pore space.
  • Groundwater is the water in this zone.

  Saturated zone or phreatic zone
• • is rock or soil above the saturated zone in which the pore spaces are filled partly with water, partly with air.
  • The water in unsaturated soil is soil moisture, and is often an important factor in agricultural productivity.


  Unsaturated zone or vadose zone
• is all of the water occupying pore space below the ground surface. This includes ground water, soil moisture, and water in unsaturated rocks.

  Subsurface water
• • is the top surface of the saturated zone, where the saturated zone is not confined by overlying impermeable rocks.
  • is not always below the ground surface.

  water table
• is the processes of infiltration and migration or percolation by which ground water is replaced

  Recharge
• occurs where ground water flows into a stream, escapes at the surface in a spring, or otherwise exits the aquifer.

  Groundwater discharge
• • is a rock that holds enough water and transmits it rapidly enough to be useful as a source of water.
  • Many of the best examples are sandstones or other coarse clastic sedimentary rocks


  aquifer
• • is a rock that may store a considerable quantity of water, but in which water flow is slowed, or retarded; that is, its permeability is low, regardless of its porosity.
  • Shales are common examples.


  aquitard
• was used to describe an extreme aquitard, a rock that is essentially impermeable on a human timescale; but virtually no rock would be impermeable indefinitely, and the term aquiclude has fallen into disuse.

  Aquiclude
• • confined
  • unconfined


  types of aquifer
• • is when the aquifer is directly overlain only by permeable rocks and soil.
  • may be recharged by infiltration over the whole area underlain by that aquifer, if no impermeable layers above to stop the downward flow of water from surface to aquifer.


  Unconfined aquifer
• • is bounded above and below by low permeability rocks (aquitards).
  • Water in this aquifer may be under considerable pressure from the adjacent rocks, or as a consequence of lateral differences in elevation within the aquifer

  confined aquifer
• If a well is drilled into a confined aquifer, the water can rise above its level in the aquifer because of this extra hydrostatic (fluid) pressure.

  artesian system
• represents the height to which the water’s pressure would raise the water if the water were unconfined.

  potentiometric surface
• Natural internal pressure in a confined aquifer system creates artesian conditions, in which water may rise above the apparent (confined) local water table.
• 1. Lowering the Water Table
  2. Compaction and Surface Subsidence
  3. Saltwater Intrusion


  Consequences of Groundwater Withdrawal
• When ground water is pumped out from an aquifer, the rate at which water flows in from surrounding rock to replace the extracted water is generally slower than the rate at which water is taken out.

  Lowering the Water Table
• is a circular lowering of the water table immediately around the well in an unconfined aquifer.

  Cone of depression
• Overlapping Cones of Depression Lead to Net Lowering of the Water Table; Shallower Wells may Run Dry
• If the aquifer rocks are no longer saturated with water, they may become compacted from the weight of overlying rocks. This decreases their porosity, permanently reducing their water-holding capacity, and may also decrease their permeability.

  Compaction and Surface Subsidence
• is an example of surface subsidence due to over-pumping of groundwater by the increasing population (Dinglasan, 2013).

  Metro Manila
• is another problem arising from groundwater use in coastal regions.

  Salt water intrusion
• Once a section of an aquifer becomes tainted with salt, it cannot readily be “made fresh” again.
• may involve extensive modification of surface-water runoff patterns and stream channels. As it modifies surface runoff and the ratio of runoff to infiltration, it also influences groundwater hydrology

  Urbanization
• Impermeable cover such as buildings, asphalt and concrete roads, sidewalks, parking lots, and airport runways over one part of a broad area underlain by an unconfined aquifer has relatively little impact on that aquifer’s recharge.
• the available recharge area may be very limited, since the overlying confining layer prevents direct downward infiltration in most places. If impermeable cover is built over the recharge area of this aquifer, then, recharge can be considerably reduced, thus aggravating the water-supply situation.

  confined aquifer
• is a common way to provide more land for construction. This practice can interfere with recharge, especially if surface runoff is rapid elsewhere in the area.

  Filling in wetlands
• A marsh or swamp in a recharge area that is holding water for long periods can be a major source of infiltration and recharge. Filling it in so water no longer accumulates there and topping the fill with impermeable cover may greatly reduce local groundwater recharge.