CHAPTER 7 Flashcards
(31 cards)
It is the pores of soil contain both water and air in varying amounts; the water in the upper layers of this zone is called soil moisture.
Zone of aeration
It is the pores of the soils or rock are filled with water; the water in this zone is called groundwater.
Zone of saturation
It is a geologic formation which contains water and transmits it at a rate sufficient to be economically developed for pumping.
Aquifer
It is a geologic formation containing water but transmits it at a rate insufficient to be economically developed for pumping.
Aquiclude
It has a water table serving as the upper surface of the zone of saturation.
Unconfined / water table aquifer
One where the groundwater is confined by a relatively impermeable layer.
Confined or artesian aquifer
It is the upper confining layer is leaky or semi-permeable.
Semi-confined or leaky aquifer
Its lower limit is relatively impermeable layer while its upper surface is a free water surface on water table.
Perched Aquifer
4 types of aquifer:
- Unconfined / Water table aquifer
- Confined or artesian aquifer
- Semi-confined or leaky aquifer
- Perched Aquifer
6 properties of aquifer:
- Porosity
- Specific yield
- Specific retention
- Aquifer conductivity or permeable
- Transmissibility
- Storage coefficient
It is the capacity of formation to contain water.
Porosity
It is the water that can be extracted by gravity flow; measure of the volume of water yield per unit soil volume.
Specific yield
It is the water retained by the soil formation against force of gravity.
Specific retention
It is the measure of the ease with which an aquifer will transmit water; influenced by both the properties of water and aquifer materials.
Aquifer conductivity or permeable
It is the measure of the potential discharge of well penetrating an aquifer, its magnitude is an indication of the economic value of an aquifer as a source of water supply.
Transmissibility
It is the water yielding capacity of confined aquifer.
Storage coefficient
5 threats to groundwater:
- Quantity
- Overdraft
- Drawdown
- Subsidence
- Quality
It is an increased quantity of groundwater is being withdrawn to meet the demands of a growing population.
Quantity
Typical threats that is associated with QUANTITY.
- Overdraft
- Drawndown
- Subsidence
It occurs when groundwater is removed faster that recharge can replace it.
Overdraft
TRUE OR FALSE:
Overdraft can result a permanent loss of a portion of its storage capacity.
True
TRUE OR FALSE:
Overdraft can result a change that can cause water of unusable quality to contaminate good water.
True
It differs significantly from overdraft.
Drawdown
It results in a temporarily lowered water table generally caused by pumping.
Drawdown
