unit 5

103. wells


Def – a shaft sunk into the ground to obtain water, oil, or gas.

Sen – i went to well to get some water

Ex – 1. In the Fairytales the princess always gets water from the well

2. They use to get water From the wells 


104. Aquifer Depletion
Def – Groundwater depletion, a term often defined as long-term water-level declines caused by sustained groundwater pumping, is a key issue associated with groundwater use.

Sen – 

105. Salt Water Intrusion


def- is the movement of saline water into freshwater aquifers, which can lead to contamination of drinking water sources and other consequences.



Such a saltwater saucer of fresh water is maintained full to overflowing by the rainfall, and owing to the frictional resistance of the sand and to capillary action and the fact that a given column of fresh water is balanced by a shorter column of sea water, the fresh water never sinks to the mean sea-level unless artificially abstracted.



106. dams
Def – A barrier against the passage of liquid or loose material, as a rubber sheet used in dentistry to isolate one or more teeth from the rest of the mouth.

Sen – He tried to damhisgrief.


107. Dam Removal
Def –  is the process of removing out-dated, dangerous, or ecologically damaging dams from river systems. There are thousands of out-dated dams in the United States that were built in the 18th and 19th centuries, as well as many more recent ones that have caused such great ecological damage, that they are proposed for removal.

Sen – He received his earlier education in his native city, until the removal of his family in 18c8 to Boston.

108. Agriculture effects on freshwater
Def – Due to inappropriate water management and irrigation technology, water run-off from fields to adjacent rivers, wetlands and lakes is common. This run-off, however, does not only contain soil sediments but also pesticide residues, salts and fertilisers.

Sen – The region contains most of the country’s rain-fed agriculture.

109. Recreational effects on freshwater
Def – are sources ofwater that are useful or potentially useful. Uses of water includeagricultural,industrial,household,recreational andenvironmentalactivities. 

Sen – Several of the marine and many species of freshwater algae are peculiar to the island.

110Non-point source pollution

Def – Nonpoint source pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage or hydrologic modification. Nonpoint source (NPS) pollution, unlike pollution from industrial and sewage treatment plants, comes from many diffuse sources.

Sen – 

111.Point source pollution

def – is a single identifiable source of airWater pollution,thermalnoise or light pollution.

Sen – Water pollution coming from a single point, such as a sewage-outflow pipe

112.Primary waste water treatment
Def – is the process of removingcontaminantsfrom wastewater, primarily from householdsewage

Sen – The wastewater reclamation pond has a certain odor to it. 


113. Secondary waste water treatment
Def – is a treatment process for wastewater (or sewage) to achieve a certain degree of effluent quality by using a sewage treatment plantwith physical phase separation to remove settleable solids and a biological process to remove dissolved and suspended organic compounds

Sen – 

114. Tertiary waste water treatment
Def – 

Sen –