Examination with Guaranteed Pass
Solutions 2025-2026 Edition.
describe the major features of the clean water act (eg NPDES) and the safe drinking water act
(eg MCL, MCLG) - Answer MCLG- maximum contaminant level goal- level at which there would
be no adverse effect. Does not take into account cost of technical feasibility.
MCL- maximum contaminant level - can be adverse effects, takes cost etc into account
NPDES - national pollutant discharge elimination system, permitting system under CWA for
nutrients and other toxins from point sources
hydrologic cycle - Answer The hydrologic cycle begins with the evaporation of water from the
surface of the ocean. As moist air is lifted, it cools and water vapor condenses to form clouds.
Moisture is transported around the globe until it returns to the surface as precipitation. Once
the water reaches the ground, one of two processes may occur;
1) some of the water may evaporate back into the atmosphere
2) the water may penetrate the surface and become groundwater.
Groundwater either seeps its way to into the oceans, rivers, and streams, or is released back
into the atmosphere through transpiration.
The balance of water that remains on the earth's surface is runoff, which empties into lakes,
rivers and streams and is carried back to the oceans, where the cycle begins again.
evaporation transpiration --> condensation -->
precipitation -->
infiltration / collection
what percentage is saltwater covering on earth's surface? - Answer 70%
,what percentage of earth's water is brackish? - Answer 1%
What is brackish water? - Answer a mixture of salinity between saltwater and freshwater
found in lakes, seas, estuaries and groundwater
freshwater - Answer Does not contain any saltwater and can be rivers, lakes, streams,ponds,
and wetlands
freshwater frozen - Answer 2/3 of frozen ice sheets / glaciers
some in groundwater too
freshwater available for human use - Answer only 0.3% of total water on earth is readily
accessible for human use
sources of drinking water - Answer -groundwater
-protected runoff water
-surface water
what is groundwater? - Answer groundwater fills the spaces between soil particles and
fractured rock underground
Where is the water table located? - Answer the surface of the zone of saturation
is groundwater contaminated? - Answer -Usually free of contamination—bacteria, viruses,
suspended solids, chemicals
-Can become contaminated through human activity—source protection
Is groundwater a renewable resource? - Answer -It is renewable as long as we don't pump it
out of the ground too quickly, then it becomes non-renewable
-Limited in volume—essentially irreplaceable once depleted
what percentage of the population is US groundwater responsible for? - Answer 50%
, How does a well work? - Answer -a hole in the ground, held open by a pipe (or casing) that
extends to an aquifer
-goes through unsaturated zone into the aquifer (zone of saturation)
how does the water aquifer (saturated zone) form? - Answer through layers of befrock
can there be different levels of groundwater? - Answer yes, it is dependent on the layers of
limestone (rock)
do groundwater recharging rates vary? - Answer yes, water very close to the surface is going
to get more of the rainfall, more of the water that falls on the Earth. And it's going to recharge
more readily than these layers that are down further and further.
what consequences of taking water out of the earth? - Answer recharging rates vary, And so
there are consequences, different consequences to taking water out of different depths of
aquifers, taking it out of what are newer, older, or even what they call ancient water.
groundwater contamination "percolates" - Answer Water infiltrates the soil by moving through
the surface. Percolation is the movement of water through the soil itself. Finally, as the water
percolates into the deeper layers of the soil, it reaches ground water, which is water below the
surface.
groundwater contamination - Answer when substances such as sewage, highway salt,
fertilizers, pesticides, chemicals and other industrial materials are present in the water
Wellhead protection area - Answer A protected surface and subsurface zone surrounding a
well or well field supplying a public water system to keep contaminants from reaching the well
water, land uses must be compatible with the preservation of water quality
Protected run-off: cistern - Answer Historical method of collecting rainwater via capturing
fallen rainwater off of a roof into collection, and then taking collection back into home for use,
using raingutters
(must be kept covered to keep free of virus / bacteria contamination)