Stormwater Management Exam 1 Graded A+
About what portion of the incoming sunlight actually makes it to the earth's surface? -
ANSWER-47% ; depending on lattitude
According to Poiseuille's Law, if I double the radius of a tube and all other parameters
remain the same, by how much do I increase the flow rate? - ANSWER-16x
BOD is a measure of what (not what the abbreviation stands for, but what it means)? -
ANSWER-Biological oxygen demand:
Indicator of water quality problem, more organisms need more O2, measure of organics
in a water system
Describe (no need for values) what is meant by the "solar constant". - ANSWER-at the
edge of the atmosphere radiation is constant
Describe a case in which you might be most interested in the mass transport of your
contaminant. - ANSWER-(TMDL) Total Maximum Daily Load set for a mass base
approach
Describe a case in which you might be most interested in whether your contaminant
level exceeds some threshold value. - ANSWER-A Maximum Concentration Level
(MCL) has been set for dissolved oxygen in a stream
Describe at least 2 problems often experienced when looking at contaminant mass
transport. - ANSWER-How do you know the mass of the stream?
relies on very good flow data
Describe at least 2 problems often experienced when looking for a contaminant
threshold level. - ANSWER-it is the maximum or minimum level of contamination legally
allowed in a stream meaning its already too high to too low
Describe the "Type 2" storm shape. - ANSWER-most of the rainfall is in the middle of
the storm,
shaped like a cell
Describe the contact infiltrometer. - ANSWER-put porous material in contact with soil
surface and supply water at a fixed rate. measure amount that is consumed
Describe the difference between a gaining stream and a losing stream. - ANSWER-
gaining stream gains water, losing stream loses water
Describe the dynamic flooding method of measuring infiltration capacity. - ANSWER-run
water over an inclined surface at a fixed rate and measure the amount of runoff.
subtract runoff from amount of water supplied.
, Describe the parts of a good manual raingage - ANSWER-Collection device-well
defined area, sharp edges, very steep sides, bigger is better
Measurement Device-concentrating tube (graduated cylinder) inside of larger cylinder
with room for overflow
Describe the sprinkler infiltrometer. - ANSWER-apply water via sprinkler at constant rate
over time measure amount supplied and consumed
Describe why stormwater tends to move a lot of contaminants. List at least 3 problems
caused by sediment as a water contaminant. - ANSWER-Most pollutants/contaminants
are on the surface.
1. clogging of streams
2. impact on aquatic environment
3. sediment carries pollutants with it
Do we generally want raingages placed on a pattern or more evenly distributed? Explain
why - ANSWER-randomize to find a fixed pattern; grid to find random effects
Do we get more total annual infiltration by infiltrating the many small storms or the few
larger storms? - ANSWER-small storms
Draw a "typical" infiltration capacity rate curve, also giving titles to the axes. - ANSWER-
y axis=>infiltration rate (i)
x axis=>time (t)
Explain why raingages should generally not be placed on a sideslope, rooftops -
ANSWER-hill and rooftops will cause more wind
Explain why the timing of the water supply is important in estimating infiltration. -
ANSWER-if you collect too early, just going to run off and not measure the curve, too
late and wont get to the curve***It needs to be as close to realistic application as
possible for accurate data
For a tipping bucket raingage, what are the
a) advantages?
b) disadvantages - ANSWER-Advantages: easily made electronic, relatively good
resolution
Disadvantages: poor time resolution @ low intensity, swamping concerns @ high
intensity
For a weighing raingage, what are the
a) advantages?
b) disadvantages - ANSWER-Advantages: gives good, continuous reading
About what portion of the incoming sunlight actually makes it to the earth's surface? -
ANSWER-47% ; depending on lattitude
According to Poiseuille's Law, if I double the radius of a tube and all other parameters
remain the same, by how much do I increase the flow rate? - ANSWER-16x
BOD is a measure of what (not what the abbreviation stands for, but what it means)? -
ANSWER-Biological oxygen demand:
Indicator of water quality problem, more organisms need more O2, measure of organics
in a water system
Describe (no need for values) what is meant by the "solar constant". - ANSWER-at the
edge of the atmosphere radiation is constant
Describe a case in which you might be most interested in the mass transport of your
contaminant. - ANSWER-(TMDL) Total Maximum Daily Load set for a mass base
approach
Describe a case in which you might be most interested in whether your contaminant
level exceeds some threshold value. - ANSWER-A Maximum Concentration Level
(MCL) has been set for dissolved oxygen in a stream
Describe at least 2 problems often experienced when looking at contaminant mass
transport. - ANSWER-How do you know the mass of the stream?
relies on very good flow data
Describe at least 2 problems often experienced when looking for a contaminant
threshold level. - ANSWER-it is the maximum or minimum level of contamination legally
allowed in a stream meaning its already too high to too low
Describe the "Type 2" storm shape. - ANSWER-most of the rainfall is in the middle of
the storm,
shaped like a cell
Describe the contact infiltrometer. - ANSWER-put porous material in contact with soil
surface and supply water at a fixed rate. measure amount that is consumed
Describe the difference between a gaining stream and a losing stream. - ANSWER-
gaining stream gains water, losing stream loses water
Describe the dynamic flooding method of measuring infiltration capacity. - ANSWER-run
water over an inclined surface at a fixed rate and measure the amount of runoff.
subtract runoff from amount of water supplied.
, Describe the parts of a good manual raingage - ANSWER-Collection device-well
defined area, sharp edges, very steep sides, bigger is better
Measurement Device-concentrating tube (graduated cylinder) inside of larger cylinder
with room for overflow
Describe the sprinkler infiltrometer. - ANSWER-apply water via sprinkler at constant rate
over time measure amount supplied and consumed
Describe why stormwater tends to move a lot of contaminants. List at least 3 problems
caused by sediment as a water contaminant. - ANSWER-Most pollutants/contaminants
are on the surface.
1. clogging of streams
2. impact on aquatic environment
3. sediment carries pollutants with it
Do we generally want raingages placed on a pattern or more evenly distributed? Explain
why - ANSWER-randomize to find a fixed pattern; grid to find random effects
Do we get more total annual infiltration by infiltrating the many small storms or the few
larger storms? - ANSWER-small storms
Draw a "typical" infiltration capacity rate curve, also giving titles to the axes. - ANSWER-
y axis=>infiltration rate (i)
x axis=>time (t)
Explain why raingages should generally not be placed on a sideslope, rooftops -
ANSWER-hill and rooftops will cause more wind
Explain why the timing of the water supply is important in estimating infiltration. -
ANSWER-if you collect too early, just going to run off and not measure the curve, too
late and wont get to the curve***It needs to be as close to realistic application as
possible for accurate data
For a tipping bucket raingage, what are the
a) advantages?
b) disadvantages - ANSWER-Advantages: easily made electronic, relatively good
resolution
Disadvantages: poor time resolution @ low intensity, swamping concerns @ high
intensity
For a weighing raingage, what are the
a) advantages?
b) disadvantages - ANSWER-Advantages: gives good, continuous reading
