STORM TEST 3 QUESTIONS AND ANSWERS
True or false: urban growth trees were found to typically have larger and more effective
canopies for intercepting rainfall than forest grown trees - answer -true
Which type of tree - deciduous or evergreen - was shown to be more effective at rainfall
interception regardless of region? - answer -evergreen
In which region - southeast of pacific northwest - was a higher percentage of
precipitation captured by tree canopies? - answer -pacific northwest
If you were calculating runoff using the rational formula, which variable (c,i, or a) would
best describe the impact of tree canopies on runoff based on the article "give me the
numbers"? - answer -i
What does lid stand for? - answer -low impact development
What two major components make up the lh for a watershed? - answer -overland flow
and channel flow
In the storm water runoff hydrograph, the point at the top of the curve (n) represents: -
answer -peak runoff rate and time of peak
The shaded area beneath the curve on the hydrograph represents: - answer -qvol
The two portions of this stream hydrograph identified at top and bottom of curves
repectively: - answer -base flow; storm flow
True or false: infiltration is the primary hydrologic process supporting stream base flow -
answer -true
True or false: runoff on a slop typically flows downhill perpendicular to the contours -
answer -true
True or false: the rational formula is most appropriate for use in relatively small
watersheds because inherent model error becomes excessive as the watershed are
gets larger - answer -true
Determining qvol is an essential hydrologic modeling practice because it allows the
designer to: - answer -size storage areas appropriately
Why did teague and kuehler's research show that trees in the nw capture and retain
more rainfall than trees in the se? - answer -rainfall events in the nw are less intense
than in se
,A slope of 6% is equivalent to a ratio of: - answer -16.67h:1v
A depression pond is proposed. What is the mose correct point for the at-grade
overflow? - answer -the lowest point within the water limits
In the article "give me the numbers", when comparing comparably sized trees, what
kinds of trees were most effective at capturing and retaining rainfall volume in the
canopy? - answer -conifers
True or false: creating an impervious area on a site will typically increase both qp and
qvol. - answer -false
Along the centerline of a gradually descending roadway, the 426 contour is 135' away
from the 420 contour. The gradient of the road is: - answer -d=l/g
G=l/d
G= 6/135
G=.044 = 4.44%
True or false: the faster the time of concentration, the lower the intensity. - answer -
false
True or false: teague and kuehler's research found that the typical forest frown tree
most commonly has a more effective canopy for rainwater capture than the typical
urban tree - answer -false
A co-worker of yours calculated before-development and after-development site
stormwater runoff using the rational formula and also scs method for an 18-acre
watershed. He carefully followed the procedures you have learned. Based on the
results, which finding is most correct? - answer -both are equally correct even with
different results
The lh for a watershed includes 1,800 feet of a mountain stream. If the channel drops
20 feet over that distance, approximately how long will it take water to travel that
distance (rounding to the nearest minute) - answer -14 mins - use figure 11.4
(nomograph for channel flow time)
True or false: given equal lengths and slope of flow, overland flow is typically faster than
channel flow - answer -false
Both the faa formula for calculating the time of concentration and the scs method for
calculating the time of concentration rely on what criticl information? - answer -slope,
land surface characteristics, lh length
A reasonable minimum slop for reliable draining turf area is: - answer -2%
, A map is drawn at 1:24,000. Which side of a standard engineering scale should you
measure it with? - answer -1 inch = 24000 in
1 inch = 24000/12
1 inch = 2000 ft
20 scale
The modified rational formula "improves" the rational formula by accounting for: -
answer -antecedent precipitation
Which topographic form (swale, ridge, constant) is most likely to exhibit the longest
sheet flow condition? - answer -ridge
When designing a development on a site which currently is undeveloped, and modeling
runoff using the scs method, keeping the first portion of the lh in its existing condition is
important because: - answer -sheet flow accounts for more travel time than shallow
concentrated flow & maintaining a longer time of concentration will minimize increase
runoff due to development
The tc for an athens, ga watershed is 34.3 minutes. What is the intensity (in/hr) for the
50 year event in the watershed? - answer -use table provided
When applying the modified rational formula, why must adjusted c values must not
exceed 1.0? - answer -it represents a percentage of runoff and you cant have over
100%
True or fall: given equal slope and soil conditions, good dense forest usually generates
less runoff than good dense turf grass. - answer -true
Based on the following watershed information, what is the peak rate of runoff? - answer
-qp= cia
=.37(34.23)(4.49)
=56.87
True or false: based on our class discussions, qd is understod to be the runoff depth. -
answer -true
True or false: when comparing watersheds in the same geographic setting using the scs
method, the major factor influencing qvol is cn - answer -true
A storm event is calculated to produce 1.00 acre-feet of runoff from a 4.7 acre
watershed. What is the equivalent volume in cubic feet? - answer -43,560 cf
Which of the following stormwater management practices controls both qp and qvol? -
answer -infiltration
True or false: urban growth trees were found to typically have larger and more effective
canopies for intercepting rainfall than forest grown trees - answer -true
Which type of tree - deciduous or evergreen - was shown to be more effective at rainfall
interception regardless of region? - answer -evergreen
In which region - southeast of pacific northwest - was a higher percentage of
precipitation captured by tree canopies? - answer -pacific northwest
If you were calculating runoff using the rational formula, which variable (c,i, or a) would
best describe the impact of tree canopies on runoff based on the article "give me the
numbers"? - answer -i
What does lid stand for? - answer -low impact development
What two major components make up the lh for a watershed? - answer -overland flow
and channel flow
In the storm water runoff hydrograph, the point at the top of the curve (n) represents: -
answer -peak runoff rate and time of peak
The shaded area beneath the curve on the hydrograph represents: - answer -qvol
The two portions of this stream hydrograph identified at top and bottom of curves
repectively: - answer -base flow; storm flow
True or false: infiltration is the primary hydrologic process supporting stream base flow -
answer -true
True or false: runoff on a slop typically flows downhill perpendicular to the contours -
answer -true
True or false: the rational formula is most appropriate for use in relatively small
watersheds because inherent model error becomes excessive as the watershed are
gets larger - answer -true
Determining qvol is an essential hydrologic modeling practice because it allows the
designer to: - answer -size storage areas appropriately
Why did teague and kuehler's research show that trees in the nw capture and retain
more rainfall than trees in the se? - answer -rainfall events in the nw are less intense
than in se
,A slope of 6% is equivalent to a ratio of: - answer -16.67h:1v
A depression pond is proposed. What is the mose correct point for the at-grade
overflow? - answer -the lowest point within the water limits
In the article "give me the numbers", when comparing comparably sized trees, what
kinds of trees were most effective at capturing and retaining rainfall volume in the
canopy? - answer -conifers
True or false: creating an impervious area on a site will typically increase both qp and
qvol. - answer -false
Along the centerline of a gradually descending roadway, the 426 contour is 135' away
from the 420 contour. The gradient of the road is: - answer -d=l/g
G=l/d
G= 6/135
G=.044 = 4.44%
True or false: the faster the time of concentration, the lower the intensity. - answer -
false
True or false: teague and kuehler's research found that the typical forest frown tree
most commonly has a more effective canopy for rainwater capture than the typical
urban tree - answer -false
A co-worker of yours calculated before-development and after-development site
stormwater runoff using the rational formula and also scs method for an 18-acre
watershed. He carefully followed the procedures you have learned. Based on the
results, which finding is most correct? - answer -both are equally correct even with
different results
The lh for a watershed includes 1,800 feet of a mountain stream. If the channel drops
20 feet over that distance, approximately how long will it take water to travel that
distance (rounding to the nearest minute) - answer -14 mins - use figure 11.4
(nomograph for channel flow time)
True or false: given equal lengths and slope of flow, overland flow is typically faster than
channel flow - answer -false
Both the faa formula for calculating the time of concentration and the scs method for
calculating the time of concentration rely on what criticl information? - answer -slope,
land surface characteristics, lh length
A reasonable minimum slop for reliable draining turf area is: - answer -2%
, A map is drawn at 1:24,000. Which side of a standard engineering scale should you
measure it with? - answer -1 inch = 24000 in
1 inch = 24000/12
1 inch = 2000 ft
20 scale
The modified rational formula "improves" the rational formula by accounting for: -
answer -antecedent precipitation
Which topographic form (swale, ridge, constant) is most likely to exhibit the longest
sheet flow condition? - answer -ridge
When designing a development on a site which currently is undeveloped, and modeling
runoff using the scs method, keeping the first portion of the lh in its existing condition is
important because: - answer -sheet flow accounts for more travel time than shallow
concentrated flow & maintaining a longer time of concentration will minimize increase
runoff due to development
The tc for an athens, ga watershed is 34.3 minutes. What is the intensity (in/hr) for the
50 year event in the watershed? - answer -use table provided
When applying the modified rational formula, why must adjusted c values must not
exceed 1.0? - answer -it represents a percentage of runoff and you cant have over
100%
True or fall: given equal slope and soil conditions, good dense forest usually generates
less runoff than good dense turf grass. - answer -true
Based on the following watershed information, what is the peak rate of runoff? - answer
-qp= cia
=.37(34.23)(4.49)
=56.87
True or false: based on our class discussions, qd is understod to be the runoff depth. -
answer -true
True or false: when comparing watersheds in the same geographic setting using the scs
method, the major factor influencing qvol is cn - answer -true
A storm event is calculated to produce 1.00 acre-feet of runoff from a 4.7 acre
watershed. What is the equivalent volume in cubic feet? - answer -43,560 cf
Which of the following stormwater management practices controls both qp and qvol? -
answer -infiltration
