BRAE 340- Exam 1 questions well
answered already passed
Statements (1) and (2) refer to water requirements. Are these Net or Gross requirements?
(1) The pump withdraws water from the reservoir at the rate of 800 gallons per minute.
(2) Walnut trees can use up to 85 gallons of water per day. - correct answer ✔✔(1) refers to the
Pump or System => this is a Gross amount
(2) refers to the Crop => this s a Net amount
The correct answer is: (1) is Gross; (2) is Net
Statements (1) and (2) refer to water volumes. Are these Net or Gross volumes?
(1) Crop water use (cu-ft) = Seasonal ET (ft) x Crop area (acres) x 43,560 sq-ft/acre
(2) Volume applied by system (ac-in) = Application rate (in/hr) x Irrigation time (hr) x Area
(acres) - correct answer ✔✔(1) is Net; (2) is Gross
An irrigation system applies a gross amount of 41 inches of water during the growing season. An
evaluation determines that: 29 inches goes to satify crop ET; 8 inches runs off and is not
collected for reuse; 3 inches passes through the root zone as deep percolation (total), of which
3 inches are beneficial leaching for salt removal; and 1 inch is ET from weeds. What is the
irrigation efficiency (%)? - correct answer ✔✔Benefical Uses (inches) = Crop ET + Crop Cooling +
Leaching
,IE (%) = Benficial IW (in) ÷ Total Applied (in) * 100
The correct answer is: 78.0%
ET, or evapotranspiration, is best described by which of the following? - correct answer ✔✔The
sum of plant transpiration and water evaporated from wet plant or soil surfaces.
Which one of the following is NOT a reason why irrigation in the west usually requires leaching?
- correct answer ✔✔Since all irrigation water contains some salt, continued irrigation adds
more and more salt to the soil. Plants take up water, but leave the salts behind. So excess water
must be applied to wash the salts below the root zone. This process is called leaching. The
addition of chemicals will not remove the salt.
The correct answer is: Chemical leaching with soil amendments like gypsum eliminates salt
problems and saves water.
If it takes 2779 gallons of water to grow the food for a family of 4 people for one day, how many
million acre-feet (MAF) of water would it take to feed a population of 39.7 million people for 1
year? - correct answer ✔✔gallons/day/family x 1 family/population = gal/person/day
gal/person/day x 365 days/year = gal/yr x 1 cu-ft/7.48 gal = cu-ft/yr
cu-ft/yr x 1 acre/43,560 sq-ft = ac-ft/yr
ac-ft/yr x million people = MAF
The correct answer is: 30.9 MAF
, A city of 819622 people use 283 gallons of water per person per day. What is the city's water
use in acre-feet per year? - correct answer ✔✔people x gal/person/day = gal/day
gal/day x 1 cu-ft/7.48 gal = cu-ft/day
cu-ft/day x 1 acre/43560 sq-ft = ac-ft/day
ac-ft/day x 365 days/year = ac-ft/yr
The correct answer is: 259838.5
443893 gallons of water are added to a reservoir (with straight sides) covering 2.7 acres. How
many inches does the water level rise after the water is added? - correct answer ✔✔gallons ÷
7.48 gal/cu-ft = cu-ft
cu-ft ÷ acres ÷ 43560 sq-ft/acre = ft
ft x 12 in/ft = inches
The correct answer is: 6.1
A metric sprinkler catalog shows a sprinkler that delivers 0.48 liters/sec (Lps) at an operating
pressure of 98 feet of head. What is the sprinkler flow rate in gallons per minute (gpm)? -
correct answer ✔✔Lps x 15.85 gpm/Lps
The correct answer is: 7.6
answered already passed
Statements (1) and (2) refer to water requirements. Are these Net or Gross requirements?
(1) The pump withdraws water from the reservoir at the rate of 800 gallons per minute.
(2) Walnut trees can use up to 85 gallons of water per day. - correct answer ✔✔(1) refers to the
Pump or System => this is a Gross amount
(2) refers to the Crop => this s a Net amount
The correct answer is: (1) is Gross; (2) is Net
Statements (1) and (2) refer to water volumes. Are these Net or Gross volumes?
(1) Crop water use (cu-ft) = Seasonal ET (ft) x Crop area (acres) x 43,560 sq-ft/acre
(2) Volume applied by system (ac-in) = Application rate (in/hr) x Irrigation time (hr) x Area
(acres) - correct answer ✔✔(1) is Net; (2) is Gross
An irrigation system applies a gross amount of 41 inches of water during the growing season. An
evaluation determines that: 29 inches goes to satify crop ET; 8 inches runs off and is not
collected for reuse; 3 inches passes through the root zone as deep percolation (total), of which
3 inches are beneficial leaching for salt removal; and 1 inch is ET from weeds. What is the
irrigation efficiency (%)? - correct answer ✔✔Benefical Uses (inches) = Crop ET + Crop Cooling +
Leaching
,IE (%) = Benficial IW (in) ÷ Total Applied (in) * 100
The correct answer is: 78.0%
ET, or evapotranspiration, is best described by which of the following? - correct answer ✔✔The
sum of plant transpiration and water evaporated from wet plant or soil surfaces.
Which one of the following is NOT a reason why irrigation in the west usually requires leaching?
- correct answer ✔✔Since all irrigation water contains some salt, continued irrigation adds
more and more salt to the soil. Plants take up water, but leave the salts behind. So excess water
must be applied to wash the salts below the root zone. This process is called leaching. The
addition of chemicals will not remove the salt.
The correct answer is: Chemical leaching with soil amendments like gypsum eliminates salt
problems and saves water.
If it takes 2779 gallons of water to grow the food for a family of 4 people for one day, how many
million acre-feet (MAF) of water would it take to feed a population of 39.7 million people for 1
year? - correct answer ✔✔gallons/day/family x 1 family/population = gal/person/day
gal/person/day x 365 days/year = gal/yr x 1 cu-ft/7.48 gal = cu-ft/yr
cu-ft/yr x 1 acre/43,560 sq-ft = ac-ft/yr
ac-ft/yr x million people = MAF
The correct answer is: 30.9 MAF
, A city of 819622 people use 283 gallons of water per person per day. What is the city's water
use in acre-feet per year? - correct answer ✔✔people x gal/person/day = gal/day
gal/day x 1 cu-ft/7.48 gal = cu-ft/day
cu-ft/day x 1 acre/43560 sq-ft = ac-ft/day
ac-ft/day x 365 days/year = ac-ft/yr
The correct answer is: 259838.5
443893 gallons of water are added to a reservoir (with straight sides) covering 2.7 acres. How
many inches does the water level rise after the water is added? - correct answer ✔✔gallons ÷
7.48 gal/cu-ft = cu-ft
cu-ft ÷ acres ÷ 43560 sq-ft/acre = ft
ft x 12 in/ft = inches
The correct answer is: 6.1
A metric sprinkler catalog shows a sprinkler that delivers 0.48 liters/sec (Lps) at an operating
pressure of 98 feet of head. What is the sprinkler flow rate in gallons per minute (gpm)? -
correct answer ✔✔Lps x 15.85 gpm/Lps
The correct answer is: 7.6
