Group 3

100問 • 10ヶ月前

問題一覧

Vulnerability or susceptibility of the soil to erosion. It is a function of both the physical properties of the soil and land management practices.

Erodibility

A horizontal fully flowing 4 in pipe is discharging water. The x and y- coordinate of the water trajectory measured from the end of the pipe are 1.5 m and 0.8 m, respectively. Assuming that the coefficient of discharge is 1.0, what is the discharge of the pipe?

30 lps

It is the simplest piece of overhead irrigation equipment and is commonly used in small-scale upland farming.

Watering can

An imaginary line of constant elevation on the surface of the ground.

Contour line

What should be the minimum weir height for measuring a flow of 1000 gpm with a 90 degree V-notch weir, if the flow is now moving at 5 ft/sec in a 2 ft wide rectangular channel?

1.2 ft

The peak runoff in an 80 ha (A) watershed corresponding to a rainfall intensity of 20 mm/hr (I) and a runoff coefficient of 0.7 (C) is.

3.1m3/s

The process of covering the land surface with plant residues, plastic or other materials appropriate to arrest loss of moisture through evaporation

Mulching

A 10 inch diameter pipe is flowing 1/3 full, what is the velocity of the water if the volume of flow is 135 gpm?

2.0 ft/sec

The ratio of the volume of water to the total soil volume

Volume basis or volumetric MC

The Scientific name for onion:

Allium sepa

On a 20% hill slope, it is proposed to construct bench terraces with 1.1batter slope. If the vertical interval is 2 m, what is the width of the terrace?

8 m

A major irrigation system managed by the national irrigation administration

National irrigation system

1250 cu.m of water was delivered to a 10 ha farm for the month of June in which the consumptive use is estimated at 8 mm/day. The effective rainfall for the period was 150 mm. What is the irrigation frequency?

72%

Evapotranspiration in an 8 ha farm is 7 mm/day and percolation losses is 2 mm/day. What is the design discharge of a canal to be able to deliver a 5 day requirement of the farm in 24 hours, if irrigation efficiency is 75%?

200 cu.m/hr

Expresses the relationship between speed in rpm, discharge in gpm, and head in feet.

Specific speed

What is the depth of water in a trapezoidal channel with a side slope of 2 and carrying a 2.5 cu.m/s water flow? The channel bottom width is 1.5 m and the flowing water has a velocity of 0.8 m/s.

0.93 m

Provide record of the highest stage observed at a stream

Crest stage gage

An association of farmers within a contiguous area served by a national irrigation system or communal irrigation system

Irrigators’ Association

How many sprinklers with spacing of 7m x 7m are needed to irrigate a rectangular piece of land 125m x 190m if the laterals are set parallels to the longer side of the field.

486

Given the following direct runoff hydrograph in m3/s taken at 1 hr interval in the mainstream of a 50sq.km watershed:0, 2.8, 13.8, 44.8, 77.8, 37.8, 12.8, 4.5, 1.8, 1.3, 0.9, 0.6, 0.2. The equivalent depth of direct runoff is.

14.3 mm

The ratio between the water delivered to the farm and the water diverted from a river or reservoir expressed in percent

Water conveyance efficiency

Consists of carrying out agricultural operations very nearly on the contour. It reduces the velocity of overland flow and retards soil erosion

Contour cultivation

If the impeller speed of a centrifugal pump is increased from 1800 rpm to2340 rpm, the resulting power will be how many times the original?

2197

Is a graphical representation of the instantaneous runoff rate against time. The area under the hydrograph gives the runoff volume

Hydrograph

One liter per second is equal to

15.85 gpm

An irrigation system that is managed by a bonafide irrigators association.

Communal irrigation system

Record the pressure required to maintain a small flow of gas from an orifice submerged in the stream

Bubbler gage

A soil sample was obtained using a cylindrical soil sampler with a 4 inches diameter and 10 inches height. After oven drying the sample weight is 2470 g, what is the soil bulk density?

1200 kg/cu.m

A soil sample was obtained using a cylindrical soil sampler with a 4 inches diameter and 10 inches height. After oven drying the sample weight is 2470 g, compute the wetted perimeter.

1.63 m

A soil sample was obtained using a cylindrical soil sampler with a 4 inches diameter and 10 inches height. After oven drying the sample weight is 2470 g, the hydraulic radius is?

0.22 m

A soil sample was obtained using a cylindrical soil sampler with a 4 inches diameter and 10 inches height. After oven drying the sample weight is 2470 g, the velocity of the flow is?

0.58 m/s

A soil sample was obtained using a cylindrical soil sampler with a 4 inches diameter and 10 inches height. After oven drying the sample weight is 2470 g, what is the discharge in li/sec?

209 li/sec

A dam spillway is to be designed to have a service life of 50 years. If the acceptable risk for structural failure due to excessive flood discharge is 10%, the spillway should be designed for a return period of.

475 years

Planting different crops simultaneously in the same field at the same cropping season.

Multi cropping or mixed cropping

An irrigation engineer is to irrigate a crop planted in furrows of 100m x 100m area. The inflow rate is 0.5 li/sec/100m. If the furrow spacing is 50 cm and the application depth is 100 mm, determine the time in hours to irrigate the whole area.

555.6 hrs

Discharge is not constant with respect to time

Unsteady flow

2.78 hrs/furrow

The lateral flow of liquid through porous media; the loss of water from irrigation canals.

Seepage

Find the irrigation interval. Given the ff. WHC- 1.5; MAD- 50%; allowed depletion-0.75 cm; ET/Ea-2.22 mm/day

3 days

The discharge in a 6.56ft wide trapezoidal open channel with a side slope of 1:1 and a bottom slope of 0.1% is 98.8 ft3/s when the depth of flow is 1.0m.The roughness coefficient is.

0.025

A term adapted to measures utilizing both or in combination with the biological and engineering measures.

Vengineering

Establishment of natural waterways or construction of canals and planting it with grasses to make it stable and arrest soil erosion

Grassed waterways

Landslides and slips due to saturation of steep hills and slopes.

Slip erosions

A floating object travelled a distance of 10m in 9.5 seconds on the average in a 0.5m deep parabolic channel. If the top width is 1.0m the discharge is.

0.3m3/s

The peak runoff in the mainstream of a watershed has a mean of 128 m3/s and a standard deviation of 52 m3/s. If the sample data is normally distributed, the magnitude of runoff corresponding to a probability of exceedance of 16% is

180 m3/s

The scientific name for sheep:

Ovis aries

Moisture content present in the soil when gravitational water has been removed is called:

field capacity

A culvert has been designed for a flood discharge with a return period of 50 years. The risk that the culvert will experience the design flood one or more times in 75 years is

78%

75% of available moisture is called:

readily available moisture

The following infiltration capacity equation has been derived based on experimental data: f = 10 + 5e-12t where f is in mm/hr and t is in hr. The cumulative infiltration in mm after 45 minutes is

7.9 mm

The water right based on the concept first time, first in right:

Appropriation Act

The volume of water that can be stored in or released from an aquifer per unit horizontal area per unit change in hydraulic head is

storage coefficient

The lateral movement of water in the soil:

seepage

The velocities at depths of 0.16m and 0.64m in a 0.8m deep and 1.0m wide rectangular open channel are 1.2m/s and 0.3m/s, respectively. The discharge is.

0.6m3/s

The discharge through a 90 v-notch weir may be computed by:

Q = 0.0138H5/2

A fully penetrating well installed in a confined aquifer with a transmissivity of 197 m2/day is pumped at a constant rate. If the drawdowns in two observation wells 8 m and 22 m from the pumped well were observed to be 1.42 m and 0.44 m, respectively, the steady state pump discharge is

220 gpm

Development of deep well by compressed air is best suited for ___wells.

small

The velocities at 0.2 and 0.8 of the depth of flow in a parabolic open channel are 1.0 m/s and 0. 2 m/s, respectively. If the flow depth is 0.5 m and the top width is 1.5 m, the discharge is

300 lps

The mass per unit volume of the soil particles is:

soil density

The ratio of the volume of pores to the volume of solid is:

void ratio

Given the following direct runoff hydrograph in m3/s taken at 1-hr interval in the mainstream of a 50 sq. km watershed: 0, 2.8, 13.8, 44.8, 77.8, 37.8, 12.8, 4.5, 1.8, 1.3, 0.9, 0.6, 0.2. The equivalent depth of direct runoff is

14.3 mm

Water held by forces of surface tension and continuous films around the soil particles is:

capillary water

A fully penetrating well installed in a confined aquifer with a transmissivity of 197m2/day is pumped at a constant rate. If the drawdowns in two observation wells 8m and 22m from the pumped well were observed to be 1.42m and 0.44m, respectively the steady state pump discharge is.

220 gpm

Water held tightly to the surface of soil particle by adsorption forces is:

hygroscopic water

The peak runoff in a 50 ha-watershed corresponding to a rainfall intensity of 25 mm/hr and a runoff coefficient of 0.8 is

280 m3/s

Streamflow in a river was measured at various stages using a current meter. The results are given below: The stage-discharge relation of the form q = ahb is to be developed. Based on the observed data, the value of the exponent b is

0.9

It is the sheet of water which overflows a weir:

Napped

Sprinkler type with operating pressure from 20-40 psi:

low pressure

The type of erosion that takes place in small channels which cannot be obliterated by tillage operations is called

gully

An appurtenance to the pipeline which permits the passage of air to or from the pipeline.

vent

It is the combined process of evaporation and transpiration from plants.

evapo-transpiration

Barrier constructed to hold water back and raise its level.

dam

The volume of water flowing each second, measured in m3/sec.

discharge

Term for solar radiation received at the earth’s surface

insolation

The channel connected to the main canal which distributes irrigation to specific areas

Secondary canal

The minimum distance from the center of the lone pumped well wherein no drawdown will be observed is the _________________.

radius of influence

A 27 mm/day water requirement is equivalent to

3.125 lps/ha

On the weather map, lines representing points of equal pressure is called.

Isobars

Planting different crops simultaneously in the same field at the same cropping season.

Mixed/multiple cropping

Compute the unidirectional flow in two parallel drains; 1200 m apart if the soil hydraulic conductivity is 10m/day and the water level at the drains are 7 and 9 meters.

0.0056 m2/hr

Compute the land soaking requirement for a soil ( depth of rootzone = 35cm) with residual moisture content of 15% by mass, bulk density of 1,280 kg/m3 and porosity of 45%. Standing water for planting is 25 mm.

90.3 mm

A 25-ft thick confined aquifer with hydraulic conductivity of 500ft/day was tapped by a 4” shallow tubewell. With a radius of influence of 2000 ft, determine the maximum discharge of the STW in liters per second. Assume an allowable drawdown of 10 ft.

27.43

For an 8m x 8m sprinkler spacing, what is the design sprinkler throw for a 40% overlap?

5.6 m

Vigna radiata is commonly known as:

mungbean

Determine the design freeboard for a canal with a 100% safety factor for discharge. The canal bottom width is 1.2 meters and the inverse side slope is 1.75. The design discharge is 10. 4427 m3/s; roughness coefficient is .015 and the water surface slope is 5x10-3.

0.58 m

An unconfined aquifer is situated above a horizontal impervious base and is composed of sand with a hydraulic conductivity of 12m/day. In this aquifer, two fully penetrating ditches form a strip of land with a constant width of 1250m. The water level in the left and right ditches rises to 8 and 12m above the impervious base, respectively. The recharge by rainfall is 7.5 mm/day. Evaporation losses amount to 2.5 mm/day. Compute the flow into the right drain.

3.509 m2 / day

2.741 m2 / day

16.11 m

The 60 cm deep rootzone of a soil has volumetric field capacity and wilting point of 0.345 and 0.236 respectively. Crop consumptive use is 7.2 mm/day. Compute for the irrigation interval assuming there is 1.7 mm daily rainfall and 80% allowable moisture depletion.

9 days

For the most efficient trapezoidal cross-section:

width of the bottom=twice the depth

A conveyance structure used to turn conduits of varying sizes and shapes

transition

Surface irrigation method where a much smaller area is enclosed by levees.

basin flooding

The critical depth in a rectangular channel with a bottom width of 4.0 m for a discharge of 5 m3/s is

0.54 m

That part of surface runoff that flows over the surface towards the stream channel

Overland flow

Erosion of stream banks by flowing water.

Stream bank erosion

A 30-inch diameter 1-meter long culvert has been designed to carry a maximum discharge of 1.7 m3/s when flowing half-full. Its roughness coefficient n is 0.014. If the inlet and the outlet are both unsubmerged, the difference in elevation between the inlet and the outlet should be

12.5 cm

What is the depth of water in a trapezoidal channel with a side slope of 2 and carrying a 2.5 m3/s water flow? The channel’s bottom width is 1.5 meters and the flowing water has a velocity of 0.8 m/s.

0.93m

A vertical section to the soil mass where significant changes in the soil texture and structure with depth are observed

Soil profile

The moisture content of the soil when tension is 1/3 atmosphere.

Field capacity

100

This refer to the additional height or depth of hydraulic structures

Free board

EXAM 6

Heyzel Valdez · 100問 · 1年前

EXAM 6