Group 2

100問 • 10ヶ月前

問題一覧

A farm ditch has depth of flowing water of 60 cm, bottom width = 50 cm,side slope = 1horizontal:1vertical, channel slope = 0.02%. The velocity of flow in m/sec is:

0.314

A farm ditch has depth of flowing water of 60 cm, bottom width = 50 cm,side slope = 1horizontal:1vertical, channel slope = 0.02%. The discharge in m3/sec is:

0.207

Determine the size of a pump to irrigate a 5-ha riceland. The water source is a stream with a pumping head of 2 m. Evaporation = 8mm/day; Percolation = 2mm/day; Irrigation interval = 5 days Irrigation period = 10 hrs; Friction loss = 0; Pump efficiency = 80% Irrigation efficiency = 80%.

2.85 hp

Governed by chance; time dependent

Stochastic process

A farmer proposes to use sprinkler on a rectangular field 160m x 120m with lateral line parallel to the shorter side. The land is adjacent to the river from which he pumps water. He needs a maximum application depth of 60 mm every 10 days. The maximum intake rate of the soil is 8.5 mm/hr and the application efficiency is 80%. Sprinkler spacing is 9m x 9m. What is the desired discharge per sprinkler in lps?

0.19125 lps

Interval between corresponding points on successive terraces

Horizontal interval

It is a variation of the furrow method and it uses small rills or corrugations for irrigating closely spaced crops, such as small grains and pastures.

Corrugation irrigation

A farmer proposes to use a sprinkler on a rectangular field 160m x 120m with lateral line parallel to the shorter side. The land is adjacent to the river from which he pumps water. He needs a maximum application depth of 60 mm every 10 days. The maximum intake rate of the soil is 8.5 mm/hr and the application efficiency is 80%. Sprinkler spacing is 9m x 9m. How many sprinklers are in a lateral?

8.82 hrs

45.53

What should be the diameter of a pipe such that the two of them will be just sufficient to hold the water in an open canal 2 m wide and 1m deep? Assume half square section canal and use a common slope of 0.0007 and Chezy’s coefficient = 58.

1 m

Measures the velocity of a floating object preferably in a straight section of a stream

Float method

The following depths of water penetration in meters were observed at 10m interval along a furrow irrigation system:0.65, 0.66, 0.68,0.72, 0.73, 0.77,0.78, 0.80, 0.82, and 0.86. The uniformity coefficient is.

92%

Given the soil sampler with a diameter of 5.2 cm and length of 4.7 cm. What is the bulk volume of soil it could gather?

100 cc

A crop grown between orchard trees or on field between cropping season to protect the land from leaching and erosion:

cover crop

A crop which is planted in shortly before the first crop is to be harvested:

relay crop

The science or study of disease, its causes, and its controls:

Pathology

An engineer is to design the mainline of a sprinkler system which will use a steel (Scobey’s coefficient K = 0.40) to carry a flow of 6.5 lps. The length of pipe is 150m and the inside diameter is 100 mm. Compute the head loss of the system assuming a uniform flow.

1.36 m

A practical adaptation of reforestation whereby the species planted have economic value, such as mango, pili and so on.

Agroforestry

What is the evapotranspiration of corn during its growing period if the crop coefficient is 2.5 and the reference crop evapotranspiration is 6 mm/day?

15 mm/day

The composite parts of the irrigation system that divert water from natural bodies of water such as rivers, streams, and lakes

Headworks

The scientific name of strawberry:

Fragaria vesca

The crop water requirement of an area grown to a certain crop refers to the amount of water used for the non-consumptive demands such as land soaking and land preparation, and for the consumptive demands such as evapotranspiration requirements of the crop during its entire growth period.

Crop Water Requirement (CWR)

The soil has a field capacity of 30.8% volume basis and a permanent wilting point of 12% dry mass basis. The apparent specific gravity is 1.4. If the rootzone depth is 1.0m and the management allowable deficit is 50% the net application depth is.

70mm

The capacity of a certain canal will be measured using a Cipolleti weir having a length of 0.5m. If the height of the flowing water above the crest is 13 cm, what is the well capacity in lps?

43.59

With this discharge, what will be the head above the crest if a V-notch is installed somewhere along the same canal?

25 cm

Delivery of 360 cfs to an 80-acre field is continued for 4 hrs. Tail water flow is estimated at 10 cfs. Soil probing after the irrigation indicates that 1 ft. of water was stored in the rootzone. Compute the application efficiency.

67%

(Crop rotation) planting different crops, one after the other each season

Relay cropping

The duration of irrigation application for a 10ha cornfield for a given discharge of 100lps to obtain an average depth of application of 200mm assuming an application efficiency of 70% should be.

8 hrs

How much water is needed in each irrigation if the moisture holding capacity of the soil is 1.5 in/ft and irrigation were started when 40% is depleted. The crop us es 0.25 in/day of moisture and has a root depth of 3 ft. If there is no rain, how often will irrigation be required?

1.8 in. every 7.2 days

The name for seasonal winds (derived from Arabic mausim, a season)

Monsoon winds

The Philippine Agricultural Engineering law of 1998.

RA 8559

The Agriculture and Fisheries modernization act of 1998?

RA 8435

A notch of regular form through which the irrigation stream is made to flow and built as either portable or stationary structure.

Weir

Is soil detachment and transport resulting from the impact of water drops directly on soil particles or on thin water surfaces.

Splash / raindrop erosion

Compute the water holding capacity of soil in inches if the F.C. is 30% and the wilting point is 15% of the dry soil density. This density is 80 lbs/ft3 and the soil depth to be irrigated is 2 feet.

4.6

The mass per unit volume of the soil particle is:

soil density

Can stabilize the slopes of the gully and hence reduce runoff velocities

Grassed waterways

The trapezoidal canal is to have a base width of 6 m and side slopes of 1:1. The velocity of flow is 0.6 m/sec. What slope must be given the bed in order to deliver 5 m3/sec. Use Kutther’s C, n=0.025.

0.000263

Caused by the rising of warmer, lighter air in colder, denser surroundings.

Convective precipitation

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

Slip erosions

Given a probability of occurrence or exceedance of 5%. How many years will it take before a discharge of 1000 m3/sec will be equaled or exceeded?

Composite facilities that permit entry of water to paddy areas and consist of farm ditches and turnouts

On-Farm Irrigation Facilities

Given the following: bed slope = 0.0003 manning constant, n= 0.03 b/d ratio = 3.5 wetted perimeter = 14; z =0.5. The velocity of flow along a trapezoidal canal is?

0.82 m/s

It is accomplished by running water through small channels or furrows while it moves down or across the slope of the field.

Furrow irrigation

The recommended flow velocity on earth canals is.

0.30-1.0 m/s

Which is highly dependent on soil texture, refers to the downward movement of water through a depth of soil.

Percolation

A soil sample has wet mass of 120g and an undisturbed volume of 78cc. If the dry mass basis moisture content is 20%, the bulk density is.

1.28 g/cc

If the rectangular canal has base of 0.65 m, what would be the depth of flow when the hydraulic radius is equal to the area of flow.

0.17 m

The ____ is the amount of water to be applied to the field as irrigation.

Irrigation Water Requirement (IWR)

A concrete lined canal is to convey water over a distance of 250 m, from the well to farm, drop in elevation is 0.50 m over canal length and roughness coefficient, n=0.018. Estimate the bottom width of a rectangular canal with a depth of flowing water of 0.25 m, if the hydraulic radius is equal to the depth of flow?

0.5 m

A concrete lined canal is to convey water over a distance of 250 m, from the well to farm, drop in elevation is 0.50 m over canal length and roughness coefficient, n=0.018. ;depth of flowing water of 0.25 m What is the velocity of water in the canal?

0.62 m/s

Graphs that show interrelations between speed, head discharge, and horsepower of a pump.

Characteristic curve

The most hydraulically efficient trapezoidal channel section to carry a discharge of 5m3/s on a bed material with roughness n of 0.02 and a bottom slope of 1 in 800 should have a bottom width of.

1.65 m

A discharge of 20 L/sec is equivalent to.

72 cu.m/hr

That portion of the available moisture that is most easily extracted by plants; this is approximately 75% of the available moisture.

Readily available moisture (RAM)

Given an irrigation depth of 30cm and 10 hrs of irrigation time, determine the discharge needed to irrigate a hectare of land

300 cu.m/hr

Associated with the movement of air masses from high-pressure to low-pressure regions

Cyclonic precipitation

One liter per second is equal to.

15.85 gpm

Lands which display marked characteristics justifying the operation of an irrigation system

Irrigable Lands

A farm channel carries a flow of 20 L/s for a field using furrow irrigation. If each furrow required a flow of 1 L/s, how many furrows can be irrigated at a time?

A method of asexual propagation involving the transfer of aerial parts of one plant (scion) to the root or trunk material (stock) of another plant:

Grafting

The sequences of events occurring in a viable seed, starting with the inhibition of water, that leads to the growth and development of embryo:

Germination

A crop produced for direct sale for cash, as contracted with crops produced as livestock feed:

cash crop

An unlined trapezoidal irrigation canal is to carry a maximum discharge of 2,800lps. The side slope is to be set at 1:1. The head loss over a 1km distance is 1m. The Manning’s roughness coefficient is 0.025. If the maximum permissible velocity is 0.92m/s, the design depth should be.

0.95 m

The ratio of the normal consumptive use of water to the net amount of water depleted from the root zone soil.

Consumptive use efficiency

An agricultural engineer uses the quarter time rules in irrigating the field. If the contact time required to fill the soil reservoir is 1 day, how long will the water reach the far end of the field

360 min

The ratio between water stored in the soil root zone during irrigation and the water delivered to the farm expressed in percent.

Water application efficiency

An average depth of 100mm of water is needed to irrigate 5 ha of land in 20 hrs, what stream size is needed?

69.5 L/s

The velocity of flow into the soil caused by a unit hydraulic gradient in which the driving force is one kilogram per kilogram of water.

Permeability

75mm of water is needed to irrigate the field. In order to irrigate adequately over the whole area, an average depth of 100mm must be applied, how much water is lost

25 mm

The time rate at which water will percolate into the soil and can be expressed in terms of the following empirical equations

Infiltration rate

Suppose a farm channel 4km long with a cross-sectional area of 0.75 sq.m is to be filled with water before irrigation can begin. How long will this take when the discharge is 30Lps?

27 hours

Construction of earth embankment or ridge and channel across the slope at an acceptable grade to control the flow of runoff as well as soil particles.

Terracing

An 8 mm rainfall was measured by a USWB standard rain gauge, 8 inches in diameter. Determines the depth in the inner cylinder whose area is 1/10 of the catch area

80 mm

A 30inch diameter 1-meter-long culvert has been designed to carry a maximum discharge of 1.7m3/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.

30 cm

Erosion caused by wave action on the seashore.

Coastal Erosion

Determine the 10-year period peak runoff for a 80ha watershed having a runoff coefficient of 0.4, maximum length of water is 610m and the fall along this path is 6m. The rainfall intensity for that return period is 101.25mm/hr having duration equal to the time of concentration

9.0

Combination and splash and sheet erosion

Interrill erosions

The approximate threshold for the soil loss in the Philippines is around 12metric ton per hectare per year. Assuming a soil bulk density of 1.2 metric ton / cu. m, what is the soil erosion in mm/ yr.

1.0 mm / yr

Time for surface and interflow to recede; duration of flooding

Recession time

The discharge in a triangular channel with a vertex angle of 90 degrees is 390lps. The critical depth is.

0.5 m

What is the erosion rate in 10 ha farm with an average slope of 3%. Given: slope length factor = 1.0 soil erodibility = 0.25 conservation practice factor = 1.0 rainfall factor = 178

26.7 mm / yr

Same as groundwater runoff

Base flow

A flood flow of 560 cu.m per second was determined to have a 20% probability of occurrence. What is its return period?

5 years

For a watershed of 360 ha, the peak runoff rate for 0.5 cm/hr rain intensity (at the time of concentration) was observed as 2.5 cu.m/s. What is the runoff coefficient?

0.5

If the depth changes abruptly over a comparatively short distance such as in a hydraulic jump.

Rapidly varied flow

Is the detachment and transport of soil particles from the land by water or wind action.

Soil erosion

The theoretical flow velocity in an orifice is 4 m/s, what is the height of water flowing the center of the orifice?

81.6 cm

Which wets the entire land surface

By flooding

Determine the crest length of a structure for a chute spillway for a design flow of 1.4 cms and a maximum water level at the inlet is 0.5 m, the coefficient of discharge is 1.66.

2.38 m

Replanting of forest trees species in the watershed area

Agroforestry

A rectangular water tank, 2 m high is filled with water. Due to rust, a circular hole was made to the lowest portion of one side of the tank. Considering that the tank is maintained full, what is the velocity of water right after its take-off from the hole?

6.26 m/s

The channel where diverted water from a source flow to the intended area to be irrigated.

National irrigation system

The normal depth in a 2m wide concrete lined trapezoidal irrigation canal with a side slope z of 2 and a bottom slope of 0.2% for a discharge is 1.65 m3/s is.

1.6 m

The method of fertilizer application in which the fertilizer is dissolved in water as prescribed and then sprayed on the upper portion of the plant particularly the leaves:

broadcast method

The percentage of moisture on dry weight basis that is held against the pull of gravity, after drainage has ceased in a soil that has been saturated:

wilting point

Plants living more than one year but, in some cases, producing seed in the first year and every season thereafter:

quarter-annual

100

What is the water depth in a 24-inch diameter culvert which flows at 500 gpm and 2 ft/s velocity?

7.2 in

EXAM 6

Heyzel Valdez · 100問 · 1年前

EXAM 6