AE BOARD EXAMINATION REVIEWER – 2018

SUBJECT 2
Soil and Water Resources Devt. and Conservation, Irrigation, Drainage and Allied Subjects

Arthur It. Tambong, FPSAE

INSTRUCTIONS:

Select the best answer.

I. Hydrology (10%)

Easy Questions

1. Method of areal rainfall estimation done by getting the weighted average.

A. Averaging method B. Arithmetic method C. Polygon Method D. Isohyetal method

Answer: B

2. An instrument to measure rainfall depth.

A. Rain gage B. Rainfall dip stick C. Bucket D. Rainfall meter

Answer: A

3. Is that part of rainfall which runs off the soil as surface or subsurface flow.

A. Flood B. Infiltration C. Percolation D. Runoff

Answer: D

4. The ratio of runoff over rainfall.

A. Runoff ratio B. Runoff/rainfall ratio C. Runoff coefficient D. Rainfall ratio

Answer: C

5. A drop of water greater than 0.5 mm falling from the atmosphere.

A. Atmospheric rainfall B. Torrential rainfall C. Precipitation D. Effective rainfall

Answer: D

6. Kind of thermometer with constriction to prevent easy return of liquid to the bulb.

A. Maximum thermometer B. Minimum thermometer C. Air thermometer D. Autothermometer

7. The inverse of the probability of exceedance of a certain hydrologic event.

A. Return period B. Probability of inceedance C. Hydro probability D. Event probabilty

Answer: A

8. Natural airmass lifting process facilitated by sunlight.

A. Natural B. Orographic C. Mountain lifting D. Convective

Answer: D

9. Natural airmass lifting process facilitated by mountain formation.

A. Natural B. Orographic C. Mountain lifting D. Convective

Answer: B

10. Dominant form of precipitation in the Philippines.

A. Rainfall B. Flood C. Runoff D. Evaporation

Answer: A

Moderate Questions

11. Probability of occurrence in any year of hydrologic event recurring once in 2 years.

A. 20% B. 2% C. 100% D. 50%

Answer: D
Prob. = (1/Return Period) x 100 = (½) x 100% = 50%

II. Irrigation and Drainage Engineering (45%)

Easy Questions

12. The maximum permissible water velocity for clay loam canal surface based on PAES
603:2016.

A. 0.80 m/s B. 0.9 m/s C. 1 m/s D. 1.2 m/s

Answer A

13. The minimum permissible velocity for water with sediments in lined canals based on PAES
603:2016.

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 A. 0.80 m/s B. 0.9 m/s C. 1 m/s D. 1.2 m/s

Answer B

14. Application of water in the soil to supply moisture needed for plant growth.

A. Irrigation B. Sprinkling C. Flooding D. Diverting

15. Loss of water from a channel during transport due to seepage and percolation.

A. Channel loss B. Conveyance loss C. Percolation loss D. Seepage loss

Answer: B

16. Depth of water flow where the energy content is at minimum hence, no other backwater forces
are involved.

A. Minimum depth B. Energy depth C. Critical depth D. Normal depth

Answer: C

17. Ratio of the actual crop evapotranspiration to its potential evapotranspiration.

A. Crop ratio B. Crop coefficient C. ET ratio D. Evaporation ratio

Answer: B

18. Moisture content of the soil when gravitational water has been removed.

A. Field capacity B. Gravitational moisture C. Soil capacity D. Specific capacity

Answer: A

19. Number of days between irrigation applications.

A. Irrigation interval B. Application interval C. Dry interval D. Node interval

Answer: A

20. Removal of excess water.

A. Squezzing B. Run off C. Discharging D. Drainage

Answer: D

21. Elevated section of open channel used for crossing natural depressions.

A. Parshall flume B. Flume C. Siphon D. Elevated channel

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 Answer: B

22. Surveying instrument used for determining land areas in a topographic maps.

A. Areometer B. Erometer C. Planimeter D. Lysimeter

Answer: C

23. Elevation of water surface in a stream with reference to a certain datum.

A. Stage B. Surface elevation C. Contour D. Water elevation

Answer: A

24. Facility for determining water consumptive use of crops in an open field.

A. Planimeter B. Lysimeter C. Consumeter D. Crop meter

Answer: B

25. Time required to cover an area with one application of water.

A. Irrigation interval B. Irrigation period C. Supply duration D. Application time

Answer: B

Difficult Questions

26. At optimal emitter spacing, drip emitter spacing is ___ of the wetted diameter estimated from
field tests.

A. 100% B. 90% C. 80% D. 85%

Answer: C

27. Reference crop evapotranspiration is the rate of evapotranspiration from a reference surface
which is a hypothetical reference crop with an assumed crop height of 0.2 m and an albedo of ____.

A. 0.23 B. 0.25 C. 0.30 D. 0.32

Answer: A

28. Manufacturer’s coefficient of variation is the measure of the variability of discharge of a random
sample of a given make, model and size of emitter, as provided by the manufacturer and before any
field operations or aging has taken place determined through a discharge test of a sample of 50
emitters under a set pressure at ___ ºC.

A. 200 B. 100 C. 50 D. 30

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 Answer: A

III. Soil and Water Conservation Engineering (30%)

Easy Questions

29. Slope of the upstream face of the embankment.

A. Downstream slope B. Outside slope C. Inside slope D. Upsteam slope

Answer: C

30. Inside bottom or sill of the conduit.

A. Invert B. Inside base C. Inside sill D. Bottom sill

Answer: A

31. Closed conduit designed to convey canal water in full and under pressure running condition, to
convey canal water by gravity under roadways, railways, drainage channels and local depressions.

A. Close siphon B. Pressurized conduit C. Siphon D. Inverted siphon

Answer: D

32. __________ water requirement is the amount of water required in lowland rice production which
includes water losses through evaporation, seepage, percolation and land soaking.

A. Land preparation B. Irrigation C. Crop D. Field

Answer: A

33. _________ water requirement is the amount of water required in lowland rice production which
is a function of the initial soil moisture and the physical properties of the soil.

A. Land preparation B. Irrigation C. Crop D. Land soaking

Answer: D

34. Spacing between irrigation laterals.

A. Ditch spacing B. Lateral spacing C. Horizontal spacing D. Irrigation spacing

Answer: B

35. Deep percolation of water beyond the root zone of plants, resulting in loss of salts or nutrients.

A. Vertical percolation B. Root zone percolation C. Leaching D. Salt leaching

Answer: C

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36. Canal with impermeable material (usually concrete) for channel stabilization and/or reduced
seepage.

A. Line canal B. Lined canal C. Unlined canal D. Impermeable canal

Answer: B

37. Allowable pollutant-loading limit per unit of time, which the wastewater generator is permitted to
discharge into any receiving body of water or land.

A. Pollutant limit B. Loading limit C. Allowable limit D. Wastewater limit

Answer: B

38. Portion of the pipe network between the mainline and the laterals.

A. Diversion pipe B. Manifold C. Main-lateral pipe D. Reducer

Answer: B

39. Spillway which is not excavated such as natural draw, saddle or drainage way.

A. Surface spillway B. Flood spillway C. Natural spillway D. Earth spillway

Answer: C

40. Constant flow depth along a longitudinal section of a channel under a uniform flow condition.

A. Critical depth B. Constant depth C. Laminar depth D. Normal depth

Answer: D

41. Maximum elevation of the water surface which can be attained by the spillway-type dam or
reservoir without flow in the spillway.

A. Normal storage B. Maximum Storage C. Critical elevation D. Design depth

Answer: A

42. Maximum elevation of the water surface which can be attained in an open channel without
reaching the freeboard.

A. Normal storage B. Maximum Storage C. Critical elevation D. Design depth

Answer: D

43. In what condition is the open channel freeboard used for water conveyance?

A. Maximum flow B. Emergency flow C. Inundation D. Rainy days

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 Answer: C

44. The primary purpose in limiting water flow not to go below minimum velocity.

A. Avoid percolation B. Avoid sedimentation C. Avoid critical depth D. Optimize flow

Answer: B

45. Open channel flow is water flow that is conveyed in such a manner that top surface is exposed to
the atmosphere such as flow in canals, ditches, drainage channels, culverts, and pipes under _____
flow conditions.

A. Full B. Partially full C. Normal D. Critical

Answer: B

46. Part of the system that impounds the runoff.

A. Storage B. Reservoir C. Impounding D. Runoff collector

Answer: B

47. Slope at the downstream face of the embankment.

A. Outside slope B. Inside slope C. Side slope D. Soil gradient

Answer: A

48. Ratio between reference evapotranspiration and water loss by evaporation from an open water
surface of a pan.

A. Pan coefficient B. Evaporation ratio C. Reference pan ratio D. ET ratio

Answer: A

49. Rate of water loss by evaporation from an open water surface of a pan.

A. Surface evaporation B. Sunken evaporation C. Pan evaporation D. Evaporation loss

Answer: C

50. Vertical flow of water below the root zone which is affected by soil structure, texture, bulk
density, mineralogy, organic matter content, salt type and concentration.

A. Leaching B. Percolation C. Infiltration D. Seepage

Answer: B

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51. Vertical flow of water to carry salts contained in water.

A. Leaching B. Percolation C. Infiltration D. Seepage

Answer: A

52. Method to determine the rate of flow under laminar flow conditions through a unit cross sectional
are of soil under unit hydraulic gradient.

A. Permeability test B. Laminar test C. Flow test D. Hydraulic test

Answer: A

53. Is the process by which the soil is removed from its natural place.

A. Soil removal B. Runoff C. Soil erosion D. Leaching

Answer: C

54. A kind of terrace which consists of a series of flattened areas.

A. Broad-base terrace B. Bench terrace C. Conservation terrace D. Rice terrace

Answer: B

55. The practice where legumes are plowed or incorporated into the soil.

A. Legume incorporation B. Legume manuring C. Green manuring D. Manuring

Answer: C

56. Farming practice where plowing and harrowing are done along the contour.

A. Contouring B. Strip cropping C. Crop row aligning D. Contour plowing

Answer: A

57. The simplest method of determining soil erosion over a period of time.

A. Catchment method B. Erometer method C. Plumb bob method D. Pin method

Answer: D

58. Advanced form of erosion.

A. Rill erosion B. Gully erosion C. Sheet erosion D. Advanced erosion

Answer: B

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59. Dam which resists water flow of water by its weight.

A. Resisting dam B. Buttress dam C. Gravity dam D. Arc dam

Answer: C

60. Dam consisting of stones enclosed in cyclone wires which allows water passage.

A. Gabion dam B. Stone dam C. Cyclone dam D. Interlink dam

Answer: A

61. Material used to cover the soil to minimize evapotranspiration.

A. Plastic B. Mulch C. Leaves D. Soil cover

Answer: B

62. Geological formation shaped by the dissolution of a layer or layers of soluble bedrock, usually
carbonate rocks such as limestone or dolomite.

A. Geological layer B. Dissolved layer D. Soluble layer D. Karst topography

Answer: D

63. Scientific name of carabao grass commonly used in vegetated open channels.

A. Glerisedia sepium B. Paspalum conjugatum C. Cyperus rotundos D. Leucaena leucocepala

Answer: B

Moderate Questions

64. Philippine geographical constant for determining terrace vertical interval.

A. 0.5 B. 0.8 C. 1 D. 1.5

Answer: A

65. Constant for soil erodibility and cover conditions for erodible soil and poor cover.

A. 0.5 B. 0.8 C. 1 D. 1.5

Answer: C

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Difficult Questions

66. A trapezoidal concrete gravity dam has vertical upstream wall. Water depth in the upstream
side is 50 meters above the dam base. Freeboard of 15% based on design depth. What is the
force of water exerted against dam per meter of dam width at deepest section?

A. 1,100 tonnes B. 1,150 tonnes C. 1,200 tonnes D. 1,250 tonnes

Answer: D
Solution:
P = 0.5 x Water density x H2 = 0.5 x1 tonne/m3 x (50 m)2 = 1,250 tonnes

67. A trapezoidal concrete gravity dam has vertical upstream wall. Water depth in the upstream
side is 50 meters above the dam base. Base of dam is 78 meters along water flow. What is the
uplift force of seepage water below the dam per meter of dam width at deepest section?

A. 1,900 tonnes B. 1,950 tonnes C. 2,000 tonnes D. 2,050 tonnes

Answer: B
Solution:
U = 0.5 x Water density x H x B = 0.5 x 1 tonne/m3 x 50m x 78m = 1,950 tonnes

68. A trapezoidal concrete gravity dam has inclined upstream wall. Resisting moment relative to
the dam toe is 263,953.2 tonne-meters while overturning moment is 96,233.3 tonne-meters per
meter of dam width at deepest section. What is the safety factor against overturning? Is it safe?

A. 0.36, unsafe B. 2.74, safe C. 3. 96, safe D. 5.48, excessively safe

Answer: B
Solution:
FSo = RM/OM = 263953.2/96233.3 = 2.74

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