SWCE PT.1 Flashcards
- The factor that affects adoption of soil
and water conservation measures
a. land tenure
b. high initial investment cost
c. construction skills
d. both a and
e. all of the above
Answer: e. all of the above
- A wet area, periodically inundated with standing or
slow moving water, that has grassy or herbaceous
vegetation and often little peat accumulation; the
water may be salt, brackish or fresh
a. karst
b. Marsh
c. Peat
d. Valley
Answer: b. Marsh
- Regions that are characterized by formations
underlain by carbonate rock typified by the
presence of limestone caverns and sinkholes
a. Karst
b. Marsh
c. Peat
d. Wetland
Answer: a. Karst
- Which of the following is not a soil structure?
a. Loam
b. Crumb
c. Platy
d. Sub-angular blocky
e. Prismatic
Answer: a. Loam
- Soil productivity is the ability of the soil
a. To produce the desired amount of plant yield
b. Supply nutrients in sufficient and balanced
amounts
c. Store and resist leaching nutrients
d. All of the above
Answer: a. To produce the desired amount of plant yield
- When a sickly yellowish green color was found,
the plant was possibly suffering from what
major element deficiency?
a. Nitrogen
b. Boron
c. Phosphorus
d. Zinc
e. Potassium
Answer: a. Nitrogen
- Refers to the manifestation of physical forces of
cohesion and adhesion acting within the soil at
various moisture contents.
a. Soil consistency
b. Soil aggregate
c. Soil cohesion
d. Soil structure
e. Soil texture
Answer: a. Soil consistency
- It has the property of soil which enables clay
to change slope without cracking when it is
subjected to deforming stress.
a. Puddlability
b. Permeability
c. Friability
d. Consistency
e. Plasticity
Answer: e. Plasticity
- Refers to the relative proportion of various size
groups of individual soil grains:
a. Soil texture
b. Soil consistency
c. Soil colloid
d. Soil profile
e. Soil structure
Answer: a. Soil texture
- Water which has been absorbed from an
atmosphere of water vapor as a result of
attractive forces in the surface of the particles.
a. Capillary water
b. Hygroscopic water
c. Rainwater
d. Gravitational water
e. Mineral water
Answer: b. Hygroscopic water
Kinds of Soil Water
Hygroscopic water – water held tightly to the surface of soil particles by adsorption forces
Capillary water – water held by forces of surface tension and continuous film around soil particle and
capillary spaces
Gravitational water – water that moves freely in
response to gravity and drains out of the soil
- It is refer to the ease of crumbling of soils.
a. Plasticity
b. Soil colloid
c. Soil consistency
d. Friability
Answer: d. Friability
- A natural body composed of a variable mixture of
broken and weathered minerals and decaying
organic matter and when containing the proper
amount of air and water, supplies sustenance
and gives mechanical support of plants:
a. Fertilizer
b. Soil
c. Humus
d. Rock
e. Mineral
Answer: b. Soil
- The study of soil which puts more emphasis
on the origin, characteristics, classification
and description:
a. Pedology
b. Pathology
c. Agronomy
d. Soil science
Answer: a. Pedology
- 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:
a. Wilting point
b. Hygroscopic coefficient
c. Air dry
d. Field capacity
e. Oven dry weight
Answer: d. Field capacity
Soil Moisture constants:
1. Saturation Capacity – all pores of the soil are filled
with water - Maximum water-holding capacity
2. Field Capacity (FC) – is the moisture content after
drainage of gravitational water has become very slow and the moisture content has become relatively stable
3. Permanent Wilting Point/Percentage (PWP) – moisture content at which plants can no longer obtain enough moisture to meet transpiration requirement and remain wilted (and eventually dies) unless water is added
4. Moisture equivalent – amount of water retained by a sample of initially saturated soil material
5. Wilting Range – range in soil moisture content which plants undergo progressive degree of permanent or irreversible wilting
6. Available Water – soil moisture between field capacity and permanent wilting
point
- The capacity of water bodies to cleanse
themselves of pollutants over a period of time
and/or stretch
a. Stress capacity
b. Driving capacity
c. Assimilative capacity
d. Water holding capacity
Answer: c. Assimilative capacity
- Are natural drainage areas within the
boundary defined by the divide
a. Watershed
b. Catchment
c. Basin
d. All of the above
Answer: d. All of the above
The following are watershed descriptors,
except
a. Drainage density
b. Basin shape
c. Relief ratio
d. Stream order
e. Flood routing
Answer: e. Flood routing
- A watershed descriptor that describes the
dissection of a basin and determines its
response to a rainfall input
a. Drainage density
b. Circulatory ratio
c. Relief ratio
d. Stream order
e. Stream gradient
Answer: a. Drainage density
- The area of a drainage basin is approximately
10000 acre with an average length of 2500m. The
elevation of the remote place of the basin from the
outlet stream is 1000m. What is the estimated
time where the flow reaches the outlet stream.
a. 0.191
b. 0.155
c. 0.595
d. 0.115
Answer: a. 0.191
The ratio of the circumference of a circle, of
the same area as the basin, to the basin
perimeter
a. Circulatory ratio
b. Elongation ratio
c. Relief ratio
d. Circumferential ratio
Answer: a. Circulatory ratio
The capacity of rainfall (precipitation) to effect
the detachment and transport of soil particles.
a. Erodibility
b. Erosivity
c. Effectivity
d. Conductivity
Answer: b. Erosivity
Soil Erosion –is the detachment and transport of soil particles by natural (i.e. water and wind) or anthropogenic (man-induced or man-related) causes.
Soil Erodibility – the susceptibility of the soil to be
eroded
Rainfall Erosivity – the capacity of rainfall to cause
erosion
Eroding agents – rainfall/raindrop, runoff, wind
Which of the following is not a purpose of
terracing?
a. To reduce soil erosion
b. For water conservation
c. For flood control
d. For soil fertility rejuvenation
e. None of the above
Answer: d. For soil fertility rejuvenation
Soil erosion is the _______ of soil particles
by natural or anthropogenic causes.
a. Detachment
b. Detachment and transport
c. Detachment, transport and deposition
d. Detachment and entrainment
e. Detachment, transport and entrainment
Answer: b. Detachment and transport
The following are on-site effects of erosion,
except
a. Reduced crop productivity
b. Reduced infiltration
c. Increased of direct runoff
d. Damaged biodiversity
e. None of the above
Answer: e. None of the above
The following factors are represented in the
USLE except:
a. Rainfall erodibility
b. Cover management
c. Slope length
d. Conservation practice
e. Relief
Answer: e. Relief
The detachment and transport of soil by a
concentrated flow of water.
a. Sheet erosion
b. Rill erosion
c. Interill erosion
d. Streambank erosion
Answer: b. Rill erosion
Cropping systems where strips of some grass or
legume crop are laid out between strips of crops in
the regular rotations; they may be even or irregular
in width; they may be placed on critical slope areas
of the field
a. Buffer strip
b. Contour strip
c. Field strip
d. Random strip
Answer: a. Buffer strip
It is an organic or synthetic permeable
cloth-like material used for soil
conservation and erosion prevention
a. Geotextile
b. Geosynthetics
c. Geomesh
d. Both a and b
e. All of the above
Answer: e. All of the above
On a 10% hill slope, it is proposed to
construct bench terraces of vertical cuts. . If
the vertical interval is 2 meters, what is the
width of the terrace?
a. 10 m
b. 8 m
c. 20 m
d. 16 m
Answer: c. 20 m
Which is a correct description of a soil erosion
plot used to experimentally measure soil
erosion?
a. Vegetated
b. 9% slope
c. 20 m long
d. 7.26 ft high
Answer: b. 9% slope
Methods of Soil Erosion Measurement:
Soil erosion plots (standard conditions: bare fallow, 9% slope, 72.6 ft. length)
It is the process by which land is left idle or
uncropped for one or more seasons to
accumulate moisture, destroy weeds and allow
decomposition of crop residues.
a. Ratooning
b. Fallowing
c. Idling
d. Mulching
Answer: b. Fallowing
A type of terrace usually used for 25-30%
slope characterized by the construction of
series of platforms along the contours cut into
hill slope in a step like formation
a. Bench terrace
b. Broad-based terrace
c. Zingg terrave
d. Manning’s terrace
Answer: a. Bench terrace
How does a gully develop?
1. stabilization stage
2. channel erosion by downward scour of the topsoil
3. healing stage
4. upward movement of gully head and enlargement
of the gully width
a. ii, iv, i, iii
b. iv, ii, iii, i
c. ii, iii, iv, i
d. ii, iv, iii, i
Answer: d. ii, iv, iii, i
The USLE is a method of computing soil
erosion. What type of soil erosion does it
estimate?
a. Sheet erosion only
b. Sheet, rill and gully erosion
c. Sheet and rill erosion only
d. All types of erosion
Answer: a. Sheet erosion only
What is the Kinetic Energy per unit area of a
rainfall with depth of 0.18 in & intensity of
1.35 in/hr?
a. 12.5
b. 15.2
c. 17.2
d. 173
Answer: d. 173
If the total kinetic energy of a given rainfall
event is 7500 ft-ton/acre and the highest I30 is
10 in/hr, what is the Rainfal erosivity index of
the rainfall event?
a. 0.143
b. 0.562
c. 14.3
d. 750
e. 75000
Answer: a. 0.143
A sandy loam soil (Sand = 65%, silt=26%,
clay = 9%) has a pH of 5.6 and organic
matter content of 4.8%. Determine the soil
erodibility factor K.
a. 0.125
b. 0.235
c. 0.275
d. 1.25
Answer: b. 0.235
The soil erosion in a certain 10-ha farm
practicing conventional tillage (P factor = 1.0)
was computed to be 50 T/ha/yr. By what
percentage will be the difference in soil erosion
if zoning (P factor = 0.25) was employed?
a. 25% increase
b. 75% increase
c. 25% decrease
d. 75% decrease
Answer: d. 75% decrease
On a 20% hill slope, it is proposed to construct
bench terraces with 1:1 batter slope. If the
vertical interval is 2 meters, what is the width
of the terrace?
a. 10 m
b. 8 m
c. 20 m
d. 12 m
Answer: a. 10 m
These types of soil should not be used in dam
construction, except:
a. Organic material
b. Non-cracking clays
c. Fine silts
d. Calcitic clays
Answer: b. Non-cracking clays
The wetting or drying of a soil to assist compaction
a. Water treatment
b. Water logging
c. Moisture conditioning
d. Puddling
Answer: c. Moisture conditioning
Rainfall erosivity, R, obtained by ______ the
kinetic energy by the _____ rainfall intensity
during the a period of ____ for each rainstorm.
a. Multiplying, average, 15 minutes
b. Dividing, maximum, 30 minutes
c. Multiplying, maximum, 30 minutes
d. Dividing, minimum, 15 minutes
Answer: c. Multiplying, maximum, 30 minutes
The slope length in RUSLE is defined as
a. A distance from the origin of overland flow to
where the flow enters a concentrated flow
area
b. Distance from the origin of overland flow to
where deposition starts to occur
c. Distance to which transport capacity is lower
than sediment load
d. Distance to which transport capacity is higher
than sediment load
Answer: a. Distance from the origin of overland flow to
where the flow enters a concentrated flow area
Are rough bundle of brushwood or other material
used for strengthening an earthen structure
a. Wattles
b. Gabions
c. Fascines
d. stakes
Answer: c. Fascines
A patented mean for erosion protection in the
form of wire baskets or mattresses selectively
filled in situ with rock
a. Revetment
b. Abutment
c. Geotextile
d. Gabion
e. wattles
Answer: d. Gabion
Water held in the soil between field capacity
and permanent wilting point
a. Available water content
b. Soil water deficit
c. Excess water
d. Retained water
Answer: a. Available
water content
The government agency that issues ‘Water
Permits’ for extraction and use of natural
water resources
a. LGU
b. NWRB
c. DENR
d. DA
e. NIA
Answer: b. NWRB
This is the top of an embankment
a. Berm
b. Crest
c. Dike
d. Freeboard
Answer: b. Crest
Sediment near the stream bottom which
moves by crawling or sliding
a. Suspended load
b. Bed load
c. Saltation load
d. None of the abov
Answer: b. Bed load
Bed Load
– sediment near or few inches from the stream
bed and move by crawling or sliding
Suspended Load
– sediment or soil particle suspended in the water body
-sediment that is in motion in a river
Saltation – sediment transported by “saltation”
or “jumping”
When is the best/recommended time to
sample sediment load in the stream?
a. Intermittent flow
b. Base flow
c. Peak flow
d. Perennial flow
Answer: c. Peak flow
Method of sediment sampling where a
representative sample is taken from several
samples (likewise, taken from the different
locations) in the channel or reservoir
a. Composite sample
b. Point-integrated sample
c. Depth-integrated sample
d. Location-integrated sample
Answer: a. Composite sample
Method of sediment sampling where a
representative sample is taken by lowering and
raising the sampling container within the
height of the channel or reservoir
a. Composite sample
b. Point-integrated sample
c. Depth-integrated sample
d. Location-integrated sample
Answer: c. Depth-integrated sample
Temporal distribution of rainfall refers to
a. Distribution over space
b. Distribution over watershed
c. Distribution over time
d. Temporary distribution
Answer: c. Distribution over time
Which of the sediment sampling methods could
be done at the same time
1.Composite sampling
2.Point-integrated sampling
3.Depth-integrated sampling
a. 1 and 2
b. 1 and 3
c. 2 and 3
d. 1, 2, and 3
e. None
Answer: a & b
A reservoir has a capacity of 6x106 m3 and a drainage area of 200 km2. Streamflow averages 350mm of runoff per year and sediment production is estimated at 1100 metric tons per km2. How long will it take to reduce the reservoir capacity to 1 x 106 m3. Assuming an average inplace
density of 1500 kg/m3.
a. 41.5 years
b. 40 years
c. 47 years
d. 60 years
Answer: a. 41.5 years
It is the water retained around individual soil
particles by molecular action and can be
removed only by heating.
a. Permanent wilting point
b. Hygroscopic water
c. Hydrophobic water
d. Microscopic water
Answer: c. Hygroscopic water
It is the right of each land owner along the
stream which entitles him/her to have the water
flow in its natural channel undermined in
quantity and unpolluted in quality.
a. Appropriation right
b. Riparian right
c. Water right
d. Irrigation right
Answer: b. Riparian right
The process of determining the stage height,
storage volume and outflow rate from a reservoir
or a stream reach for a particular inflow
hydrograph is called
a. Synthetic hydrograph
b. Flood routing
c. Channel straightening
d. Water conservation
Answer: b. Flood routing
It is safety valve of a dam. Its main function is
to release surplus or flush flood water which
cannot be contained in the active storage of the
reservoir
a. Free board
b. Spill way
c. Sluiceway
d. Flume
Answer: c. Sluiceway
Its purpose is to prevent erosion at the toe of the dam
which might result to failure to structure. As water
discharges over an overflow dam most of its potential
energy are converted into kinetic energy thus
producing high velocities and causes erosion at toe of
the structure
a. Apron
b. Flume
c. Weir
d. Spillway
Answer: a. Apron
The moisture content of the soil when the
gravitational water has been removed
a. Available water
b. Field capacity
c. Permanent wilting point
d. Readily available moisture
Answer: b. Field capacity
The part of the reservoir (i.e. dam) designed to
store sediments
a. Active storage
b. Useful storage
c. Dead storage
d. Freeboard
e. Intake
Answer: c. Dead storage
One liter per second is equal to
a. 16.85 gpm
b. 15.5 gpm
c. 15.85 gpm
d. 17.35 gpm
Answer: c. 15.85 gpm
For a watershed of 360 hectares, the peak runoff
rate for a 0.5 cm/hr rain intensity (at the
time of concentration) was observed at 2.5
m3/s. What is the run-off coefficient?
a. 0.5
b. 5.0
c. 0.005
d. 0.05
Answer: a. 0.5
A reservoir, with water surface area averaging 6 km2
,
reads 100 m in its monitoring gauge. The reservoir is
being replenished by a 5000-ha watershed wherein
85% of the total rainfall that falls in the watershed
reaches the reservoir. What rainfall depth is needed to
raise the water level of the reservoir by 4 meters?
a. 655 mm
b. 556 mm
c. 565 mm
d. 665 mm
e. 656 mm
Answer: c. 565 mm
Four liters per second is equal to
a. 14.4 m3
/hr
b. 63.41 gpm
c. Both a and b
d. Neither a nor b
Answer: c. both a and b
A crop sown with another crop and
harvested separately is called
a. Cover crop
b. Relay crop
c. Inter-tilled Crop
d. Companion crop
Answer: d. companion crop
A channel having steep slope
a. Flume
b. Chute
c. Main canal
d. Checkgate
e. Lateral canal
Answer: b. Chute
The distance between adjacent terraces
a. Horizontal distance
b. Vertical distance
c. Horizontal interval
d. Vertical interval
Answer: d. Vertical interval
Is the elevation or vertical distance of the
free water surface above a datum
a. Stage
b. Depth of flow
c. Channel depth
d. Hydraulic depth
e. Both a and b
Answer: a. Stage
The following measures accelerates
channel flow, except,
a. Channel deepening
b. Channel straightening
c. Levees
d. Channel widening
e. Vegetative control
Answer: e. Vegetative control
Involves the arrangement of compost mix in
long, narrow piles that are periodically turned
to maintain aerobic conditions
a. Windrow
b. Conical
c. Granular
d. Silo-type
e. None of the above
Answer: a. Windrow
Which is a natural or vegetative soil conservation
technology
a. Terracing
b. Mulching
c. Wattling
d. Brush dam
e. Detention structures
Answer: b. Mulching
These are characteristics of contour maps, except:
a. All points on the same contour have the same
elevation
b. Regardless of slopes, the contour lines are spaced
uniformly.
c. A single contour cannot lie between two contour
lines or higher elevation.
d. Every contour closes upon itself either within or
outside the limits of the map.
e. A contour never splits.
Answer: b. Regardless of slopes, the contour lines are
spaced uniformly.
Determine the Kinetic energy per unit area,
MJ/ha, if a rainfall event occurring within 10
min has an intensity of 60 mm/hr.
a. 1.75
b. 2.74
c. 3.75
d. 4.75
e. 5.05
Answer: b. 2.74
Given a total Kinetic energy of 3000 KJ/ha and
rainfall intensity (highest for any 30 mins) of 25
mm/hr, determine the rainfall erossivity (N/hr).
a. 5.25
b. 6.50
c. 7.50
d. 7.75
e. 100.50
Answer: c. 7.50
A stormwater management facility that
temporarily impounds runoff and discharges it
through a hydraulic outlet structure to a
downstream conveyance system.
a. Detention basin
b. Bioretention basin
c. Catch basin
d. Bioremediation basin
Answer: a. Detention basin
Type of sediment load along the stream
characterized as sediments that are sometimes
stationary and sometimes carried by the water
along the stream.
a. Saltating load
b. Temporary load
c. Bed load
d. Suspended load
Answer: a. Saltating load
A small water impounding reservoir with a capacity
of 1,500 cu. m. was constructed on a catchment area
of 100 hectares. If the annual sediment prediction is
4.26 m3/ha, what is the probable life of the reservoir
before its capacity is reduced to 500 cu. m? Assume
trap efficiency of dam of 31%
a. 5.4 years
b. 13.6 years
c. 26.3 years
d. 7.6 years
Answer: d. 7.6 years
Yearly Fillage (m3/yr) = Trap Efficiency × total amount of sediment production (m3/yr)
Time of Fillage (yrs) = capacity (m3)/yearly fillage (m3/yr)
Side of embankment wetted by the
impounded water
a. Wetted perimeter
b. Upstream face
c. Downstream face
d. Berm
e. crest
Answer: b. Upstream face
For STW with design discharge of more or less
7.6 Lps and service area of greater than 2 ha,
recommended well/pipe diameter is
a. 2
b. 3
c. 2 or 3
d. 3 or 4
e. 4
Answer: d. 3 or 4
The following are Gabion Dam construction
considerations, except,
a. Stones should be non-disintegrating and resistant to
abrasion and weathering
b. Correct lacing should be done if there are more than one
layer of boxes.
c. The space behind the dam and wing walls shall be filled with
soil.
d. Shall not be constructed on points where there is mass
movement of soil block
e. The height of a wing wall is equal to the depth of the spillway
Answer: d. Shall not be constructed on points where
there is mass movement of soil block
Rise in maximum flood level from the original
unobstructed flood level which results due to
obstruction such as check or diversion dam
a. Afflux elevator
b. Reflux elevator
c. Rated elevator
d. Freeboard
e. stage
Answer: a. Afflux elevator
The type of diversion dam which has a high
discharge efficiency and adaptable to most
sites under normal condition
a. Corewall
b. Gated
c. Glacis
d. Ogee
e. Vertical drop
Answer: d. Ogee
A small barrier across the direction of water
flow on shallow river and streams to convey
runoff during peak flow.
a. Rockfill dam
b. Diversion dam
c. Check dam
d. Detention dam
e. Any of the above
Answer: c. check dam
Distance from irrigation area to the community
of concern that is sensitive to contamination
(e.g. when re-using wastewater)
a. Safe zone
b. Buffer zone
c. Setback distance
d. Allowable distance
e. Precautionary distance
Answer: c. seatback distance
A plot of flow/runoff versus its probability of
occurrence
a. Hydrograph
b. Histogram
c. Rating Curve
d. Flow duration curve
Answer: d. Flow duration curve
These are natural and vegetative soil
conservation technologies, except
a. Dibble Planting
b. Alley planting
c. Strip planting
d. Wattling
e. mulching
Answer: d. Wattling
