Soil and Water Conservation Engineering

Question 1

Slope of the upstream face of the embankment.

Answer 1

Inside slope

Question 2

Inside bottom or sill of the conduit.

Answer 2

Invert

Question 3

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.

Answer 3

Inverted siphon

Question 4

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

Answer 4

Land preparation

Question 5

_________ 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.

Answer 5

Land soaking

Question 6

Spacing between irrigation laterals.

Answer 6

Lateral spacing

Question 7

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

Answer 7

Leaching

Question 8

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

Answer 8

Lined canal

Question 9

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

Answer 9

Loading limit

Question 10

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

Answer 10

Manifold

Question 11

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

Answer 11

Natural spillway

Question 12

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

Answer 12

Normal depth

Question 13

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

Answer 13

Normal storage

Question 14

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

Answer 14

Design depth

Question 15

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

Answer 15

Inundation

Question 16

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

Answer 16

Avoid sedimentation

Question 17

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.

Answer 17

Partially full

Question 18

Part of the system that impounds the runoff.

Answer 18

Reservoir

Question 19

Slope at the downstream face of the embankment.

Answer 19

Outside slope

Question 20

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

Answer 20

Pan coefficient

Question 21

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

Answer 21

Pan evaporation

Question 22

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.

Answer 22

Percolation

Question 23

Vertical flow of water to carry salts contained in water.

Answer 23

Leaching

Question 24

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

Answer 24

Permeability test

Question 25

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

Answer 25

Soil erosion

Question 26

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

Answer 26

Bench terrace

Question 27

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

Answer 27

Green manuring

Question 28

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

Answer 28

Contouring

Question 29

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

Answer 29

Pin method

Question 30

Advanced form of erosion.

Answer 30

Gully erosion

Question 31

Dam which resists water flow of water by its weight.

Answer 31

Gravity dam

Question 32

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

Answer 32

Gabion dam

Question 33

Material used to cover the soil to minimize evapotranspiration.

Answer 33

Mulch

Question 34

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

Answer 34

Karst topography

Question 35

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

Answer 35

Paspalum conjugatum

Question 36

Philippine geographical constant for determining terrace vertical interval.

Answer 36

A. 0.5

Question 37

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

Answer 37

1

Question 38

Estimate the peak runoff rate from a 20-hectare drainage basin if rainfall depth for 6 hours reached 60 mm. Use typical runoff coefficient of 0.35.

Answer 38

I = 60 mm/6 hrs = 10 mm/hr
q = 0.0028 CIA = 0.0028 (0.35)(10 mm/hr)(20 has) = 0.2 cms

Question 39

Estimate the runoff volume from a 20-hectare drainage basin if rainfall depth for 6 hours reached 60 mm and duration of runoff is about 3 hours. Use typical runoff coefficient of 0.35.

Answer 39

I = 60 mm/6 hrs = 10 mm/hr q = 0.0028
CIA = 0.0028 (0.35)(10 mm/hr)(20 has) = 0.2 cms
Q = 0.5qT = 0.5 (0.2 cms) (3 hrs) (3600 s/hr) = 1,080 cms