National Standards for Seepage and Percolation
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Which agency initiated the formulation of the national standard for the determination of seepage and percolation in open channels?

  • Bureau of Philippine Standards (BPS)
  • Bureau of Agriculture and Fisheries Standards (BAFS)
  • Philippine Council for Agriculture, Aquaculture and Forestry and Natural Resources Research and Development (PCAARRD)
  • Agricultural Machinery Testing and Evaluation Center (AMTEC) (correct)

What is the primary mandate of the Bureau of Agriculture and Fisheries Standards (BAFS) according to the Agricultural and Fisheries Mechanization Law of 2013?

  • To promote agricultural mechanization through funding initiatives.
  • To oversee the implementation of agricultural policies and regulations.
  • To develop standard specifications and test procedures for agricultural and fisheries machinery and equipment. (correct)
  • To conduct agricultural research and development projects.

Which document provides the rules for the structure and drafting of international standards under which this national standard was prepared?

  • Agricultural and Fisheries Mechanization Law of 2013
  • Republic Act 10601
  • Philippine National Standard repository
  • BPS Directives Part 3:2003 (correct)

In the context of this standard, the term 'shall' signifies what type of requirement?

<p>A mandatory requirement for compliance. (C)</p> Signup and view all the answers

What is the meaning of the term “should” as used in this national standard?

<p>It refers to a recommended option among several possibilities. (B)</p> Signup and view all the answers

Which of these is the title of the project that funded the development of this national standard?

<p>Enhancement of Nutrient and Water Use Efficiency Through Standardization of Engineering Support Systems for Precision Farming (C)</p> Signup and view all the answers

Which Bureau is responsible for endorsing this standard to the DA Secretary?

<p>Bureau of Agricultural and Fisheries Engineering (BAFE) (B)</p> Signup and view all the answers

What is the main focus of the standard PNS/BAFS/PAES 219:2017?

<p>Determining seepage and percolation in open channels using the ponding method. (C)</p> Signup and view all the answers

Which step involves determining and recording the dimensions of the selected channel section?

<p>Measuring the length and width of selected channel section (B)</p> Signup and view all the answers

At what interval should readings be taken after the first hour?

<p>30 minutes (D)</p> Signup and view all the answers

What action should be taken when the water level drops below the minimum depth for the hook gauge?

<p>Reset the readings by adding water (B)</p> Signup and view all the answers

How many points must be measured along the pond section to compute the average top width?

<p>Three points (D)</p> Signup and view all the answers

What should be done after each rainfall measurement using the rain gauge?

<p>Empty the measuring cylinder (C)</p> Signup and view all the answers

What is the primary purpose of conducting a performance evaluation using the ponding method?

<p>To compare actual water losses with design values (A)</p> Signup and view all the answers

Which term describes the downward movement of water below the ground surface?

<p>Percolation (A)</p> Signup and view all the answers

What is the role of the sealed section in the ponding method?

<p>To measure water losses over time (A)</p> Signup and view all the answers

What should be the initial water depth set in the pond at the start of each measurement?

<p>Approximately equal to the designed full supply level (B)</p> Signup and view all the answers

Which of the following scenarios can make use of the results from a performance evaluation using the ponding method?

<p>Maintaining water balance analysis (D)</p> Signup and view all the answers

What is the value of ∆H in meters?

<p>0.0376 (A)</p> Signup and view all the answers

What is the average length of the test section?

<p>10.8875 m (A)</p> Signup and view all the answers

What is the value of Vloss (volume loss) in cubic meters?

<p>0.3807141 m³ (D)</p> Signup and view all the answers

What is the value of (S & P)losses (seepage & percolation losses) in m³⁄s−m?

<p>3.1 × 10⁻⁶ m³⁄s−m (A)</p> Signup and view all the answers

The Rainfall column in the table represents what?

<p>The amount of rainfall during the test period (D)</p> Signup and view all the answers

What is the purpose of the Annex A section in this document?

<p>To present the test data collected. (C)</p> Signup and view all the answers

What is the most likely subject of this document?

<p>Performance evaluation of open channels (A)</p> Signup and view all the answers

What is the main objective of the test described in the document?

<p>To measure the amount of seepage and percolation from the open channel (B)</p> Signup and view all the answers

What is the role of the Technical Working Group (TWG) in this document?

<p>To establish standards for conveyance systems (A)</p> Signup and view all the answers

What is the minimum length of channel sections that can be considered for the Ponding Method?

<p>10 meters (D)</p> Signup and view all the answers

What type of material should the perforated stilling cylinder be made of?

<p>Gage 18 GI sheet (D)</p> Signup and view all the answers

What should be used to seal the ends of the selected test section?

<p>Metal plate or earth materials covered with plastic sheet (C)</p> Signup and view all the answers

How much of the channel depth should the pond and buffer zones be filled with water?

<p>80% of the channel depth (C)</p> Signup and view all the answers

Which conditions should be avoided when selecting channel sections for the Ponding Method?

<p>Bends and steep slopes (A)</p> Signup and view all the answers

What is the purpose of providing buffer zones around the test section?

<p>To minimize leakage of water across the embankments (B)</p> Signup and view all the answers

How should the stilling cylinder be installed in the test section?

<p>Laid flat on the channel bottom (C)</p> Signup and view all the answers

What tool is required to take measurements at the stilling cylinder?

<p>Hook gauge (B)</p> Signup and view all the answers

What is the seepage and percolation value for Sandy Clay Loam?

<p>2 mm/day (C)</p> Signup and view all the answers

According to the provided information, what is the recommended course of action if the actual seepage and percolation value exceeds the design value?

<p>Reduce water flow to account for the loss. (A)</p> Signup and view all the answers

What is the primary source of the seepage and percolation values presented in Table 1?

<p>Design Guides and Criteria for Irrigation Canals, O &amp; M Roads, Drainage Channels and Appurtenant Structures (n.d.) (D)</p> Signup and view all the answers

Which of the following researchers did NOT contribute to the provided bibliography?

<p>Johnson, T. (A)</p> Signup and view all the answers

What is the primary focus of the research presented in "Faulty Design Parameters and Criteria of Farm Water Requirements...?"

<p>The impact of faulty design parameters on irrigation system performance in Ilocos Norte, Philippines. (C)</p> Signup and view all the answers

Flashcards

What is a farm ditch?

A channel that carries irrigation water from the turnout to the paddy field.

What is percolation?

The downward movement of water below the ground surface.

What is a pond in the context of channel evaluation?

A sealed section created between earth embankments where combined seepage and percolation are measured.

What is seepage?

The lateral movement of water below the ground surface.

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What is the ponding method?

A method used to measure seepage and percolation in open channels by sealing a section and measuring water loss over time.

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PNS/BAFS/PAES 219:2017

A document outlining specifications and procedures for measuring seepage and percolation in open channels using the ponding method.

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Seepage

The leakage of water through the walls or base of an open channel.

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Percolation

The downward movement of water through the soil beneath an open channel.

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Ponding Method

A method involving filling the channel with water and measuring the rate of water level decline due to seepage and percolation.

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Bureau of Agriculture and Fisheries Standards (BAFS)

A government agency responsible for developing and promoting standards for agriculture and fisheries in the Philippines.

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Bureau of Agricultural and Fisheries Engineering (BAFE)

The agency responsible for agricultural and fisheries mechanization in the Philippines.

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Bureau of Philippine Standards (BPS)

An agency responsible for developing and promoting national standards in the Philippines.

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Open Channels

A specific type of open channels that are not covered or enclosed.

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Water Duty

The amount of water needed for a specific crop under certain conditions.

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Table 1: Seepage and Percolation Values

A table that lists the estimated seepage and percolation rates for different soil types.

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Leveling the Stilling Cylinder

Ensuring the stilling cylinder is level to prevent inaccurate water level measurements.

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Water Level Reading

The process of using a hook gauge to determine the water level within a stilling basin.

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Recording Water Level Readings

The practice of regularly recording the water level measurements and time stamp to track changes in water volume.

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Rainfall Measurement

The amount of rain that falls during the water level measurement period. It's crucial for understanding water balance in the channel.

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Comparable Readings

When three consecutive water level readings are relatively similar, indicating stable conditions in the channel.

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Water level change (∆H)

The difference in water level between the initial and final measurements in a ponding test.

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Average length (Lave)

The average length of the ponding section during the test.

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Average width (Wave)

The average width of the ponding section during the test.

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Volume loss (Vloss)

The volume of water lost due to seepage and percolation during the test.

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Seepage and Percolation losses (S & P)losses

The combined seepage and percolation rate per unit length of the channel.

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Time interval (∆T)

The time interval between two water level measurements in the ponding test.

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What is a suitable channel for the ponding method?

A long, straight channel with uniform cross-section and slope, used for studying seepage and percolation.

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Why seal the ends of the test section in the ponding method?

Metal plates or earth materials covered with plastic sheets are used to prevent water from entering or leaving the designated test section.

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What is the purpose of a buffer zone?

A buffer zone is a strip of land along the test section that helps minimize water leakage across the embankments.

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What is the purpose of the stilling cylinder?

The stilling cylinder is a perforated cylinder used to measure the rate of water loss in the ponding method.

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Where should the stilling cylinder be placed?

The stilling cylinder is installed at the middle of the pond, where the hook gauge is used to make measurements.

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How is the stilling cylinder installed?

The stilling cylinder is driven into the soil to minimize soil disturbance and ensure a stable level position.

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How is the water level managed in the ponding method?

The pond and buffer zones are filled with water to the normal operating capacity of the channel, typically 80% of the channel depth.

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Study Notes

Philippine National Standard for Conveyance Systems

  • Standard title: Conveyance Systems – Performance Evaluation of Open Channels – Determination of Seepage and Percolation by Ponding Method
  • Standard code: PNS/BAFS/PAES 219:2017
  • International Standard Classification (ICS): 65.060.35
  • Developed by: Bureau of Agriculture and Fisheries Standards (BAFS)

Scope

  • Specifies a method for determining seepage and percolation in open channels using ponding.
  • Results can be used to compare actual losses to design values, analyze water balance, and determine maintenance needs.

Definitions

  • Farm ditch: Channel carrying irrigation water from a turnout to a field.
  • Percolation: Downward movement of water below the ground surface.
  • Pond: Sealed section between embankments for measuring combined seepage and percolation.
  • Seepage: Lateral movement of water below the ground surface.

Principle of Ponding Method

  • A section of the channel is sealed at both ends with embankments and a plastic sheet.
  • The sealed area acts as a pond.
  • Water loss is measured as the change in water surface elevation over time in the pond.
  • The initial water depth is set to the designed full supply level.

Materials and Equipment

  • Perforated stilling cylinder (without bottom)
  • Hook gauge
  • Rain gauge
  • Plastic sheets
  • Stopwatch
  • Stakes

Site Selection

  • Sections must be 10 meters or longer, straight, and have consistent slopes.
  • Sections should be accessible for construction and measurement.
  • No other water sources should enter the section.
  • Avoid bends, steep slopes, and structures like valves, turnouts, gates.

Pond Construction

  • Remove debris from the selected channel section.
  • Avoid compaction of the canal bottom and banks.
  • Seal both ends of the test section with metal plates or earth covered by plastic sheeting.
  • Buffer zones of 1.5 meters are required at each end (refer to Figure 1).
  • Fill the pond to 80% of the channel depth.

Equipment Installation

  • One stilling cylinder for every 10 meters of the test section.
  • Install the cylinder at the middle of the pond and at a stable level for hook gauge measurements.
  • Use a wood plank and hammer to drive the cylinder into the ground to prevent soil disturbance, allowing 5 cm clearance between the rim of the cylinder and the normal water level of the channel.
  • Level the cylinder using a carpenter's level (refer to Figure 2).
  • Install a rain gauge adjacent to the pond (refer to Figure 1).

Measurements and Readings

  • Measure the length and width of the selected section after filling with water.
  • At 3 points in the pond, measure the wetted top width. Calculate the average width.
  • Determine the initial water level using a hook gauge.
  • Measure water level readings every 15 minutes initially, increasing to every 30 minutes after the first hour.
  • Record the amount of rainfall, as often as water level measurements are taken.

Computation

  • Calculate the change in water depth (ΔH = H – Hf)
  • Calculate the average pond length (Laverage = (Li + Lf) / 2)
  • Calculate the average pond width (Waverage = (Wi + Wf) / 2)
  • Calculate total volume loss (Vloss = (ΔH + R) × Lave × Wave)
  • Calculate seepage and percolation loss rate (see equation in document)
  • Calculate the percentage of seepage and percolation loss (see equation in document).

Application of Results

  • Compare computed seepage and percolation losses to design values, adjusting water duty if necessary (refer to Table 1).

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Related Documents

PNS/BAFS/PAES 219:2017 Conveyance Systems Performance Evaluation of Open Channels PDF

Description

This quiz tests your knowledge on the national standards governing seepage and percolation in open channels as mandated by the Bureau of Agriculture and Fisheries Standards. It covers key aspects such as the definition of terms, responsibilities of various agencies, and specific rules for standard development. Perfect for students and professionals in agricultural engineering and related fields.

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