National Standards for Seepage and Percolation

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Questions and Answers

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?

A mandatory requirement for compliance. Signup and view all the answers

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

It refers to a recommended option among several possibilities. Signup and view all the answers

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

Enhancement of Nutrient and Water Use Efficiency Through Standardization of Engineering Support Systems for Precision Farming Signup and view all the answers

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

Bureau of Agricultural and Fisheries Engineering (BAFE) Signup and view all the answers

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

Determining seepage and percolation in open channels using the ponding method. Signup and view all the answers

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

Measuring the length and width of selected channel section Signup and view all the answers

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

30 minutes Signup and view all the answers

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

Reset the readings by adding water Signup and view all the answers

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

Three points Signup and view all the answers

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

Empty the measuring cylinder Signup and view all the answers

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

To compare actual water losses with design values Signup and view all the answers

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

Percolation Signup and view all the answers

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

To measure water losses over time Signup and view all the answers

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

Approximately equal to the designed full supply level 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?

Maintaining water balance analysis Signup and view all the answers

What is the value of `∆H` in meters?

0.0376 Signup and view all the answers

What is the average length of the test section?

10.8875 m Signup and view all the answers

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

0.3807141 m³ Signup and view all the answers

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

3.1 × 10⁻⁶ m³⁄s−m Signup and view all the answers

The `Rainfall` column in the table represents what?

The amount of rainfall during the test period Signup and view all the answers

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

To present the test data collected. Signup and view all the answers

What is the most likely subject of this document?

Performance evaluation of open channels Signup and view all the answers

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

To measure the amount of seepage and percolation from the open channel Signup and view all the answers

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

To establish standards for conveyance systems Signup and view all the answers

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

10 meters Signup and view all the answers

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

Gage 18 GI sheet Signup and view all the answers

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

Metal plate or earth materials covered with plastic sheet Signup and view all the answers

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

80% of the channel depth Signup and view all the answers

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

Bends and steep slopes Signup and view all the answers

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

To minimize leakage of water across the embankments Signup and view all the answers

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

Laid flat on the channel bottom Signup and view all the answers

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

Hook gauge Signup and view all the answers

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

2 mm/day 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?

Reduce water flow to account for the loss. Signup and view all the answers

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

Design Guides and Criteria for Irrigation Canals, O & M Roads, Drainage Channels and Appurtenant Structures (n.d.) Signup and view all the answers

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

Johnson, T. 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...?"

The impact of faulty design parameters on irrigation system performance in Ilocos Norte, Philippines. Signup and view all the answers

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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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.