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🎓 Day 40: Module 4 & 5 Integration Mastery Quiz

Day 40: Modules 4‑5 Quiz – Masterpiece Edition | River Warrior

📝 DAY 40: MODULES 4‑5 QUIZ

⏱️ Estimated Reading Time: 25 Minutes | 🎓 Level: Professional Hydrographer

Test Your Knowledge – Advanced Processing, Volume, ADCP, Dredging & Sediment Mapping

Instructor: Engr. Rokib Hossain | River Warrior Academy


🏠 Course Homepage

🧠 Self‑Assessment Quiz

Click "Show Answer" to check each response. Use the calculator below to tally your score.

1. Module 4‑5 Quiz (20 Questions)

Covering Days 31‑39: Chart creation, volume calculation, advanced analysis, time series, bridge scour, SSS processing, sediment classification, ADCP, dredge monitoring.

🔹 1. What is the recommended grid cell size for IHO Order 1a in shallow water (<10 m)?

  • A) 2 m
  • B) 0.5 m or smaller
  • C) 5 m
  • D) 10 m
Answer: B (0.5 m or smaller) – For high‑resolution charts, 0.5‑1 m cells are typical. Smaller cell sizes capture features but require more cleaning.

🔹 2. Which gridding algorithm is recommended by IHO for robust bathymetric surface generation?

  • A) Weighted average
  • B) Nearest neighbour
  • C) CUBE (Combined Uncertainty and Bathymetry Estimator)
  • D) Kriging
Answer: C (CUBE) – CUBE incorporates uncertainty and rejects statistical outliers, making it the IHO standard.

🔹 3. What is the formula for discharge (Q) in a rectangular channel?

  • A) Q = width × depth
  • B) Q = velocity × area
  • C) Q = area / velocity
  • D) Q = width × velocity
Answer: B (Q = velocity × area) – Discharge = cross‑sectional area × average velocity.

🔹 4. In side scan sonar processing, what does slant range correction do?

  • A) Increases gain at far range
  • B) Converts slant distance to true horizontal distance
  • C) Removes electrical noise
  • D) Georeferences the image
Answer: B – Slant range correction removes the distortion caused by the towfish height, giving a true‑to‑scale ground range image.

🔹 5. Which sediment type typically produces the highest acoustic backscatter?

  • A) Mud
  • B) Silt
  • C) Sand
  • D) Rock / Gravel
Answer: D (Rock / Gravel) – Hard, rough surfaces reflect stronger acoustic returns.

🔹 6. What is the main advantage of using a moving‑boat ADCP over a stationary current meter?

  • A) Lower cost
  • B) Profiles velocity across the entire cross‑section quickly
  • C) Works in zero flow
  • D) No need for sound velocity
Answer: B – ADCP from a moving boat can cover a wide river in minutes, providing a complete velocity profile.

🔹 7. In a dredging contract, what is "over‑dredge allowance"?

  • A) Extra depth permitted beyond design
  • B) Minimum depth that must be achieved
  • C) Swell factor
  • D) Volume of wasted material
Answer: A – Over‑dredge allowance is a tolerance (e.g., 0.3 m) that may be excluded from payment or allowed for safety.

🔹 8. Which of the following is a valid method for ground‑truthing sediment classification?

  • A) Using only backscatter intensity
  • B) Grab sampling and grain size analysis
  • C) Single‑beam echosounder
  • D) Satellite imagery
Answer: B – Physical samples (grab, core) are necessary to calibrate acoustic classes.

🔹 9. What is the typical swell factor for sand dredging (in‑situ to loose)?

  • A) 1.00
  • B) 1.05‑1.10
  • C) 1.10‑1.20
  • D) 1.30‑1.40
Answer: C (1.10‑1.20) – Sand expands about 10‑20% after excavation. Exact factor depends on grain size and water content.

🔹 10. In bridge scour inspection, what risk level corresponds to a measured scour depth that exceeds the foundation depth?

  • A) Low
  • B) Moderate
  • C) High
  • D) Critical
Answer: D (Critical) – If scour depth > foundation depth, the bridge is at imminent risk of failure.

🔹 11. What does the acronym TPU stand for in hydrographic processing?

  • A) Total Pressure Unit
  • B) Total Propagated Uncertainty
  • C) Transducer Power Unit
  • D) Tidal Processing Unit
Answer: B (Total Propagated Uncertainty) – TPU quantifies the depth uncertainty from all error sources.

🔹 12. Which export format is preferred for archiving bathymetry with uncertainty?

  • A) GeoTIFF
  • B) JPEG
  • C) BAG (Bathymetry Attributed Grid)
  • D) PDF
Answer: C (BAG) – BAG stores depth, uncertainty, and tracking list per cell, ideal for archiving.

🔹 13. In a time series analysis of bathymetry, if the depth trend shows a slope of +0.2 m/year, what does that indicate?

  • A) Erosion (shallowing)
  • B) Deposition (deepening)
  • C) No change
  • D) Instrument error
Answer: B (Deposition / deepening) – A positive depth change means the seabed is becoming deeper (sediment added).

🔹 14. What is the minimum acceptable "percent good" for ADCP data?

  • A) 30%
  • B) 50%
  • C) 70%
  • D) 90%
Answer: C (70%) – Percent good >70% indicates reliable velocity measurements.

🔹 15. Which of the following is NOT a standard element of a hydrographic chart layout?

  • A) Scale bar
  • B) North arrow
  • C) Colour ramp legend
  • D) GPS satellite count
Answer: D (GPS satellite count) – Satellite count is acquisition metadata, not part of the final chart layout.

🔹 16. What is the purpose of a hillshade layer on a bathymetric map?

  • A) To show water depth
  • B) To highlight seabed relief and topography
  • C) To display tide levels
  • D) To indicate sediment type
Answer: B – Hillshade enhances visual perception of ridges, channels, and slopes.

🔹 17. In dredge volume monitoring, what is the typical frequency of interim surveys for a large project?

  • A) Once at the end
  • B) Weekly or monthly
  • C) Yearly
  • D) Never
Answer: B (Weekly or monthly) – Frequent interim surveys track progress and allow adjustments.

🔹 18. Which acoustic parameter is used to classify sediments in Qimera SonarClass?

  • A) Sound velocity
  • B) Backscatter intensity and derivatives
  • C) Water depth
  • D) Ping rate
Answer: B – SonarClass uses statistical features of backscatter (mean, standard deviation, skewness) to cluster seabed types.

🔹 19. What does the "Froude number" help predict in hydraulic engineering?

  • A) Scour depth around piers
  • B) Discharge measurement
  • C) Wave height
  • D) Sediment transport rate
Answer: A (Scour depth) – The CSU scour equation uses Froude number to estimate local scour.

🔹 20. When performing a moving‑boat ADCP discharge measurement, why are transects run in opposite directions?

  • A) To increase boat speed
  • B) To cancel compass misalignment errors
  • C) To avoid obstacles
  • D) To satisfy safety requirements
Answer: B – Opposite transects average out heading/compass biases, improving accuracy.

📊 Interactive Score Calculator

Enter the number of correct answers (out of 20) and see your rating:

Correct answers:

Rating: --

18‑20 = Expert | 15‑17 = Proficient | 10‑14 = Review needed | <10 = Re‑study Modules 4‑5

2. Answer Key Summary

QuestionCorrect Answer
1B
2C
3B
4B
5D
6B
7A
8B
9C
10D
11B
12C
13B
14C
15D
16B
17B
18B
19A
20B
🎓 Scoring: 18‑20 = Expert Hydrographer, 15‑17 = Proficient, 10‑14 = Needs Review, <10 = Re‑study Days 31‑39.

3. Recommended Resources for Review

4. Action Items & Next Steps

  • 📌 Review any questions you missed by revisiting the corresponding day.
  • 📌 Share your score in the comments and challenge fellow hydrographers.
  • 📌 Proceed to Day 41: Sub‑Bottom Profiling Introduction.
© River Warrior – Day 40 of 100‑Day Hydrographic Mastery | Masterpiece Edition | Home

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