Determination of Tile Drain Discharge under Variable Hydraulic Conditions

Round 1

Reviewer 1 Report

The test problem is very important to assess the flows in drainage networks. The work is very interesting and concerns an investigation of tile drain flow velocity under variable hydraulic conditions, as well as the determination of tile drain discharge using an ultrasonic flowmeter. The authors showed significant differences between velocity values measured by ultrasonic flow meter  and reference values controlled by the laboratory method. Differences result from specific  measurement conditions, which appear in drainage pipe systems. 

My basic remarks to the paper:

·         Literature review is correct and contains basic items. However, there is a lack of in-depth review of various methods for measuring the flow rate in pipes. With reference to the advantages and disadvantages of these methods. And the scope of their use.

·         In the chapter 2 Materials and Methods, the authors correctly described the research problem and methodology of laboratory measurements. They also point to basic research problems: „The problem with a drainage pipe is its relatively small diameter, low flow and insufficient water level for AV  measurements during some parts of the season. Previous research has shown that discharge measurements by control section with the same diameter as a drainage pipe (75 mm) were characterized by poor accuracy, especially for zones of very low and high discharges.” However, it is difficult to understand why in the Results section, the average velocity in pipes are analyzed. They were determined after all on the basis of the drain discharge and water level. And these values are directly measured. Please explain it in more detail! This requires determining the purpose of doing such a velocity analysis.

·         Analysis of the weir located at the end of the pipe is quite problematic. In Formula 1 does not account for the Submerged Sharp-Crested Weir. Looking at the schemes, these weir are submerged!

·         The use of such weirs in practice causes deposition of sediment of the pipe.

Author Response

Author Response File: Author Response.docx

Reviewer 2 Report

The merits of the reviewed paper is correctly and it is hard to have any reservations to content-related correctness of the presented analysis as well as to the received results (also the statistical processing is sufficient). Regarding linguistic a spect of the article, the scientific issue was presented in a clear and understandable way. English language is correctly and acceptable as well as used professional terminology, however, it requires some minor corrections in punctuation and spelling e.g.:

1) Page 5, Line 9 ("Results and Discussion"): formulas - formulae

2) Page 4, Line 4 ("Materials and Methods"): There is "transient flow - submerged flow". It should be "transient flow - submerged weir"

3) Page 4, Line 5 ("Materials and Methods"): There is "pressured flow - submerged flow". It should be "pressured flow - submerged weir"

4) Page 9, Line 31 ("Conclusions"): The "Ing." is short for "Engineer", so there should be "Eng."

Author Response

Author Response File: Author Response.docx