Determination of Tile Drain Discharge under Variable Hydraulic Conditions

Daniel Szejba,Sławomir Bajkowski

doi:10.3390/w11010120

Abstract

The aim of this study was an investigation of tile drain flow velocity under variable hydraulic conditions and of tile drain discharge using an ultrasonic flow meter. There is an essential variance between velocity values measured by an ultrasonic flow meter and reference values determined by a laboratory method. Differences result from specific measurement conditions, which appear in drainage pipe systems. The values of velocity measured by ultrasonic flow meters were higher than the reference values for three examined flow phases: Free, transient, and pressured flow. The discharge from a tile drain working on a partially filled up pipe in no-pressure conditions should be calculated by an adapted equation based on the California pipe method, whereas the discharge from a completely filled up drain pipe working over pressure should be calculated as a ratio between 0.428 times the measured velocity and the pipe cross-section area.

Highlights

Subsurface drainage is an important water management practice on naturally poorly drained soils and is designed to lower the water table to prevent waterlogging and flooding and to maintain agricultural crop productivity [1,2]
Because a control section has different hydraulic conditions compared to the recommended pipe control has different compared to the thedetermination recommended for areaBecause velocity,athe water section level and flow velocityhydraulic measured conditions by area velocity required for area velocity, the water level flow velocity measured by area velocity required the ofpipe calibration curves or the elaboration of and formulas, which enabled the measurement of values with determination of calibration curves or the elaboration of formulas, which enabled the measurement respect to the reference values
Andifferential essential pressure transducer of an AV probe is characterized by good accuracy and precision of variance between the measured AV velocity values and the reference values controlled by a laboratory measurement

Summary

Introduction

Subsurface drainage is an important water management practice on naturally poorly drained soils and is designed to lower the water table to prevent waterlogging and flooding and to maintain agricultural crop productivity [1,2]. Removal of excess water accelerates drying of the soil at the beginning of the growing season, which enables the preparation of the soil for planting earlier, lengthening the growing season. It provides traction for farm equipment and mechanical strength to reduce compaction [3]. Tile drainage systems are most often installed in low-hydraulic conductivity soils, such as clays or silty clays. These kinds of soils are characterized by the preferential flow phenomenon which can lead to fast water and solutes flowing into the drainage system.

Objectives

Methods

Results

Conclusion