The aim of this thesis is to introduce the mechanism ofstreamer process in dielectric liquids. The appearance of bushlike streamer shape firstly and then a tree structure later hasbeen given an interpretation and meaning. Also, the change ofstreamer velocity from tens of meter per second to severalkilometer per second, starting from bush like shape, treestructure, till complete breakdown has been introduced. ThesepreVIOUS stages have been studied on an energy balanceconcepts, from low applied voltage to high voltage values. Thelength of streamer also is studied and a model to estimate it hasbeen derived.When a high voltage is applied to a dielectric liquid inpoint plane configuration, a dark tiny branches spread out inmany direction outward from electrode tip toward planeelectrode. These tiny branches called bush like streamer. Thebreakdown criterion in dielectric liquid, in this thesis, is thecondition when the liquid zone around high voltage electrodetip (about five times of the bush branch radius) has beenevacuated and replaced by air. The number of branches whichshould fill this zone and empty it from liquid is 25 brancheswith 8 urn radius. This number of branches is considered asbreakdown index for dielectric liquids. According to energybalance concept; one branch channel in bush like streamer tobe initiated (41lm radius), the pressure inside it should begreater than the surrounding pressure. The required criticalelectrical field which achieves this condition is 2.18 MV/cm.when the applied voltage increases again, the tree streamerstructure appear as a tube emanated from bush like zone towardthe opposite electrode. Under the energy balanc~ concept; thereasons, including: damaged pipe materials, poor pipe connections,misalignment and depth fluctuations of collectors and laterals duringinstallation, pipe sedimentation, and lack of envelope.A quality control and quality assurance system for subsurface drainageprojects was developed to improve their quality. A questionnaire wasconducted within Egyptian Public Authority For Drainage Project (BP ADP) toanalyze the current construction practices and the four phases of the project.The four phases are as follows: Field Investigation phase, Design phase,Tendering and Construction phase, and Operation and Maintenance phase. Thespecifications and standards of each phase and the main control points weredetermined. A linear responsibility matrix was developed for each phase. Afterthat, the weakness points and the required corrective actions were alsodetermined for each phase.The results showed that, the low quality of subsurface drainage systemconstruction is attributed to the lack of adequate aspects of quality control andquality assurance for the four phases of the project. To improve the qualitycontrol and quality assurance for the project, it is important to concentrate onthe main control points of each phase and apply the required corrective actions.