Accidental breaches do not happen often. But when they do, hydraulic engineers must know what to do, and react fast and smartly. This practical course will teach you to prepare a safe and solid plan to get a gap closed, both in case of emergency as well as in case of a pre-planned operation.
Closing a gap in a breached dike or closing a tidal inlet seems simple in first instance but, in fact, many closure works fail just before completion. During the closing process the velocities in the gap increase considerably, leading to unforeseen complications. This has happened for example with a number of emergency closures in the Yangtze River in 1998, and along the Oder in Germany in 2002. But also the planned closure of the Miele estuary in Germany was complicated by exactly this problem.
In case of emergency closures, action is often taken based on panic. Very often these actions aggravate the situation, instead of resolving it. For planned closures of inlets the time pressure (and panic) by virtue is less, but as these works are often bigger and more comprehensive, mistakes can have a huge impact and lead to risky situations.
Understand hydraulic processes
Hydraulic engineers confronted with closure works (either planned or in case of emergency) have to understand the hydraulic processes occurring during a closure. And they have to know what kind of actions should be undertaken given the hydraulic conditions of that moment. In most cases public opinion stresses to put "things" in the closures gap but this usually worsens the situation; velocities increase in an uncontrolled way. Before starting the final closures one should define the best location (usually somewhat inside the gap, because there velocities are lower and depth is less) and protect the bed at that location to prevent uncontrolled scour in the final phase. With relatively simple tools this can be done. In this course, we will present and discuss these tools and provide a number of exercises to train their use.
By the end of this course, you will be able to design a simple closure work and to set-up the detailed programme for the design of a more complicated closing work. For emergency closures you will be able to take the appropriate steps leading to a successful closure on short term. For planned closing works you will be able to make a detailed plan and select the optimal closing strategy. You will be able to draft the detailed requirements for the contractor.
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Week1: introduction and positioning the subject
Overview of different types of closures, the relevance of the topic, differences between emergency closures and permanent closure works.
Week2: use of theory and data collection
Overview of hydraulic calculations, the hydraulics of flow through gaps, required data to be collected for closure works, like bathymetry, tidal data, wind data, geotechnical data.
Week3: design practice of closure dams, rock closures
General methodology of closing work, calculation of required rock sizes using a very simple storage/area method.
Week4: design practice of closure dams, caisson and sand closures
Design details for closing an gap with only sand or using box caissons as well as sluice caissons.
Week5: Scour, filters and construction method
In case of closing a gap in a sandy bottom, bed protections are vital in order to prevent scour holes endangering the closure work; in this part the design of bed protection works will be elaborated.
Week6: Final design exercise
The participants may select an exercise from a list or suggest a location themselves. At that location a preliminary design for a closing has to be made using real boundary conditions.
In the last week of the course all participants have to do an individual design exercise. The participants may select from a number of options, including both emergency closures (repairing dike and levee breaches) as well as permanent closure dams (e.g. of a tidal inlet). This assignment will be individually assessed on basis of this final design a mark will be given. For a certificate a sufficient mark is required.
Literature & Study Materials
A prerequisite for this course is knowledge of hydraulic engineering and tides. Many good textbooks on this matter exist. For tides one may study "Waves, tides, and shallow-water processes" by Open University isbn: 9780080363721. The textbook for this course will be made available to the participants as pdf and/or ePub. Also a printed version of the book will be available on short notice.
Read a chapter from the course book "Closure Works", which gives an introduction to this field (full version of the book will be given during the course)
If you successfully complete this course you will earn a professional education certificate and you are eligible to receive 3.0 Continuing Education Units (CEUs).
This course is primarily geared towards working professionals. There are no formal admission requirements, but it is assumed that sufficient knowledge about hydraulic engineering is present. Especially a basic knowledge of tides is essential.
In order to complete your admission process you will be asked to upload the following document:
- a copy of your passport or ID card (no driver's license)
If you have any questions about this course or the TU Delft online learning environment, please do not hesitate to contact us by sending an email.