Coral reefs are degrading across the entire Great Barrier Reef. Rehabilitation of the Great Barrier Reef is crucial for Australia, both socially and economically because it provides $6 billion in revenue and 63,000 jobs. The Queensland state government issued a challenge within the "Small Business Innovation Research" program to quickly restore ecological functions provided by the reef. Van Oord and CSIRO participated in this challenge by testing a concept designed to scale-up rehabilitation efforts. This concept involves rehabilitation of the reef by increasing the number of larvae deployed onto the reef. To achieve this, coral-spawn slicks should be collected from areas with healthy coral populations that show a redundancy of embryos. During transport, these slicks should then be stimulated to grow into settlement competent larvae. Subsequently, they can be deployed at a degraded coral reef. The collection phase should be executed with pumps to reach considerable volumes of coral embryos for significant ecological scale. Unfortunately, the mortality rate of coral embryos due to pumping is so far unknown, yet crucial to determine. Therefore, the objective of this research is to develop a method for designing a pumping system that can pump coral embryos and larvae into a vessel-based container or hopper with maximal survival rates.
To achieve this objective, the strength of coral embryos and larvae as well as the stressors in a pumping system are investigated. In order to design and optimise the pumping process for survival, it is useful to have a framework that estimates the balance between strength of coral embryos and larvae and stressors. In literature, comparable strength and stress balances are known in, for example, thermal stress onto corals. The cause of failure (or mortality) is a combination between the strength, the exposed stress (or load) for a certain period of time and the capability to regain strength. Failure happens when the strength cannot withstand the stress (or load). These failure effects are also described through threshold limit values (TLV) which indicate a limit that the stresses may not exceed. Examples of such limits are time weighted average, short-term exposure limit and ceiling limit. Within the design of a pumping system, these values are expected to be acute (e.g. in the pump) and chronic stress (e.g. in the pipeline). In order to distinguish between pumping systems, the stressors in the system can be calculated by using tools such as a mathematical model.

The coral life cycle commences with gametes that contain eggs which are fertilised in the slick at the ocean surface, before developing into embryos. Because the buoyancy of coral embryos is positive until 36h following spawning, dispersion is limited. Hence, they are easiest collected within this period of time. The pumping related strength of coral embryos and larvae is therefore investigated in this research. The assumption is made that the strength of the embryos and larvae differ in the first period following spawning. In order to gain insight in the strength limits of coral embryos and larvae within this period, strength tests are executed. During the mass-spawning event in November 2018, fertilised eggs were collected and used in a Couette-rheometer test at the Heron Island Research Station. These tests consist of a cylinder rotating at different speeds in a container filled with water and embryos. Due to the rotation of the cylinder, the coral embryos and larvae experience stress. The living coral embryos are counted before and after each experiment by use of a microscope experiment in order to define the survival rate. After 5-7 hours the embryos have developed a considerable strength (larger than can be applied by the Couette-Rheometer). Therefore, it is recommended to start the collection process after 5-7 hours following spawning. Nevertheless, the tests do not define the exact strength of the embryos. Hence, it is advisable to investigate the exact strength in further research.

To design a pumping system that can pump coral embryos and larvae with low mortality, the stressors in the system should be minimal. The main technical criteria of the pumping system include low shear stresses, low-pressure fluctuations and low flow accelerations. Practical criteria such as availability, scalability and handling should also be considered in the design. A mathematical model was designed to calculate the previously described factors by calculating the magnitude of the stressors in a pumping system. Based on the model, it can be concluded that the pipeline configuration of a coral slick collection system should contain minimum pipe length, maximum diameter, minimal surface to encounter (e.g. bends and connections), low rpm and flow velocities and submerged in- and outflows openings.

Laboratory tests in the Netherlands and field tests in Australia have been executed in order to validate the relation between the strength of coral embryos and larvae and stressors in a pumping system. During laboratory tests, pumping system aspects that contribute most to damage have been investigated, and potential practical issues have been identified. Damage rates were estimated for different pumps and pipeline configurations using different proxies such as, hydrogell balls, peas, berries and fish eggs. From these tests, the Hidrostal and Diaphragm pump resulted in low damage rates and were selected to be applied during the field tests. Additionally, a skimmer (intake) to collect the floating particles was designed and tested, both in the laboratory as well as the field.

The field test has been executed in the Southern Great Barrier Reef around the Heron and Wistari reef. Currently, this part of the reef boasts the highest level of coral cover throughout the entire reef, and is almost at its historical maximum. Therefore, it was chosen as research location because of its expected large supply of coral spawn. The main goal of the field study was to investigate the possibility to pump coral embryos following the mass spawning in November 2018. The experimental setup consisted of a tug vessel with two pumping systems, each with a different pump (i.e. the Hidrostal and Diaphragm pump) and the same configuration. A total of total twelve tanks was used for cultivation of which six plastic and six steel. The total number of living coral embryos that have been pumped was approximately 29 million from which 19% developed into competent larvae within five days. The competent larvae were pumped through the same system to investigate their survival rate, which was around 88%. This indicates that deployment of larvae onto degraded reefs should be possible by pumping without much loss and that coral larvae are less fragile compared to coral embryos.

The objective of this research was to develop a method for designing a pumping system that can pump coral eggs, embryos or larvae, from the sea surface onto a vessel housing an aquaculture facility. By using the previously described criteria, it is concluded that coral embryos and larvae are able to survive pumping related stressors. Further research should aim to find the exact strength of coral embryos after which a more precise model can be created to estimate mortality. Furthermore, limitations for pressure differences should be determined. For now, the assumption is made that for designing a pumping system, atmospheric pressure should be the minimum local pressure which is conservative. Additionally, the controlled deployment of the competent larvae onto degraded reefs should be further investigated because this project was not focused on that phase. To conclude, the project needs up-scaling towards hopper sizes, with a broader range of coral species and various weather conditions.

Given the previous described challenge, this research proofs that it is possible to pump coral embryos, after which they can grow into competent larvae and be deployed onto degraded reefs. Significant quantities of new recruits can be collected at healthy reefs and by using hopper size vessels, the collection of coral embryos from slicks become promising.
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Shock Safe Nepal was founded as a response to the 2015 Nepal earthquakes to function as a platform to contribute to the development of knowledge on earthquake safe housing. The goal of the report of team 5 is to validate and optimise the design of the pilot house that was created based on the work of previous teams, and the development on implementation plans for a validated and optimised house. Literature study, field work and interviews have been performed resulting in main findings of this report.
Primarily, the used materials were analysed in the report, including bamboo, CSEB bricks and concrete. They were analysed consulting literature, conducting laboratory tests in cooperation with the University of Tribhuvan. Bamboo was mainly analysed consulting literature sources, since laboratory tests were not feasible. It was found that its material properties are immensely difficult to determine and can vary from one column to another. However, it remains a strong and cheap building material. CSEB bricks were used due to its availability, strength and price. The material properties were derived from tests done by Build Up Nepal and from literature sources. Its mechanical performance is like that of concrete. It’s an easy material to build with and incorporate steel rebar’s. However, its durability and consistency is something which was not thoroughly investigated and remains debatable. The concrete used, was thoroughly tested, conducting slump cone, compression and Schmidt Hammer tests. It was found that the concrete used in the pilot house is of acceptable quality, but there is room for improvement by following clear guidelines and technical assistance. Subsequently, static calculations were executed, regarding the roof, the load bearing structure and the foundation. It was found that these different components, perform safely under static conditions, with the applied loads, separately and combined. The load bearing structure has turned out to be a wall-bearing structure. This was not assumed at first. Furthermore, after calculations, it was found that the roof and foundation were largely over dimensioned. This is, however, determined considering many assumptions, such as the soil properties.
Regarding an earthquake situation, the walls and bearing capacity were researched and calculated following quasi-static conditions. The earthquake conditions were derived from the Peak Ground Acceleration. Primarily the walls were researched. Two scenarios were considered, a 3-point collapse failure mechanism and punctual overturning collapse failure mechanism. Both mechanisms were tested for different wall compartments. These calculations give a small insight in the actual situation, because dynamic loads are applied statically, non-linear or dynamic calculations should be conducted as well as FEM modelling, for more thorough understanding. It must be said that the rebar and resonance effects were not considered. Regarding the bearing capacity, a PGA of 0.6 was used and from calculations, partly considering the soil and superstructure inertial effects, the bearing capacity would not fail. However, superstructure resonance was not considered. Larger PGA’s were not investigated, which means that it is not determined under which conditions failure would occur. From these analyses the Structural optimisations are made to the design. This includes improving the joints between different elements of the house. Regarding the materials used the optimisations include 5 protecting the CSEB bricks from weather as they are load-bearing. Guidelines are given on the placement of the house regarding the foundation and the slope. According to the calculations the foundation is over- dimensioned.
For the stakeholder analysis, extensive research was done through interviews which was combined with literary information available. This was then used to create a power interest grid and a network analysis, which shows the links between different categories of stakeholders and different specific stakeholders. This analysis also gave insight in the sheer number of stakeholders involved in rebuilding Nepal and the importance of defining the role of SSN further. The external factors that are important in working in Nepal were analysed, this was done regarding social, technical, economic, environmental, political, legal and ethical aspects and based on literature research, field research and interviews. Implementation methods of different types of organisations in Nepal were analysed. These findings were concluded in a SWOT analysis of the organisations. Defining the strengths, weaknesses, Opportunities and threats of other organisation help to define the direction that SSN should move in and those aspects of building in Nepal that can also be defined as strengths, weaknesses, opportunities and threats to SSN or make SSN different to other organisations. The risks of building in Nepal must be considered to create a realistic and feasible long-term plan and need to be mitigated a risk analysis is done. The findings in the risk assessment are found in external risks, design risks and construction risks. A plan is then set up to mitigate external risks and construction risks are the. The findings of the long-term plan are organised into a strategy for SSN, an engagement plan and an implementation pathway. The strategy is concluded in a SWOT analysis which is then used to create a TOWS analysis. This TOWS analysis combined the internal and external strengths and weaknesses to bring new creative ways of maximising strengths and opportunities and minimising the weaknesses and threats. The Implementation pathway contains long- term goals for SSN, that are structured into regulatory, implementation, technical and organisational goals and that can be added onto by future teams.
This research is to be a logical step in a series of research projects which will contribute to the reconstruction of an earthquake safe environment in Nepal. It can be used as consultation advice, guideline or as a base for in-depth follow up research on one of the included topics. ... Read more