Interview with Prof. Dong-Jiing Doong, Department of Hydraulic and Ocean Engineering, Coastal Ocean Monitoring Center at the National Cheng Kung University (NCKU). NCKU together with the governmental Water Resources Agency (WRA) are partners in the RECONECT project.
Weather extremes in Taiwan
Floods are a serious problem in Taiwan. Surrounded by sea, the island is vulnerable to typhoons, tropical storms that bring extreme rainfall events with them. In 2009 the typhoon Morakot broke records by dumping over 2,500 millimetres of rainfall in three days on parts of southern Taiwan, causing extreme damage. In comparison to rivers around the world, rivers in Taiwan have the steepest slopes, the largest discharge per unit drainage area, and the shortest time of concentration. Rapid urbanization without proper land use management usually worsens the flood problems. Consequently, flood hazard mitigation has become the most essential task for Taiwan to deal with.
Governance of flood risk mitigation
The Water Resources Agency (WRA) is the administrative agency of the Ministry of Economic Affairs of Taiwan and responsible for water-related affairs. WRA has devoted a great effort to flood defence structures, such as levee construction, dredging, flood diversion, flood detention, as well as improvements in watershed management and drainage. Billions of US dollars have been spent on flood works, especially on building river levees. Most of these structures had been constructed prior to the 1990s. Although the water authority keeps maintaining the existing flood structures and builds new ones, the flood damages are growing, instead of decreasing. In recent years, the approach for flood reduction and prevention efforts expanded to introducing non-structural efforts, such as flood alert and warning systems.
Status of Nature-Based Solutions in Taiwan
Flood risk mitigation takes place along three lines of defence: rivers, urban areas, and coast lines. With regards to rivers, measures that fall under the umbrella of Nature-Based Solutions (NBS) are mainly focused around the creation of more space for rivers and re-allocation of flood zones. The most popular way to store water during rainfall periods are detention basins, including both natural and artificial ponds. There are more than 1000 detention basins across Taiwan (Figure 4 — 5). Urban NBS include Green Roofs, Porous Pavements, Rainwater Harvesting and Vegetated Swales. All of those measures have recently started to be promoted, and can today only be found regional and on a small scale. The status of working with nature for protection of the coast line is similar; only recently pilot assessment started to be carried out, investigating the benefits of planting mangroves for coastal protection.
Drivers for Nature-Based Solutions
With recent economic growth and increasing awareness of environmental degradation, public demand for building with nature increases. Infrastructure is expected to not only protect against flood risks, but to also have aesthetic and recreational value. However, the defining driver for any flood risk mitigation effort is the effectiveness and ability to withstand a typhoon.
Challenges for upscaling Nature-Based Solutions
The main barrier for NBS is the availability of land. Publicly owned land can be used for small scale NBS, however Taiwan is well developed, with large percentages of accessible land in private property. The value of land and property prices is constantly increasing. Selling or transferring land for the purpose of e.g. a retention basin is therefore unattractive to land owners, especially in urban areas. Compensation schemes most often are not able to provide sufficient incentive for conversion of land use. However, some land is being affected by seawater which means it has limited usability and can be used as a detention basin.
A second challenge lies within the political arena. There is stagnation around agreement on projects and strategies for investments. Technical solutions are debated in a non-technical, contested political dispute which can hamper the structural implementation of e.g. NBS for flood risk mitigation. On the other hand, immediately after a typhoon or flooding event, there is a high level for support for proposed measures on flood protection including the use of NBS. But the more time passes after such an event, the more difficult it gets to achieve a consensus on ways ahead.
Regional stakeholder collaboration
Advancing the implementation of NBS involves stakeholders ranging from land owners and village chiefs to the science community and government institutions. There is limited support from the international community for regional collaboration. Therefore, all funds must come from the national government. There is knowledge exchange with academic institutions in Japan, Thailand, Vietnam and Indonesia around the topic of NBS as WRA is interested in approaches outside of Taiwan. Engagement in the RECONET project allows WRA to see how NBS is being implemented in other countries and what can be applied in Taiwan. For example in May 2019, WRA decided to work with the NCKU to assess potential sites at the coast for application of NBS.
“At the National Cheng Kung University (NCKU) we work on the theoretical and fundamental research for flood mitigation and flood warning systems. The governmental Water Resources Authority (WRA) comes to the university for technical support, such as simulations of urban areas affected by flooding.”
A Dutch RECONECT partner (IHE) will be part of this assessment. Both NCKU and WRA are interested in identifying real tangible outcomes from building with nature and WRA has the possibility to fund the NCKU for activities that lead to these outcomes, whereas normally the budget is restricted to fundamental research.
If only NCKU would have joined RECONECT, the project outcome would have been only one report at the end, but through WRA much more concrete impacts are possible.
Application and upscale of approaches developed in RECONECT
The defining criteria for any application of NBS are whether or not they can withstand against extreme weather events like typhoons. After vast destructions through typhoons in the recent past, the public does not have a lot of trust in solutions that promise to mitigate risks.
“It is our important task to support WRA to convince the public and parliament that these NBS are the right solutions to apply.”
For the applications of NBS in the coastal area of Taiwan, the NCKU is going to work on the assessment of using mangroves to reduce the wave/storm surge impacts to the coastline. Further, the removal of the less-used fishing harbours in order to recover natural coasts is investigated. Through RECONECT the results of those assessments are shared with partners, and in return new ideas and experiences are learned from partners. WRA is thereby also looking for RECONECT partners that apply new NBSs for urban flooding mitigation.
The European regulatory framework with regards to environmental management is in several aspects further advanced and defined than in comparison to regulations in Taiwan. There is potential to upscale insights from RECONECT project outcomes in guidelines and regulations and WRA is very interested in these result areas.
Key messages
Through small scale initiatives we know that NBS can bring benefits. The important question in Taiwan is if NBS can survive during typhoons. Through RECONECT we are looking for such answers over the next four years.
