Island-based catchment-The Taiwan example

Chen, C. T. A., et al., 2004. Regional Environmental Change

Original research (primary data)
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Rapid economic and industrial development in Taiwan over the past five decades has elevated the island’s standing and earned it a place in the group known as the Four Small Dragons of Asia. Such growth, however, has been at the expense of the environment. There are currently nearly 23 million people juggling for space on the small island of 35,873 km(2). Aggravating the matter further, the central mountain ranges and hills take up 73.6% of the land area with some 156 peaks surpassing 3,000 m. As a result, most people live in coastal plains which amount to only 9,490 km(2). Pressure to move people inland has led to road construction and deforestation, both of which have contributed to an already high denudation rate of topsoil. As a consequence of this, thirteen rivers in Taiwan are now ranked among the top 20 worldwide in terms of sediment yield. Aside from this, the frequency of both floods and droughts increased prior to 1990, perhaps because of deforestation and global warming. Fortunately, the new conservation-orientated forest management policy of 1991 has alleviated the problem, somewhat, and the occurrence of floods and droughts has since decreased. The problem of water shortage, however, has worsened because of the warming trend in atmospheric temperature. Damming may ameliorate the water shortage problem but may affect the shoreline stability, as well as the ecology and water quality in the estuaries. Furthermore, these detrimental effects may go far beyond the estuaries, and even fisheries on the continental shelves may be affected.

Case studies

Basic information

  • Case ID: INT-117-1
  • Intervention type: Management
  • Intervention description:

    Conservation-based forest management - decrease harvested volume of timber

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Reduced water availability  Unclear results Projected annual discharge of 100-yr drought
    Freshwater flooding  Unclear results Projected annual sediment discharge of a flood of 100-year return frequency
  • Approach implemented in the field: Yes
  • Specific location:

    Kaoping River watershed

  • Country: Taiwan
  • Habitat/Biome type: Tropical and subtropical forests |
  • Issue specific term: Not applicable


  • Notes on intervention effectivness: effectiveness results unclear because they do not attribute impact to the intervention but rather that it coincided with the change in reduced flood frequency and drought. "Interestingly, the frequency of floods and droughts before 1991 both increased, but since enactment of the order, both have noticeably declined."
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures:
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: No
  • Experimental evalution done: Not applicable
  • Non-experimental evalution done: Empirical case study
  • Study is systematic: