Soil and Water Conservation
Promoting Regeneration of Rural Villages
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Conservation Strategies Response to Climate Change for the Key Watersheds

Abstract

Climate change has caused several catastrophic events such as landslide, debris flow, flood, and the decreasing in agricutural products and biodiversity in Taiwan. Three hotspot watersheds have been selected including Puzih River, Chishan River and Sindian River by using the variation of moisture index and then coupled with long-term meteorological data, satellite images, and digital elevation model to discuss the relationship between climate change and the variation of vegetation, the potential disasters of slopeland roads and the flood-prone areas in the first-year’s project. The delineation of potential disaster and environmentally sensitive areas, the soil and water conservation, the green environment creation, the watershed management and index of conservation benefits are all explored in the hotspot watersheds to make the adaptation strategies in response to climate change during this year. The results of this second-year’s project are mainly described as the follows:

For the Puzih River watershed, there are three management areas extracted using curve number, and there exist five and eight depression sites in the A and B management area respectively, which can be further determined the priority of planning sites using criteria of detention volume and watershed area, and accoding to diffrernt scenarios of climate change, the change of peak flow could be up to 86.72%. For the Sindian River watershed, landuse status of 1995 and 2008 was applied to simulate the benefits of placement of vegetated buffer strip and to analyze the concentration of pollutants and nutrients such as BOD, TP, TN, and NH3 in the four hotspot sub-watersheds. For the Chishan River watershed, the accuracy of the potential landslide could be greater than 70%, both using eight environmental indices and five potential indices of the watershed landslide. Analysis of vegetation recovery rate shows that there is a good vegetation recovery in the watershed landslides except the upstream areas.

This study integrates results of this two-year’s project and provides suitable conservation strategies in response to climate changes for the selected wateraheds. For flood-prone areas, it should have the concept of risk diversification which can be operated by constructing the fram pond on suitable depression sites and had better replace the concepts of flood detention to flood storage. For potential drought areas, the related authorities should place enough width of vegetated buffer strip to prevent agricultural non-point source pollution and maintain a high level of water quality. For potential landslide, there shuld be man-made recovery of vegetation in landslide areas which would affect the protected targets and quantify the potential disaster along the roads for easy to manage. An educational training program was also held to enhance the trainees understanding the topic of strategies of soil and water conservation in response to climate change. The follow is conservation strategies response to climate change for the key watersheds:

Conservation Strategies Response to Climate Change for the Key Watersheds
Items Puzih River watershed Sindian River watershed Chishan River watershed
The first step
(strategies of disaster prevention and hardware structure)
Strategies of disaster prevention: Above all is emergency strategy, please refer to the measures of disaster prevention compiled from Ministry of the Interior
Strategies of hardware structure: Please refer to handbooks of soil and water conservation.
The second step
(software measures and conservation strategies)
  1. Series of detention dams are recommended at the depression site located at the upstream.
  2. The topographic depressions in the slope farmland are the suitable places to construct the farm ponds.
  3. Riparian and wetland area are recommended to construct multifunctional facilities of water storage by diverting the channel peak runoff for the purposes of mitigation under torrential rains.
  1. Non reservoir area: Necessary facilities of water storage are prior to be selected from the hotspots of depression sites with the functionality of water resources.
  2. Reservoir area: To screen the hotspots of highly agricultural development, and place the vegetated buffer strips nearby the riparian areas are required to reduce the effects of agricultural non-point pollutants on water quality.
  1. To withdraw and settle down the secured targets affected by landslide.
  2. The areas with traffic convenience and secured targets show difficulty in natural vegetation succession are recommended to adopt the vegetation engineering for revegetation
  3. The steep areas with no secured targets should be recovered by natural succession.

Keywords: Climate change, Environmental index, Risk assessment, Environmentally sensitive areas