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|標題:||Water conservation hotspots selection at the Dadu Plateau by using index of land cover changes
|關鍵字:||Land cover;Water conservation;Hotspots;地覆類別;水源涵養;熱點區位||Project:||水土保持學報, Volume 49, Issue 1, Page(s) 1979-1994.||摘要:||
The Dadu Plateau with gentle slope and near urban areas has been urbanized rapidly, which increases the impervious surface and reduces infiltration. In addition, the areas of forest land are easily changed into grass land due to periodic wildfire in dry seasons. These changes cause the decrease of water storage capacity in the Dadu Plateau. How to quickly monitor land cover change and effectively 1 sieve the water conservation hotspots is a crucial issue for flood control. In this study, Normalized Difference Vegetation Index (NDVI) derived from four seasons’ satellite images is applied to classify the land cover of the Dadu Plateau. However, the categories of grass land and farm land could hardly be distinguished precisely with satellite images. The classification accuracy was promoted after the consideration of tillage time. To screen out sites with a reduction of maximum potential water retention, the land cover and soil map are overlaid to calculate the curve number. The optimal construction sites for depression storage are prioritized by the area of watersheds and volume of depression storage. The related authorities can use our results to create multipurpose ponds for sedimentation and flood detention, tourist attraction and recreation, microclimate adjustment, firefighting, irrigation and groundwater recharge.
大度台地因地形平緩且鄰近都會區，近年來因開發迅速不透水鋪面增加而降低入滲；此外， 旱季因週期性野火，易使林地變為草地，更降低水源涵養能力，如何快速監測地覆變遷，及有 效篩選水源涵養熱點區位，對水患管理極為重要。本研究藉由兩期之四季衛星影像，萃取常態 化差異植生指標 (Normalized Difference Vegetation Index, NDVI) 分類大度台地之地覆類別，然 草地與農地難以精確分類，遂此，透過加入農地耕作時間點，可有效提升草地及農地之精確度。 套疊地覆類別及土壤資料換算曲線值(Curve Number, CN)篩選最大蓄水潛勢下降之重點集水分 區，依集水面積與蓄洪體積優選窪蓄區位，研究成果可作為相關單位沉砂滯洪、灌溉、消防、 景觀遊憩、為氣候調節及地下水補注等多功能蓄水池之營造對策研擬。
|Appears in Collections:||第49卷 第01期|
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