本文介紹以防災式土地使用為命題回應都市水災衝擊之省思。當代永續都市之論述應走出都市與自然的二元對立，且面對當代都市及自然條件的根本性變化，新的都市肌理驅動新空間規劃思維的挑戰。在生態都市與緊密都市之間面對複雜的水災課題時，重新思考疏導式空間規劃與防堵式空間規劃兩者螺旋交織的辯證。本文以臺南市為分析地區，探究都市水災的空間分佈特性及受災土地使用的類型。首先利用臺南環境條件基礎資料並運用 FLO-2D 模式模擬四種情境的水災淹水潛勢範圍進行不同情境水災潛勢與土地使用比較分析；其次透過空間分析探尋水災的空間分佈特性，再者進行都市水災環境風險的量測，進而劃出不同水災情境的土地使用環境風險範圍，最後，比較水災地區的土地使用環境風險強度，作為初探未來防災式土地使用規劃的基礎。

This paper introduces a disaster mitigation land use plan designed as a response to urban floods. Contemporary sustainable urban discussion should unleash the dualistic opposition of urbanity and nature, and confront their differences. The new urban context stimulates challenges in new thinking regarding spatial planning. Complex flood issues between ecological and compact cities make it necessary to discuss a dialectical perspective in spatial plans for channels and dykes. This study adopts Tainan City in Taiwan as a case study area and investigates the spatial distribution features of urban flood and vulnerable land use types. First, the FLO-2D model is used to simulate four urban flood situations to analyze flood tendency and land use under different scenarios. Second, spatial analysis is used to explore the spatial features of floods. Furthermore, environmental risks of urban flood are appraised to schematically represent environmental risk land use area under various flood scenarios. Finally, the preliminary future mitigation land use plan is grounded on analysis of the comparative intensity of environmental risk land use in urban flood areas.