雨水貯集於臺灣各縣市水稻灌溉與民生用水之經濟可行性與兼具減洪效用之評估;Evaluating the County-level Economic Feasibility and Flood Mitigation Benefits of Rainwater Harvesting for Paddy Irrigation and Domestic Water Use in Taiwan

NCUIR > College of Earth Sciences > Graduate Institute of Hydrological and Oceanic Sciences > Electronic Thesis & Dissertation > Item 987654321/97443

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/97443

Title:	雨水貯集於臺灣各縣市水稻灌溉與民生用水之經濟可行性與兼具減洪效用之評估;Evaluating the County-level Economic Feasibility and Flood Mitigation Benefits of Rainwater Harvesting for Paddy Irrigation and Domestic Water Use in Taiwan
Authors:	羅心琦;Lo, Hsin-Chi
Contributors:	水文與海洋科學研究所
Keywords:	雨水貯集系統;集水與需求情境;供水經濟可行性;減洪;氣候變遷調適;Rainwater Harvesting Systems;Collection and Demand Scenarios;Water-supply Economic Feasibility;Flood Mitigation;Climate Change Adaptation
Date:	2025-08-20
Issue Date:	2025-10-17 11:18:56 (UTC+8)
Publisher:	國立中央大學
Abstract:	近年來，臺灣受氣候變遷影響，極端氣象事件頻繁發生，其中乾旱造成的水資源短缺對農業尤其水稻灌溉構成嚴峻挑戰；而已有相當多應用說明雨水貯集系統具有提升水資源系統韌性並降低旱澇風險之功能。本研究旨在評估不同雨水貯集系統容量、集水與供水情境在臺灣各縣市水稻田區域之供水穩定性、經濟可行性與其兼具減洪效用三方面之整體效益，作為因應氣候變遷下缺水與淹水之策略。本研究採用「溢流後取水（Yield-After-Spillage, YAS）」模式，並以供水量、體積可靠度、滿足天數與時間可靠度四項指標，評估雨水貯集系統對農業灌溉與非期作期間民生用水之供水能力；同時結合未來氣候變遷情境（SSP2-4.5 與 SSP5-8.5）進行供水效益之推估，並以淨現值（Net Present Value, NPV）與投資回本期（Payback Period, PBP）分析經濟可行性。結果顯示，北部地區因全年降雨分布較均勻，於一期與二期稻作皆展現較高之供水可靠度；南部、中部與東部地區則於二期稻作期間供水效益較佳。於全年降雨皆用於民生之情境下，多數北部與東部地區即使僅配置10 m³之雨水桶，即可達到90%可靠度。未來降雨趨於極端化，將導致供給一期作之潛能下降，二期則可能提升；民生用水部分，未來純雨水桶情境供水都增加，而因降雨集中使多數屋頂集水情境產生溢流後供水量較基期減少，僅有少數北部縣市在600 m²配置較大雨水桶時供水量增加。經濟分析方面，於現況水價情境下，多數情境難以達成回本，當採用農業用水戶願付價格進行評估時，回本潛力提升。減洪方面，採用合理化公式模擬逕流量，以滯留體積比評估各重現期設計暴雨下系統滯洪能力。模擬結果顯示，多數縣市選擇適當容量後可完全滯留該集水面積下延時90分鐘之暴雨逕流，然而減洪所需容量與供水導向配置存在差距。本研究建議未來可強化制度誘因與區域化設計，以提升雨水貯集系統於農業水資源調適政策中的應用潛力與推廣成效。;In recent years, Taiwan has experienced increasingly frequent extreme weather events due to climate change, with droughts posing significant challenges to agricultural irrigation, especially for rice cropping. Rainwater harvesting (RWH) systems, as a nature-based solution (NbS), have gained attention for their potential to enhance water resilience and mitigate both drought and flood risks. This study evaluates the overall effectiveness of RWH systems across Taiwan’s rice paddy regions, focusing on water supply reliability, economic feasibility, and flood mitigation potential under future climate scenarios.The Yield-After-Spillage (YAS) model was applied, and four indicators—water supply, volume reliability, satisfaction in time, and time reliability—were used to assess the performance of RWH systems for both agricultural irrigation and domestic use during non-cropping seasons. Among domestic-use scenarios, only scenario 4, which assumes year-round rainfall usage, was selected for detailed analysis due to its consistent rainfall distribution. Various tank capacities, catchment sizes, and daily water demand rates were evaluated across counties under SSP2-4.5 and SSP5-8.5 climate pathways. Economic feasibility was assessed using Net Present Value (NPV) and Payback Period (PBP). Results show that northern Taiwan, benefiting from more evenly distributed rainfall, generally achieves higher supply reliability in both the first and second cropping , while central, southern, and eastern regions perform better during the second cropping. For domestic use under Scenario 4, most northern and eastern counties achieve over 90% volumetric reliability even with just a 10 m³. However, performance differences emerge between collection types: while pure RWH systems with small catchments tend to benefit from future, roof area catchments with larger areas often face overflow losses due to concentrated storms, resulting in reduced supply efficiency—especially with smaller tanks. Only a few northern counties showed improved supply under the 600 m² roof area catchment with larger tanks. Economic analysis reveals that under current water pricing, most systems are not financially viable; however, when using a willingness-to-pay for agricultural water, payback potential improves, especially in northern counties with stable rainfall and eastern counties with high irrigation demand. For flood mitigation, the Rational Method was used to estimate runoff, and detention effectiveness was assessed based on retention volume ratios under different return periods. Simulation results indicate that many counties can fully retain 90-minute design storm runoff with properly sized systems, though the capacity needed for flood control often exceeds that for water supply. In conclusion, rainfall amount alone does not guarantee effective water supply; system performance is governed by the timing, intensity, and spatial distribution of rainfall, as well as system capacity and demand matching. This study highlights the importance of integrating climate-adaptive design and region-specific strategies, suggesting that institutional incentives and spatial planning will be key to promoting RWH systems as viable tools in Taiwan’s agricultural water resource adaptation policies.
Appears in Collections:	[Graduate Institute of Hydrological and Oceanic Sciences] Electronic Thesis & Dissertation

Files in This Item:

File	Description	Size	Format
index.html		0Kb	HTML	24	View/Open

社群 sharing

Loading...