以遊戲模擬方法探討乾旱時期水市場機制對水資源再分配之可行性—以桃園地區為例

Investigating the Feasibility of Water Market in Water　Reallocation during Drought Periods by Simulation Gaming: A Case Study of Taoyuan, Taiwan

王尊麟(Zun-Lin Wang)

指導教授 ： 童慶斌

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201900536

摘要

氣候變遷可能使得台灣面臨乾季極端乾旱風險增加，更具彈性與調適能力的水資源管理方式成為政策決策者必須思考的關鍵議題。現行制度在乾旱時期水資源調度上，乃透過政府協調農業停灌休耕，農民對於耕作與否並無決定權，「農水工用」情形在水資源調配上存在公平性爭議。在此背景下，水市場或可成為水資源再分配的調適選項，政府無需強制介入，透過市場交易機制消弭灌溉用水移用爭議，同時提高水資源運用效率，反映不同時間點水的價值差異。
　　遊戲模擬(simulation gaming)方法有助於政策決策者評估一項假設性政策的可行性，並了解利害關係人間的互動關係。本研究以桃園地區為例，分別建構石門水庫供水系統動力模式與水稻田水平衡模式，將兩者整合於一套水市場模擬遊戲(water market simulation game, WMSG)中，使遊戲模擬結果能貼近真實水資源分配情況，並招募受試者參與遊戲交易決策。
　　研究結果顯示，石門水庫供水系統動力模式經合理性驗證，能應用於模擬桃園地區水資源分配情況。應用水稻田水平衡模式推估而得之修正後農業計畫配水量，在總量上與現行實務之推估結果接近，但更能反映稻作不同生育階段之灌溉需水量差異，依旬別不同而有峰谷波動。遊戲模擬結果顯示，水市場機制讓工業方面臨乾旱缺水時必須支付農業方更高的購水費用，農業方保有耕種與否之決定權。水庫有效蓄水量相比無交易情境而言有所增加，唯其增額不多。主要影響水庫空庫與否之因子在於農業計畫配水量之多寡，因此如何訂定合適的農業計畫配水量成為政策決策者必須優先思考的問題。遊戲模擬過程中，除了資訊的公開性外，資訊的「易解讀性」對於玩家決策判斷影響甚大。本研究為探討水市場機制之可行性提出實際模擬方法及工具，但仍存在許多改善空間，後續研究建議進一步探討不同情境下玩家交易策略及水資源再分配結果，強化遊戲模擬與政策實務應用之連結。

關鍵字

水市場 ； 遊戲模擬 ； 系統動力模式 ； 水資源再分配

並列摘要

Under the impact of climate change, the frequency of extreme precipitation and drought events has been increasing. Flexible water resources management should be considered by policy makers to increase adaptive capacity. In Taiwan, the government usually guides agricultural fallows to transfer water to meet the needs of domestic and industrial water demands during droughts. However, this situation causes that the cultivation rights of farmers are not guaranteed even though the priority of agricultural water demand is higher than that of industry by law.
　　Water market mechanism may be potential to solve this fairness dispute of water reallocation. To assess the feasibility of water market as an adaptation method of water reallocation, simulation gaming is an appropriate approach. It can help policy makers assess a hypothetical policy scenario and figure out the relationship and interaction between stakeholders. In this study, Taoyuan region is chosen as the study area and a water market simulation game (WMSG) is developed. WMSG integrates water supply system dynamics model and paddy field water balance model to reflect the water resource transmission and the hydrological mechanisms of the real world. The subjects are invited to play the game as an agricultural or industrial stakeholder and carry on the round-designed water trading.
　　Results show that Shimen Reservoir water supply system dynamics model can be applied to estimate the variation of reservoir water level under different hydrological scenarios. The rational agricultural planned allocation is calculated via paddy field water balance model. Total amount of the modified agricultural planned allocation is close to the practical method but more reasonably present the characteristics of irrigation water demand at different growing stages. The settlement of WMSG indicates that industrial players are willing to pay more costs on water purchase to prevent severe loss of production line shutdown caused by water shortage. Agricultural players have the right to decide whether to sell water or to keep farming. The amount of effective storage of Shimen reservoir has slightly increased when compared to the non-trading scenario. The key factor that determines whether the reservoir will be empty or not is the amount of agricultural planned allocation. The author argues that how to formulate a rational agricultural planned allocation is the most important issue for policy makers while considering water reallocation adaptation in Taiwan. Besides transparency and accessibility, interpretability of market information affects player’s decision-making significantly. This study provides practical application tools and models to assess the feasibility of water market mechanism despite still having room to improve. Further research is needed. To enhance the link between simulation game and policy applications, more games should be conducted to discuss the transaction strategies of players and the benefits of water reallocation under different simulation scenarios.

並列關鍵字

water market ； simulation gaming ； system dynamic model ； water reallocation

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