Exploring effective best management practices in the Miyun reservoir watershed, China
Exploring effective best management practices in the Miyun reservoir watershed, China
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DOI：
10.1016/j.ecoleng.2018.08.020
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发表时间：
2018-11
影响因子：
3.8
通讯作者：
Jiali Qiu;Zhenyao Shen;Maoyi Huang;Xuesong Zhang
中科院分区：
文献类型：
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作者：
Jiali Qiu;Zhenyao Shen;Maoyi Huang;Xuesong Zhang
密云水库流域是拥有2175万人口的中国首都北京的主要饮用水源。近年来，密云水库供应清洁饮用水的能力受到富营养化（或藻华）加剧的威胁，主要原因是上游流域废水排放和过度施肥。因此，迫切需要设计有效的最佳管理实践（BMP）来减少上游营养负荷并改善密云水库的水质。在本研究中，我们为密云水库流域（MRW）建立了流域模型（水土评估工具），并使用长期沉积物、氮（N）和磷（P）数据对其进行了校准和验证。此外，我们开发了基于马尔可夫链的多目标优化程序，以探索在经济成本和水质响应之间进行权衡的最佳 BMP。使用分水岭模型和多目标优化算法，我们探索了 BMP 在目前正在考虑的两种场景下的潜在有效性。情景 1 假设 BMP 实施的资金来自国家拨款，目标是高水质标准，而情景 2 假设资金由农民提供，目标水质达到饮用水标准。我们发现两种情景在 BMP 的类型和空间配置以及相关经济成本方面存在巨大差异，这凸显出需要协调不同利益相关者的担忧，以达成各方都同意的 BMP 计划。此外，我们发现，跨子流域协调和针对汛期而不是全年水质标准可以显着降低 BMP 实施的经济成本，而不会大幅降低水质。这里开发的流域规模优化方法有望成为探索经济成本、水质改善以及决策者和利益相关者在 BMP 设计中的关注点之间权衡的有效工具，从而为可持续流域规模水资源管理和生态系统维护提供信息。
Miyun reservoir watershed is a major source of drinking water for China’s capital, Beijing, which has a population of 21.75 million. Recently, the capacity of the Miyun reservoir to supply clean drinking water has been threatened by increasing eutrophication (or algae bloom), mainly due to the discharge of wastewater and excessive fertilization application in the upstream watershed. Therefore, there is an urgent need to design effective best management practices (BMPs) to reduce upstream nutrient load and improve water quality in the Miyun reservoir. In this study, we built a watershed model (the Soil and Water Assessment Tool) for the Miyun Reservoir Watershed (MRW) and calibrated and validated it using long-term sediment, nitrogen (N) and phosphorus (P) data. Furthermore, we developed a Markov Chain based multi-objective optimization program to explore optimal BMPs with tradeoffs between economic costs and water quality responses. Using the watershed model and multi-objective optimization algorithms, we explored the potential effectiveness of BMPs under two scenarios that are currently being considered. Scenario 1 assumes that funding for BMP implementation comes from national grants and targets high water quality standards, whereas scenario 2 assumes funding is provided by farmers and targets water quality that meet the drinking water standards. We found substantial discrepancies between the two scenarios with respect to the types and spatial configurations of BMPs and associated economic costs, highlighting the need to reconcile concerns from different stakeholders in order to arrive at a BMP plan that all parties will agree upon. In addition, we found that cross-subwatershed coordination and targeting flood season instead of year-round water quality standards could pronouncedly reduce the economic costs of BMP implementations without substantially degrading water quality. The watershed scale optimization method developed here holds promise to serve as an effective tool to explore tradeoffs between economic costs, water quality improvements, and decision makers’ and stakeholders’ concerns in BMP design, thereby informing sustainable watershed scale water resources management and ecosystem maintenance.