Lake Malawi's threshold behaviour: A stakeholder-informed model to simulate sensitivity to climate change
Lake Malawi's threshold behaviour: A stakeholder-informed model to simulate sensitivity to climate change
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DOI：
10.1016/j.jhydrol.2020.124671
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发表时间：
2020-05-01
影响因子：
6.4
通讯作者：
Mkwambisi, David
中科院分区：
文献类型：
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作者：
Bhave, Ajay G.;Bulcock, Lauren;Mkwambisi, David
马拉维90%以上的发电和灌溉依赖马拉维湖流入希雷河的水流。最近的湖水位下降引发了人们对未来气候变化影响的担忧，包括如果超过马拉维湖流出阈值（LMOT）则没有流出的风险。为了满足模型联合制作的需求，我们不断地让利益相关者参与数据收集，并获取当地系统的见解和管理优先事项，为马拉维湖郡河流域的水评估和规划 (WEAP) 模型的开发提供信息。我们使用简单的模型设置和手动校准来实现数据稀疏性和历史管理决策的有限记录。该模型令人满意地捕获了 1960-2009 年期间马拉维湖支流有限的观测到的水流模式和湖泊水位变化，但是，湖泊水位模拟中的小误差会严重影响每月流出量的模拟。沿岸国家马拉维、坦桑尼亚和莫桑比克分别贡献了约 55%、41% 和 4% 的湖泊流入量（1960-2009 年平均值）。 WEAP 模型采用 29 个经过偏差校正的全球气候模型预测（2021-2050 年）并假设关键基础设施的当前运行规则没有变化，模拟了广泛的变化。其中包括会导致下游洪水的高得多的湖泊水位，以及低得多的湖泊水位，其中有 11 个预测低于 LMOT。这两种结果都将对下游水电和灌溉产生重大影响。未来的水资源管理计划需要确定和评估能够解决湖泊水位多年变化以及未来气候和水文模型输出固有的不确定性的战略。
Over 90% of Malawi's electricity generation and irrigation depend on Lake Malawi outflows into the Shire River. Recent lake level declines have raised concerns over future climate change impacts, including the risk of no outflows if the Lake Malawi Outflow Threshold (LMOT) is passed. Addressing calls for model co-production, we iteratively engage stakeholders in data collection, and eliciting local system insights and management priorities, to inform the development of a Water Evaluation And Planning (WEAP) model for the Lake Malawi Shire River Basin. We use a simple model setup and manual calibration to allow for data sparsity and limited documentation of historical management decisions. The model satisfactorily captures limited observed streamflow patterns of Lake Malawi tributaries and lake level variations for the period 1960-2009, however, small errors in lake level simulation significantly affect simulation of monthly outflows. The riparian countries, Malawi, Tanzania and Mozambique contribute approximately 55%, 41% and 4% respectively to lake inflows (1960-2009 average). Forced with 29 bias-corrected global climate model projections (2021-2050) and assuming no change in current operating rules of key infrastructure, the WEAP model simulates wide-ranging changes. These include much higher lake levels that would cause downstream floods, and much lower lake levels, including 11 projections that fall below the LMOT. Both outcomes would have major implications for downstream hydropower and irrigation. Future water management plans require identification and evaluation of strategies that can address multi-year shifts in lake levels and the uncertainty inherent in future climate and hydrological model outputs.