Characterizing the severity and risk of drought in the Poudre River, Colorado
Characterizing the severity and risk of drought in the Poudre River, Colorado
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DOI：
10.1061/(asce)0733-9496(2005)131:5(383
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发表时间：
2005-09-01
期刊：
影响因子：
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通讯作者：
Vincent, E
中科院分区：
文献类型：
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作者：
Salas, JD;Fu, CJ;Vincent, E
在某一地区实施用水限制与不断演变的干旱的严重程度密切相关；因此，像城市水务局这样的水管理机构经常面临一个特定干旱事件有多严重或多严重的问题。虽然这个问题通常是用干旱指数（例如，帕尔默干旱严重程度指数）来检查的，但不幸的是，它们没有提供任何关于干旱频率或复发时间的信息，也没有提供任何关于特定干旱事件在给定时间范围内可能发生的风险的信息。在本文中，替代干旱事件的严重程度与确定洪水严重程度的概念类似，即确定洪水事件的重现期，例如500年一遇的洪水。我们开发了基于历史数据、生成数据和数学算法确定干旱严重程度的程序。我们特别关注发生在美国西部的干旱，并以科罗拉多州的波德雷河为例。该分析是基于119年的波德雷河归化流量记录。采用随机模型生成长期综合流量，并据此确定干旱事件的重现期和风险。此外，我们还使用数学算法来确定干旱事件的分布及其回归期。以样本均值作为需水量阈值，得到干旱严重程度、干旱频次和干旱风险统计；例如，3年（2000-2002年）干旱的严重程度（即3年干旱，面积为404,011英亩-英尺）为1000年的回复期，这种3年干旱在25年期间发生的风险约为2.4%。
The implementation of water use restrictions in a given district is very much related to the severity of an evolving drought; thus, water management agencies such as City Water Departments often face the question of how critical or severe a particular drought event is. While this question has typically been examined using drought indices (e.g., the Palmer Drought Severity Index), unfortunately they do not provide any information on the frequency or recurrence time of the drought or on the risk that specific drought events may occur in a given time horizon. In this paper, the severity of alternative drought events are determined following a similar concept as for the severity of floods, i.e., the return period of a flood event, e.g., the 500-year flood. We develop procedures for determining drought severity based on historical data, generated data, and mathematical algorithms. In particular, we focus on the drought that has been occurring in the Western United States and take the Poudre River, Colo., as an example. The analysis was based on 119 years of records of naturalized flows of the Poudre River. A stochastic model was used for generating long-term synthetic flows, from which the return period and risk of drought events were determined. In addition, we used a mathematical algorithm for determining the distribution of drought events and their return periods. Assuming the sample mean as the water demand threshold, drought severity, frequency, and risk statistics were obtained; e.g., the severity of the 3-year (2000-2002) drought (i.e., 3-year drought with D > 404,011 acre-ft) is of the order of a 1,000-year return period and the risk that such a 3-year drought will occur in a 25-year period is about 2.4%.