Hydrologic impacts of engineering projects on the Tigris–Euphrates system and its marshlands
Hydrologic impacts of engineering projects on the Tigris–Euphrates system and its marshlands
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DOI：
10.1016/j.jhydrol.2008.01.029
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发表时间：
2008-05
影响因子：
6.4
通讯作者：
C. Jones;M. Sultan;E. Yan;A. Milewski;M. Hussein;A. Al-Dousari;S. Al-Kaisy;R. Becker
中科院分区：
文献类型：
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作者：
C. Jones;M. Sultan;E. Yan;A. Milewski;M. Hussein;A. Al-Dousari;S. Al-Kaisy;R. Becker
对淡水供应的需求不断增长，导致水管理实践正在改变世界范围内的自然流动系统。这些自然系统中破坏最严重的是底格里斯河-幼发拉底河流域，在过去的三十年里，该流域见证了60多个工程项目的建设，这些工程项目消除了季节性洪水，减少了自然流量，并大大减少了美索不达米亚沼泽下游的面积（1966年：8000平方公里; 2002年：750平方公里）。我们构建了一个基于流域的连续（1964-1998年）降雨径流模型的流域（面积：106 km 2）使用土壤水分评估工具（SWAT）模型来了解自然流系统的动态，并调查减少的总流量和相关的土地覆盖和土地利用变化的影响下游的沼泽。该模型进行了校准（1964年至1970年）和验证（1971年至1998年）对流流量计数据。使用校准的模型，我们计算了在整个建模期间，底格里斯河和幼发拉底河流入巴士拉市附近（31°N，47.5°E）沼泽的平均月流量（AMFR），平均月峰值流量（AMPFR）和年流量（AFV）的时间变化。模型结果表明，（6301 m3/s）和多年平均流量（AAFV：80× 109 m3/yr），A期（10/1/1965-09/30/1973），在大坝建设之前，在B1期逐渐减少（10/1/1973-09/30/1989; AMPFR：3073m3/s; AAFV：55×109m3/yr）和B2（10/1/1989-09/30/1998; AMPFR，2319 m3/s; AAFV：50× 109 m3/yr），见证了大坝的建设（B1：Keban、Tabqa、Hamrin、Haditha、摩苏尔、Karakaya; B2：Ataturk），这是由于填充人工湖、蓄水蒸发和渗透以及将其用于灌溉的综合影响。为了研究减少流量对沼泽面积范围的影响，我们研究了从时间卫星数据中提取的沼泽大小的变化（1966年、1975年、1976年、1977年、1984年、1985年、1986年、1987年）在大约相同的时间段获得（七月至九月）与本地主要工程项目（例如，战役河的王冠，对领袖的忠诚运河，战役河的母亲）。结果表明，中央和哈马尔沼泽的面积范围（例如，1966年：7970 km 2，1977年：6680 km 2，1984年：5270 km 2）随着AFV的减少而减少（例如，1966年：60.8× 109 m3，1977年：56.9× 109 m3，1984年：37.6× 109 m3）。使用一个关系，描述减少AFV的沼泽面积范围的影响，我们评估了流量的额外减少，将导致在未来几年内实施计划中的工程项目对底格里斯河-幼发拉底河系统的影响。正在进行的安纳托利亚东南部项目完成后，预计AFV的减少量超过5× 109 m3/年，中部和Al-Hammar地区的可持续沼泽将至少再减少550平方公里。
Rising demands for fresh water supplies are leading to water management practices that are altering natural flow systems world-wide. One of the most devastated of these natural systems is the Tigris–Euphrates watershed that over the past three decades has witnessed the construction of over 60 engineering projects that eliminated seasonal flooding, reduced natural flow and dramatically reduced the areal extent (1966: 8000km2; 2002: 750km2) of the Mesopotamian Marshes downstream. We constructed a catchment-based continuous (1964–1998) rainfall runoff model for the watershed (area: 106km2) using the Soil Water Assessment Tool (SWAT) model to understand the dynamics of the natural flow system, and to investigate the impacts of reduced overall flow and the related land cover and landuse change downstream in the marshes. The model was calibrated (1964–1970) and validated (1971–1998) against stream flow gauge data. Using the calibrated model we calculated the temporal variations in the average monthly flow rate (AMFR), the average monthly peak flow rate (AMPFR), and annual flow volume (AFV) of the Tigris and Euphrates into the marshes at a location near Al-Basrah city (31°N, 47.5°E) throughout the modeled period. Model results indicate that the AMPFR (6301m3/s) and average annual flow volume (AAFV: 80×109m3/yr) for period A (10/1/1965–09/30/1973), preceding the construction of the major dams is progressively diminished in periods B1 (10/1/1973–09/30/1989; AMPFR: 3073m3/s; AAFV: 55×109m3/yr) and B2 (10/1/1989–09/30/1998; AMPFR, 2319m3/s; AAFV: 50×109m3/yr) that witnessed the construction of the major dams (B1: Keban, Tabqa, Hamrin, Haditha, Mosul, Karakaya; B2: Ataturk) due to the combined effects of filling artificial lakes, evaporation and infiltration of impounded water and its utilization for irrigation purposes. To investigate the impacts of reduced flow on the areal extent of the marshes, we examined the variation in marsh size extracted from temporal satellite data (1966, 1975, 1976, 1977, 1984, 1985, 1986, 1987) acquired around the same approximate time period (July to September) of the year versus simulated AFV for the period preceding the onset (1987) of major local engineering projects (e.g., Crown of Battles River, Loyalty to the Leader Canal, Mother of Battles River) in and around the investigated marshes. Results indicate that the areal extent of the Central and Al-Hammar marshes (e.g., 1966: 7970km2, 1977: 6680km2, 1984: 5270km2) decreases with a decrease in AFV (e.g., 1966: 60.8×109m3, 1977: 56.9×109m3, 1984: 37.6×109m3). Using a relationship that describes the impact of reduced AFV on the areal extent of the marshes, we evaluated the impact of additional reductions in flow that will result from the implementation of the planned engineering projects on the Tigris–Euphrates system over the next few years. Upon completion of the ongoing South Eastern Anatolia project, with projected reductions in AFV exceeding 5×109m3/yr, the sustainable marshes in the Central and Al-Hammar area will be reduced by at least an additional 550km2.