| 摘要: |
| 修建海岸水库是满足滨海地区淡水资源的保障的一个重要方式，为了进一步分析海岸水库的建立对滨海含水层的海水入侵的影响，采用SUTRA（saturated-unsaturated transport）模型建立具有代表性的二维海岸模型开展定量和定性研究，结果表明：潮汐作用抑制底层盐水楔的入侵，加快海陆物质交换；实例中计算表明建坝后，海岸水库坝体的建立加剧了海水入侵；水库水位在平均海平面以下时，潮汐动力因素占主导，海水入侵严重且随着水位抬高，海水入侵程度基本保持不变，应注意海水入侵的防治；库区水位在平均海平面以上时，海水入侵程度随着库区水位的抬高而减少，可以调节水库水位进行滨海含水层的海水入侵的防控；海岸水库在建设中存在一个控制水位，当水库水位在控制水位以上，库区水体盐度和含水层淡水储量能得到保证；库区高水位时内陆物质运移时间较长，运移区域较广，氮类污染物易在库底含水层堆积，需重视含水层的地下水污染防治。 |
| 关键词: 海水入侵 盐水楔 海岸水库 物质输运 |
| DOI：10.11759/hykx20201013002 |
| 分类号:P731.2 |
| 基金项目:国家重点研发项目（2019YFC0409004） |
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| Numerical study of the influence of coastal reservoir on seawater intrusion |
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JI Zhi-ling, ZHOU Chen-qi, ZHAO Zhong-wei, KONG Jun
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State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
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| Abstract: |
| The construction of coastal reservoirs is one of alternative methods which plays an important role in guaranteeing freshwater resource supply in coastal areas. To analyze the impact of coastal reservoirs on the seawater intrusion in coastal aquifers, a SUTRA (saturated-unsaturated transport) model was adopted to establish a representative two-dimensional coastal case for the study. Quantitative and qualitative research has been carried out based on various scenarios. Results reveal that the tidal action can inhibit the intrusion of the bottom saltwater wedge and accelerate the exchange between the subsurface and surface water before the construction of the coastal reservoir. After the establishment of the coastal reservoir, such features can be changed corresponding to different reservoir water levels. When the reservoir water level is below the mean sea level, tidal dynamic factors play a dominant role and lead to a more serious seawater intrusion. Such trends remain unchanged when the water level further rises. Much attention should be given to the prevention and control of seawater intrusion under this condition. Moreover, when the water level of the reservoir area is above the mean sea level, the degree of seawater intrusion decreases with the elevation of the water level in the reservoir. A series of numerical results have confirmed that there is a critical water level above which the water level of the reservoir can effectively ensure the water quality and freshwater resource supply in the reservoir. Further study has also shown that when the water level in the reservoir area is high, the inland material transport time is lengthened, the transport area is widened, and the nitrogen pollutants are easy to accumulate in the reservoir's bottom aquifer. Such potential risks deserve much attention in designing a coastal reservoir. |
| Key words: seawater intrusion saline wedge coastal reservoir mass transport |
