Saha Tamal Kanti, Pal Swades, Sarda Rajesh
Department of Geography, University of Gour Banga, Malda, West Bengal, 732103, India.
Environ Sci Pollut Res Int. 2022 Oct;29(50):75769-75789. doi: 10.1007/s11356-022-21072-6. Epub 2022 Jun 3.
A good number of researchers investigated the impact of flow modification on hydrological, ecological, and geomorphological conditions in a river. A few works also focused on hydrological modification on wetland with some parameters but as far the knowledge is concerned, linking river flow modification to wetland hydrological and morphological transformation following an integrated modeling approach is often lacking. The current study aimed to explore the degree of hydrological alteration in the river and its effect on downstream riparian wetlands by adopting advanced modeling approaches. After damming, maximally 67 to 95% hydrological alteration was recorded for maximum, minimum, and average discharges. Wavelet transformation analysis figured out a strong power spectrum after 2012 (damming year). Due to attenuation of flow, the active inundation area was reduced by 66.2%. After damming, 524.03 km (48.9% of total pre-dam wetland) was completely obliterated. Hydrological strength (HS) modeling also reported areas under high HS declined by 14% after post-dam condition. Wetland hydrological security state (WSS) and HS matrix, a new approach, are used to explore wetland characteristics of inundation connectivity and hydrological security state. WSS was defined based on lateral hydrological connectivity. HS under critical and stress WWS zones deteriorated in the post-dam period. The morphological transformation was also well recognized showing an increase in area under the patch, edge, and a decrease in the area under the large core area. All these findings established a clear linkage between river flow modification and wetland transformation, and they provided a good clue for managing wetlands.
许多研究人员调查了水流改变对河流的水文、生态和地貌条件的影响。也有一些研究关注了湿地的水文改变及一些参数，但就目前的认知而言，采用综合建模方法将河流流量改变与湿地水文和形态转变联系起来的研究还很缺乏。本研究旨在通过采用先进的建模方法，探讨河流的水文变化程度及其对下游河岸湿地的影响。筑坝后，最大、最小和平均流量的水文变化记录最高达到67%至95%。小波变换分析表明，2012年（筑坝年份）之后出现了很强的功率谱。由于水流衰减，活跃淹没面积减少了66.2%。筑坝后，524.03公里（占大坝建成前湿地总面积的48.9%）完全消失。水文强度（HS）建模还报告称，大坝建成后，高HS区域面积下降了14%。湿地水文安全状态（WSS）和HS矩阵这一新方法，被用于探究湿地淹没连通性和水文安全状态的特征。WSS是基于侧向水文连通性定义的。在大坝建成后的时期，关键和压力WWS区域的HS恶化。形态转变也很明显，斑块和边缘区域面积增加，大核心区域面积减少。所有这些发现都明确了河流流量改变与湿地转变之间的联系，并为湿地管理提供了很好的线索。
