Peatland subsidence enhances cultivated lowland flood risk
Peatland subsidence enhances cultivated lowland flood risk
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泥炭地沉降增加了耕地低地洪水风险
DOI：
10.1016/j.still.2021.105078
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发表时间：
2021
影响因子：
6.5
通讯作者：
H. Marttila
中科院分区：
文献类型：
--
作者：
L. Ikkala;Anna;Olli Utriainen;B. Kløve;H. Marttila
全世界的泥炭地正受到土地密集使用和排水的威胁，这导致土壤沉降。这对农业产生了影响，特别是在低梯度耕作的泥炭为主的低地上，洪水风险很高。在这项研究中，我们结合了历史土壤高程数据和新的激光雷达数据，以改善对低地河流系统沉降及其后果的估计。结果显示，芬兰西海岸沿岸泥炭地在过去24-51年间沉降了202 - 349 mm，平均沉降率为5.15-9.47 mm y-1。有机土层的深度可以部分解释沉降速率（R2= 0.710，p > 0.05）。研究结果还表明，耕地受淹的增加主要是由于土壤沉降，而不是由于河流系统受淹次数的增加。在过去的24-51年里，由于河流附近的土壤沉降，每年被洪水淹没的面积增加了101- 194%。将结果推广到流域尺度表明，在两个研究集水区（Siikajoki河流域）之一中，耕地的年洪水区增加了45%。这些结果证明了利用历史数据研究土壤沉降的价值，并证实了由于密集的排水和沉降，有机低地耕作的洪水风险增加。在未来的土地利用计划中，应考虑新的管理策略，如泥炭地复湿、恢复和沼泽化，以减少沉降，为农民提供新的收入来源。
Peatlands worldwide are being threatened by intensive land use and drainage, which leads to soil subsidence. This has consequences for farming, especially on low-gradient cultivated peat-dominated lowlands with high flood risk. In this study, we combined historical soil elevation data and new lidar data to improve the estimation of subsidence and its consequences for lowland river systems. The results showed 202−349 mm subsidence within the last 24–51 years, with a mean rate of 5.15–9.47 mm y−1for riparian peatland on the west coast of Finland. The subsidence rate was partly explained by the depth of the organic soil layer (R2= 0.710, p > 0.05). The results also showed that increasing flooding of cultivated fields is mainly due to soil subsidence, not to increased flooding occurrence in river systems. The area flooded annually was found to increase by 101–194 % for the last 24–51 years, due to soil subsidence near rivers. Generalization of the results to catchment scale indicated an increase in the annual flood zone of 45 % in cultivated fields in one of two study catchments (Siikajoki river basin). These results demonstrate the value of using historical data to study soil subsidence and confirm that the risk of flooding increases in cultivated organic lowlands due to intensive drainage and subsidence. New management strategies, such as peatland rewetting, restoration, and paludiculture, should be considered in future land use plans to reduce subsidence and provide new income streams for farmers.