Geology Department, State University of New York College at Cortland, Cortland, NY 13045, USA.
School of Geography and the Environment, University of Oxford, Oxford, United Kingdom.
Sci Total Environ. 2018 Oct 1;637-638:907-917. doi: 10.1016/j.scitotenv.2018.04.349. Epub 2018 May 12.
Delta systems formed by the deposition of sediments at the mouths of large catchments are vulnerable to sea level rise and other climate change impacts. Deltas often have some of the highest population densities in the world and the Mahanadi Delta in India is one of these, with a population of 39 million. The Mahanadi River is a major river in East Central India and flows through Chattisgarh and Orissa states before discharging into the Bay of Bengal. This study uses an Integrated Catchment Model (INCA) to simulate flow dynamics and water quality (nitrogen and phosphorus) and to analyze the impacts of climate change and socio-economic drivers in the Mahanadi River system. Future flows affected by large population growth, effluent discharge increases and changes in irrigation water demand from changing land uses are assessed under shared socio-economic pathways (SSPs). Model results indicate a significant increase in monsoon flows under the future climates at 2050s (2041-2060) and 2090s (2079-2098) which greatly enhances flood potential. The water availability under low flow conditions will be worsened because of increased water demand from population growth and increased irrigation in the future. Decreased concentrations of nitrogen and phosphorus are expected due to increased flow hence dilution. Socio-economic scenarios have a significant impact on water quality but less impact on the river flow. For example, higher population growth, increased sewage treatment discharges, land use change and enhanced atmospheric deposition would result in the deterioration of water quality, while the upgrade of the sewage treatment works lead to improved water quality. In summary, socio-economic scenarios would change future water quality of the Mahanadi River and alter nutrient fluxes transported into the delta region. This study has serious implications for people's livelihoods in the deltaic area and could impact coastal and Bay of Bengal water ecology.
由大型流域河口沉积物沉积形成的三角洲系统容易受到海平面上升和其他气候变化的影响。三角洲通常是世界上人口密度最高的地区之一，印度的马哈纳迪三角洲就是其中之一，拥有 3900 万人口。马哈纳迪河是印度中东部的一条主要河流，流经恰蒂斯加尔邦和奥里萨邦，然后流入孟加拉湾。本研究使用综合流域模型（INCA）模拟水流动力学和水质（氮和磷），并分析气候变化和社会经济驱动因素对马哈纳迪河流系统的影响。在共享社会经济途径（SSP）下，评估未来受人口增长、污水排放量增加以及土地利用变化引起的灌溉用水需求变化影响的未来流量。模型结果表明，未来气候在 2050 年代（2041-2060 年）和 2090 年代（2079-2098 年）的季风流量显著增加，这大大增加了洪水的可能性。由于未来人口增长和灌溉增加导致的用水量增加，低流量条件下的水资源供应将恶化。由于流量增加导致的稀释，预计氮和磷的浓度会降低。社会经济情景对水质有重大影响，但对河流流量的影响较小。例如，人口增长、污水排放量增加、土地利用变化和大气沉降增加会导致水质恶化，而污水处理厂的升级则会改善水质。总之，社会经济情景将改变马哈纳迪河的未来水质，并改变输送到三角洲地区的营养物质通量。本研究对三角洲地区人民的生计具有重要意义，并可能影响沿海和孟加拉湾的水生态。
