Understand Ephemeral Gully Mechanics and Develop Large Scale Decision Support Systems for Improved Watershed Management

非点源污染，特别是来自农田的沉积物和磷径流，正在严重损害世界各地的一些水体。近十年来，五大湖之一的伊利湖由于有害污染物特别是沉积物结合磷含量的增加而受到严重威胁。2011年，伊利湖的磷诱导藻类水华非常高，2015年夏天产生了100年来最大的藻类水华。随着人类活动对气候和土地利用的持续变化，预计这种退化将进一步恶化。 减少泥沙和磷径流的研究更多地集中在了解片和细沟侵蚀过程，开发模拟这些过程的水文和水质（HWQ）模型，并使用模型来调查政策相关问题。只是在最近的十年里，短暂的沟（EGs）被确定为一个主要的来源，研究表明，他们的贡献超过片和细沟侵蚀。EGs是土壤侵蚀的局部区域，充当将细沉积物和磷从高地农田转移到溪流通道的小通道。在过去的几年中，正在努力研究EGs从耕作操作（初夏），并被列为子程序在几个HWQ模型。这些子程序只能模拟EG侵蚀，不能模拟磷素径流。此外，在北方纬度（加拿大），EGs的形式不仅在初夏（耕作后），但也在晚春作为融雪过程的结果。 我的研究计划，在未来五年内，将推进EG动力学（例如形成，形态）和运输机制（例如沉积物和磷径流）背后的科学的理解。此外，一种新的模式，能够识别EGs，也估计泥沙和磷径流在所有气候/季节条件下，不同的空间和时间尺度将开发。开发的模型将耦合到广泛使用的土壤和水评估工具（SWAT）和一个综合的基于网络的决策支持系统（IWBDSS）将被开发。IWBDSS将应用于对伊利湖有贡献的流域，以支持各种流域规划、经济和政策分析，并最终帮助安大略省政府实现到2025年将进入伊利湖的磷减少40%的愿景。所开发的模型和决策支持系统也可以应用于加拿大或世界上的任何流域，以做出更好的流域综合管理决策。最重要的是，我的研究计划将产生下一代工程师/研究人员精通现场实验和HWQ模型的使用/开发，并能够为不断变化的土地利用和气候下的新兴和未来水量和水质问题提供工程解决方案。

Non-point source pollution especially sediment and phosphorus runoff from agricultural fields are severely impairing several water bodies across the world. In the recent decade, Lake Erie (one of the Great Lakes) is under serious threat due to increased levels of harmful pollutants especially sediment-bound phosphorus. In 2011, the phosphorus-induced algae blooms in Lake Erie were exceedingly high and the summer of 2015 produced the largest algae bloom in 100 years. This degradation is projected to worsen with continued anthropogenic climate and landuse change. The research towards reducing the sediment and phosphorus runoff is focused more towards understanding sheet and rill erosion processes, develop Hydrologic and Water Quality (HWQ) models that simulate these processes and use models to investigate policy relevant issues. Only in the recent decade, Ephemeral Gullies (EGs) are identified as a major source and studies have shown that they contribute more than sheet and rill erosion. EGs are localized areas of soil erosion that act as small channels that transfer fine sediment and phosphorus from upland agricultural fields to stream channels. In the last few years, efforts are being made to study EGs resulting from tillage operations (early summer) and are being included as sub-routines in few HWQ models. These developed sub-routines can only simulate EG erosion but not phosphorus runoff. Furthermore, in northern latitudes (Canada), the EGs form not only during early summer (after tillage) but also during late spring as a result of snowmelt processes. My research program, in the next five years, will advance the understanding of the science behind EG dynamics (e.g. formation, morphology) and the transport mechanisms (e.g. sediment and phosphorus runoff). Furthermore, a novel model capable of identifying EGs and also estimating sediment and phosphorus runoff in all climatic/seasonal conditions under different spatial and temporal scales will be developed. The developed model will be coupled into widely used Soil and Water Assessment Tool (SWAT) and an integrated web-based decision support system (IWBDSS) will be developed. IWBDSS will be applied in watersheds contributing to Lake Erie to support a wide variety of watershed planning, economic and policy analysis and ultimately help Ontario's government vision to reduce 40% phosphorus entering Lake Erie by 2025. The models and decision support systems developed can also be applied in any watershed across Canada or in the world to make better integrated watershed management decisions. Most importantly, my research program will produce next generation engineers/researchers proficient in both field experimentation and usage/development of HWQ models and capable of providing engineered solutions to emerging and future water quantity and quality issues under changing landuse and climate.