Collaborative Research: RAPID: Short-and Long-term Sediment Dynamics Following Wildfire in Chaparral Environments

这个RAPID项目的重点是生产和交付干砂，这是美国西部陡坡火灾后的一种特征和即时反应。干沉降产生于旱季的运输过程，在此过程中，砾石沉积物在重力作用下沿山坡向下移动，被植被截住。这种物质为灌木林环境中野火后的河道提供了重要的沉积物来源。调查人员将量化2013年5月南加州大火烧毁大梧树峡谷后沿河道边缘沉积的干散失沉积物的体积。雨季前后（通常在10月1日左右开始）的地面激光扫描将捕捉到景观地形的初始变化。这些数据将通过实地调查得到补充。在火灾后的第一年收集的数据对于发展干漂移动力学模型是重要的。调查人员拥有大梧树峡谷和附近两个具有不同火灾历史的类似盆地的地貌数据，跨度超过25年，其中一条支流通往北分叉的Matilija Creek，在1985年7月的惠勒大火中完全烧毁，另一条支流通往马里布溪，至今未被烧毁。比较这三个地点的干沉降过程，可以直接比较林荫环境中野火后的短期和长期沉积物动态。发展对野火短期和长期影响的预测性理解至关重要，特别是在气候变化的时代，野火的频率和规模都在增加。然而，准确预测火灾后的影响仍然是难以捉摸的，基于物理的火灾后径流和侵蚀模型仍在开发中。拟议中的项目将整合研究和教育，涉及来自加州州立大学海峡群岛分校（CSUCI）的本科生。这些学生将在协助pi进行现场数据收集和分析的同时完成他们的本科课程。其中两名学生是CSUCI校区西班牙裔服务机构ACCESO（通过STEM机会实现合作大学教育）研究助理项目的参与者。这些学生将获得宝贵的研究经验，包括使用尖端技术的培训。

This RAPID project focuses on production and delivery of dry ravel, a characteristic and immediate post-fire response on steep slopes in the western USA. Dry ravel arises from a dry-season transport process whereby gravel sediment moving down hillslopes by gravity becomes trapped by vegetation. This material provides a significant sediment source into river channels after wildfire in chaparral environments. The investigators will quantify the volume of dry ravel sediment deposited along channel margins as a result of the Springs Fire that burned Big Sycamore Canyon in southern California during May 2013. Terrestrial laser scanning before and after the rainy season (which typically begins around October 1) will capture initial changes in landscape topography. These data will be augmented by field surveys. Data collected during the first post-fire year are important for developing models of the dynamics of dry ravel. The investigators have geomorphic data spanning over 25 years for Big Sycamore Canyon and two comparable basins nearby with different fire histories--a tributary to north fork Matilija Creek that burned completely during the July 1985 Wheeler Fire-- and a tributary to Malibu Creek that has remained unburned. Comparing dry ravel processes at these three sites will enable a direct comparison of both short- and long-term sediment dynamics following wildfire in chaparral environments. Developing a predictive understanding of both short- and long-term effects of wildfire is critical, especially in an era of changing climate that has increased frequencies and magnitudes of wildfires. Yet, accurately predicting post-fire effects remains elusive, and physically-based models of post-fire runoff and erosion are still being developed. The proposed project will integrate research and education by involving undergraduate students from California State University, Channel Islands (CSUCI). These students will pursue their capstone undergraduate coursework while assisting the PIs with field data collection and analysis. Two of these students are participants of the Hispanic-Serving Institutes ACCESO (Achieving a Cooperative College Education Through STEM Opportunities) Research Assistant Program on the CSUCI campus. These students will receive valuable research experiences including training in use of cutting-edge technologies.