Bedload sediment transport and morphologic data in an unrestored and restored reach of Wilket Creek, Toronto, Canada.

This project monitors the movement of coarse sediment and morphological change through a newly restored section of Wilket Creek (Toronto), and directly compares bedload transport processes with an adjacent un-restored section. This study presents a means of monitoring bedload transport processes in restored rivers, and results can inform future river restoration designs. Data was collected from an un-restored reach and a restored reach of Wilket Creek, Toronto, Canada. The grain size distribution of the restored reach was done using a Wolman Pebble count with a 200-stone sample size. Bedload transport was monitored over three years using Radio Frequency Identification (RFID) tracer stones. Two waves of tracers were seeded. The first wave was seeded in August, 2013, and comprised of 143 tracers in the unrestored reach and 299 tracers in the restored reach in 5 size classes. The second tracer wave was seeded in August, 2015 and comprised of 300 tracers seeded in the restored reach in 3 size classes. Tracer positions were recorded after each major rainfall event during the active field season each year, resulting in a total of 10 recoveries of the first tracer wave, and 12 recoveries of the second tracer wave. With each recovery, the travel distance of each tracer since its last known position is calculated. Repeat cross section surveys were conducted through the restored reach to monitor morphologic change. A total of 19 cross sections were surveyed 4 – 6 times between February 2013 and July 2018.

本项目针对加拿大多伦多Wilket Creek一段新近修复的河段，监测粗泥沙运动与河床形态变化，并将其与相邻未修复河段的推移质输运过程进行直接对比。本研究提出了一种修复后河流推移质输运过程的监测方法，其研究结果可为未来河流修复设计提供参考。本研究的数据采集自加拿大多伦多Wilket Creek的未修复河段与修复河段。修复河段的颗粒级配采用沃尔曼卵石计数法（Wolman Pebble count）完成，样本量为200颗卵石。推移质输运过程采用射频识别（Radio Frequency Identification, RFID）示踪卵石开展了为期三年的监测，共投放两批次示踪剂：首批示踪剂于2013年8月投放，未修复河段投放143颗、修复河段投放299颗，涵盖5个粒径级别；第二批示踪剂于2015年8月投放，仅在修复河段投放300颗，涵盖3个粒径级别。在每年野外作业活跃期内，每场主要降雨事件后均记录示踪剂位置，最终累计完成首批示踪剂的10次回收、第二批示踪剂的12次回收。每次回收后，均计算每颗示踪卵石自上次已知位置起的移动距离。针对修复河段开展重复断面测量以监测河床形态变化，2013年2月至2018年7月期间，共对19个河道断面开展了4至6次不等的测量。