Gross solids are litter, trash, leaves, and large coarse sediments that travel, either as floating debris or bed loads, in stormwater conveyance systems. Traditional monitoring programs, which were designed to determine the effectiveness of Best Management Practices (BMPs) for reducing stormwater pollution, have relied on autosamplers that ineffectively sample gross solids. These large pollutants can have a harmful impact on the environment. The goal of Guideline for Monitoring Stormwater Gross Solids is to standardize data collection procedures and laboratory protocols used in evaluating the removal of gross solids. Three levels of monitoring procedures are analyzed throughout this report: screening evaluation, performance evaluation, and research and design. This book will be useful to engineers and professionals involved in stormwater management.