From Construction Sites to Coastal Wetlands: National Erosion and Sediment Control Synthesis and Coastal Vegetation Response to Thin Layer Placement

Abstract

Erosion and sediment control (E&SC) measures play an important role in protecting water quality and preserving ecological balance in a changing environment. Sediment from construction activities can degrade water bodies by blocking sunlight, disrupting aquatic habitats, and transporting pollutants. Stormwater that mobilizes sediments not only reduces water clarity but also impairs the natural functions of receiving waters. Federal initiatives such as the Clean Water Act provide a regulatory framework for controlling these impacts and ensuring that construction operations implement sound pollution prevention measures through techniques like site-specific Stormwater Pollution Prevention Plans (SWPPPs). These measures help manage the flow of sediment into water bodies while balancing development needs with environmental protection. Authorized states have used the flexibility granted by federal legislation to develop their own E&SC practices that reflect local environmental conditions, economic factors, and regional hazards. As a result, there exists a wide range of guidelines and standards, from the design of SWPPPs to the incorporation of best management practices. This state-level variation leads to noticeable differences in how construction stormwater is managed across the nation. The diversity in design approaches and performance metrics highlights the need for a systematic review that can consolidate these practices into a more uniform framework, thereby simplifying evaluation and ensuring consistency in achieving water quality goals. The first component of this dissertation focuses on consolidating and evaluating E&SC practices through the development of a comprehensive database and synthesizing a state-of-the-practice of E&SC practices. By reviewing 176 manuals, standards, and handbooks from 50 states and six territories, the study categorizes these practices using the framework of the Five Pillars of Construction Stormwater Management. The framework organizes practices according to the management of communication, work, water, erosion, and sediment. This systematic analysis revealed that while practices such as vegetated filter strips, temporary slope protections, hydromulches, check dams, silt fence sediment barriers, sediment basins, and dewatering devices/practices, have an abundance of performance data, nearly all other BMPs have minimal or no peer-reviewed performance evaluations to support their effectiveness. The study also highlighted inconsistencies in terminology of BMPs and offers a glossary with a guided structure to improve understanding. Appendices provide a glossary, catalog of BMP names, state-specific summaries, and a compilation of peer-reviewed research by BMP to guide future studies and improve regulatory clarity. The findings reveal the need for targeted research to evaluate under-studied practices and normalize terminology and standards across U.S. states and territories. This systematic analysis identifies methods that are supported by recent performance data as well as those that remain under-studied or outdated. The resulting compilation standardizes terminology and establishes an evidence-based foundation that practitioners and regulators can use to reassess and improve stormwater pollution prevention plans. The insights generated from this effort will assist in streamlining regulatory practices and optimizing the performance of E&SC installations. The second component of the dissertation examines the application of Thin Layer Placement (TLP) for coastal erosion control in the context of living shorelines. Coastal wetlands play an important role in moderating the effects of storms and coastal erosion through natural processes that protect shorelines and support diverse species. In areas such as the Gulf of America, these natural systems are increasingly challenged by sea level rise and human activity. TLP is a sediment management technique that involves applying a thin layer of dredged sediment to areas where natural sedimentation is insufficient. This research focuses on black needlerush (Juncus roemerianus), a native coastal plant known for its robust root system and contribution to shoreline stabilization. Experiments were carried out in a controlled, small-scale marsh environment that simulates coastal conditions found in Alabama. The study used both non-destructive and destructive sampling methods to monitor plant survival, growth, and biomass accumulation across different TLP application depths. The objective was to establish TLP application parameters that preserve plant health and maintain the structure of living shorelines while minimizing the need for replanting. Experiments revealed that J. roemerianus maintained consistent survival and growth under control and 6" TLP treatments, with shoot survival reaching over 80% and shoot length and basal diameter increasing by over 500% in the 6" treatment. The 8" TLP treatment showed early signs of stress but ultimately recovered, achieving over 165% shoot growth. In contrast, the 10", 12", and 14" TLP treatments experienced high mortality with no recovery, with complete burial observed at the highest depths. Biomass trends and root-shoot ratios further displayed the strong growth for lower TLP treatments and stress-induced limitations for higher burial depths. The study found that J. roemerianus can tolerate sediment burial up to approximately 62% of shoot height (8" TLP), but burial beyond 78% (10" or more) compromises survival. These results define a critical TLP application depth threshold for effective living shoreline restoration dominated by black needlerush vegetation. In summary, this dissertation brings together research on inland construction stormwater management and coastal living shorelines to address a broad spectrum of environmental protection. The study offers a comprehensive evaluation of current E&SC practices by identifying state-specific variations and performance gaps that can guide improved policy and implementation strategies. At the same time, the investigation of TLP on living shorelines provides empirical evidence for its effectiveness in sustaining coastal vegetation amid changing environmental conditions. The combined findings strive to enhance our understanding of sediment control from both inland and coastal perspectives and contributes practical, evidence-based guidelines to support more consistent and sustainable environmental management practices.