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  • Parameterized Statistical Distributions of Unique Origin-Destination Pairs for Major Waterborne Commodity Groups

    Abstract: Modeling the spatiotemporal aspects of freight movements within a distributed network is crucial to forecasting transportation infrastructure needs, prioritizing investments, and estimating emissions. Commodity flow patterns and trends along the inland waterway transportation system are significant because of their importance for the economy, in line with priorities of the US Committee on the Marine Transportation System. Analyzing these inland waterway flows better informs multimodal freight transportation modeling. This exploratory research uncovers, describes, and summarizes patterns and trends of the US waterway transportation system by mining waterborne freight data. The purpose of this work is to identify parameterized statistical distributions that describe the relative dispersion of unique waterborne Origin-Destination (OD) pairs when sorted high to low by annual freight tonnage. Best-fit statistical distributions and associated parameters are identified for the leading commodities transported on waterways, and an 11-year time-series analysis of commodity-specific distribution parameters provide their evolution across time. Results show that the power law best explains the distribution of ranked ODs by tonnage for seven of the twelve commodities analyzed. The root-mean-square error (RMSE) of any given commodity modeled is less than 1%. These results provide insights into the underlying behavior of inland waterway freight transportation.

  • Gremlin Cove Boat Ramp closed due to low water and sediment buildup at Harlan County Lake

    In response to declining lake levels and heavy sediment accumulation, officials at Harlan County Lake have temporarily closed the Gremlin Cove Boat Ramp, effective immediately. This is the largest and most frequently used boat ramp on the lake, and the closure will also impact access to the North Shore Marina.

  • Examining the Impact of the 2007 Zaca Fire on the Long-Term Hydrological Recovery of the Santa Cruz Creek Watershed in Southern California

    Abstract: This study focuses on the Santa Cruz Creek watershed in Southern California, an area severely impacted by the 2007 Zaca Fire. The region is representative of wildfire-prone Mediterranean-climate catchments. We assess long-term post-fire hydrological recovery using a novel dual approach: (1) simulating 16 storm events over a 23-year period to evaluate pre-fire, post-fire, and recovery conditions, and (2) directly comparing two similar storm events—one pre-fire and one during recovery—to isolate changes in watershed response. Hydrological modeling employed HEC-HMS with the Deficit and Constant Loss Method, the ModClark Transform Model, and the Linear Reservoir Baseflow Model. Remote sensing data, including Enhanced Vegetation Index and SERVES Soil Moisture, enhanced modeling and analysis. Vegetation cover, soil moisture, and several watershed parameters show substantial recovery after five years. EVI reached 84 % of pre-fire values, while initial soil moisture deficit, time of concentration, and storage coefficient each recovered to roughly 70 %. Fast baseflow exceeded pre-fire levels at 143 %, but slow baseflow declined to 20 %. Peak discharge and direct runoff volume declined from post-fire highs of 173 % and 136 % to 125 % and 84 % of pre-fire levels, respectively. Although vegetative conditions stabilize, watershed hydrology remains altered.

  • Bioturbation Increases Time Averaging Despite Promoting Shell Disintegration: A Test Using Anthropogenic Gradients in Sediment Accumulation and Burrowing on the Southern California Shelf

    Abstract: Bioturbation increases time averaging of young and old shells within the entire mixed layer and accelerating the burial of shells into a sequestration zone. Bioirrigation by oxygenated pore-water promotes carbonate dissolution in the TAZ, and biomixing itself can mill shells weakened by dissolution or microbial maceration, and/or expose them to damage at the sediment–water interface. We fit transition rate matrices to bivalve age–frequency distributions from four sediment cores to assess the competing effects of bioturbation on disintegration and time averaging. Disintegration covaries positively with mixing at all four sites. Mixing and disintegration rates decline abruptly at the base of the 20- to 40-cm-thick, age-homogenized surface mixed layer at the three well-bioturbated sites. In contrast, they are very low in the upper 25 cm at an effluent site with legacy sediment toxicity. Assemblages formed during maximum wastewater emissions vary strongly in time averaging. Thus, even though disintegration rates covary positively with mixing rates, reducing postmortem shell survival, bioturbation has the net effect of increasing the time averaging of skeletal remains on this warm-temperate siliciclastic shelf.

  • Coastal Sand Dunes: A Review of Management Strategies for Dune Stabilization

    Abstract: The primary objective of this technical note is to provide a US-centric review on historic and current management approaches for dune stabilization efforts. This includes methods for promoting dune formation via natural aeolian processes, as well as more hands-on management approaches, including hybrid dune construction.

  • SandSnap Filtering Techniques

    Abstract: The aim of this Coastal and Hydraulics Laboratory Special Report is to elucidate the new SandSnap image filters. These SandSnap filters distinguish between high-quality and poor-quality images and enhance accuracy in high-quality images. To achieve this goal, a dataset of 5,000 photos was created and curated for this endeavor. Images were collected that had varying levels of focus, sedimentological conditions, foreign objects present, distances from the sediment bed, coin types, and geographic locations. This dataset was used to train multiple quality control check models and uncover beneficial correlations. Additionally, an existing dataset of high-quality images was analyzed using various filtering techniques to highlight key features, leading to higher-accuracy scores. Using the findings from both the high-quality and poor-quality datasets, SandSnap was updated to increase usability and efficiently identify images that may lead to poor results. This ensures that user results can be calculated in less than a minute, emphasizing the commitment to maintaining a fast and responsive model.

  • Corps of Engineers: Navigating Puerto Rico's Maritime Future

    Every safe arrival and departure from the numerous harbors in Puerto Rico is made possible by a team of professionals working quietly but relentlessly to ensure Federal navigation channels are open, secure, and ready for whatever comes next. To ensure the continued safety of these harbors, in July 2025, the U.S. Army Corps of Engineers Caribbean District Operations Branch – in partnership with the Charleston District – carried out hydrographic surveys at the Harbors of Ponce, Mayagüez, and Arecibo. These surveys were not just routine; they were a vital part of the Corps’ mission to maintain safe navigation and interstate commerce across the region.

  • USACE announces public workshops for farmers in the White River basin

    The U.S. Army Corps of Engineers will host two workshops from 5 to 7 p.m. Sept. 2 and 3 to meet with lower White River Basin farmers and discuss this year’s spring and summer flooding and the White River Water Control Plan.

  • Vegetation control to begin on Missouri River sandbars between Garrison Dam and Huff, N.D.

    The U.S. Army Corps of Engineers will conduct vegetation management activities during August and September on sandbars in the Missouri River between Garrison Dam and Huff, North Dakota. The Bismarck-Mandan river reach (river miles 1325 to 1310) will not be sprayed. This work is being done to keep the sandbars free of vegetation and usable by the threatened piping plover for nesting.

  • Vegetation control to begin on Missouri River sandbars between Yankton and Vermillion, S.D.

    During September, the U.S. Army Corps of Engineers will conduct vegetation management activities on sandbars in the Missouri River between Yankton and Vermillion, South Dakota, the upper portion of Lewis and Clark Lake near Springfield South Dakota and Niobrara, Nebraska, and as far upstream as Pickstown, South Dakota. This work is being done to keep the sandbars free of vegetation and usable by the threatened piping plover for nesting as well to control invasive common reed that has become prevalent in the lake area.