Geology topics

Brittany R. Hanrahan

Publications and source records attributed to Brittany R. Hanrahan.

4 recordsLinked to original sources

USGS2026

Evaluating bank restoration and stabilization in the Yellow River in northern Indiana: Mitigation of sediment and nutrient transport

The U.S. Geological Survey, in cooperation with the Kankakee River Basin and Yellow River Basin Development Commission, evaluated the effects of streambank remediation on the Yellow River in northwest Indiana. Two phases of remediation were completed on the Yellow River between 2021 and 2023, after assessments indicated it was a large contributor of sediment to the Kankakee River. Temporal effects were assessed using pre‑remediation (April 2019 –October 2021) and post‑remediation (February – October 2024) data from two long‑term monitoring sites, USGS 05516665 Yellow River near Oak Grove (Oak Grove) and USGS 05517000 Yellow River at Knox (Knox). Spatial patterns were evaluated among sites from upstream to downstream during the post-remediation period. Monitoring included the pre-existing Oak Grove and Knox sites, an additional monitoring site at USGS streamgage 05516500 Yellow River at Plymouth (Plymouth), and discrete sampling at two additional sites. Discrete sites include USGS 05516663 Yellow River at Upas Rd near Oak Grove (Upas Rd), located upstream of the remediation reach, and USGS 05516667 Yellow River at CR11100E near Oak Grove (CR1100E), located within the remediation reach. Generalized least squares and linear mixed‑effects regression models were used to evaluate temporal differences in turbidity-to-discharge relations for slope and turbidity units, discharge, and suspended‑sediment in before and after remediation data. Similar analysis using generalized least squares and linear mixed‑effects regression models were conducted for spatial analysis of discharge and sediment and nutrient concentrations and fluxes at each site post-remediation. Temporal comparisons showed that turbidity increased less with discharge increases after remediation, indicated by slope of relation, at both Oak Grove and Knox, indicating improved water clarity during higher flows. Mean turbidity and suspended‑sediment concentrations were not statistically different between remediation periods. Comparison of the post-remediation continuous water quality data from upstream to downstream sites through the remediated reaches indicated that downstream sites exhibited steeper turbidity‑to‑discharge slopes than the upstream control site at Plymouth. A statistically significant difference was detected between the slopes at Oak Grove and Plymouth, whereas Knox did not differ significantly from either Plymouth or Oak Grove. Downstream sites had significantly lower mean turbidity, suggesting improved water clarity within and downstream of the remediation reach. Nutrient concentrations generally decreased moving downstream and suspended‑sediment concentrations showed no consistent trend. Nutrient and sediment fluxes increased downstream, likely reflecting the influence of greater discharge volumes. Interpretation of remediation effects was limited by the absence of pre‑remediation data at upstream sites and by the short post‑remediation monitoring period. Continued monitoring could allow for assessment of longer‑term responses to streambank remediation on the Yellow River, as effects may become more pronounced over time.

EarthArXiv↗

USGS2026

Evaluation of best management practices at an edge-of-field site in the Eagle Creek watershed, Ohio, 2012–20

In 2010, the U.S. Geological Survey worked in partnership with the Great Lakes Restoration Initiative and the Natural Resources Conservation Service to identify farm fields in priority watersheds—watersheds critically important to Great Lake health. Intensive best management practices were implemented in five States to test the efficacy of best management practices, also referred to as agricultural conservation practices, to reduce sediment and nutrient runoff on agricultural fields. These fields were chosen as representatives of the priority watersheds because their farming practices and geographical conditions were common among farms in those watersheds. A farm site located near Findlay, Ohio, in the Eagle Creek watershed used two conservation practices, cover crop (Natural Resources Conservation Service practice standard 340) and variable rate technology (VRT; Natural Resources Conservation Service practice standard 590), which represent common practices in the Maumee priority watershed. This study monitored surface runoff and subsurface tile runoff at the Eagle Creek watershed site. The effects of cover crop and VRT nutrient application on sediment and nutrient runoff were assessed from October 2012 to September 2020. Cover crops were applied in fall of 2016, 2017, and 2018, coinciding with VRT applications. The following parameters were analyzed as part of the study: runoff discharge; peak discharge; and concentrations and loads of total phosphorus, particulate phosphorus, dissolved reactive phosphorus, and suspended sediment. High peak runoff events disproportionally affected nutrient concentrations and loads in runoff. A threshold of the 85th percentile of the peak discharge was chosen to assess the effect of cover crop and VRT nutrient application on nutrient mitigation at each gage. Runoff events below the 85th percentile were considered small, and runoff events over the 85th percentile were considered large. Concentrations from collected water-quality samples were used for the analysis; estimated concentrations were excluded from the statistical evaluation. All surface runoff parameters during small runoff events, except surface runoff volume, were significantly lower in the period with cover crops and VRT implementation. Contrarily, subsurface runoff parameters during small events were not statistically different between the periods with and without cover crops and VRT implementation. Surface and subsurface parameters during large events were also not statistically different between the periods with and without cover crops and VRT implementation. These results indicate cover crops and VRT may improve water quality during small runoff events, but additional best management practices that mitigate large runoff events may lead to greater water-quality improvement given the contribution of large events to overall losses.

Ohio↗

USGS2026

Assessing the influence of conservation implementation on water quality during surface runoff events at edge-of-field monitoring sites located in the Laurentian Great Lakes basin

The Laurentian Great Lakes are a vital freshwater resource in the United States, and nonpoint source (NPS) nutrient pollution, specifically phosphorus (P) and nitrogen (N), from agricultural land use continues to negatively impact water quality throughout the Great Lakes basin. One focus of the Great Lakes Restoration Initiative (GLRI), a mechanism to coordinate conservation efforts in the Great Lakes that began in 2010, is reducing NPS nutrient pollution through the implementation of conservation practices in priority watersheds (Genesee River, Fox River, Maumee River, and Saginaw River). As part of GLRI efforts, the objective of the study presented here was to evaluate the effects of conservation implementation, specifically increasing vegetative cover on fields and in primary flowpaths through perennial or cover crop planting and grassed waterways, on surface-runoff water quality at 12 agricultural fields (six paired and six unpaired) located in priority watersheds. We determined the percentage difference in mean event response variables between the periods before and after conservation implementation at individual sites, describing patterns across sites to synthesize lessons learned from these GLRI evaluations. Generally, we found that mean event flow-weighted concentration (FWC) and yield (kilograms per hectare) decreased for suspended sediment (SS) and nitrate (NO 3 – -N) across many sites. Mean event FWC and yield for total P (TP) showed mixed results across sites, while mean event FWC and yield for orthophosphate generally increased across sites. These results indicate that perennial or cover crop planting and grassed waterways effectively reduce SS and NO 3 – -N losses in surface runoff from agricultural fields, but mitigating TP and dissolved P losses remains a challenge.

Laurentian Great Lakes basin↗

USGS2023

Importance of dense aquatic vegetation in seasonal phosphate and particle transport in an agricultural headwater stream

Agricultural headwater streams and ditches commonly host dense stands of aquatic vegetation that grow and decay over seasons and exert physical and biological controls on the transport of nutrients from cropland to larger rivers. This study examined changes in the transport of phosphorus (P) in an agricultural drainage ditch in the Maumee River Basin (Ohio, USA) by conducting constant rate injections of a novel tracer mixture (conservative salt [Cl as NaCl], dissolved P [KH 2 PO 4 ], and a fluorescent fine particle) in spring, summer, and fall. We quantified transport behavior for solutes and particles using a traditional transient storage modeling framework consisting of mobile and immobile storage zones connected by a first-order exchange rate constant. Transient storage was greatest during the spring, when thicker vegetation caused more pooling and flow stagnation, and decreased through fall, as vegetation thinned. Soluble P uptake lengths were 8.7 times longer in fall than spring, likely due to declines in biological uptake rates with colder temperatures and immobile zone storage with thinning vegetation. Particle capture lengths also decreased by a factor of 4.3 from fall to spring. With the increasing eutrophication of Lake Erie and waterbodies around the world that lie downstream from agricultural landscapes, it is beneficial to understand nutrient transport across watersheds, including small agricultural streams. This study highlights the physical and biological roles that aquatic vegetation plays in small agricultural streams by creating seasonally variable immobile zones that slow the flow of nutrients, providing surface area for biofilms, and capturing particles that bind nutrients.

Water Resources Research↗