Hydrologic site assessment for passive treatment of groundwater nitrogen with permeable reactive barriers, Cape Cod, Massachusetts

Jeffrey R. Barbaro; Marcel Belaval; Danna B. Truslow; Denis R. LeBlanc; Thomas C. Cambareri; Scott C. Michaud

doi:10.3133/sir20195047

Home/Archive/USGS

USGS · sir20195047

Hydrologic site assessment for passive treatment of groundwater nitrogen with permeable reactive barriers, Cape Cod, Massachusetts

Jeffrey R. Barbaro·Marcel Belaval·Danna B. Truslow·Denis R. LeBlanc·Thomas C. Cambareri·Scott C. Michaud

View original source ↗Read source document ↗Export metadata ↓

Abstract

Wastewater disposal associated with rapid population growth and development on Cape Cod, Massachusetts, during the past several decades has resulted in widespread contamination of groundwater with nitrogen. As a result, water quality in many of the streams, lakes, and coastal embayments on Cape Cod is impaired by excess nitrogen. To reduce nitrogen loads to these impaired water bodies, watershed-based planning is currently [2019] underway following a regional strategy, the section 208 areawide water-quality management plan update for Cape Cod. In the updated plan, traditional (sewering) and alternative wastewater management options are under consideration for restoring water quality in impaired surface-water bodies. Permeable reactive barriers, which are reactive zones emplaced below the water table for passive treatment of groundwater contaminants, are one of the alternatives being considered by Cape Cod towns as a potentially cost-effective technology for the removal of nitrogen from groundwater. However, the effectiveness of permeable reactive barriers depends on local conditions, and site-specific hydrologic and water-quality data are needed to inform the decision to install a permeable reactive barrier in a given location. These data are not available in most locations on Cape Cod; consequently, site assessments are needed before selecting this treatment option. To address this need, the U.S. Environmental Protection Agency, U.S. Geological Survey, and Cape Cod Commission formed a technical team in 2015 to develop and evaluate a hydrologic site-assessment approach for permeable reactive barrier installation. The approach developed by the technical team includes a preliminary regional assessment followed by a phased onsite investigation. The approach was intended to provide the hydrologic data needed to make informed decisions on site suitability and to support installation and monitoring should the site be deemed appropriate for a permeable reactive barrier. The factors that were evaluated to characterize local hydrologic conditions and inform site selection included groundwater flow directions and rates, depth to the water table, hydraulic conductivity and degree of heterogeneity of the aquifer, spatial distribution and concentration of nitrate and oxidation-reduction-sensitive constituents, thickness and depth of the treatment zone, distance to downgradient water bodies, and access for drilling and permeable reactive barrier installation. The approach was demonstrated on Cape Cod by conducting a preliminary assessment of 27 sites, from which 5 sites were selected for onsite investigations. Results indicated that the site-assessment approach was successful for screening sites and characterizing the geologic, hydrologic, and water-quality conditions at the sites selected for onsite investigations. Overall, the phased assessment evaluated in this study provided an efficient means of obtaining the hydrologic information needed to determine if a site was suitable for permeable reactive barrier installation on Cape Cod for the passive treatment of nitrogen in groundwater.

Explore related subjects

Scientific Investigations Report Report

Source-reported bounding extent: 41.409775832009565° to 42.08803181932636° latitude; -70.94970703125° to -69.92523193359375° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Jeffrey R. Barbaro, Marcel Belaval, Danna B. Truslow, Denis R. LeBlanc, Thomas C. Cambareri, Scott C. Michaud. 2019-07-02. Hydrologic site assessment for passive treatment of groundwater nitrogen with permeable reactive barriers, Cape Cod, Massachusetts. https://doi.org/10.3133/sir20195047

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Monitoring recreation on federally managed lands and waters—Aspects of visitor use

Federally managed public lands and waters receive around 1 billion recreational visits each year. Data on these visitors can aid in guiding policy decisions, managing resources effectively, and communicating the economic contributions of lands and waters. This report explores the methods used by agencies to collect data on aspects of recreational visitor use to Federal lands and waters (apart from visitation numbers, which are the focus of a companion publication). Aspects of recreational visitor use include visitor demographics, recreational activity participation, visitor satisfaction, visitor attitudes and experiences, trip characteristics, and economic contributions. We review practices used to understand aspects of visitor use across seven Federal agencies, revealing similarities such as the use of visitor intercept surveys and coverage of similar topic areas, and differences in how survey programs are operationalized and how specific questions on visitor surveys are worded. We also evaluate emerging technologies, such as geolocated social media and mobile device location data, for their potential to aid in understanding aspects of visitor use. This report concludes with potential opportunities to enhance data collection and coordination, ensuring cost-effective data collection and informed decision making.

Scientific Investigations Report↗

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

Continuous monitoring and temporal variability of fluorescence of dissolved organic matter in karst groundwater of the Edwards aquifer, south-central Texas, 2019–24

Widespread urbanization on the Edwards aquifer recharge zone in south-central Texas has prompted the development of new approaches and tools for evaluating the current and future status of water quality in the San Antonio and Barton Springs segments of the Edwards aquifer. The U.S. Geological Survey, in cooperation with the San Antonio Water System and the City of Austin, applied continuous monitoring of fluorescence of dissolved organic matter (fDOM) to characterize the sources and transport of dissolved organic matter and associated constituents in the Edwards aquifer. Continuous fDOM time-series data were adjusted using empirically derived temperature, turbidity, and inner-filter-effect correction factors prior to analysis and interpretation. Fully corrected fDOM time-series data from the study sites were evaluated for short- and long-term temporal variability in fDOM in the context of the hydrologic and climatic conditions that occurred during the 5-year study period to understand vulnerability of the aquifer to potential contaminants in recharge. Study results indicate that fDOM is an effective proxy for dissolved organic carbon that, in turn, is indicative of the influx of recent surface water and associated contaminants, and thus, aquifer vulnerability to those contaminants. Although other continuously monitored water-quality parameters provide insights into changes in water quality in response to varying hydrologic conditions, the quantitative relation between fDOM and dissolved organic carbon directly indicates the timing and magnitude of pulses of organic constituents derived from the land surface, whereas other water-quality parameters do not.

Texas↗