Saturated hydraulic conductivity (Ksat) is fundamental to shallow groundwater processes. There is an ongoing need for observed and model validated Ksat values. A study was initiated in a representative catchment of the Chesapeake Bay Watershed in the Northeast USA, to collect observed Ksat and validate five Ksat pedotransfer functions. Soil physical characteristics were quantified for dry bulk density (bdry), porosity, and soil texture, while Ksat was quantified using piezometric slug tests. Average bdry and porosity ranged from 1.03 to 1.30 g/cm3 and 0.51 to 0.61, respectively. Surface soil (0–5 cm) bdry and porosity were significantly (p < 0.05) lower and higher, respectively, than deeper soils (i.e., 25–30 cm; 45–50 cm). bdry and porosity were significantly different with location (p < 0.05). Average soil composition was 92% sand. Average Ksat ranged from 0.29 to 4.76 m/day and significantly differed (p < 0.05) by location. Four models showed that spatial variability in farm-scale Ksat estimates was small (CV < 0.5) and one model performed better when Ksat was 1.5 to 2.5 m/day. The two-parameter model that relied on silt/clay fractions performed best (ME = 0.78 m/day; SSE = 20.68 m2/day2; RMSE = 1.36 m/day). Results validate the use of simple, soil-property-based models to predict Ksat, thereby increasing model applicability and transferability.

Excess nutrients and suspended sediment exports from agricultural watersheds are significant sources of global water quality degradation. An improved understanding of surface water and groundwater pollutant loads is needed to advance practices and policies. A study was conducted in an agricultural-forested catchment of the mid-Atlantic region of the United States. Stream water (SW) and shallow groundwater (SGW) samples were collected monthly between January 2020 and December 2021 from eight sub-catchment study sites. Samples were analyzed for nitrate (NO3-N), nitrite (NO2-N), total ammonia (NH3-N), total nitrogen (TN-N), orthophosphate (PO43-P), and total phosphate (TP-P) concentrations using spectrophotometric methods. Total suspended solids concentrations (mg/L) were quantified gravimetrically and volumetrically to estimate mean particle diameter (MZ, µm), particle surface area (CS, m2/mL), sample skewness (Ski), and particle size distributions (sand/silt/clay%). Results showed significant (p < 0.05) differences in nutrient concentrations and suspended sediment characteristics between SW and SGW between study sites. Differences were attributed to source water type and sub-watershed location. Principal components analysis indicated seasonal effects on water quality in summer months and connected land use with TSS, TN-N, and TP-P concentrations. Study results emphasize the importance of SGW water quality metrics for non-point source loading predictions to inform management decisions in agro-forested watersheds.

Fluvial networks integrate, transform, and transport constituents from terrestrial and aquatic ecosystems. To date, most research on water quality dynamics has focused on process understanding at individual streams, and, as a result, there is a lack of studies analyzing how physical and biogeochemical drivers scale across fluvial networks. We performed tracer tests in five stream orders of the Jemez River continuum in New Mexico, USA, to quantify reach-scale hyporheic exchange during two different seasonal periods to address the following: How do hyporheic zone contributions to overall riverine processing change with space and time? And does the spatiotemporal variability of hyporheic exchange scale across fluvial networks? Combining conservative (i.e., bromide) and reactive (i.e., resazurin) tracer analyses with solute transport modeling, we found a dominance of reaction-limited transport conditions and a decrease of the contributions of hyporheic processing across stream orders and flow regimes. Our field-based findings suggest that achieving knowledge transferability of hyporheic processing within fluvial networks may be possible, especially when process variability is sampled across multiple stream orders and flow regimes. Therefore, we propose a shift in our traditional approach to investigating scaling patterns in transport processes, which currently relies on the interpretation of studies conducted in multiple sites (mainly in headwater streams) that are located in different fluvial networks, to a more cohesive, network-centered investigation of processes using the same or readily comparable methods. Key Points: • Reactive tracer tests revealed reaction-limited conditions along a firstto fifth-order fluvial network during contrasting flow regimes • Processing rate coefficients and Damköhler numbers decreased along the continuum • Results support modeling expectations of decreasing hyporheic contributions along fluvial networksSupporting Information:• Supporting Information S1 regional water quality and ecological functioning (Alexander et al., 2007;Freeman et al., 2007;Gomez-Velez & Harvey, 2014).In addition to making up a larger proportion of catchment reach lengths, low-order streams are thought to have greater influence over hyporheic zone processing than their high-order counterparts throughout various fluvial networks. For example, Gomez-Velez et al. (2015) found that vertical hyporheic excursions into the streambed generally decreased with increasing stream order in the Mississippi River network, meaning that watershed hyporheic contributions to overall riverine processing decreased with increasing stream order over large spatial scales. Additionally, shallower stream depths, typically found in low-order streams, maintain closer contact between surface water and reactive bed sediments and may encourage higher streambed reaction rates (Harvey & Gooseff, 2015). The expectation of decreasing hyporheic zone processing relative to total riverine processing with increasing stream order is in line with hydr...

Ensuring access to safe drinking water is a challenge in many parts of the world for reasons including, but not limited to, infrastructure age, source water impairment, limited community finances and limitations in Federal water protections. Water quality crises and the prevalence of impaired waters globally highlight the need for investment in the expansion of drinking water testing that includes public and private water systems, as well as community outreach. We provide justification including a case example to argue the merits of developing drinking water testing and community outreach programs that include drinking water testing and non-formal education (i.e., public outreach) regarding the importance of drinking water quality testing for human well-being and security. Organizers of drinking water testing programs should: (1) test drinking water quality; (2) develop drinking water quality databases; (3) increase public awareness of drinking water issues; (4) build platforms for improved community outreach; and (5) publish program results that illustrate successful program models that are spatially and temporally transferrable. We anticipate that short-term and intermediate outcomes of this strategy would improve access to drinking water testing, facilitate greater understanding of water quality and increase security through inclusive and equitable water quality testing and outreach programs.