Gregory B. Noe Rebecca R. Murphy 20250521 tabular digital data Reston, VA U.S. Geological Survey https://doi.org/10.5066/P14AJH9J Gregory B. Noe Rebecca R. Murphy Ken W. Krauss 2025 publication Manuscript submitted for publication to a journal Results of statistical analyses of nontidal and tidal station measurements of suspended sediment concentrations in the Chesapeake Bay and watershed, collected from 1984-2021 by Chesapeake Bay Program and partners and the U.S. Geological Survey. Original measurements were retrieved from online data repositories. To identify spatial and temporal patterns in suspended sediment concentration changes across tidal and salinity gradients over multiple tidal rivers of the Chesapeake Bay and watershed. 19840101 20210625 ground condition Complete None planned Chesapeake Bay and watershed -78.2062 -75.5667 40.0510 36.6772 None Tidal freshwater Oligohaline Mesohaline Polyhaline Nontidal USGS Thesaurus sediment transport estuarine processes suspended material (water) salinity USGS Metadata Identifier USGS:68029110d4be0210cdcc988b Common geographic areas Lower Chesapeake Bay Upper Chesapeake Bay No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Common CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Gregory Noe USGS - Florence Bascom Geoscience Center Research Ecologist mailing and physical

1289 Mcd Drive

Dover DE 19901 571-748-9610 gnoe@usgs.gov The Chesapeake Bay Program’s Water Quality Monitoring Program (http://datahub.chesapeakebay.net/WaterQuality) began in 1984 with hundreds of tidal stations sampled through Maryland, Virginia, and Washington DC’s monitoring programs. The U.S. Geological Survey and partners collect discharge and sediment concentrations at stations throughout the watershed of the Chesapeake Bay (https://waterdata.usgs.gov/nwis). Funding support was provided by the USGS Chesapeake Bay Activities program. We would like to acknowledge the contributions of Rebecca Murphy, Ken Krauss, and the states of Maryland and Virginia, and Washington, D.C., for their data collection efforts and for providing the General Additive Model (GAM) results. Environment as of metadata creation: Microsoft Windows 11 Enterprise version 23H2 (OS build 22631.4602). Microsoft® Excel® for Microsoft 365 MSO (Version 2408 Build 16.0.17928.20512) 64-bit. JMP v18.2.0. No formal attribute accuracy tests were conducted. Results of General Additive Model (GAM) statistical analyses are presented as provided by Maryland, Virginia, and Washington DC’s monitoring programs. No formal logical accuracy tests were conducted. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the entire metadata record carefully for additional details. Scott W. Ator 2019 publication n/a U.S. Geological Survey https://doi.org/10.3133/sir20195118 Digital and/or Hardcopy 19991001 20140931 ground condition SPARROW Predictions of suspended sediment annual load for river reaches U.S. Geological Survey 2025 application/service https://waterdata.usgs.gov/nwis Digital and/or Hardcopy 1984 2022 ground condition NWIS Suspended sediment concentration and discharge data for nontidal river gage stations Chesapeake Bay Program 2025 tabular digital data http://datahub.chesapeakebay.net/WaterQuality Digital and/or Hardcopy 1984 2022 ground condition CBP Suspended sediment concentration and salinity data for tidal stations Data were downloaded from the Chesapeake Bay Program and U.S. Geological Survey, processed, and then analyzed for statistical metrics and summaries in JMP or Excel. For tidal stations, only data from the "surface" layer of the water column was analyzed. 20250401 Gregory Noe USGS - Northeast Region Research Ecologist mailing and physical

1289 Mcd Drive

Dover DE 19901 571-748-9610 gnoe@usgs.gov Chesapeake suspended sediment data.csv Comma Separated Value (CSV) file containing data. Producer Defined Station Identifying code for each water quality monitoring station Producer Defined Unique station identifier from Chesapeake Bay Program's Water Quality Monitoring Program or the U.S. Geological Survey's National Water Information System. Tidal_river_ID Name of the tidal river where the station is located Producer Defined NM Station is not located along a tidal river Producer defined Tidal river name. River_gage_name Name of nontidal river gage Producer Defined NM Station is tidal and therefore there is no river gage associated with the station. Producer defined Full name of nontidal river gages provided in U.S. Geological Survey's National Water Information System. Distance_from_head-of-tide River distance from station to the head-of-tide along that river, in units of kilometers (km). Producer Defined NM Station is not along a tidal river, or is located along a tidal river but not nearest the head-of-tide Producer defined 0.3 73 km Station_setting Hydrologic and salinity setting of the station. Producer Defined 1 Nontidal river Producer defined 2 Tidal river Producer defined 3 Tidal other Producer defined 4 Insufficient suspended sediment data sample size Producer defined Latitude Latitude of station Producer Defined 36.73611 40.0545413 degrees Longitude Longitude of station Producer Defined -78.0858328 -75.3244444 degrees Salinity_sample_size Number of salinity samples collected Producer Defined NM Salinity not measured Producer defined 0 733 number Salinity_mean Mean salinity, in units of practical salinity units (psu) Producer Defined NM Salinity not measured Producer defined 0 27.2 psu Salinity_CV Coefficient of variation of salinity, in units of practical salinity units (percentage) Producer Defined NM Salinity not measured Producer defined 0 2439.3 % Salinity_zone Salinity and hydrology description based on the mean salinity and nontidal versus tidal hydrology. Producer Defined Nontidal freshwater; nontidal Producer defined Oligohaline Mean salinity between 0.5 and 5 psu; tidal Producer defined Mesohaline Mean salinity between 5 and 18 psu; tidal Producer defined Tidal Fresh Mean salinity less than 0.5 psu; tidal Producer defined Polyhaline Mean salinity between 18 and 30 psu; tidal Producer defined NM Not measured (tidal, but not along a tidal river) Producer defined TSS_or_SSC_sample_size Number of suspended sediment samples collected Producer Defined 1 1122 number TSS_or_SSC_mean Mean suspended sediment concentration, in units of milligrams per liter (mg/L) Producer Defined 5.0 249.7 mg/L TSS_or_SSC_CV Coefficient of variation of suspended sediment concentration, in units of milligrams per liter (percentage). Producer Defined NM could not be calculated due to sample size = 1 Producer defined 20.4 381.7 % SPARROW_suspended_sediment_load Nontidal river's annual suspended sediment load, estimated by the SPARROW model, in units of megagrams per year (Mg/yr; Ator et al. 2019) Producer Defined NM No load estimated. Producer defined 1456 4304088 Mg/yr Nontidal_log-log_flow-SSC_regression_slope Slope of the linear regression of (log10-transformed) discharge and (log10-transformed) suspended sediment concentration Producer Defined NM Not analyzed Producer defined 0.2884 1.3493 Nontidal_log-log_flow-SSC_regression_R2 Coefficient of determination (R2) of the linear regression of (log10-transformed) discharge and (log10-transformed) suspended sediment concentration Producer Defined NM Not analyzed Producer defined 0.0527 0.7093 Nontidal_log-log_flow-SSC_relationship_strength Strength and directionality of the relationship between suspended sediment and discharge at nontidal stations Producer Defined NM Not analyzed Producer defined strong increase Suspended sediment increases strongly with increasing discharge Producer defined weak increase Suspended sediment increases weakly with increasing discharge Producer defined NM Not analyzed Producer defined Tidal_GAM_hydroTermSel Indicator for whether nontidal freshwater flow (flow) or tidal station measured salinity was used for models with term "flw_sal" (flow/salinity) in the General Additive Model (GAM) of tidal suspended sediment concentration Producer Defined NM Not analyzed Producer defined flow Flow (nearby nontidal discharge) was used in the model Producer defined salinity Salinity was used in the model Producer defined Tidal_GAM_hydroTermSel.var Indicator of which flow or salinity metric was used in models with "flw_sal" (flow/salinity) term in the General Additive Model (GAM) of tidal suspended sediment concentration Producer Defined NM Not analyzed Producer defined d120 nearest river freshwater discharges averaged over the antecedent 120 days Producer defined d150 nearest river freshwater discharges averaged over the antecedent 150 days Producer defined d1 nearest river freshwater discharges averaged over the antecedent 1 day Producer defined d90 nearest river freshwater discharges averaged over the antecedent 90 days Producer defined d60 nearest river freshwater discharges averaged over the antecedent 60 days Producer defined d210 nearest river freshwater discharges averaged over the antecedent 210 days Producer defined SAP simultaneously measured salinity Producer defined d180 nearest river freshwater discharges averaged over the antecedent 180 days Producer defined d30 nearest river freshwater discharges averaged over the antecedent 30 days Producer defined d5 nearest river freshwater discharges averaged over the antecedent 5 days Producer defined d10 nearest river freshwater discharges averaged over the antecedent 10 days Producer defined Tidal_GAM_usgsGageID USGS nontidal gage IDcode used in models with "flw_sal" (flow/salinity) term in the General Additive Model (GAM) of tidal suspended sediment concentration Producer Defined NM not analyzed Producer defined USGS gage station identifier Tidal_GAM_usgsGageName USGS nontidal gage name used in models with "flw_sal" (flow/salinity) term in the General Additive Model (GAM) of tidal suspended sediment concentration Producer Defined USGS gate station name Tidal_GAM_Flw_Sal_directionality Summary of directionality of the effect of flow or salinity on suspended sediment concentration in the General Additive Model (GAM) of tidal suspended sediment concentration. The inverse of the relationship between suspended sediment and salinity is presented to represent freshwater flow effects Producer Defined NM Not analyzed Producer defined Decrease suspended sediment decreases with increasing freshwater flows Producer defined Increase suspended sediment increases with increasing freshwater flows Producer defined No change suspended sediment does not change with increasing freshwater flows Producer defined Tidal_GAM_Flw_Sal_strength_(1_threshold) Summary of the strength of the effect of flow or salinity on suspended sediment concentration in the General Additive Model (GAM) of tidal suspended sediment concentration. The inverse of the relationship between suspended sediment and salinity is presented to represent freshwater flow effects Producer Defined NM Not analyzed Producer defined med-weak suspended sediment weakly-to-moderately changes with increasing freshwater flows Producer defined weak suspended sediment weakly changes with increasing freshwater flows Producer defined strong suspended sediment strongly changes with increasing freshwater flows Producer defined Tidal_GAM_s.flw_sal.pv General Additive Model (GAM) smoothed p-value for "flw_sal" (flow/salinity) term Producer Defined NM Not analyzed Producer defined 0 0.565922274 Tidal_GAM_ti.flw_sal.doy General Additive Model (GAM) smoothed trend interaction "[ti(flw_sal,doy)]" (flow/salinity and day-of-year) term p-value Producer Defined NM Not analyzed Producer defined 0 0.914214834 Tidal_GAM_ti.flw_sal.cyear General Additive Model (GAM) smoothed trend interaction "[ti(flw_sal,cyear)]" (flow/salinity and year) term p-value Producer Defined NM Not analyzed Producer defined 0 0.95701352 Tidal_GAM_ti.flw_sal.doy.cyear General Additive Model (GAM) smoothed trend interaction "[ti(flw_sal,doy,cyear)]" (flow/salinity and day-of-year and year) term p-value Producer Defined NM Not analyzed Producer defined 0 0.963246719 Tidal_GAM_por.bl.mn.obs General Additive Model (GAM) estimated mean suspended sediment concentration at the baseline (start of record) of the period of record, in units of milligrams per liter (mg/L) Producer Defined NM Not analyzed Producer defined 4.230391737 47.06267787 mg/L Tidal_GAM_por.cr.mn.obs General Additive Model (GAM) estimated mean suspended sediment concentration at the current timeframe (end of record) of the period of record, in units of milligrams per liter (mg/L) Producer Defined NM Not analyzed Producer defined 3.2593737 47.93635767 mg/L Tidal_GAM_por.abs.chg.obs General Additive Model (GAM) estimated change in suspended sediment concentration over the period of record, in units of milligrams per liter (mg/L) Producer Defined NM Not analyzed Producer defined -15.94738316 14.89511492 mg/L Tidal_GAM_por.pct.chg General Additive Model (GAM) percent change in suspended sediment concentration over the period of record, in percent (%) Producer Defined NM Not analyzed Producer defined -66.20938185 62.00670247 % Tidal_GAM_por.chg.pv General Additive Model (GAM) p-value for percent change in suspended sediment concentration over the period of record Producer Defined NM Not analyzed Producer defined 0 0.972491449 Tidal_GAM_adjR2 General Additive Model (GAM) adjusted R-squared value (Coefficient of determination; R2) Producer Defined NM Not analyzed Producer defined 0.0948 0.7705 Tidal_GAM_yearBegin General Additive Model (GAM) year of the beginning of record analyzed Producer Defined NM Not analyzed Producer defined 1999 2000 year Tidal_GAM_yearEnd General Additive Model (GAM) year of the end of record analyzed Producer Defined NM Not analyzed Producer defined 2022 2022 year U.S. Geological Survey - ScienceBase mailing address

Denver Federal Center

Building 810

Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P14AJH9J. None 20250521 Gregory Noe USGS - Northeast Region Research Ecologist mailing and physical

1289 Mcd Drive

Dover DE 19901 571-748-9610 gnoe@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999