James Tributary Summary
A summary of short and long-term trends in tidal water quality and associated factors.
Tributary Summaries
The Integrated Trends Analysis Team produces tributary summaries for the Chesapeake Bay’s twelve major tributaries using tidal monitoring data. This data is collected from more than 130 monitoring stations throughout the mainstem and tidal portions of the Bay. These summaries use water quality sample data to:
- Investigate how tidal water quality (total nitrogen, total phosphorus, dissolved oxygen, chlorophyll a, Secchi depth) has changed over time.
- Identify which factors may influence water quality changes over time.
- Determine how those factors influence water quality.
Chesapeake Bay Watershed
The Chesapeake Bay watershed covers 165,760 square kilometers over six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and Washington, D.C. The largest rivers that flow through the watershed are the Susquehanna River, Potomac River, James River, Rappahannock River, and York River. Over 100,000 tributaries reach across the Chesapeake Bay watershed.
More information about the Chesapeake Bay and programs for its restoration can be found on the Chesapeake Bay Program website . Technical data, such as tidal data and water quality parameters, are available through the Chesapeake Bay Watershed Data Dashboard .
Physiography
Physiography describes the Earth’s surface based on the predominant types of landforms found in each region. The James River watershed stretches across five major physiographic regions, namely, the Valley and Ridge, Blue Ridge, Piedmont, Mesozoic Lowland, and Coastal Plain. The Coastal Plain physiography covers lowland, dissected upland, and upland areas.
Land Use
In general, developed lands in 2001 were more concentrated within towns and major metropolitan areas. Since 2001, developed and semi-developed lands have expanded around these urban areas, as well as extending into previously undeveloped regions. This is demonstrated in the map on the right which uses impervious surface coverage to represent developed lands.
The gray area shows where the land was covered by impervious surfaces in 2001, whereas the red area shows impervious surfaces developed between 2002 and 2019. The proportion of land in the James watershed classified as urban rose from 7% in 1985 to 12% in 2022 as identified in the Chesapeake Assessment Scenario Tool (CAST).
The impacts of land development on water quality depend on land use. In general, an increase in urbanization and paved surfaces increases stormwater runoff, leading to more nutrients and sediments entering rivers and streams.
Bay 101: Stormwater Runoff
Water Quality Status
Dissolved Oxygen (DO) Standards
Multiple water quality standards have been developed for tidal waters in the Chesapeake Bay to protect aquatic living resources' habitats. These standards include specific criteria for dissolved oxygen (DO), chlorophyll a, and water clarity/underwater bay grasses. For example, this figure shows the DO concentrations in milligrams per liter necessary for the survival of these aquatic species.
Designated Uses for Chesapeake Bay Waters
These water quality standards are different, however, depending on where you are at in the Bay. This figure shows how under the Clean Water Act, water quality standards depend on the associated designated use of these waters by aquatic species, which often corresponds with certain geographic characteristics.
Chesapeake Bay Segmentation Scheme
The Chesapeake Bay Program has split the Bay into 92 segments, each having one or more designated uses (see the above section) based on its biophysical characteristics. Each segment is monitored for how well each of its designated uses meet water quality criteria standards. The map on the right shows the location of each water quality segment in the Chesapeake Bay Program segmentation scheme. Click on a segment to see which designated use that body of water supports and is evaluated for the water quality criteria.
Monitoring is Critical for Assessing Water Quality Status
Water quality monitoring is critical to determine if water quality standards are being met in the Chesapeake Bay and its tributaries. This video shows how water quality monitoring is conducted. Without water quality monitoring, it is difficult to ascertain the current condition of the Bay or if the health of the Bay is improving.
Dissolved Oxygen (DO) Attainment for the James
The James is composed of several tidal segments grouped by their salinity (i.e., Tidal Fresh and the suffix -haline) and geography, which can be located on the interactive map above:
- Appomattox River Tidal Fresh (APPTF)
- Chickahominy River Oligohaline (CHKOH)
- James River Tidal Fresh (JMSTF1, JMSTF2)
- James River Oligohaline (JMSOH)
- James River Mesohaline (JMSMH)
- James River Polyhaline (JMSPH)
- Elizabeth River and its Eastern, Southern, and Western branches, including the Lafayette River (ELIPH, EBEMH, SBEMH, WBEMH, LAFMH)
The figure on the right is an example of how well these segments of the James met DO criterion over time. A value of zero on the graph means DO criteria are met (attainment) for that designated use and a negative value means the criteria are not met (non-attainment) and by how much (attainment deficit). The designated uses displayed on these graphs (Open Water, Deep Water, Deep Channel) correspond with the figure above describing the five designated uses. The number in the white box represents Mann-Kendall trend results, where ** indicates statistically significant values.
In general, Open Water (OW) criterion was at or near zero from the start of monitoring to the most recent assessment period covered by this report (2020-2022) in five segments, namely, APPTF, JMSMH, JMSOH, JMSPH, and JMSTF2. By contrast, the other segments showed a high degree of variability with four segments (CHKOH, ELIPH, JMSTF1, LAFMH) attaining the criterion in some assessment periods and three segments (EBEMH, SBEMH, WBEMH) never achieving that status. The Deep Water (DW) criterion was applicable to only one segment, i.e., SBEMH, which showed large deficits in the early periods (about -30%) and more frequent occurrences of full attainment in the recent periods. Mann-Kendall trend results indicated two statistically significant trends, i.e., long-term improvements in JMSTF1 OW-DO and SBEMH DW-DO.
Status and Trends for Dissolved Oxygen (DO) Criterion Attainment in the James
In addition to seeing whether a segment of the James meets a criterion, it is helpful to see if a segment is improving by measuring trends (see "Dissolved Oxygen (DO) Attainment for the James" for the list of segment names and see "Chesapeake Bay Segmentation Scheme" for where those segments are located). The maps to the right show trends in the DO concentrations from 1985 - 2022 at monitoring locations along with the status of the water quality criterion from 2020 - 2022. Overlaying DO concentration trends with the water quality criterion status can provide valuable information such as the progress towards meeting a criterion that has not been met yet, or the possibility that conditions are degrading even if the criterion is currently being met.
The bottom depths at each of these stations is different due to varying bathymetry, but the bottom DO trends at these stations are expected to represent water in the DW designated use. Notably the DO concentrations both in the surface and the bottom are improving at most of the Elizabeth River region stations, suggesting progress even in segments not meeting the DW and OW summer 30-day mean DO criteria.
Long-Term Water Quality Parameters (1985-2022)
All short (10 years of data) and long-term (from 1985 to the most recent year of available data) trends are adjusted for flow to explain some variation in the water quality parameters. This allows for better measurement of the results of management actions by accounting for seasonality and precipitation.
Total Nitrogen (TN)
= Decreasing Nitrogen Concentration = Improving Water Quality
= Increasing Nitrogen Concentration = Degrading Water Quality
For annual total nitrogen, all stations are improving.
Click on the trend symbol of the map to show the station name and percent change.
Total Phosphorus (TP)
= Decreasing Phosphorus Concentration = Improving Water Quality
= Increasing Phosphorus Concentration = Degrading Water Quality
For annual total phosphorus, a majority of stations in each salinity zone display improving trends.
Surface Chlorophyll a: Spring
= Decreasing Chlorophyll a Concentration = Improving Water Quality
= Increasing Chlorophyll a Concentration = Degrading Water Quality
Measuring chlorophyll a in the Chesapeake Bay indicates the abundance of phytoplankton. In a balanced ecosystem, phytoplankton provide food for fish, crabs, oysters, and worms. When too many nutrients are available, phytoplankton may grow unchecked and form algal blooms that can harm fish, shellfish, mammals, birds, and even people.
Trends for chlorophyll a are split into spring and summer to analyze chlorophyll a during the two seasons when phytoplankton blooms are commonly observed in different parts of Chesapeake Bay.
Long-term spring trends are mixed. Improvements are clustered in the upper tidal fresh and polyhaline/Elizabeth River regions. There are two degrading stations in the tidal fresh.
Surface Chlorophyll a: Summer
= Decreasing Chlorophyll a Concentration = Improving Water Quality
= Increasing Chlorophyll a Concentration = Degrading Water Quality
Long-term trends in summer chlorophyll a differ from spring long-term trends at some of the mesohaline and polyhaline stations. In the summer, there are degrading long-term trends in the Elizabeth River and the lower James mesohaline and polyhaline stations, while they were mostly improving in the spring. Other patterns are more similar between the seasons, including long-term improvements at upper tidal fresh stations.
Secchi Disk Depth
= Increasing Secchi Disk Depth Concentration = Improving Water Quality
= Decreasing Secchi Disk Depth Concentration = Degrading Water Quality
Secchi disk depth is a measure of visibility through the water column. This method of water quality sampling involves attaching the weighted Secchi Disk to a rope with marked intervals. The disk is lowered into the water to the point where it is no longer visible. The measurement is recorded, before raising the disk until the pattern is just visible. The average of these two measurements is the Secchi Transparency, which is a metric for determining water clarity. Watch the video below to learn more about Secchi Disk measurements.
Trends in Secchi disk depth are mixed, with half of the stations showing no trend over the long-term. Stations in the Elizabeth River show improving trends.
Bay 101: Water Clarity
Summer Bottom Dissolved Oxygen
= Increasing DO Concentration = Improving Water Quality
= Decreasing DO Concentration = Degrading Water Quality
Summer bottom dissolved oxygen trends are fairly mixed, with half of the stations showing no trend over the long-term, and the remaining stations having improving or degrading trends. A majority of improving stations are located in the South Branch of the Elizabeth River.
Bay 101: Dissolved Oxygen
Short-Term Water Quality Parameters (2012-2022)
Total Nitrogen
= Decreasing Nitrogen Concentration = Improving Water Quality
= Increasing Nitrogen Concentration = Degrading Water Quality
Over the short-term (2012-2022), TN shows mixed results with many stations showing unlikely trends. Improving trends are concentrated in the tidal fresh and oligohaline stations. All stations with degrading trends are located in mesohaline waters.
Total Phosphorus
= Decreasing Phosphorus Concentration = Improving Water Quality
= Increasing Phosphorus Concentration = Degrading Water Quality
Short-term TP trends display mixed results, but there is only one improving station. A majority of degrading trends are at tidal fresh stations, and there are more unlikely trends compared to the long-term trends for TP.
Surface Chlorophyll a: Spring
= Decreasing Chlorophyll a Concentration = Improving Water Quality
= Increasing Chlorophyll a Concentration = Degrading Water Quality
Chlorophyll a in the Spring has more stations with degrading trends in the short-term compared to the long-term in the tidal fresh stations. The majority of improvements are from stations in polyhaline/Elizabeth River area.
Surface Chlorophyll a: Summer
The spatial distribution of short-term trends in the summer is similar to those in the spring. There is one more significantly degrading trend at in the tidal fresh region in the summer compared to the spring.
Secchi Disk Depth
= Increasing Secchi Disk Depth Concentration = Improving Water Quality
= Decreasing Secchi Disk Depth Concentration = Degrading Water Quality
All stations with a likely trend show an improving trend. There are more stations with improving trends in the short-term than in the long-term.
Summer Bottom Dissolved Oxygen
= Increasing DO Concentration = Improving Water Quality
= Decreasing DO Concentration = Degrading Water Quality
Unlike the long-term trends, there are no improving short-term trends. All short-term trends show an unlikely trend except for three stations showing degrading trends.
Factors Affecting Trends
Hydrogeomorphology
- Hydro: water, including both surface and groundwater
- Geo: ground and landforms
- Morphology: the surface characteristics of landforms
Differences in the physical characteristics of a tributary can explain in part the variability in watershed nutrient yields. The figure on the right highlights linkages between water processes and landforms on nutrient loads. For example, given the lengthy time requirements for groundwater nitrogen to move through portions of the coastal plain, reductions in TN may be lagged in the long-term trend results.
Estimated Nutrient and Sediment Loads
Estimated nutrient and sediment loads to the James River are a combination of monitored loads from its U.S. Geological Survey (USGS) River Input Monitoring (RIM) station located at the nontidal-tidal interface and below-RIM simulated loads from the Chesapeake Bay Program Watershed Model. Nitrogen loads to the tidal James were primarily from the below-RIM areas, whereas phosphorus and suspended sediment loads were primarily from the RIM areas.
Estimated TN, TP, and suspended sediment (SS) loads showed an overall decline of 250 ton/yr, 31 ton/yr, and 3,700 ton/yr in the period between 1985 and 2022, respectively.
Pollutant Sources
The Chesapeake Bay Program has developed a watershed model known as the Chesapeake Assessment Scenario Tool (CAST), which helps researchers understand where sediment, nitrogen, and phosphorus come from. It is important to know the sources of nutrients polluting the Bay so that management efforts can be directed to the right place.
According to the CAST model, changes in population size, land use, and pollution management controls between 1985 and 2022 would be expected to change long-term average nitrogen, phosphorus, and sediment loads to the tidal James River by -44%, -71%, and -4%, respectively.
Changing watershed conditions and management actions between 1985 and 2022 are expected to have resulted in the agriculture, natural, stream bed and bank, and wastewater sectors achieving reductions in nitrogen, phosphorus, and sediment.
Management
Once the CAST model has identified the main sources of pollution, policy makers need to facilitate the adoption of best management practices (BMPs) to lower the amount of nutrients produced by each source sector (agricultural, urban stormwater, etc.). BMPs vary widely and their application are often measured in acres. In the graph, the acres of implemented BMPs are grouped by category at three points in time (1985, 2009, and 2022) and are compared to their Watershed Implementation Plan (WIP) target goals for 2025.
As of 2022, tillage, cover crops, pasture management, forest buffer and tree planting, stormwater management, agricultural nutrient management, and urban nutrient management were credited for 568, 314, 819, 12, 360, 1,551, and 119 square kilometers, respectively. Implementation levels for some practices are already close to achieving their planned 2025 levels: for example, 101% of planned acres for tillage had been achieved as of 2022. In contrast, about 13% of planned urban nutrient management implementation had been achieved as of 2022.
Tidal Factors
As pollution reaches the Bay, researchers look at different parts of the environment to determine the health of the Bay. Key habitat indicators like algal biomass, DO concentrations, water clarity, submerged aquatic vegetation (SAV) abundance, and fish populations are used to assess Bay health.
The diagram illustrates how hypoxia is driven by eutrophication and physical forcing while affecting sediment biogeochemistry, or the transfer of chemical elements between the environment and its organisms, and living resources.
Climate Change
The need for effective BMPs has become even more important as the effects of pollution are being amplified by climate change. As a result of the changing climate, the Chesapeake Bay watershed is experiencing an increase in precipitation, temperatures, and climatic variability, which shapes Chesapeake Bay tributary recovery trends. Climate impacts are exacerbated by local non-climate stressors (e.g., land-subsidence, land use change, growth and development). Efforts aimed to increase understanding of climate change impacts on water quality patterns can help explain lagging progress in meeting water quality standards and transform monitoring findings into actionable information.
Bay 101: Climate Change
Extreme Weather and Increased Precipitation
Extremes in rainfall - whether too much or too little - can have varying effects on the Bay ecosystem. During large rain events, river flow increases and delivers more fresh water into the Bay, decreasing the Bay’s salinity. During periods with little rainfall or extended drought, the decrease in freshwater flows results in saltier conditions, affecting habitats and aquatic species.
Mean annual precipitation for the James River from 1981 to 2020 shows a gradual increase over the period of record.
DO, water clarity, and chlorophyll a were used to estimate how the achievement of water quality goals were affected by extreme weather events. Higher attainment values mean less pollution and better water quality. Extreme weather events and major environmental policy changes are overlayed on this time series. Each color represents a different stage of trends in attainment (blue=steady improvement, purple=slight improvement, red=sharp decline, green=steady and rapid recovery). Extreme amounts of rain in 2018 and 2019 caused more water to flow through rivers and into the Bay, delivering higher amounts of pollution. While pollutant loads may be decreasing from BMP implementation efforts, increased rainfall presents a challenge as it delivers nutrients to the Bay faster, resulting in decreases in attainment observations.
Visit the link from the Mid-Atlantic Regional Integrated Sciences and Assessments (MARISA) program for more information about extreme weather events occurring in the Bay watershed:
Warming Water Temperatures
The Chesapeake Bay is shallow, with an average depth of only 6.5 meters, so changes of temperature in the atmosphere can significantly change the temperature of the water. This means that as temperatures rise in the atmosphere, water temperatures in the Bay significantly increase, as shown in the interactive map to the right. Trends from resulting marine heat waves, or prolonged anomalously warm events, indicate increases in marine heat wave frequency, duration, and cumulative yearly intensity. Warming temperatures and marine heat waves are known stressors for many of the living resources the water quality standards were developed to support. The solubility of oxygen in water decreases as temperatures increase, meaning warmer temperatures make it more difficult to attain DO criteria.
Four major mechanisms driving changes in water temperature throughout the Chesapeake Bay’s mainstream, tidal tributaries and embayments. Source: Hinson et al. 2021
Sea Level Rise
Over the past century, Bay waters have risen by about one foot, and according to a USGS study , Bay waters are predicted to rise another 1.3 to 5.2 feet over the next 100 years. This rate is higher than the global sea level rise average because the Chesapeake Bay region is also impacted by land subsidence, which is the sinking of land due to removal or displacement of water. Half of this land subsidence is estimated to be from ground water removal.
Higher water levels in the Bay can result in the loss of marshes and wetlands due to flooding. This increased flooding erodes the marsh faster than naturally occurring sand and mud can replace. When marshes face erosion, they typically move inland. Human development, however, prevents this movement of marshes and eventually the trapped marsh is eroded completely.
Wetland habitats naturally trap pollution and prevent it from entering the Bay. So, as climate change causes water levels to rise and wetland habitats are destroyed, there can be an increase of pollution seen in the Bay. Wetland restoration, therefore, can be an effective way to counter the negative effects of climate change on Bay pollution.
Use this web mapping tool to visualize community-level impacts from sea level rise.
For the Community
Beyond this study, many other conservation and watershed organizations are working towards a healthier Chesapeake Bay. One organization active in the James watershed is James River Association.
James River Association is a non-profit, member supported organization that is committed to being the guardian of the James River.
They oversee the river's conditions, swiftly address issues, advocate for policy reforms, and execute on-site projects aimed at rejuvenating the river's vitality. Through initiatives such as Watershed Restoration, James Riverkeeper, and River Advocacy, they safeguard the river's well-being. Additionally, they enhance community engagement with the river by expanding access, endorsing river-centric events, and facilitating volunteer endeavors. Furthermore, they foster connections through Environmental Education and Community Conservation programs.
Click through the interactive James River report for 2023 below provided by the James River Association.
JRA-STATE OF THE JAMES 2021
Click the link below to their website for more information about their mission and how to support their cause.
