National Water Quality Inventory: Report to Congress

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1 National Water Quality Inventory: Report to Congress U.S. Environmental R-16- 011 2017 EPA 841- August Protection Agency

2 Table of Contents Executive Summary ...2 Introduction ...4 Rivers and Streams ...6 Lakes, Ponds and Reservoirs ...9 Bays and Estuaries ...12 ...15 Great Lakes Wetlands ...17 References ...20 ...21 : Causes and Sources of Impairment Appendix Report to Congress 1 National Water Quality Inventory

3 National Water Quality Inventor y: Report to Congress Executive Summary This National Water Quality Inventory Report summarizes the finding s of four statistically - representative National Aquatic Resource Surveys and the site- specific assessment results reported by the states in their Integrated 305(b)/303(d) Reports submitted to the U.S. Environmental Protection Agency. sign and goals, these two sources of information complement each other and provide While different in de a valuable perspective on national water quality. National, statistically -based surveys provide water quality baselines based on consistent sampling at randomly- selected si tes across the U.S. They were developed in response to critiques about water quality monitoring and our ability to report on the condition of the nation’s waters. National Rivers and Streams Assessment 2008- 09 , 46% of Rivers and streams : According to the river and stream miles are in poor biological condition; phosphorus and nitrogen are the most widespread of the chemical stressors assessed. Lakes, ponds and reservoirs : The National Lakes Assessment 2012 finds that that 21% of the levels of nutrients, algae and est plants). Phosphorus nation’s lakes are hyp ereutrophic ( i.e., with the high and nitrogen are the most widespread stres sors in lakes. National Coastal Condition Assessment 2010 Coastal waters : According to the , 18% of the nation’s coastal and Great Lakes waters are in poor biological condition and 14% are rated poor based on a water quality index. Phosphorus is the leading stressor contributing to the poor water quality index rating. s that 32% of the nation’s wetland find National Wetland Condition Assessment 2011 Wetlands : The area is in poor biological condition, with leading stressors including surface hardening (soil compaction) and vegetation removal. -aquatic - https://www.epa.gov/national For more information on the national statistical surveys, visit . surveys resource- Report to Congress 2 National Water Quality Inventory

4 Using targeted, site- specific monitoring needed to support local management decisions, states rting at least one of their designated uses. identified a wide range of assessed waters as not fully suppo This report represents a snapshot of the state submissions as of July 2016. Mercury (primarily in fish tissue), pathogens, nutrients, PCBs, sediment, and organic • eading causes of impairment in assessed waters. enrichment/oxygen depletion were all cited as l • Leading known sources included atmospheric deposition and agricultural activities. These findings are based on data collected using a variety of sampling methods and parameters, state water quality standard s, methods of interpretation, and time periods. As states submit their Integrated Reports and EPA approves their lists of impaired waters, the information on site -specific assessments is - -load https://www.epa.gov/waterdata/assessment -and -total- maximum -daily -tracking updated online at system . -attains implementation- and- Report to Congress 3 National Water Quality Inventory

5 Introduction This National Water Quality Inventory, prepared under Section 305(b) of the Clean Water Act quality conditions in the U.S . I t draws from two complementary (CWA), presents information on water irst, it summarizes the results of st atistically -representative, types of information on water quality. F aquatic surveys conducted by the U.S. Environmental Protection Agency ( EPA ) in partnership national . Second, -specific it provides a tally of the local, site with state and tribal water quality agencies state s in the Integrated 303(d)/305(b) Reports submitted to EPA . The assessment results reported by and approaches, and each provides valuable surveys and the state assessments have different goals information that contributes to our overall picture of national water quality led for in Section 305(b) as cal of the C WA . Known as the National Aquatic Resource Surveys (NARS), t he statistical summarized in this surveys sample monitoring sites using a stratified, random report design to provide unbiased estimates of the ized condition of the broader population of waters (e.g., rivers and streams , lakes) throughout the nation. These nationally -consistent surveys, conducted on a five -year cycle, report on the extent of waters that meet the CWA goals of supporting healthy biologic al communiti es and recreation. NARS also examines the prevalence of priority physical and chemical stressors. Detailed results from these surveys are available at . https://www.epa.gov/national- aquatic -resource -surveys s provide infor to support mation states need specific monitoring and assessment Targeted, site- management decisions at watershed and local scales (e.g., whether a specific water meets its water quality uting to degradation are, etc. ) for the standards, what the sources contrib ual waters that are individ monitored. The methods states use to monitor and assess their waters -- including what they monitor, how they monitor it, and how they report their findings to EPA -- vary from state to sta te and withi n individual states over time. This reflects the differing objectives and needs of site- specific water quality issues. As states submit water quality assessment decisions, the information is loaded into the ATTAINS database -and - tracking https://www.epa.gov/waterdata/assessment -and -total- maximum -daily -load- at available -system . implementation -attains States incorporat e s tatistical survey designs into their monitoring programs as a complement to their site toring. Wh ile site -specific monitoring focuses on waters that are priorities either for -specific moni protection or restoration, state survey s provide broader context of the condition of all state waters. They serve as a cost y small representative -effective approach to assess conditions statewide using a relativel sample. The finer scale resolution of state -scale surveys help state s evaluate priorities for additional site - specific monitoring to fully characterize waters that need special protection or to develop local restoration plans. Some state surveys are integrated enhancements of the national surveys, while others focus on sessment methods. States and EPA are working on updates to a state andards or as -specific water quality st -specific assessments for a more module in ATTAINS for presenting s -scale survey results with site tate complete story on water quality . Report to Congress 4 National Water Quality Inventory

6 How do national statistical surveys and site -specific water quality assessments work together to Fundamentally present the best picture of water conditions nationwide? , the statistical survey design ensures that the data collected from a sample of waters represent the broader population of waters being his is a cost -effective means of generating national or statewide estimates to t rack changes in surveyed. T water quality. The national surveys provide consistent environmental indicators of the condition of the nation’s water resources, much as economic indicators report on the health of the nation’s economy. Their consistent sampling methods ensure that results can be aggregated into regional and national indicators of the health of the resource. The survey results quantify, with documented confidence, how widespread water quality problems are across the country and estimate the extent of waters affected by key stressors. This helps set priorities for water resource protection and restoration. Nationally -consistent surveys provide a standardized measure for tracking c hanges in the condition of the nation's wate rs over time and for evaluating progress in investments to protect and restore water quality at a broad scale. -specific monitoring efforts are an important comp lement to statistical surveys. By targeting Site cific waters that are of concern or interest to the stat e or tribe , these monitoring activities provide spe info rmation needed to support management decisions at watershed and local scales for those individual waters that are monitored. The methods states use to monitor and assess their waters vary from state to state and withi n individual states over time. Under the CWA each state or tribe may set its own water , including designated uses, narrative and numeric water quality criteria, quality standards and anti -reported assessment he state These may differ among states and tribes. Thus, t degradation policies. decisions reported in ATTAINS cannot be used to compare states and water quality conditions among tribes , identify trends in statewide or national water qua lity, or compare the impacts of specific causes or sources of impairment over time. The strength of the site -specific water quality assessment is that it supports the identification of specific wate rs provides information on localized water quality problems, , and helps the state set priorities and implement actions for restoring not meeting water quality standards these waters. This N ational Water Qualit y Inventory: Report to Congress is a brief summary of the key findings of both e in the National Aquatic Resource Surveys and the state water quality assessment reports availabl -daily maximum https://www.epa.gov/waterdata/ass -load- -and- total- essment at the ATTAINS website . The ATTAINS website contains more detailed and tracking -and -implementation -system -attains explanatory information about the state submissions; since it is updated as new reports arrive, it also contains more recent st This report represents a snapshot of the state submissions reported information. ate- as of July 2016. Report to Congress 5 National Water Quality Inventory

7 Rivers and Streams This section summarizes the findings of both the statistically -representative national rivers and streams survey and site -specific assessment results reported by the states in their Integrated 303(d)/305(b) R eports to EPA. While different in design and goals, these two sources of information complement each other and provide a valuable perspective on national water quality. 2009 Key F indings of the National Rivers and Streams Assessment 2008/ National Rivers and Streams Assessment 2008–2009: A Collaborative Survey (NRSA) presents The the results of an unprecedented sampling effort undertaken by the EPA and its state and trib al partners. It provides information on the ecological condition of the nation’s rivers and s treams and the key stressors that affect them, both on a national and an eco- regional scale. It also discusses change in water quality conditions in streams sample d for an earlier study, the Wadeable Streams Assessment of 2004. During the summers of 2008 and 2009, more than 85 field crews sampled 1,924 river and stream sites , representing 1.2 million miles of rivers and streams across the country . Using standardized field methods, they sampled waters as large as the Mississippi River and as small as mountain headwater streams. Sites -based design. This design were selected using a random sampling technique that uses a probability ensures that the results of the survey reflect the full variety of river and stream types and sizes across the U.S. To determine water quality conditions, sampling results were compared to regionally -relevant Reference condition is developed from a set of least -disturbed sites in each reference condition. ecological region and is used to select thresholds for good, fair and poor. Ratings of good, fair, and poor were applied to the findings; however, these categories have no regulatory implications. For a few indicators, such as the human healt h screening value for mercury in fish tissue, nationally -consistent . thresholds were used The goals of the NRSA are to determine the extent to which rivers and streams support healthy biological condition and recreational uses, and the extent of major st ressors that affect them. In addition, the survey supports a longer -term goal: to determine whether our rivers and streams are getting cleaner and how we might best invest in protecting and restoring them. To learn more about the NRSA, visit . aquatic -resource -surveys/nrsa https://www.epa.gov/national- uality Biological Q Biological condition i s the most comprehensive indicator of water body health: when the biology of a stream is healthy, the chemical and physical components of the stream are also typically in good condition. Twenty -eight percent of the nation’s river and stream length is in good biological condition, Report to Congress 6 National Water Quality Inventory

8 25% is in fair condition, and 46% is in onditi on (F igure 1) . These poor c based on a robust, findings are commonly- used index that combines different measures of the condition of aquatic benthic macro invertebrates (aquatic insects and oth er creatures such as crayfish). Chemical S tressors Four chemical stressors were assessed: total phosphorus, total nitrogen, salinity, and acidification. Of these, phosphorus and nitrogen are by far the most widespread. Forty -six percent of the nati on’s river and stream Figure 1 . Biological condition of the nation's rivers and streams 2008/09 NRSA ) ( Source: are rated poor because of excess miles . Poor biological levels of phosphorus and 41 levels of nitrogen excess % are rated poor because of with excess levels of in river and stream likely condition (for macroinvertebrates) is almost twice as miles phosphorus and nitrogen. tressors Physical Habitat S : excess streambed hysical habitat condition were assessed for the NRSA Four indicators of p sediments, riparian vegetative cover (vegetation in the land corridor surrounding the river or stream), ish habitat. Of these, poor riparian disturbance (human activities near the river or stream), and in -stream f riparian vegetative cover and high levels of riparian disturbance are the most widespread stressors. Twenty rcent of river and stream miles are rated poor because of poor riparian vegetative cover, -four pe However, excess levels of and 20% are rated poor because of high levels of riparian disturbance. streambed sediments, reported in 15% of river and stream length found to have a somewhat greater are about twice as likely in rivers and streams impact on biological condition. Poor biological condition is with excessive levels of streambed sediments. Human Health I ndicators Two indicators that provide insight into potential risks to human health were assessed: mercury in fish ing values for mercury in fish tissue are exceeded tissue and enterococci (bacteria). Human health screen In 23% of river and stream miles, samples (streams were not evaluated). in 13,144 miles of U.S. rivers exceed an enterococci threshold level for protecting human health. Report to Congress 7 National Water Quality Inventory

9 tate Site -Specific Assessments – Rivers and Streams Key Findings of the S States assessed 1,107,002 of the nation’s 3.5 million miles of rivers and streams. Of these assessed miles, 614,153 were identified as impaired (e.g., unable to support one or more of the uses designated for them by the state s, such as fishing or swimming). Another 487,299 assessed miles were rated good (e.g., fully support all uses ), and 5,550 were c onsidered threatened (e.g. , support their uses but exhibit a deteriorating trend ). The top causes of pollution associ ated with impairment in assessed riv ers and streams were: • Pathogens —bacteria which indicate possible fecal contamination th at may cause illness in people; detailed Updated and • Sediment, which can smother stream beds, suffocate fish eggs and bottom information on state dwelling organisms , and int erfere with drinking water treatment and assessed river and recreational uses; and is stream miles ilable from the ava • Nutrients such as phosphorus and nitrogen, which at excess levels can at ATTAINS website stimulate the growth of undesirable algae and aquatic weeds and lead to https://www.epa.gov/ . reduced levels of dissolved oxygen waterdata/assessment In many cases, states cannot always confidently identify sources of pollution - -maximum -total -and when making assessment decisions; as a result, sources are often reported as daily -load- - tracking sources of pollution, the probable Where states identified unknown or unspecified. and- implementation- most common include d: . system -attains Agric ultural activities such as crop production, grazing, and animal feeding • operations; • air) deposition, the settling of airborne pollution from many diverse sources such as Atmospheric ( factory or auto emissions; and Hydrologic modifications such as water d iversions, channelization, and dams that alter the natural • lation or distribution of water . circu It is important to note that some river and stream segments are impaired by more than one cause or source. Report to Congress 8 National Water Quality Inventory

10 Lakes, Ponds, and Reservoirs This section summari zes the findings of both the statistically -representative national lakes survey and site -specific assessment results reported by the states in their Integrated 30 3(d)/305(b) R eports to EPA. While different in design and goals, these two sources of informa tion complement each other and provide a valuable perspective on national water quality. Key Findings of the National Lakes Assessment 2012 In the summer of 2012, 1,038 lakes were sampled for the National Lakes Assessment (NLA) 2012 . This was the second lakes, ponds, and reservoirs. The statistical survey of the condition of our nation's survey results repr esent the state of nearly 112,000 natural and man- made lakes in the U.S. th at are greater than 1 hectare in area and at least one meter deep. Lakes were sampled for their water quality, biological condition, habitat condition, and recreational suitability. The goals of the NLA are to generate scientifically -valid information on the condition of the nation’s lakes, establish baseline information for trends assessment, and assist states and tribes in enhancing their lake monitoring and assessment future program. Field crews used the same methods at all lakes to ensure that results were nationally comparable. To -relevant reference sults were compared to regionally determine water quality conditions, sampling re condition. Reference condition is developed from a set of least -disturbed sites in each ecological region most and is used to select thresholds for evaluation. Ratings of least disturbed/moderately disturbed/ disturbed were applied to the findings; however, these categories have no regulatory implications. For the algal toxin indicator, analysts used thresholds developed by the World Health Organization. Trophic Condition nationally -consistent chl orophyll - a concentrations, the NLA estimated the trophic Based on logical productivity, of lakes. Twenty condition, or bio -one percent of lakes have the highest concentrations of chlorophyll a and are classified as most disturbed, or hypereutrophic; 34% are - eutrophi c; 35% are mesotrophic; and 10% have low levels of chlorophyll - a and are classified as oligotrophic. Biological Condition The NLA 2012 developed two new research indicators as indicators of biological condition: benthic The survey finds that macroinvertebrates and zooplankton. 31% of lakes have macroinvertebrate in most disturbe communities in 21% of lakes, communities of zooplankton are in most d condition; . disturbed condition Report to Congress 9 National Water Quality Inventory

11 Chemical Condition In many lakes, phosphorus is High nutrient levels are the leading problem in the natio n’s lakes. considered the limiting nutrient; small amounts can trigger rapid increases in algal growth. A bout 40% of U.S. lakes are in most disturbed condition for phosphorus, 15% are in a moderately disturbed condition, and 45 % are in least disturbed condition (Figure 2). Lakes with high levels of phosphorus are more than twice as likely to have poor conditions for benthic macroinvertebrates. While there has been no detectable change in the proportion of lakes in each condition category since 2007, additional analysis of NLA data indicates that significant increases have occurred in the concentration of phosphorus in previously low phosphorus lakes ( see Stoddard et al, 2016). (Source: NLA 2012) for phosphorus in lakes , with change from 2007 Figure 2 National condition estimates Physical Habitat Condition For the NLA, physical habitat condition was assessed based on observation of four indicators: riparian (lakeshore) vegetation cover , shallow water habitat, lake habitat complexity at the land- water interface, and lakeshore human disturbance. Healthy lakeshore habitat slows poll ution runoff and 28% provides varied and complex ecological niches for aquatic life. The 2012 survey finds that of U.S. lakes are in most disturbed condition for veget ation along the lakeshore and 29% are in most disturbed lake habitat comple condition for xity. Recreational Condition Algae and cyanobacteria are a natural part of freshwater ecosystems. However, some algae blooms, powered by high levels of nutrients and warm temperatures, can be harmful to people and animals. The NLA 2012 finds that an alga l toxin, microcystin, is detected in 39% of lakes, but concentrations reach World Health Organization levels of concern in less than 1% of lakes. For more information on the NLA, visit https://www.epa.gov/national -aquatic -resource -surveys/nla . Report to Congress 10 National Water Quality Inventory

12 Key F indings of the State Assessment s - Lakes -Specific Site es, ponds, and reservoirs of the nation’s 41.7 million acres of lak States assessed 18,513,899 t Lakes) . T he stat es identified 13,009, 273 acres as impaired (e.g., unable to support (excluding the Grea one or more of the uses designated for them by the state, such as fishing or swimming). Another all uses), assessed acres were rated good (e.g., fully support and 34,621 acres w 5,470,004 ere c onsidered threatened (e.g ., support their uses but exhibit a deteriorating trend). The top causes of pollution associated with impairment in ass essed lake acres were : • Mercury, which has been widely detected in fish tissue where it m ay pose a health r isk to people and animals who eat fish; • Nutrients such as phosphorus and nitrogen, which at excess levels can disrupt lake ecosystems by stimulating growth of undesirable a lgae and aquatic weeds and lead to reduced levels of oxygen; and that Polychlorinated b • iphenyls (PCBs), which are toxic chlorinated chemicals of industrial origin are persist . ent in fish tissue or sediments In many cases, states cannot always confidently identify sources of pollution when making assessment decisions; as a result, sourc es are often reported as unknown or unspecified. Where states identif ied probable sources , the most common included: • Atmospheric deposition from both local and long -range sources, primarily of toxic substances such as mercury, PCBs, and metals; • Agricult ural activities such as crop production, grazing , and animal feeding operations . • Natural sources such as internal nutrient recycling, drought or waterfowl. It is important to note that s ome lake acres can be impaired by more than one cause or source. lake and assessed information on state Updated and detailed reservoir acres is available from the ATTAINS website at https://www.epa.gov/waterdata/assessment -and -total- -implementation tracking -system -load- - -daily maximum -and . attains Report to Congress 11 National Water Quality Inventory

13 and the Great Lakes Bays and Estuaries Coastal Waters - -representative national coastal survey This section summarizes the findings of both the statistically the Great Lakes, coastal shoreli nes, and ocean and site -specific assessment results on bays and estuaries, eports to EPA. While reported by the states in their Integrated 303(d)/305(b) R and near coastal waters different in design and goals, these two sources of information complement each other and provide a valuable perspective on national water quality. National Coastal Condition Assessment 2010 Key Findings of the National Coastal Condition Assessment 2010 The (NCCA 2010) is the fifth in a series of reports assessing the condition of the coastal ng a vast ar ray of productiv e waters of the United States, includi 2010 addresses questions such as: estuarine, Great Lakes and coastal embayment waters. The NCCA and Great Lakes nearshore waters, and is that condition What is the condition of the nation’s coastal ent of the stressors affecting them? getting better or worse? What is the ext This report is based on an analysis of indicators of ecological condition and key stressors in the coastal waters of the Northeast Coast, Southeast Coast, Gulf Coast, Great Lakes, and West Coast regions of the contermin ous United States. In the summer of 2010, EPA and state, tribal, and federal partners monitored 1,104 sites representing 35,400 square miles of U.S. coastal and Great Lakes nearshore waters. Of this total, 405 sites representing 6,700 square miles were Gr They used the same methods at all eat Lakes nearshore or embayment waters. tionally comparable. This sites to ensure that results were na report examines four indices as indicators of a benthic index, a water quality index, a sedimen t quality U.S. coastal condition: , and an ecological index fish tissue contaminants index . Figure 3 summarizes the findings for these indices. Biological Quality Fifty -six percent of the nation’s coastal and Great Lakes nearshore waters are rated good for biological quality based on the benthic macroinvertebrate index; 10% are rated fair and 18% are rated poor. Data are incomplete or missing for 15% of waters. Within these results but specific to the Great Lakes, 20% of nearshore and embayment square miles are rated good, 12% are rated fair, and 18% are rated poor. Half of the Great Lakes area could not be assessed for various reasons, including unsuitable substrate conditions. Water Quality Water quality is rated good in 36% of coastal and Great Lakes nearshore waters, fair in 48% and poor in 14% based on the water quality index. Components of the water quality index include phosphorus, , and dissolved oxygen. The three a gen, water clarity, chlorophyll nitro indicators contributing most to the Report to Congress 12 National Water Quality Inventory

14 poor index rating are phosphorus (found at high levels and rated poor in 21% of waters), water clarity ), and chlorophyll (found at high concentrations and rated poor in 12%). (rated poor in 16% a Within these results but specific to the Great Lakes, the NCCA finds that 60% of nearshore area is rated good for water quality, 22% is rated fair, and 18% is rated poor. Water clarity contributes most to the fair and poor water quality scores for the region, and is rated poor in 31% of nearshore area. Other components of the water quality index include phosphorus, rated poor in 10% of area; dissolved oxygen, rated poor in 1% of area; and chlorophyll a , rated poor in 18% of area. Sediment Quality Overall, the rshore NCCA 2010 sediment quality index finds that 55% of coastal and Great Lakes nea waters have good sediment quality, 21% have fair quality, and 13% have poor sediment quality. Data are incomplete or missing for an additional 11% of waters . This index is based on two component indicators: sediment toxicity and sediment contaminan ts. Overall, 79% of coastal and Great Lakes waters are rated good based on low levels of sediment contaminants and 57% of waters are rated good for sediment toxicity. Within these results but specific to the Great Lakes, the sediment quality index for the nearshore coastal region shows that 51% of nearshore area is in good condition, 21% is in fair condition, and 2% is in poor condition. About a quarter of the area could not be assessed due to unsuitable substrate index is based on two component indicators: sediment toxicity and The sediment quality conditions. sediment contaminants. Overall, 56% of the Great Lakes area is rated good based on low levels of sediment contaminants and 65% is rated good for sediment toxicity. Ecological Fish Tissue Contaminants Overall, l ess than 1% of coastal and Great Lakes nearshore waters are rated good based on levels of % are rated poor, i.e., fish tissue demonstrates one contaminants in fish tissue, 26% are rated fair, and 49 or more contaminants exceeding “low effects” ecological guidelines r missing for . Data are incomplete o an additional 24% of waters. It is important to note that fish tissue contamination findings are based on ecological guidelines designed to evaluate whether concentrations of contaminants in fish tiss ue pose a potential risk to fish and wildlife. Fish contaminant levels were not compared to human health thresholds because this survey analyzed the whole fish, not the fillet portion generally consumed by humans. er fish, birds, and he most sensitive freshwa Screening values are based on impacts to t ter or saltwat wildlife species. Within these results but specific to the Great Lakes, l ess than 1% of nearshore area is rated good based on levels of contaminants in fish tissue, 20% is rated fair, and 38% is rated poor, i.e., fish tissue demonstrates one or more contaminants exceeding “low effects” ecological guidelines. Data are . incomplete or missing for an additional 42% of area Report to Congress 13 National Water Quality Inventory

15 at https://www.epa.gov/national -aquatic -resource - NCCA 2010 is available More information on the surveys/ncca . es (Source: NCCA 2010). anking for all indic r 3 . Percentage of coastal area achieving each condition Figure Assessments Key Findings of the State Site -Specific – Coastal Waters Bays and Estuaries States assessed 35,094 ’s total 87,791 square miles of bays and estuaries. (N ote that of the nation by Great Lakes, coastal shoreline miles, and ocean and near coastal square miles were assessed separately impaired (e.g ). The states identified 27,483 square miles as , and are reported below the states ., unable to support one or more of the uses designated for them by the state, such as fishing or swimming). Another ., fully support 7,611 square miles were rated good ( all uses). e.g nd estuar ine square miles The top causes of pollution associated with impairment in assessed bay a : were Mercury, most common in fish tissue ; • r produced in the U.S., persist in sediments and • PCBs, toxic chemicals which, though no longe ned hazardous wast fish tissue and may be released via spills, leaks, and from poorly maintai e sites or the incin eration of some wastes; and Pathogens, bacteria which indicate possible fecal contamination that may cause illness in people. • Report to Congress 14 National Water Quality Inventory

16 Since states cannot always confidently identify sources of pollution when making assessment sources as unknown or unspecified. Where they identif ied probable sources, ften report decisions, they o the most common included : Atmosphe ric deposition, which can transport airborne pollutants such as mercury and PCBs from • industrial and urban centers; and • Municipal di scharges/sewage, which includes sewage treatment plants, septic systems, and wet weather sewer overflows. • Other sources, such as those outside the state’s boundaries or jurisdiction. It should be noted that some bay or estuary square miles can be impaired by more than one cause or source. Great Lakes Shoreline and Open Waters States assessed 4,431 of the nation’s 5,000 miles of Great Lakes shoreline miles. Of these assessed miles, 4,353 were reported as impaired for one or more designated use. The leading causes of imp airment s of impairment were atmospheric included PCBs, dioxins, and pesticides. The leadi ng probable source deposition, legacy/historical pollution – primarily contaminated sediment – and agriculture. of 60,500 tota Great Lakes open l U.S. square miles of States also as waters. Of these, all sessed 53,332 square miles were reported as impaired for one or more designated use. PCBs, dioxins, and but 62 sources including mercury were identified as leading causes of impairment, with leading probable related runoff/stormwater. atmospheric deposition, legacy/historical pollution, and urban- assessed Updated and detailed state information on Coastal and Great Lakes waters is available from the at ATTAINS website -total- -and https://www.epa.gov/waterdata/assessment - -implementation -and tracking -daily -load- maximum . system - attains Report to Congress 15 National Water Quality Inventory

17 Wetlands -representative national wetlands survey This section summarizes the findings of both the statistically and site -specific assessment results on wetlands reported by the states in their Integrated 303(d)/305(b) Reports to EPA. While different in design and goals, these two sources of information complement each other and provide a valuable perspective on national water quality. Key Findings of t he National Wetland Condition Assessment 2011 The National Wetland Condition Assessment 2011 (NWCA) is the first national evaluation of the ecologic all wetlands, from the tidal and non- tidal wetlands al condition of U.S. wetlands. It encompasses along our coasts to the forested swamps, prairie potholes and meadows of the interior plains. The NWCA uses a statistical survey design to e xamine the chemical, physical and biological integrity of wet lands -accepted indicat through a set of commonly- used and widely ors, and begins to address some of the gaps in our unde rstanding of wetland health. During the spring and summer of 2011, more than 50 field crews sampled 1,179 wetland sites across ion, soils, hydrology, algae, the country. Each crew used standardized field protocols to sample vegetat water chemistry, and potential stressors at each site. Most sites were selected using a random sampling technique that ensures that the results of the survey reflect the range of wetlands in the target population across the U. S. Data collected at these randomly selected sites are used to produce national and regional estimates of wetland condition. Condition Biological Plant presence, abundance and trait information – e.g., invasive or native status, tolerance to disturbance – are used t o assess biological condition. Vegetation is a particularly good indicator of wetland condition because of its ability to integrate different wetland processes and because plants ple temporal and spatial scales. Using respond to physical, chemical, and biological disturbances at multi field -collected data and plant trait information, a national Vegetation Multimetric Index (VMMI) was developed. The NWCA finds that 48% of wetland area nationally has healthy plant communities and is in good conditi on, 20% is in fair condition and 32% is in poor condition (Figure 4). Poor biological condition can adversely affect fish and wildlife species, reduce recreational opportunities, and lead to diminished water quality and flood retention benefits. Of the fo -based units reported on by NWCA, the West has the lowest percentage ur major ecoregion (21%). The Coastal Plains, Eastern Mountains and Upper Midwest, and of wetland area in good condition condition. Interior Plains have a range of 44% to 52% of wetland area in good Report to Congress 16 National Water Quality Inventory

18 Figure 4 . Estimated extent of wetland biological condition by condition classes ). Results are (Source: NWCA 2011 (good, fair, poor) based on the VMMI. reported for the nation and by NWCA Aggregated Ecoregion. Physical Disturbance Nationally, 27% of wetland area has high occurences of activities related to surface hardening ( e.g., soil compaction, roads). These activities affect how water flows in and out of wetlands and the amount of water that enters and stays within wetlands, potentially affecting plant productivity, nutrient cycling, and l physical habitat. overal has high occurrences of activities related to An equal percentage of wetland area nationally (27%) moval or loss of vegetation due to activities such as grazing, mowing, and forest removal. Re vegetation clearing may increase sediment, nutrient, and pollutant loads entering and staying in a wetland. high occurrences of d one quarter of wetland area nationally (23%) has Nearly itching. Ditching affects how water flows in and out of wetlands, potentially affecting plant productivity, nutrient -cycling, and physical habitat. undant in 19% of wetland area. Nonnative plants replace native plants, Nonnative plants are ab resulting in loss of biodiversity and habitat for fish and wildlife species. Chemical Indicators assessed for NWCA usi ng soil data : Heavy Metal Index and Two c hemical indicators of stress were soil phosphorus concentration. Stressor levels for both of these indicato rs are low for the majority of wetland area nationally. However, stressor levels for the Heavy Metal Index are moderate for 47% of wetland area in the West and 31% of wetland area in the Eastern Mountains and Upper Midwest. Stressor rus are high for 13% of wetland area in the Eastern Mountains and Upper Midwest. levels for soil phospho Report to Congress 17 National Water Quality Inventory

19 NWCA conducted the first national study of algal toxins in wetlands. Microcystin, a chemical toxin people, pets, and wildlife, is detected in 12% of wetland are a nationally. However, based on that can harm recreational exposure risk levels established by the World Health Organization, very little wetland area (<1%) poses either moderate or high risk levels. Key Findings of the State Site -Specific Assessments – Wetland s States assessed 1,232,559 of the nation’s estimated 107,700,000 wetland acres. Of these , 657,653 or at least one designated use and 574,907 acres acres were reported as impaired f were reported in good condition (i.e., fully support all of the uses designated by the states). ed wetland acres were: The top causes of impairment in assess • Organic enrichment/oxygen depletion, occurring when high levels of organic materials use up oxygen when they degrade; • Mercury, a toxic metal most commonly found in fish tissue; an d Metals other than mercury, such as arsenic and selenium. • Updated and detailed on nformation state i Since states cannot always confidently identify sources of pollution when assessed wetland nown or unspecified. making assessment decisions, they often report sources as unk acres is available : Where states identified probable sourc es, the most common included from the ATTAINS database at • Agricultural activities such as crop production, grazing , and animal feeding https://www.epa.gov/ operations; and waterdata/assessment -total -and -maximum - Atmosphe • ric deposition, the settling of airborne pollution from many daily tracking -load- - diverse sources (both near and far) such a s factory or auto em issions. and- implementation- • Industr y, primarily petroleum and natural gas production activities. . system -attains the same wetland segments can be impaired by more It should be noted that than one cause or source. National Water Quality Inventory Report to Congress 18

20 References ulsen, D. V. Peck, R. Mitchell, and A. Stoddard, J. L., J. Van Sickle, A. T. Herlihy, J. Brahney, S. Pa I. Pollard. 2016. Continental -Scale Increase in Lake and Stream Phosphorus: Are Oligotrophic Systems Disappearing in the United States? 50:3409 -3415. Environmental Science & Technology U.S. Environmental Protection Ag ency. Office of Water and Office of Research and Development. -006). Washington, DC. December National Coastal Condition Assessment 2010 (EPA 841 -R-15 2015. http://www.epa.gov/nationa l-aquatic -resource- surveys/ncca U.S. Environmental Protection Agency. Office of Water and Office of Research and Development. 841 -R-16 National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States . (EPA - https://nationallakesassessment.epa.gov/ r 2016. . Decembe 113) . Washington, DC U.S. Environmental Protection Agency. Office of Water and Office of Research and Development. National Rivers and Streams Assessment 2008 -2009: A C ollaborative Survey (EPA 841- R-16/007). Washington, DC. March 2016. http://www.epa.gov/national ‐ aquatic ‐ resource ‐ surveys/nrsa U.S. Environmental Protection Agency. Office of Water and Office of Research and A Collaborative Survey o Development. : f the Nation’s National Wetland Condition Assessment 2011 - -aquatic https://www.epa.gov/national -R-15 Wetlands (EPA 843 -005) . Washington, DC. May 2016. resource- surveys/nwca Report to Congress 19 National Water Quality Inventory

21 Appendix: Causes and Sources of Impairme nt States, tribes and other jurisdictions monitor for a variety of pollutants, or causes of impairment. Table 1 provides a list of major causes of impairment cited in this report. Table 1. Major Impairment Cause Categories Used in this Report Categor y Examples Cause Unknown – Impaired Biota Impairment or degradation of the biological community (e.g. fish, macroinvertebrates) due to unknown/unidentified cause Dioxins Highly toxic, carcinogenic petroleum -derived chemicals that are persistent in the environment and may be found in fish tissue, water column, or sediments. Fish Consumption Advisory Contaminated fish tissue (contaminant unspecified) Flow Alterations Changes in stream flow due to human activity; includes water diversions for purposes such as irrigation. Habitat Alterations Modifications to substrate, streambanks, fish habitat; barriers. Metals Substances identified only as “metals,” such as selenium, lead, copper, arsenic, manganese, others. (NOTE: may, in some include mercury) Mercury A toxic metal with neurological and developmental impacts found in fish tissue, water column, or sediments. Nuisance Exotic Species -native fish, animals, or plants such as Eurasian milfoil, Hydrilla, or zebra mussels Non which choke out native species and alter the ecological balance of waters. Primarily nitrogen and phosphorus; in excess amounts, nutrients over -stimulate the growth Nutrients of weeds and algae and can lead to oxygen depletion. Organic Enrichment/Oxygen Low levels of dissolved oxygen; high levels of biochemical oxygen demanding substances Depletion (organic materials such as plant matter, food processing waste, and sewage) that use up dissolved oxygen in water when they degrade. Pathogens Bacteria and pathogen indicators, E. coli, Entero cocci, total coliforms, fecal coliforms, used as indicators of possible contamination by sewage, livestock runoff, and septic tanks. Polychlorinated A toxic mixture of chlorinated chemicals that are no longer used but are persistent in the Biphenyls (PCBs) environment; used originally in industry and electrical equipment), primarily found in fish tissue or sediments. Pesticides Substances identified only as “pesticides;” also, chlordane, atrazine, carbofuran, and others. Many older pesticides are persistent in the environment. Excess sediments, siltation; affects aquatic communities by altering and suffocating habitat Sediment and clogging fish gills. Toxic Organics Chemicals identified only as “toxic organics;” also, priority organic compounds, non- prio rity organic compounds, polycyclic aromatic hydrocarbons (PAH), others; often persistent in the environment. Report to Congress 20 National Water Quality Inventory

22 Where possible, the states, tribes and other jurisdictions identify the sources of those pollutants discharge directly into surface waters from a airment. Point sources associated with water quality imp conveyance such as a pipe; nonpoint sources deliver pollutants from diffuse origins, such as fields and streets. Table 2 identifies the source categories cited in this report. 2. Major Pollutant Source Categories Used in this Report Table Examples Category Agriculture Crop production, feedlots (including concentrated animal feeding operations), grazing, manure runoff Atmospheric Deposition Airborne pollution from many diverse sourc es (such as factory and automobile emissions and pesticide applications) that settles to land or water Construction Residential development, bridge and road construction, land development Habitat Alterations (not directly Riparian and in- stream habitat modification and loss, filling and draining of wetlands, related to hydromodification) removal of riparian vegetation, streambank erosion Hydromodification Pond construction, channelization, dam construction, dredging, flow alterations from water diversions, flow regulation, hydropower generation, stream bank destabilization and modification, upstream impoundments Industrial Factories, industrial and commercial areas, cooling water intake structures, mill tailings storage piles, land application of biosolids, land disposal, landfills, leaking Land Application/Waste Salt Sites/Tanks underground storage tanks Brownfield sites, contaminated sediments, in- Legacy/Historical Pollutants place contaminants Septic systems, sewage treatment plants, domestic sewage lagoons, sanitary sewer Municipal Discharges/Sewage overflows, municipal dry and wet weather discharges, unpermitted discharges of domestic wastes, combined sewer overflows, septage disposal -related impacts, waterfowl Natural/Wildlife Flooding, drought Recreation and Tourism Golf courses, marinas, turf management, boat maintenance Resource Extraction Abandoned mining, acid mine drainage, coal mining, dredge mining, mountaintop mining, petroleum/natural gas activities, surface mining Forest management, forest fire suppression, forest roads, reforestation, woodlot site Silviculture (Fore stry) clearance Spills/Dumping Accidental releases/spills, pipeline breaks Unknown Source of impairment is unknown Unspecified Nonpoint Source identified as nonpoint, but no further information available Source of impairment is Urban- related Runoff/Storm Water Discharges from municipal separate storm sewers (MS4), parking lot and impervious surfaces runoff, highway and road runoff, storm sewers, urban runoff, permitted stormwater discharges Report to Congress 21 National Water Quality Inventory

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