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Concerns about water quality in the South have engendered proactive research, monitoring, and control programs. In addition, public and private stakeholders are supporting the development of comprehensive watershed assessments and related studies. The goal of these programs and studies is to assess and improve water quality in the United States, including the South. Two primary programs that have been developed to report information on the current status of water quality: (1) National Water Quality Inventories, and (2) USEPA Index of Watershed Indicators (IWI) Program. The National Water Quality Inventories provide information at the regional and State level, and the IWI Program provides information about water quality in individual watersheds (USGS 8-digit HUC). These and other regional assessment programs such as the USGS National Water Quality Assessment Program and Southern Appalachian Assessment are summarized in this section.
To assess progress toward the goals of the CWA, States, Tribes, and other jurisdictions adopt water-quality standards, which must be approved by the USEPA. Water-quality standards have three elements, which are described below (U.S. Environmental Protection Agency 2000a):
1. Designated Uses: All waters of the United States are required by law to be designated for "beneficial uses." Examples include drinking water supply, contact recreation (swimming), and support of warm-and cold-water fisheries. States are responsible for assigning designations and can designate multiple uses for the same waterbody.
2. Criteria: Scientists establish criteria necessary to protect the designated uses. Criteria can include chemical-specific thresholds that protect fish and humans from adverse health effects as well as biological and habitat conditions.
3. Antidegradation policy: The antidegradation policy is intended to prevent waters from deteriorating from their current conditions. Therefore, States cannot change a waterbody's designated use(s) to lower water-quality standards without extensive justification
The status of the Nation's waters is determined by assessing the degree to which the States' water-quality standards are met (U.S. Environmental Protection Agency 1994). States, Tribes, and other jurisdictions are required and/or encouraged, under Section 305(b) of the CWA, to submit a report to the USEPA on the status of their waterbodies. For purposes of this section, discussion is limited to State 305(b) reports and does not include reports from tribes or other jurisdictions. States are required to submit updated 305(b) reports once every 2 years. According to Section 305(b) of the CWA, reports should include the following:
· A description of water quality for all navigable waters in the State.
· An analysis of the extent to which all navigable waters in the State provide for the protection and propagation of shellfish, fish, and wildlife, and allow recreational activities in and on the water.
· An analysis of the extent to which the elimination of the pollutants has been or will be achieved to meet water-quality standards.
· Recommendations of actions needed to achieve the water-quality standard.
· An estimate of the extent of environmental impact and the economic and social costs and benefits associated with achieving the water-quality standard, and the date by which the water-quality standard will be achieved.
· A description of the nature and extent of nonpoint sources of pollutants and recommendations of programs to control these sources, including costs to implement such controls.
The CWA requires States to assess the degree to which waters meet adopted water-quality standards. In order to meet this requirement, States examine two types of data: monitored data and evaluated data. Monitored data supply quantitative information including field measurements that are not more than 5 years old, such as biological, habitat, toxicity, and/or physical/chemical conditions in waterbodies, sediments, and fish tissues. Evaluated data are quantitative and/or qualitative information frequently used to fill data gaps. Evaluated data include field measurements that are more than 5 years old, estimates generated using land use and source information, predictive models, and surveys of fish and game biologists (U.S Environmental Protection Agency 2000a). An example of this process follows: The degree to which the Georgia Water Quality standard for streams classified as "fishable" must be assessed. The standard is that "fishable" streams must contain less than 1,000 fecal coliform bacteria per 100 ml of water for the months of November through April (Georgia Water Quality Control Act 391-3-6.03). If monitored or evaluated data indicate that fecal coliform exceeds this standard, the fishable use criterion is not supported.
Depending on the degree to which designated uses are supported, States place assessed waters into the following categories (U.S. Environmental Protection Agency 2000a):
1. Fully Supporting Overall Use: A waterbody that meets all of the established criteria for designated beneficial uses.
2. Threatened Overall Use: A waterbody that fully supports all of its designated beneficial uses but is in danger of not fully supporting one or more of the uses.
3. Partially Supporting Overall Use: A waterbody that does not meet all of the established criteria for one or more of its designated beneficial uses.
4. Not Supporting Overall Use: A waterbody that does not meet any of the established criteria for one or more of its designated beneficial uses.
5. Not Attainable: A waterbody for which one or more designated beneficial uses is not achievable due to natural conditions or human activity that cannot be reversed without imposing widespread economic and social impacts. This category is derived by a State-conducted use-attainability study.
Impaired waters are defined as any waterbody that is classified as partially supporting or not supporting overall use. Impaired waterbodies are summed, and the State reports the amount of "Total Impaired" waters.
The USEPA compiles the information in State 305(b) reports and submits a summary report entitled "National Water Quality Inventory Report to Congress." These reports are the principal vehicle for informing Congress and the public about general water-quality conditions in the United States. Discussions and data for this Chapter are based on the information included in the National Water Quality Inventory Reports to Congress (National 305(b) Reports).
The National 305(b) Reports from 1988 to 1998 were evaluated to identify recent trends in water quality in the South (U.S. Environmental Protection Agency 1990, 1992, 1994, 1996, 1998a, 2000a). These reports include summaries of water quality for rivers and streams, lakes, reservoirs, ponds, tidal estuaries, shoreline waters, coral reefs, wetlands, and groundwater in individual States. In this Chapter, only water quality of rivers and streams in the South is reported. The National 305(b) Reports do not describe the health of all rivers and streams in the South because the States have not comprehensively assessed all their waters. Due to funding and monitoring constraints, States only assess a subset of total waters. Therefore, the health of only those portions of rivers and streams assessed and reported in individual-State water-quality inventories are summarized in this Chapter.
Southern States assessed a total of approximately 149,260 river miles in 1988 and approximately 231,600 river miles in 1998 (U.S. Environmental Protection Agency 1990, U.S. Environmental Protection Agency 2000a). The term "river miles" is used interchangeably with "river and stream miles" in this Chapter. Assessed river miles increased by 55 percent over this 10-year period. The 231,600 assessed river miles in 1998 represent approximately 25 percent of the South's total river and stream miles, which is consistent with the percent assessed nationwide in 1998. This amount is considerable because only approximately 470,000 river miles in the South are perennial waters (flow year-round). The remaining 463,000 river miles are intermittent or ephemeral, which means they are dry for some or most of the year.
As described previously, each State reports the assessed river miles as fully supporting, partially supporting, or not supporting overall use. The last two categories represent impaired river miles. From 1988 to 1998, 9 of the 13 Southern States reported an increase in impaired river miles. The percentage of river miles that were impaired rose from 26 to 45 during the 10-year period. In 1998, Southern States reported that 55 percent of the 231,600 assessed river miles fully support all of their uses. This percentage is slightly lower than the nationwide percentage in 1998 (65 percent). Of the fully supporting river miles, 10 percent (approximately 23,700 river miles) were considered threatened. These threatened waters may need special attention and additional monitoring to prevent further deterioration. Some form of pollution or habitat degradation impairs the remaining 45 percent (103,441 river miles) of the assessed river miles.
The designation of river miles as being impaired is a complicated process that varies among reporting cycles and States. In many cases, States do not use directly comparable criteria and monitoring strategies to measure their water quality. Therefore, States with strict criteria for defining healthy waters are more likely to report that a high percentage of their waters are not fully supporting designated uses. Similarly, States with comprehensive monitoring programs are more likely to identify more water-quality problems. Because of these issues, it is likely that the increase in impaired miles from 1988 to 1998 is related to the overall increase in assessed river miles. As a result, one cannot assume that water quality is worse now than in 1988 just because an individual State reports a higher number or percentage of impaired waters. A more thorough discussion of the data limitations of the 305(b) reports is included in Section 5.2.1.4.
Each State identifies causes and sources of impairment of rivers and streams in order to determine where improvements are needed, and to assess the effectiveness of current water-quality programs and protection policies. Causes of impairment are pollutants, practices, or processes that result in numeric or narrative support criteria being exceeded. Specific causes of impairment may include chemical contaminants (such as polychlorinated biphenyls, dioxin, and metals), physical conditions (such as temperature), and biological conditions (such as aquatic weeds) (U.S. Environmental Protection Agency 1998a). A waterbody may be affected by multiple causes. Descriptions of the common causes of pollution included in the National 305(b) Reports are provided in Table 1. The leading causes of pollution in southern rivers and streams from 1988 to 1998 were siltation (sedimentation), pathogens (bacteria), nutrients, and organic enrichment.
Once the cause of impairment is identified, the States report the estimated source of the impairment. There are two broad categories of sources of pollution: (1) point-source pollution and (2) nonpoint-source pollution. The fundamental difference between these two categories is the manner in which the pollutant reaches the waterbody, which is often directly related to land use. The current statutory definition of a point source is as follows (Water Quality Act, Sec. 502-514, U.S. Congress, 1987):
The term "point source" means any discernible, confined, and discrete conveyance, including, but not limited to any pipe, ditch, channel, tunnel, conduit, well discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or floating craft, from which pollutants are or may be discharged. This term does not include agricultural storm water discharges and return flows from irrigated agriculture.
Research conducted in the late 1970's indicated that over half of all water pollution was due to nonpoint sources (Neary and others 1989). Therefore, the CWA was amended in 1987 to place more emphasis on proactive approaches for controlling nonpoint-source pollution (Novotny and Olem 1994). Nonpoint-source pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, or seepage. Descriptions of the common point and nonpoint sources of pollution identified in the National 305(b) Reports are provided in Table 2. As is the case with causes of impairment, a river mile or waterbody may be affected by multiple sources.
A source of pollution is often the land-use practice that generates a reported cause of impairment; therefore, causes and sources of impairment are inter-linked. One particular cause may originate from multiple sources. For example, sedimentation can originate from agricultural practices, urban stormwater runoff, and/or road construction sites. Similarly, one particular source may generate multiple causes or pollutants. For example, silvicultural practices can generate sedimentation, nutrient loading, and pesticide inputs. The interconnection between causes and sources is summarized in Table 3.
The leading point and nonpoint sources of impairment for rivers and streams in the South from 1988 to 1998 are depicted in Figure 1. The relative contributions of point and nonpoint sources of pollution in rivers and streams in each of the Southern States are shown in Figure 2. During this time, nonpoint sources contributed annually almost 70 percent of the total pollution to impaired rivers and streams. In the South, as well as nationwide, agricultural activities, such as crop production and animal operations, were the most widespread sources of pollution in assessed rivers and streams. Agriculture accounted for almost half of the total pollution, greater than all point-source discharges combined. After agriculture, the States reported that municipal treatment plants, storm sewers/urban runoff, and hydrologic/habitat modification were the most common sources of impairment during this 10-year timeframe. Silviculture ranked 10th out of the 11 major sources of impairment during this time. Each of the leading sources of impairment is grouped into major land-use practices, and the impacts of these practices are discussed in Section 5.3.
The leading sources of impairment for rivers and streams in individual Southern States from 1988 to 1998 are shown in Figure 3 and reported in Table 4. With the exception of Georgia and Texas, agricultural activities were the leading sources of pollution in each State during this time. Storm sewer discharges and urban runoff were the largest sources of pollutants in Georgia, and municipal discharges were the largest source of pollutants in Texas. The designation of river miles as being impaired by a specific source is a complicated process that varies among reporting cycles and States. Data limitations of the 305(b) reports are discussed more thoroughly in the following section.
The National 305(b) Reports provide snapshots of water quality, as assessed by individual States. The reports are not recommended for determining statistically significant trends concerning our Nation's water resources (U.S. Environmental Protection Agency 1992). Some other limitations on use of these reports that have been identified include:
· Inconsistent data reporting over time (Society of American Foresters 2000).
· Variability between States regarding the compilation of reports (U.S. Environmental Protection Agency 1994, Society of American Foresters 2000).
· Insufficient water-quality data to make accurate designations in assessed waters (Society of American Foresters 2000).
· Conditions in assessed waters cannot always be extrapolated to estimate conditions in nonassessed waters; information provided by States generally reflects monitoring and evaluation efforts that have been focused within problem areas of individual waters (U.S. Environmental Protection Agency 1994).
· In some instances in the past, impaired waters were overestimated by States to qualify for greater Federal funding to address potential impairment problems, as opposed to actual impairments (Society of American Foresters 2000).
Based on these limitations, reliance on data from these reports for statistical numeric trends over time or for specific comparisons between States is not recommended. However, despite these limitations, this information represents the most comprehensive set of current water-quality data available for the South. These reports were used in this Chapter to identify general trends over time and the major causes and sources of impairment to rivers and streams in the South. For each individual State, the most significant information from Figure 3 and Table 4 is the relative contribution of each source.
The USEPA introduced the IWI program in October 1997 to increase public awareness about the health of the Nation's watersheds. The primary objectives of the IWI program are to:
· Develop a consistent, descriptive technique for characterizing the condition and vulnerability of individual watersheds across the Nation.
· Make this information available in a way that informs and inspires Americans to learn more about their water resources, what affects those resources, and how to protect and restore them.
· Help water-quality-management professionals make better decisions on strategies and priorities for environmental programs.
· Establish a national baseline on the condition and vulnerability of aquatic resources that could be used over time to help measure progress toward the goal that all watersheds be healthy and productive.
In order to achieve these objectives, 15 individual indicators of condition and vulnerability of aquatic systems in each of the 2,262 watersheds in the 50 States and Puerto Rico were developed and used to rank each watershed (U.S. Environmental Protection Agency 2001c). These 15 indicators are listed and discussed in The Index of Watershed Indicators (U.S. Environmental Protection Agency 1997). Watersheds are delineated using the USGS 8-digit HUC classification system, as described in Section 4.1. Federal and State agencies, stakeholders, and other organizations contribute to the information gathered for the IWI. After making an assessment of condition, vulnerability, and data sufficiency, the condition of the watershed is scored and assigned one of the following general categories: (1) better water quality, (2) water quality with less serious problems, (3) water quality with more serious problems, and (4) insufficient data (U.S. Environmental Protection Agency 2001c).
The most recent IWI information (September 1999) was compiled to provide a current characterization of water quality in individual watersheds in the South. Figure 4 provides a graphic representation of this information. Table 5 summarizes this information at the State-level. Based on these data, 188 individual watersheds (USGS 8-digit HUCS) are characterized as having relatively good water quality, which represent 30 percent of the land area in the South. Two hundred and forty one individual watersheds (36 percent of the land area) are characterized as having moderate water-quality problems, and 115 individual watersheds (15 percent of the land area) are classified as having more serious water-quality problems. One hundred twenty eight individual watersheds (19 percent of the land area) do not have enough information to provide an overall characterization (Figure 4).
The majority of more serious water-quality problems are located in Louisiana, Mississippi, South Carolina, and Oklahoma. Watersheds characterized by less serious water-quality problems are scattered throughout the region, with concentrations in Georgia, South Carolina, and southern Florida. States with higher percentages of better water quality include Virginia, North Carolina, Alabama, and Arkansas. Significant areas of Texas, particularly watersheds in the western portion of the State, do not have enough information to provide an adequate characterization of water quality (Table 5).
Table 6 presents the same information as Table 5, except the IWI information is aggregated by ecological province. A complete description of the ecological provinces in the South is included in Chapter HLTH-1. The best water quality is generally found in the Central Appalachian Broadleaf Forest and the Ozark Broadleaf Forest. Ecological provinces with more serious water-quality problems include the Lower Mississippi Riverine Forest and the Outer Coastal Plain Mixed Forest.
Through the "Surf Your Watershed" Internet feature on the USEPA web page (U.S. Environmental Protection Agency 2001a), the public can access information about a watershed of interest as well as view the IWI data for that watershed. IWI represents a focused, long-term reporting tool that may assist in pinpointing specific problems in a watershed, and in providing improved assessment of current watershed conditions and future trends (U.S. Environmental Protection Agency 2001c).
USGS established the NAWQA program in 1991 to assess and provide past, present, and future water-quality conditions in 60 river basins and aquifers nationwide. The NAWQA program is a long-term comparative study of the relationship between human impact and natural factors and the resulting water quality condition within an area. NAWQA studies focus on region-specific factors that affect aquatic habitat.
The assessed areas, referred to as "study units," account for 60 to 70 percent of the Nation's water use, and cover about one-half of the land area of the United States (U.S. Geological Survey 2001b). Assessments were initiated in 20 study units in 1991, 20 in 1993, and 20 in 1997, and data were collected by Federal, State, and local agencies, as well as universities and environmental groups. The 16 NAWQA study units for the South are presented in Table 7. Due to the number of individual basin reports, specific findings for each study unit are not summarized in this report; however, some key findings from several of the basin studies are discussed in individual sections below as they relate to the effects of various land uses on water quality. Additional information on each of the southern study units, including specific reports and key study findings, can be accessed via the USGS Internet site at: http://water.usgs.gov/nawqa/nawqamap.html
.A recent study conducted in the Southern Appalachians indicates that overall water quality has improved slightly since passage of the CWA (Southern Appalachian Man and the Biosphere 1996). The Southern Appalachians include an area of approximately 37.4 million acres of mountains, foothills, and valleys stretching from northern Virginia and eastern West Virginia to northwestern South Carolina, northern Georgia, and northern Alabama. Other key findings included in this study were:
· Population growth and landscape alterations have resulted in water-quality degradation.
· The Tennessee River and Alabama River Basins are the most significantly impacted watersheds in the Southern Appalachians.
· Acidity of some streams in the area is increasing.
· Mining, urbanization, and dams have the largest effects on regional hydrology.
· Two-thirds of the reported localized water-quality impacts were a result of nonpoint-source pollution, including agricultural runoff, stormwater discharge, and landfill and mining leachate.
· Mining impacts on water quality occur in the Tennessee River Basin and southwestern Virginia.
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content: Benjamin E. West |
created: 21-NOV-2001 |