MilesofImpariedStreams


 * Water Indicators**
 * //Fresh Water Supply//** :: Water Use
 * //Water Pollution//** :: Miles of Impaired Streams :: Riparian Buffers :: Major Dischargers :: Groundwater
 * //Case Studies//** :: Jordan Lake Rules :: Falls Lake Rules

=Miles of Impaired Waters=

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 * What is this?**

The NC Division of Water Quality assigns a primary classification to all surface waters. The classification is based on how the water is used. For example, //Class C// waters must be clean enough to support aquatic life, secondary recreation like boating or canoeing, and agriculture. //Class C// waters do not have to be clean enough for human contact (swimming) or drinking water. All surface waters must at least meet the standards of //Class C// waters (fishable/swimmable). C//lass B// waters have additional standards to meet their use for primary water contact recreation. Waters that are used as sources of water supply for drinking, culinary, or food purposes have higher levels of protection and are classed from //Water Supply (WS) I-V////,// ranging from undeveloped to highly developed watersheds. There are also supplemental classifications including //Nutrient Sensitive Waters (NSW)//. //NSW//s need additional nutrient management due to excessive growth of microscopic or macroscopic vegetation.
 * Why is this important?**

Pollution contaminates our sources of drinking water and makes water unsafe for recreation. Some pollutants can cause harmful algal blooms that reduce oxygen levels, killing fish and other wildlife. Other pollutants, such as mercury and PCBs, accumulate in the tissue of the fish we catch, making them unhealthy to eat.

When a body of water is determined to no longer meet the water quality standards for its designated use it is considered //impaired// and is placed on the 303(d) list (so named because it is mandated by Section 303(d) of the Clean Water Act). The Clean Water Act requires states to list and prioritize impaired waters and to establish //total maximum daily loads// for the pollutants causing the impairment. //Total maximum daily loads// //(TMDLs)// are an estimate of the maximum amount of a pollutant that a waterbody can assimilate in without violating water quality standards. Once total maximum daily loads are established, point sources discharging the pollutant of interest are assigned waste load allocations in their new or renewed discharge permits. In order to comply with the new permit, some facilities may have to upgrade their treatment technology. Total maximum daily loads also include recommendations of ways to reduce non-point source pollution. Water quality data that informs the decision to place a stream on the 303(d) list can be collected by: Division of Water Quality ambient monitoring system, National Pollutant Discharge Elimination System (NPDES) permittees, discharge monitoring coalitions, the Division of Water Quality biological assessment unit, North Carolina Department of Natural Resources Division of Environmental Health, and the U.S. Geologic Survey.


 * **//How do we test for water pollution?//**

Water pollution is measured using physical, chemical, and biological methods. Chemical methods can test for pH, nutrients, dissolved oxygen (DO), metals (including copper, lead, and mercury), and pesticides. Physical tests measure temperature, total suspended solids, and turbidity. Turbidity is a measure of how much the suspended materials in water decrease the clarity of water. || Volunteers collecting water quality data. photo source: [] ||

** Some examples of macroinvertebrates are insects in their larval or nymph life stage, clams, snails, worms, and crayfish. Macroinvertebrates are good indicators of stream quality because they can’t easily move away from pollution. and show effects of short and long term pollution events. Macroinvertebrates are an important part of the stream’s food web, and can show the cumulative impacts of pollution. Certain types of macroinvertebrates are more sensitive to pollution than others. If sensitive species are missing from a stream, and few species are present it is an indication that the stream is unhealthy.  Examples of macroinvertebrates (from left to right): Stonefly, Water Penny Beetle, Clam, Snail, Worm, Crayfish.
 * **//What are macroinvertebrates and what do they tell us about water pollution?//

** Photos from [] **
|| = = = What does this measure show? =

The length of impaired streams requiring total maximum daily load management in the Triangle decreased by 12% between 2008 and 2010, from 1,216 miles to 1,065 miles (Figures 1-2). For the 2010, the most common cause of impairment is turbidity, followed by copper, ecological integrity, and low dissolved oxygen (Table 1).

||
 * [[image:2008_303d_cropped.jpg width="489" height="489"]] || [[image:303dmap_2010_onlyuse.jpg width="505" height="505"]] ||
 * **Figure 1.** Impaired waters requiring a total maximum daily load management, 2008. || **Figure 2.** Impaired waters requiring a total maximum daily load management, 2010.

= = = = = = = = 
 * Table 1. ** Length of impaired streams in 2008 and 2010, listed by cause of impairment.
 * Pollutant of Interest || 2008 Length (miles) || 2010 Length (miles) ||
 * Aquatic Weeds || 34.89 || 0.00 ||
 * Chlorophyll a || 170.93 || 142.82 ||
 * Copper || 28.15 || 36.58 ||
 * Ecological/biological Integrity Benthos || 191.09 || 205.03 ||
 * Fecal Coliform (recreation) || 3.01 || 3.01 ||
 * Fish Tissue Mercury-Historical || 84.86 || 0.00 ||
 * High pH || 32.63 || 107.74 ||
 * Low Dissolved Oxygen || 88.80 || 99.99 ||
 * Low pH || 0.00 || 11.53 ||
 * NO2+NO3-N || 0.00 || 1.64 ||
 * PCB || 63.86 || 99.60 ||
 * Turbidity || 475.34 || 336.44 ||
 * Zinc || 42.75 || 21.37 ||
 * Limitations & Further Research**


 * There may be differences in assessment methodology between 2008 and 2010, so there are challenges to comparing them directly. Some of the impaired water bodies would be better measured in acres than miles. However, the files for the 303(d) list depict waters as polylines of streams and the outlines of lakes. So what is being calculated for bodies of water such as lakes is actually the length of shoreline.

The 303(d) list contains only // Category 5 // impaired waters that require a total maximum daily load. Category 4 waters are also considered impaired or threatened for one or more designated uses but do not require the development of a total maximum daily load. Category 4 three subcategories are: **


 * Category 4a: Total maximum daily load has been completed (water quality standards have not yet been achieved).
 * Category 4b: Total maximum daily load will not be attempted because other required regulatory controls (e.g., NPDES permit limits, Stormwater Program rules, buyout programs, etc.) are expected to bring the stream into compliance with water quality standards by the next regularly scheduled listing cycle.
 * Category 4c: Impairment is not caused by a pollutant. This category is intended to be used for impairments related to water control structures (i.e., dams).


 * Author:** Ginevra Ryman, Duke University :: 2010 April 23


 * Reviewers** Tom Davis Water Resources Coordinator Orange County :: Amy Pickle Duke University

Technical Notes

Where the data came from: GIS layers were downloaded from the division of water quality [] on February 10th, 2010 (2010 file) and May 5th, 2010 (2008 file). The 2010 GIS layer is currently being updated, and hopefully the new layer will be included in our results.

Link to 2008 spreadsheet: [|waa_2008.xlsx] Link to 2010 spreadsheet: [|2010_website.xlsx]

How measured: Shapefiles were first clipped using a file of the 6 county Triangle region. Then a field was added and geometry was calculated for each line segment. Length and area (miles and acres) of category 5 impaired waters.

Analyses performed: Calculated the total number of miles for each parameter of interest for the draft 2010 303(d) list using calculate geometry in ArcGIS. Water Indicators
 * //Fresh Water Supply//** :: Water Use
 * //Water Pollution//** :: Miles of Impaired Streams :: Riparian Buffers :: Major Dischargers :: Groundwater
 * //Case Studies//** :: Jordan Lake Rules :: Falls Lake Rules