hydrologic units in Virginia
Source: Virginia Department of Conservation and Recreation, Hydrologic Unit Geography
The Clean Water Act is a Federal law, passed by the US Congress and enforced by Federal judges as well as the Environmental Protection Agency (EPA). Detailed Federal water quality standards were established by EPA, and the Federal agency then delegated primary responsibility for enforcement of those water quality standards to the states.
When humans use water, we alter its qualities by adding chemicals, nutrients, salts, etc. DEQ monitors for over 130 pollutants. Temperature is also a factor; cooling water coming into a natural stream from a power plant is typically warmer than natural. Wastewater treatment plants process the water, but do not clean up 100% of all the pollutants.
DEQ issues permits to allow wastewater, at a defined minimum level of quality, to go into creeks at defined locations such as the outlet pipe coming from a school or factory. In the jargon of pollution control, these "point sources" of pollution are managed through pollution limits defined in individual National Pollution Discharge Elimination System (NPDES) permits established under Section 402 of the Clean Water Act.
Lawsuits, particularly one in 1998 by the American Littoral Society and the American Canoe Association, forced Virginia to accelerate the assessment of water quality, to see which waterbodies are clean enough to meet the uses defined for it. EPA must approve the water assessments completed by the state, plus clean-up plans known as Total Maximum Daily Load (TMDL) plans.
TMDL's developed by DEQ define how much pollution can be absorbed each day by a particular waterbody (creek, lake, or estuary such as the Chesapeake Bay). Since the 1998 consent decree, all TMDL's were scheduled for completion within 12 years after impairment is identified - but the EPA's 2009 mandate for Virginia and Maryland to complete a Chesapeake Bay TMDL defined a completion date of December, 2010. When the states missed that deadline, EPA completed the TMDL itself.
Virginia DEQ has assessed streams, lakes, and estuaries in nearly all of its 1,247 separate hydrologic units or subwatersheds. Eaxch of the 1,247 separate hydrologic units is identified by a 12-digit hydrologic unit code in the National Watershed Boundary Dataset, and averages between 10-40,000 acres.2 DEQ determined if each water body (section of a stream, lake, or estuary) met standards for at least one designated use.
Most were assessed in 2008, as identified in the Final 2008 305(b)/303(d) Water Quality Assessment Integrated Report to the Federal Environmental Protection Agency (EPA). If a stream segment, reservoir, or estuary is designated as "impaired," then the state must conduct a TMDL study to determine which pollutants are excessive and must be reduced in order to meet Federal standards.
A waterbody can assimilate some pollution and still meet Federal Clean Water Act standards. According to the Clean Water Act, streams/lakes/estuaries with water quality measured below the minimum Federal standards require Virginia DEQ to act. A clean-up of a waterbody starts with the determination of what pollutant(s) exceed the level which can be assimilated naturally. EPA defines five categories for classifying streams, based on water quality assessments:
In 2008 DEQ found 10,543 miles of impaired streams, 94,044 acres of impaired lakes, and 2,182 square miles of impaired estuaries in Virginia, after assessing "approximately 15,951 miles (31.3%) of the total 51,016 miles of the state’s free-flowing streams and rivers for which sufficient data was available to assess at least one or more designated uses."3
Completing a TMDL, putting the report on a shelf, and then taking no action... does nothing to clean up a water body. As described by Virginia Cooperative Extension, a TMDL Implementation Plan is the document that determines who will have to take action in order to reduce the source of the pollution:4
There is a way to meet EPA's requirements without cleaning up a stream completely. Virginia can change designate uses for a stream, and that alters the requirements (and costs) for clean-up.
After completing a Total Maximum Daily Load (TMDL) clean-up plan and Use Attainability Analysis for surface water bodies that do not meet water quality standards, the State Water Control Board could redefine the intended use and lower the standard (and the costs) to make waters "clean."
Maryland, Virginia, and EPA completed a Use Attainability Analysis and redefined the designated uses for the Chesapeake Bay and its tidal tributaries in 2003. The old standard required 5 mg/L dissolved oxygen year-round throughout all tide-influenced waters, but the "one size fits all" standard did not fully reflect natural conditions. The government agencies decreased the required water quality in the deepwater channels of the bay, allowing a lower level of dissolved oxygen, and increased standards in other areas of the bay.5
An even bolder alteration in standards through a Use Attainability Analysis has been proposed on the other side of Virginia. Straight Creek is a tributary of Powell River that flows for six miles through St. Charles in Lee County, and has been heavily impacted by discharges from coal mines. The unregulated sewage discharges and failing septic systems on Straight Creek will be corrected to reduce excessive bacteria. However, flood control projects created an unnatural channel, with houses built on the original flood plain and minimal tree canopy developed over the relocated stream - and surges of pollution from upstream mining have killed fish in the creek several times.
The mining industry in Southwestern Virginia recognized that correcting the Total Dissolved Solids (TDS) problems and restore a balanced, indigenous population of aquatic life in Straight Creek was a major challenge - and that there were options. In 2007, the VA Coalfields TMDL Group (also known as the Virginia Mining Issues Group) asked DEQ and the State Water Control Board to approve an Aquatic Life Use Attainability Analysis (UAA). The local group sought to reduce the standard for water quality to eliminate the cost for restoring the creek to support any aquatic life (such as dragonflies).6
The industry group asked "Do we really want to force people to relocate so that we can establish a 'natural' stream design? Many of the residences were constructed more than 75 years ago." Changing the stream so the water included lower levels of mining waste (dissolved solids) and creating a more-natural habitat to restore aquatic life "would be a serious financial burden."7
Water "pollution" is a human-centered term, and the standard for Straight Creek may end up being set at a lower level than the standard for most other Virginia streams. While the aquatic life standard for the Chesapeake Bay was adjusted for different parts of the bay, to support different forms of life (with worms and clams in the deep-channel requiring the lowest amount of dissolved oxygen), the requirement to ensure any form of aquatic life may be drppped completely for Straight Creek.
Most pollution is triggered by human-caused impacts. When we strip the vegetation and expose raw soil, rain washes sediment into streams. When our cattle deposit manure on farm pastures (and suburban residents mimic that process by applying fertilizer to lawns), excessive nitrogen and phosphorous moves downhill into our waterways. When ocean-going freighters discharge ballast water in the Chesapeake Bay, we introduce non-native (and sometimes invasive) species.
After coal burns to generate electricity, sulfur escaping up the smokestack creates acid rain. Mercury vaporized by coal combustion is redeposited across the land and directly into lakes, poisoning every waterbody in Virginia. When we hit the brake pedal, the brake pads and tires deposit heavy metals on roadways. Even when cars sit idle, they ooze grease and other petroleum products that migrate into our lakes and creeks.
In developed areas, wastewater treatment plants minimize but do not eliminate contamination from sewage. The basic problem is population growth, with incremental impacts from every new resident. As more people that move into a watershed, the waters experience greater impacts. As the population continues to increase in Virginia, the environmental impacts will grow and grow even if each resident adopts a "greener than average" lifestyle.
People are not the only polluters. Wildlife (deer, geese, mice, snakes, etc.) excrete wastes, but Mother Nature and Father Time can handle the natural levels of pollution. Exposure to sunlight or oxygen as water runs down natural streams will kill harmful bacteria and viruses.
Fortunately, wildlife is rarely concentrated enough to create sufficient waste that affects water quality - predators ensure the critters stay separated from each other. However, urbanizing counties in Northern Virginia and Tidewater are removing massive amounts of natural habitat, concentrating critters unnaturally in the few remaining forested strips along stream channels. Occasionally, DNA tests of water samples that come back with high levels of fecal coliform show the source of the bacterial contamination was geese, raccoons, or other wildlife that had no other place to live or "to go" besides next to the stream.
 wild rice in Quantico Creek estuary |
 test well for contaminants at Occoquan Bay National Wildlife Refuge |
Some phosphorous, nitrogen, and other chemicals occur naturally in Virginia waters. Those chemicals dissolved into solution as the rainwater percolates through the soil and as the groundwater interacts with the bedrock and soil. In karst environments, water is typically "hard" (high in dissolved calcium ions) due to the natural process of limestone being affected by acidic groundwater, which etches away at the bedrock and occasionally forms caves.
In southeast Virginia, the natural decaying organic matter in the Dismal Swamp may interact with the chlorine used in drinking water purification plants. That interaction can create a high level of trihalomethanes, a chemical that could create serious health effects. Residents of the City of Chesapeake claimed that miscarriages were caused by high levels of trihalomethanes in the drinking water from the Northwest River Water Treatment Plant.
Some chemicals have been introduced into the environment, or concentrated far beyond natural "background" levels. For example, rainwater that washes off a lawn, golf course, or soccer field that has just been fertilized will carry nitrates into the local streams and lakes. If someone dumps old motor oil onto a driveway, after changing the oil in their car, then that pollution will seep into the ground and contaminate the water. Plumes of gasoline and heating oil pollution have been mapped, showing the spread of the chemical from leaking undergroud storage tanks.
When we put fertilizer on our lawn, golf course, or farm fields, we add valuable nutrients to the soil for plants to use in growing. Fertilizers advertised as "10-10-10" are advertising the relative percentages of nitrogen, phosphorous, and potassium. (You might also see N-P-K on the bag, using the chemical symbols of those elements.)
However, too much of a good thing can create a problem. If a rainstorm washes the fertilizer that we just spread on the lawn out into the gutter/ditch, those nutrients have been wasted and will end up growing weeds in a ditch, or flow all the way to a stream and change its chemistry rather than help you grow grass or crops.
