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Apart from point-source discharges, toxics and other pollutants can enter surface water through urban and agricultural runoff, seepage from land-fills and hazardous waste facilities, spills on land
or water and seepage from underground injection sites. They can also be carried by acid rain, which occurs when air-born contaminants are absorbed by clouds and return to earth in the rain. The impact of non-point-source pollution on water quality is significant: the EPA now estimates that non-point-source pollution accounts for 65 percent of pollution in rivers, 76 percent in lakes and 45 percent in estuaries in the United States.(53)
The 1987 amendments to the Clean Water Act were the first comprehensive attempt by the federal government to control non-point-source pollution (NPS) from urban streets and sewers as well as from agricultural activities. The law requires states to conduct an assessment of waters contaminated by non-point-source pollution and to devise best manage- ment pollution-abatement plans to help clean these waters up. The law also provides funding to the states for up to 60 percent of the cost of implementing these plans. Between 1990 and 1993, Texas received about $2 million in federal funds for a variety of abatement programs.(54)
In addition to this federal money, the state supports some pilot projects to control non-point-source pollution. Finally, some local governments have adopted their own non-point-source pollution abatement programs.
In Texas, the 1995 Water Quality Inventory and a 1990 non-point-source report show that urban and agricultural run-off has helped pollute 26 percent of the impaired river miles, 17 percent of the impaired reservoir acres and 15 percent of the square miles of impaired estuarine waters.(55) (Another 566 miles of impaired river and streams due to unknown sources may also be related to non-point-source pollution.) However, it is important to note that these percentages are based upon suppositions. Even so, actual effects of non-point-source pollution on Texas' surface waters are probably much greater. Despite these documented effects on Texas rivers, lakes and streams, pollution abatement and management plans have not been implemented in most areas in Texas. Part of the difficulty is identifying the origin of the non-point-source pollution that affects water quality. One of the major purposes of the state's 1991 Clean Rivers Act - which requires river authorities to assess the water quality of their river basins - is to establish better data regarding non-point-source causes and impacts. Though it is by definition difficult to pinpoint where non-point-source pollution originates, most such pollution can be grouped into two broad categories: agricultural and urban.
Agricultural activity accounts for most of the reported cases of non-point-source pollution in Texas.(56) The irrigation of crops, the application of fertilizers to pasture or range land and the use of feedlots all generate such non-point-source pollutants as plant nutrients, pesticides, sediment and animal waste.
Confined Animal Feeding Operations
A major contributor of non-point-source pollution are Confined Animal Feeding Operations (CAFOs), facilities that house in a relatively concentrated area animals used for the production of eggs, milk and meat. Confined Animal Feeding Operations generate a variety of potential pollutants. Animal waste contain pathogens, chlorides and potassium salts and high levels of nitrogen. Confined Animal Feeding Operations may degrade state waters by increasing nutrient loads and fecal coliform in many rivers. This type of contamination ultimately lowers dissolved oxygen levels, which threatens the viability of aquatic habitats and consequently the use of the river for fishing, swimming or drinking.
State regulations now prohibit these facilities from discharging wastewater or animal waste directly into streams and rivers. Operators must also not allow the waste to run off the site, where it could contaminate surface or groundwater. Currently, all large Confined Animal Feeding Operations must obtain a no-discharge permit from the state, which requires that they control runoff except when there is excessive rain.(57) Most large cattle operations are located in the Panhandle, while dairy farm operations are concentrated in Erath County, near Stephenville.
Even the smaller non-permitted Confined Animal Feeding Operations are expected to comply with the no-discharge policy. The state can initiate an enforcement action on these facilities if they discharge into the state's waters.
In 1993, the Texas Legislature transferred much of the responsibility for regulating non-permitted, smaller Confined Animal Feeding Operations from the Texas Natural Resource Conservation Commission to the Texas State Soil and Water Conservation Board. The move was designed to change the state's oversight of these operations from a traditional regulatory role to a technical assistance role. The Soil and Water Conservation Board is expected to help agriculture adopt better run-off control practices, mainly through Waste Management Plans, allowing them to come into compliance voluntarily.
Source: John M. Sweeten, Charles Baird and Leah Manning, "Animal Waste Management," Agricultural and Silviculture Non-Point-Source Pollution Management, # L-5043 (Temple: Texas State Soil and Water Conservation Board and Texas Agricultural Extension Service, 1991), 1.
This animal waste is often used to fertilize crops, and if overused, can lead to polluting runoff. Animal wastewater is often collected in ponds for use in irrigation. These holding ponds - which are intended to prevent run-off - can overflow with heavy rainfall, or may leach into the soil, eventually contaminating groundwater.
The Texas Natural Resource Conservation Commission has developed "best management practices" for Confined Animal Feeding Operations designed to limit runoff. These practices include:
Surface water in Texas has not been extensively monitored for pesticides. However, arsenic, which is used in some pesticides, has been identified in several counties as a surface water concern. About 5 percent of total samples taken by the state between 1968 and 1990 exceeded the drinking water standard of 50 ug/L for arsenic. Since arsenic occurs naturally and is also an industrial pollutant, it is difficult to pinpoint the source of arsenic in surface water. Most of the samples that exceeded standards were collected in counties with high industrial activity as well as agricultural production.(61)
|EXAMPLES OF NON-POINT-SOURCE POLLUTION CONTROL PROGRAMS IN TEXAS|
|Federally Funded Projects
State Funded Project
Texas has funded a study of run-off from El Paso-area colonias, or unincorporated communities along the U.S.- Mexico border that lack adequate wastewater treatment.
Local Pollution Abatement Program
Under state regulations, municipalities have the authority to adopt ordinances designed to protect water quality. In Texas, the two cities which have adopted the most far-reaching regulations to protect water quality are Austin and San Antonio.
The City of Austin has adopted an ordinance designed to prevent development from affecting stream water quality in the sensitive Barton Springs watershed. The controversial ordinance, passed by voters in 1992, limits impervious cover - the percentage of land covered by pavement or buildings - in any new development along the watershed of Austin's streams and creeks. Impervious cover cannot exceed 15 percent in the recharge zone of Barton Springs and 25 percent in the Barton Springs/Edwards Aquifer contributing zone, which feeds into Barton Springs.(58)
In San Antonio, where the Edwards Aquifer is currently the sole source of water, a new water quality ordinance approved this year by the City Council expands zoning authority within city limits. The water quality ordinance also places limits on impervious cover in areas of the city's extra-territorial jurisdiction (ETJ) which are located above the aquifer.
Cities which have a population more than 100,000 must obtain a stormwater discharge permit from the EPA under the National Pollutant Discharge Elimination System (NPDES). Also requiring an National Pollutant Discharge Elimination System permit are all construction projects that disturb more than five acres of land. Thus, stormwater is a permitted point-source, despite the non-point-source nature of the contamination itself.
Under the National Pollutant Discharge Elimination System permit, large cities and construction companies are required to treat stormwater and develop management techniques to address these pollution sources (see box).
Construction, Pollution and Impervious Cover
Construction, especially that associated with highway building, can also be a major source of sediment and other non-point-source pollution. The Texas Department of Transportation requires contractors to meet standards for mitigation of construction run-off during roadwork, but many environmentalists consider these standards inadequate. They argue that construction and development inevitably increase impervious cover, which prevents rain from being absorbed into the ground and thereby increases runoff that can contaminate streams and rivers.
Section 26.177 of the Texas Water Code will require all Texas cities with a population of more than 5,000 to submit a pollution abatement plan to the Texas Natural Resource Conservation Commission. These abatement plans must address both storm sewer discharges and urban runoff.(63)
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