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Under Section 303 (d) of the Clean Water Act, the State of Texas must identify which stream,
reservoir, and bay segments have been impaired by pollution and do not meet their designated water uses—such as aquatic life or contact recreation. For 2002, the TCEQ has
confirmed problems in 299 river, stream, bay, reservoir or ocean segments or parts of segments in Texas that do not support, or only partially support, their designated use.* Note: Many of the 299 represent only a small part of a segment in which there are confirmed problems).*
Under a 1991 state law, local river authorities and coastal basin authorities are required to
assess their river basins every two years, identifying major water quality issues. In 1992 all river authorities identified lack of monitoring, and the resulting limited water
quality data, as the major water quality issue.* The 1992, 1994, and 1996 assessments demonstrated that elevated levels of nutrients
and fecal coliform bacteria continued to be the most common water quality problems affecting state waters, while in West Texas, salinity (total dissolved solids) is one of the largest
concerns.* In addition, low levels of dissolved oxygen continue to be an issue for rivers and streams throughout Texas.
Fecal coliform and E. Coli in inland streams and enterococci in tidal streams are indicators used to determine whether
streams and rivers are safe for swimming since they are an indicator of other pathogens that cause infectious diseases.
Such bacteria commonly enters streams and rivers through inadequately treated sewage, an overabundance of wildlife,
and runoff from pastures, feelots and urban areas. In 2002, the TCEQ reported that 177 streams and rivers --covering
over 2200 miles -- did not meet water quality standards because of high elevated bacterial densities in water, while
another forty-two streams had elevated levels of pathogens but did not have enough samples taken to place them on
the "impaired" list, while another 42 stream and river segments were placed on a "Tier II" concern list, meaning there
was potential for problems with pathogens though not enough problems to constitute an impairment. In fact, elevated
levels of pathogens were the leading cause of impairment in Texas' rivers and streams.* Texas reservoirs, however,
do not appear to have major problems because of high level of pathogens.
Despite limited monitoring, toxics have been identified as a major concern in a number of rivers. Seven rivers have
been identified as not meeting their aquatic life uses due to high levels of metals in water, incuding the Wichita River
and Middle Fork Wichita River due to selenium concentrations, the Neches River below Lake Palestine due to lead
concentrations, and the Neches River above Lake Palestine due to high zinc levels. In addition, 16 other river or stream
segments did not have sufficient data to be considered impaired, but were identified as water quality concerns, mainly
due to metals in water. Only one of these was identified as a concern due to organic contamination -- the Neches River Tidal with a concern for malathion.* However, very limited monitoring data was available for organics. In addition, five
river or stream segments were put on the list for ambient toxicity in the water which impacts wildlife.
In addition to the limited toxicity monitoring, the TCEQ keeps tabs on fish kills, since they are an indicator of the impacts
of pollution, although it is extremely difficult to determine whether pollution, natural causes or both cause fish kills.
Some 92 percent of the 358 fish kills reported in the past five years are believed to be due to five causes—depletion of
levels of dissolved oxygen (40 percent), toxics (20 percent), physical damage such as changed habitat (10 percent),
unknown causes (14 percent), and disease -- including biotoxins such as the toxic golden alga Prymnesium which
caused massive fishkills in the Brazos River Basin. Most of the toxic fishkills were due to petroleum product spills or chlorine. In all, over 83 million fishkills were reported.* In two water bodies, the Rio Grande downstream of
Laredo-Nuevo Laredo and the Alligator Bayou in the Neches-Trinity coastal river basin, unusually high numbers of fish abnormalities may indicate the presence of toxic pollutants.* Significant testing of the water, sediment and fish tissue is being undertaken to determine the root cause of these fish abnormalities.*
Depressed dissolved oxygen levels have been identified as a concern or the cause of actual impairment in most Texas
river and coastal basins.* This condition, also referred to as high biological oxygen demand (BOD), is considered one of
the most obvious indicators of degraded water quality because it directly impacts aquatic life. For its 2002 report, the
TCEQ found 22 freshwater streams or rivers with depressed dissolved oxygen concentrations, as well as seven tidally
influenced waterbodies. Many of the impaired streams occured in the slow-moving streams of East Texas. In addition,
the TCEQ identified 18 other streams and rivers with depressed oxygen levels, but with insufficient data to determine
compliance with the standard, as well as 109 other stream and river segments where a concern had been identified for
low dissolved oxygen levels, though not sufficient to be considered "impaired."* Only four reservoirs -- Caddo Lake,
Lake Wright Patman, Toledo Bend and Inks Lake -- had identified water quality problems with depressed oxygen levels.
Twenty-six of the river basin areas identified high levels of nutrients—usually phosphorus, nitrogen, ammonia, and
nitrates—as a water quality concern or possible concern. Wastewater discharges, improperly functioning wastewater
systems, septic tanks, agricultural runoff, and other kinds of non-point-source pollution were identified as probable
sources of these nutrient loadings. Excess nutrients in water can cause growth in aquatic vegetation, which reduces
dissolved oxygen in rivers and streams, affecting fish and other aquatic species. In 2002, TCEQ found 13 reservoirs
with concerns for elevated levels of ammonia nitrogen, 22 reservoirs for concerns with high concentrations of nitrogen
(nitrite plus nitrate), 10 with excessive levels of orthophosphorus and and 14 for total phosphorus.* In addition,
between six and 15 percent of the total river miles assessed for nutrient concerns had high levels of one of the four main nutrient indicators.
Degradation of habitat is a major water quality concern. Development, erosion, and the dredging and filling of coastal
areas have destroyed some animal habitat in rivers and streams. The Sabine River Authority conducted ambient toxicity
and rapid bioassessment studies to determine impacts of toxic pollution and non-point-source pollution on biological
health. The tests revealed several areas of concern or biological impairment throughout the basin.*
In addition to water quality problems identified by river authorities, excessive levels of toxics such as metals, PCBs and
pesticides in edible fish tissue has led the Texas Department of Health (TDH) to issue "aquatic life closures" or total
bans on consumption of fish and shellfish in one bay—the upper portion of the Lavaca Bay due to elevated mercury
levels—five reservoirs or irrigation systems, and four river segments of the Trinity River (see Coastal Resources section
for details on bays and estuaries). In addition, the TDH has issued fish-consumption advisories -- with a
recommendation for restricting consumption of fish from the waterbody -- for 26 other water bodies, including portions of the Gulf of Mexico.*
Fishing in areas closed to fishing is a violation of state law. Most recently, in 2002, the Texas Department of Health
reissued a ban for about 60 miles of the upper Trinity River due to elevated levels of chlordane, PCBs and other toxic
substances and added several lakes in East Texas, including Pruitt, Ratcliff, Meredith and Lake Daingerfield, to the list of waterbodies with advisories due to high mercury levels.
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