(GP/GT) for Additional Water Supply in the Lower Rio Grande

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enjoyment, the propagation and protection of aquatic life, the operation of existing industries and the
economic development of the state .... • Furthermore, •... no waste discharges may be made which will
result in the lowering of the quality of these waters unless and until it has been demonstrated to the
TNRCC that the change is justifiable as a result of desirable social or economic development (TNRCC,
p. I).·
The suggested limitation to thermal pollution as outlined in the Texas Water Quality Standards is of
interest:
1. 2.75"C (5°F) rise over ambient temperature for fresh-water streams.
2. 1.65°C (3°F) rise over ambient temperature for fresh-water impoundment.
3. 2.2"C (4°F) rise or a maximum temperature of 52.5"C (95°) in fall, spring, and winter,
and .85"C (1.5°F) rise or a maximum temperature of 52.5"C (95 D F) in summer for tidal
reaches of rivers and bay and Gulf waters (TNRCC, 1975).
The TNRCC recognized that salinities of estuaries are highly variable and that the dominant factor
affecting salinity variations is the weather. Salinity standards are presently incompletely defmed but are
under study.
The preceding review of the regulations and policies of Texas agencies that apply to the disposal of salt
water indicates that:
1. Temporary salt-water collecting or storage pits are permitted.
2. Salt water treated to remove harmful constituents may be released into bays, estuaries,
and the Gulf of Mexico.
3. Under certain circumstances, the discharge of salt water into natural water courses is
permitted.
4. The reinjection of salt water into saline aquifers is permitted.
5. The lowering of standards for certain water bodies is permitted if sufficient need for
economic development can be demonstrated.
Once again we point out that agencies such as the TNRCC and the Texas Air Control Board no longer
exist as separate entities. Their functions have been absorbed and consolidated into the Texas Natural
Resource Conservation Commission (TNRCC).