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

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STREAM DISCHARGE POSSIBILITIES FOR SPENT BRINES, S. TEXAS
Before the advent of environmental regulations that control the discharge of any liquid into flowing bodies
of water, it was generally supposed for most cases that available and nearby streams could adequately
handle most discharges of spent brines from either oil/gas production or from other sources. At present,
there is a growing body of State-level regulations that controls and directs such disposals and we therefore
start this review by presenting relevant excerpts from several agencies concerned with this overall
problem, as seen below.
It must be recognized that it is no longer sufficient to demonstrate that a given quantity of salt water,
containing several inorganic salts not in and of themselves toxic or noxious, will be adequately diluted
by disposal into a very much larger body of flowing water. Today, several factors in the disposal plan
must be weighed and considered in sufficient detail to satisfy the involved agencies that no permanent or
even temporary deleterious effects would arise as a result of stream discharges.
The situation is further complicated by the fact that the total pollution potentials of non-point discharges
into streams (e.g. surface runoff from fields, farms, etc.), although repeatedly studied, still do not lend
themselves to rigorous control except in rare cases where their runoffs are totally prevented from
occurring in the first place. It is clear that the quantities of pollutants thus carried into flowing bodies
of water are far in excess of most single-point or defined-points discharges. A single heavy downpour
can occasion the discharge of several million gallons of water into streams, carrying with it high
quantities of insecticides, pesticides, fertilizers and the like, all of which can pollute under a wide variety
of conditions, to say nothing of sizeable salt leachates from the soil itself.
In the LRGV, in particular, the heavy preponderance of agricultural activities renders non-point
discharges a dominant contributor of stream pollution. Against that background, discharges of up to, say,
thirty acre-feet per day (as estimated from a desalination plant of some 10-15 million gallons per day
capacity) appear to be quite small. Measured against the average flow of water in the Rio Grande, for
instance, these quantities of brines appear insignificant. However, the regulations pertaining to such brine
discharges needs must be obeyed rigorously, if permits for same are to be obtained and maintained.
We begin, therefore, with an extract of these regulations that are pertinent to the case of GP/GT brine
disposal, emphasizing that all of these regulations were historically accurate, but are now totally absorbed
into the respective domains of the TNRCC* Stream Quality Standards Act, the Texas R.R. Commission
and the U.S.E.P.A.
Regulations Governing the Production and Disposal of Saline and/or Geothermal Fluids
Several state and federal agencies including the Railroad Commission of Texas, the TNRCC, and the
Environmental Protection Agency have regulatory responsibilities that directly or indirectly influence
development of both a geothermal test well and, subsequently, a geothermal energy production/generation
facility. Only those regulations that affect the production and disposal of saline water will be
consideredhere. The TNRCC is charged under the amended Texas Clean Air Act of 1967 with
safeguarding the "air resources of the state from pollution by controlling or abating air pollution and
emissions of contaminants ..." (Texas Legislature, 1967). At this time, it is not known if geothermal
fluids will contain any potential air pollutants.
* Texas Natural Resource Conservation Commission