| (a) Except for authorized on-channel ponds, storage
facilities for retaining reclaimed water prior to use shall not be
located within the floodway.
(b) Except as provided by subsection (e) of this section,
all initial holding ponds must be lined in accordance with either
subsection (c) or (d) of this section, as appropriate.
(c) All initial and subsequent holding ponds containing
Type I and Type II effluent, located within the recharge zone of the
Edwards Aquifer, as defined in Chapter 213 of this title (relating
to Edwards Aquifer), and all initial holding ponds containing Type
II effluent, located in a vulnerable area as defined by a rating of
110 or greater on the statewide "Ground-Water Pollution Potential--General,
Municipal, and Industrial Sources" (DRASTIC) map (as shown in Figure
1 of this chapter), shall conform to the following requirements:
Attached Graphic
(1) The ponds, whether constructed of earthen or other
impervious material, shall be designed and constructed so as to prevent
groundwater contamination;
(2) Soils used for pond lining shall be free from foreign
material such as paper, brush, trees, and large rocks;
(3) All soil liners must be of compacted material,
at least 24 inches thick, compacted in lifts no greater than six inches
thick and compacted to 95% of Standard Proctor Density. In-situ clay
soils meeting the soils liner requirements shall be excavated and
re-compacted a minimum of six inches below planned grade to assure
a uniformly compacted finished surface.
(4) Soil liners must meet the following particle size
gradation and Atterberg limits:
(A) 30% or more passing a number 200 mesh sieve; and
(B) a liquid limit of 30% or greater; and a plasticity
index of 15 or greater and have a permeability less than or equal
to 1 X 10-7 cm/sec;
(5) Synthetic membrane linings shall have a minimum
thickness of 40 mils with a leak detection system. In situ liners
at least 24 inches thick meeting a permeability less than or equal
to 1 X 10-7 cm/sec are acceptable alternatives;
(6) Certification shall be furnished by a Texas Registered
Professional Engineer that the pond lining meets the appropriate
criteria prior to utilization of the facilities; and
(7) Soil embankment walls shall have a top width of
at least five feet. The interior and exterior slopes of soil embankment
walls shall be no steeper than one foot vertical to three feet horizontal
unless alternate methods of slope stabilization are utilized. All
soil embankment walls shall be protected by a vegetative cover or
other stabilizing material to prevent erosion. Erosion stops and water
seals shall be installed on all piping penetrating the embankments.
(d) All initial holding ponds designed to contain Type
I effluent, located outside of the recharge zone of the Edwards Aquifer,
and Type II effluent, located in areas in the state not identified
in subsection (c) of this section shall conform to the following
requirements:
(1) The ponds, whether constructed of earthen or other
impervious materials, shall be designed and constructed so as to prevent
groundwater contamination;
(2) Soils used for pond lining shall be free from foreign
material such as paper, brush, trees, and large rocks;
(3) All soil liners must be of compacted material having
a permeability less than or equal to 1 x 10-4 cm/sec,
at least 24 inches thick, compacted in lifts no greater than 6 inches
each;
(4) Synthetic membrane linings shall have a minimum
thickness of 40 mils. In situ liners at least 24 inches thick meeting
a permeability less than or equal to 1 X 10-4 cm/sec
are acceptable alternatives;
(5) Certification shall be furnished by a Texas Registered
Professional Engineer that the pond lining meets the appropriate criteria
prior to utilization of the facilities; and
(6) Soil embankment walls shall have a top width of
at least five feet. The interior and exterior slopes of soil embankment
walls shall be no steeper than one foot vertical to three feet horizontal
unless alternate methods of slope stabilization are utilized. All
soil embankment walls shall be protected by a vegetative cover or
other stabilizing material to prevent erosion. Erosion stops and water
seals shall be installed on all piping penetrating the embankments.
(7) An alternative method of pond lining which provides
equivalent or better water quality protection than provided under
this section may be utilized with the prior approval of the executive
director.
(8) A specific exemption may be obtained from the executive
director if, after the review of data submitted by the reclaimed water
provider or user, as appropriate, the executive director determines
containment of the reclaimed water is not necessary, considering:
(A) soil and geologic data, and ground water data,
including its quality, uses, quantity and yield; and
(B) adequate demonstration that impairment of ground
water for its actual or potential use will be prevented.
(e) Reclaimed water may be stored in leak-proof, fabricated
tanks.
(f) Subsequent holding ponds utilized for the receipt
and storage of reclaimed water of a quality that could cause or causes
a violation of a surface water quality standard or impairment of ground
water for its actual or intended use will also be subject to the storage
requirements of this section.
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