(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.

Source Note: The provisions of this §210.23 adopted to be effective February 12, 1997, 22 TexReg 1103