Applicability and scope

Rules in this Subchapter are designed to implement the criteria for dissolved oxygen prescribed in OAC 252:730 Appendix G Table 1 for protection of the beneficial use of Fish and Wildlife Propagation. 252:740-17-2. Regulatory flows (a) The flow in the receiving stream, Qu, shall be deemed to be the greater of the 7Q2 or 1 cfs. If the 7Q2 is unknown, then Qu shall be deemed to be 1 cfs. (b) For industrial dischargers with adequate data as determined by the permitting authority, the effluent flow, Qe, shall be deemed to be the highest monthly averaged flow over the previous two years. For all other discharges, the effluent flow shall be deemed to be the design flow. (c) Provided, in stream segments where dams or other structures have substantially affected the historic flow regime of the stream segment, including but not limited to the portions of the Verdigris and Arkansas Rivers constituting the McClellan-Kerr Arkansas River Navigation System, the appropriate regulatory low flow in the receiving stream, Qu, shall be as determined on a site-specific basis pursuant to properly designed and implemented hydrologic study approved by the permitting authority and DEQ. 252:740-17-3. Reasonable potential determination (a) A permit limit for oxygen demanding substances is required if there is a reasonable potential that the dissolved oxygen criteria will not be satisfied. Such a reasonable potential is demonstrated whenever an existing discharger proposes to increase the concentration or load of oxygen demanding substances, a new discharge of oxygen demanding substances is created, or a receiving waterbody is reclassified to a subcategory of the Fish and Wildlife Propagation beneficial use with a more stringent dissolved oxygen criterion. (b) The permitting authority may base its determination of the reasonable potential upon meeting the dissolved oxygen standard at the applicable regulatory low flow and at the applicable seasonal temperatures prescribed in Table 1 of Appendix G of OAC 252:730. 39 APPENDIX A. [RESERVED] [NEW] 40 APPENDIX B. MEAN HARDNESS (CaCO3) AND pH BY STREAM SEGMENT [NEW] SEGMENT MEAN pH MEAN HARDNESS 120400 7.87 197.40 120410 8.02 262.00 120420 7.77 267.83 121300 7.50 153.00 121400 7.62 170.41 121500 7.47 162.38 121510 7.67 186.00 121600 7.52 169.27 121610 7.40 133.65 121700 7.46 106.55 220100 6.96 25.76 220200 7.74 165.00 220600 7.66 253.48 250510 7.81 294.00 310800 7.89 532.00 310810 7.90 756.44 310830 7.84 924.35 310840 7.96 1137.00 311100 7.86 593.20 311200 7.78 532.94 311210 7.67 470.00 311300 7.65 268.33 311310 7.77 296.00 311500 8.04 838.12 311510 7.95 1041.00 41 SEGMENT MEAN pH MEAN HARDNESS 311600 7.95 1540.00 311800 7.81 2095.00 331510 8.03 1147.00 410200 6.82 32.00 410210 6.89 18.76 410300 7.17 28.42 410400 7.62 192.98 410600 7.84 234.00 520500 7.97 282.00 520520 7.70 344.00 520530 8.07 454.43 520600 8.04 380.00 520610 8.22 442.00 520620 8.08 612.00 520700 7.82 276.16 520710 7.80 272.00 520800 7.69 332.99 620900 8.10 506.01 620910 7.85 802.56 620920 7.99 1297.07 621000 8.08 512.06 621010 8.02 865.00 621100 7.80 367.00 621200 7.83 264.55 720500 8.16 622.00 42 APPENDIX C. INDEX OF BIOLOGICAL INTEGRITY [NEW] 5 3 1 SCORE Sample Composition Total no. of species See figure 1 Shannon's diversity* based upon numbers >2.50 2.49-1.50 <1.50 No. of sunfish species >3 2-3 <2 No. of species comprising 75% of sample >5 4-3 <3 No. of intolerant species <100mi2 area >100mi2 area >5 3-5 <3 See figure 2 Percentage of tolerant species See figure 3 Fish Condition Percentage of lithophils >36 18-36 <18 Percentage of DELT anomalies** <0.1 0.1-1.3 >1.3 Fish numbers (total individuals) >200 200-75 <75 * N n N n - = d i i ln ∑ ** DELT = deformities, eroded fins, lesions, tumors 43 FIGURE 1. Total No. of Species FIGURE 2. No. of Intolerant Species 44 FIGURE 3. Percent Tolerant Species