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<br />Probable Hydrologic Consequences <br />2. ~COntinued) <br />3. Effects of sed imen[ pond discharges, <br />diversions, and culverts at road <br />crossings on surface water qua llty. <br />4. Effects cf runoff Erom ceclai med <br />areas en the quantity of st reamflow <br /> • <br />'f ABLE 17-29 <br />(Contlnuedl <br />Analysis Results <br />Potential depletions to both Ury or Sage <br />Creeks res ulting from pond storage or <br />production well pumpage will be augmented <br />as outlined In Pea body's approved plan for <br />water rights augmentation. <br />Significance <br />preclude existi nq or potential uses; 2) <br />increases will lessen as flow progresses <br />downstream; and 31 a water-rights <br />augmentation plan has been approved, and <br />will be admi ulster ed during the life of <br />mine. <br />Dtscha cges frem sediment ponds will 6e <br />greatly influenced by spoil water chemistry; <br />however, the Smpacts of thla soo11 water on <br />downstream surface water chemistry has been <br />determined to be of ml nimal significance, <br />although long-term. Ponds during mining <br />will be designed to treat the 10-yea[, 24- <br />hour storm volume, and Peabody will modify <br />the current NPDES permit to include the <br />outfalls of all ponds (005, OOb, and 009) <br />upon completion. All diversions and <br />culverts will be designed to at least pass <br />the 10-year, 24-hour storm, and will be <br />designed to ensure stability and to prevent <br />addlt tonal contributions of sediment. <br />Runoff rates and volumes will be higher than <br />prior to mining, sediment yield will be <br />higher, but sediment concert rat ions will <br />either only slightly increase or decrease <br />significantly. Reconstructed dra Snage <br />channels will be designed to safely pass [he <br />100-year, 24-hour peak discharge, and <br />permanent impoundments will be designed to <br />adequately treat and pass the 100-year, <br />24-hour runoff volume and assoc La fed <br />sediment loads. <br />Sediment pond discharges during mining <br />will have minimal rmpacts due to Peabod y's <br />commitment to Incorporate all outfalls of <br />the ponds in the current NPDES permit. <br />permanent impoundment discharges dominated <br />by spoil water chemis[ryl wilt have a <br />long-term, but minimal irt,pact. Diversions <br />and culverts will have only minimal impacts <br />on surface water quality due to adequate <br />engineering deslgnr and these impacts will <br />last only until they are removed at bond <br />release. <br />Impacts will be long-term, but of mi nlmal <br />sl gn3ficance due to adequately designed <br />postml ning structures (channels and <br />permanent impoundments) <br />N <br />au <br />