1994-05-19_GENERAL DOCUMENTS - M1977378

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18 ERC 110 ,Vat_-..ac Wildlife Federat:on v. Gorsuch s The rate of oxygen depletion depends serious for at least some dams, and the primarily on the volume of water in the cure is apparently expensive.9 e ; hypolimnion (the more water, the more 2. Dissolved 11inerals and .Vutnents oxygen is available for decom osition), P If dissolved oxygen is totally depleted its temperature (decomposition occurs from the hypolimnion, a further problem more slowly in cold water and colder develops. A number of minerals and - water also contains more dissolved ox - Y plant nutrients, insoluble under normal gen), and the quantity of organic matter it "aerobic" conditions, are soluble in zero- contains (the more organic matter, the oxygen "anaerobic" water. These com- greater the oxygen demands for decom- pounds — including iron, manganese, position). In particular, if the river above and phosphates — therefore tend to be the dam is high in plant nutrients or leached from bottom muds into the reser- �, organic waste when it enters the reservoir ! — whether from pollution or from natu- voir. High concentration of these miner- als and nutrients, released into the down- ral causes — oxygen deletion in the P stream river, can harm fish, make the hypolimnion will be severe.6 water unpalatable for drinking, and foster 1' Several techniques can be used to undesirable plant growth.to � prevent release of oxygen-de leted wa- i P As for low-dissolved oxygen problems ter. First, for many dams, water can be generally, whether mineral leaching will released from the epilimnion (which oc- occur depends on a number of factors, curs automatically for natural lakes). Old- including reservoir size, water tempera- 1('! er dams were built with reservoir outlets Lure, and the quality of upstream water. i I at one level only, usually deep in the dam In addition, mineral leaching depends on so that the outlet would remain below the the amount of leachable matter iri the j surface of the reservoir even in dry years reservoir bottom, which in turn depends when the reservoir was low. vfany newer partly on how old the reservoir is (for an dams, however, have outlets at several older reservoir, most leachable minerals levels, permitting the dam operator to may have already been leached).11 release high-quality epilimnion water. In Control of mineral leaching primarily single-outlet dams, one can aerate the reservoir (by pumping compressed air involves destratifying or mechanically aerating the reservoir to prevent the down to the hypolimnion) or destratify it hypolimnion from becoming totally de- (by pumping cold water from the hypo- pleted, or else discharging water from the limnion to the surface). Alternatively, one can aerate the hypolimnion water as it is the record is an EPA report indicating that in i released from the reservoir, either by 1977, 1576 of water basins in the country ! injecting air or by creating turbulence.7 experienced some sort of water quality prob- The record does not indicate the num- lem caused by dams. Environmental Protec- tion Agency, :National Water Quality Inventory: bey of dams for which discharge of low- oxygen water is a significant roblem, nor 19i 7 Report to Congress 15-19 (Oct. 1978) (EPA P Doc. No. 440/4-7 8-001), J.A. at 200, 202-06 the cost of the various methods of me- [hereinafter cited as EP.1 1977 Report to chanical aeration.8 But the problem is Congress]. 9 See Deposition of Dr.James Whitley, supra H;,drographzc .Clod;;cations 68-7 2 (1973) (EP.� note 8, at 35-38. Dr. Whitley discusses various Doc. No. 403/94i 3-017), J.A. at 207, 221-25 attempts to cure the low-dissolved-oxygen [hereinafter cited as EP.4 1973 Dam Report]. problem below Table Rock Dam in Missouri. 6 Joint Statement of Material Facts, supra One was air-injection, which required 11 large note 4, 1! 19-20,J.A. at 19-20; EPA 1973 Dam diesel air pumps, was "not a very cost effective Report, supra note 5, at 81-82, 87-89, J.A. at method, and ... didn't furnish enough oxygen 220, 227, 237-39. to meet the [water quality] standards." Id. 7 ER4 1973 Dam Report, supra note 5, at 95- at 35. A second was injecting pure oxygen into 97, 109-14,J.A.at 245--17, 259-64. - the intake tubes for the hydroelectric turbines, 8 The district court found that discharge of which met water quality standards but con- low-oxygen water is a "widespread and serious sumed a tank truck of liquid oxygen every problem." 530 F.Supp. at 1299 (footnote three hours when the turbines were operating omitted). However, plaintiffs' only expert wit- at full power. Id at 36-38. As a result, that ness, Dr. Whitley, had personal knowledge of system is now used only in an "emergency." only a small number of dams where release of Id. at 38. low-oxygen water was known to be a problem. 10 EA1 1973 Dam Report, supra note 5, at 75- Deposition of Dr. James Whitley at 25-26 80,J.A. at 214-19. (Aug. 22, 1980). The only quantitative data in 11 Id at 77-78,J.A. at 216-17.