54 



modification to NMFS on May 18, 1994, which extended the 

 exceedance period through June 20, 1994. Both agencies 

 stipulated that TDG levels should not exceed 120% on a 12 hour 

 average at any location in the rivers. 



Spill Management 



Spill' was managed by NMFS through weekly meetings with all the 

 affected agencies. Every Thursday, technical meetings were held 

 to review the biological and physical monitoring data and every 

 Friday in-season management meetings were held to request 

 necessary changes in spill levels. On May 27, as a precautionary 

 measure due to uncertainty about risks associated with the high 

 prevalence of interior signs of gas bubble disease (GBD) , NMFS 

 requested that the spill levels be reduced by one third. 

 Subsequently, the director of the ODEQ issued an order for a 

 reduction of the allowable gas level in the Columbia River to 

 110% TDG, with instantaneous values not to exceed 115* TDG. No 

 other reductions in spill or TDG were made until June 15 when 

 NMFS made the determination that continued spill was unveirranted 

 in the lower Snake River because 95% of' the spring migration of 

 juvenile threatened and endangered salmon had passed these dams. 

 At this time, voluntary spill was ended at Lower Granite, Little 

 Goose, and Lower Monumental dams and cut in half (from 24 hours 

 per day to 12 hours per day) at Ice Heirbor Dam. On June 17, NMFS 

 . terminated voluntary spill at McNary Dam in response to migration 

 status and concern for fish survival under projected low flow 

 conditions in the lower Colximbia River. 



The Monitoring Effort 



A biological and dissolved gas monitoring program was developed 

 by the NMFS amd forwarded to the state water quality agencies on 

 May 20, 1994. An updated version was sent to the ODEQ and WDOE 

 on June 21 which included all revisions made during the spring 

 spill season. In summary, the monitoring plan included: (l) 

 daily external assessment of juvenile in-river migrant condition 

 at five smolt monitoring facilities, four fish guidance 

 efficiency research projects, and two river reach locations; (2) 

 every other day internal assessment of 30 juvenile hatchery 

 steelhead at each of the five smolt monitoring locations; 

 (3) juvenile net pen studies in two das tailraces; (4) periodic 

 monitoring of adult migrant condition at three lower Snake and 

 lover Columbia river dams; and (5) gas supersaturation monitoring 

 at 23 lower Snake and lower Columbia River sites. 



The results of the monitoring effort were reported daily to a 

 vide distribution list and posted on two electronic bulletin 

 boards by the Fish Passage Center. NMFS also issued a daily 

 monitoring report, primarily to Federal fishery and hydropower 

 management agency personnel. On each Thursday, the NMFS report 

 included a memo containing interpretation of the biological data 



