101 



THE GAS MONITORING/SPILL MANAGEMENT PROGRAM 



The spill monitoring program was developed over a period of 10 months and built 

 upon the lessons learned m the 1994 spill program. Its purpose is to ensure that 

 the spill program does not harm migrating juvenUe salmon oy causing gas bubble 

 trauma. The monitoring program is explained in detail in NMFS' Spifl Monitoring 

 Working Document (April 7, 1995). The monitoring closely follows the recommenda- 

 tions of two separate panels of gas bubble trauma experts Uiat NMFS convened in 

 1994. The program has been comprehensivdv evaluated by a Gas Bubble Trauma 

 Technical Work Group (co-chaired by NMFS and the Environmental Protection 

 Agency), and provided to the Oregon State Department of Environmental Quality, 

 and the Washington State Department of Ecology. 



The monitoring program has two components: biological and physical. The biologi- 

 cal monitoring consists of sampling juvenile migrants at several locations and exam- 

 ining them for both internal and external signs of gas bubble trauma. Also, resident 

 fish are periodically examined for the same symptoms, total dissolved gas is phys- 

 ically monitored by instruments in place both above and below each dam. 



In addition, though they are not strictly a part of the monitoring effort, several 

 research studies related to the biological impacts of gas bubble trauma are presently 

 underway. These include: using hateheiy steelhead to develop a non-lethal proce- 

 dure for measuring gas bubbles in gill maments; holding resident fish species and 

 hatehery-reared chinook salmon in net-pens below two dams and in one reservoir 

 and regularly observing them for gas bubble trauma; identifying the most important 

 signs of gas bubble trauma and determining their prognostic value; observing the 

 length of time that radio-tagged individuals spend migrating through a collection 

 system; examining total dissolved gas distribution in reservoirs relative to fish dis- 

 tribution; and comparing the prevalence of gas bubble trauma in fish captured in 

 selected dam forebays to the prevalence of gas bubble trauma in fish collected in 

 dam bypass systems. (This latter research is critical because preliminary laboratory 

 observations suggest that bubbles may disappear (i.e., collapse) as fish pass a dam 

 via a bypass system.) 



The spill monitoring program and its associated research has provided the operat- 

 ing agencies with iniormation used to adjust spill on a weekly and even a daily 

 basis. The monitoring in 1995 has found that less than one percent of the 

 outmigrating salmon are exhibiting any signs of gas bubble trauma. As recently as 

 last year, it was not possible to make such a stetement with any degree of certainty 

 because comparable data did not exist. As the spill program continues, new informa- 

 tion will emerge from the attendant monitoring and research. This information will 

 be used to continuously redesign the operations to reduce the potential for harm 

 fix)m gas supersaturation. 



The monitoring program has shown that, despite involuntary spUl at several dams 

 this spring and very, nigh concentrations of dissolved gas at Ix;e Harbor, only an ex- 

 tremely low frequency of gas bubble trauma has been observed. Between May 1 and 

 June 1, over 24,360 river-run juvenile salmonids were examined at the dams, and 

 only 0.2 percent showed any signs of gas bubble trauma. Of these, 0.06 percent of 

 17,657 juveniles showed exterior gas bubble trauma signs, 0.6 percent of o055 juve- 

 niles exhibited at least one bubble internally in the lateral line, and 1.7 percent of 

 657 iuveniles had at least one internal bubble in the gill lamellae. Furthermore, no 

 gas bubble trauma signs have been recorded in the several hundred adult salmonids 

 examined at Lower Granite and Bonneville Dams. 



In-Season Management 



A technical management team (TMT), comprised of NMFS, Corps, the Bonneville 

 Power Administration, Bureau of Reclamation and U.S. Fish ana Wildlife Service, 

 meets at least once a week to review the most recent data on runoff, the system 

 operations, dissolved gas levels, and numbers of salmon migrating in the river. The 

 TMT prepares recommendations on spill, reservoir operations, ete. The purpose of 

 these meetings is to improve fish passage to the greatest extent possible while man- 

 aging the system to remain witJiin stete water quality stendaros for dissolved gas. 

 The meetings also provide a forum for stete and tribal fisheries managers to make 

 recommendations on system operations. The Corps of Engineers and the Bureau of 

 Reclamation, who are responsiole for the operation of the dams, make the final deci- 

 sions on how the system is to be run. Thus, spill management in 1995 is a highly 

 integrated and adaptive process. It operates using the latest date, and operational 

 adjustmente are made rapidly. 



Ice Harbor 



An example of the spill program's real-time operational flexibility is seen in the 

 incident that occvured at Ice Hai-bor Dam earlier this summer. In that instance, tur- 



