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Steiha 5/30/95 Pag« 10 



Hood Control 



Tho recent indOtsrt of mortaiity in fish p&ns tsoksw ice Hartwr Dam 

 suggests tfiat we should reconsktef spnng flood contro{ ar>d flow augmentaijon 

 strategies. In rrfodsig^t. it se«ms mat bath th« Team and NMFS concentrated on 

 flT« siTuation wfion the years were dry and we r>eed€id to maximize the use oi 

 iiow augmentatioa. Our recant experience wrth involLMTtary spiH ttiat results in 

 ni9h levels of gas supersaturation, shows ttta! NMFS needs ttie abflfty to nsducs 

 rtver flow. The recent fish kjJJ below toe Hartxjr is an exampte whare in-season 

 management decasjocs cooW have reduced ttre ftaw augmentatJor and spiH 

 teveis above loe Hartxx dam sooner wnen the turtJtne pnabtem caused hi^ gas 

 levels tselow the project. As gas saturecion Isvete incroc^s^d Into the lethal range, 

 ftow ftugmectation ahouW have been naduced eocner to decrease the amount of 

 water ttiat rteeded tc be spi^i^ at Ice Hartxx. Also the spilfe that were ordered 

 above ice Hartor contributed to the saiLirafeon tev»J of the waier in ttte forebey. 

 This added to the amount of supersaturation below the project Wrth tt>e present 

 forecast of large invoKjntary spili st the end of May, rt ts a debcale balance to 

 determirva hovr much* nitrogen we take over the short term in antler to redujce the 

 peak total dissoK'ed Qas In ia» May taldng into accotffil of tt>e number of fish In 

 the river. These types of operational decisions are predeeiy what is impHed tjy 

 tt>e term in-season management. 



The high gas lovels at Ice Harbor empha^zes the importance of turbine 

 rnaintenanca and gas abatement measures 3<jch as f^ Bpe". 



DissolvMl Gm Levels 



With your recent request to the Departments of Env<rcwimertal (Xialrty we 

 reco^ze that the numbers in the NMFS Proposed Recovery Plan have been 

 superseded. We have not seen data to indicate th^ 1 1 5% TDG shouid not be 

 ^)piied at aA monitofing stations and the use of 1 20% as ttw lirnt in the taiirace 

 concerns us. Wa undersartd that internal moortoftng d gas bubble trauma will 

 be carried out by the Nationai Bioiogtcai Servk». We teal that last year's 

 recorrmendations of NMFS's Expert Panel on [>sso<v»d Gas shoukj be fuJty 

 imptomented as soon as possib^. This «41 require internal montorfng In order to 

 detenrane the stese of vasouiar tissue. The Expert Panel cafled for examination 

 of f^sh obtained frxxn the ooUector systems as we4( as the fofvbay so we can 

 detdrmine \t bubbles are removed t>y ctecomprasston rn the collector system. 

 Technique that win not introtljce bubbles, (i.e. exsmffiation of giS larneSae), wiH 

 Oe used wMh eaimon as well as steei^ead We eUso recommend thai haichery 

 steetnead be sacrlflced for internal samples a^ that similar live samples be h«ld 

 in the rivor to piravide a rr«asure ot nvartatity. WHh the almost certafnty o* high 



