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HomeMy WebLinkAboutAPA2797. • [}{J&fm�£ Cl [§@£®©© Susitna Joint Venture Document Number Please Return To DOCUMENT CONTROL • .. .. . . • . ( OOl�OO�& 0 �®&.�©@ SUSJTNA JOINT VENTURE. INTRA-OFF�CE MEMORANDUM -c;{ 717 An cho rag e Apri 1 23, 1985 LOCATION OATE Filel; 4.3.4.3 TO NUMBER R. Fairbanks Page 1 of 5 FROM Susitna Hydroelectr ic Project SUBJECT ------�----�----��--�------�----��­M eetin g w ith Ri ch a rd B o na r Re g ard i n g the Revelstoke, B.C. Hydro Projec t During my attendance at ·the 21st North American Moose Conference in Jackson, Wy o ming I met Rich ard L.. B ona r of Reve1stoke, British Columbia . Richard, who was a former. employee of B. C. Hydro and Power Authority, presently is a bio logist for the Wildlife Branch of the B.C. Min ist ry of Environment. He has conducted impact assessment studies on moose, bl a ck bear, and other species relative to th e Revels toke Da m on the Columbi a River for about ei ght years. On April 18, 1985 I met with Richard and we discussed his observations and data that were relevant to the Su si tna Project. Bill Steigers of LGL, wh o also p ar t i ci p a t ed in this me et i ng , tape-rec orded most of it. A summary of our discussion is provided be l ow • . A l�c p :-ov i ded is Ri c hard 's address and phone number and the phone nu mber of Keith Simpson, who· was and still is the pri n ci pa l investigator for caribou and grizzly bear on the Revelstoke Project. Richard L. Bonar Box 2624 Addresses/Phone Numbers Revelstoke, B.C. VOE 250 (604) 837-3285 in Revelstoke on weekends (604) 374-9717 in Kaml oop s during the week Keith Sim ps on Revelstoke, B.C. <> C> ( 604) 837-3723 Summary of Mee t i n g Re�Blstoke Project and Study Area (partially fr om Bonar 1983) .. B.C. Hy dro bega n construction of the RPve1�toke Project in southeastern B. C. in 19 77. The 25 mi Z reservoir is about 85 mi. in length and st�2tches between two other Co lumbia River reservoirs including the very large Mica Reservoir at the upstream end.· Reservoir clearing took place 424911/4 .. ,. _ .. .. . . , (}{!£00�& c �00&®©@ SUSITNA JOINT VENTUR E · INTRA-OFF ICE MEMORANDUM Anch o rage Apri 1 23, 1985 . . LOCATION DATE ---------------------------- Files 4.3.4.3 TO NUMBER Ro Fair banks FROM Page 2 of 5 SUBJECT S usi tna Hydroelectric Project Meeting with Richard Bonar Regar ding th e RevelsL; . .:·e, B.C. Hydro Project L r I rc0""' (� ,..- �0 3o '2Y cat � pt� between 1977 and 1983 and fi l li ng was completed in fal l 1983. Water level fluctuation s are slig ht because the proj e c t is operated as a run­ of--the--river project (max. fl uc tua ti o n equal s 15 ft.). The reservoir is in mountainous terrain and is gener ally steep-sided. Terraces, al luvial fa ns, and r ipar ian floodplain s wer e p-:t"ese nt within the mainstem val ley and larger tributaries, and represented the on ly areas of shallow slope. Annual snowfall is heavy w ith snow depths on moose wi nter range usually ex ceeding 40 in . and occasio nally sur passing 75 in for short per iods. Snow often develops a hard crust (since w in ter tem peratures can vary widely) su ff i cient to su pport a moo se. The average Januar�,. temperature at Revel stoke at the downstream end of the reser voir is 21.4°F �rhile at Mica Creek at the upstr eam end the ave rage is 13.3°F. Most of the area is covered by mature coniferous for ests wi th seral stages pr esent on ex tensive logged and bu rn ed areas as well as avala nc h e paths and along wat2rcourses in ri p ar i an assoc iations. The moose po pu l at i o n in the study ar ea was about 250-300 animal s with about two-thirds of those ut i lizing the impoundment zone during winter prior to im pou nd men t. Reservoir Clearing Cl earing took pl ace over a 6-7 year period. First, commercial harvest took pl ace and the n the rem2ining v eg etation was cleared. Essential ly all vegetatio n was rem oved inclu ding sh rubs and herbs. Vegetation was pil ed and burned or buried. Some trac ts of veg etati on that would be well-submerged after fi lling wer e not tota l ly cleared. Also, about a dozen tracts of high qual ity habitats, from a few to sev er al hung red acres 1.n si2le-; wer e reserved from clearing unti l just pri or to imp o un d men t. Clear ing had no measurable effect on the mo o se p op ul at io n lar gely because animals sti ll util ized cleared areas, that rapidly regenerated browse, and the re served tr acts . Moose did not ap pear to be significan tly di s tu �be d by �he clearing ope ration either. Radio-col lared moose were often located wtihin a few hundred yards of clearing operations. Debris did not b ecom e a pr obl em after f il l in g because of the deg ree of cl ear in g and the efforts B. C. Hy dro went to af ter fi lli n g to cl ean-up f lo ati ng debris with booms and boom bo ats with metal rakes, which were used to clean up stranded deb ris . 42491 1/4 f rr-'· b."-1 ., l . . • • ). . , I : J l ·. f}{]£!m�& 0 §(ID£®@@ SUSITNA JOINT VENTURE INTRA-OFFICE ME MORANDUM ·Anchor ag e LOCATION DATE Apr il 23, 1985 F i l es 4.3.4.3 TO NUMBER R. Fairbanks· FROM Page 3 o f 5 Sus{tna Hyd roelec tric Project SUBJECT ---u�������������������� Meeting �ith Rich&rd Bonar Regardidg the Revelst oke, B.C. Hyd ro Project Open Water in Winte r Richard no ted that moose showed no reluct ance to cross the r1ver in winter, prior to inund at ion, even though Mica Dam prod uced 4°C wat er al l winter and kept the river open downst ream. He not ed that they crossed the open reservoir read ily when it was c.old , also. He sa id temperatures ranged down to -20°F in wint er and even at these te mperatures they would readily cross the ri ver which had a wint er flow of 25-30,000 cfs . Richard though t that aside from possi ble habit at ch anges resultin g from flow regulation, open wat er in winter downst ream from a dam would not be detriment al to moose. He sai d that in his stu dy ar ea when snows get very deep, moose will often concent rate along the river or reservo ir shorel ine which is often snow -free due to sli ght water level fluctuation s, and will use this zone as a travel corridor, browsing on ad jacent veget ation, and st aying there for several days or mor e unti 1 travel becomes easier in adjacent forests. Ri chard al so not ed that open wat er in wint er caused by upstream impound ment may increase river otter densities. Alt hough he had no oaseline dat a prior to fi lling Mica Dam, he fel t that river ot ter d�nsi ties were unusually high 1n the stret ch downst ream of the Dam 'oecause of the open wat er in win ter •. Ice-relat ed Problems Richard sa id the reservo ir oft en develops a complete ice cover in wint er but that open wat er and paxt ial ice covers occur as well, depending on the. quit e variable air temperature. Maxj mum ice thickness is about 1 ft. He sa id that moose read ily and easily cross the reservoir on ice when it is st able and generally avoid cross ing when it is not . Oft en the reservoir is mostly ice-covere d except for along the shoreli ne. Moose avoid crossing at that time unless they can find an ice-bridge to the floating ic e. As noted ab ove, they also cross when the reservoir is most ly ice-free and they must sw im. Ric hard noted that he has observed signs of abo ut 20 inst ances where a moose had ven_tured onto the ice and fallen through, in the two winters since the res�rvo ir was fi lled . He felt that these 20 inst ances represe nt ed the major ity of these ca ses. He noted that only 2 mort alities occurred out of t hese 20 cases, and one was associ at ed with the moose get ting tangled in debri s aft er breaking through. He said that, in most cases, as long as ice is st rong enough, 4249 11/4 -. , r . .. ! [}{]£00�& c �(ID£�@@ SUSITNA JOINT VENTURE • INTRA-OFFICE MEMORANDUM LOCATION Anchorage Files Apri 1 23, 1985 DATE 4.3.4.3 . . TO NUMBER --------------------------FROM SUBJECT R. r·airbanks Susit na Hydroelectric Project -weeting with Richard Bonar Regarding the Revelstoke, B.C. Hydro Project Pa ge 4 of 5 the moose can cl imb back out of the water onto the ice after he has broken th roug h, even w�thout a.ny solid footing under the wa ter. He J id he's wat ched them do �t and �t 1 s a slow process, but they ma nage •. He stated that more deer mortalities have been noted (about 10 or so?) bu� that deer te nd to venture out into thinner ice than moose and when they bre.ak th rough they ca n't get back ·out because the ice is .too thin. He noted that the wood land caribou in the area readily cross the reservoir during the winter, when ice conditions permit, in groups of 1 to 20 animals. He said that no ice-related caribou mortalities have been noted. Richard noted that the fractured ice which settles in the large drawdown zone (on the order of 100 ft.) of the Mica Reservoir presents no problems, that he is aware of, to moose or other ungulates. The surface of the ice is general ly rough and the �racks and fissures do not seem to cause these critters any problems. He also noted that he is not aware of any problems related to snowdrifting resulting from winds blowing snow a long or from impoundment zone ice.' \ Summer Reservoir Crossings Moose, bear (both species), and caribou readily cross the reservoir in summer.. Moose crossings were noted in areas where the reservo�r is­ anywhere from 300 yds. to 1 mi. wide. Although these species readily cross the reservoir, their crossing frequency appears to be less than prior to reservoir fillings. This is particularly the case for the bears. No problems have been no ted relative to ungulates and mud-flats (although most soil materials �n the area are c;A rse). Erosion and sluffing cf areas along the steep-sided rese rvoir are common. Population-level Effects Two winters af ter rese rvoir fi lling, population-level effects have not been noted for moose or other large mammals. The 1983-84 winter was relatively mild and the 1984-85 winter was a little more severe than normal. Richard is somewhat puzzled that moose' nu mbers have not yet declined. In addition, he has not seen a redu ction in cow:calf ratios or any problems related to bull:cow ratios. He st.ill expects to see a population-level effect, but wonders why it has not yet occurred. 424911/4 I J ,,.. I I ,. I ! ! j I i � . ,. I . 6 . ... -· ,. . � ' IXJ£00�£ 0 §(ID£®@@ SUSITNA JOINT VENTURE INTRA-OFFICE MEMORANDUM 'A nc ho rage April 23, 1985 LOCATION DATE Files 4.3.4.3 TO NUMBER R. Fairbanks Page 5 of 5 FROM SUBJECT Susitna Hydroelectric Pro j ec t Meeting with Richat d Bonar Regarding­ the R ev e lstoke, B.C. Hyd ro Proj ect Miscellaneous Richard noted that beavers seem to have increased al !>ng the shore lin e since inundation, but he's not sure bow long that will last. He also noted that transmission line corridors in th e area are relatively heavily used by moose 'for foraging as are clearcut s. He noted that aside from the pap er be pr ese nt ed at the 19th North American Moose Conference, no repor ts have been published in the last several years on his studies. He did no te, however, that Keith S im p so n had a few draft re ports p r epar ed on car ibo u and brown bear and that Sim pson gave a paper at a Ca.:-ibou Conference in Mont re al.last year regarding his studies. cc: J. Thral l, HE c. Elliott, HE R. L ind s ay , HE G. G etJ.p er lin e, HE M. Bruin, HE R. Densmore, HE J. Durst, HE P. Am es , HE R. Bonar, B. C. Ministry of Envir onm ent, Wil d life B ranch w. S tei ger s , LGL R. Sener, LGL . . 424911/4 : '