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HomeMy WebLinkAboutEvaluation of ice problems Hydro in AK 2 of 3 1982FINAL REPORT TO THE STATE OF ALASKA DEPARTMENT OF COMMERCE AND ECONOMIC DEVELOPMENT Hydroelectric Icing 08-73-7-958/08-71-6-114 or Contract AEC81005-3 EVALUATION OF ICE PROBLEMS ASSOCIATED WITH HYDROELECTRIC POWER GENERATION IN ALASKA: FINAL REPORT TO THE STATE OF ALASKA, DEPARTMENT OF COMMERCE AND ECONOMIC DEVELOPMENT by J. P. Gosink and T. E. Osterkamp Contents Summary Appendices 1. A Survey of Ice Problems at Hydroelectric Facilities 2. Results of Questionnaire Study of 26 British Columbia Hydroelectric Stations 3. Ice Problems at Swedish Hydroelectric Plants 4. Length of Open Water Reach Below a Dam or Reservoir 5. List of Published Articles SUMMARY Information regarding ice, its adverse effects upon hydroelectric facilities, and reliable methods to minimize these effects is sparse, located in obscure references or proprietary. As a result, the engineering information and expertise necessary to deal with ice problems is not normally found in U.S. engineering firms. Since there has not been any hydroelectric development in Interior Alaska or along its colder coasts, there is no core of engineering experience to draw upon. The primary objective of this project has been to acquire, document and develop the necessary engineering information base to be used by hydroelectric power planners, designers and operators to eliminate, avoid or reduce ice problems associated with hydroelectric power production in Alaska's cold winter climate. We proposed to accomplish this objective by compilation of state-of-the-art engineering information, applied research where appropriate and publication of reports summarizing current world-wide engineering practice and research information. During the first two years of this project, reports were published which include: I. A survey of manufacturers, available equipment, applicability (head, discharge, KW) and experience with northern climates; 2. A bibliography listing sources of information on small hydropower with critical annotations regarding the usefulness of each; 3. A brief survey of ice problems and mitigating procedures in hydroelectric facilities in Canada, Switzerland, and Scandinavian countries. This final report completes the limited objectives for this project as set out in the revised work plan May 28, 1982. These objectives, including the complete survey of ice problems and mitigation procedures at hydroelectric sites in Sweden and British Columbia, and the development and documentation of a water temperature model for downstream thermal predictions, are addressed in appendices 1 through 5 of this report. These appendices represent both compilations of existing international engineering experience and methodology, and original applied research. The knowledge gained regarding ice problems should be made available to Alaskan hydropower engineers and planners. Correct site selection procedure, knowledge of potential problems and the means to alleviate those problems is of great benefit to Alaska. This information will allow rational management decisions to be made both in the planning and operational stage of hydroelectric development. Appendix 1 A Survey of Ice Problems at Hydroelectric Facilities: Report to the State of Alaska Department of Commerce and Economic Development by Greg Penn T. E. Osterkamp J. P. Gosink Geophysical Institute University of Alaska Fairbanks, Alaska 99701 •saLgtLtDPJ uamodoupkq og sgLsLn Lpuosuad pup `Lauuosuad queld uarood ggLM suoLgpsuanuoo auogdaLag `uaModoupRq ggLM 6uLLpap aLdoad wou3 paALaaau suaggaL 'saLupdwoD X4LB*4n pup sgupLd AaModoupkq og guas sautpuuoLgsanb daLuq wou3 pauLpggo spM Fanuns aq-4 uo} uotgpwuo3ui aouapLDuL PUP kgLuanas ALagq pup aup saLgLnoL}JLp asogg gpqM agp0LpuL og pup gsLxa op saLgLn3Ld3Lp gpgg Mogs og sL uadpd aqg 40 guaquL 941 •waLgoud aqg paouaLuadxa anpq og uMou) squpLd Aamodoupkq }o gsLL p Rq paMoLLo3 sL suoLgnLos aLgLssod pup waLgoud p 30 uoLgdLuasap 3aLuq y •6uLnp4 aup uo ppg anpq sgupLd uaModoupFq gpgg swaLgoud aot Jo SaAuns p sL SL41 •saLaLLLop3 6utgsLxa uo3 pup 6ULuupLd uo} Ln}asn aq pLnoM Fanuns aq1 •wagq ggtM Lpap og Moq pup tnD:)o oq FLa�LL aup swaLgo.Ad gpqM k3LguapL dLag upa suoL6au uuagluou uL sgupLd uaMod 6uLgsLxa Rq paouaLuadxa saL2Lno1J�tp 30 SaAuns y •aI M LLo PLOD QaA p uL gupLd uaModoupkq p Jo uoLgonugs -UO3 6uLuuL6aq auo3aq passauppp aq og paau kagg qnq °ggLM gLpap aq upo PUP aLgpnLos uagjo aup swaLgoud aq1 •sgupLd uaALu-jo-unu uo oupFg LLpws uo3 RLLPLoadsa °auanas aq upo swaLgoud asagl •swaLgoud LPLoads awos asod sagpwLLo PLOD `uanaMO[j •P�SPLV k[JPLnoLgupd °suoL6au uuagguou uL sgupLd uaModoupkq LLpws 6uLgstLgpqsa uL gsauaguL awos uaaq spq aua41 Intake Blocked With Ice A common problem is the build up of frazil ice on intake trash racks. Frazil ice is produced in the absence of ice cover in turbulent, supercooled water. The small ice crystals are carried downstream where they are drawn into intakes and cling to the trash racks. Build up can be rapid resulting in reduced or no flow to the turbines. Intakes can also be damaged or blocked by surface ice on a reservoir as the water level drops to or below the intake. The problem of ice on the trash rcks has been dealt with successfully in many cases, but it still causes difficulties under certain conditions. Some methods of preventing ice blocking the intake are heating trash racks, back flushing, creating an ice cover to minimize frazil production, lowering the intake water velocity to decrease drawdown and ensuring that intakes are in deep water. Gold Creek Juneau, Alaska 1.6 MW maximum Dewey Lakes Skagway, Alaska 30-375 kW Manitoba Hydro Newfoundland and Labrador Hydro Forces Motrices de Mauvois in Switzerland 3 plants 835 million kWh Soderfors DalalvenRiver Sweden The problem is not severe in this case since the plant is usually shut down due to low flow when it is cold. Here the water level in the reservoir must be watched to ensure it is deep enough to minimize frazil ice and to keep surface ice above the intakes. Frazil ice on the trash racks. Trash racks have been heated to minimize the problem. Spillimacheen Columbia River British Columbia, Canada 5MW Western Mica British Columbia, Canada Bennett Dam Peace River British Columbia, Canada Trash racks have been heated to minimize the problem. Air bubblers are used to prevent icing at the intake. Rapid ice formation in temporary diversion tunnels threatened flooding during construction. Flooding Caused by Ice Hanging dams, ice jams, anchor and frazil ice can restrict the flow in the normal river channel causing floods. The floods are sometimes severe and damage property including the power station. Careful planning is needed so that equipment and structures are above possible flood levels. Blasting with dynamite to break up ice jams has been frequently tried. Ice booms have been used to help establish a stable ice cover. Often, water that normally goes through the turbines must be either stored in the reservoir to float ice jams free or used to float ice masses over a spillway. This can reduce power output significantly. Dikes have been built to prevent property damage from floods. Manitoba Hydro Winnipeg, Saskatchewan, and Nelson Rivers Irve Tolles Real Data, Inc. Manchester, N.H. Town of Peace River British Columbia, Canada Near the Bennett Dam Town of Taylor British Columbia, Canada Near the Bennett Dam Ice damming "has become very critical on several occasions necessitating the mobilization of forces to prevent the topping of coffer dams". A plant under construction would have had water level controls damaged if they had been in place. Floods in 1973 and 1974. Dikes have prevented the problem since. A cold snap in 1979 caused increased electrical usage which necessitated greater discharge from the turbines. This affected the ice front upstream of Taylor producing a large ice jam that caused a flood with an 18' rise in 48 hours. Carefully controlling the discharge minimizes this problem. Icing of Structures from Spray Falling water at a dam or falls creates spray which wets nearby structures. When the spray freezes, it can damage those structures, often due to the weight of the ice on them. An icy coating can also be hazardous to people who must work in the area. Usually the ice is manually chipped away when it becomes a problem. Heating structures to melt the ice is also a possibility. Pidgeon River Plant Vanderbilt, Michigan 11-100 kW Forces Matrices de Mauvoisin Switzerland 3 plants 835 million kWh Manitoba Hydro The problem is minor. Pelican Creek A leaky woodstove penstock ices a Pelican, Alaska walkway making its use hazardous less than 500 kW and difficult. Shut Down Due to Low Flow in Winter The water supply to a power plant usually decreases in the winter in cold climates, often drastically. Decreased output or complete shut down result. Low flow in a pipe increases the danger of freezing in the pipe. Water storage in a reservoir or piping water in from other drainages can help make up for periods of low flow. Pelican Creek Pelican, Alaska less than 500 kW Gold Creek Juneau Alaska 1.6 MW maximum Dewey Lakes Low flow increases the danger of Skagway, Alaska pipes freezing. Pipes have split 30-375 kW and the plant has been close to shutting down on several occasions. Significant energy is used to heat pipes. Open Water Downstream In the winter, when warm water (4°C) is discharged downstream of a power plant, it can flow several hundred kilometers before it cools enough to freeze. This creates a long stretch, or reach, of open water. The upstream edge of the ice cover may be thin or unstable due to fluctuations in discharge. The frozen river may be a significant roadway for men and animals, and river crossings may be frequent. An open reach can disrupt migratory routes, river crossings, and winter travel on the river in general. Open water exposed to very cold air produces ice fog which can blanket a large area and create hazardous driving conditions. An open reach might encourage frazil ice production causing problems for other facilities downstream. It may be necessary to build bridges to allow river crossings over open reaches or to put up signs warning of thin ice. There are no known effective methods of controlling ice fog. However, the length of the open reach can be decreased with the use of ice booms or by changing the topography of the river bed to decrease water velocity. Controlled discharge can be used to stabilize the upstream edge of the ice cover. Manitoba Hydro Columbia River Ice fog increases due to open water British Columbia, Canada reaches on the Columbia River are expected to be about 5%. Equipment or Structures Damaged by Ice in Any Way The hydropower plants listed here are those that responded affirmatively to the statement "Equipment or structures damaged by ice in any way" on a questionnaire. The nature of the damage is unknown to us at this time. Annex Creek Alaska 2.8 MW Pidgeon River Plant The problem is minor. Vanderbilt, Michigan '11-100 kW Forces Motrices de Mauvoisin Switzerland 3 plants 835 million kWh Hnchor Ice Anchor ice forms on fixed objects such as the stream bed or manmade structures. It can block intakes or restrict flow in a channel. An insulating ice cover or heated structures can decrease anchor ice formation. Sometimes it is manually chopped out. Sheldon -Jackson Junior College Ice in a 2000 foot flume must be Sitka, Alaska manually chopped out. 50 kW Bruce P. Sloat Anchor ice has blocked intake Lancaster, N.H. structures. 15 kW Reservoir Ice Problems Changing water levels in a reservoir cause the ice cover to move up and down. This can damage structures, particularly dams. Also, as the water level drops, the center of the ice cover may sag giving the ice a slope that is dangerous for men and animals. Structures exposed to the ice must be made sturdy enough to withstand its abuse. Warning signs and fences may be needed to keep people and animals away from dangerous ice cover. Upper Salmon Creek Alaska 2.8 MW Crystal Lake Petersburg, Alaska Ice several feet thick rubbing against the upper face of the dam. Minor damage to the dam. The problem was solved with aluminum facing. Other Problems with Ice Annex Creek Icing of transmission line conductors. Alaska 2.8 MW Dewey Lakes Water seeps under the earth dam creating Skagway, Alaska a glacier on the creek bed below the 30-375 kW dam and threatening penstocks that come out of the dam. Snettisham Icing on transmission line destroyed Juneau, Alaska the line APPENDIX 2 RESULTS OF QUESTIONNAIRE STUDY OF 28 BRITISH COLUMBIA HYDROELECTRIC STATIONS Report to the State of Alaska, Department of Commerce and Economic Development compiled by T. E. Osterkamp Greg Penn J. P. Gosink Geophysical Institute University of Alaska Fairbanks, Alaska 99701 BRITISH COLUMBIA HYDRO AND POWER AUTHORITY BOX ,212, $55 WEST HASTINGS STREET, VANCOUVER, B-C. V68 4T6 CABLE ADDRESS "INTERPOW" TELEX 04-54456 December 14, 1981 File: 1206.10 Mr. T. Osterkamp, Professor of Physics, Geophysical Institute, C.T. Elvey Bldg., University of Alaska, Fairbanks, Alaska, 99701, U.S.A. Dear Sir, This is in reply to your letter dated nil to our Peace Canyon Project, which was referred to me. Enclosed are a reference map and completed ice questionaires for 28 B.C. Hydro hydroelectric generation stations. All but two of the plants responded and, at those two, ice problems are not usually experienced. The capacity of both unreported plants exceeds 1000KW. We would appreciate receiving copies of your survey results. We request, if possible, six copies for distribution to our region managers who completed the questionaires. Yours very truly, G.M. Salmon TPK/rt Manager, Encls. Development Department Please complete this questionnaire and return it in.the envolope. provided. Write the name and complete mailing address of your facility in the space below. Name of facility: C4 C- Ll l c.-» F� Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW_ 11-100 kW_ 101-1000 kW V� more than 1000 kW Have you had any difficulties with ice? Yes ✓ No If not, mail this questionnaire without continuing. _ Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice................i/ Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray.... .......... -- Equipment or structures damaged by iceinany way._ Other. Please specify. f._ I �• y r r� l7-n n` 1 n 11i J-71 i t C 1 _ Thank you for your cooperation. 702 W Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. . liame of facility: 8Vt3'f'.:&l5r� ..Put a mark next to the appropriate response. -The capacity of our facility is: 0-10 kW 11-100 kW�J 101-1000 kW more than 1000 kW Have you had any difficulties with ice? Yes No 1/ If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray.................. ... Equipment or structures damaged by ice in any way._ Other. Please specify. Thank you for your cooperation. s,— 0._1 2 'L I oo M �J Geophysical iratiww. C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 h10NE-907479.7282 TELEX: 35414GEOPH INSTSBK L Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Yams of facility: ALOC'rrIl Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW-/— $loco k-VJ Have you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. _ Icing of structures from spray .................... - - Equipment or structures damaged by ice in any way._ Other. Please specify. Thank you for your cooperation. G:-OP')':z-` I:-sunrtr, C.L Elvey Building, University of Alaska, Fairbanks, Alaska 99701 . PH0r:E_ PQ7-479-72&2 TELEX: 2514 GEOPH MST SBK e Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. . Mame of facility: G.M. Shrum Generating Station Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW XX Have you had any difficulties with ice? Yes X. No_ If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................— Flooding caused by ice jams, hanging dams, etc. .. X Icing of structures from spray .................... Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. 2.416CDO 6N! sus Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Name. Of facility, Peace Canyon Generating Station 1 _ Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW .11-100 kW 101-1000 kW�A more than 1000 kW_✓ `M00Cp k 4 Have you had any difficulties with ice? Yes X. No If not, mail this questionnaire without continuing. — Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ — Flooding caused by ice jams, hanging dams, etc._.:-X' Icing of structures from spray........ — - Equipment or structures damaged by ice in any. Other. Please specify. — Thank you for your cooperation. Please complete this questionnaire and return it in the envolope provided. - Write the name and complete mailing address of your facility in the space below. Name of facility: 10e1Jr 1'AJ e5• �• Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW— 101-1000 kW more than 1000 kW X �o5�boo k,u} Have you had any difficulti2s with ice? Yes No X If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. _ Icing of structures.from spray .................... — — Equipment or structures damaged by ice in any way. — Other. Please specify. Thank you for your cooperation. G ps ysio; Institute, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 PHONE: 907A747262 TELEX: 3iS16 GEOPH INST SSK .1 Please complete this questionnaire and return it in the envolope provided. _ Write the name and complete mailing address of your facility in the space below. Xame of facility; vtE rf}"S C7• S. Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW_ 101-1000 kW more than 1000 kW_,>Z 5215eD LW Have you had any difficulties with ice? Yes No. If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ — Flooding caused by ice jams, hanging dams, etc... Icing of structures.from spray.:..................® Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. G :, .i•a' Insttuti, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 . PHOUL, 907-074778:2 TELEX- IS414 GEOPH INKT SRK Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. dame of facility: �/��//�/7 �• Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW_ 101-1000 kW more than 1000 kW_Z Have you had any difficulties with i.ce? Yes No X If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................®_ Flooding caused by ice jams, hanging dams, etc... Icingof structures.from spray .................... Equipment or structures damaged by ice in any way._ Other. Please specify. Thank you for your cooperation. 601000 kul Geopt:ysia1 Institu-te, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 . PHONF- 4:7<7471F TFI FY• 19 14 nFrIPN IllC fMe M Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Name of facility: Put a mark next to the appropriate response. The capacity of our facility is: / 0-10 kW 11-100 kW101-1000 kW more than 1000 kW V Have you had any difficulties with ice? Yes—V No_ If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray .................... Equipment or structures damaged by ice in any way. te- Other. Please specify. - T V � 'u..e \9- d up 414^&4 I: � ..post c Lo_� OLJLl, Q C-d:(, w.Qw1 ia��a ._ Carp—" � n ba, G{A J- 4t, i c Thank you for yoUr cooperation. Geophysical Institute, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 P Mllu c-any wee ��m ru cv. w... ncnnu we-r c.... S Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. / Name of facility: ,L0- Toi< d'a„I„/Z4-r.' c S747T,ae/ Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW_ 11-100 kW 101-1000 kW • more than 1000 kW ✓ 22fOf,0 �c� Have you had any difficulties with ice? Yes ✓ No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter...® Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. Icing of structures from spray .................... Equipment or structures damaged by ice in any way. Other. Please specify. 1 Thank you for your cooperation. Geophysical Institute, C.T. Eivey Building, University of Alaska, Fairbanks, Alaska 99701 PHONE: 907-479"7282 TELEX: 35414 GEOPH INST SSK Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below, Name of facility; i3,Q7a6c 21 ✓cZ CZ14x447-,,µ%G ST,a%oq/ % Put,a mark next_to the appropriate response. The capacity of our facility is: B # 0-10 kW_ 11-100 kW_ 101-1000 kW more than 1000 kW 2. = �w Have you had any difficulties with ice? Yes / No 928,E If not, mail this questionnaire without continuing. _ Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ — Flooding caused by ice jams, hanging dams, etc. — Icing of structures from spray .................... Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. Geophysical Institute, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 PHONE: 907A79-7282 TELEX:35414 GEOPH INST SSK M Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Name of facility:,c= -el ✓ic%L G'c4/G-,-A%/,,J 5%A71Osc/ 0'L Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW Have you had any difficulties with ice? Yes No nu If not, mail this questionnaire without contiing. _ Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray.. ... ........ Equipment or structures damaged by ice in any way. Other. Please specify. -- of-ah, U. Y Thank you for your cooperation. 'B1+Z = 42,8/000lc0 Geophysical Institute, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 PHONE: 907479-7282 TELEX: 35414 GEOPH INST SSK Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. . Mame of facility: Put.a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW_ 101-1000 kW more than 1000 kW '� 42,000 Have you had any difficulties with ice? Yes No_✓. If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open °:rater downstream of the facility in winter..._ Intake structures blocked with ice ................ - - Flooding caused by ice jams, hanging dams, etc... _ Icing of structures from spray.....................o Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. Geo-tlysical lrst;tvte, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 PHOt:E907479-72S2 TELEX: 35414 GEOPH INSTSBK Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. lame of facility: Put a mark next to the appropriate response. The capacity of our facility is: _ 0-10 kW 11-100 kW 101-1000 kW_ more than 1000 kwo o �•v Have you had any difficulties with ice? Yes No ./ If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. _ Open water downstream of the facility in winter... Intake structures blocked with ice ...... ......... Flooding caused by ice jams, hanging dams, etc. Icing of structures from spray:,:. Equipment or structures damaged by ice in any Other. Please specify. Thank you for your cooperation. M Please complete this questionnaire and return it in -the envolope provided. Write the name and complete mailing address of your facility in the space below. . Elam® of facility: 962rr/o1.'e 67Ze w� Put a mark next to the appropriate response. The capacity of our facility is: - 0-10 kW 11-100 kW 101-1000 kW_ more than 1000 kW_, Have you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice... .............. Flooding caused by ice jams, hanging dams, etc. _ Icing of structures from spray.................—• Equipment or structures damaged by ice in any way,® _ Other. Please specify. Thank you for your cooperation. G�ophysid inst njtt, C.T, Elvey Building, University of Alaska, Fairbanks, Alaska 99701v A— P"0NE907479-72S2 TELEX: 35414GEOPH INSTSSK Please complete this quesnare anhe tionid returnAt in:t provided:- '= • _ _ - _ - >J!•-r. s . •-_�� �T.d�\:-°n••' �i'JC _•�`••'•"p�i .. � •. -•: a-=^_ � •TY'"TT+t' _ :.eTf+! a: r _ Write the name and complete mailing address of your facility in the space below. = _- Name.of ficlIIty.- . • Put -a mark next. to the appropriate_ response.-`_ The capacity'of our facility isi.r` ^'- -= _ -: =- ° z:.;r:: ' .'•.� ; - 0-10 kW_ 101-10001V ' more than IOOO kW Have -you had any difficulties* with ice? Yes Ho_'•- If not, mail this questionnaire without continuing: - Put a mark next to problems associated with ice'and cold climate that have occurred at your facility.- _ Open water downstream of the facility in winter... Intake structures blocked with ice.>..._:�..:.:.<.— Flooding caused by ice jams, hanging dams, etc:'.— _- Icing of structures from .- Equipment or structures damaged by_ ice in any way._: - Other. Please specify. Thank you for your cooperation. ' `"= • - ".��' •a;',•i • r ::. =:..: �S -. 1.1,E ._�"� �� : :��a�r_ r _T-::_y �� :i . _ S - _ •'` _ 1 • �t f:�. �. ••%E'er •%L. 1 ,•.• • _r.i �+•�iT• •• /T ..' t..:.. -mow. ':�: «.. -... -_ ="; �••7 •y:._ C.T. Elrry Huldrg, Unirersitof Alaska, Fairbank%Alaska 99707 _ =• `.:'�-,. _-� r�• `��.s^; �-.�•,;,J� ft*NLi07.47P7= TELEJ:2U1/GEOPHINSTS7K5CS'�-�-:iiM�*-:i , V. �� +�`• +i7r�.r•.�:.33.�rs�i •s !!'R_•il-'a:L'LX'f�isf�.ri y+�.z'-.yam:.-:-,2� �:.2.�.:.1':ix. .:t-_z-�-..,, .-_ � _ .� Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. liame 'of facility: Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW_ 11-I00 kW_ 301-1000 kW_ more than 1000 kW 007)$"00 40 Have you had any difficulties with ice? Yes No­� If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray .................... Equipment or structures damaged by ice in any way._ Other. Please specify'. Thank you for your cooperation. Geofiysial 4nstituty, CT. Elvey Building, University of Alaska, Fairbanks, Alaska'99701 PHONE °07A79-7262 TELEX: 35414 GEOPH INSTSSK _ _, M Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Name of facility: C L /:V ej .a .S7s r: :- +. Put a mark next to the appropriate response. The capacity of our facility is: - 0-10 kW 11-100 kW_ 101-1000 kW_ more than 1000 kW Have you had any difficulties'with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter,.. Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc... v Icing of structures from spray._..:.. Equipment or structures damaged by ice in any way.® Other. Please specify. Thank you for your cooperation. Cxophysicsl itutit:.v, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 PHONE 907<79-77R7 TFI cv• vu.e renew �.�� _ .- E G Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Hame of facility- IAQ5 W 64Q Put a mark next to the appropriate response. The capacity of our facility is: - 0-10 kW_' 11-100 kW 101-1000 kW more than 1000 kW Have'you had any difficulties with ice? Yes ,/ No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. - Open water downstream of the facility in winter... Intake structures blocked with ice ................. Flooding caused by ice jams, hanging dams, etc. . Icing of structures from spray.. t....... .=/ Equipment or structures damaged by ice in�any�way. Other. Please specify. Thank you for your cooperation. Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. lame of facility: k,.)F�ATS l�� CI�NEi�ATINC� S�L1TtZ,/J l Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW .11-100 kW_!d- 101-1000 kW more than 1000 kW_� Have you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice ....... Flooding caused by ice jams, hanging dams, etc. . --- Icing of structures .from spray.... ....::.....:.... Equipment or structures damaged by ice in any way. . Other. Please specify. — Thank you for your cooperation. Geophysical In -juju. C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 _ _ . PHONE-907479-7282 TELEX. 35414 GEOPH INST SSK -�1���74Y y a ii MR, k AM Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. lame of facility: Wo�`�rer ��c �v.a�. Cle-,, — Cg000 }Zw� Put a mark next to the appropriate response. The capacity of our facility is: - 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW Have you had any difficulties with ice? Yes / No If not, mail this questionnaire without continuing. _ Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ............... Flooding caused by ice jams, hanging dams, etc. Icing of structures from spray .....a.... .. Equipment or structures damaged by ice in. way.® Other. Please specify. Thank you for your cooperation. Please complete this questionnaire provided, d return it in the envolope Write the name and complete mailing address of your facility in the space below. iw-m- of facility: J 0 06 f1 N G Eft' !«V 6 is Put a mark next to the appropriate response. ` The capacity of our facility is _ / 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW ✓ Have you had any difficulties with ice? Us No If not, mail this questionnaire without contTnuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. 150d000 k—w Open water downstream of the facility in winter... Intake structures blocked with ice ................ Flooding caused by ice Jams, hanging dams, etc. _ Icing of structures from spray.; ........... ­ - * pray.:.............:. Equipment or structures damaged by. ice in any way.=---�-14o-t�t,t�vy CotVc U A Vr=-- Other. Please specify.' Thank you for your cooperation. ft Please complete this questionna ' and return it in the envolope provided. Write the name and complete calling address of your facility in the space below. i pane or teciiitys- = A`, 94 4r? " Put a mark next to the appropriate -response. = Thc-capacfty of our fact ity�is• - 0-20 kW 11 100 kW ` 101 1000 kW�more than 1000akW :.' Have' -you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ...............:_ Flooding caused by ice jams, hanging dams, etc. . _ Icing of structures from spray ...................._ Equipment or structures damaged by ice in any way, Other. Please specify._ Thank you for your cooperation. r 2512-00 kv\ 6yL."S s,4o,.-7 Ga0%n S'0 //-0/%Yy r0/s9f<'✓gas a/S 0 6i i--L".leC-d 9K"/1� /o rQ i` t < O ry R�/ •` ✓ ¢ w 0I'177s L _ g t af3 Q l- �1fr c,__�iyt_Co�4c YaI✓4 G*op yicil instibrce C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 _ M40NE907-479-7282 TELEX:35414GE0PHIN57SBK Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. ` Same of facility: 1,cz�. Put a mark next to the appropriate response. -The capacity of our faci1' y is: 0-10 kW 11-100 kW 101-1000 kW_ more than 1000 kW V/. 27"'o k'J Have you had any difficulties with ice? Yes No 1/00 If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. - Open water downstream of the facility in winter... Intake structures blocked with ice ................—` Flooding caused by ice jams, hanging dams, etc. Icing of structures from spray ......... ....... .... — Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. ' __" —. • may. - - -_ _ _ ... • n = � .J . 1 �. 3' -`' _ _ -` _ lam' _TGwphys dl 1nstiLrta, C.T. Elvey Building, University of Alaska, Fairbanks, Alaska 99701 _ • - _ • -' _ • _t rHONEc D07479-7282 TELEX: 3S414 GEOPH INST SBK Please complete this questionnaire and return it in the envolope provided. _ Write the name and complete mailing address of your facility in the space below. p Mame of facility: _ Put'a mark next to the appropriate response. The capacity of our faciljy is: 0-10 kW .11-100 kW V4 _ 101-1000 kW more than 1000 kW_�. (01 SCO �-) Have you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have Occurred at your facility. - Open water downstream of the facility in winter..._ Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. Icing of structures from spray .................... Equipment or structures damaged by ice in any way. Other. Please specify. Thank you for your cooperation. Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. ` iame of facility: Put a mark next to the appropriate response. The capacity of our fa c M is: 0-10 kW_ .11-100 kG1101-1000 kW_ more than 1000 kW_ Have you had any difficulties with ice? Yes No r� If not, mail this questionnaire without continuing. ' Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................® Flooding caused by ice jams, hanging dams, etc. �. Icing of structures from spray.. ................. . Equipment or structures damaged by ice in any way.® Other. Please specify. Thank you for your cooperation. 54)000 V-W Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. �f ia:ne of facility: - Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW .11-100 kW 101-1000 kWmore than 1000 kW ✓ 120� 000 LW Have you had any difficulties with ice? Yes No If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter..._ Intake structures blocked with ice ................ Flooding caused by ice jams, hanging_dams, etc... Icing of structures from spray .................. _ Equipment or structures damaged by ice in any way.® Other. Please specify. Thank you for your cooperation. Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below.; lame of facility: Put a mark next to the appropriate response. The capac�y of our facility is: 0-10 kW_ 11-100 kW_ 101-10.00 kW_ more than 1000 kW_I/ Have you had any difficulties with ice? Yes ✓ No If not, mail this questionnaire without continuing. _ Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Cj) (goo kVJ Open water downstream of the facility in winter... Intake structures blocked with ice ................ F-rnZ l sc�- Flooding caused by ice jams, hanging dams, etc..._ Icing of structures.from spray ...:...........:.... _ y Equipment or structures damaged by ice in any way. — Other. Please specify. Please complete this questionnaire and return it in the envolope provided. Write the name and complete mailing address of your facility in the space below. Name of facility:/ 5 i, w.. n i } (1 Put a mark next to the appropriate response. The capacity of our facility is: 0-10 kW 11-100 kW 101-1000 kW more than 1000 kW ✓ . l32 Have you had any difficulties with ice? Yes No-C If not, mail this questionnaire without continuing. Put a mark next to problems associated with ice and cold climate that have occurred at your facility. Open water downstream of the facility in winter... Intake structures blocked with ice ................ Flooding caused by ice jams, hanging dams, etc. Icing ofstructuresfrom spray.... Equipment or structures damaged by ice in any way. -- Other. Please specify., Thank you for your -cooperation. APPENDIX 3 ICE PROBLEMS AT SWEDISH HYDROELECTRIC POWER PLANTS by Lennart Billfalk an informal translation by the Geophysical Institute Report to the State of Alaska, Department of Commerce and Economic Development ICE PROBLEMS AT SWEDISH HYDROELECTRIC POWER PLANTS by Lennart Billfalk Hydraulics Laboratory Swedish State Power Board Alvkarleby, Sweden ABSTRACT In the following report, a summary of ice problems in hydropower plants in Swedish rivers is presented. The rivers from Lagan in the south, up to Lule river in the north, are included. The information has been collected by the Hydraulics Laboratory, by sending out questionnaires on two different occasions (1977 and 1973), both to the managers of the power plants, and to private companies. Mainly, four types of ice problems can be distinguished: (1) Ice pressure against dams and gates, and freezing -up of gates and blades, in the construction, because of ice build-up, (2) ice formation on intake gates, blades, or turbines, (3) ice floe and slush against the intakes, and (4) ice dams. As far as gates are concerned, the Power Board, in the beginning of the 40's, decided to have effective heating methods to be drawn up to guarantee the maneuverability. There has been further development in improving the safety of running the movable parts of the structures. In order to avoid ice pressure against the dams and gates, a small opening in the ice cover has been made in front of these constructions. The use of current generators, foot -lights, and, in certain sites, air bubblers has shown that nowadays it should not be any technical impossibility to eliminate ice pressure risks that affect sensitive structures. As far as ice forming is concerned it seems to be that the heating of intake gates usually results in lessening the problems, but ice forming can start in spite of the installed gate warmers. The effect that has been brought about by heating the iron of the gates is self- ` evident, but it seems to be difficult to eliminate entirely the risk of ice formation at certain stations. The only way to surely avoid icing problems is to bring about a fast and lasting freeze-up upstream of the station. Problems with ice floes and slush affecting the intake and the origin of ice dams are partly connected to how the power stations are regulated. Short term regulating, when there is a great difference between the daytime and nighttime use of water, increases the risk for this type of ice problem (even icing -becomes greater since the freeze-up has been made more difficult). In the following report (part 1), the description of ice problems, and the measures to prevent troubles are summed up and commented upon. The report has been based on the information submitted by administrators and power companies. The part 2 of the report is made up of a combination of the letters that were obtained in answer to the questionnaire that was the first one to be sent out in 1977. Finally it is noted that information about ice problems (information was obtained from the first questionnaire in 1977) was summed up as a contribution to IAHR's ice symposium in Lulea in 1978 [5]. 1 INTRODUCTION In the year 1937, the general director of the State Power Board gave C. E. Soderbaum an assignment to work systematically at questions that were connected with ice difficulties of hydraulic power plants. In the presence of a threat of a war, there were questions concerning the maneuverability of the gates, and after a study trip during the month of March, Soderbaum and Witalis compiled a report: "Ice problems at hydro power plants(1)". To sum up, it is stated in (1): "There is a need for greater safety against ice difficulties that the power stations have been facing as the technology has been developing. Thus, the gates, where icing can be feared to occur, are fitted with effective warming systems. When it it necessary, there are many different ways to protect buildings against ice pressure. In some waterfalls, the results have been satisfactory, but at this point a further development seems to be desirable. As far as mobile constructions are concerned, methods with fully proven effectiveness have been used, and as such, make it possible to have the gates constantly operating even during winter." Finally it is noted in the report (1) that "Proposal has been submitted that current (generators) and other underwater pumps with piping should be installed at several different power stations. By means of underwater pumps, the water is made to circulate and thereby ice build up is hindered. In the year 1959, the director of the Hydraulic Laboratory, Stig Angelin, urged the administrators at the hydro sites to compile various experiences that they have gained as far as many kinds of ice problems are concerned. Part of these experiences compiled, because of the request, were presented in an ice meeting held in connection with the