Loading...
HomeMy WebLinkAboutHumpback Creek Hydroelectric 2006CORDOVA ELECTRIC COOPERATIVE,INC. P.O.Box 20 *705 Second Street *Cordova,Alaska 99574-0020 *(907)424-5555 *Fax (907)424-5527 March 29,2006 APR G 3 2006 Mr.David Lockard AIREAJ AEAAIDEA/AEA 813 West Northern Lights Boulevard Anchorage AK 99503 Dear David: Attached is the information we forwarded to Karen Larsen at the Rural Utility Service. Please note that you received the PN&D attachments in a recent e-mail from me. However,the total estimate for the project is $1,771,800.00.This total reflects the estimate from PN&D of $1,644,800.00 plus $127,000.00 of CEC's portion of expenses relating to Project Management and Inspection,Environmental Consulting and Administration costs. If you have any questions,please contact me. Sincerel epneth J.Gates Chief Executive Officer Attachment CORDOVA ELECTRIC COOPERATIVE,INC. P.O.Box 20 *705 Second Street *ve (eE We 907)424-5555 *Fax (907)424-5527March29,2006 APR 0 3 2006 AIDEA/AEA Karen L.Larsen Office of the Assistant Administrator Electric Program Rural Development Utilities Programs Room 5165-S,Mail Stop 1560 1400 Independence Avenue S.W. Washington DC 20250-1560 Re:High Energy Cost Grant for Humpback Creek Dear Karen: In reply to your e-mail dated March 22,2006 attached is a revised project budget and a revised SF 242C accompanied by an updated narrative. If any additional information is needed,please do not hesitate to contact me. Sincerely, K#nneth J!Gates ief Executive Officer Vic Enclosures c.c David Lockard,AIDEA Kathy Prentki,Denali Commission UPDATED PROJECT OVERVIEW Project Design Our existing Humpback Creek Hydroelectric facility has been in operation for thirteen years and is in need of structural repair.The plant generates approximately eight percent of Cordova's energy needs.The intake structure screen system is marginally functional due to the amount of leaves,debris and bed load movement.The existing gate system needs to redirect bed load and debris away from the intake and screen and little can be done to improve this problem without modifying the existing gate system or designing and installing a completely new intake structure system.The timber spillway is in poor condition and in need of immediate repair work,and there are signs of severe erosion and gabion damage.The attached report from Petrovich,Nottingham and Drage (PN&D) dated March 25,2004 (inspected in December 2003)illustrates the condition of the project (Attachment D). The work to be completed in the forebay area will allow more consistent volumes of stream flow to be utilized in power generation,reducing the need to burn fossil fuels. Several significant and costly changes have occurred since the last report.In the last several months earth and slope instability adjacent to the wood flume structure has occurred, putting this structure in jeopardy of collapsing.There are additional failures of gabion baskets on the right stream bank that have occurred since the 2003 inspection.Attached is the report from PN&D dated February 27,2006 from their site visit of February 24,2006 that details the updated conditions. In the March 24,2006 report PN&D recommends an assessment for cost estimates for rock scaling,blasting and rock bolting to stabilize the earth and rock surrounding the project structures.Based on the field review scaling,rock bolting and limited blasting will be required both before the bridge and after the bridge in several areas.The general course of construction will require initial tree clearing,overburden removal in areas and rock scaling to remove lose rock from the slope that vary from 15 to 50 feet in height.The need to perform rock blasting will be assessed upon completion of the rock scaling.In addition, the existing wood flume and intake structure will be demolished and a pile or micropile supported penstock will be installed.The penstock would be supported both vertically and laterally with ties to bedrock.This will provide a much more suitable system than the current wood flume and gabion protection system.The addition of the pile supported penstock and intake structure a geophysical survey needs to be completed.See the attached Updated Cost Estimate dated March 24,2006 for details. Project Management In January 2002,the Power Creek Hydroelectric project came on-line for commercial power generation.CEC initiated the permitting and prepared the request for proposals for bidding the construction of the Power Creek Project.The CEC Board of Directors voted to have this project completed on a turn-key basis and entered into a contractual agreement with the winning bidder to construct the Power Creek Hydroelectric Project.The General Manager/CEO of Cordova Electric was instrumental in working with the regulatory agencies,including FERC,Alaska Department of Fish and Game,Corp of Engineers, USDA Forest Service and State of Alaska Department of Natural Resources to secure the necessary permitting and ensure that the permitting conditions were carried out by the contractor.Additionally,the Board of Directors and management contracted with an outside engineering firm to perform quality inspections and project management in coordination with the CEO/General Manager of Cordova Electric. The proposed repairs to the Humpback Creek project are not near the complexity of building a hydroelectric project from start to finish.CEC plans to hire a project manager who will also perform quality inspections during the time that the project is under way. PRELIMINARY COST ESTIMATE FOR REPAIRS HUMPBACK CREEK HYDROELECTRIC FACILITY CORDOVA ELECTRIC COOPERATIVE,INC. Diversion Weir Repairs Intake Gate Structure Repairs Wood Flume Repairs Alternate Pile Supported Penstock Shotcrete Gabions in Channel Erosion Repairs Log Crib Dam Repairs Penstock Wood Cradles Replacement Mobilization/Demobilization Design Fees Additional Items Rock stability blasting,scaling,bolting New intake &gates for flume/penstock Geophysical Fees Sub Total Construction Bidding &Inspection Project Management &Inspection (CEC portion) Environmental Consulting (CEC portion) Administration (CEC portion) Adjustment due to CPI increase over two year period (time from inspection to projected wrk start) Updated 3/29/06 Original Submission 121,772.44 11,834.06 119,956.50 307,685.47 5,917.03 68,874.21 80,944.95 108,015.34 65,000.00 890,000.00 35,000.00 51,925.00 12,000.00 20,000.00 59,100.00 1,068,025.00 Additions 7,227.56 13,165.94 (119,956.50) 545,000.00 (307,685.47) (917.03) 4,125.79 5,555.05 (16,015.34) 40,000.00 536,400.00 30,000.00 17,900.00 754,800.00 (35,000.00) 43,075.00 (59,100.00) 703,775.00 Revised Submission 129,000.00 25,000.00 545,000.00 5,000.00 73,000.00 86,500.00 92,000.00 105,000.00 536,400.00 30,000.00 17,900.00 1,644,800.00 95,000.00 12,000.00 20,000.00 1,771,800.00 OMB Approval No.0348-0041 BUDGET INFORMATION -Construction Programs NOTE.Certain Federal assistance programs require additional computations to arrive at the Federal share of project costs eligible for participation.\f such is the case,you will be notified. COST CLASSIFICATION a.Total Cost ;b.Costs Not Allowable c.Total Allowable Costs for Participation .(Columns a-b) 1.Administrative and legal expenses $20,000 00 |$00 |$20,000 -.00 2.Land,structures,rights-of-way,appraisals,etc.$00 |$00 1%.00 3.Relocation expenses and payments $00 {$.00 {$:.00 4.Architectural and engineering fees $105,000 90 |$00 |$105,000 _-00 5.Other architectural and engineering fees $00 1$00 |$.00 6.Project inspection fees $95.000 00 1$.00 {$95,000 .00 7.Site work $554,300.00 1$00 {$554,300 .00 8.Demolition and removal $00 {$.00 |$.00 9.Construction $997,500 00 |$00 |$997,500 .00 10.Equipment $00 |$00 |$.00 11.Miscellaneous $00 |$00 |$.00 12.SUBTOTAL (sumoflines 1-41)$1,771,800 00 |$00 |$1,771,800 00 13.Contingencies $00 {$00 {$_.00 14.SUBTOTAL $1,771,800 00 1$00 |$1,771,000 00 15.Project (program)income $00 1$00 |$-00 16.TOTAL PROJECT COSTS (subtract#15 from #44)$\5771,800 -00 |$00 |$1,771,800 .00 FEDERAL FUNDING ] 17.Federal assistance requested,calculate as follows: Arter the resulting Pederal shave percentage share.)Enter eligible costs from line 16c MultiplyX_--%$00 Previous Edition Usable Authorized for Local Reproduction Standard Form 424C (Rev.7-97) Prescribed by OMB Circular A-102 ||@Incorporated srerezas MEMORANDUMENGINEERS To:Mr.Danny Ackmann Date:Match 24,2006 Cordova Electric Cooperative Project No:054067.01 Ce: From:Mike Hartley,P.E. Subject:Humpback Creek Dam Updated Cost Estimate Danny, PND tecently provided you with an assessment of site conditions based on a site visit on February 24,2006.We recommended at that time that Pacific Blasting be contacted to obtain additional construction cost estimates for rock scaling,blasting and rock bolting.Representatives from Pacific Blasting and Wallace Technical Blasting visited the site with PND personnel and CEC personnel on March 14,2006. Their revised rock stability costs were slightly higher than originally provided. Additionally PND further evaluated the scour potential of the gabion baskets in the creek that provide protection for the wood flume.Based on these additional assessments and discussions with CEC ersonnel we are modifying the work effort to cover several items mentioned in our February 2006 letterPp4aty to you: 1.A more definitive estimate of rock blasting,rock scaling and rock bolting was provided along with costs for helicopter support for the project by Pacific Blasting. 2.PND was requested to evaluate other options for support and replacement of the wood flume structure.:: Revisions to our February 2006 letter are described below. Rock Stability Improvements Based on this field review scaling,rock bolting and limited blasting will be required both before the bridge and after the bridge in several areas.The exact work requirements cannot be provided at this time.The general course of construction will require initial tree clearing,overburden removal in areas and rock scaling to remove loose rock from the slopes that vary from 15 to 50 feet in height.Upon completion of these activities the need to perform any rock blasting will be assessed.Limited rock blasting,if necessary would then be conducted.Following these activities rock bolting would be conducted.The location of rock bolts would need to be field determined.Pacific Blasting and Wallace Technical Blasting will mobilize the necessary crew and supplies to the site to conduct the construction operations necessary to stabilize the slopes on each side of the existing bridge mentioned in our previous memotandum to you. The Contractor will ship 40-foot-long rod stock totaling 640 feet in length to the site and these will be cut to fit the necessary dimensions required to bolt unstable rock slabs.Rock bolting will likely consist of a series of bolts with possible ring ties if needed to provide the necessary compression and stabilization of the slope. 811 FIRST AVENUE,SUITE 570 *SEATTLE,WASHINGTON 98104 ¢phone:206.624.1387 ©fax:206.624.1388 Page 2 of 2 Match 24,2006 Humpback Creek Dam Updated Cost Estimate Pile-Supported Penstock Improvements PND was asked to consider other options to the creek slope stabilization that involved shotcrete placement on existing gabion baskets.After discussions with CEC it was proposed to demolish the existing wood flume and wood flume intake structure and instead install a pile or micropile supported penstock.The penstock would be supported both vertically and laterally with ties to bedrock.The advantage of this system is it is not dependent on the gabions to survive a flood event.Gabions,even when shotcreted,will eventually scour and fail at some time in the future.This system would not be dependent on scour and therefore will result in much longer design life for the project.Installation of a pile-supported intake structure with new concrete,penstock gate valve and diversion gate valve will provide a much more suitable system than the current wood flume and gabion protection system.PND has included the additional costs for construction and design of this system in the revised cost estimate and deleted the shotcrete repairs for the gabion face. Permitting Rock blasting and scaling of rock that falls into the creek will require some interaction with permitting agencies.The majority of this work will be performed by another consultant but will require some interaction with PND.It will also be necessary to coordinate with FERC to ensure compliance on modifications to the dam infrastructure. Geophysical Work With the addition of a pile-supported penstock we have added costs to perform a geophysical survey by Apollo Geophysics.A geophysical line will be performed along the existing wood flume and at two locations perpendicular to this line to confirm the approximate location of bedrock in support of design of the pile-supported penstock and pile-supported intake structure design.This work could be performed as soon as April 3,2006. Based on these changes and the more refined estimate of Pacific Blasting the total construction cost from our February 2006 letter has been revised from $1,592,500 to $1,644,800;a $52,000 change.The final cost estimate is detailed in the attached spreadsheet.The changes improve design life for the facility significantly,reduce overall maintenance costs and provide in our opinion a superior design. I am also attaching a copy of our February 27,2006 memorandum.With the exception of the deletion of the shoterete and the work described above the other work elements have not changed.We are also attaching a copy of the Pacific Blasting construction cost estimate to perform this work.Should you have any questions please contact us at your convenience. Sincerely, PND Incorporated hhFZ Milké Hartley,P.E. Vige President Attachments:Original Feb.27,2006 Field Assessment Report March 21,ific Blasting Letter on Rock Slope Stabilization Construction Costs |S|2 REVISED PRELIMINARY COST ESTIMATE FOR REPAIRS Humpback Creek Hydroelectric Facility Comparison of estimates and work scope Cordova,Alaska Original Revised Estimate Construction Item 2004 Price'3/22/2006? Diversion Weir Repairs $102,900 $129,000 Intake Gate Structure $10,000 $25,000 Wood Flume Repairs $104,000 $0 Alternate Pile-Supported Penstock $545,000 Shotcrete Gabions in Channel $260,000 $0 Erosion Repairs $5,000 $5,000 Log Crib Dam Repairs $58,200 $73,000 Penstock Wood Cradles Replacement/Repairs $68,400 $86,500 Mobilization/Demobilization $91,275 $92,000 Design Fees $65,000 $105,000 Construction Inspection Fees $35,000 $0 Total Construction Cost (original items)$799,775 $1,060,500 Additional Items Rock stability blasting,scaling and rock bolting $0 $536,400 New intake and gates for flume/penstock $0 $30,000 Geophysical Fees (Apollo Geophysics)$0 $17,900 Permitting Fees $0 $0 Total Estimated Construction Cost $799,775 $1,644,800 Notes: 1.Column 1 refers to the original estimate provided to CEC 2-1/2 years ago. 2.Column 2 represents a more refined rock slope stability estimate and change in infrastructure repairs as described below. a.Shotcrete of gabions in channel has been deleted and wood flume repairs has been deleted.It has been replaced with wood flume demolition and replacement of this section with a pile-supported penstock anchored to bedrock both vertically and laterally.The advantage of this system is it is not structurally dependent on the gabion baskets that armor the creek.After discussions with CEC this option provides a longer design life and less impact during flood events.It is not dependent on an aging gabion wall system that even if shotcreted could be undermined in future flood events requiring additional repairs.This work also includes necessary geophysical work to determine approximate depth to bedrock in support of the design and additional design costs to accomplish the work. The work would also include a new pile-supported intake structure for the new segment of penstock. b.Costs for rock stability blasting,scaling and rock bolting have been refined by the Contractor in this estimate based on a site visit on March 14,2006 by Pacific Blasting and Wallace Technical blasting.Costs for permitting related to rock scaling,blasting have been added to ensure compliance with permitting agencies. c.All other infrastructure repairs remain the same as described in the original February 27,2006 assessment by PND. Differences shown between the 2004 and 2006 costs account for substantial cost escalation during this period and the reassessment of the condition of each item during a field visit in February 2006--over 2 years since the original estimate was provided.The primary change in scope is the addition of rock stability work;deletion of shotcrete to stabilize gabions and instead installation of a pile-supported penstock replacement. d.Attached to this estimate is the new cost estimate from the Contractor Pacific Blasting for rock stability work. PND Incorporated,Engineering Consultants 811 First Avenue,Suite 570 Seattle,WA 98104 March 24,2006 PACIFIC BLASTING &DEMOLITION LTD. March 21,2006 Peratrovich,Nottingham &Drage Inc Suite 260 811 First Avenue Seattle,WA 98104 Attention:Mr.Mike Hartley Dear Mike: RE:Humpback Creek Hydroelectric Facility -Rock Slope Stabilization for Cordova Electric Cooperative -Cordova,Alaska Pacific Blasting is pleased to supply budgetary numbers for the above project.I have based the budget on the following assumptions: Project area requires 36 (working days)of scaling Rock bolting duration is 15 working days. Total project duration is 51 working days.In actuality,it will probably be substantially less. Equipment Mobilization is by truck transport overland.We are currently investigating cheaper marine alternatives. Equipment and material mobilization to site from Cordova will be by ASTAR-sized helicopter.In order to accommodate this size of helicopter and maintain safe weight restrictions,2 small compressors and an air receiver tank will be required for rock drilling/bolting.The ASTAR is approximately one-half the cost of a Bell 212 helicopter. The costs for each unit are shown below. Rock bolting costs are based on installing 640 lineal feet of rock bolts.Individual rock bolt lengths will be determined in the field and cut from 40-foot anchor stock on site. The standard factory length for Dywidag rock bolts is 40 feet.Sixteen (16)Dywidag anchor bar lengths (40 ft lengths)will be shipped and cut to the required length on site. The rock bolting price also includes 80 -face plates and nuts,and 20 -10”wide by 12 ft long support straps for additional rock support techniques. It is assumed that 6400 Ibs of anchor grout will be required. Blasting,if required will be kept to small shots to control blast vibration and material throw. It is assumed that 3 separate trips will be required for trim blasting by Wallace Technical Services.Each trip will be 3-days in duration,including travel. Project Budget -Breakdown: Based on 51 working days Project Start Up Mob/Demobilization Project Insurance Scaling Labour Rock Bolting Labour Rock Bolt Equipment Compressor Grout Plant Rock Bolt Materials Helicopter ASTAR Crew Boat Cost Crew Travel Time (boat) Blasting (Wallace Technical) Explosives (Wallace Technical) Blast Insurance (Wallace Technical) ESTIMATED TOTAL Additional cost if a Bell 212 helicopter is required TOTAL $1,800.00 $67,200.00 $30,600.00 $131,200.00 $54,700.00 $8,600.00 $11,800.00 $3,000.00 $7,400.00 $46,500.00 $17,600.00 $34,000.00 $18,000.00 $5,000.00 $4,500.00 $441,900.00 $94,500.00 Unit Rate $ 365.00 365.00 57.28 40.00 20.00 334.00 $6,000.00 per crew hour per crew hour per hour per hour per hour per trip Kerry Jager,after visiting the site,estimated that the project will take from 6 to 8 weeks to complete,or 36 to 48 working days.If we can complete the project in 36 working days,the overall costs will be substantially less than the above budget. The blasting budget has been prepared by Wallace Technical Blasting Inc.The actual amount of blasting to be performed will have to be determined in the field,as stabilization work on the face progresses. If you have any questions,please call me at your convenience.Thank you. Yours truly, Pacific Blasting &Demolition Ltd. FL Une Ron Woolf General Manager -Mining Division || Incorporated <u MEMORANDUMENGINEERS Yo:Danny Ackmann Date:February 27,2006 Cordova Electric Cooperauve Project No:054067.01 Ce: From:Mike I lardey,PE. Subject:Field Assessment of Site Conditions for Design Services Danny, Per your request PND visited the Humpback Creck Dam site on February 24,2006.Ithas been over nvo years since the last inspection was performed.The purpose of this inspection was to assess current conditions in support ofproviding design services for the project. Conversations with CEC personnel have indicated that earthen slope instability adjacent to the wood flume structure occurred this last winter.In addition it was indicated that additional failures of gabion baskets on the night stream bank have occurred and some other miscellaneous problems have been noted since our last inspection in 2003,For this reason PND recommended performing an additional field trip in support of preparing a detailed scope of work and cost estimate for performing design services for the project. Several significant and costly changes have occurred since the last report.Many of these changes will result in additional costs to repair the facility from what was estimated in our March 25,2005 letter. 'These are a dircet result of changes in site conditions since our last visit.They are also a result of the escalation in material costs since our estimate was provided..As you are probably aware many material costs increased over 30 percent in the last year and up to 70 percent in the last nwo years.The combination of the site condition changes and material cost increases leads us to believe the previous budget we provided to you should be tnereased or the work elements should be bid on using bid alternates to maintain budget and some items be delayed until funding ts available,if necessary. T would like to briefly discuss the condition of each item we inspected.Our March 25,2005 letter addresses work previously completed and pnoriues for repairs (a copy of this letter is attached for your information).Tam going to address these items in the same order as we originally addressed them in chat letter for comparison purposes.Photos from our trip are attached for your reference. Item 1.Diversion Weir Repairs The timber spillway structure has had additional scour and loss of boards.There was too much water flow to accurately estimate the additional work required,if any.Several more tongue and groove boards have been lost on the top surface of the weir,PND originally estimated $102,900 would be required to perform this work.It is recommended this cost estimate be revised to $129,000,It should also be noted that additional field inspection of timbers will be needed to confirm condition once water flows decrease. Item 2.Wood flume Repairs STP FIRST AWE NUESSUPEE 370 SEVTTEEL WOASTEENGATON 98 104 ©phone:206.624.1387 @ fy.206 624.1388 Pape >ot 5 Feb.27,2G Humpback Creek Dam Licld \ssessment The condition of the wood flume ts similar to that noted in our previous report.[Lowever,several things have occurred that were not neted in our original report: 1.Durning the large storm event this last fall a significant amount of matenal was deposited m the flume that required removal by hand digging material and removing. 2.An earthen slope failure impacted the side of the wood flume.It is likely that continued use of an open-top wood flume could result in material entering the fume structure or damage to the flume structure.We continue to recommend either a umber flume structure or HDPE penstock (similar in size to the exisung penstock)be used at this location.Our primary concern ts the gabion baskets that are used for protection from scour are in much worse condition than during our last inspection where several areas have dropped due to additional stream scour and material loss from the overtopping flume. Costs for this work were originally estimated at $104,000 with material cost increases this is more likely to increase to §135,000 based on the current market conditions. Item 3.Shotcrete Gabions in Channel Additional scour and damage has occurred to gabions with complete loss of some gabions downstream from the wood diversion flume.We previously recommended shortcrete repairs to these gabions ta provide some level of protection.With the loss of some gabions and the setdlement of others it ts estimated the cost of this work will increase from $260,000 to approximately $410,000. Item 4.Penstock Wood Cradles Replacement/Repairs Our recommendations remain unchanged for this portion of the work.All cradles should be replaced. Costs,based on current market conditions,would result in an increase from $68,400 to approximately $86,000. Item 5.Intake Gate Structure Repairs Our recommendations remain unchanged for this portion of the work.However,one change has occurred at the intake screen.New scour has occurred below and along the right abutment of the intake screen.This has been temporarily protected with sand bags.It appears that rock conditions are becoming increasingly poorer at this location.Diversion of water with sand bags and shorcreting will be necessary to repair this area.The combination of this additional work and changes in market bidding conditions will likely increase the cost for this work from $10,000 to $25,000, Item 6.Erosion Repairs Additional erosion was noted at the wooden diversion flume but not on the main flume structure. However,it should be noted that we could not tully inspection the main fume structure due to snow. Our recommendations remain unchanged and costs for this particular item remain unchanged at $5,000. Item 7.Log Crib Dam Material is continuing to be scoured from the base of the log crib dam.Our recommendations remain unchanged.Placement of timbers and lag screws will help contain material within the fog ertb dam. Material costs for timber should be increased from costs noted in our orginal estimate.We recommend increasing costs for this item from $58,200 to $73,000 as a result of changes in market conditions. Other Items Item 8.Stability of Slopes PND did not provide any recommendations for changes to the rock slopes adjacent to the facility in our last report.Significant changes have occurred in the last several vears to rock slopes in this area, ||2 Page 3 of 3 Feb.27,2006 Humpback Creck Dam Pield:\ssessment Condinons noted during our inspection are as follows: a.Rock slope just prior to bridge During our last inspect minor amounts of rock debris were falling trom this slope and the condition of the rock slope itself was fair.The condition has changed significantly.The slope has large blocks of rock that have loosened significantly.These blocks are on the verge of falling and are considered a hazard to personnel and to the penstock.Significantly more work will be required to stabilize this area than budgeted for during our last inspection. b.Rock slopes between the bridge and log crib dam. These slopes were in poor condition before.Additional rock has failed causing damage to hand rails and the walkway.In addition the condition of the rock faces in these areas are showing signs of additional instability. c.Slopes adjacent to flume. A earthen slide has occurred at this location resulting in material impacting the flume.It appears that some material may have entered the flume during this slide. We are not sure of the reason for the significant change in conditions noted from those of two vears ago.The majority of rock fall from Item a.was small in nature (cobble size}.Changes could be due to mechanical freeze-thaw processes,an earthquake or a combination of the two.It now appears that blasting,scaling,rock bolting and mesh may be needed in some areas.For this reason we are recommending Pacific Blasting be contacted to perform an inspection of rock slopes and assess the necessary changes that should occur toimprovesaferyandminimizepotentialfordamagetoinfrastructure.Due to the safety issues we wouldrecommendthisbeperformedimmediatelyandtheadditionalworkrequiredtostabilizeslopestakeahigh priority.Pacific Blastingis also a contractor and can perform the necessary construction work to stabilize conditions noted.PND has been asked to provide an estimate for what this work mav cost to accomplish.It is likely to be on the order of $300,000.However,please note this is an estimate..\more detailed estimate should come from Pacific Blasting once their initial assessment is complete. Item 9.Bridge We did not sce a significant change in the bridge condition except for one item.The bridge is supported by a main strand cable.Loads from the steel truss supporting the penstock are transferred to this main cable through pairs of cables across the bridge.The connector between the main strand cable and supporting cables has rotated approximately 25 degrees counterclockwise when viewed from the left river bank and looking up towards the log crib structure.We are not sure at this point if this is significant or not.It is quite possible that this rotation is a result of the unloading that has occurred since the hydroelectric project is not currently on-line (no water in penstock). This should be inspected again after the hydro facility is back on-line and the penstock is back to full load. The attached spreadsheet summarizes our estimate of costs to perform work at the facility.Design fees and construction inspection fees remain unchanged.Should vou have any questions please contact us at your convenience. Sincerely, PND Incorporated ate and Photos ||b REVISED PRELIMINARY COST ESTIMATE FOR REPAIRS Humpback Creek Hydroelectric Facility Cordova,Alaska Comparison of New Estimate to Previous Estimate Original New Construction Item Price Price Diversion Weir Repairs $102,900 $129,000 Intake Gate Structure $10,000 $25,000 Wood Flume Repairs $104,000 $135,000 Shotcrete Gabions in Channel $260,000 $410,000 Erosion Repairs $5,000 $5,000 Log Crib Dam Repairs $58,200 $73,000 Penstock Wood Cradles Replacement/Repairs $68,400 $86,500 Mobilization/Demobilization $91,275 $92,000 Design Fees $65,000 $72,000 Construction Inspection Fees $35,000 $35,000 Total Construction Cost (origina!items)$799,775 $1,062,500 Additional Items Rock Stability Inspection and Repairs $0 $500,000 New intake and gates for flume/penstock $0 $30,000 Total Estimated Construction Cost $799,775 $1,592,500 Notes: 1.Costs increased based on current market conditions. 2.Costs increased based on changes to infrastructure and site conditions. 3.Costs for rock stability inspection and repairs require confirmation from Pacific Blasting for actual costs.This estimate is a rough,order-of magnitude cost.Inspection of the slopes is required to verify conditions for construction work required. 4.New intake and gates for flume/penstock were not budgeted originally.It is assumed that concrete work will be minimal and piles are not required. PND Incorporated,Engineering Consultants 811 First Avenue,Suite 570 Seattle,WA 98104 February 2006 Humpback Creek Dam Facility Near Cordova,Alaska PND 054067.01 he x Photograph No.1 Description: Additional corrosion around welds on penstock Photograph No.2 Penstock wood cradles are a deteriorating at a faster rate.we ge Steel cradle straps can be re- used. ey feo? eye Tee oo";¥,|Photograph No.3aht 1 eo tareaonea *ty "eG us {Description:Meco.A Ot a 4 Rock slopes are continuing to"»Ne 4 cause damage toarae=]infrastructure.Rock slope inSSelLO"wei upper left (background)isautwe7jalsostartingtoexhibitet_2]increased block failures not--">|found in previous inspection aa aa ;to the degree noted. . . 4 '\.8 so "ye a ee1poeuel8ote we Page |of 4 Humpback Creek Dam Facility Near Cordova,Alaska PND 054067.01 eee oe eeeteee -r €,ae .SaPsionYBe-yaneeareaeSET.Photograph No.4 Description: PND has recommended Pacific Blasting evaluate all rock slopes as part of this work due to the increase in rock instability. Photograph No.5 Description: Flume was difficult to inspect due to snow.However,a earthen slope failure has occutted in the area of the flume that is new. - + %. é'- &3 ° Photograph No.6 Description: Gabion walls are in much worse condition than last inspection from 2004. Page 2 of 4 Humpback Creek Dam Facility PND 054067.01 Near Cordova,Alaska Photograph No.7 Description: Floor of stream has continued to scour the gabions.A new channel has formed on the right where gabions have been completely destroyed. .re|mamas let Fae Oa!Prom :|Photograph No.8 Description: Wooden spillway has lost additional timbers. Additionally a scour hole has formed just downstream from the concrete toe apron approximately 4 feet deep. This scour hole was not present during the last ,|inspection. Photograph No.9 Description: -|Rock has scoured adjacent to"|intake screen (note sandbags). This is a new problem not .|found during the last inspection. ||2 Page 3 of 4 Humpback Creek Dam Facility PND 054067.01 Near Cordova,Alaska Photograph No.10 Description: Closer view of timber spillway. Timber damage is difficult to see with water flow. ||o Page 4 of 4