1 Abstract The use of Review Boards on large hydro projectsis now a common practice. They provide some assurance that theproject layout and design is the optimum for the site. However,some developers are not aware of how Review Boards should beused, and the opportunities provided by the presence of theBoard, to enhance the local engineering experience of both thedeveloper and the consultant. Review Boards are rarely used onsmaller hydro projects, primarily due to cost. However, a strongcase can be made for Review Boards on smaller projects. Thispaper addresses several issues arising from the use of ReviewBoards, including liability, meeting organization and reporting.I ndexTermsHydro, design review, cost, safety.I. INTRODUCTION.There is currently resurgence in the construction of hydropowerfacilities inCanada andaroundthe world. Thisconstructionactivity is straining the resources ofhydroconsultants, to the extent that many are understaffed and theirengineers are overworked. Furthermore, there is a paucity ofsenior hydro engineers due to the lack of hydro activity duringthe dry years between about 1977 and 1997, when fewhydro plants were built.During this period,many hydroengineers either retired or sought employment in other fields.Consequently, there is a risk that design and constructionmistakes will be made due to a lack of knowledgeable seniorhydro engineers at both utilities and consultants. For example,about 15 years ago, the author was asked to review 7 pre-feasibility studies, and four contained serious errors.The risk of errors has been recognized by mostlargeutilities, and is being addressed by the use of Review Boardsconsisting of a few very senior engineers with considerablehydro design and construction experience. Review Boards arenot a new concept; they have been used on many large hydrodevelopments such as Tarbela in Pakistan (1968-76),theColumbia River Storages in British Columbia (1962-73) andat Churchill Falls where the Dyke Boardhas beenincontinuous service since 1969, monitoring safety of the dykesand underground structures.Review Boards are usually cost effective in that they oftenfind errors or improvements that more than cover the Boardexpenses. Also, they provide peace of mind to the owner thatis more valuable than the cost of the Board. However, there isa general perception that they add cost to the development,due to a preference for a more conservative design. This is notalways the case, as the following 2 examples will illustrate -At one utility, it was the practice to encase the turbine steelspiral case with reinforcing bars designed to take the fullJ. L. Gordon is an independent hydropower consultant residing at 102Blvd. St-Jean, Pointe Claire, Quebec, Canada. H9S 4Z1(email: jim-gordon@sympatico.ca).pressure of the water, without any allowance for the steelcasing. Reinforcing bars around the casing are difficult todesign and install, since each one is different due to thechanging shape of the spiral casing. The steel casing was alsodesigned to take the full water pressure without any allowancefor the surrounding concrete. A belt and braces design,mainly to eliminate cracking in the powerhouse substructureconcrete as the steel casing expands under the water pressure.The Board persuaded the utility to undertake a finite elementanalysis of the casing and concrete, and the analysis producedan answer allowing the elimination of about half the steelreinforcing, at a considerable saving in time and cost.Another case involved the addition of anchors to stabilize alarge concrete dam, due to an increase in the reservoir floodlevel. The Board was able to recommend a design wherebyabout half the anchors were eliminated, at a significant savingin cost. So cost savings are possible.Not all utilities are familiar with the use of a Review Board;hence this paper will discuss how, when and why ReviewBoards should be used, and whether Review Boards should beused on smaller hydro developments.II. TIMING OF REVIEW MEETINGS.One of the first decisions to be made by an owner; is whento engage the services of a Review Board. Based on theauthors experience, the answer to this question is the soonerthe better. Very often, the Review Board will recommend achange in the design concept, and if the project is very faradvanced, it may not be possible to make the change withoutincurring added costs. An anecdote will illustrate the problem.The Board was called in when the project design was welladvanced, andconstructionhadcommenced. The intakedesign had the gate hoist located in a chamber below theconcrete deck, and just above the reservoir full supply level(Figure 1). The Board recommended relocation of the hoist toa position above deck level, to avoid inundation due to awaterhammer surge on turbine full load rejection.Unfortunately, the intake was already being built; gate andhoist were being manufactured, so a change was not possible.At the next development for the utility, the Board made thesame comment, and in this case, there was ample time to makethe change. However, the utility rejected the recommendation,since the intake concept was their standard design. Shortlyafter commissioning the first development, there was a faulton the transmission line, when the reservoir was at full supplylevel, and the turbine was at full load. The surge in the shortintake canal, combined with the 40% waterhammer on loadrejection, resulted in flooding of the intake gate hoist andsome minor damage to the hoist enclosure. This persuaded theutility to accept the Board hoist recommendation on the thirddevelopment, to relocate the hoist to above the deck and todiscard their standard design concept.Hydro Review Boards An important component for a successful development.J. L. Gordon, P. Eng. Fellow CSCE2The utility learned two lessons from this incident (1)listen to the Board, and (2) convene the Board as soon aspossible, when changes can be easily made.Full supply levelReservoirLow supply levelReservoir extremeflood levelAir ventRemovable concrete slabFigure 1. Drawing showing intake gate hoist location.The optimum time for engaging the services of a ReviewBoard is after completion of a pre-feasibility study, and justbefore commencing a full feasibility study. This is when theBoard can review the layout and suggest changes, withoutincurring additional costs for changing a design concept.III. EXPERIENCE OF BOARD MEMBERS.Review Boards should have experience in the type ofproblems likely to arise during design and construction of theproject. Hence a typical Board will have A geotechnical engineer experienced in rock mechanics. Another geotechnical engineer experienced in embankmentdam design and soil mechanics. An engineer familiar with hydraulics and hydro structures. A mechanical engineer experienced in hydro mechanicalequipment such as turbines, gates and cranes.Other members are added if there is a particular problem,such as a structure requiring finite element analysis, or a damwith an element such as a deep cut-off or a concrete face. Aconstruction/cost engineer could also be added if the ownerrequires a review of the project cost. However, this task isusually undertaken by a design-build contractor on smallerprojects, and by the utility on larger projects.The optimum size of a Review Board is about 3 to 5members. A larger Board becomes unwieldy and expensive,and a smaller Board will lack the broad range of experiencerequired to cover all issues likely to arise during execution ofthe work. Note that there is no electrical engineer on theBoard. This is due to the fact that the utility will have therequired experience within their staff to cover all the electrical,control and electronic issues on the project. Nor is there ahydrological engineer, due to the fact that by the time theReview Board is constituted, all hydrology work will havebeen completed, and if necessary, will have been reviewed byan experienced independent hydrological consultant.One of the Board members should be appointed as theBoard chairman by the utility, so that someone can control theprivate meetings of the Board, and ensure that discussionsremain focused on the issues at hand.IV. BOARD LIABILITIES.The question of liability is foremost in the minds of Boardengineers, and is the major stumbling block when trying torecruit members for the Board. The usual insurance clauseproposed for Board member contracts often states Professional liabilityinsurance.A Professional Liability I nsurance policy covering theprofessionalservices rendered . ofnot less than$2,000,000 per claim with a deductible of not less than$250,000 per claim. Such coverage shall be maintainedcontinuously until completionof servicesUnfortunately, liability insurance is just not available tosole practitioners as the insurance industry calls individualengineers practicing in several areas of the consultingengineering industry. Any person providing advice on dams,nuclear plants or environmental work, cannot obtain liabilityinsurance; the risks are just too difficult for the insurancecompany to assess. Hence, the utility or project owner has toinclude liability exclusion in contracts with Board members;otherwise they will be unable to recruit any engineers. Theusual liability limitation on a contract with a Review Boardmember states Limitsonliability.Themaximumamount ontheUndersignedtotal aggregateliability to ABHydro relating to or arising out ofperformance of the Services or of the Contract shall belimited to the total fees paid to the Undersigned under theContract duringitsterm. TheUndersignedshall not beliabletoABHydrofor anylossof revenuessufferedbyABHydro.Where liability exclusion is not possible due to policystandards imposed on the utility, the Review Board may berecruited through the consulting engineer, with Boardmembers paid by the consultant, and their liability insurancealso paid by the consultant as an extra to the consultantsliability insurance. This arrangement is not the best, since itinhibits - to some extent the impartial work of the Board,particularly when a Board comment may reflect negatively onthe work of the consultant.V. TERMS OF REFERENCE FOR BOARD.The project owner should provide some terms of referencefor the Board, and allow the Board to comment on the termsafter the first meeting when the project concept has beenexplained. The terms should include a list of the parameterswhich the Board accepts as a given, not requiring any reviewor comment. These parameters usually include the principalproject characteristics such as reservoir and tailwater levels,installed capacity, flood and diversion flows.Projectcostis usually also excluded from the reviewprocess, mainly due to the fact that the developer will have abetter understanding of local costs.The terms of reference would include a list of the projectfeaturesthe developerand the consultant wish to havereviewed,plus any other items the Board suggests after3becoming acquainted with the project. Typical general termsof reference would be as follows (2) 1. Review the project design concepts, excluding all items andconcepts listed in Appendix X. (List provided)2. Provide comments on the suitability and adequacy of theproposed designs. Offer suggestions and recommendationsto enhance or improve the designs.3. Provide comments on proposed construction methodologiesand/or methods to ensure timely completion of the project.4. Review the quality of the designs and completed works toensure compliance with project specifications and standards.5. Review the adequacy of the project schedule and providecomments or recommendations on possible changes to theproject schedule to ensure completion on schedule.6. Provide brief reports on completion of the Board meetingsto the project Owner.7. Propose necessary meetings of the Board, and to schedulesuch meetings.VI. ORGANIZATION OF MEETINGS.A liaison engineer is usually appointed by the owner, toorganize meetings, secretarial services, hydro site inspectionsand followuponanyrequests for further informationrequested by the Board. Most Review Board meetings lastabout a week, and are organized as follows Board members travel to the meeting office on a Sunday. Monday is spent on formal presentations by the consultantand developer, with a CD of all report and PowerPointpresentations provided to each Board member. A paper copyof the presentations is convenient, but adds to the bulk andweight on travel, and is usually left in the meeting room. Tuesday is spent on travel to the site, presentations by sitestaff on construction and geotechnical investigationprogress, followed by a site inspection. Where the sitecovers a considerable area, it is usual to provide Boardmembers with a site map showing the route taken during theinspection tour and locations of stops. During the evening,the Board often dines with site staff, and one of the Boardmembers may present an informal paper on a similar projector site where there may be similar issues. Wednesday is spent on completing the site inspection andtravelling back to the office. Thursday is devoted to preparation of the Board report.During this time, secretarial services are provided by theowner or consultant, for reproduction of draft reports, andthe liaison engineer is on hand to follow up on any requestsmade by the Board of some project aspect. Typing of thereport is normally undertaken by the Board members ontheir own laptops. Friday morning will see a continuation of the Board reportwork, with completion by noon. The formal presentation ofthe Board report will occur in the afternoon, followed by theBoard members travelling back home in the evening.The Boards report normally has a 1-page covering lettersigned by all Board members prior to departure. In somecases, the report may not satisfy the requirements of theowner, or may not fully explain the reasons for arecommendation. In such cases, the deficiencies are discussedat the final meeting, and arrangements are made to revise thereport, with Board members consulting each other via theinternet.VII. SITE INSPECTIONS AND ARRANGEMENTS.Most Board members are over about 60 years old, and mayhave some mobility issues. This should be taken into accountwhen organizing the site inspection. Steep slopes, very roughterrain and long walks should be avoided. Also, an individualshould be delegated to keep an eye on the Board members, toensure that they do not stray into a dangerous area whereequipment may be working.All utilities are very aware of the dangers associated withconstruction work,and pride themselves on accident-freeprojectconstruction.Atone site,the contractorssafetyengineer enquired about the Board members, and was advisedthat one was well over 70, and another used a walking-stick.The 4-member Board, onarriving at the damsite, wasastonishedtosee a plywoodsidewalkbeinghammeredtogether by a half-dozen carpenters, leading from a road overbare rock down to the center of the dewatered river channel(Figure 2). The sidewalk had stairs and a handrail where theslope down was steep. Later, when Board departed, carpenterswere just behind, dismantling the sidewalk! An extreme case,but it does illustrate the project owners concern for safety.Another concern is the length of the working day. It shouldnot exceed 7.5 hours. The Board members usually spend theirevenings discussing the work and agreeing on who shouldwrite what.Sometimes the discussions can become quiteheated until a consensus is achieved.Plywood sidewalkFigure 2. Dewatered Eastmain River with plywoodsidewalk under construction. June 2004.VIII. BOARD REPORTS.Most reports are organized to facilitate their production in aminimum of time. The usual format includes A covering letter with no mention of the reportrecommendations. It merely serves as a method of directingthe report to the projectowner.Space is provided forsignature by all Board members. An index, prepared by the secretary. An introduction,summarizing the itinerary,design andconstruction progress since the last Board meeting.4 A series of sections written by each Board member on theirparticular interest in the development, including anyrecommendations. A concluding section summarizing the recommendationsand drawing attention to those that are most important. An appendix (#1), prepared by the owners liaison engineergiving a detailed account of the itinerary. An appendix (#2), prepared by the owners liaison engineerproviding a list of all attendees at the meetings, and a list ofall reports and PowerPoint presentations made to the Board. An appendix (#3), to include any calculations, drawings orphotographs prepared by Board members deemed to be anessential part of the report.The last appendix is a rare addition, since Board membersprefer to have all calculations undertaken by the consultant,and instead suggest what and how additional calculationsshould be undertaken.Most reports are kept as short as possible, since there is onlya minimum of time available for their production. However,owners should insiston the Board producing atleastareasonable draftoftheirreportprior to departing.Laterrevisions are difficult to produce, since some Board membersmay have other commitments or could be travelling overseaswhere internet connections are not available.IX. TRANSFER OF KNOWLEDGE.Board members have a great deal of experience, the reasonthey have been selected as consultants. This fact should betaken as an opportunity for the transfer of knowledge, byrequesting one or two of the Board members to present aninformal paper on some interesting subject recentlyinvestigated by the member.This would be particularly appreciated by site staff, who donot, by nature of their assignment, have the opportunity toattend conferences or even evening classes at a localuniversity. The most effective time for such presentationswould be on the Tuesday evening at the site conference room,commencing late in the afternoon.A similar opportunity arises at the consultants or ownersoffices, where an invited lecture on some hydro design aspectcould be presented. One recent presentation was on crackingin the concrete face currently occurring at high concrete-facedrock-fill dams in narrow canyons, and the measures beingtaken to prevent such cracking.Of course, the Board member should have sufficient time toprepare the lecture, particularly if the subject has not beenpresented previously. However, very often the Board membermay have a ready-made lecture from a previous conference,and this could be presented on short notice if the subject is ofinterest to the local engineers.X. REVIEWBOARDS FOR SMALLER DEVELOPMENTS.Most large hydro projects now have Review Boards. Thequestion is then why not for smaller projects. One answer isthat Review Boards are considered to be too expensive, andwith limited engineering budgets, smaller projects are unableto afford the expense of a Review Board. However, the authoris of the firm opinion that scaled-down Review Boards arerequired on smaller projects, based on the following incidents.Propane torch(A) (B)Figure 3. Desperately trying to unfreeze spillway gates.(A) Upstream view, propane torch melting ice.(B) Downstream view, iced in gates, 2 of 14.(A)(B)Figure 4. (A) View down intake air vent. (B) View oftailrace. Both views show air entrainment.EfficiencyHead, feet 10 15 20 25Flow, cfs.Output, kW.Figure 5. Performance chart for 9-blade propeller turbine.The design mistakes currently being made on smaller hydroprojects are just too numerous to ignore, such as The use of unheated gates on a northern flowing river wherespring thaw flows arrive before ice is melted (Figure 3). Intake gate water velocity close tospouting velocity,causing air entrainment and lower turbine output (Figure 4). Unrealistic performance for small turbines (Figure 5). The location of an abrupt right-angled bend in the penstockimmediately upstream of the turbine. The use of a relief valve in a long penstock with a kneewhere negative pressures would occur. An intake design with a trashrack back-flush featurewhich allows unscreened water to enter the conduit. Widely spaced trashracks, allowing hard tree-root sinkersto pass through and crack the Turgo turbine runner blades. Tunnel rock traps with no access for cleaning.5 Spillway drop-down flap gates with hinges at bottom, at thesame level as the bottom of the river, where downstreambackflow can deposit debris, hindering gate operation. An impulse unit set with the jet nozzle level below the 1/10tailrace flood level. Intake with inadequate submergence (Figure 6). Powerhouse with no crane, where a crane was added aftercommissioning (Figure 7), when it was found that mobilecrane rental costs were becoming excessive. No emergency exit in a powerhouse (Figure 8). Improper draft tube design. No downstream vent at by-pass turbine installed at pressurereducing valve in pipeline resulting in excessive cavitation.VortexFlow directionFigure 6. Very large vortex at intake with inadequatesubmergence.Figure 7. Powerhouse containing 2 inclined axis SAXOunits. Exterior crane added after units installed.Figure 8. When construction over, no emergency exit.A couple of detailed case studies will illustrate some of themore complex types of problems being encountered.The first case involved the addition of a powerplant to anexisting storage dam. The feasibility study had recommendedusing a single vertical axis Kaplan unit in a powerplant with arepair bay set just above extreme flood level, which was some10m above the normaltailwater level.Due to the hightailwater, the top of the generator would be below the repairbayfloor, a not unusual occurrence. This arrangementminimized the footprint below turbine floor level, and henceminimized any tendency towards floatation.Water-to-wire tenders were called for the equipmentwithout any limitation on the type of turbine unit required. Thelow bid was for two horizontal axis standard design Francisunits with the shaft set 3m below tailwater, and a runnerdiameter of just less than 1.8m, the maximum for horizontalaxisFrancisunits.The deeperthan normalsetting wasrequired to counter cavitation in the turbine due to the highflow being passed through the runner at design flow and head.A more normal setting for a horizontal axis small Francisturbine would be for the shaft at about 1m above tailwater.This arrangement meant that the flood level would now be13m above shaft level, and about 14.5m above powerhousefloor level.The contractwas awarded for the equipmentwithout undertaking an analysis of powerhouse costs,including equipment erection costs,which would increasesubstantially due to the added rental cost of a mobile crane.The powerhouse became a large rectangular building with theroof level 0.8m above tailwater, with a hatch in the roof forlowering the equipment by a rented mobile crane, down onto avery small repair bay. The volume of concrete inthepowerhouse was about three times the normal volume to avoidfloatation, despite the use of anchors to bedrock.The end result is a powerplant with very difficult access,and an interior layout so crowded, that it is not possible toeasily access the equipment for repair (Figure 9A).(A) (B)Figure 9. (A) Generator rotor removal at a semisubmerged powerhouse with tailwater at roof level, andminimal repair bay. (B) Measuring plumb-bob movementto within 0.0005 inch in flexible powerhouse.6The second case involved the construction ofa newconcrete dam and powerplant containing two large horizontalshaft S-type Kaplan units, with a runner diameter of 3.2mand with the intake structure forming the upstream wall of thepowerhouse (1). The equipment was installed and alignedwhen the reservoir was empty. After filling the reservoir, itwas noticed that the upstream thrust bearing,which wasanchored into the upstream wall of the powerhouse, was out ofalignment. Very precise measurements were taken with theturbine water passages empty (Figure 9B), and later full ofwater, with the water retained by closing the draft tube gates.These measurements indicated that (facing downstream) theright hand unit bearing was tilting down and to the right, andthe left unit bearing was tilting down and to the left, indicatingdeflections within the upstream wall. A comparison with otherpowerplants with similar-sized turbines indicated the lack of acentral thrust pier between the units. The upstream concretewall was correctly designed from a structural standpoint, withdeflections well within those allowed by the building code.However, the deflections were far too high for a concretestructure acting as an anchor for mechanical equipment, wheredeflections within the foundation are just not allowed. Theunit was re-aligned, and wear on the bearing will be higherthan normal as the reservoir fluctuates seasonally.In both these cases the owner was building their first hydrofacility, and in both cases, the consulting engineer lackedsenior hydro engineers within their staff. Both problems wouldhave been spotted by a Review Board, and in the first case, theBoard would have requested a comparison of W/W equipmentcosts, to include the completed powerhouse cost.As mentioned, cost is the prime deterrent for use of ReviewBoards on smaller projects. This can be resolved, to someextent, by using only one or two senior engineers, and relyingon them to recommend additional experts if problems areencountered outside their area of expertise. Further savingscould be attained by eliminating the site inspection.Figure 9. High Falls powerhouse.An example of using a Review Board on a small project wasat the 44MW, 44m head High Falls re-development project forBrookfield Renewable Power, where the 2-man Boardsuggested several changes to the project specification,including the use of Kaplan units instead of Francis turbines,and allowing the design-build contractorthe freedom topropose alternative layouts. The constructed project differedsignificantly from that proposed in the feasibility study, sincethe design-contractor could optimize quantities and costs moreeffectively than the consultant.XI. CONCLUSIONS.Most large hydro developments are now designed and builtwith the assistance of Review Boards.The many design mistakes currently occurring on smallerhydro developments warrant the use of small Review Boardson such projects.A Review Board meeting will normally require about 5days, one for presentations, one or two for the site inspection,1.5 for report preparation, and finally about an hour or two forreport presentation. This time frame could be shortened forsmaller projects by eliminating site inspections and forwardingdrawings and reports for review to Board member offices.Review Board members need to be provided with liabilityinsurance since such insurance cannot be obtained byindependent hydro consulting engineers.Review Boards are usually cost-effective, add a measure ofsecurity to the project, ensuring that the design concept issound, and providing peace of mind to the Owner that is morevaluable than the cost of the Board.The preferred number of ReviewBoard members isbetween 3 and 5. Smaller Boards could be used on smallerhydro developments.Board member age and physical ability should be taken intoaccount when organizing site inspections.The best time for starting Review Board work, is prior tocommencing the detailed feasibility study, when changes tothe projectconceptcan stillbe made withoutincurringadditional costs.Review Board members could be asked to present informalpapers or lectures on their work, in the interests of transferringknowledge to local engineers.XII. REFERENCES.Periodicals:[1] Gordon, J. L. The flexible powerhouse, HRW, May 98.Personal communication:[2] From Dr. R. P. Benson, P. Eng.XIII. BIOGRAPHY.Jim Gordon graduated from Aberdeen University in 1952 with a first classhonors degree in Civil Engineering and commenced work with MontrealEngineering. During this time he was the ChiefDesignEngineer for 6hydroprojects whichreceived awards for excellence in design by theAssociation of Consulting Engineers of Canada.He has worked in 15 countries, and for 9 years hewas the Vice-President Hydro, retiring in 1990.Since then, he has practiced as a privateconsultant, providing advice to consultants andhydro utilities on design, cost, mechanicalequipment selection, and has served on ReviewBoards for Newfoundland and Labrador Hydro,HydroQuebec, BrookfieldRenewable Power,Manitoba Hydro and BC Hydro. He was awardedthe Rickey Medal by the American Society of Civil Engineers, and theDistinguished Service Award by the Canadian Electrical Association. He hasauthored or co-authored 86 papers covering a wide range of subjects, fromvortices at intakes, to turbine cavitation and generator inertia. He has been aninvited speaker at 27 seminars, and is the author of 43 Lessons learnedcolumns published by HRW (Hydro Review Worldwide).