Waterpower '99: Hydro's Future: Technology, Markets, and Policy

Carolina Power & Light Company (CP&L) has recently completed installation of new hydraulic operators for intake gates at the Blewett Hydroelectric Plant. The installation plans for the new equipment included provisions for secondary oil spill containment for all system components. This graphical presentation is intended to illustrate the key features of the system that support the design objective for complete oil spill protection.

This paper presents a discussion of the investigations, design, and construction of a seismic modification to the Butt Valley Dam, part of the Upper North Fork Feather River Project, FERC Project No. 2105-CA, which is owned and operated by the Pacific Gas and Electric Company (PG&E). The seismic modification work was required by the Federal Energy Regulatory Commission (FERC) after results of a seismic stability analysis using seismic parameters obtained from an updated seismicity study show that the dam is unstable under seismic loading condition.

The Corbara reservoir on the Tiber river, although designed mainly for power production, is a cardinal element in the flood protection system of the metropolitan area of Rome. Since its completion in 1963, it introduce a marked nonhomogeneity in the peak flood series at the Ripetta (Rome) flow gage, that, in order to assess the natural floods, had to be removed using the reservoir operation records and a rainfall-runoff model. The same model was used also to evaluate the effectiveness of different operative strategies of the reservoir. It was found that, since the season of heavy floods is November–December, at the end of the dry period, when the reservoir is usually almost void, only marginal benefits can be obtained by changing the present operative criteria by administrative regulations.

This report deals with two pumped storage schemes in Southern Germany which have been rehabilitated after 20 and 40 years of service. Their upper reservoirs have received new asphaltic concrete linings applied in extremely wide horizontal paving lanes using the latest techniques of bridge pavers.

This paper will examine ways that the Shoshone-Bannock Tribe has been integrating science with Native American culture. This paper will explain how and why technology mixed with traditional education can take place in the remote wilderness mountains of Idaho. Finally, we will explain how we are doing this and helping two endangered species at the same time: Salmon/Steelhead and Native American youth. These mountains are our living classroom.

Past studies have indicated the existing below-water juvenile fish outfall release site, in the tailrace below the Corps of Engineers' Bonneville Dam Second Powerhouse, is home to large concentrations of predators (pikeminnow) and deficient from a biological standpoint. To increase survival of juvenile salmonid migrants, new above-water outfall structures were relocated and constructed to provide biologically superior release sites for both the Bonneville Dam first and second powerhouse bypass systems.

This paper presents the study of sediment inflow in the La Coche Reservoir in France.

The effects of hydropower projects on the environment and vice versa has been debated at various fora at which the benefits and costs have been compared to great lengths. It is now widely accepted that each project has to be assessed in the context of its unique settings. Only then can one make a judgement as to whether the overall project benefits will outweigh the costs or not, which then assists policy makers in deciding whether to implement the project or not. This paper attempts to predict the induced morphological changes on the Zambezi River as a result of the construction of the Kariba dam hydroelectric scheme, forty years ago. While various approaches and mathematical models exist for such predictions, the improved Lanes' balance equations were used in this paper aiming to ascertain whether the currently prevailing ecological and environmental changes downstream of Kariba could have been predictable.

The need to develop new energy sources in the South African Development Community (SADC) has become more apparent. The signing (1995) of the Southern African Power Pool (SAPP) by nine of the eleven member countries aimed at ensuring regional power cooperation shows how important the countries take energy. As we approach the 21st century it will be prudent that the region seriously considers operating the inter-connected system conjunctively. This paper therefore, tries to estimate the firm energy potential of the Zambezi River within Zambia and Zimbabwe by conjunctive operation of the existing and potential hydro-electric power sites. Firm energy will be defined as energy which can be generated from historical river flows with a reliability of ninety-five per cent.

An analysis of the variability of flow regimes of the Zambezi river basin is discussed using rainfall and discharge series of not less than fifteen years of record. The 5-yearly moving average for three representative rainfall stations in the basin shows a distinct reduction in the amounts of rainfall received over the catchment during the past fifteen years compared to the long-term mean rainfall. Due to the marked daily and monthly variations of the river flows of the Zambezi river basin, the cyclic nature, if any, of the annual flow data series from three different hydrological stations within the basin is investigated. The results show that for the periods of common data series there is a distinct wet followed by a dry period. In particular for the Victoria Falls station which is more representative of the basin above Kariba and which has the longest data series the study has shown that up until the 1945/46 hydrological year there was a decreasing trend in the recorded runoff and thereafter the trend started to increase up to the 1978/79 hydrological year. However, since the early 80's to-date the runoff once more is showing a decreasing trend. Studies of a similar nature have been carried out on the Zambezi in the past using the differential mass flow index. This paper utilises a different approach using the concept of statistical parameters together with the catchment area figures.

This paper attempts to investigate the behavior of pressure waves through specific throttle types at the end of the lower chamber of a surge tank at the connection with the vertical or inclined surge shaft. It presents the results of some recent investigations in which the extent of transmission and reflection of pressure waves in such construction elements were compared. In order to ascertain the influence of various throttles on the transmission of pressure waves, a simple experiment with a 12 m long straight pipe model was conducted in which 4 throttle types (orifice area/pipe cross-section area ratio is 1:8) were used under various steady basic flows with single pressure waves. The throttle types tested were: a symmetrical circular orifice plate with butt edges, a conical symmetrical circular orifice plate with sharp edges, a perforated plate with circular holes and butt edges and a special longer conical circular throttle element. For comparison and also for practical use, the results of the investigations are depicted in the form of transmissions factors in diagrams. The suitability of application of a quasi-steady throttle headless approach in the common unsteady calculation was verified by a standard characteristic method.

This paper is a case study addressing the engineering considerations associated with two recent reconfigurations of 15 kV bus duct at The Dalles Dam powerhouse on the Columbia River. The first reconfiguration consisted of adding a switched bus duct tie between two pairs of turbine generators. One pair of generators is rated 14 MW each; the other pair is rated 82 MW each. The second reconfiguration involved tapping the first bus duct tie with a circuit breaker and feeder for a new 2 MVA load.

The applications present in literature for the determination of the sediment graph, following a stochastic approach, show approximations probably due to the non-linear link between solid and water transport. In this work it has been proposed a configuration for the transfer plus noise stochastic model (TFN) in which the gradient of the input series is added as an ulterior input to confer a non-linear componenet to the dynamic system. It is thus presented an application related to the Rio Cordon basin (Northeastern Italy).

Men came by the thousands from all over the country, many with families, seeking to escape the hell of the depression. For many, it would be trading one form of hell for another. But from that hell would rise one of the greatest engineering achievements of the modern era, Hoover Dam. Almost twice as big as any dam built before, Hoover Dam stands as a powerful monument to the thousands of men who risked their lives in the hell-like environment of the American Southwest to tame one of North America's mightiest rivers. The Las Vegas of the 1930s was a far cry from the glowing neon, glass, and steel metropolis of the 1990s. The Las Vegas of the 1930s was described as "...the last frontier town in America, ... but really dying in its boots." It was a town dedicated to the unrelenting pursuit of pleasure. The streets were lined with salons that openly defied prohibition, gambling clubs prospered, and on Block 16, pleasures of the flesh were readily available - for a price. As wild as Las Vegas was in the early 1930s, what was about happen to its citizens would forever change the face of their town.

River Mill Dam is a large Ambursen (buttress type) dam constructed in 1911 on the Clackamas River in Oregon. Three dimensional finite element dynamic analyses of the dam showed that it was incapable of withstanding the effects of loads from large earthquakes. Specific problems included out of plane bending of the buttresses, and also excessive shear loads in the corbels which support the upstream face slabs. Two general methods of remediating the dam were evaluated in detail: concrete infill and strengthening the structure. Infilling the dam with concrete may be done as a complete infill using roller-compacted concrete or as a partial infill using formed pumpcrete. The latter of the two methods is the less costly. However, strengthening the structure was found to be both technically feasible and considerably less costly than either type of concrete infill. The selected method of strengthening the structure consists of constructing reinforced concrete diaphragm walls running parallel to the dam axis between the buttresses in alternating bays to eliminate the out of plane bending problem, and using drilled-in post-tensioned anchors to solve the corbel shear problem.

The South Fork Tolt Reservoir located about 35 miles east of Settle, was constructed by the City of Seattle in the early 1960's. The Intake Tower, a freestanding reinforced concrete structure 180 feet tall, constitutes a key element of the Reservoir's facilities. Safety inspections and seismic stability analysis undertaken in the early 1990's indicated a potential for significant damage and possible collapse of the Intake Tower during large earthquakes of moment magnitude (M_w) 6.5 at 10 km and 7 at 15 km. The selected upgrade approach called for anchoring the tower to the foundation bedrock, post-tensioning the structure with high-capacity multi-strand tendon anchors.

The seismic stability of the Croton Dam left embankment was evaluated for potential earthquake ground motions. Design ground motions were selected for a maximum credible earthquake of magnitude 6+ with peak horizontal bedrock acceleration of 0.1g. Field and laboratory test results were used to characterize the static and dynamic properties of the embankment and foundation materials. Static finite element analyses were performed as well as dynamic SHAKE analyses to evaluate the expected performance of the embankment. Results showed liquefaction and strength loss in certain zones of the embankment resulting in large deformation of the slope. Remediation of these areas of the dam was necessary. Various techniques were evaluated including drainage, construction of a berm at toe, vibro-grouted stone columns and compaction grouting. Compaction grouting was selected.

Why convert a slab-and-buttress dam to a gravity type dam? The experiences and regulatory role of staff engineers of the Federal Energy Regulatory Commission (FERC) presented in this paper tell why. In 1989 a FERC engineer conducted a special inspection of the Point "A" dam in south Alabama. The engineer observed extensive and unusual cracking in the upstream portions of concrete buttresses that were exposed after a reservoir drawdown. The FERC engineer recommended a detailed investigation of the concrete cracking. This led to a foundation investigation and a stability study of the spillway. Subsequently the FERC required corrective actions, and the owner's engineering consultant responded with a remedial design plan to convert the Point "A" spillway from a slab-and-buttress structure to a gravity dam. Construction was completed in 1992.

Because it is difficult to mitigate the risks associated with fault displacements in a dam foundation, it is widely preferred in engineering practice to avoid siting dams over active surface faults. Occasionally this cannot be avoided and a number of dams have been designed and built to accommodate surface fault displacements in their foundations. This paper presents a case history of upgrading of a large dam, the Matahina Dam in New Zealand, to accommodate potential surface fault displacements in the dam foundation. A conservative and robust design, based on well established engineering principles and multiple lines of defense, was developed and constructed so that the dam will withstand the maximum earthquake that could affect it without uncontrolled release of the reservoir. This paper describes the dam, the seismic hazard, the design criteria, and the design and construction of the dam modifications.

This paper discusses the foundation remedial grouting program on the left abutment of the Dworshak Dam. Since 1972, the time of the initial reservoir filling, seepage flows under the left abutment have increased steadily. With increasing flows, micaceous material emitted from the downstream flumes of the left abutment indicated that fill material was being eroded from bedrock fractures. Upon concluding several studies of the seepage problem, the U.S. Army Corps of Engineers determined that remedial grouting was necessary to reestablish the foundation grout curtain beneath the affected monoliths.

In the first year of operation, the reservoir had experienced significant seepage and tensile cracking in the embankment and may have jeopardized dam stability. Routine maintenance had been performed since 1953 and annual survey movements conducted since 1968. Measuring weirs located downstream of the project have always shown reductions in measured flows after repairs were made. Survey data indicated that between 1968 and 1990, the rate of movement and settlement of the embankment had decreased. However, the movement was still continuing. It was estimated that up until 1991, Dam A and the western portion of Dam B were moving at a rate twice that of the eastern portion of Dam B. This differential movement manifested the tension cracks and sinkholes in the northwest end of the reservoir.

Finite element analysis of three dams, together with their geometrically enlarged or scaled-down dams, was carried out. The heights of these dams ranged from 74.5 m to 400 m. A nonlinear elastic model was utilized to simulate the soil behavior. It was found that the general displacement distributions in a series of geometrically similar dams of different heights were similar. The settlements of the dams were approximately proportional to the square of their heights and the stresses proportional to their heights. The risk of hydraulic fracture in the lower elevations and the core-bedrock contact increased with the height of dam.

This paper outlines general engineering and construction practices and the associated challenges encountered by the project team during the stabilization of a small dam using roller compacted concrete (RCC). The Niagara Hydroelectric Project on the Roanoke River just outside Roanoke, Virginia is a dam 15 m (50 ft) high and 137 m (450 ft) long constructed in the early 1900's of cyclopean concrete. The stability improvement project consisted of buttressing the downstream side of the dam with 7400 m³ (9700 yd³ of RCC. Particular attention is given to several of the construction details such as dealing with seepage through the existing dam during construction, tying the new section of RCC to the existing dam and finishing the exterior face of the RCC. A description will also be given of the time consuming task of cleaning and preparation of the foundation rock and the downstream surface of the existing dam. Engineering considerations which were taken into account during the design process were the need to draw down the pond six feet during construction to reduce the stress in the dam and how to effectively tie the new section of RCC to the existing structure. Also discussed will be the measures taken to maintain run of river and precautions taken against over-topping.

Following exceptional rainfall in the Saguenay region of Quebec between July 19 and 21, 1996, an extreme flood in the Aux Sables River caused considerable damage to the Jonquiere dam and hydroelectric power plant. Abitibi-Consolidated, the owner and operator of the site called upon SNC-Lavalin to design and reconstruct the entire development on Turnkey basis for a fixed price and within a tight time frame. This paper presents an overview of the project and highlights the special approaches and features employed in its design and construction.

Fontana Dam was constructed by Tennessee Valley Authority (TVA) during the period between 1942 to 1945. In 1972 petrographic examination disclosed small deposits of alkali-silica gel, very fine cracks in a few aggregate particles, and a deficiency in calcium hydroxide in the cement paste. Stress relief overcoring indicated longitudinal compressive stresses of approximately 1000 psi in the outer 10 feet of the downstream face in the summer and 700 psi in the winter. Stresses at greater depths were indicated to be 300 to 500 psi. It was concluded that a mild slow alkali-silica reaction, plus an increase in temperature over a portion of the dam was producing an increase in volume. This increase is effectively resisted longitudinally by the foundation, except near the curve in the dam. This paper will discuss the problems caused by alkali-aggregate reaction (AAR), the analysis and the cutting-edge remedial work to date, as well as a long-term outlook for Fontana Dam that will include a comprehensive instrumentation and testing program.

On December 31, 1997, the 34 yeár old steel penstock feeding the 1800 kW HCJB hydro-electric plant unit no. 1 ruptured, collapsing all of the exposed steel pipe upstream of the rupture. A study was initiated to investigate the cause of the rupture and the integrity of the downstream pipe, which remained undamaged. The study included; thickness measurements and strength tests of the undamaged portion of the pipe; and an overall evaluation of the plant. The study indicated that (1) the stress imposed on the remaining pipe was found to be within reasonable design (2) Approximately 56 meters of above ground steel pipe needs to be removed and replaced; (3)the 48 meters of buried steel pipe requires replacement with high density polyethylene (4)an additional upstream 108 meter extension of HDPE pipe to an existing dam for unit no. 2 is needed to eliminate an old settling basin; (5)cleaning and epoxy painting of the undamaged portions of steel penstock is needed to prevent further wall deterioration; (6)economic studies indicated that the restoration work cost was warranted in spite of the age of the turbine generator fabricated in 1911.

Inservice inspection of welds in hydroelectric facilities is performed to maintain assurance that adequate margin exists against postulated failure scenarios. Inservice inspections can be very costly and time consuming, especially when performed from the inside of tunnel liners or penstocks. Performance of appropriately timed inservice inspections can help reduce the cost of unnecessary inspections. Failures can be prevented by performing inspections that consider the fracture mechanics aspects of the material being evaluated. Deterministic fracture mechanics (DFM) methods are typically used to ascertain allowable flaw sizes. Inspection programs based on the need to detect DFM-based allowable flaws are very conservative since they must consider lower bound conservative input. Probabilistic fracture mechanics (PFM) techniques are an acceptable alternative to DFM methods in order to determine inspection intervals. A case study is presented in this paper that describes the use of both DFM and PFM techniques in establishing an inservice inspection program for a buried penstock. This case study provides an excellent example of the benefits of performing PFM to demonstrate the acceptability of extending inservice inspection intervals while maintaining acceptable levels of safety.

Hidroeléctrica Secacao SA (HSSA) completed construction of a 16 MW hydroelectric project in eastern Guatemala in 1998. A number of challenges were encountered during construction and start-up of the project, requiring aggressive project management to meet the completion date. While this paper presents a case history, many of the issues that needed to be addressed (taken for granted on projects in developed areas) are critical and perhaps typical of small and medium-sized projects in remote areas of developing countries. The design and construction of the project involved a team of engineers, contractors, material suppliers, and vendors. As a member of the project team, Duke Engineering & Services, Inc., provided a review of the design, prepared equipment procurement specifications, and provided construction management and start-up assistance with the project. This paper is primarily related to that involvement.

The penstocks at many hydroelectric stations were built between 1910 and 1950 and now exceed their initial design life. Because penstocks are primary pressure retaining structures essential to a station's operation, their safe and reliable condition is critical to a project's financial performance. But the current decrease in energy values has aggravated the inevitable conflict between penstock safety expenditures and project economics. This paper will illustrate how this balance was achieved at two hydroelectric projects that faced major penstock rehabilitation problems.

Construction restraints prevented lining of the interior steel surfaces of the water conveyance system at the Helms Pumped Storage Project prior to putting the plant into service. Since commercial operation began in 1983, the wall thinning due to corrosion and the timing or need for installing a reliable protective lining have been cause for concern. Random inspections have occurred since 1983 to define the rate and magnitude of this wall thinning, but none of these inspections have yielded conclusive evidence as to the true situation. In 1997, an in-depth program to determine the existing wall thickness and the rate of wall thinning was undertaken, with the overall goal of defining the need and timing for the installation of a protective lining. This 1997 study provided quantitative evidence that delay of any lining activities will not effect the structural integrity of the water conveyance system.

The primary life extension technique for penstocks is assuring that the corrosion protective coating and lining is intact and functioning. There are five primary steps that must be performed for life extension. These include (1) Visual inspection determining the age of the existing system, performing an internal inspection of the condition of the internal lining or performing localized inspections at access locations; (2) Thickness measurements to determine the thickness of the penstock shell to insure that there is sufficient wall thickness for safe operation prior to spending money on coating/relining of the penstock. This requires representative ultrasonic thickness measurements to be taken and a statistical evaluation to be performed; (3) Powerhouse operating pressure, assessment done in conjunction with the penstock shell thickness, includes operational tests performed to measure the maximum operating pressures in the penstock. This is done by performing a series of load rejection tests; (4) Stress level evaluation done using the penstock wall thickness measurements and the penstock pressure data, Based on the outcome, it can be determined if the penstock is safe to coat/reline, or the penstock needs to be replaced; and (5) Coating/lining rehabilitation is the phase. Included in this phase is a Contractor qualification process, such as Steel Structures Painting Council's QP1, QP2 and QP3 quality process, selecting the appropriate coating system to minimize down time, specification development, and performing the actual work.

Scott Dam, a concrete gravity structure 120 feet high on the Eel River of California, was constructed in 1920/21 on a weak rock foundation consisting of hard sandstone blocks in a matrix of softer shaley material. The structure of the rock made it very difficult to draw a coherent geological section and the variability of the rock proved a stumbling block to characterizing the strength of the foundation. This paper discuses the methods that have been introduced by PG&E, resulting from company-sponsored research, in order to characterize this material. Three companion papers subsequently discuss the investigations, measurements and analyses by which the dam's margin of safety was confirmed.

Efforts to characterize the foundation of Scott Dam over a number of years were complicated by the extremely variable nature of the rock. The dam, located in the Coast Range of California, has a foundation composed of Franciscan Formation melange. Hard pieces of sandstone and shale, referred to as blocks, are located in a matrix of weaker crushed rock. While it was possible to sample and test both the block and matrix material, determining the engineering properties of the entire rock mass required a new approach. To obtain a statistically valid estimate of the block proportion of the dam foundation, a large number of well distributed borings were drilled through the dam spillway and apron. Obtaining undisturbed samples of the fractured sandstone and shale required large diameter borings and very careful drilling and handling procedures, essentially preparing the sample for testing while still in the field. Due to sample heterogeneity, multistage triaxial tests were used to assess the strength parameters of the rock.

This paper describes the methodology used to model the behaviour of Scott Dam and its foundation corresponding to a rising reservoir. The laboratory testing for Scott Dam had ascribed to the melange foundation the unusually low modulus of 20,000 psi. The rock mass deformability, evaluated by comparing the response of the model to instrumental measures of Scott Dam's tilting and deformation under the load increment produced by flood conditions, was found to be fifteen times greater, but still unusually soft for a rock foundation. We wished to learn how the softness of the foundation might alter conventional concepts about sliding stability, particularly since the contact surface was very rough such that failure could not occur by any simple rigid-block sliding mechanism. A method of calculating the reserve of safety conforming to stability evaluations in rock masses led to the conclusion that the dam had a sufficient margin of safety under all conceivable loading conditions. Particularly germane to this was the finding that the concrete dam would not debond from its foundation under the heel, as might have been expected had the foundation been harder.

Sliding stability calculations covering a range of loading conditions on the overflow section of Scott Dam show that the dam is currently safe. This conclusion is confirmed by observations in the gallery and on the dam exterior that show no signs of structural deformation. In tins paper the methods and results of these calculations are reviewed. The philosophy related to establishing acceptance criteria based on particular values of the factor of safety for a dam that has operated safely for many years and has experienced loading conditions approaching those of the PMF are discussed.

The Eastside Reservoir Project (ESRP) of the Metropolitan Water District of Southern California (Metropolitan) is located about 90 miles southeast of downtown Los Angeles in Riverside County, California. The new 800,000 acre-foot reservoir will double Metropolitan's surface water storage capabilities to meet seasonal, drought, and emergency needs. Metropolitan began planning the project in 1987. The project is on schedule to begin pump-fill of the reservoir in late 1999.

When completed at the end of 1999, the dams of the Eastside Reservoir Project (ESRP) will represent the largest earth and rock fill reservoir project ever built in the United States. Located in southwest Riverside County in Southern California, a total embankment volume of over 110 million yd³ of earth and rock will be required to construct the West Dam, East Dam and Saddle Dam. While the West Dam spans a 1-1/2 mile alluvial valley, the East Dam traverses a 2 mile expanse of small hills and a large alluvial valley. The Saddle Dam will rise about 130 feet above the lowest point in the crest of the north hills. The resulting reservoir will have a surface area of 4,500 acres and a capacity of 800,000 ac-ft. The Eastside Reservoir Project will nearly double Southern California's surface storage capacity, provide six months of emergency storage in the event of a major earthquake, and provide additional water supplies for drought protection and peak summer needs. This paper briefly describes the foundation and embankment design and construction activities for the three dams.

The Eastside Reservoir is formed by two earth/rockfill dams located 4.5 miles apart within the Domenigoni/Diamond Valley near Hemet, California. The total embankment volume of over 110 million cubic yards will rank this as the largest rockfill dam project in United States history. This paper discussed the methods and equipment used to produce the materials and to construct these dams. This paper will also describe how the surrounding mountains were literally moved to build the dams.

This paper describes the major Hydraulic Structures of the Eastside Reservoir Project. These include the Inlet/Outlet Tower, the P-1 Pressure Tunnel, the P-1 Pumping Plant, the Forebay and its connection to the San Diego Canal, the Eastside Pipeline and Secondary Inlet, and the large diameter yard piping. The paper also describes the two fixed wheel gates and the major valves involved in the project.

Extensive state-of-the-art structural analyses, field investigation work, and instrumentation monitoring have been performed over the past few years to ensure that an aging 70 year old concrete dam continues to safely function in accordance with the Federal Energy Regulatory Commission's (FERC) Engineering Guidelines. For years, engineers and contractors have worked at Santeetlah Dam to address concerns caused by the adverse conditions of normal thermal concrete expansion, seepage due to original load transfer, and alkali-aggregate reactivity (AAR) which have caused movement, cracking, seepage, and concrete deterioration. This paper discusses the long-term systematic safety evaluation program for dam rehabilitation that was developed in 1994 and continues to develop as a result of the on-going evaluation of the monitoring data obtained from an extensive instrumentation program.

Santeetlah Dam, a concrete gravity and arch structure, has a history of concrete expansion and seepage due to under assessment of original load transfer, alkali-aggregate reactivity (AAR), and concrete deterioration. Expansion slots were cut in both the left and right sides of the dam during 1947–1950 to relieve temperature and AAR-induced forces. Surveys performed during the 1960s showed upstream tilting and upward vertical movement of the dam. By the early 1990s, the original slots had effectively closed. In order to evaluate overall dam safety as well as to assist with the development of a three-dimensional finite element model, prior to re-establishing the existing slot on the left side of the dam, the dam was heavily instrumented during 1997–1998. The new instrumentation was automated to facilitate data retrieval. This paper presents a brief history of the dam, old and new instrumentation, instrumentation purpose, and data collection.

Santeetlah Dam consists of a gravity and arch structure approximately 1,000 ft long and 200 ft high. Figure 1 shows a plan view of Santeetlah Dam. The arch/gravity dam has experienced movement in the upstream and vertical directions since construction of the dam in 1927. These movements are primarily attributed to concrete growth caused by alkali-aggregate reactivity (AAR). Increased seepage along the lift joints has accompanied the movements, particularly in the left wing wall section. In order to relieve the concrete stress in the left wing wall section, an existing expansion slot will be recut and deepened at the previous location in early 1999. In preparation for the slot cut, both vertical and inclined high capacity, epoxy coated and filled, post-tensioned rock anchors were installed in the left wing wall section. A total of six 1,500 kip design capacity, vertical anchors were installed in the structural block containing the proposed expansion slot to improve sliding resistance of the horizontal concrete lift joints during slot cutting. Two 58-strand, 2,000 kip design capacity, inclined anchors were installed in the downstream face to improve resistance to foundation sliding. These are believed to be the largest inclined epoxy coated anchors installed to date in North America.

Santeetlah Dam, owned and operated by Tapoco, Inc., is located in Graham County, North Carolina, on the Cheoah River. The dam has experienced seepage, progressive cracking, and displacements primarily due to alkali-aggregate reactivity (AAR). This concrete growth has resulted in progressive movement of the thrust blocks and arch in the upstream direction. This paper presents the development and calibration of the three-dimensional finite element model of Santeetlah Dam and discusses how the model was used to evaluate corrective measures for reducing internal stress and controlling movements caused by the concrete growth.

The Southwestern Power Administration (S WPA) has utilized turbine venting modifications designed and installed by the Tennessee Valley Authority (TVA) to significantly improve the dissolved oxygen content (DO) in the turbine discharges from Bull Shoals, Norfork, and Table Rock Dams. This improvement has allowed the turbine generators to be operated at higher power outputs while meeting target DO levels in the discharges.

The hydropower industry is faced today with a number of challenging problems arising from regulations that emphasize environmental objectives in the operation of its facilities. In spite of using a renewable, non-polluting source of energy, inconsiderate development can adversely impact the aquatic habitat either by inducing fish mortality or by deteriorating the quality of the tailrace water. This paper summarizes recent results from our ongoing research efforts aimed at developing advanced Computational Fluid Dynamics methods that are capable of assessing and improving the environmental comparability of hydropower installations.

Owners of hydropower facilities face increasing demands to reduce or eliminate environmental concerns arising from the impoundment and control of once-natural stream flows. These demands, which are rooted in a complex mélange of technical, political, social, legal, and economic factors, are typically applied through regulatory criteria for mitigating the impact of hydro projects on aquatic habitat. The improvement of low dissolved oxygen (DO) in reservoir releases is a major environmental concern for projects with moderate to heavy amounts of organic sediments. When applicable, turbine aeration often is the most cost-effective technology for providing DO improvements. However, opportunities to solve DO-related water quality problems by turbine methods are often overlooked. In some cases this is due to ambiguous accountability for the low DO problem. In other cases, it is due to limited awareness of abating turbine capabilities, limited support for research and development, or a lack of industry-accepted procedures for the analysis and design of these turbines. This paper presents a brief summary of guiding principles used for justifying, specifying, and verifying the performance of aerating turbines. Examples are given for Tennessee Valley Authority (TVA) hydro projects using turbine aeration. A defensible project justification for turbine aeration requires a reliable determination of the site-specific environmental and hydraulic capabilities of aerating turbines and the ability to express these capabilities in economic terms. Specification requirements must define the desired environmental and hydraulic guarantees to be achieved by an aerating turbine, including the operating conditions for the evaluation. Verification is also needed to determine conformance to proposed environmental and hydraulic guarantees, and measurement uncertainty can have a significant impact

The reduction of dissolved gas supersaturation below hydroelectric dams may contribute significantly to a lowering of gas bubble trauma mortality in anadromous and resident fish populations. To address the complex nature of DGS exposures, Aspen Applied Sciences Inc. has developing a Dynamic Gas Bubble Trauma Mortality model. When coupled with river flow, gas transport, gas mixing, and fish behavior models (Richmond el al. 1998 - this conference), the model will allow the biological effectiveness of various gas abatement measures to be evaluated. GBT is a physiological condition that occurs in fish exposed to high levels of DGS. GBT mortality is caused by the formation of gas bubbles in the cardiovascular system. These bubbles block the flow of blood and respiratory gas exchange by the fish. The DGBTM model follows (mathematically and computationally) the changing total gas pressure, ΔP, and temperature exposure history of populations of Pacific salmon and steelhead trout in the Columbia and Snake rivers. The model translates this exposure history into a dynamic description of the cardiovascular bubble growth, and the time varying rate of mortality for the population. The integration of these components over time through a three-dimensional migration route yields a dynamic description of cumulative mortality incurred by the population.

The U.S. Army Corps of Engineers (USACE) Dissolved Gas Abatement Program (DGAS) is studying options to reduce dissolved gas supersaturation (DGS) associated with spill at hydroelectric dams on the Lower Columbia and Snake rivers. In order to address the complex nature of DGS exposures numerical models of gas transport, gas mixing, and dynamic gas bubble trauma were developed for the Walla Walla and Portland Districts of the USACE. These models couple hydrodynamics, temperature, DGS production, DGS transport, and fish distribution information with a dynamic gas bubble trauma mortality model which will provide an estimation of cumulative mortality in fish populations passing Columbia and Snake River dams.

Dynamic thermal and bioenergetics models were applied to help define issues, identify alternatives, and quantify effects of various reservoir releases improvement options for Bull Shoals and Norfork Dams in northern Arkansas.

The Kerr Hydroelectric Project on the Flathead River in Northwest Montana historically provided load-following and peaking power. Typical daily operation of the project caused large and rapid fluctuations in discharge in the river downstream of the project. These flow fluctuations resulted in equally rapid stage fluctuations in the river. However, due to the frequency of these fluctuations and the morphology of the river, significant attenuation of these fluctuations occurred in the 125-km reach of river downstream of the dam. An unsteady river flow model was combined with fish habitat models to provide a tool to aid in evaluation of how dam operations affect fishery resources. The models were used to evaluate the potential impacts to physical habitat along the river for various operational scenarios. The results of the unsteady flow modeling indicated that attenuation of flow fluctuations in the Lower Flathead River would depend on the duration of the fluctuations. Short duration (load-following) fluctuations would attenuate within a short distance downstream from Kerr Dam while longer duration (peaking) fluctuations would be observable at the downstream end of the study reach. Comparison of operation scenarios showed that the proposed changes in operation of Kerr Dam could reduce the historical project impacts on the fish habitat in major sections of the Lower Flathead River based on the physical habitat analysis.

The Hatfield Hydroelectric Project is located on the Black River in Jackson County, Wisconsin. A five-kilometer long power canal connects the reservoir, Lake Arbutus, with the powerhouse. This power canal bypasses a reach of the Black River, Along this reach, the gradient of the river drops approximately 15 meters. This provides the physical features necessary for whitewater boating conditions. As part of the licensing process, a recreational boating study was conducted at various flow releases. As a result of the study, the Federal Energy Regulatory Commission issued a license for the project which contained an article requiring that recreational boating releases be made five times annually. The competition between various organizations is discussed and the cost of these releases in lost power generation is presented.

Many Federal Energy Regulatory Commission (Commission) licensed hydropower projects today are experiencing significant increases in shoreline development and greater scrutiny from resource agencies, property owners, and the public. As development and multiple uses of the shoreline continue to grow, licensees will face more and more challenges related to the affects of such development on adjoining land uses, recreation, and environmental resources. In many cases, piece-meal solutions are not sufficient to address the cumulative impacts of such development and are, basically, ineffective management tools. Licensees will need to address the impacts of shoreline development on a comprehensive basis by adopting a more collaborative approach to managing their projects. In this regard, licensees will need to assess project conditions and requirements, and work closely with project stakeholders (resource agencies, property owners, local communities) to develop goals and guidelines for shoreline management and resource protection. Through effective implementation of these goals and guidelines licensees can meet shoreline management challenges and ensure that their projects are operated and maintained in manner that meets its license obligations and responsibilities throughout the license term.

Avista Corporation (formerly Washington Water Power Company) owns and operates the Noxon Rapids and Cabinet Gorge Projects on the Clark Fork River in Montana and Idaho. The projects are currently undergoing FERC relicensing, in which erosion and sedimentation issues have been an important focus. Within the collaborative process that Avista Corp. is utilizing for relicensing, the erosion and sedimentation issues that have arisen include: pre- and post-project sediment load; the effects of sediment trapping in the reservoirs; erosion of cultural resources; erosion of public and private lands; downstream operational effects; and the effects of interrelated projects operated by different entities. This paper presents a chronology and discussion of the erosion and sedimentation issues that have been identified in the relicensing process over the last five years. It describes how Avista Corp. is working to address those issues, culminating in a settlement agreement setting forth how the issues will be addressed in the Living License^TM.

In 1935, the Federal Power Act was amended to provide that recreational purposes shall be included among the "beneficial public uses" for which hydroelectric project licenses are to be issued. Since 1963, when recreational use plans were first required as part of license applications, licensed projects have been subjected to increasingly detailed obligations regarding recreational resource development. In 1965, the Federal Power Commission issued a policy statement regarding licensees' obligations to provide recreational opportunities and public access thereto. Other regulatory actions included the adoption of Part 8 of the Commission's regulations, requiring licensees to keep the public informed of the availability of project lands and waters for recreational purposes through newspaper notices and posting of project lands, and the requirement to file a regular report, Form 80, on the status and use of recreational facilities at licensed projects.

The Endangered Species Act (ESA) is one of the most powerful environmental laws—designed to prevent the extinction of plants and animals and their habitats. The Supreme Court concluded that Congress intended "to halt and reverse the trend toward species extinction, whatever the cost" and gave "endangered species priority over the `primary missions' of federal agencies." But does it deserve its label as the "pit bull" of environmental statutes? Federal agencies, such as the Federal Energy Regulatory Commission (Commission), must ensure that their actions—in this case the relicensing of non-federal hydropower projects—are not likely to jeopardize the continued existence of federally listed threatened and endangered species or result in the destruction or adverse modification of designated critical habitat [section 7(a)(2) of the ESA]. To assist agencies in complying with the ESA, section 7 requires federal agencies to consult with the U.S. Fish and Wildlife Service (FWS) or National Marine Fisheries Service (NMFS) (referred to here individually and jointly as the Service) if the agency determines that a project will likely affect listed species [section 7(a)(3) of the ESA]. The ESA also prohibits the taking of any member of a listed Fish and wildlife species (section 9 of the ESA).

This paper presents case studies of Environmental Impact Assessment of two dams namely: Wadi Fatima Dam and Ikrema Dam in the Western Region of the Kingdom of Saudi Arabia. Regional setting of the study area has been described and the goals and objectives have been highlighted. The staged research program has been discussed and the main important results have been presented. Recommendations have been made regarding urgent and long term solutions. Guidelines for carying out Environmental Impact Studies for water resources projects in general and with specific reference to dams, have been proposed.

Fish may be exposed to damaging levels of fluid shear stress and turbulence while passing through hydroelectric power plants. The generally assumed locations for such potential damage are the turbine and draft tube passages, although it is possible that fish are also injured during passage over the spillway or through sluiceways and fish bypass outfalls. Unless mitigated, fluid-induced injuries and mortality could frustrate efforts to develop advanced, "fish-friendly" turbines or to provide safe alternate downstream passages. The effects of shear stress and turbulence on fish are poorly understood, in part because of the difficulties in conceptualizing these phenomena, determining their magnitudes and distribution within hydroelectric systems, and then recreating them in a controlled laboratory environment. We define the fluid phenomena that are relevant to the assessment of effects on fish. The magnitudes of fluid stresses associate with man-altered aquatic environments are often considerably higher than those found in natural environments (e.g., normal river flows). However, levels of shear stresses that occur during flash floods appear to be comparable to those expected within a turbine. Past studies of the effects of shear stress on fish are of limited value, mainly because of their narrow scope and lack of instrumentation to measure velocities on appropriately small scales. A laboratory experiment to study the effects of shear stress and turbulence on fish is described.

Development of a hydraulic turbine that is environmentally safe for fish passage continues to be an evolutionary process. The rate of increase of knowledge of mechanisms causing fish injury and mortality has gained momentum in recent years. Recent endangered fish listings on various stretches of major rivers have placed a priority on continuing this effort. Major research is underway by turbine designers, biologists and plant operators in an effort to understand the mechanisms for fish injury in hydraulic turbines and associated water passage structures. Funding by the Federal Government and certain industrial partners is now being provided to stimulate research on mortality mechanisms and to develop advanced hydro turbines designed to address improved survival.

Past studies have indicated the existing juvenile fish bypass system at the second powerhouse located at the Corps of Engineers' Bonneville Dam on the Columbia River in Washington is deficient from a biological standpoint. In an effort to reduce injury and stress, and to increase survival of juvenile migrants passing through the bypass systems at the project, a new juvenile bypass system is being constructed along the Washington State shoreline. The major features of the second powerhouse juvenile bypass system improvements include modifications to the existing downstream migrant channel within the powerhouse, and construction of a 3.2 km long below-grade transportation flume, monitoring facility, and outfall structures along the Washington shore.

The Cowlitz Falls Hydroelectric Project, located in southwestern Washington State on the Cowlitz River, has two 3.6 x 4.8 m (12 ft wide by 16 ft high) low-level sluice gates that jammed when first placed into service in May 1994. These two upstream-sealing gates operating under 28 m (92 ft) of head were derailed by large, nearly periodic, hydrodynamic loading that occurs as the gates are being withdrawn from the conduit. Most surprisingly, the loading does not disappear even when the gates are fully raised within the gate well with the gate lip about 0.6 m (2 ft) above the conduit ceiling. A number of modifications were made to prevent excessive motion of the gates, including installation of a pressing system to keep the gate firmly against the downstream rails, installation of side guides to prevent sideways motion of the gate, and changes to the gate control logic to support the pressing system.

The Tapoco and Yadkin systems, located in Tennessee and North Carolina, owned and operated by Alcoa have a total of 6 hydroelectric dams, built between 1917 and 1957 with a total of 66 tainter gates similar to the gates at Folsom Dam. The six dams are Santeetlah, Cheoah and Chilhowee on the Tapoco system in Tennnessee and North Carolina and Narrows, Tuckertown and Falls on the Yadkin system in North Carolina. In addition to being very old, gate lubrication practices vary both in the type of grease and frequency of greasing used on each of the projects. To prevent a gate failure similar to the one that occurred at the Bureau of Reclamation Folsom Dam on July 17, 1995, Alcoa retained ECI to inspect, analyze and evaluate the condition and structural capacity of the gates at each of these dams.

On the morning of July 17, 1995, spillway tainter (radial) gate No.3 failed at Folsom Dam, California. It was one of five service gates which had been operated by the Bureau of Reclamation since 1956. There was no warning of structural distress prior to the failure. No one was injured, even though there was a sustained release of 1,132 m³/s into the Lower American River. A multi-disciplinary, multi-agency forensic team was formed to investigate the failure. All of the remaining gates were thoroughly inspected for signs of structural degradation, apart from some corrosion, nothing detrimental was found. The failed gate was removed and then thoroughly examined to determine the mode of failure. This examination determined that a diagonal brace joint, adjacent to the trunnion was the initial point of failure. Theoretical finite element models substantiated this study when a trunnion friction coefficient of 0.25 was considered. This value had been confirmed also from friction tests performed on the actual trunnion from the failed gate. Trunnion friction moment was the key factor, and it had been omitted in the original design calculations.

Turbine efficiency measurements were carried out at Unit 5, McNary Dam on the Columbia River in January, 1998. Measurements were made for three different cam curves and one off-cam setting, both with and without ESBS fish screens in place. The cam curves were derived from a previous set of index tests carried out in 1993, and from two different hydraulic modelling techniques of the unit. In each case, power, head and discharge were measured at a series of wicket gate settings. Relative discharge measurement data were collected using Winter-Kennedy taps; absolute discharges were measured with the ASFM. Turbine performance curves were then computed for each case, and the measured performance was compared to that predicted by the modelling techniques and the 1993 index test. The effect of the ESBS screens on the turbine efficiency was calculated; an efficiency loss of 2 to 3% was found over the operating range when the screens were in place. The ASFM is a new instrument, which offers some unique advantages for measuring discharge in low head plants. The principles of each discharge measurement method are briefly reviewed. Factors affecting the accuracy and precision of the ASFM discharge measurement are discussed, and an assessment of the advantages obtainable by using the absolute discharge measured by the ASFM over the relative value provided by the Winter-Kennedy method under these conditions is made.

Ten U.S. Army Corps of Engineers (Corps) hydroelectric generating units on the lower Columbia River were modified to permit operation as synchronous condensers. The need for the additional reactive support, the selection of synchronous condensers over capacitor banks, and the selection of The Dalles and John Day project locations are described. A conceptual design overview is presented as well as the operating scenario for these condenser capable units.

The concept of operating several existing hydrogenerators at The Dalles and John Day Dams for synchronous condensing was proposed by Bonneville Power Administration in 1997, and was studied, tested; designed and installed by contract by mid-April, 1998. Ten units were modified, and were run as condensers from April to November, 1998.

This paper describes the mechanical design of tailwater depression systems to permit synchronous condensing operation of large Kaplan turbine-generators at The Dalles and John Day hydroelectric projects of the U.S. Army Corps of Engineers. A conventional air receiver based system was provided for the John Day turbines while a novel "Back to Back" system using a spare draft tube for air storage was installed at The Dalles.

Acquiring a pumped storage power generation site utilizing river water recently faces several restrictions due to environmental assessment. On the other hand, there are many sites favorable for constructing a pumped storage power plant utilizing seawater in Japan, which is surrounded by the sea. Seawater pumped storage power plants have several advantages such as lower civil construction cost and lower power distribution cost due to their proximity to nuclear or steam turbine power plants. Seawater pump turbines are used under the condition where the corrosion environment is noticeably severe, rather than conventional river water pump turbines. In addition, the pump turbines have many narrow spaces between parts and their major parts are embedded, so that it would be very difficult to apply proper corrosion prevention measures. The problem cannot be solved only by the conventional corrosion preventive engineering.

Measurements of tainter gate trunnion displacements were made at Jackson Meadows Dam, in the Sierra Nevada. A preliminary structural assessment of the gates showed that the anchor rods holding the trunnion assemblies to the spillway piers were not post-tensioned. The trunnion assembly stiffness needed checking to ensure that binding of the gate bearing could not occur. We made displacement measurements of six trunnions during both unloading (reservoir dropping), and loading (reservoir rising) of the gates. The measurement program had some surprising results. The trunnion anchorages were much stiffer than expected, resulting in less-than-expected movements in the horizontal direction. Vertical movements under load were counter to expectations. The trunnions first went down slightly under load, then reversed and moved up when the reservoir level was near the top of the gate. The movements were replicated on all six trunnions. A mathematical model of the gate was developed to understand the measured movements. This case study shows the need for careful design in the placement of measuring devices when evaluating spillway gates, and the use of realistic structural analysis in explaining the results.

The following paper provides information for understanding the significant parameters that determine the reliability, functionality, and total costs for spillway and headwork gate hoists. The technical information covers the unique situations encountered for spillways and headworks. Specific topics include excessive hoist speed and capacity; advantages of low-efficiency, self-locking equipment; motor selection; controls (remote, local, overload, position, and low tech. vs. high tech.); and wire rope selection and lubrication.

For regulation of flow from the outlet works at dams and reservoirs, some type of regulating gate or valve is required. For low-head applications, less than approximately 80 feet, gates or valves are installed at the upstream end of the conduit for flow regulation. For high head applications, above 80 feet, flow regulation is usually done with slide-type gates discharging into a tunnel or gates or valves located at the downstream end of the conduit. The type of gate or valve used for flow regulation depends on many parameters, including the operating head, flow requirements, and available power for gate or valve operation. Historically, the choice of gates or valves available was limited to slide-type gates, various configurations of needle valves, and fixed-cone valves. Recently, designers and manufacturers have developed new gates and valves, such as hooded-fixed-cone valves and jet-flow gates. These new designs provide more options for optimum flow control, discharge patterns, and flexibility in operation.

The Gavins Point Project on the Missouri River near Yankton, SD, includes an earth dam with two alternative methods for making releases, a hydroelectric power plant and a concrete spillway structure. The Gavins Point Project provides regulated releases into approximately 1305 Km (811 miles) of the Missouri River between Yankton, South Dakota and St. Louis, Missouri. By the early 1970's, it was realized that at least three tainter gates must always be available during the winter to make discharges if partial or complete powerhouse discharge capability is lost There are no flood control tunnels or bypass valves. The spillway at the Gavins Point Project has fourteen, 12.39 meters (40 feet) wide by 9.14 meters (30 feet) high, tainter gates. The spillway was designed for a discharge capacity of 16,537 cms (584,000 cfs). The original design included side seal heaters and an air bubbler system to keep the tainter gates free of ice. Tainter gate freezing problems have been encountered since the original closure of the dam in 1955. The capability to reliably make discharges during extremely cold weather is required to assure an adequate water supply and to minimize downstream ice problems. This paper discusses past, present, and feasible future alternatives to assure reliable operation of the tainter gates at the Gavins Point Project.

During inservice inspection of the spillway gates at the Wishon Dam, structural distress was noted in two of the six radial gates, in the double channels which connect the radial arms to the skin plate structure. Upon learning of the condition of these gates, Pacific Gas & Electric Company embarked upon an analytical program to address the structural capacity of these gates, to design modifications to prevent further structural distortions, and to allow return to service in a safe condition. A number of failure mechanisms were investigated, with one particular scenario providing strong evidence relative to the observed distortions. Once a failure scenario was proposed, structural modifications were designed which not only reinforced the non-distorted gates, but were shown to structurally reinforce the distorted gates so that structural acceptance criteria were satisfied.

A numerical analysis has been developed for calculating viscous flows controlled by a vertical lift gate and hydrodynamic forces acting on it. The numerical solution is obtained from the incompressible Navier-Stokes equations. The numerical technique is based on a finite element method. Turbulence effects are simulated by a k-ε turbulence model. The procedure developed here is applied for a vertical lift gate operating in a CESP installation, and the results are compared with available experimental data at various opening positions. Good agreement is obtained for the velocity and pressure distributions.

A procedure to evaluate the safety of a gate structure under seismic loading is presented using the finite element method of analysis. The Westergaard approach of added mass was coupled with the Magnification Factor, in order to consider the effects of the fluid-structure interaction and the dynamic response of the structure. An equivalent static load is evaluated, which represents the hydrodynamic effects on the gate due to a seismic event. The procedure is completed with a static finite element analysis of the structure and comparison of the results with established stress criteria.

The basic motion of radial gate is a rotation motion around the trunion pin and the basic vibration system consists of gate mass, added mass and spring by operation chain. This one freedom vibration system is affected by the water flow through the small gate opening. In small gate opening, the gate movements made to stop or to accelerate the water flow and the reaction from the change of water flow causes the force which vibrates the gate. This relation between gate motion and water flow is same as the self-excited vibration of long shell roller gate. The theoretical equation of motion is written as a non-linear vibration, which contains the gate motion, itself. So the solution of theoretical equation can be solved under a few approximations, and the unstable condition for flow-induced vibration can be derived from this solution.

Yearly cavitation erosion inspections on a turbine can easily cost 5K$ in manpower and up to 50$ per MWhour of production in lost revenue during machine downtime. Cavitation repairs can last from 2 to 4 weeks with manpower, equipment and material repair costs from 15 to over 100K$ depending on machine size and accumulated erosion. Production losses are much more expensive for these long outages. These expenses can now be minimized with the knowledge of the erosion risk associated with operating conditions. The application of the Hydro-Québec vibratory cavitation detection method allows identifying the potential profitability gains that become important in some machine designs. Four case examples illustrate this point.

The California State Water Project (SWP) consists of 29 storage facilities, 18 pumping plants, four pump-generating plants, five hydroelectric power plants, and approximately 600 miles of canals and pipelines extending over two-thirds the length of California. The project requires 13,700 megawatt-hours of electricity a year to deliver the water. Because of the amount of energy needed to pump water, the SWP is the largest single user of electricity in California. This has magnified the importance of upgrading and maintaining all pump and turbine units to their peak efficiencies. This paper will present a discussion of design, fabrication, construction, testing and results of replacing vertical centrifugal pumps impellers at six pumping plants. The majority of the original equipment, placed in service from 1968 to 1972, was made of carbon steel with very little or no stainless steel components and 1960's technology. Continuing impeller deterioration, along with dropping efficiencies prompted the Department in the late 1980's to develop a pump modernization program. This program upgraded thirty pumps, with modern more efficient components made of state of art materials, to increase unit efficiencies to the highest extent possible.

The influence of surface finish on the cavitation performance of turbine runners was investigated using surfaces subjected to grinding, shot peening and sandblasting. The cavitation behaviour of carbon steel overlaid with 308L stainless steel, carbon steel overlaid with Hydroloy HQ 913 weld metal, and martensitic stainless steel casting (ASTM A 743 Grade CA6NM) was studied in the laboratory using a 69 MPa (10,000 psi) cavitating fluid jet. At a low intensity of cavitation CA6NM and 308L samples polished with 600 grit sandpaper showed lower cavitation damage than that of samples ground with 80 grit sandpaper. Grinding along the direction of water seemed beneficial in reducing cavitation damage on samples tested in the laboratory.

Computational Fluid Dynamics (CFD) is now widely used for designing hydraulic equipment for new and rehabilitated hydropower projects. It is the most promising technology to increase performance and reduce cost of hydraulic machinery. CFD is not limited to the design of new turbines but is well suited to investigate hydraulic and/or structural operating problems on existing machines. Computer simulations provide a means of identifying the cause of the problem and developing alternatives to improve machine performance. Hydraulic equipment owners can benefit from the numerical simulations. This paper describes a CFD environment developed to analyze water turbines. An application follows, in which a significant increase of efficiency was obtained on an existing turbine. The hydraulic behavior was found less than optimal. A modification was made in the field to improve the flow, therefore the performance.

Comparative analysis of resonance diagrams for several hydropower plants shows large differences in the maximum resonance pressures. The authors suggest that the knowledge of resonance frequencies does not help to prevent them, and electronic sensing equipment has to be installed where hydraulic systems are at risk.

The paper deals with derivation of a new scale-up formula for the calculation of prototype efficiency and formulas for prototype performance characteristics from model tests. Comparison of present and new suggested formulas for the calculation of discharge, specific hydraulic energy and power of hydraulic machines is presented. Validity of the new formulas has been proved true on the basis of experimental data from the model and the field acceptance tests of pump-turbines of the 650-MW Dlouhé Stráně Project and the 50-MW Štechovice Project.

A study of a numerical simulation of the flow over Pelton turbine bucket is presented. Numerical analyses described were carried out for two different principles of the simulation. The motion of the first and the last water was solved as a motion of one water drop only. Numerical simulations of points located between mentioned two situations on the bucket were carried out for the free surface flow. Results show some reasons of Pelton runner efficiency drop, which were found using this specially developed software.

The Bureau of Reclamation and Woodward Governor Company have developed and tested algorithms for speed governing and load control of large hydroelectric generators. These algorithms were implemented at Mt. Elbert Pumped-Storage Powerplant. The major benefits include enhancing the control of power system frequency and unit power output while simultaneously reducing governor activity and wear. Traditional governors (mechanical-hydraulic, analog-electronic, and digital-electronic) incorporate are adequate for regulating the speed of a hydroelectric generator but, they do not take into account the differences between off-line, on-line interconnected, and isolated (or islanded) governing. The algorithms developed for Mt. Elbert include features specifically designed for each of these situations and automatically detect the proper mode to use. Bus frequency and phase matching during synchronizing, rapid load ramping for interconnected operation, and isolated or islanded operation detection are some of the features that have been developed and tested.

The use of slotless axial-flux permanent magnet machines (AFPMs) as a new class of direct-drive electric generators for the hydropower application is discussed. The proposed hydrogenerator arrangement has special features such as compactness and modularity that are suitable particularly for the development of small-size and medium-size bulb-generator hydropower units. The leading characteristics of AFPMs designed for the hydropower application are given and it is shown that AFPMs allow substantial saving of machine active materials if compared with the conventional synchronous machines.

The paper aims to find a new solution for the power hydrogenerators (66 MVA) cooling, in the view of the increase of the power in the power system. This solution proposes the use of thermal tubes when accomplishing the cooler. By applying this method there is aimed the increase of the operating current of the hydrogenerators from 2420 A, (66 % of the 3630 A - nominal current) to 85–90 % of the nominal current.

This proposed paper presents the reasons/rationale why hydroelectric plant owners should consider upgrading the electrical protection of their generators and transformers to meet today's IEEE/ANSI standards. It specifically outlines the risks assumed by the owners in several functional protection areas where 20+ year old generator protection is inadequate.

There are numerous applications including many low-head hydro facilities, where induction generators offer distinct advantages over conventional synchronous machines. Induction generators, however, have some disadvantages, which need to be evaluated. This paper provides a comprehensive discussion of the major application issues that should be considered before installing induction generators as a major power source.

Experience in stator winding electrical insulation condition assessment has seen OEMs, repair shops, and motor and generator users employ a wide variety of electrical tests. Such tests include hipot, insulation resistance, insulation power factor, surge comparison, and partial discharge tests. This paper reviews and details the purpose, performance and interpretation of each of these tests. Additionally, it provides progressive information from various IEEE working groups, who are actively involved in trying to improve test standards. Particular focus centers on the significant changes proposed for interpreting insulation resistance and polarization index tests.

The Tennessee Valley Authority (TVA) is currently automating the operation of its hydro system. A proposed automation control system (ACS) will control each plant's operation at the plant and monitor its performance from a centralized control center. As part of the automation project, the ACS will combine with an existing WaterView system that performs monitoring, environmental monitoring, and optimization functions at each plant. Under the integrated automation system, the ACS receives a request for plant output in terms of either power or discharge. The ACS transmits this request to WaterView, which computes the optimal unit generations that meet this plant requirement. WaterView then returns these unit setpoints to the ACS for use in setting unit operating parameters.

The total supervisory control and data acquisition (SCADA) system has been developed for the Okutataragi Pumped Storage Power Station and its substation. The system applies an open distributed client-server computer architecture and the state-of-the-art man-machine devices, such as a large mimic displays and CRTs with mouse operation. It also includes the following operator support functions: a fault tree based operator guidance function, a bearing temperature prediction function, and a vibration monitoring function. The SCADA system has been put into commercial operation where its superior capabilities have allowed the entire power station and its substation to be run by only two operators.

As the hydro market-place becomes de-regulated and re-regulated, there is more pressure on energy prices, and also on operating costs. This pressure is felt acutely in the small hydro industry. Operations & maintenance departments are being pressed to improve reliability factors. This includes minimizing down-time due to component and system failure. There is a broad spectrum of turbine equipment types and configurations currently in use in the small hydro industry. This wide variety presents a unique challenge, requiring broad knowledge, creative technical solutions, and a unique network of providers. This paper will detail a variety of mechanical equipment systems currently in use in small hydro turbines, and offer actual experiences with component failures and unique application problems, and the solutions implemented to improve long-term operating integrity. Some of the turbine components covered will be shaft seals, speed increasers, double-regulated machinery, and a variety of wicket gate linkage systems. Other auxiliary systems dealt with will be cooling water circuits, lubricating oil, and hydraulic power units.

The Tennessee Valley Authority has 32 single- and multi-use hydro facilities maintained and operated by Hydro Operations. Due to extreme changes surrounding the workforce, a better method of utilizing a shrinking workforce and capturing equipment history was needed. In 1994, a work management system (WMS) was promoted. The system chosen allows work identification, planning and scheduling, documentation, completion, and analysis. The system includes material tracking capabilities and labor cost. The real success, however, came through workflow strategy teams that developed a philosophy for use, determined activities to be performed, and created roles and responsibilities. The method of doing business determined how the philosophy was developed. Even though a WMS is primarily used for maintenance, it was determined that operations as well as maintenance would be included in system use. The teams established database logic for equipment records, key equipment, and activity codes. They focused on simplicity and consistency as the goal for the end user. Business plan objectives and organizational goals, such as consistency and standardization, across the entire hydro organizations of 13 autonomous plant groups were incorporated into application of the WMS.

Steady seepage in two-dimensional domains is investigated using a dimensionless formulation for variably-saturated media that depends on three dimensionless parameters, M, n, and α. The parameter M is the product of the anisotropy ratio and the squared ratio of the vertical length scale to the horizontal length scale. The parameter n increases with the uniformity of the pore sizes, and α represents the ratio of the domain height to the height of the capillary fringe. For trapezoidal domains, the seepage face height decreased first with decreasing M and increased later at low values of M. The effect of α was maximal at extreme M values, while the effect of n was minor for all (M, α) values. Guidelines for scaling physical systems are provided.

The Metropolitan Water District of Southern California's (MWD's) Eastside Reservoir Project (ESRP) is formed by two earth-rockfill dams, West Dam [2774 m (9100 ft) long, 85 m (280 ft) high] and East Dam [3200 m (10500 ft) long, 55 m (180 ft) high] about 7 km (4.4 miles) apart, within the Domenigoni and Diamond valleys in Riverside County. An earth-rockfill Saddle dam [700 m (3,200 ft) long, 40 m (130 ft) high] closes a low point in the northwestern rim. The Eastside Reservoir will double the surface water storage available in Southern California and reduce the threat of water shortages during drought periods. One of the many hydraulic structures associated with the reservoir is a selective-withdrawal/pump back inlet/outlet structure (I/O Tower). The reservoir will receive water through the I/O Tower from both the State Water Project and the Colorado River Aqueduct. Water will be delivered to the reservoir by the San Diego Canal (SDC) and a 3.66 m (12 ft) diameter conduit. Water from the SDC will be diverted into a pumping forebay. From the forebay, water will be pumped into the reservoir by pumps housed in a pumping plant. Water will enter and leave the reservoir via the I/O Tower and a 4.88 m (16 ft) diameter concrete-lined tunnel within the north abutment of the West Dam. Water will be delivered from the reservoir to the Colorado River Aqueduct through the I/O Tower and a 3.66 m (12 ft) diameter conduit, bypassing the pumping plant. This pipeline will be about 14.3 km (9 miles) long and will discharge into the Casa Loma. Construction of dams began in 1995 and completion of the Eastside Reservoir Project is scheduled for December 1999 with a total construction cost of $800 million. The reservoir will be put to use immediately, meeting water demands during hot summer months and providing critically needed space to store surplus water available during wet periods.

Prior to the construction of Glen Canyon Dam, the Colorado River would warm seasonally from near freezing to about 85° F (29°C). Since construction of the dam, cold water has been drawn year round from the depths of Lake Powell through fixed, low-level penstock intakes and released downstream. Near the dam, these cold releases are tolerated by the nonnative trout fishery, but are below optimal conditions for native species. As the water moves downstream, it gradually warms but not enough to allow endangered, warm-water, native humpback chub to reproduce in the mainstem of the Colorado River. In its Environmental Impact Statement on the operation of Glen Canyon Dam, the Bureau of Reclamation (Reclamation) agreed to study the feasibility of temperature controls at the dam. During this study, Reclamation determined that releases from the dam could be warmed during critical months by withdrawing water from near the surface of the reservoir. The study incorporated Value Engineering methodology to identify concepts and select alternatives for further evaluation. As a result of this study, Reclamation was able to identify a modification to the existing penstock intake structures as the most cost effective means of warming the releases from the dam.

The U.S. Bureau of Reclamation is currently investigating alternatives to improve habitat for endangered fish below Glen Canyon Dam. In their biological opinion on the operation of Glen Canyon Dam, the U.S. Fish and Wildlife Service recommended that Reclamation investigate ways to control the temperature of water released from the Dam. The primary goal is to establish a new population of humpback chub within the Grand Canyon. The humpback chub is currently a listed species under the Federal Endangered Species Act of 1973 and is one of the native fish species that cannot successfully reproduce because of the cold water temperatures in the Colorado River below Glen Canyon Dam. Cold temperatures are not conducive to the humpback chubs spawning or survival in the mainstem of the Colorado River. Scientists believe that increased Colorado River water temperatures would improve habitat for the native fish. However, because of complex ecological interactions between native and nonnative fish and the aquatic environment, Reclamation is proposing to scientifically test this hypothesis. The plan being investigated calls for the power intakes to be modified to allow warm surface water to be withdrawn from Lake Powell. Warm water withdrawals would likely occur during the months of June, July and August. While not quite as flexible as a traditional multi-level selective withdrawal system, like the one recently completed at Shasta Dam (Vermeyen 1998), the proposed modifications would cost much less ($1.5 million vs. $80 million at Shasta Dam) and allow temperature control studies to be conducted.

Management of the resources of the Colorado River system is complicated by a 75-year history of laws, court decrees, treaties, and other agreements. Since the 1970's, the U.S. Bureau of Reclamation (USBR) has used a suite of site-specific, Fortran-based models to provide support in making operational, planning, and policy decisions. Due to increasing demands and constraints on the system, as well as expanding operational objectives, the old models were no longer capable of supporting the decision-making processes. However, given the long period of usage, the models were quite institutionalized in that we and our customer community (representatives of the seven basin states, water districts, etc.) felt comfortable in using the modeling results as a foundation for negotiation and compromise. Consequently, in 1994 the USBR embarked on a research and development program with the primary goals of developing a flexible, generic modeling system and using it to replace the old models. To meet the technical challenges of making the modeling tool flexible and generic, state-of-the-art programming design and development techniques were utilized. The political challenges of replacing the models in practice were met by actively involving the stakeholders (both within and outside of our agency) at the inception and throughout the development and implementation phases.

For the past several years, the Tennessee Valley Authority (TVA), U. S. Bureau of Reclamation (USBR), and the University of Colorado's Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) have partnered to develop a software package called RiverWare for use in modeling multipurpose reservoir systems. RiverWare now offers three different modeling approaches: interactive simulation, rulebased simulation, and optimization. The flexibility of RiverWare makes it a modeling tool that can be used in many applications to support reservoir operations. While interactive simulation and optimization are used by TVA in daily operation of the reservoir system, rulebased simulation is currently being applied as a tool in flood risk studies, and is being considered for use in long-term reservoir policy evaluations. The capability to model the same system in varying timesteps and model run lengths, along with the selection of three modeling approaches with a consistent user interface, makes it very useful for both planning and daily operation of the TVA reservoir system. This paper will discuss the RiverWare applications used by forecasters in TVA's River System Operations. To begin, interactive simulation as it is used in daily operation of the reservoir system along with a RiverWare tool that allows convenient user interaction will be covered. The application of the optimization feature of RiverWare and how this is used in scheduling the TVA hydro system will then be discussed, followed by a description of rulebased simulation and how it is being applied in flood risk studies. Finally, the RiverWare data management utility used by TVA and the hardware used to run RiverWare at TVA will be discussed.

RiverWare^TM is a river basin modeling tool that provides flexibility to model a range of timesteps with multiple solvers including simulation, rulebased simulation and optimization. RiverWare also provides a selection of methods for modeling physical processes. RiverWare's basic structure and solution approaches are described. RiverWare provides various hydropower modeling capabilities to effectively represent hydropower objectives in a broad range of operating and planning models. Several methods of modeling hydropower in simulation include simple equations for the entire plant, a peak/base method for longer timesteps, a detailed plant characteristics method and a method for modeling each individual generator. The economic value of hydropower is calculated in terms of the thermal replacement value in a thermal-hydro power mix. For optimization, hydropower linearization techniques are described, as well as an economic objective to maximize the thermal replacement value of hydropower, trading off the current value of generation against the future value of generation.

This paper describes WOPRO 4.0 and ALLOCATE 2.0, the new hydropower decision support tools based on optimization for real time multi-reservoir operation and planning, that integrates inflow forecasting, reservoir optimization and scheduling, and optimal unit allocation.

Appropriate information technology tools are necessary to keep us well informed on the hydrological situation and give us insights into the relationship between the different forms of demand and supply of water from our water systems. As water has become scarcer over the years, it has become apparent that we need to use it more efficiently. We therefore need information technology tools that provide information to improve our understanding of river systems, water resources, the nature and components of aggregate demand for water. Integrated information technology systems will highlight the hydrological situation better and emphasize the need for an entrepreneurial approach in the use of water. Integrated information systems will also enable us to understand the alternative applications of our water resources and help us ensure optimum utilization. This paper discusses how integrated water resources management might benefit from the use of appropriate and integrated information technology tools. It also reviews the need to respect water as an economic good for various uses including hydropower generation.

The City of Granite Falls, located in southwestern Minnesota, is currently in the process of preparing a FERC License Application for a Minor Water Project at the Minnesota Palls Dam, located on the Minnesota River. The Draft License Application, prepared in February 1997, stated that the proposed Minnesota Falls Hydro Facility would be used to mitigate the peaking effects caused by the Granite Falls Hydro Facility, located 3 miles upstream, such that the flows downstream of Minnesota Falls would equal the inflows to the Granite Falls Hydro Facility. In addition, development of hydropower at the Minnesota Falls site would require directing some of the flow away from the main spillway and through a conduit to the powerhouse. Two major concerns related to river flows were raised during the Initial Consultation stage of licensing: (1) the capability of the Minnesota Falls development to mitigate peaking of the existing Granite Falls facility, and (2) assurance of minimum flows in the riffle section between the Minnesota Falls Dam and the powerhouse tailrace area. The area between the dam and the powerhouse tailrace consists of a natural riffle flow section that is unique in the Minnesota River. While the Minnesota Department of Natural Resources recognized that a net run-of-river system would be a positive step towards improving the aquatic community, they were concerned about potential impacts to the riffle section. Concerns regarding impacts to the riffle habitat resulted in establishing minimum flow requirements. A hydraulic model was prepared to evaluate the ability of the proposed Minnesota Falls operation to mitigate the peaking effects and meet minimum flow requirements in the riffle section. This paper describes the hydraulic model used for the study, the model capabilities, and the results.

For multi-reservoir water conservation operation analysis, a very sophisticated large-scale multi-period mixed integer network flow imbedded linear programming model, that can coordinate the behavior of multi-reservoir operation, is used. Since water conservation is the primary purpose, we can specify an amount of water as an allotment of power production for a power utility company during a specified period. The allotment of power production is converted to the energy generated as post analysis. By deferring the calculation of hydroelectric energy, the hydroelectric power generation can be easily incorporated into the process of long-term multi-reservoir water supply analysis. As an example, it has been applied to the Han River multi-reservoir system in Korea, and demonstrate that there is a good chance of saving a substantial amount of water and getting an increase in hydroelectric generation as well, provided that it can be used in conjunction with a good inflow forecasting system.

The Federal Energy Regulatory Commission (Commission) receives a number of inquiries every year regarding localized flooding near the hydropower projects it regulates. This type of flooding differs from emergency flood conditions that may occur near hydroelectric projects. This paper discusses the Commission's review of instances of local flooding near hydroelectric projects. A project emergency, as defined in the Commission's regulations, means an impending or actual sudden release of water at the project caused by natural disaster, accident, or failure of project works. Localized flooding may occur upstream or downstream of a hydroelectric project during high or increasing river flows. This type of flooding is not generally considered a life threatening event. Instances of local flooding are typically associated with projects where development has occurred close to the edge of the upstream reservoir.

The Headwater Benefits Energy Gains (HWBEG) assessment process requires a great deal of data from both headwater and hydropower project owners. For example, a twelve-year study involving eight headwater and six downstream hydropower projects requires a total of 87,660 individual data points of flow, generation, and headwater project daily storage change, as well as several pieces of annual project cost information. Assembling these data can be time consuming, especially if data received from the project owners require a great deal of correction, analysis, and interpretation. The purpose of this paper is to note HWBEG study data requirements in the context of their ultimate usage. Five major types of data will be highlighted: Headwater Project, Headwater Operations, Hydropower Project, Headwater Cost, and Hydropower Replacement Cost. For each data type, we discuss require information and potential difficulties in analysis, with the intent of informing hydropower and headwater project owners of what data should be supplied to reduce HWBEG assessment time and effort.

Headwater benefits at a downstream hydropower project are energy gains that are derived from the installation of upstream reservoirs. The Federal Energy Regulatory Commission is required by law to assess charges of such energy gains to downstream owners of non-federal hydropower projects. The high costs of determining headwater benefits prohibit the use of a complicated model in basins where the magnitude of the benefits is expected to be small. This paper presents a new user-friendly computer model, EFDAM (Enhanced Flow Duration Analysis Method), that not only improves the accuracy of the standard flow duration method but also reduces costs for determining headwater benefits. The EFDAM model includes a MS Windows-based interface module to provide tools for automating input data file preparation, linking and executing of a generic program, editing/viewing of input/output files, and application guidance. The EFDAM was applied to various river basins. An example was given to illustrate the main features of EFDAM application for creating input files and assessing headwater benefits at the Tulloch Hydropower Plant on the Stanislaus River Basin, California.

The Headwater Benefits Energy Gains (HWBEG) model was developed in the 1960's for use by the Federal Power Commission (now Federal Energy Regulatory Commission, or Commission) to determine energy gains resulting from the operation of upstream headwater projects. The model was originally written as a mainframe program in PL/I, a computer language no longer used by water resources engineers. In 1993, the model was translated by the author and the Commission into the FORTRAN language for use on a PC-based microcomputer. Since 1993, FORTRAN compilers have continued to improve memory access and other capabilities. In 1998, the model was updated for use with the DIGITAL Visual FORTRAN compiler, without any model computational changes. Previously, memory constrictions required that several runs be made to simulate systems larger than 30 reservoirs; with the new compiler, up to 300 reservoirs can be simulated in one model run. The 1998 update also provides significant efficiency improvements, reducing the time required to complete model runs, and includes improved formatting of output for import to spreadsheets and databases, better documentation of variable names, and time and date assignments on output files.

Headwater benefits are the additional energy generation possible at a downstream hydropower project from the regulation of streamflows by an upstream storage reservoir. Federal Power Act (FPA) requires the owners of downstream hydropower projects to reimburse the owners of headwater project for part of the benefits it receives. This paper summarizes various methods the Commission uses to determine the energy gains and explores methods to simplify the analysis while providing a reasonable estimate of energy gains for small non-complex river basins.

According to the requirement of general layout of Xiaolangdi Multi-purpose Dam Project, the three division tunnels of 14.5m and 1,100m in length will be reconstructed into permanent flood discharging tunnels after end of diversion period. The maximum operation water head of the diversion tunnels could arrive 130m or 140m. And the high sediment content water flow could make the problem much more complex. To solve the problem comprehensively, the energy dissipation technology by the use of multi-orifice is applied. To demonstrate the feasibility, a mid test was successfully completed in the sediment tunnels of 4.4m of China's Bikou project Large amount of the different scale model tests also had been made. Three orifices are determined to apply in the each diversion tunnel of Xiaolangdi project and the design was proved to be reasonable, reliable and feasible.

A mathematical model for simulating the gradual failure of earthen dams, due to overtopping, was developed. The model was based on the water continuity, sediment transportation equations (sandy soil and clayey soil), and a breach shape geometric descriptor. The water continuity equation, elevation-storage relation and discharge-elevation equations, as a whole, were utilized via the Newton-Raphson iteration scheme to compute the pool elevation, reservoir storage and discharge during each computational increment. Commencement of erosion was based on the critical shear stress criterion. For sandy soil mixtures, a sediment transport equation developed by Smart was used. And for clayey soil mixtures, a modified DuBoy's type equation was used. Determination of the dimensions of the breach channel during each time increment an iterative one. An algorithm, also based on the Newton-Raphson iteration scheme, was used to compute for every iteration that is completed, the length of the breach channel and the elevations of the upstream end and the downstream end of the breach channel. The assumed breach shape was trapezoidal. The validity of the model was successfully tested by simulating the failure of the Laurel Run Dam that occurred in July 1977, in Johnstown, Pennsylvania.

As part of the development of the Probable Maximum Flood analysis for the Conklingville Dam, a determination of the stage-discharge relationship was required. The dam has a unique mix of outlet structures ranging from the E.J. West Hydroelectric project, to a side channel spillway, to 3 Dow valves and 2 siphon spillways. Determining the discharge capacity of flow through the siphons was based only on the original design data which was theoretical. Further, the interrelationship of the various discharge structures during high flow events was unknown. As a result of these unknowns, it was decided to develop a physical model to accurately determine the stage discharge relationship for this project.

Flood waves have been conventionally distinguished as the Saint-Venant flow (full dynamic wave) and its lower-level approximations (gravity, noninertia, and kinematic waves) depending on which terms in the momentum equation are considered. Investigations are made to explore the effects of channel cross-sectional geometry on the various shallow water wave approximations. Cross-sectional shapes such as trapezoidal, wide rectangular, rectangular and triangular geometry are considered. The flood waves are treated as a sinusoidal perturbation to the uniform flow. The resistance coefficient is evaluated based on Chezy and Manning's formulas. The propagating mechanism can be characterized by two parameters - dimensionless wave celerity and logarithmic decrement that give the descriptions of translation, attenuation or amplification of the flood waves. Comparisons are made between different wave approximations on the dimensionless wave celerity and logarithmic decrement. Effects of the channel cross sectional geometry on wave propagation are summarized for the ease of environmental engineering design, river hydraulics computation, flood control, mitigation and management.

The U.S. Department of Energy's Hydropower Program developed the Hydropower Evaluation Software to model the undeveloped hydropower resources in the United States based on environmental, legal, and institutional constraints. This Hydropower Resource Assessment effort has identified 5,677 sites that have an undeveloped total capacity of about 30,000 megawatts. The Idaho National Engineering and Environmental Laboratory developed the Hydropower Evaluation Software with input from the Oak Ridge National Laboratory and several other federal and state agencies. The Hydropower Evaluation Software uses the Federal Energy Regulatory Commission's Hydroelectric Power Resource Assessment database to identify sites with undeveloped hydropower capacity and the estimated megawatts of undeveloped capacity at each site. The Hydropower Evaluation Software integrates this information with environmental values from the National Park Service's National Rivers Inventory database. The database resulting from this modeling project contains environmental attributes for river segments throughout the United States. These environmental attributes include fish, scenery, wildlife, cultural, and recreation values.

A potentially catastrophic flood was averted in 1997 as the largest runoff in 100 years swelled the system of six large U.S. Army Corps of Engineers reservoirs located on the Missouri River. Record high system releases were required to evacuate excess storage, but were timed to minimize impacts downstream. More than $5.2 x 10⁹ in flood damages were prevented in 1997 by the Missouri River main stem operation.

In this paper, to the aims of management and dam safety, some general criteria to design a telemetering hydro-pluviometric network, integrated into a Geographic Information System (GIS) are defined. The main characteristics of the network and its interaction with a GIS by using hydraulic and hydrological models are evaluated. The use of the integrated system based on the application of GIS and monitoring technique is analyzed in details. Parameters, methodical ones of measure and instrumentation equipment to adopt within the basin subtended from the dam are defined. The modalities of data acquisition and their integration with geographical data in a GIS are described. Flooding area and damages assessment procedures for agricultural land, built-up area can be generated and implemented in the GIS. Finally, an example of design for a telemetering network with a GIS is proposed for some dams located in the Basilicata region, in south of Italy.

The theme of WATERPOWER'99, "It's a Whole New Ball Game", clearly sets forth the message that several new challenges face the hydropower industry. Across several fronts, it will not be "business as usual". This paper will be directed towards certain aspects of the Federal Power Act related to the protection of life, health, and property that were perhaps a foregone conclusion in the hydropower industry. Will these aspects have the overriding emphasis under a restructured, deregulated power industry? This paper will address the issues and potential impacts concerning the possible effect of market prices controlling water releases from hydropower facilities at potential sacrifices of public safety during periods of flood operations. Proper consideration in avoiding operational activities to the detriment of public safety in order to take advantage of market prices must not be a value sacrificed for economic reasons.

Federal Energy Regulatory Commission order 888 required the unbundling of transmission services (such as ancillary services) offered by regulated utilities. Utilities have been struggling to determine a method by which a fair and reasonably equitable rate can be assessed to third parties requesting the use of the utilities' transmission services. This paper describes a generic methodology for determining the cost of production of several hydro generation related ancillary services (products). It can be used for any powerplant where costs of maintaining the powerplant are known and ancillary services are produced. This method is not intended to determine a market rate to be charged for these products. The costs include only those necessary to deliver the products to the generator high-side bus bar or tie line. The services for which cost of product ion are calculated are: regulation, spinning reserve, non-spinning reserve, replacement reserve, voltage support, and black start. The methodology is first applied to a system with only one unit. The values of unit utilization are calculated and total power cost applied to the results. The methodology is then applied to a more complicated system involving multiple units with varying operating parameters and multiple plants.

As hydro companies continue to seek out new business opportunities, they are increasingly looking outside the US. Subsequently, these hydro professionals are faced with an array of insurance and risk management issues unlike those they may be familiar with in the US. This article will address several of the most frequently asked questions which concern the gamut of hydro companies - including project developers, contractors and consultants - who become involved with work outside the US. Without question, the need for more electric capacity in developing countries has created business opportunities for a wide range of hydro companies. As stated in the 1996 Annual Report of The International Energy Agency, "hydropower is the foundation of rural economic development. The areas supplied with electricity from hydropower are ... hard to reach with large national grids and ... have suffered from the lack of or shortage of electricity," Furthermore, it is well known that at one time, most of the work conducted (by US-based companies) outside the US was done so by the largest contractors and developers. It is evident now that even the smallest hydro companies can successfully compete based on their particular expertise.

The Bonneville Power Administration (BPA), primarily through the Federal Columbia River Hydropower System, provides electrical capacity and energy to its customers. Historically, under a regulated electricity market structure, other generation-provided services such as system voltage support were transparently "bundled" together with the basic capacity and energy. As the United States moves towards a more deregulated market structure, these other services can and will be provided separately from basic capacity and energy. This paper presents the results of a valuation study for a specific generation-provided service requested of the BPA: a sudden, large generation drop for transmission system support.

Since 1992, the Corps has required an economic evaluation of major rehabilitation spending comparable to that of new projects. A significant aspect of this evaluation is that it must explicitly account for the current and future reliability of the generating equipment without and with rehabilitation. A risk-based life-cycle analysis framework was adopted that recognizes that the reliability of equipment declines with age and usage but can increase by repairs and rehabilitations. These factors required some rethinking of how to measure capacity losses and capacity values especially within a Monte Carlo model typically used in the analysis. This paper describes the adoption and use of the HMA/TMA method for valuing hydropower capacity for major rehabilitation.

The latest improvements of the HYDRA model are described. It seems still to be the only computer model in the world that computes the economically optimal design of hydropower plants, and thus solves the classical design problem in construction of new projects and rehabilitation of old ones. Up to now it has only been possible to obtain local optima. The best known example of local optimisation is perhaps how tunnel diameters are calculated by minimising the sum of construction costs and power losses in the tunnel itself, disregarding the influence of varying total head on the size of electrical and mechanical equipment and size of powerhouse. The new computer model HYDRA uses an evolutionary method called Genetic Algorithm to find the global optimal arrangement of design and layout of projects by maximising the net profit of power sales. In recent years evolutionary methods, like the Genetic Algorithm, have proved their worth in optimisation problems where the methods of mathematical analysis are not applicable due to system complexity and they offer a new approach in optimising hydropower schemes globally.

Over the next eight years, the Public Utility District No. 1 of Chelan County, Washington (Chelan PUD) expects to produce over 15,000 documents, or more than two million pages of materials, to obtain new operating licenses for two existing hydroelectric projects. If the paper was put in one pile, it would be over 80 stories high. Chelan PUD will be using the web and electronic files to reduce the amount of paperwork by over fifty percent. Recognizing the potential value of this information tool, the Federal Energy Regulatory Commission (FERC) has agreed to evaluate Chelan PUD's web site and use of electronic formats as a pilot project. If successful, all future relicensing paperwork could be filed electronically. Even more importantly, the FERC is considering the possibility of converting all documents filed at the FERC into electronic formats and posting these on its own web site. Another possibility is that the FERC's web site will be linked to other web sites that are maintained by project owners.

The North Umpqua Hydroelectric Project is one of the most complex hydroelectric developments in the country. Eight separate developments are located on three rivers that converge just above a designated Wild and Scenic River. Since the hydroelectric developments are all located within US Forest Service lands of the Umpqua National Forest, the terms of the new license will also have to comply with the Aquatic Conservation Strategy of the President's Forest Plan. At the time of filing the license application, January 1995, the most significant environmental issues were unresolved — anadromous fish passage, instream flows, resident fish passage, reservoir and forebay management, and water quality issues, such as eutrophication and instream flows related to temperature. Based on the complexity of the issues at hand and the volume of study information already available, PacifiCorp committed to conduct a cooperative watershed analysis to interpret the existing data on a watershed scale and reach resolution of the outstanding issues that are driven by the best available science. The analysis is intended to: (1) assist relicensing of the hydro project; (2) improve understanding of the watershed and the effects of the hydro project as well as other land uses on the ecosystem; (3) assist development of strategies for maintaining and restoring the long-term ecological health of the watershed; and (4) guide the allocation of PacifiCorp's resource enhancement budget.

The Council on Environmental Quality regulations require a cumulative impact analysis only when there is an incremental environmental effect resulting from a proposed action requiring federal approval. Where there is no incremental environmental effect resulting from the proposed action, a cumulative impact analysis is not only inappropriate, it is not lawful. The Federal Energy Regulatory Commission wrongfully undertook a cumulative impact analysis in its recent Cushman relicensing proceeding.

California has entered a new era of competitive electric generation. California's Power Exchange and Independent System Operator began to bid and schedule the state's generation in April 1998. The generation industry's dramatic changes, predicted in the mid-90's, have occurred and the path for utility-owned hydroelectric resources is clear — just compete. Right? Wrong!

This paper summarizes the findings from research by Friends of the Earth (FoE) regarding past dam removals across the United States. It includes information on the number, location, size, reason, and date of dams previously removed, as well as brief case studies of five specific removal experiences.

The U.S. Army Corps of Engineers is currently evaluating the effects of removing the four lower Snake River Dams. These dams have powerplants that produce a total of about 11 million megawatt-hours of energy annually and have a combined maximum capacity of about 3,500 megawatts. This capacity represents 15 percent of the total Federal hydropower system capacity in the Pacific Northwest, which is about 23,300 megawatts. The dams are being considered for removal in order to improve migration for salmon that are listed as endangered under the Endangered Species Act. Dam removal is being investigated as an option along with other actions such as installing surface bypass systems to get the fish safely around the dams. The effects of dam removal are being evaluated in various areas including hydropower, fish passage, navigation, irrigation, recreation, water quality, and others. The focus of this paper is on the impacts to power generation, however effects in other areas such as fish survival will also be summarized.

The energy crisis and federal incentives initiated in the late 1970s led to development of many small hydroelectric projects by municipalities. The City of New Martinsville, West Virginia constructed a 35-megawatt project at the Hannibal Dam in 1988, providing a major addition to renewable electric power in the Midwest. The City plans two additional projects, possibly in cooperation with other municipalities in the region. New hydropower at existing navigation dams, such as Hannibal Dam, can provide renewable, low impact power in a manner consistent with the developing standards for such "green" power in the competitive electric marketplace. These plants can also contribute to the new capacity increment needed in the region, and can help municipal electric utilities maintain their independent status. Members of the hydro development community need to encourage the valuation of hydro project impacts in a fair manner by any entity endorsing renewable energy sources.

In industrialized countries there is a strong resistance in general against utilizing the huge global resources of hydropower for electricity production. The fact is that hydropower is the only big renewable non-polluting energy source for electricity production which is available during the next twenty years. An other available energy source for large scale electricity production without CO₂ -production could have been nuclear power, but this energy source is not accepted due to the risk of radiation from stored waste with available technology in the nearest future. The environmentalists are at present time misleading the public by painting a picture showing that wind power, solar energy, bio mass energy etc. are alternatives for the global need of electricity production in order to increase the standard of living in developing countries. The paper describes why bio-mass energy, solar energy and wind power cannot be an alternative, but only a supplementary source for electricity production with available technology. The paper will give a brief history of the development of hydropower and the possibility to increase the present global electricity production by up to 40 % if the technical- economical resources of hydropower are developed.

Various papers have been written on hydropolitics and this subject is becoming popular worldwide. The Hydrological cycle is largely controlled by natural forces. The natural occurrence and availability of both surface and underground water is also controlled by natural forces. Both underground and surface water flow-regimes know no political boundaries. However, because humans have mapped out political boundaries delineating each sovereign state, watercourse systems become international. In the Southern African Development Community (SADC) region, the issue of internationally shared watercourse systems is becoming more relevant as human population grows and the demand for water for industrial and commercial purposes increase. However, is water a political issue yet in the SADC region? This paper discusses the hydropolitical situation in the SADC region relative to other regional developmental issues

From the ice age to slackwater, the Columbia River continues to ebb and flow through our lives. This paper will explore the ebb and flow between natural and human ecosystems. The new science of chaos will be introduced as a means for further understanding these ecosystems and how it shapes our management of water policy in the Pacific Northwest. Just as natural ecosystems flow between order and chaos, our institutional management systems follow a similar governance structure. As examples of this ebb and flow, I will compare and link traditional and contemporary water management, historic policy issues with current issues, and natural systems management with human management. Through this comparison and linkage, I will provide another perspective on our sometimes chaotic management to slackwater.