Browsing by Author "Dahlin, Warren Q."

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Con Edison Intakes, Arthur Kill No. 2, Hydraulic Model Studies
(1987-11) Dahlin, Warren Q.; Wetzel, Joseph M.
Culver-Goodman Tunnel Control Structure Model Studies
(St. Anthony Falls Laboratory, 1980-06) Wetzel, Joseph M.; Dahlin, Warren Q.
The City of Rochester plans to excavate the Culver-Goodman tunnel and connect it to the existing Cross-Irondequoit tunnel through a control structure which will limit the flow diverted for treatment to about 1050 cfs. A 16 ft diameter entrance tunnel with a round to square transition at the downstream end conveys the incoming flow to a distribution chamber. The original design, Type A, distribution chamber is 100 ft long by 76 ft wide, contains 1:1 side slopes, blocks at the upstream end to dissipate some of the energy of the incoming flow, and an ogee crested weir at the downstream end. The floor of the distribution chamber is at elevation 285 ft and the weir crest at elevation 315 ft. Six sluices each 5 ft x 2.5 ft direct the diverted flow downward into the drop chamber. To enter the sluices the incoming flow has to make a 90 degree turn. The 100 ft long by 20 ft wide drop chamber also turns the flow 90 degrees towards the 12 ft diameter exit tunnel. The drop chamber is required to be of sufficient size to dissipate the energy of the falling water and to reduce the flow velocity so that the entrained air in the water-air mixture can rise to the surface and escape. Blocks at the downstream end assist in this process. The floor of the drop chamber is at elevation 216 ft and the top is open to the ground surface. A transition at the entrance to the exit tunnel guides the flow smoothly into the tunnel.
Culver-Goodman Tunnel Dropshaft Exit Conduit Model Studies
(St. Anthony Falls Laboratory, 1979-09) Wetzel, Joseph M.; Dahlin, Warren Q.
The City of Rochester plans to excavate the Culver-Goodman tunnel and connect it to the existing Cross-Irondequoit tunnel through a control structure. Several dropshafts will convey the effluent from surface collection facilities to the storage and conveyance tunnel. The function of these dropshafts is to transport the water from one elevation and energy level to a lower elevation and energy level and, in the process, to dissipate energy and remove the entrained air. The term "dropshaft" is sometimes used collectively to include the various components of the structure. Conduits at or near the ground surface collect the water and convey it to an elbow which deflects the flow about 90 degrees into the vertical drop shaft. The vertical shaft is divided by a slotted wall which separates the falling water-air mixture and the released air returning to the surface. In the elbow and vertical shaft the falling water entrains considerable amounts of air and gains kinetic energy. The vertical shaft terminates in a sump, which is a large excavated and lined chamber. The purpose of the sump is to dissipate some of the energy, to remove and co~lect the entrained air, and to direct the water at a reduced velocity into the exit conduit. The sloping roof of the sump guides the collected air back to the vent side of the vertical shaft. A portion of the rising air is drawn through the slots in the divider wall and re-· entrained in the falling water; the excess air returns to the surface. The exit conduit conveys the water into the tunnel. A typical model including all of these components
Experimental Flow Studies With the Dual-Screen Cooling Water Intake Assembly ("Riser") for the James H. Campbell Electric Power Generating Plant, Unit No. 3
(St. Anthony Falls Laboratory, 1978-12) Stefan, Heinz G.; Dahlin, Warren Q.; Ripken, John F.; Wood, Addison; Winterstein, Tom
Flow characteristics inside and outside of a dual-screen cooling water intake assembly ("riser") for the James H. Campbell Unit No.3 were observed and measured in hydraulic models at scales of 1:3 and 1:12. Risers consist of dual cylindrical screens with horizontal axis and solid endplates mounted on a T-assembly which is supported by a 3.5 ft diameter vertical withdrawal pipe. Pressure losses within the assembly, approach flow velocity patterns and approach flow velocities on the screen surface were investigated. A total headloss coefficient of 4.6 resulting in an equivalent full-scale headloss of 8.0" of water at a withdrawal rate of 29.44 ofs through the assembly was measured in the model. Flow patterns towards single and multiple risers were observed by dye tracing techniques. Approach flow velocities were measured on the surface of the 1: 3 scale riser model. The highest velocities were found near the center of the screen and the lowest ones near the projecting endplates. Maximum local velocities exceeded calculated average velocity by about 30 per cent.
Hydraulic Studies of the Spillway for the Mangla Dam
(St. Anthony Falls Laboratory, 1968-02) Anderson, Alvin G.; Dahlin, Warren Q.
The Mangla spillway is an excellent example of the interdependency of hydraulic design, structural design, and economics, each of which has a bearing upon the project. This final report of the experimental program describes a long series of experiments to test different design concepts that were evolved to meet the demands of the field conditions. The initial studies dealt with the ski-jump principle, which for reasons of cost was attractive. However, because of the excessive scour of the relatively non-resistant foundation material in the neighborhood of the main embankment, this was abandoned and the research was dissipated in a stilling basin. The very high uplift forces associated with this particular application of the single stilling basin scheme led eventually to the two basin scheme, in which the pool floor of the upper stilling basin is located approximately at tailwater level to eliminate high uplift forces.
Intake Hydraulic Model Study for the St. Cloud Hydroelectric Project
(St. Anthony Falls Hydraulic Laboratory, 1987-04) Gulliver, John S.; Dahlin, Warren Q.; Woods, Judson
This report describes a hydraulic model study of the intakes and related approach flow regions for the St. Cloud Hydroelectric Project. The study was conducted for Warzyn Engineering and the M. A. Mortenson Company. The hydroelectric facility will be composed of two 4-Mw pit turbine/generator units utilizing approximately 17 ft of head with a design flow of 3,250 cfs each.
Model Studies - Lawrence Avenue Sewer System, City of Chicago
(St. Anthony Falls Hydraulic Laboratory, 1968-10) Anderson, Alvin G.; Dahlin, Warren Q.
The Lawrence Avenue Sewer System will incorporate a large deep tunnel for temporary storage of the surface runoff that will be fed to it by a series of drop shafts placed at intervals along the axis of the tunnel. Each drop shaft will be designed to handle a variable discharge, the peak value of which will be different for each. As the volume of runoff increases, the tailwater elevation may change from zero to a maximum which is governed by overflow facilities. The objectives of the research described in this report are (a) to investigate the nature of the flow in the drop shafts, suggest an optimum design, and describe the flow patterns in the final design; and (b) to examine the surges in the overall system when it is subjected to discharges of various magnitudes and in various sequences.
Model Studies of A Cooling Water Discharge Outlet Modification Prairie Island Nuclear Generating Plant
(St. Anthony Falls Laboratory, 1981-03) Wetzel, Joseph M.; Dahlin, Warren Q.
The P~airie Island Nuclear Generating Plant is located on the Mississippi River near Red Wing, Minnesota. 'The general location is shown' in Fig. 1. The plant is situated on. the right bank in the bend of the river about one mile above Lock and Dam No. 3 as shown in the frontispiece. The cooling water is presently discharged through an open canal directly into the Mississippi River. The present outlet is i.n rathe~ close proximity to the plant inlet resulting in some recirculation of the ~armer water. Northern States Power (NSP) also has need for preventing fish from entering the outlet canal where they would be subject to cold shock mortality in case of sudden winter shutdown.. Modification of the di.scharge outlet nas therefore been proposed. The discharge outlet would·be moved further downstream and the cooling water discharged into the river 500 ft downstream of Barney's Point, thus reducing recirculation. This may be seen in the frontispiece and the sketch. in Fig. 2. . Dikes buil·t across a backwater area adjacent to the plant would provide an impoundment area for the plant discharge.. Four pipes with diameters of 8, 7,· 6 ,·.and 5 ft would convey the flow through the embankment and discharge it into the river. The velocity of the flow from the open pipes would be maintained above 8 fps. This high velocity would prevent most of the fish.from swimming through the pipes and entering the impoundment pool. During .operatiop., the pipes would be either closed or wide open, and the number of open pipes would vary from 1 to 4 depending on the plant dipcharge. By proper selection of the pipes to be opened, the·head can be maintained at a fairly constant elevation, thus keeping the discharge ~elocity greater than the required 8 fps.
Model Studies of A Cooling Water Discharge Structure Modification - Monticello Nuclear Generating Plant
(St. Anthony Falls Laboratory, 1980-04) Wetzel, Joseph M.; Dahlin, Warren Q.; Dhamotharan, S.
The Monticello Nuclear Generating Plant is located on the Mississippi River near Monticello, Minnesota. The genera'l location is shown in Fig. 1- Cooling water is presently discharged through a wide canal directly into the Mississippi River. Northern states Power Company (NSP) has need for preventing fish from entering the canal where they would be subject to cold shock mortality in case of sudden winter shutdown. Modification of the canal outlet to the river has therefore been proposed. The outlet of the canal would be closed with a wall that incorporates an overflow weir. The elevation of the river crest was selected by NSP to minimize the possibility of fish jumping over the weir and entering the canal during winter.
Model Studies Of The Cooling Water Outlet Channel From The Allen S. King Generating Plant To Lake St. Croix
(St. Anthony Falls Hydraulic Laboratory, 1966-07) Silberman, Edward; Dahlin, Warren Q.
The Northern States Power Company is building the Allen S. King Generating Plant, a thermal plant, on Lake St. Croix between Stillwater and Bayport, Minnesota. Operation of the plant requires that water be drawn from Lake St. Croix, used for condenser cooling purposes. and then discharged essentially unchanged except with a higher temperature, back into Lake St. Croix at a location downstream from the intake. The first unit of the plant, requiring 660 cfs of condenser cooling water, is now under construction. It is planned to add a second unit later making a total requirement for condenser cooling of 1500 cfs. Pioneer Service and Engineering Company is designing the plant.
Model Studies Of The San Lorenzo Spillway Executive Hydroelectric Commission Lempa River El Salvador, Central America
(Saint Anthony Falls Laboratory, 1978-06) Wetzel, Joseph M.; Dahlin, Warren Q.
The San Lorenzo Project is located on the Lempa River in El Salvador. It is the smallest of the Central America republics with an area of 8,260 square miles and a population of about 4 million. It is a mountainous country with many volcanoes and upland plains, bounded by Guatumala, Honduras, and a 160 mile coastline of the Pacific Ocean as shown on Chart 1. The republic is primarily agriculture but is developing its industry. The capital is San Salvador.
Parshall Flume Calibrations Approach Studies 12-inch Throat
(St. Anthony Falls Hydraulic Laboratory, 1988-12) Dahlin, Warren Q.; Wetzel, Joseph M.
The Metro Waste Control Commission (MWCC) of St. Paul has installed Parshall flumes in sewer manholes at various locations to. monitor the discharges. The Parshall flume is an accurate measuring device for open channel flow when installed as specified in the standard manuals. This calls for ideal approach conditions, which may not always be possible in manhole installations. The MWCC proposed to investigate the accuracy of Parshall flumes in these installations. A literature search revealed very little definitive information on the effect of adverse approach flow conditions on the accuracy of discharge· measurements. A study of Parshall flume calibrations for various approach geometries was initiated. A commercially available reinforced plastic flume with a 12-inch throat was used. This report summarizes the studies.
Phoenix-Casa Grande Highway Stormwater Interceptor Drop Structures Model Studies
(St. Anthony Falls Laboratory, 1985-02) Dahlin, Warren Q.; Wetzel, Joseph M.
The Arizona Department of Transportation is developing the Phoenix-Cas a Grande Highway Stormwater Interceptor Project to handle storm water in the Phoenix area. Rectangular conduits near the ground surface collect the storm water and convey it to a vertical part of the structure which has several components. At the lower elevation is a large excavated chamber called the sump. Extending from the sump to the ground surface is a circular surge shaft containing two vertical walls. A diaphragm wall near the center of the surge shaft forms a dropshaft at the upstream end. The free trajectory inlet and diaphragm wall deflect the incoming water 90 degrees into the vertical dropshaft entraining considerable air. The water-air mixture falls down the dropshaft impinging on the sump invert. The entrained air has the effect of reducing impact pressures on the invert of the sump. A second wall at the downstream end of the surge shaft provides an air vent for returning air to the ground surface. The purpose of the surge shaft is to reduce pressure surges in the system. Downstream of the sump-surge shaft is the deaeration chamber. The sump and deaeration chamber provide for energy dissipation and air removal. Some air rises to the water surface in the surge shaft and escapes; the remaining air is carried into the deaeration chamber where it is removed. The deaeration chamber contains a false crown provided with air slots. The air rises to the false crown and escapes through the air slots to a horizontal chamber above; this chamber conveys the air to the vertical air shaft at the downstream end of the surge shaft. It is desirable to remove most of the entrained air from the water before it enters the tunnels. The entrapped air in the tunnels reduces the capacity for storage and conveyance and introduces the danger of high waterhammer effects upon its sudden release, which could cause damage to the system. The release of high velocity air at ground surface structures could also be hazardous. The effectiveness of the sump and deaeration chamber in dissipating energy and removing the entrained air was one factor considered in the evaluation of the various types tested. At the downstream end of the deaeration chamber a cylindrical surface was provided as an efficient entrance to the transition. In the transition the cross section gradually changed from a square section to the round section of the exit tunnel. Design information was needed for the three drop structures in the project. The decision was made to construct one model which would provide the necessary information. The model was constructed to a scale of 1:21.91 and modelled drop structure No. 3 (Moreland Street) which has a design discharge of 2634 cfs. To provide the necessary information for the other two structures, the model scale could be conveniently changed and the results from the 1:21.91 model extrapolated; or, the existing model could be revised if necessary.
Rochester Combined Surge And Dropshaft Model Studies
(St. Anthony Falls Laboratory, 1983-03) Dahlin, Warren Q.; Wetzel, Joseph M.
The City of Rochester, New York, is developing the combined sewer overflow and abatement plan (CSOAP) to handle sanitary sewage and storm water. The west side system contains 40 dropshafts along a 26 mile long tunnel. The function of these dropshafts is to transport the water from one elevation and energy level to a lower elevation and energy level. At several locations along the tunnel it is proposed to construct surge shafts to attenuate surge pressures in the system. To minimize construction disturbances at the surface, reduce the amount of boring and excavation, and consequently reduce the construction costs, the surge shafts have been combined with conventional dropshafts. These combined surge and dropshaft structures would have dual functions of conveying water from the ground surface to the underground tunnels and relieving surge pressures in the system. Conduits at the ground surface collect the water and convey it to a quarter cylinder elbow which deflects the water 90 degrees into a verticalrectangular shaft. The vertical shaft is located inside and at the upstream side of the surge shaft. One wall of the vertical shaft is slotted to provide for air re-entrainment and also pressure relief in the dropshaft. The surge shaft is a large excavated and lined cylinder which extends from the tunnel level to the ground surface. A boot is attached to the surge shaft just below the dropshaft. Attached to the downstream side of the surge shaft is a deaeration chamber containing a slotted weir, false crown with air slots, and a bellmouth entrance to the exit conduit. An air vent is provided along the downstream side of the surge shaft. The water falling through the elbow and vertical shaft entrains considerable air while gaining kinetic energy. The falling water-air mixture impinges on the floor of the surge shaft. The boot, surge shaft, and deaeration chamber dissipate some of the energy, remove and collect the entrained air, and direct the water at a reduced velocity into the exit conduit. Some of the entrained air is released in the surge shaft and rises directly to the surface. The remaining air rises to the false crown in the deaeration chamber, passes through the air slots into the chamber above, and returns to the upper part of the surge tank through a vent shaft. Part of this return air is then recirculated via the dropshaft air slots and air ramps. A definition sketch (Chart 1) indicates the various shaft components.
Rochester Control Structure 46 Siphon Riser Structure Model Studies
(St. Anthony Falls Laboratory, 1984-12) Dahlin, Warren Q.; Wetzel, Joseph M.; Parker, Gary
The City of Rochester, New York, is developing the Combined Sewer Overflow Abatement Program (CSOAP) to handle sanitary sewage and storm water. The system includes many conventional dropshafts which transport the water collected in surface conduits to the storage and conveyance tunnels at a lower elevation beneath the ground surface. At several locations where surge shafts are near conventional dropshafts the two structures are combined. These combined surge and dropshaft structures have a dual purpose of conveying water from the ground level to the underground tunnels and relieving surge pressures in the system. Located throughout the system are control structures to regulate and divert the flow as required. One of these structures is designated as control structure 46 (CS46). The structure is to be located near the Van Lare treatment plant at the end of the three-mile long siphon tunnel. This is also the downstream terminus of the 22 mile tunnel system. The. primary purpose of the structure is to raise flows coming in through the siphon tunnel and direct them to. a distribution structure at the head of the Van Lare treatment plant. The configuration of the structure in this siphon mode is intended to maximize the transport of sediment entering through the siphon tunnel, up the siphon riser, and through the bifurcation structure. Since it will be difficult to remove all the sediment in the siphon mode, the structure will be operated in the flushing mode. In this mode, supercritical flows will pass straight through the structure and enter a tunnel to the Cross:Irondequoit pumping station. The effectiveness of the structure in transporting sediment is one of the major concerns in the operation of CS46.
Rochester Dropshafts Model Studies
(St. Anthony Falls Laboratory, 1982-04) Wetzel, Joseph M.; Dahlin, Warren Q.
The City of Rochester, New York, is developing the combined sewer overflow and abatement plan (CSOAP) to handle sanitary sewage and storm water. The West Side System contains 40 dropshafts with drop heights varying from 50 ft to 150 ft which are required to handle design discharges from about 150 to 900 cfs. The function of these dropshafts is to trans~ port the water from one elevation and energy level to a lower elevation and energy level. Conduits near the ground surface collect the water and convey it to an elbow which deflects the water 90 degrees into the vertical shaft. The vertical shaft which has a slotted divider wall separating the falling water-air mixture and the released air returning to the surface, terminates in a sump. The sump is a large excavated and lined chamber. The water falling through the elbow and vertical shaft entrains considerable air and gains kinetic energy. The purpose of the sump and deaeration chamber is to dissipate some of the energy, to remove and collect the entrained air, and to direct the water at a reduced velocity into the exit conduit.
Tests Of The Woolley Valve For The James H. Campbell Plant, Unit No. 3
(St. Anthony Falls Laboratory, 1979-11) Ripken, John F.; Dahlin, Warren Q.; Wood, Addison O.; Ferguson, Jeffrey E.
The innovative use of fixed screens to reject solids in condenser cooling water drawn from Lake Michigan has been considered a practical solution for the lake withdrawal system proposed at the James H. Campbell, Unit No.3 Of the Consumer Power Company. The withdrawal point, which is 3,500 feet offshore and approximately 30 feet below the lake surface, is considered relatively free of screen-plugging.solids under normal conditions, but during winter, frazil ice plugging is possible. To assure continued operation under these unusual conditions it was considered necessary to provide the system with an opened water (non-screened) auxiliary intake. This auxiliary function is to be provided by installing a relief valve at the outer or stub end of two of the four header pipes which are to constitu.te the intake system as shown in Fig. 1. These valves are to open and provide .auxiliary intake water whenever screen plugging resulted in a selected level of pressure reduction within the header. The selected level proposed for the valve operation was 12 inches additional headloss. The valve deemed most appropriate for use was a modified version of a Synchro-chek valve made by the W. J. Woolley Company of River Forest, Illinois. The Woolley valve has been marketed for many years as a pump discharge check valve, but its performance under Wave conditions, including 100 year storms, at the proposed site were unknown. In order to clarify the valve .performance it was decided to conduct tests of a 1:4 scale-model valve at the St. Anthony Falls Hydraulic Laboratory of the University of Minnesota. The material which follows describes the Woolley valve, the three part test program (static, steady state flow, and dynamic flow), the test facilities, the test results, and the conclusions and recommendations resulting from the tests.
Wissota Hydro Plant Automatic Spillway Gate Studies Phase I
(St. Anthony Falls Hydraulic Laboratory, 1988-08) Dahlin, Warren Q.; Wetzel, Joseph M.; Stefan, Heinz G.
Northern States Power Company (NSP) is examining various alternatives to modify the automatic spillway gates at the Wissota Hydro Plant on the Chippewa River at Chippewa Falls, Wisconsin. The gates are called "stauwerke" gates. The main purpose of the study is to assure that the automatic spillway gates operate properly during a probable-maximum-flood (PMF) as required by the Federal Energy Re&ulatory Commission (FERC) and the Department of Natural Resources (DNR). The position of the gates must be controllable so that they can be fully lowered or raised with Lake Wissota at its normal elevation of 898.0 ft. The gates must also be fully open during a PMF. The spillway has 13 automatic gates each 64 feet wide in the configuration shown in Fig. 1. Figure 2 shows a photo of the prototype spillway with gate 1 starting at the south abutment on the right. Each gate is connected to a 144.5 ton counterweight through linkages and arms as shown in Fig. 3. Records of openings and closings from 1982 to 1985 show that the gates have operated automatically. Gates 2 through 13 open when the lake elevation is about 0.6 ft above the normal elevation of 898 ft and close when the elevation drops about 0.5 ft below normal. Gate 1 is controlled by a chain hoist and can be pulled down to about 6 ft and used to somewhat control the lake elevation. When the gates open automatically, they open a distance of 3.1 to 3.6 feet. The maximum opening of the gates was 6 feet in the 1941 flood. The 13 gates were expected to be capable of passing 263,000 cfs. With the PMF of 363,000 cfs, other means have to be provided to pass the extra 100,000 cfs. Therefore, the questions are whether or not the gates will operate properly, and if the anticipated flow can be passed. Presently, in the fully lowered position the gates will be 10 feet below pool El. 898 ft. By removing curbs around the gate arm openings, the gates would be horizontal and thus down 10.83 feet. It is not possible to test the prototype gates in the fully lowered position. Therefore, NSP proposed to run field tests on Gate 1 of the Wissota Dam spillway, correlate the results with a physical hydraulic model at the St. Anthony Falls Hydraulic Laboratory, and expand the model studies to test conditions not possible in the prototype.
Wissota Hydro Plant Automatic Spillway Gate Studies Phase II
(St. Anthony Falls Hydraulic Laboratory, 1989-02) Dahlin, Warren Q.; Wetzel, Joseph M.; Stefan, Heinz G.; Simokrot, Bashar
Northern States Power Company (NSP) is examining various alternatives to modify the automatic spillway gates at the Wissota Hydro Plant on the Chippewa River at Chippewa Falls, Wisconsin. The gates are called "stauwerke" gates. The main purpose of the study is to assure that the automatic spillway gates operate properly during a probable-maximum-flood (PMF) as required by the Federal Energy Regulatory Commission (FERC) and the Department of Natural Resources (DNR). The position of the gates must be controllable so that they can be fully lowered or raised with Lake Wissota at its normal elevation of 898.0 ft. The gates must go down for the design flood which currently is the PMF. The spillway has 13 automatic gates, each 64 feet, wide in the configuration shown in Fig. 1. NSP conducted field tests on Gate 1 at the south end of the spillway on April 15, 1988, in which the gate was pulled down to 7.2 ft. It was not possible to test the prototype gates from 7.2 ft down to the fully lowered position of 10.8 ft. During the tests, pulldown forces, piezometric pressures, and water surface profiles were measured. The results of the field tests down to 7.2 ft were correlated with a physical hydraulic model at the St. Anthony Falls Hydraulic Laboratory. These studies are summarized in a previous project report* by the Laboratory. As reported in these studies, good correlation was observed between the field tests and the model tests. The model studies were expanded to include gate positions down to 10.8 ft (the full-down position of the gate), and the results were extrapolated to the prototype. It was concluded from the calculated gate hinge moments that the gates would probably not remain in the full-down position at the higher discharges without additional force being applied.

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