Appendix 1. Fishway scale model studies at the University of Oulu during 1991-1995

Fishways have been studied at the University of Oulu, Finland, since the early 1980’s. The first laboratory studies in the beginning of the 1980’s were theoretical, and dealt with head loss in rapidly varying channels (Veijalainen 1985). Head loss was studied with weir, orifice and vertical slot fishway models in different situations. Studies on fishway hydraulics began on a larger scale in the beginning of the 1990"s when a laboratory fishway scale model was constructed (Fig. A1.1). Most of the studies have been reported in Finnish, and some of them in other languages also. All of the reports have not been published.

Most of the scale model studies in the beginning of the 1990’s were conducted for practical purposes. This directly affected the studies and defined the dimensions of the studied structures. In addition, this enabled the comparisons with prototypes. The fishway types studied were mainly Denil and vertical slot fishways. Orifice flows were studied to a smaller extent. The new laboratory scale model was constructed in 1991, originally to improve hydraulic conditions of the Pöyry fishway in the River Siikajoki. Later it has been used in improving other fishways and in studying hydraulics of the vertical slot and Denil fishways. The scale model is also used in the design process of the Isohaara fishway in the River Kemijoki. Studies have also been made for determining discharge rates of fishways (correlation between water levels and discharges) and function of stilling basins. In the scale models, water velocities and water surface profiles were measured and the function of stilling basins in Denil fishways was studied. Also, the significance of tolerances in constructions and the effect of turnings on the functioning of the fishways were studied.

The fishway scale model at the Hydraulic and Water Resources Engineering Laboratory consisted of a transparent polycarbonate flume and a water circulating system. The basic experimental arrangements are shown in Fig. A1.2. Water was pumped from the collection tank into the equalizing flume and conducted from there through the head tank with a well-designed inlet into the model and through the tail tank back into the collection tank. A simple tilting arrangement was used to set the model to slopes of 0-30%. Discharge was controlled by valves. The walls of the flume were made of polycarbonate plates and the baffles of plywood. The flume could be fitted with different kinds of baffles and vanes. At the beginning the model was about 9 meters long, later it was shortened to 5 meters. The inner width of the flume was 0,24 meters.

Discharges were determined by volumetric measurements and, for some of the tests, confirmed afterwards by using a magnetic flow meter. The water depths were measured from the bottom of the flume using a ruler. Time-averaged velocities were measured parallel to the flow by using a current meter with a propeller of 8 mm surrounded by an external ring of 11 mm in diameter. Discharges, water depths, and water velocities were measured several times to minimize the effects of fluctuations and mean values were used in the analyses.

In the model studies on vertical slot fishways, velocities were measured at several water depths in the middle of the slot. Water depths were measured in the middle of the pools. Water depths and velocities in the Denil fishway models were measured at the centerline of the flume, in the middle of the baffles perpendicular to the bottom.

Studies on vertical slot fishways concentrated on the main hydraulic function of the fishway and on slot velocities of different vertical slot fishway types (Fig. A1.3). Studies on Denil fishways concentrated on a structure where the rate b/B (free opening versus total width of the flume) was 0.5. Studies on the arrangements in the upper part of Denil fishway were also carried out by using different angles (40°, 45°, 50°) between the bottom of the flume and the baffles. In addition, the effect of additional baffles was tested by dividing the baffle spacing in half at the three uppermost spaces (Heikkinen 2000). In order to gain information on the hydraulic function of stilling basins between Denil sections, some arrangements were tested (Fig. A1.4).

Flume and baffle dimensions for the studies in Denil fishways were the same in all the experiments (Fig. A1.5). The ratio between the total flume width B and the width of the opening b was B/b = 2, and the ratio between the distance between the baffles a and the width of the opening b was a/b = 1.17. The baffle angle y was 45°. In the studies for the effect of the baffle angle, additional baffle angles y of 40° and 50° were used. The studies were done with different slopes and discharges. Because of the poor pump capacity, only small values of relative water depths could be reached.

The results of the fishway studies have been used in improving conditions for fish migration in several existing fishways and in designing new fishways. One of the first actual fishways in which the results were applied was the Pöyry fishway. The flow conditions in the original fishway were poor and partly unsuitable for fish. Its upper part was especially unsuitable. Based on the studies, the inner parts of the fishway were rearranged, and weirs, vertical slots and vanes were relocated. The structural changes took place in the spring of 1992. After the reparations, the flow conditions improved considerably.

The scale model was also used in the design process of the Isohaara fishway for determining the optimum pool dimensions in vertical slot sections and baffle spacing in Denil sections. It was used to determine the discharge rating curve of the fishway, hydraulic compatibility of different kinds of fishway sections, and the function of stilling basins in the fishway.

Reports and papers

Bärthel J (1996) An overview of fishways and an analysis of experiments on plain Denil fishways. University of Oulu and Technical University of Braunschweig. 78 p. + app. Unpublished

Heikkinen H (2000) Denil-kalatien yläosan virtausolosuhteet pienoismallikokeiden perusteella. (The flow conditions in the upper part of Denil fishway according to the research in a laboratory scale model) 77 p. Unpublished M. Sc. Thesis, Univ Oulu, Hydraulic and Water Resources Engineering laboratory. In Finnish with English abstract.

Kamula R (1995) Interdisciplinary research for successful fish migration improvement. Proc. Int. symposium on fishways "95 in Gifu, Japan Oct. 24-26, 1995. p. 385-390.

Kamula R (1995) Pystyrakokalateiden hydrauliikka ja pienoismallikokeet. Hydraulics and scale model studies of vertical slot fishways. University of Oulu, Hydraulic and Water Resources Engineering Laboratory, series A:61. 75 p. In Finnish with English abstract.

Kamula R & Bärthel J (2000) Effects of modifications on the hydraulics of Denil fishways. Boreal Environment Research No 1/2000, 5: 67-79 .

Kamula R, Laine A & Hooli J (1993) Considering non-salmonid fish in fishway hydraulics. Fish passage policy and technology. Proceedings of a symposium. Sponsored by the Bioengineering section of the American Fisheries Society. Portland, Oregon USA. p. 117-121.

Kamula R, Laine A, Pohjamo T & Hooli J (1992) Siikajoen Pöyryn kalatien tutkimus ja seuranta. Yhteenvetoraportti vuosien 1989-91 tutkimuksista. The research in the Pöyry fishway of the river Siikajoki, Finland. Summary report. University of Oulu, Hydraulic and Water Resources Engineering laboratory, series A:49. 55 p. + app. In Finnish with English abstract.

Laine A & Kamula R (1995) Recent studies on fishways at the University of Oulu, Finland. Sapporo Meeting on "Fishpassage for Northern Countries. Oct. 20th, Sapporo, Japan. Technology Research Center for Riverfront Development. p. 3-18.

Kamula R, Laine A & Hooli J (1995) Climbing up fishways. Aktuumi. Sanomia Oulun yliopistosta, English language issue (4): 12-15.

Laine A, Kamula R, Viitala J, Pohjamo T & Hooli J (1995) Lohi matkalla jokea ylös. Raportti Kemijoen Isohaaran kalatietutkimuksesta. Salmon on the way up. Summary report of the research at the Isohaara fishway in the River Kemijoki, Finland. University of Oulu, Hydraulic and Water Resources Engineering laboratory, series A:63. 42 s. + app. In Finnish with English abstract.

Veijalainen V (1985) Kalaportaan hydraulinen mitoitus. Hydraulics of fishways. University of Oulu, Hydraulic and Water Resources Engineering laboratory, series A:17. 96 p. In Finnish with English abstract.