Fiskvägar kan anläggas i anslutning till dammar för att överkomma de hinder som dammarna utgör mot migrerande fisk. En av de mest önskvärda lösningar som finns för detta är att anlägga naturlika fiskvägar, vilka har som syfte att efterlikna ett naturligt vattendrag. Ofta har dock dessa planerats för dåligt med avseende på exempelvis lutning och placering av ingången för att de ska kunna fungera riktigt effektivt. På grund av detta finns det behov av omfattande studier av topografi och kartering av området innan en fiskväg anläggs. I det här arbetet används topografin och de geografiska förutsättningarna för att studera möjliga sträckningar på en naturlik fiskväg förbi Strömdalens kraftverk i Gävle som en del av det fiskvandringsprojekt som Länsstyrelsen Gävleborg driver. I arbetet byggs en höjdmodell upp med hjälp av data från LiDAR (Light Detection and Ranging) och genom topografisk mätning, där mätpunkter från Global Navigation Satellite System (GNSS) och Totalstation används för att korrigera LiDAR-modellen över visst område. Det går att förbättra kvaliteten på modellen avsevärt med korrigering av LiDAR-data genom jämförelser mot mätpunkter. Studien har visat att det går att uppnå en noggrannhet som är bättre än en decimeter överlag i modellen, med vissa lokala variationer. Dessa variationer visar sig i större osäkerhet i mera svårdefinierad terräng, som strandkanter eller där terrängen visar stor variation. Studierna har också visat att i områden där det finns många mätpunkter är kvaliteten bättre än i områden där det är glest mellan punkterna. Bottentopografier hade varit mycket önskvärt att mäta eftersom dessa behövs vid fiskvägsplanering, men det var dessvärre vid tidpunkten för fältarbetet inte möjligt att utföra några mätningar i vattnet på grund av högt vattenstånd. I studien har också den uppbyggda höjdmodellen använts för att hitta metoder att analysera och visualisera olika förslag på naturlika fiskvägar. Studierna har visat att topografin är en viktig faktor inom planeringen på grund av fiskvägars lutningskrav. För att uppnå den önskade medellutningen måste i många fall topografin modifieras ordentligt och detta har visat sig vara ett problem vid Strömdalens kraftverk. Genom att utnyttja 3D-modellering går det se detta ur ett annat perspektiv och då framkommer också svårigheterna med att anpassa fiskvägen till terrängen bättre. / Dams are obstacles for migrating fish species and a solution for this problem is to construct fish bypasses. One of the most desirable solutions for this is nature-like fish passages which is a solution where the bypass is looking like a real stream. However, because these passages have been planned poorly considering slope and placing of the entrance, they have not been that effective. Because of that, studies in topography and mapping of the area are important before a fish passage is constructed. In this study the topographic and geographic criteria are used to study possible paths where the fish passage can be constructed. This is done around Strömdalens kraftverk, close to the central parts of Gävle as part of the fish migration project of Länsstyrelsen in Gävleborg. In the study, Digital Elevation Models (DEM) is produced by data from Light Detection and Ranging (LiDAR) and by performing a topographic survey using Global Navitation Satellite System (GNSS) and total station in this area. The LiDAR data are corrected by those survey points by comparing them to the uncorrected LiDAR model. By doing that and also including the survey points, the performance of the model was greatly improved. In general the surveyed area is shown to have an uncertainty lower than a decimeter, but with local variations. Those variations are higher in more complex terrain, for example around shorelines and in areas with high terrain variation. The study has also shown that the uncertainty is lower in areas where many points have been surveyed. Bathymetric data are of great importance. However, by the time of the field survey, it was impossible to perform any survey in the water because of a high water level. Different suggestions on nature-like fish paths have also been analyzed and visualized by using a produced DEM. The studies have shown that topography is a very important factor because of the slope criteria for those fish passages. To reach the desired mean slope the topography has to be greatly modified, which is a major issue near Strömdalens kraftverk. By using 3D models it is possible to see that from a different perspective and it's easier to see the difficulties to adapt the fish passage to the terrain.

No description available.

Smallmouth bass (Micropterus dolomieu) were collected from a reach of the James River, Virginia undergoing American shad (Alosa sapidissima) restoration and fish passage projects. Diet and growth of these specimens were compared to specimens collected prior (1987-1990) to American shad restoration and fish passage. The Piedmont James River was stocked with >5 million American shad larvae annually since 1995 and was re-opened to migratory fish in 1999. Mean lengths-at-age (ages 1-4) were back-calculated from scales and compared using the Mann-Whitney Test. Smallmouth bass collected in 2002 had a significantly lower mean length-at-age for age 2 specimens compared to 1987-1989 smallmouth bass (P=0.04). Stomach contents were placed into four major categories (fish, crayfish, aquatic insects, terrestrial insects) and compared using Schoener's Diet Overlap Index. Schoener's Index produced a score of 0.94; indicating very high diet overlap. In 2002, Centrachidae was the dominant fish prey family and redbreast sunfish (Lepomis auritus) was the dominant species. American shad was not observed in stomach samples during 1987-1990, but was the second most common fish species prey species identified in 2002. Recovery of American shad from smallmouth bass indicates smallmouth bass are utilizing forage produced by restoration stockings. No semi-migratory fish species using new fish passage structures were recovered fiom smallmouth bass stomachs. Fish prey was measured by weight, number of items, and by occurrence; and placed in six family categories for comparison. Schoener's Index produced scores ranging from 0.26 for prey weight to 0.40 for prey occurrence, indicating low fish prey diet overlap. These data indicate that smallmouth bass are utilizing new forage resulting from restoration activities, but growth rates have not changed significantly. Smallmouth bass may not be forage-limited in the study area.

River restoration is believed to have the greatest chance of success when action is considered in the broader context of the riverscape. However, methods are lacking to fully integrate systemic connectivity into decision-making. Optimisation, a method of prioritisation, is capable of accounting for longitudinal connectivity, spatial interdependence, and cumulative effects of anthropogenic barriers such as dams and culverts. In addition, optimisation can help ensure that limited restoration funds are efficiently allocated. Despite these advantages, it remains under-employed. I present optimisation models for maximising connectivity within a river network (i.e., undirected connectivity) and connectivity between the network and its outflow (i.e., directed connectivity) and demonstrate their application on three river networks in Nova Scotia, Canada. Non-additive cumulative effects of barriers and key budget thresholds that yielded better returns on investment were observed. The methods and models address current challenges in implementation of the optimisation approach to systematic river restoration planning. / Master's Thesis

Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.

Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.

An abundant Paddlefish Polyodon spathula population exists in a 0.8 ha pool below a water control structure at Sam D. Hamilton Noxubee National Wildlife Refuge, Mississippi. Managers were concerned that regulated flows from the structure were causing an ecological trap if Paddlefish were being attracted from the larger river downstream during the spawning period, but conditions were not suitable to facilitate reproduction. Between February 2016 to April 2018, 117 Paddlefish were identified and daily abundance was estimated between 18 and 75 fish. Telemetry study of 59 fish suggests a mixed population structure where some remain in the pool year-round and other emigrate seasonally, cued by rising spring discharge and water temperature. Reproduction was not documented which suggests a critical component needed for spawning may be missing, at least during this study. Therefore, given the need to remove Paddlefish from the pool, translocation and flow releases may be effective management strategies.

Nature-like fish passes have been designed with the intent to re-connect river corridors and provide passage for all species occurring in a system. Nature-like fish pass designs have been constructed in Europe and elsewhere with some success, but performance of these designs has not been evaluated for North American species. Re-establishing passage for adult anadromous clupeids to their spawning areas is critical considering their recent dramatic population declines. Two nature-like fish pass designs in New England were evaluated for passage of anadromous adult alewives (Alosa pseudoharengus) using passive integrated transponder (PIT) telemetry and showed differing results. At Town Brook in Plymouth, Massachusetts the 32 m long perturbation boulder rock ramp with a 1:24 slope passed 94% of attempting fish with most ascending in under 22 minutes. At East River in Guilford, Connecticut the 48 m long steppool bypass design with a 1:14 slope passed only 40% of attempting fish with a median transit time of 75 minutes. Two technical fishway designs at the field sites were also evaluated and showed contrasting performance. At Town Brook a 14 m long 1:7 slope pool and weir fishway exhibited attraction and passage deficiencies. At East River two 3.05 m long steeppass fishways both passed the majority of attempting fish but one steeppass fishway may have had poor attraction efficiency. At both sites tagged fish passed rapidly downstream through the fish passes after spawning. Nature like fish pass designs are suitable for the passage of alewife but further evaluations are required to more precisely identify the influence of vertical drop per pool and specific local hydraulics on behaviors and passage performance for this species.

The Seattle District wants to better manage the Ballard Locks and structures along the Lake Washington Ship Canal (LWSC) in a way that will maintain the environmental sustainability and biodiversity in the area. Due to strict salt water intrusion regulations in the LWSC, the Seattle District is working on upgrading their management practices such that they will resolve two inter-related problems. First, to improve the fish passage conditions for migrating salmon; and second, to learn how to better manage the salt wedge that forms and intrudes upstream. Based on the hydrodynamic and water quality results that are produced by this research, the Engineer Research and Development Center (ERDC) Portland Office will use their Eulerian-Lagrangian-Agent-Model (ELAM) to analyze fish patterns, looking for the most beneficial management schemes that assist salmon in migrating upstream. This research implemented CFD engineering techniques to help better understand the effectiveness of the hydraulic structures in the area, as well as come up with management practices that both mitigate the salt water intrusion from Puget Sound, and improve the migrating passages for salmon.

Loss of connectivity in riverine systems due to construction of hydropower dams has resulted in a worldwide decline of anadromous salmonid species such as Atlantic salmon (Salmo salar L.) and sea trout (Salmo trutta L.). The future of these species depend on the presence of available spawning habitat in freshwater river systems. Modern research and mitigation efforts mainly focus on ensuring a successful upstream passage past dams e.g. fish ladders. Atlantic salmon and sea trout are iteroparous, and are thus able to spawn repeatedly during their lifetime. Individuals surviving upstream migration and spawning generally face a hazardous journey back to their marine feeding grounds. In this large scale natural field study I evaluate the possibility of using a bubble barrier as a non-physical structure to guide downstream migrating kelt past the turbines at a large hydropower station in northern Sweden. Results from this study clearly show that kelt effectively can be diverted using a bubble barrier in daylight conditions with a mean water velocity of 1.1 m s-1 (p=0,01). From a fishway managers perspective, increasing survival of salmonid kelt is a substantial step towards achieving a viable population with increased numbers of repeat spawners and large individuals. This study presents new results in a sparsely explored subject; the diversion of post-spawn salmonid migrants using non-physical barriers.