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According to Department of Fisheries and Oceans Canada, culverts and other stream crossings must be designed to ensure fish passage. The effects of ice processes on these fish passage designs have never been assessed. This study is the first to document ice processes on two different types of fish passage designs (streambed simulation and baffle). The results of a 2 year field monitoring campaign showed that the culvert simulating the streambed retains a natural ice regime, i.e., both freeze-up and break-up occurred concurrently with the rest of the stream, while multiple supercooling events were recorded under a thin ice cover. As for the culvert with baffles, it was observed that the ice cover formed earlier and stayed longer in the culvert, which can create a barrier for fish transiting through them. [ABSTRACT FROM AUTHOR]

Box culverts are utilized in situations where natural stream flow intersects with roads and railway lines. This research utilizes a digital elevation model and the water Modeling System software to assess the catchment area of the primary valley and identify the factors contributing to flooding in Qoshtapa City. The study involves an analysis of the existing culvert and generated the necessary data for the design of a new culvert. Despite the presence of the existing culvert, floodwater levels rose to over 1 m above the roadway elevation of Erbil-Kirkuk during the last flood event in 2021–2022. The research collected hydrological and climatic data for the study area, conducted soil type analysis using the Harmonized World Soil Database software, and performed hydraulic calculations to estimate the maximum flood discharge of the valley using the Hydrological Engineering Center-Hydrological Modeling System software for flood return periods of 50, 100, and 200 years, for design, to select the best economic alternative. The new culvert design was executed using Bentley Culvert Master software to ensure that floodwaters can flow through the culvert without rising to street level. The results indicated that the new culvert design surpasses the capacity of the existing one. The results show that the best economic alternative hydraulic design is the first alternative capacity of 201 m3/s of a 100-year return period; the new design cross-section area of the culvert is 52.5 m2.

Box culverts are utilized in situations where natural stream flow intersects with roads and railway lines. This research utilizes a digital elevation model and the water Modeling System software to assess the catchment area of the primary valley and identify the factors contributing to flooding in Qoshtapa City. The study involves an analysis of the existing culvert and generated the necessary data for the design of a new culvert. Despite the presence of the existing culvert, floodwater levels rose to over 1 m above the roadway elevation of Erbil-Kirkuk during the last flood event in 2021–2022. The research collected hydrological and climatic data for the study area, conducted soil type analysis using the Harmonized World Soil Database software, and performed hydraulic calculations to estimate the maximum flood discharge of the valley using the Hydrological Engineering Center-Hydrological Modeling System software for flood return periods of 50, 100, and 200 years, for design, to select the best economic alternative. The new culvert design was executed using Bentley Culvert Master software to ensure that floodwaters can flow through the culvert without rising to street level. The results indicated that the new culvert design surpasses the capacity of the existing one. The results show that the best economic alternative hydraulic design is the first alternative capacity of 201 m³/s of a 100-year return period; the new design cross-section area of the culvert is 52.5 m². [ABSTRACT FROM AUTHOR]

The construction of a new CFPP in Indonesia, which was located next to three existing power plants and utilized an existing discharge channel, faced the problem of insufficient capacity of the existing discharge channel to deliver water to four power plants. The problem occurred not only because of the overcapacity of the cooling water flow proposed by the new CFPP but also because of the small size of the culvert located in the discharge channel. This paper discusses several methods to overcome this problem by enlarging the culvert area or by removing the culvert from the channel and replacing it with a bridge. A hydraulic study was investigated using the HEC-RAS software by utilizing inputs obtained from the existing channel geometry and flow measurement data. It was found that additional culverts on both sides with a size of 2 m x 4 m and 3 m x 1 m could reduce the water level by 1.12 m and 0.39 m, respectively. Meanwhile, removing the culvert provided a significant water level reduction of 1.39 m. Enlarging the culvert was chosen as the solution to the discharge channel capacity issue since removing the culvert would require temporarily closing the channel during construction and stopping the operation of the existing power plant. [ABSTRACT FROM AUTHOR]

This paper presents the findings of a study into how different inlet designs for stormwater culverts increase the discharge rate. The objective of the study was to develop improved inlet designs that could be retro-fitted to existing stormwater culvert structures in order to increase discharge capacity and allow for changing rainfall patterns and severe weather events that are expected as a consequence of climate change. Three different chamfer angles and a rounded corner were simulated with the software ANSYS Fluent, each of the shapes tested in five different sizes. Rounded and 45 ∘ chamfers at the inlet edge performed best, significantly increasing the flow rate, though the size of the configurations was a critical factor. Inlet angles of 30 ∘ and 60 ∘ caused greater turbulence in the simulations than did 45 ∘ and the rounded corner. The best performing shape of the inlet, the rounded corner, was tested in an experimental flume. The flume flow experiment showed that the optimal inlet configuration, a rounded inlet (radius = 1/5 culvert width) improved the flow rate by up to 20% under submerged inlet control conditions.

Urbanisation creates the need for engineered hydraulic structures in catchments, floodplains and watercourses. These include piped and open-channel drainage networks, flood control systems and waterway crossings such as culverts and bridges. During larger storm events, debris and other material located higher in the catchment can be mobilised and transported towards these hydraulic structures creating the potential for blockages. This debris is often trapped by the hydraulic structures, causing partial or full blockage which can reduce the flow capacity of the structure. This may cause upstream flooding during high intensity rainfall events. This study investigated the debris transport behaviour in a natural channel. A model of an existing catchment and culvert system in Australia was build based on Froude similitude scaling. Different sized twigs were used to replicate natural debris of various sizes. The experimental results demonstrated that the mobility of debris during rainfall events was dependent on a range of factors including stream depth and width, the size and availability of debris, and on the condition of the riparian vegetation within the catchment. This could have significant implications for culvert design and maintenance procedures. [ABSTRACT FROM AUTHOR]

Stream simulation has become an increasingly common culvert design method around the world. It is based on the assumption that geologic and hydraulic conditions in natural channels define passage characteristics for migrating fish and that water crossing structures that imitate these conditions can then achieve those same passage characteristics. This study expands on an initial evaluation of 19 culverts in 2003 to 50 culverts and includes methods and analyses comparing hydraulic characteristics based on cross sections, profile variation, and bed texture between each culvert and its paired reference reach situated in an adjacent section of the natural channel of each stream. Taken as a group, these culverts simulate bed texture, 100-year recurrence interval flood velocity and 2-year flood width but did not simulate thalweg complexity or other hydraulic metrics. Culvert span, relative to the bankfull width of the stream, does not by itself determine whether the culvert simulates the reference reach. Of the 50 culverts, many of which experienced record floods, only one showed significant bed degradation. [ABSTRACT FROM AUTHOR]

In this study, hydraulic bulking was evaluated based on a physiographic and hydrologic perspective of eight small semiarid watersheds within New Mexico. Attributes related to drainage and sediment load were characterized using an ArcGIS (Esri, Redlands California) approach. An in-depth terrain analysis coupled with land cover, precipitation, soil, and hydrography raster data sets provided characterization of key watershed attributes. Associated raster maps of derived attributes were generated, in addition to watershed peak flow and runoff volume based on a 100-year, 24-h precipitation. With this composite data, a hydraulic bulking factor, or ratio of total flow with sediments to clean water flow, was estimated. Bulking factors ranged from 1.01 to 1.65. Significant trends and correlations were evident and supported by literature, thus offering the potential for development of a statewide bulking factor map and ultimately an engineering design factor for drainage structures. A procedure for estimating this bulking factor is presented; however, field verification of the proposed methodology is needed. [ABSTRACT FROM AUTHOR]

This paper presents the findings of a study into how different inlet designs for stormwater culverts increase the discharge rate. The objective of the study was to develop improved inlet designs that could be retro-fitted to existing stormwater culvert structures in order to increase discharge capacity and allow for changing rainfall patterns and severe weather events that are expected as a consequence of climate change. Three different chamfer angles and a rounded corner were simulated with the software ANSYS Fluent, each of the shapes tested in five different sizes. Rounded and 45 ∘ chamfers at the inlet edge performed best, significantly increasing the flow rate, though the size of the configurations was a critical factor. Inlet angles of 30 ∘ and 60 ∘ caused greater turbulence in the simulations than did 45 ∘ and the rounded corner. The best performing shape of the inlet, the rounded corner, was tested in an experimental flume. The flume flow experiment showed that the optimal inlet configuration, a rounded inlet (radius = 1/5 culvert width) improved the flow rate by up to 20% under submerged inlet control conditions. [ABSTRACT FROM AUTHOR]

Worldwide declines in riverine fish abundance and diversity have been linked to the fragmentation of aquatic habitats through the installation of instream structures (e.g. culverts, dams, weirs and barrages). Restoring riverine connectivity can be achieved by remediating structures impeding fish movements by, for example, replacing smooth substrates of pipe culverts with naturalistic substrates (i.e. river stones; culvert roughening). However, empirical evaluations of the efficacy of such remediation efforts are often lacking despite the high economic cost. We assessed the effectiveness of substrate roughening in improving fish swimming performance and linked this to estimates of upstream passage success. Critical swimming speeds ( U crit ) of two small-bodied fish, purple-spotted gudgeon ( Mogurnda adspersa ; 7.7-11.6 cm total length, BL) and crimson-spotted rainbowfish ( Melanotaenia duboulayi ; 4.2-8.7 cm BL) were examined. Swimming trials were conducted in a hydraulic flume fitted with either a smooth acrylic substrate (control) or a rough substrate with fixed river stones. Swimming performance was improved on the rough compared to the smooth substrate, with Mo. adspersa ( U crit-smooth = 0.28 ± 0.0 m s -1 , 2.89 ± 0.1 BL s -1 , U crit-rough = 0.36 ± 0.02 m s -1 , 3.66 ± 0.22 BL s -1 , mean ± s.e) and Me. duboulayi ( U crit-smooth = 0.46 ± 0.01 m s -1 , 7.79 ± 0.33 BL s -1 ; U crit-rough = = 0.55 ± 0.03 m s -1 , 9.83 ± 0.67 BL s -1 , mean ± s.e.) both experiencing a 26% increase in relative U crit . Traversable water velocity models predicted maximum water speeds allowing successful upstream passage of both species to substantially increase following roughening remediation. Together these findings suggest culvert roughening may be a solution which allows hydraulic efficiency goals to be met, without compromising fish passage.