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No description available.

Straipsnyje apibendrinami magistralinių griovių ir jų statinių būklės dviejų metų tyrimų duomenys. Tyrimai atlikti Raseinių, Druskininkų, Kauno ir Šakių rajonuose. Nustatyta, kad didžiausios deformacijos vyksta griovio dugne ir šlaitų papėdėje. Dažniausiai griovys deformuojasi dėl dugne besikaupiančių sąnašų - nevalomas griovys seklėja, lėkštėja jo šlaitai. Tyrimų metu buvo nustatytos šios melioracijos griovių charakteristikos: bendras ilgis, viršaus ir dugno plotis, gylis, sąnašų kiekis griovyje, šlaitų apaugimas krūmais, jų nuolydis, taip pat griovyje esančių drenažo žiočių bei pralaidų būklė. Ištirta 99,44 km melioracijos griovių, 845 drenažo žiotys, 129 pralaidos. Tyrimai atlikti 2006, 2007 metais. Darbo tikslas - įvertinti Raseinių, Druskininkų, Kauno ir Šakių rajonuose esančių melioracijos griovių ir jų statinių esamą būklę. Nustatyta, kad vyraujančios tyrinėtų griovių deformacijos yra šlaitų apaugimas įvairaus tankumo krūmais, dugno uždumblėjimas, vandens augmenijos priaugimas, bebrų užtvankos. Pralaidų esamos deformacijos: netinkama kelio danga, netvarkingi sargšuliai, blogos būklės antgaliai, vamzdžių sandūrose atsiradę tarpai, pralaidose susikaupusios sąnašos. Drenažo žiočių pagrindiniai pažeidimai – užneštos sąnašomis, užaugusios krūmų ir žolių šaknimis, sulūžusios, suskilinėjusios. / Data from two years study of drainage channels are summarized in this paper. The aim of the work was to evaluate statė of drainage channels and its structures in the territory of Raseiniai, Druskininkai, Kaunas and Šakiai districts. It was observed that the majority of deformation‘s processes occur on the bottom and on the slopes of the channels. In most cases channels are deformated due to the deposit, which accumulates on the bottom, and, if no desilting is executed, channel (where a thick layer of silt exists), the channel profile becomes irregular and unstable. It was determined following characteristics of drainage channels: general length, width, slopes pitch, bottom width, depth, amount of deposit in the drainage channels, slopes shrubby and state of channel structures – the outlets of drainage, the water culverts. It was investigated 99,20 km drainage channels, 132 water culverts, 890 drainage outlets in 2006, 2007. The state of drainage channels are bad. The slopes of the drainage channels are overgrown with a medley shrubbery, the drainage channels bottom is silt up. It was found culvert‘s deformations of this nature: low keep paving, bad state of pipe heads, joint tightness, out of order staves and something else. The deformations of drainage outlets are: under deposit, under the sod, the rank scrub and grass roots, broken, breakaway.

Relatively little work has been done to understand how coarse grained sediments behave near culverts. Particularly for embedded culverts, sediment transport must be understood to achieve sustainable culvert designs for aquatic organism passage and peak discharge requirements. Several culvert sites in the Wasatch Mountains of Utah were studied through the spring flood season of 2014. Data obtained from the culvert sites were used to create numerical models with the Sedimentation and River Hydraulics Two-Dimensional model. The field sites and numerical model were used to study deposition of sediments at the entrance to culverts, sediment replenishment inside culverts, and lateral fining within the culvert barrel. Each element of the study was observed in the field. It was shown that the Sedimentation and River Hydraulics Two-Dimensional model is a useful tool to simulate the observed phenomenon of sediment deposition upstream of culverts, sediment replenishment, and lateral fining. Sedimentation and River Hydraulics Two-Dimensional model should be used in culvert design procedures as a means to understand sediment transport conditions.This work documents the first time that deposition of sediments upstream of a culvert and lateral fining within a culvert barrel have been successfully modeled. The work shows that culvert replenishment occurs naturally in many scenarios and should be simulated as part of the culvert design process. The results from this work will be useful for future design guidelines for culvert installations.

Stream crossings are an integral component of forest road systems that provide access for timber harvesting and silvicultural activities. Stream crossings and their associated approaches are often the most critical point of concern for water quality along forest roads. Several types of crossings are used for extracting timber, but limited studies actually compare different types of stream crossings with regard to their effect on water quality. The objectives of this study were to examine four different stream crossing structures: 1) steel bridges, 2) pole bridges (pipe with poles), 3) standard culverts, and 4) re-enforced fords (with GeoWeb or Geotextile) to determine the influence of stream crossing type on water quality and to evaluate erosion associated with stream crossing approaches. We also evaluated each site at four different time intervals to determine if water quality was more affected during different stages of the operations. Prior to operational timber harvests, we identified six replications for each type of crossings (4 fords) and collected data at four time intervals: 1) prior to reopening or installation of crossing, 2) after crossing installation, 3) during harvest operation, and 4) after road closure. Potential erosion rates from approaches to the crossings were estimated by collecting the road/site information necessary to estimate erosion with the Water Erosion Prediction Project for forest roads (WEPP) and the forest version of the Universal Soil Loss Equation (USLE). In-stream water samples were collected at fixed locations above and below each crossing and were evaluated for total dissolved solids (TDS), pH, conductivity, water temperature, and total suspended solids (TSS) or sediment concentration. Steel bridge crossings generally caused the least amount of water quality disturbance. Model-generated estimates of erosion demonstrated that culvert crossings were associated with the highest average soil loss potential. Although steel bridge crossings had the best overall results, pole bridges proved to be a viable option for ephemeral or intermittent streams due to low potential of soil loss. Ford crossings were found to impact water quality indicators, but showed a decrease in total dissolved solids (TDS) after installation, prior to harvest. Overall, the steel skidder bridges were generally the best crossing type, but any of the crossings can be used effectively with minimal impact under specific site conditions and with judicious installation, use, and closure. Road/skid trail location and adherence to existing road grade, water control, cover, and closure best management practices are critical for protection of water quality at stream crossings. / Master of Science

This thesis is focused on explaining the behaviour of population of Aesculapian Snake (Zamenis longissimus) in Poohří region related to a busy road which crosses its area of distribution. To avoid the busy road Aesculapian Snake uses the roads culverts to cross the road safely. Snakes used culverts the most often on July, when their activity culminates. One of the most used culverts was culvert Nr. 2, probably because of its proximity to man-made hatch. Snakes started their activity at 8:00 a.m. and finished at 7:00 p.m. In this study their activity culminates between 4:00 p.m. and 6:00 p.m. and by temperature between 21 - 25°C. None of adults of Aesculapian Snake was detected killed on the road. There were found only juvenile snakes of this species which weren't acquainted yet with local threats.

Hydrological modeling, like runoff modelling for flood prevention, is based on digital elevation models (DEMs). The fact that the DEMs do not represent existing road culverts can lead to considerable hydrological misinterpretations. In order to overcome this limitation, a GIS method was developed to automatically adjust the elevation model, hydrologically enforcing the DEM, so that the results of hydrological modeling accounts for flow through culverts. The hydro-enforced DEM showed to better represent the drainage network than the former DEM when compared with the river map. The topographic wetness index is the most commonly applied topographic index and a good indicator of soil moisture distribution. It has been integrated into many hydrological models and pollution risk indices as well as into the prediction of wetland distribution. Using the hydro-DEM from the previous step and the soil map in conjunction with the TWI, an improved TWI was achieved, namely a soil-topographic wetness index (STI). The linkages between specific soil types and TWI or STI values were analyzed. They revealed a clear linkage between STI values and soil type based on the soil transmissivity (R2=0.77). However, the TWI values showed low correlations to the soil types (R2=0.02). As a specific application, both TWI and STI were tested for the detection of wetlands. Wetlands are important ecosystems which act as buffer zones by filtering pollutants and slowing floodwater. Being able to identify their distribution is important in landscape planning and ecology. A wetland threshold value was determined for each index and their results where compared with the wetland map from the property map (assumed as ground truth) and with the potential wetland area. Finally, a visual validation was performed with the use of an aerial photography. The results showed that the STI performed slightly better than the TWI for the detection of wetlands, detecting 3% more wetlands. The impact of the soil map on the topographic wetness index was therefore determined as positive.

No description available.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / In order to design culverts and bridges, it is necessary to compute an estimate of the design flood. Regionalization of flows by regression analysis is currently the method advocated by the U.S. Geological Survey to provide an estimate of the culvert and bridge design floods. In the regression analysis a set of simultaneous equations is solved for the regression coefficients which will be used to compute a design flood prediction for a construction site. The dependent variables in the set of simultaneous equations are the historical estimates of the design flood computed from the historical records of gaged sites in a region. If a log normal distribution of the annual peak flows is assumed, then the historical estimate of the design flood for site i may be computed by the normal as log Q(d,i) = x(i) + k(d)s(i). However because of the relatively small samples of peak flows commonly used in this problem, this paper shows that the historical estimate should be computed by to log Q(d,i) = X(i) + t(d,n-1) √((n+1)/n) s(i) where t(d,n-1) is obtained from tables of the Student's t. This t-estimate when used as input to the regression analysis provides a more realistic prediction in light of the small sample size, than the estimate yielded by the normal.

The goal of this thesis is to draft a project documentation of the new field road reflecting water retention and accumulation within the complex land consolidation. Territory, suitable for the construction of this new field road, is located in the foothills of the Novohradské hory, about 12 km southeast of the village Trhové Sviny. The chosen location with local names "U hrušky" and "Na 22 hektarech" is located in the eastern part of the cadastral area Dlouhá Stropnice. Proposed practical solution of project documentation of side field road design category P4,0/30 completed with a suitable alternative drainage is based on the theoretical summary of the literature review in this thesis. Other objects - fall culverts and landscaping the surrounding areas are included in the conception of project proposal. An integral part and basis for making the draft was field survey and subsequent analysis of the current status of the affected area.