Due to the endangerment of the June sucker (Chasmistes liorus), the lower two miles of Hobble Creek, Utah has been the focus of several restoration efforts. The portion of the creek between Interstate 15 and Utah Lake has been moved into a more "natural" channel and efforts are now being made to expand restoration to the east side of the freeway. This thesis reports on three different parts of a sedimentological analysis performed on Hobble Creek. The first part is a data set that contains information about the particle size distribution on the bed of Hobble Creek between 400 W and Interstate 15 in Springville, Utah. Particle size distributions were obtained for eleven sub-reaches within the study section. Particle size parameters such as D50 were observed to decrease from an average of 72 mm to 24 mm downstream from the 1650 W crossing and Packard Dam. Streambed armoring was observed along most of the reach. This data set can be used as input for PHABSIM software to determine the location and availability of existing spawning material for June sucker during a range of flows. The second part of this thesis compares predictions from four bed-load transport models to bed-load transport data measured on Hobble Creek. In general, the Meyer-Peter, Muller and Bathurst models overpredicted sediment transport by several orders of magnitude while the Rosgen and Wilcock methods (both calibrated models) were fairly accurate. Design channel dimensions resulting from the bed-load transport predictions diverged as a function of discharge. Once validated, the models developed in this section can be used by design engineers to better understand sediment transport on Hobble Creek. The models may also be applied to other Utah Lake tributaries. The third section of the thesis introduces a detailed survey data set that covers the Hobble Creek floodplain on the shifted section between Interstate 15 and Utah Lake with an approximate 10 foot resolution grid. Water surface elevations at two flows, along with invert, fence, saddles, and other points, are labeled in the survey. A comparison with a survey completed last year did not reveal any significant lateral changes caused by the 2010 spring runoff. Due to the potential importance of the side ponds to June sucker survival, this data set can be used to monitor sedimentation in the side ponds. It may also be used in a GSSHA model to determine the magnitude of flow that is required before each side pond will be connected to the main channel.

No description available.

In this study, a qualitative and comparative investigation on sediment transport equations used in prediction of rserevoir sedimentation is presented. 32 sediment transport equations, which are selected by literature review on sand and gravel size ranges, grouped according to the median particle sizes on which their derivation based. In order to compare these equations computer program DELTA, which is a one dimensional simulation program developed by Graf and Altinakar (1998) for the prediction of delta formation in resrvoirs, is used. Computer simulation is performed within each group of sediment transport equations in order to determine the most suitable equation for corresponding median diameter of sediment particles. 8 of the equations gave simulation results that are in good agreement with average values related to delta deposition extent, height and location in the reservoir. The effects of river slope change and median diameter change on delta deposition also investigated and simulation results are compared with previous model studies.

The fully integrated 3-D, time dependant, hydrodynamic and sediment transport numerical model ECOMSED was used to simulate flow and sediment transport in rivers. ECOMSED was originally developed for large water bodies such as lakes and oceans and solves the primitive equations of RANS along with a second order turbulence model in an orthogonal curvilinear σ- coordinate system. The availability of the model as an open FORTRAN source code made modifications and addition of new models possible. A new bed load transport model was implemented in the code as well as improvements in treatment of river roughness parameterization, bed form effects, and automatic update of flow depth due to bed evolution. The model was applied to 1- km long reach of the River Klarälven, Sweden, where it bifurcates into two west and east channels. The water surface and the flow division in the channels were made in agreement with field data by spatially varying the roughness. However, the spatial distribution of the bed shear stress was not realistic. Improvements were made in the bottom boundary condition to represent the variable effects of bed forms on roughness depending on the flow regime and the flow depth. The improved model realistically reproduced the flow field as well as the sediment transport processes in the river Klarälven. / QC 20101123

En Tunisie, les problèmes des inondations et du transport sédimentaire se posent de façon critique, en particulier au niveau du bassin versant de la Medjerda. En effet, depuis la mise en service du barrage de Sidi Salem (1981) sur le bassin de la Medjerda, des modifications du régime d’écoulement en aval sont apparues sous la forme d’une diminution de la débitance. Cette diminution a eu pour conséquence d’abaisser la capacité de l’Oued à transporter les sédiments et de favoriser leur dépôt. Ceci a provoqué un engraissement du lit, et par conséquent, une occurrence accrue des inondations. Le recours à la modélisation numérique s’avère nécessaire pour mieux comprendre ce risque. Une première partie de ce travail se rapporte à une étude expérimentale menée au niveau d’une installation expérimentale de l’Institut National Agronomique de Tunisie (INAT). L’objectif est de visualiser l’évolution morphologique du fond d’un canal constitué de sable fin sous l’effet d’un écoulement permanent à faible pente. Des simulations numériques ont été effectuées avec différentes lois de transport solide par charriage sur des données expérimentales. L’objectif est de vérifier l’applicabilité de ces lois pour la prédiction de la capacité du transport solide par charriage. Des tests de l’effet du diamètre des matériaux sur la variation du taux de sédiments transportés ont été réalisés. Enfin, des simulations avec différentes formules disponibles sous SISYPHE couplé avec TELEMAC 2D ont été effectuées, pour prédire l’évolution de la couche de sable fin dans le canal. Dans une seconde partie, des simulations de la Medjerda avec des modèles hydrauliques 1D et 2D ont été réalisées. Ces simulations ont concerné les crues récentes pour lesquelles des données sont disponibles, en particulier la crue spectaculaire de janvier 2003, et la crue la plus récente survenue en février 2012. Dans un premier temps, des simulations numériques 1D ont été réalisées via les deux logiciels MIKE 11 et HEC RAS afin de contrôler le comportement de la ligne d’eau lors de ces crues. Dans un second temps, des modélisations hydrauliques bidimensionnelles 2D via le code TELEMAC 2D ont été effectuées ; le but était de déterminer l’étendue de la crue et d’identifier les zones sensibles à l’inondation. La dernière partie de ce travail porte sur l’étude du transport sédimentaire au niveau de la Medjerda. Dans un premier temps, une modélisation unidimensionnelle (1D) du transport solide total lors de la crue de 2003 le long de la moyenne vallée de la Medjerda. Une analyse de l’influence des quantités de matériaux transportés lors des crues sur l’évolution géomorphologique de la Medjerda a été faite. Dans un second temps, une modélisation bidimensionnelle (2D) du transport solide a été réalisée en utilisant SISYPHE couplé avec TELEMAC 2D. Enfin, une nouvelle approche de calcul du transport sédimentaire par charriage, basée sur le modèle d’érosion-déposition de Charru, (2006) a été testée. À l’issue de ce travail, une étude comparative entre les différents résultats obtenus, pour vérifier la validité de ces approches pour le cas de la Medjerda, a été effectuée. / In Tunisia, the problem of floods and sediment transport is critically arising, especially in the Medjerda watershed. Since the construction of Sidi Salem dam, there is a remarkable morphological change, especially on the downstream side. We note a gradual enhancement of the river bed in the downstream direction and therefore, increased occurrence of floods. So, the use of numerical modeling is needed to better understand this risk. An experimental study carried out in a rectangular inclinable flume at the National Institute of Agronomy of Tunisia (INAT). The aim is to visualize the morphological evolution of the channel bottom consisting of fine sand under permanent flow. In the first part, a comparative analysis was conducted between bed load transport rates models with experimental data, in order to test and validate the new bed load model proposed by Lajeunesse et al. (2010), then to check the grain size effect on the sediment transport capacity. After that, we are interested in the study of the morphological evolution in rivers. It was performed through numerical modeling using SISYPHE coupled with TELEMAC 2D. The aim is to analyze the morphological changes in the channel bottom. In the second part, several simulations have been conducted between 1D and 2D hydraulic models. These simulations concerned the recent floods for which data are available, especially the flood in January 2003 and the latest floods occurred in February 2012. Initially, a 1D hydraulic model using the MIKE 11 and HEC RAS software was performed in order to control the behavior of the water line profile during these floods. Secondly, a twodimensional hydraulic model was conducted using the code TELEMAC 2D in order to determine flood extent and to identify flood sensitive areas. The last part of this work will focus on the study of sediment transport at the Medjerda. Initially, we conducted a one-dimensional modeling (1D) of the total sediment transport along the middle valley of the Medjerda river. An analysis of the influence of the amounts of the materials transported by the Medjerda during flood was performed to determine their effects on the river morphological evolution. Secondly, a two-dimensional modeling was performed (2D) of sediment transport using the code SISYPHE coupled with TELEMAC 2D was also performed. We became interested in the study of sediment transport by thrusting only, to see the effect of this transport mode to the morphological evolution. In addition, we opted for a new approach to calculation of bed load sediment transport model based on the erosion -deposition Charru (2006). At the end of this work, a comparative study between the different results to see the validity of this new approach to the case of Medjerda was considered.

This Ph.D. thesis aims to develop numerical models for two-dimensional and three-dimensional shallow water systems over mobile beds. In order to accomplish the goal of this dissertation, the following sub-projects are defined and completed. 1: The first sub-project consists in developing a robust two-dimensional coupled numerical model based on an unstructured mesh, which can simulate rapidly varying flows over an erodible bed involving wet–dry fronts that is a complex yet practically important problem. In this task, the central-upwind scheme is extended to simulation of bed erosion and sediment transport, a modified shallow water system is adopted to improve the model, a wetting and drying scheme is proposed for tracking wet-dry interfaces and stably predict the bed erosion near wet-dry area. The shallow water, sediment transport and bed evolution equations are coupled in the governing system. The proposed model can efficiently track wetting and drying interfaces while preserving stability in simulating the bed erosion near the wet-dry fronts. The additional terms in shallow water equations can improve the accuracy of the simulation when intense sediment-exchange exists; the central-upwind method adopted in the current study shows great accuracy and efficiency compared with other popular solvers; the developed model is robust, efficient and accurate in dealing with various challenging cases. 2: The second sub-project consists in developing a novel numerical scheme for a coupled two-dimensional hyperbolic system consisting of the shallow water equations with friction terms coupled with the equations modeling the sediment transport and bed evolution. The resulting 5*5 hyperbolic system of balance laws is numerically solved using a Godunov-type central-upwind scheme on a triangular grid. A spatially second-order and temporally third-order central-upwind scheme has been derived to discretize the conservative hyperbolic sub-system. However, such schemes need a correct evaluation of local wave speeds to avoid instabilities. To address such an issue, a mathematical result by the Lagrange theorem is used in the proposed scheme. Consequently, a computationally expensive process of finding all of the eigenvalues of the Jacobian matrices is avoided: The upper/lower bounds on the largest/smallest local speeds of propagation are estimated using the Lagrange theorem. In addition, a special discretization of the bed-slope term is proposed to guarantee the well-balanced property of the designed scheme. 3: The third sub-project consists in designing a novel scheme to estimate bed-load fluxes which can produce more accurate results than the previously reported coupled model. Using a pair of local wave speeds different from those used for the flow, a novel wave estimator in conjunction with the central upwind method is proposed and successfully applied to the coupled water-sediment system involving a rapid bed-erosion process. It was demonstrated that, in comparison with the decoupled model, applying the proposed novel scheme to approximate the bed-load fluxes can successfully avoid the numerical oscillations caused by simple and less stable schemes, e.g. simple upwind methods; in comparison with the coupled model using same flux-estimator for both hydrodynamic and morphological systems, the proposed numerical scheme successfully prevents excessive numerical diffusion for prediction of bed evolution. Consequently, the proposed scheme has advantages in terms of accuracy which are shown in several numerical tests. In addition, analytical expressions have been provided for calculating the eigenvalues of the coupled shallow-water-Exner system, which greatly enhances the efficiency of the proposed method. 4: The fourth sub-project consists in developing a three-dimensional numerical model for the simulation of unsteady non-hydrostatic shallow water flows on unstructured grids using the finite volume method. The free surface variations are modeled by a characteristics-based scheme which simulates sub- and super-critical flows. Three-dimensional velocity components are considered in a collocated arrangement with a sigma coordinate system. A special treatment of the pressure term is developed to avoid the water surface oscillations. Convective and diffusive terms are approximated explicitly, and an implicit discretization is used for the pressure term. The unstructured grid in the horizontal direction and the sigma coordinate in the vertical direction facilitate the use of the model in complicated geometries. 5: The fifth sub-project consists in developing a well-balanced three-dimensional shallow water model which is able to simulate shock waves over dry bed. Due to the hydrostatic simplification of the vertical momentum equation, the governing system of equations is not hyperbolic and can not be solved using standard hyperbolic solvers. That is, one can not use a high-order Godunov-type scheme to compute all fluxes through cell-interfaces. This may cause the model to fail in simulations of some unsteady-flows with discontinuities, e.g., dam-break flows and floods. To overcome this difficulty, a novel numerical scheme for the three-dimensional shallow water equations is proposed using a relaxation approach in order to convert the system to a hyperbolic one. Thus, a high-order Godunov-type central-upwind scheme based on the finite volume method can be applied to approximate the numerical fluxes. The proposed model can also preserve the ``lake at rest'' state and positivity of water depth over irregular bottom topographies based on special reconstruction of the corresponding parameters. 6: The sixth sub-project consists in extending the result of the fifth sub-project to development of a three-dimensional numerical model for shallow water flows over mobile beds, which is able to simulate morphological evolutions under shock waves, e.g. dam-break flows. The hydrodynamic model solves the three-dimensional shallow water equations using a finite volume method on prismatic cells in sigma coordinates based on the scheme prposed in sub-project 5. The morphodynamic model solves an Exner equation consisting of bed-load sediment transportation. The performance of the proposed model has been demonstrated by several laboratory experiments of dam-break flows over mobile beds.

The state of Georgia has two large ports that are accessed by way of navigable entrance channels. One of these ports is located in Brunswick, Georgia, and is maintained by the United States Army Corps of Engineers via periodic dredging. Sediments removed from the channel are typically pumped several miles offshore of Brunswick and placed in dredged material mounds, thus removing the sediment from the littoral cycle. This offshore placement, while being the most economically viable method, often negatively impacts the sediment budget of the coastal region and causes erosion downdrift of the channel, specifically along Jekyll Island. Onshore placement of the dredged material is not feasible due to increased associated costs and the high fraction of fines present in the material; thus, nearshore placement is a potentially viable alternative. Nearshore placement could possibly reduce erosion rates and provide protection to property from waves and storms. The USACE initiated a thorough field data collection campaign in 2002 to study the possibility of beneficial placement of dredged material. The author analyzed the existing data to predict the rate and direction of sediment movement away from an existing dredge mound. These predictions are then compared to bathymetric survey data in an effort to validate the results and methodologies used for sediment transport predictions. The ultimate goal is to use the results of this study along with numerical models currently being developed by the Corps to assess the possibility of sediments being transported toward the shore thus re-entering the littoral cycle and providing a benefit to the coast of Georgia.

The main goal of this study is to define the technique to be used to assess the aggradation (by bed load) and degradation (of sediments) of the recessed as well as non-recessed stilling basins of rectangular cross section; when the hydraulic jump occurs in the stilling basin where the submergence coefficient equals 1,05. It consists of two parts, theoretical and experimental. The theoretical part summarizes the related theory on a hydraulic jump, design of a stilling basin, an incipient motion of sediment, an assessment of silting and scouring of the stilling basin. The second part, the actual experiment, led to the determination of the critical values essential for the assessment. For the evaluation, the nondimensional shear stress and the densimetric Froude number were used.

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 / An average of 6 to 13 streamflows from intense summer convective storms occurs annually in the walnut gulch experimental station, 58 square miles in southeastern Arizona. Flows last generally less than 6 hours, and the channels are dry 99 percent of the time. The limiting factors imposed by the geology and geomorphology of the channel to transmission losses of a 6 square mile channel in the station are described. The Precambrian to quaternary geology is outlined, and geomorphology of the channels are described. Volume, porosity and specific yield of alluvium were determined. There is 106 acre-feet of alluvium with a mean specific yield of 28 percent, and a maximum water absorbing capacity of 29 acre-feet or 7 acre-feet per mile of reach. Channel slope is insensitive to changes in geological material beneath it or to changes in flow regime. Channel cross section is highly sensitive to geology and flow regime. Transmission losses were highly correlated to volume of inflow.

<p>Ерозија земљишта је један од најкомплекснијих проблема и уједно један од најподмуклијих човекових непријатеља. Ерозивни процеси постепено разарају и уништавају земљиште, односе хранљиве супстрате и ремете водни режим. Они доводе становништво многих, често пространих области у беду, сиромаштво и миграцију. Због тога, многе привредне гране морају бити увучене у борбу против ерозије земљишта и њених страховитих последица. Ерозија је веома сложена динамичка појава, која зависи од низа фактора чије је диференцирање врло тешко. Испитивање и утврђивање интензитета водне ерозије спада у групу проблема који се не могу свеобухватно решити. Веома је тешко, скоро немогуће, издвојити све факторе, а потом мултиплицирати све те факторе у свим постојећим комбинацијама. Овим радом сагледано је стање ерозије земљишта у сливу Млаве и Пека, односно Хомољу и Звижду, са више аспеката и утврђен низ појава као што су: концентрација растворених минералних материја, процентуално учешће макроелемената у укупној минерализацији, однос минерализације према протицају, укупан годишњи пронос растворених минералних материја, однос специфичне електричне проводљивости и укупне минерализације, износ хемијске евакуације, износ хемијски растворених минералних материја које потичу од стенског комлекса у сливу, утицај геолошког састава на укупну минерализацију воде, њену структуру и специфичну хемијску ерозију, концентрација суспендованог наноса по профилима, однос суспендованог наноса према протицају, укупан годишњи пронос суспендованог наноса као и специфична ерозија, утицај сезонских фактора на концентрацију силта и износ механичке ерозије, утицај геолошког састава на укупан пронос суспендованог наноса, мерење вученог наноса, однос хемијске и механичке ерозије. Хомоље и Звижд највећим делом припадају брдско &ndash; планинском подручју које се одликује водотоковима са релативно великим уздужним падовима, где су углови нагиба од 10 до 40. у Хомољу и Звижду све водотокове карактеришу врло велике разлике између екстремно великих и малих вода, па на неким водотоковима однос максималних и минималних протицаја достиже вредност и хиљаду. Овакав однос између малих и великих вода погодује развоју ерозивних процеса и разарању земљишта. Ерозија у сливу која почиње плувијалном ерозијом, а наставља се денудацијом, доводи до снижавања топографске површине и еродирања&nbsp; земљишта. Таложењем наноса на дну речног корита оно се издиже, што доводи до смањивања&nbsp;овлаженог профила. Велике поплавне воде због тога не могу да протекну тако&nbsp;оплићалим речним коритом, па због тога долази до њиховог изливања, што се&nbsp;манифестује поплавама. Без земљишта остају горњи делови слива, а поплавама,&nbsp;услед таложења вученог и суспендованог наноса на дну речног корита, бивају&nbsp;изложени доњи делови речних токова. Овакав негативан тренд уочен је и у Хомољу&nbsp;и у Звижду који су последњих година све чешће угрожени поплавним водама које&nbsp;причињавају велике штете како пољопривредном земљишту тако и насељима у сливовима Млаве и Пека. С обзиром на чињеницу да у Хомољу и Звижду постоји велики број бујичних токова који носе огромне количине наноса, реално је очекивање да ће се тај нанос акумулирати у средњем и доњем делу сливова Млаве и Пека. Избор хидротехничког метода за истраживање обима и интензитета ерозије у Хомољу и Звижду, као и коришћење методе професора С. Гавриловића у анализи бујичних токова је покушај прецизнијег утврђивања квантитета овог процеса који последњих година има узлазни тренд. Остварење постављених задатака утврђеном методологијом и постигнуће задатих циљева пружа одговор на питање колики је интензитет и обим процеса ерозије у Хомољу и Звижду на годишњем нивоу, по годишњим добима и месецима. Утврђен је степен деловања физичко &ndash; географских фактора који имају утицај на процес ерозије, указано је на обим и врсту примене антиерозивних мера, нарочито у сливовима бујичних токова. Сагледавањем интензитета и обима ерозије у Хомољу и Звижду, односно сливовима Млаве и Пека, успешније ће бити решени водопривредни проблеми који овде постоје.&nbsp;</p> / <p>Erozija zemljišta je jedan od najkompleksnijih problema i ujedno jedan od najpodmuklijih čovekovih neprijatelja. Erozivni procesi postepeno razaraju i uništavaju zemljište, odnose hranljive supstrate i remete vodni režim. Oni dovode stanovništvo mnogih, često prostranih oblasti u bedu, siromaštvo i migraciju. Zbog toga, mnoge privredne grane moraju biti uvučene u borbu protiv erozije zemljišta i njenih strahovitih posledica. Erozija je veoma složena dinamička pojava, koja zavisi od niza faktora čije je diferenciranje vrlo teško. Ispitivanje i utvrđivanje intenziteta vodne erozije spada u grupu problema koji se ne mogu sveobuhvatno rešiti. Veoma je teško, skoro nemoguće, izdvojiti sve faktore, a potom multiplicirati sve te faktore u svim postojećim kombinacijama. Ovim radom sagledano je stanje erozije zemljišta u slivu Mlave i Peka, odnosno Homolju i Zviždu, sa više aspekata i utvrđen niz pojava kao što su: koncentracija rastvorenih mineralnih materija, procentualno učešće makroelemenata u ukupnoj mineralizaciji, odnos mineralizacije prema proticaju, ukupan godišnji pronos rastvorenih mineralnih materija, odnos specifične električne provodljivosti i ukupne mineralizacije, iznos hemijske evakuacije, iznos hemijski rastvorenih mineralnih materija koje potiču od stenskog komleksa u slivu, uticaj geološkog sastava na ukupnu mineralizaciju vode, njenu strukturu i specifičnu hemijsku eroziju, koncentracija suspendovanog nanosa po profilima, odnos suspendovanog nanosa prema proticaju, ukupan godišnji pronos suspendovanog nanosa kao i specifična erozija, uticaj sezonskih faktora na koncentraciju silta i iznos mehaničke erozije, uticaj geološkog sastava na ukupan pronos suspendovanog nanosa, merenje vučenog nanosa, odnos hemijske i mehaničke erozije. Homolje i Zvižd najvećim delom pripadaju brdsko &ndash; planinskom području koje se odlikuje vodotokovima sa relativno velikim uzdužnim padovima, gde su uglovi nagiba od 10 do 40. u Homolju i Zviždu sve vodotokove karakterišu vrlo velike razlike između ekstremno velikih i malih voda, pa na nekim vodotokovima odnos maksimalnih i minimalnih proticaja dostiže vrednost i hiljadu. Ovakav odnos između malih i velikih voda pogoduje razvoju erozivnih procesa i razaranju zemljišta. Erozija u slivu koja počinje pluvijalnom erozijom, a nastavlja se denudacijom, dovodi do snižavanja topografske površine i erodiranja&nbsp; zemljišta. Taloženjem nanosa na dnu rečnog korita ono se izdiže, što dovodi do smanjivanja&nbsp;ovlaženog profila. Velike poplavne vode zbog toga ne mogu da proteknu tako&nbsp;oplićalim rečnim koritom, pa zbog toga dolazi do njihovog izlivanja, što se&nbsp;manifestuje poplavama. Bez zemljišta ostaju gornji delovi sliva, a poplavama,&nbsp;usled taloženja vučenog i suspendovanog nanosa na dnu rečnog korita, bivaju&nbsp;izloženi donji delovi rečnih tokova. Ovakav negativan trend uočen je i u Homolju&nbsp;i u Zviždu koji su poslednjih godina sve češće ugroženi poplavnim vodama koje&nbsp;pričinjavaju velike štete kako poljoprivrednom zemljištu tako i naseljima u slivovima Mlave i Peka. S obzirom na činjenicu da u Homolju i Zviždu postoji veliki broj bujičnih tokova koji nose ogromne količine nanosa, realno je očekivanje da će se taj nanos akumulirati u srednjem i donjem delu slivova Mlave i Peka. Izbor hidrotehničkog metoda za istraživanje obima i intenziteta erozije u Homolju i Zviždu, kao i korišćenje metode profesora S. Gavrilovića u analizi bujičnih tokova je pokušaj preciznijeg utvrđivanja kvantiteta ovog procesa koji poslednjih godina ima uzlazni trend. Ostvarenje postavljenih zadataka utvrđenom metodologijom i postignuće zadatih ciljeva pruža odgovor na pitanje koliki je intenzitet i obim procesa erozije u Homolju i Zviždu na godišnjem nivou, po godišnjim dobima i mesecima. Utvrđen je stepen delovanja fizičko &ndash; geografskih faktora koji imaju uticaj na proces erozije, ukazano je na obim i vrstu primene antierozivnih mera, naročito u slivovima bujičnih tokova. Sagledavanjem intenziteta i obima erozije u Homolju i Zviždu, odnosno slivovima Mlave i Peka, uspešnije će biti rešeni vodoprivredni problemi koji ovde postoje.&nbsp;</p> / <p>The abstract has been processed with OCR optical text recognition technology.</p><p>Soil erosion is one of the most complex problems and at the same time one of the most insidious of human enemies. Erosion processes gradually destroy the land, carry away nutritional substrates and disrupt the water regime. They drive many people, often from large areas, to misery and poverty, and cause migration. Therefore, many industries have to be included into the fight against soil erosion and its terrible consequences. Erosion is a very complex and dynamic phenomenon that relies on many factors which are hard to define. Differentiating and determining the intensity of water erosion are among the problems that cannot be comprehensively solved. It is very difficult, almost impossible, to extract all the factors and then multiply all these factors in every possible combination. This paper looks at the situation with soil erosion in the water basins of the rivers Mlava and Pek respectively, that is, in the areas of Homolje and Zvižd, from various aspects, and identifies a series of phenomena such as concentration of dissolved minerals, percentage of macroelements in the total mineralization, the relationship of mineralization to the flow, the total annual transport of dissolved minerals, the ratio of the specific electrical conductivity and total mineralization, the amount of chemical evacuation, the amount of chemically dissolved minerals that come from the rock complex in the basin, the impact of geological composition on the total mineralization of water, its structure and specific chemical erosion, suspended sediment concentration by profiles, the effect of suspended sediment on the flow, the total annual transport of suspended sediment as well as the specific erosion, the impact of seasonal factors on the concentration of silt and the amount of mechanical erosion, the impact of geological composition on the total transport of suspended sediment, bed load measurement, the ratio of chemical and mechanical erosion. Homolje and Zvižd are mostly hilly and mountainous areas characterized by water streams with relatively large vertical drops where the pitch angles may vary from 10&deg; to 40&deg;. In Homolje and Zvižd all the waterways are characterized by very large differences between extremely high and low water, reaching the value of a thousand in some points. This kind of a ratio between high and low waters favors the development of erosion processes and the destruction of land. Erosion in a basin starts with a pluvial erosion and continues with denudation, causing the lowering of the topographic surface and soil erosion. When the sediment deposits at the bottom of the river bed, the bed rises, leading to a reduction of the humidified profile. Therefore great floodwater cannot pass through such a shallow riverbed, which leads to its discharge and causes a flood. The upper parts of the basin lose land, and the lower parts of the basin become exposed to floods due to the deposition of bed load and suspended sediment at the bottom of the riverbed. This negative trend has been observed both in Homolje and Zviždi which in recent years have become increasingly threatened by flood waters which cause great damage to agricultural land and settlements in the basins of the rivers Mlava and Pek. Considering the fact that Homolje and Zvižd there is a large number of torrential streams that carry huge amounts of sediment, it is reasonable to expect the sediment to accumulate in the middle and lower parts of the basins of Mlava and Pek. The selection of the hydrotechnical method to explore the scope and intensity of erosion in Homolje and Zvižd, and the use of Professor S. Gavrilović&rsquo;s method in the analysis of torrential flows is an attempt to determine more precisely the quantity of this process with an increasing trend in recent years. Fulfillment of tasks and achievement of objectives through suggested methodology and achievement of objectives provides the answer to the question of intensity and extent of erosion in Homolje and Zvižd on an annual basis, according to seasons and months. The paper has determined the degree of impact of physical and geographic factors on the erosion process, and has pointed to the scope and type of application anti-erosion measures, especially in watersheds with torrential flows. If we manage to comprehend the intensity and extent of erosion in Homolje and Zvižd, that is, in the basins of Mlava and Pek, we will be able to solve the existing water management problems more successfully.</p>