Geometric models for measuring sediment wedge volume in retention check dams

Check dams act as soil collectors during floods, thus retaining a large amount of sediments. The estimation of the soil volumes stored behind a check dam is a key activity for a proper design of these control works and for evaluation of soil delivery after restoration measures at watershed level. Several topographic techniques have been proposed for this activity, but the sediment wedge mapping tools are complex and time consuming. Conversely, the use of unmanned aerial vehicles (UAVs) has been proposed to support aerophotogrammetric techniques for several survey activities with promising results. However, surveys by UAVs have never applied to calculate the size of the sediment wedge behind check dams that are built in fire-affected watersheds, where soil loss and sediment transport may be high after a wildfire. To fill this gap, this study evaluates the efficiency and efficacy of aerophotogrammetric surveys using UAVs to estimate the volume of the sediments stored behind ten check dams, built as post-fire channel treatment in a forest watershed of Castilla La Mancha (Central Eastern Spain). The results of the aerophotogrammetric technique were compared to traditional topographic surveys using a total station and GNSS/RTK, assumed as reference. The estimation of sediment wedge volume provided by UAVs was more accurate (mean RMSE of 0.432), extensive (density of mapped points of 328 m−2) and quick (two days of fieldwork) compared to surveys using the topographic method (RMSE < 0.04 m, six days of field work and density of mapped points of 0.194 m−2) by the topographic method. The differences in the sediment volume estimated by the two methods were not significant, but the UAV method was more accurate for the larger check dams. Moreover, a significant correlation was observed between the volume estimates provided by the two methods, shown by a coefficient of determination close to 0.98. Overall, these results propose a larger use of the aerial surveys for mapping activities in channels regulated by check dams, such as those built for restoration of fire-affected forest watersheds.

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ALGEBRA OF PREDICATES AND RELATED GEOMETRIC MODELS CREATION IN REGARDS OF UNIFIED STATE EXAM IN INFORMATICS (RUSSIAN EGE)

Informatics in school ◽

10.32517/2221-1993-2019-18-3-40-47 ◽

2019 ◽

pp. 40-47

Author(s):

E. A. Mironchik

Keyword(s):

Geometric Model ◽

Main Idea ◽

Formal Logic ◽

High Complexity ◽

Geometric Models ◽

Complexity Problem ◽

Logical Expression ◽

State Examination

The article discusses the method of solving the task 18 on the Unified State Examination in Informatics (Russian EGE). The main idea of the method is to write the conditions of the problem utilizing the language of formal logic, using elementary predicates. According to the laws of logic the resulting complex logical expression would be transformed into an expression, according to which a geometric model is supposed to be constructed which allows to obtain an answer. The described algorithm does allow high complexity problem to be converted into a simple one.

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Volumetric Representation and Manipulation of Geometric Models

10.21236/ada389494 ◽

2001 ◽

Author(s):

Greg Turk ◽

F. S. Nooruddin ◽

James F. O'Brien ◽

Gary Yngve

Keyword(s):

Geometric Models ◽

Volumetric Representation

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Feasibility of Artificial Groundwater Recharge Structures for Urban and Rural Environment of Ranchi in India using Geospatial Technology

10.21523/gcj3.18020103 ◽

2018 ◽

Vol 2 (1) ◽

pp. 28-42 ◽

Cited By ~ 1

Author(s):

Shanti Mahto ◽

Anuj Kushwaha ◽

Siva Subramanian M. ◽

Nikita Nikita ◽

T. B. N. Singh

Keyword(s):

Artificial Recharge ◽

Groundwater Resources ◽

Remote Sensing Data ◽

Drainage Density ◽

Geographical Information ◽

Rural Environment ◽

Runoff Water ◽

Check Dams ◽

Exploratory Wells ◽

Recharge Structures

Artificial recharge plays a prominent role in the sustainable management of groundwater resources. The study has proposed a methodology to viable artificial recharge structure using geographical information system (GIS) and empirical equation techniques for augmenting groundwater resources in the Ranchi urban and rural area of Ranchi District, Jharkhand. The thematic layers for geomorphology, drainage density, order of streams, runoff and trend has been prepared in the GIS environment using convection and remote sensing data. It has been found that the slope and topographic gradient of Ranchi region is one of the major governing factors, which restricts to hold surface water stagnant. Jumar watershed is found as the most feasible watershed for the construction of check dams/percolation tanks followed by Lower Subarnarekha watershed. Out of 15 deeper exploratory wells, 14 are declining. Harmu watershed is found to be in the worst condition in terms of availability of runoff water. Harmu, Kanke, Bariyatu, Namkum, Doranda, Hinoo and Hatia have found as the most suitable locations for installation of RTRWH within the Ranchi urban area. Based on the available field information, check dams are suggested as the most promising artificial recharge structures for Ranchi rural environment.

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Large-Scale Application of Biofiltration Swale Runoff Management Practices

Water Practice & Technology ◽

10.2166/wpt.2007.049 ◽

2007 ◽

Vol 2 (2) ◽

Author(s):

William C. Lucas

Keyword(s):

Large Scale ◽

Management Practices ◽

Peak Flow ◽

Low Impact Development ◽

Urban Runoff ◽

Management Model ◽

Check Dams ◽

Runoff Reduction ◽

Impervious Area ◽

Hydrologic Responses

Retaining rainfall where it lands is a fundamental benefit of Low Impact Development (LID). The Delaware Urban Runoff Management Model (DURMM) was developed to address the benefits of LID design. DURMM explicitly addresses the benefits of impervious area disconnection as well as swale flow routing that responds to flow retardance changes. Biofiltration swales are an effective LID BMP for treating urban runoff. By adding check dams, the detention storage provided can also reduce peak rates. This presentation explores how the DURMM runoff reduction approach can be integrated with detention routing procedures to project runoff volume and peak flow reductions provided by BMP facilities. This approach has been applied to a 1,200 unit project on 360 hectares located in Delaware, USA. Over 5 km of biofiltration swales have been designed, many of which have stone check dams placed every 30 to 35 meters to provide detention storage. The engineering involved in the design of such facilities uses hydrologic modeling based upon TR-20 routines, as adapted by the DURMM model. The hydraulic approach includes routing of flows through the check dams. This presentation summarizes the hydrological network, presents the hydrologic responses, along with selected hydrographs to demonstrate the potential of design approach.

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Decision with multiple alternatives: Geometric models in higher dimensions — the disk model

Journal of Mathematical Psychology ◽

10.1016/j.jmp.2020.102493 ◽

2021 ◽

Vol 100 ◽

pp. 102493

Author(s):

Keivan Mallahi-Karai ◽

Adele Diederich

Keyword(s):

Higher Dimensions ◽

Disk Model ◽

Geometric Models

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Anyon Networks from Geometric Models of Matter

The Quarterly Journal of Mathematics ◽

10.1093/qmath/haab004 ◽

2021 ◽

Author(s):

Michael Atiyah ◽

Matilde Marcolli

Keyword(s):

Normal Bundle ◽

Present Form ◽

Joint Work ◽

Geometric Models ◽

Tensor Networks

Abstract This paper, completed in its present form by the second author after the first author passed away in 2019, describes an intended continuation of the previous joint work on anyons in geometric models of matter. This part outlines a construction of anyon tensor networks based on four-dimensional orbifold geometries and braid representations associated with surface-braids defined by multisections of the orbifold normal bundle of the surface of orbifold points.

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