scholarly journals Measuring ephemeral gully erosion rates and topographical thresholds in an urban watershed using unmanned aerial systems and structure from motion photogrammetric techniques

2018 ◽  
Vol 29 (6) ◽  
pp. 1896-1905 ◽  
Author(s):  
Napoleon Gudino-Elizondo ◽  
Trent W. Biggs ◽  
Carlos Castillo ◽  
Ronald L. Bingner ◽  
Eddy J. Langendoen ◽  
...  
Keyword(s):  
Structure From Motion ◽  
Gully Erosion ◽  
Unmanned Aerial Systems ◽  
Urban Watershed ◽  
Erosion Rates ◽  
Ephemeral Gully ◽  
Aerial Systems

Analysis of ephemeral gully erosion in small agricultural watersheds in Iowa (USA)

2020 ◽  
Author(s):  
Eduardo Luquin ◽  
Richard M. Cruse ◽  
Karl R. Gesch ◽  
Matthew J. Helmers ◽  
Henrique G. Momm ◽  
...  
Keyword(s):  
Cross Section ◽  
The United States ◽  
Gully Erosion ◽  
Soil Productivity ◽  
Time And Space ◽  
Erosion Rates ◽  
No Till ◽  
Ephemeral Gully ◽  
Ephemeral Gullies ◽  
Over Time

<p>Ephemeral gullies (EG) are linear erosion features located in swales where surface and/or subsurface runoff concentrate during or immediately after rainfall events. As its name states, EGs are temporary because they are easily filled by conventional machinery, but when filled they reform if the area is not appropriately managed. Downstream water quality issues and decreased soil productivity are the main environmental impacts. EGs are frequently identified as (the most) relevant sediment sources in agricultural areas but their dimensions and particular contribution to the total erosion under different temporal, spatial, climate and land use condition is still unknown. Therefore, the objective of this study is to obtain ephemeral gully erosion rates and estimate the main morphological characteristics of the ephemeral gullies (width, length and depth) and their evolution both in relation to time and position on the landscape.</p><p>The studied EGs, B6 with a 0.94 ha watershed and I3 with a 0.95 ha watershed formed in two fields located in the Walnut Creek watershed, Iowa (US). The field-sized watersheds are less than 1.5 Km apart and have similar topography and soils. The cropping system consists of a two-year corn-soybean rotation managed by one farmer using no-till and other standard management practices. EG were measured using close range photogrammetry techniques. In order to achieve a suitable characterization of the EG evolution over time and space, EGs were divided in three sections (bottom, middle and top) of equal length. Photographs were taken at least once in 2013, 2014 and 2018 (a total of five in I3 and three in B6). Cross section profiles along the EG perpendicular to the flow path direction were selected and their width, area and depth were determined from a graphical representation of the cross sections. EG volumes were estimated by the sum of interpolating sequential cross-section areas and multiplying by the distance between them.</p><p>Average EG erosion rates during 2013-2014 were 3.19 Mg ha<sup>-1</sup> year<sup>-1</sup> for B6 and 3.63 Mg ha<sup>-1</sup> year<sup>-1</sup> for I3. Values in agreement with rates estimated by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) of 0.49 to 5.18 Mg ha<sup>-1</sup> year<sup>-1 </sup>across the USA and other simulated values of 4.00 ± 1.76 Mg ha<sup>-1</sup> year<sup>-1</sup> for no till systems in the state of Iowa. The current study shows evidences that EG in no till systems may not stabilize after their formation. EG dimensions (depth, width and length, thus volume) varied over time and space during the continuously monitored period. In general, volumes tend to increase in the middle position while depths decrease in the bottom position. When the EG was filled, it reformed again in approximately the same location showing similar dimensions to that which existed prior to filling.</p>

Unmanned aerial vehicles can accurately, reliably, and economically compete with terrestrial mapping methods

2020 ◽  
Vol 8 (1) ◽  
pp. 57-74 ◽  
Author(s):  
Orrin Thomas ◽  
Christian Stallings ◽  
Benjamin Wilkinson
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Spatial Data ◽  
Mean Squared Error ◽  
Laser Scanner ◽  
Point Clouds ◽  
Unmanned Aerial Systems ◽  
Squared Error ◽  
Similar Accuracy ◽  
Aerial Systems

Structure from motion (SfM) and imagery-derived point clouds (IDPC) are excellent tools for collecting spatial data. However, reported accuracies from unmanned aerial systems (UAS) commonly fall short of their theoretical potential. The research presented here, using a DJI Inspire 2 with post-processed kinematic direct geopositioning, demonstrates that UAS mapping can be consistently accurate enough for use in place of, or in concert with, terrestrial methods (2 cm vertical root mean squared error). We further demonstrate that features that are missing or distorted in IDPC (e.g., roof edges, break lines, and above-ground utilities) can be collected from UAS-imagery stereo models with similar accuracy. Accuracy in the experiments was verified by comparison to data from a total station and terrestrial laser scanner (TLS). Use of the recommended hardware and stereo compilation reduced mapping costs by 40%–75% on three test projects.

LIGHTER-THAN-AIR (LTA) UNMANNED AERIAL SYSTEM (UAS) CARRIER CONCEPT FOR SURVAILLANCE AND DISASTER MANAGEMENT

2019 ◽  
Vol 3 ◽  
pp. 1255
Author(s):  
Ahmad Salahuddin Mohd Harithuddin ◽  
Mohd Fazri Sedan ◽  
Syaril Azrad Md Ali ◽  
Shattri Mansor ◽  
Hamid Reza Jifroudi ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Disaster Management ◽  
Unmanned Aerial Systems ◽  
Unmanned Aerial System ◽  
Border Control ◽  
Aerial Vehicles ◽  
Operational Safety ◽  
In Situ Methods ◽  
Aerial Systems

Unmanned aerial systems (UAS) has many advantages in the fields of SURVAILLANCE and disaster management compared to space-borne observation, manned missions and in situ methods. The reasons include cost effectiveness, operational safety, and mission efficiency. This has in turn underlined the importance of UAS technology and highlighted a growing need in a more robust and efficient unmanned aerial vehicles to serve specific needs in SURVAILLANCE and disaster management. This paper first gives an overview on the framework for SURVAILLANCE particularly in applications of border control and disaster management and lists several phases of SURVAILLANCE and service descriptions. Based on this overview and SURVAILLANCE phases descriptions, we show the areas and services in which UAS can have significant advantage over traditional methods.

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