UAV Photogrammetry for Elevation Monitoring of Intertidal Mudflats

Dai, Weiqi; Li, Huan; Zhou, Zeng; Cybele, Stephanie; Lu, Chengpeng; Zhao, Kun; Zhang, Xiaoyan; Yang, Huatao; Li, Dingyuan

doi:10.2112/si85-048.1

Cited by 9 publications

(5 citation statements)

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“…They conducted a very similar survey in an area of~10 ha flying at 100 m and with a GCP density of 1.5 GCP/ha and were able to reach an error ranging between 3.9 and 2.7 cm. In other studies where the UAVs flew at higher altitudes, between 80 to 180 m, and the GCP density was very low (below 0.2 GCP/ha), the error increased to 10-20 cm till 5 m [111][112][113]. The relation between GCP density and RMSE from the previously cited researches is shown in Figure 11.…”

Section: Comparisons With Other Studies With Uav In Wetlandsmentioning

confidence: 76%

“…The distribution of the GCPs for Brunier et al (2020) [110] and Jaud et al (2016) [107] was homogeneous and the distance between each GCP was mostly coherent, which probably resulted in achieving a low RMSE (i.e., 3-4 cm). In studies with greatly extended areas, the GCP distribution was neither dense [112] nor homogeneous [111,113], causing higher RMSE (i.e., >10 cm). The best GCP distribution seems to be around~2.5 and 3 GCP/ha, which is 2-3 GCP every 100 m homogeneously and equally spaced around the tidal flat.…”

Section: Comparisons With Other Studies With Uav In Wetlandsmentioning

confidence: 95%

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Evaluating Short-Term Tidal Flat Evolution Through UAV Surveys: A Case Study in the Po Delta (Italy)

2021

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The use of Unmanned Aerial Vehicles (UAV) on wetlands is becoming a common survey technique that is extremely useful for understanding tidal flats and salt marshes. However, its implementation is not straightforward because of the complexity of the environment and fieldwork conditions. This paper presents the morphological evolution of the Po della Pila tidal flat in the municipality of Porto Tolle (Italy) and discusses the reliability of UAV-derived Digital Surface Models (DSMs) for such environments. Four UAV surveys were performed between October 2018 and February 2020 on an 8 ha young tidal flat that was generated, amongst others, as a consequence of the massive sediment injection into the Po Delta system due to the floods of the 1950s and 1960s. The DSM accuracy was tested by processing (i.e., photogrammetry) diverse sets of pictures taken at different altitudes during the same survey day. The DSMs and the orthophotos show that the tidal flat is characterised by several crevasse splays and that the sediment provision depends strictly on the river. During the study period, the sediment budget was positive (gaining 800 m3/year and an average rate of vertical changes of 1.3 cm/year). Comparisons of DSMs demonstrated that neither lower flight altitudes (i.e., 20–100 m) nor the combination of more photos from different flights during the same surveys necessarily reduce the error in such environments. However, centimetric errors (i.e., RMSEs) are achievable flying at 80–100 m, as the increase of GCP (Ground Control Point) density is the most effective solution for enhancing the resolution. Guidelines are suggested for implementing high-quality UAV surveys in wetlands.

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Section: Comparisons With Other Studies With Uav In Wetlandsmentioning

confidence: 76%

Section: Comparisons With Other Studies With Uav In Wetlandsmentioning

confidence: 95%

Evaluating Short-Term Tidal Flat Evolution Through UAV Surveys: A Case Study in the Po Delta (Italy)

2021

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“…A high‐resolution digital elevation model (DEM) of the creek intertidal zone was obtained from UAV photogrammetry during the lowest tide with accuracy of < 10 cm per pixel (Dai et al 2018). The DEM was combined with water depths to estimate the intertidal flooded area and water volume upstream of the time‐series station every 5 min.…”

Section: Methodsmentioning

confidence: 99%

Alkalinity export to the ocean is a major carbon sequestration mechanism in a macrotidal saltmarsh

Yau

Xin

Chen

et al. 2022

Limnology & Oceanography

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Saltmarshes are a blue carbon ecosystem accumulating large quantities of organic carbon in sediments. Some of this carbon can be transformed into dissolved inorganic carbon (DIC) and methane (CH 4 ) that may eventually be exported to the ocean or atmosphere. Although extensive studies have quantified specific components of the carbon budget such as carbon burial, limited attention has been given to pore-water-derived carbon and total alkalinity (TA) exports to the ocean. Here, we quantified lateral exports to the ocean (outwelling) of 202 AE 160 and 78 AE 75 mmol m À2 d À1 of DIC and TA, respectively. The TA : DIC concentration ratio in the creek waters was $ 1, implying TA production from anaerobic mineralization in sediments. The lateral TA exports were comparable to the local (94 AE 48 mmol m À2 d À1 ) and national ($ 50 mmol m À2 d À1 ) organic carbon burial. High TA exports could locally increase the ocean buffering capacity and contribute bicarbonate to the coastal ocean, acting as a long-term carbon storage. Pore water traced by radon contributed 28-37% and 58-69% of DIC and TA exports. Separating the two major DIC components (i.e., CO 2 emissions and alkalinity exports) is essential to resolve the carbon sequestration potential from saltmarshes. Here, dissolved CO 2 emissions to the atmosphere accounted for 3-5% of total DIC outwelling. CH 4 emissions played a minor role offsetting around 0.3 to 6% of the carbon sequestration. Overall, we demonstrate that alkalinity export into the ocean can be an overlooked carbon sequestration pathway in saltmarshes at rates comparable to carbon burial.

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“…Despite the combination of a greatest number of coastal no-fly zones (due to controlled aerospace from the military, proximity to aerodromes or natural protected areas) with crowded beaches can discourage UAV citizen science coastal applications in EASA countries, our protocol can also be applied to other environments or scientific disciplines where accurate cost-effective topographic monitoring is needed. In fact, multi-temporal UAV-SfM has already been used by professional researchers around the world for monitoring erosion in mudflats 72 , badlands 73 , agricultural watersheds 74 , rivers 75 and open-pit mines 76 . Additionally, UAV-SfM topographic data has also been used for non-erosion purposes to monitor both natural processes, such as landslide dynamics 77 , sediment retention dams filling 78 , crops growth variability 79 , forest trees growth 80 , snow depth 81 and glaciers melting dynamics 82 , or anthropogenic processes, such as landfills growth rates 83 , environmental contamination 84 or hiking trails conditions 85 .…”

Section: Discussionmentioning

confidence: 99%

Citizen science for monitoring seasonal-scale beach erosion and behaviour with aerial drones

Pucino

Kennedy

Carvalho

et al. 2021

Sci Rep

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Sandy beaches are highly dynamic systems which provide natural protection from the impact of waves to coastal communities. With coastal erosion hazards predicted to increase globally, data to inform decision making on erosion mitigation and adaptation strategies is becoming critical. However, multi-temporal topographic data over wide geographical areas is expensive and time consuming and often requires highly trained professionals. In this study we demonstrate a novel approach combining citizen science with low-cost unmanned aerial vehicles that reliably produces survey-grade morphological data able to model sediment dynamics from event to annual scales. The high-energy wave-dominated coast of south-eastern Australia, in Victoria, is used as a field laboratory to test the reliability of our protocol and develop a set of indices to study multi-scale erosional dynamics. We found that citizen scientists provide unbiased data as accurate as professional researchers. We then observed that open-ocean beaches mobilise three times as much sediment as embayed beaches and distinguished between slowed and accelerated erosional modes. The data was also able to assess the efficiency of sand nourishment for shore protection. Our citizen science protocol provides high quality monitoring capabilities, which although subject to important legislative preconditions, it is applicable in other parts of the world and transferable to other landscape systems where the understanding of sediment dynamics is critical for management of natural or anthropogenic processes.

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UAV Photogrammetry for Elevation Monitoring of Intertidal Mudflats

Cited by 9 publications

References 0 publications

Evaluating Short-Term Tidal Flat Evolution Through UAV Surveys: A Case Study in the Po Delta (Italy)

Evaluating Short-Term Tidal Flat Evolution Through UAV Surveys: A Case Study in the Po Delta (Italy)

Alkalinity export to the ocean is a major carbon sequestration mechanism in a macrotidal saltmarsh

Citizen science for monitoring seasonal-scale beach erosion and behaviour with aerial drones

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