Applications of Unmanned Aerial Systems (UASs) in Hydrology: A Review

Abstract

In less than two decades, UASs (unmanned aerial systems) have revolutionized the field of hydrology, bridging the gap between traditional satellite observations and ground-based measurements and allowing the limitations of manned aircraft to be overcome. With unparalleled spatial and temporal resolutions and product-tailoring possibilities, UAS are contributing to the acquisition of large volumes of data on water bodies, submerged parameters and their interactions in different hydrological contexts and in inaccessible or hazardous locations. This paper provides a comprehensive review of 122 works on the applications of UASs in surface water and groundwater research with a purpose-oriented approach. Concretely, the review addresses: (i) the current applications of UAS in surface and groundwater studies, (ii) the type of platforms and sensors mainly used in these tasks, (iii) types of products generated from UAS-borne data, (iv) the associated advantages and limitations, and (v) knowledge gaps and future prospects of UASs application in hydrology. The first aim of this review is to serve as a reference or introductory document for all researchers and water managers who are interested in embracing this novel technology. The second aim is to unify in a single document all the possibilities, potential approaches and results obtained by different authors through the implementation of UASs.

Remote Sensing of Wetlands in the Prairie Pothole Region of North America

“…However, SfM lacks point cloud density compared to lidar and is, therefore, best utilised in combination with lidar where available [97]. Combined lidar and SfM methods can be applied to a variety of wetland studies for applications such as vegetation inventories, identifying open water extents, flood detection analysis, and topographical features [98,99]. UAV imagery has been assessed for wetland classification using pixeland object-based analyses, corroborating that object-based analysis typically yields greater accuracies.…”

A Review of Unoccupied Aerial Vehicle Use in Wetland Applications: Emerging Opportunities in Approach, Technology, and Data

“…A potential solution to this tradeoff is combining LiDAR data with SfM data [61]. Combined LiDAR and SfM methods can be used not only in vegetation inventory studies, as demonstrated in this review, but also in surface water, flooding detection analysis [38], and morphological features [35].…”

“…Other researchers have explored similar topics involving the use of UAVs in aquatic ecology, wetland identification, and hydrologic modeling [2,30,37]. Vélez-Nicolás et al [38] conducted a literature review on UAV applications in hydrology and selected 122 research papers for analysis, while Jeziorska [37] explored UAV sensors and cameras for a broad array of applications, and coupled this with a focus on 20 highlighted research papers pertaining to wetland and hydrological modeling. Mahdianpari et al [30] examined wetland classification studies from 1980-2019 across North America using a variety of remote sensing techniques, and found only four UAV-based studies, all of which took place in Florida.…”

Assessing the Impacts of Rising Sea Level on Coastal Morpho-Dynamics with Automated High-Frequency Shoreline Mapping Using Multi-Sensor Optical Satellites

“…However, video-imaging techniques also have limited spatial coverage since they are fixed, site-specific ground-based technologies [30]. While airborne methods and UAVs are more flexible in their potential coverage, they are also limited due to dependence on human operators, which discourages continuous observation [33], whereas understanding coastal dynamics requires continuous and fre-quent monitoring of shorelines. Consequently, long-term, uninterrupted, and updated information of shoreline displacement that is vital for coastal engineering and sustainable adaptation plans is usually scarce in many coastal areas [34].…”