Remote Sensing Monitoring of the Bottom Topography in a Shallow Reservoir and the Spatiotemporal Changes of Submerged Aquatic Vegetation Under Water Depth Fluctuations

Abstract

Monitoring the growth and distribution of submerged aquatic vegetation (SAV) is crucial to the protection and restoration of the ecosystem of inland reservoirs. Considering the high sensitivity of SAV to water depth fluctuations in Guanting Reservoir, China, in this study, we realized the reconstruction of bottom topography by combining changing water level with a long time series remote sensing technology and explored the spatiotemporal succession law of SAV by analyzing the effect of water depth on the spatiotemporal distribution of SAV. Results of water depth spatial distribution in Guanting Reservoir were obtained by using water and land boundary lines to construct underwater terrain contours. The accuracy of estimated water depth data from remote sensing images was verified with measured water depth data, and the average relative error of water depth estimation results was about 0.25 m. The experimental results show that (1) the SWIR bands of Landsat images could avoid the interference of aquatic vegetation and realize the separation of land and water; and (2) after separating water area from land, an SWIR1_NIR index was used to effectively map SAV distribution in the reservoir. The results also indicate that the distribution of SAV in the reservoir is suitable for the water depth range of 0 − 2 m. Water depth fluctuations cause changes in the spatial distribution of suitable water depth. It is the main reason for the change of SAV distribution area in the reservoir during the past 20 years.

A Bibliometric Analysis of Lake Restoration with Submerged Macrophytes

“…For example, Ghirardi et al (2022) [161] and Xia et al (2022) [162] explored the decade scale of SAV dynamics using remote sensing images, providing a reference area for restoration. The classification accuracy of SAV changed from 60% to nearly 95% in existing studies [158,[163][164][165], which were mainly limited by the resolution of images, water depth, water color, and spectral traits of specific submerged macrophytes [158,166]. With the increase in the resolution of satellite images, the dynamics of specific aquatic macrophyte species can also be interpreted.…”

Observation of the Coastal Areas, Estuaries and Deltas from Space

“…LiDAR systems provide the most accurate measurements of surface elevation and can be used to map vertical structure of marsh vegetation and mangrove forests. The potential for green light to penetrate low turbidity water can provide bathymetry (e.g., Gong et al 2021) to approximately 10 m in very clear water cases (e.g., Thomas et al 2021). These same green LiDAR measurements can be used to map the structure of SAV that are known to be present.…”

Automatic Classification of Submerged Macrophytes at Lake Constance Using Laser Bathymetry Point Clouds

“…Airborne laser bathymetry (ALB) is a laser scanning technique used to measure water body bottom topography [19][20][21][22] or to detect the presence of underwater objects [23]. LiDAR has been used occasionally for mapping submerged vegetation, focusing mainly on distinguishing between the presence and absence of vegetation [15,[24][25][26][27].…”