International Journal of Applied Earth Observation and Geoinformation 51 (2016) 37–46 Contents lists available at ScienceDirect International Journal of Applied Earth Observation and Geoinformation journal homepage: www.elsevier.com/locate/jag Use of MODIS satellite images for detailed lake morphometry: Application to basins with large water level fluctuations George Ovakoglou a , Thomas K. Alexandridis a,∗ , Thomas L. Crisman b , Charalampos Skoulikaris c , George S. Vergos d a Laboratory of Remote Sensing and GIS, Faculty of Agriculture, Aristotle University of Thessaloniki, Thessaloniki 54636, Greece b Department of Integrative Biology, University of South Florida, 4202 E. Fowler Ave. SCA 110, Tampa, FL 33620-8100, USA c Division of Hydraulics and Environmental Engineering, Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki 54636, Greece d Department of Geodesy and Surveying, Aristotle University of Thessaloniki, Thessaloniki 54636, Greece a r t i c l e i n f o Article history: Received 8 January 2016 Received in revised form 20 April 2016 Accepted 28 April 2016 Keywords: Remote sensing Digital depth model Bathymetry Lake bottom Lake bed Sedimentation a b s t r a c t Lake morphometry is essential for managing water resources and limnetic ecosystems. For reservoirs that receive high sediment loads, frequent morphometric mapping is necessary to define both the effective life of the reservoir and its water storage capacity for irrigation, power generation, flood control and domestic water supply. The current study presents a methodology for updating the digital depth model (DDM) of lakes and reservoirs with wide intra and interannual fluctuations of water levels using satellite remote sensing. A time series of Terra MODIS satellite images was used to map shorelines formed during the annual water level change cycle, and were validated with concurrent Landsat ETM+ satellite images. The shorelines were connected with in-situ observation of water levels and were treated as elevation contours to produce the DDM using spatial interpolation. The accuracy of the digitized shorelines is within the mapping accuracy of the satellite images, while the resulting DDM is validated using in-situ elevation measurements. Two versions of the DDM were produced to assess the influence of seasonal water fluctuation. Finally, the methodology was applied to Lake Kerkini (Greece) to produce an updated DDM, which was compared with the last available bathymetric survey (1991) and revealed changes in sediment distribution within the lake. © 2016 Elsevier B.V. All rights reserved. 1. Introduction The morphometry of a lake basin has a major impact on ecosystem structure and function through its influence on ther- mal regimes, mixing patterns, nutrient cycling and the extent of deep water anoxia (Wetzel, 2001). For reservoirs, however, the role of basin morphometry and its stability are of paramount impor- tance over the effective life of reservoirs and resulting water storage capacity for irrigation, power generation, flood control and domes- tic water supply. In contrast to the relatively slow rate of infilling of lake basins, reservoirs often experience rapid sedimentation reflecting both the extremely large watershed to lake area ratio and pronounced water level fluctuations and associated shoreline ∗ Corresponding author at: Laboratory of Remote Sensing and GIS, Faculty of Agriculture, Aristotle University of Thessaloniki, Univ. Box 259, Thessaloniki 54636, Greece. E-mail address: thalex@agro.auth.gr (T.K. Alexandridis). erosion multiple times annually to sustain engineered system func- tions (Thornton et al., 1996). Traditionally, lake bathymetric maps were developed from individual points along set transects where the position was trian- gulated by compass and water depth then measured with weighted ropes. Individual depth contours were subsequently constructed for the basin from multiple transects and related to average lake stage. In recent decades, most lake mapping has combined sonar depth finders and geographic positioning systems along multi- ple random transects across lakes using motorized boats (Kendra and Singleton, 1987; Moreno-Amich and Garcia-Berthou, 1989). Although the latter maps are accurate and less time consuming and can be used to chart distributions of macrophytes and fish, most lakes are still characterized by a single depth map, often decades or centuries old. Because of great potential for rapid infilling by upstream sediments, often producing internal deltas and overall differen- tial sedimentation patterns within the reservoir from shoreline erosion, bathymetric maps must be updated regularly to deter- mine trajectories in effective life of reservoirs for their intended http://dx.doi.org/10.1016/j.jag.2016.04.007 0303-2434/© 2016 Elsevier B.V. All rights reserved.