The recently started Multiscale Observation Networks for Optical monitoring of Coastal waters, Lakes and Estuaries (MONOCLE) project aims at an improved characterisation of water-leaving reflectance and water quality over inland and transitional waters, such as river deltas and estuaries, at multiple spatial scales. The combination of satellite and drone imagery with additional in-situ observations will enable improved Total Suspended Matter (TSM) and chlorophyll-a retrievals at maximised spatio-temporal resolution. These improved retrievals will be beneficial to various end-user groups, such as the water modelling community. An example of river sediment transport is given in the 100 m image of 1 April 2017, which shows the Danube river flowing into the Black Sea in northeast Romania, one of MONOCLE's study areas. The light-blue whirls just off-shore indicate substantial amounts of sediments from the Danube outflow. The green-brown area is the Danube Delta Biosphere Reserve, a 6,300 km2 area with numerous lakes, ponds, small islands, and wetlands. The area gives home to more than 300 bird and about 90 fish species. MONOCLE has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776480. Discover more about the project, its goals and partners at 'Monitoring water quality in your backyard'.