Challenges of defining the floodplain through the “mean ordinary flood line” approach using remote sensing in Brazil: a case study of the São Francisco River

Abstract

The “Mean Ordinary Flood Line” (MOFL) is a conceptual line adopted by Brazil’s Federal Government to delineate land within the floodplain under its ownership and jurisdiction having major social implications. Past attempts at the cartography of this line have encountered strong difficulties brought either by a low precision or an excessive cost. In this article, we propose a method based on historical water gauge data to determine the water level corresponding to the MOFL. Satellite images coincident with past dates when the MOFL was reached are selected and processed to extract the water surface from which the MOFL can then be produced. The approach was implemented in a 600 km reach of the São Francisco River in Minas Gerais as a pilot project. A field survey served to validate the results. The positional accuracy of the MOFL was estimated at 24 m which was considered excellent since mostly Landsat images with a spatial resolution of 30 m were used.

Estimating Flooding at River Spree Floodplain Using HEC-RAS Simulation

“…Floodplains are formed as the rivers erode their own banks. As the river flows, it washes material downstream of the bank, and when a flood occurs, this material or sediment largely composed of a layer of silt, sand, and mud, is suspended in water, and added to the floodplain [14][15][16][17]. Floodplains constitutes a valuable part of the environment as they filter, store, and release floodwaters, recharge aquifers, store a variety of sediments, and also provide a habitat for a diversity of wildlife [18][19][20][21][22].…”