The estimation of marshland degradation in southern Iraq using multitemporal Landsat TM images

Abstract

Characterization of the marshlands of southern Iraq using Landsat TM data enabled an estimation of the rate at which disruption of water supply has led to the collapse of the ecosystem. Image classification techniques were used to estimate vegetation distribution using an NDVI image, and the areal coverage of water, using bands 1 to 5 of the TM. The Al Amarah marsh to the north of the Euphrates River has seen a reduction of 90 per cent in its areal extent between 1992 and 1994. South of the Euphrates river the Hawr al Hammar marsh has undergone a similar reduction in areal extent between 1992 and 1994, but the collapse of vegetation occurred predominantly between 1993 and 1994. Vegetation collapse appears to be linked to the completion of drainage projects that prevent the influx of nutrient rich spring flood waters to the marshes. East of the Tigris river, the Hawr al Hawizah marsh was observed to have undergone a decline of 40 per cent in the amount of vegetation present between 1992 and 1994. Inundation northwest of a series of barrages around the northern perimeter of the Hawr al Hawizah marsh in 1993 and 1994 suggests that disruption of the influx of water from the Nahr al Musharrah river is the cause of vegetation decline.