Monitoring Environmental Change in the Tigris and Euphrates Basins
GRID-Europe and Sioux Falls, in collaboration with UNEP's Regional Office for West Asia, embarked on a joint study to monitor environmental change in the Tigris-Euphrates drainage basin. Remotely sensed imagery (Landsat MSS/ETM and Corona), as well as other ancillary data, were used to assess changes that have taken place in the region over the past 30 years (1970-2000).
The core of the basin is shared by four countries, Turkey, Syria, Iraq and Iran. In addition to large-scale ecosystem disruption, the Tigris-Euphrates river system has attracted growing international attention in recent years due to the high water stress facing this semi-arid region, which is becoming a growing source of geo-political tension between riparian countries.
The Tigris-Euphrates watershed has undergone extensive land-cover and land-use changes as a result of major hydraulic works and associated development schemes implemented when riparian countries entered the 'Age of Dams' in the late 1950s and which is continuing into the twenty-first century. The project focuses on two key environmental 'hotspots' that have undergone the greatest changes in the last decade; the headwaters of upper Mesopotamia and the marshlands of lower Mesopotamia at the confluence of the twin rivers. In the headwater region, hundreds of kilometres of species rich mountain valleys and terrestrial ecosystems have been inundated by a series of reservoirs created by a succession of large dams. Originally covering an estimated area of 15,000 - 20,000 km2, the Mesopotamian marshlands are one of the world's great wetlands whose aquatic ecosystem has supported unique human communities for millennia. Comprising the largest wetland ecosystem in Southwest Asia, their global significance stems from the role they play in the intercontinental migration of birds, and for sustaining rare and endemic flora and fauna, important jewels in the biodiversity crown. Located in the downstream section of the basin in southern Iraq and extending partly into Iran, the marshlands have been devastated by massive drainage schemes, the cumulative impact of upstream damming and war damages.
The results of this study, "The Mesopotamian Marshlands: Demise of an Ecosystem" were published in 2001 and were accompanied with an interactive IMS-based website (prototype), a suite of maps, and posters to help raise regional and global awareness about the scale and significance of environmental change in one of the world's leading water flashpoints. UNEP hopes that such scientific assessments will promote a better understanding of the challenges facing transboundary waters in the Middle East in the new millennium and encourage the international community to assist riparian countries in reaching an agreement on sharing the rivers' waters.
Iraq Marshlands Observation System
Since May 2003, remarkable and rapid environmental change has been taking place in the Iraqi Mesopotamian Marshlands. After over a decade of decline, in less than one year (May 2003 - March 2004), more than 20% of the original marshland area has been re-flooded.
During this critical phase, it is critical to monitor the distribution of the present reflooding and the nature of the associated ecological changes taking place. Systematic assessment of ongoing changes is essential to achieve a better understanding of the dynamics of the recovery process and to help support decision-makers and stakeholders undertake efficient rehabilitation measures.
The Iraq Marshlands Observation System (IMOS) is part of UNEP's “Support for
Environmental Management of the Iraqi Marshlands” project implemented by the
International Environmental Technology Centre (DTIE/IETC) and funded by the
Government of Japan through the UN Development Group Iraq Trust Fund. The IMOS
is designed and coordinated by UNEP's Post Conflict Branch and executed by GRID
Europe. This is
a decision-making support tool to assist key stakeholders to pragmatically
modify and adapt restoration plans in a timely manner, based on valid scientific
information. The main goals of the IMOS are to:
1. Develop and implement a monitoring system to systematically acquire, analyse and exchange information about changes in the Marshlands ecosystem;
2. Develop information products and services based on the data gathered to support management of the restoration process; and
3. Evaluate the success of wetland restoration and its impacts on the regional environment, including that of the northern Persian Gulf.
Remote sensing offers a unique method to monitor, assess and empirically quantify the changes taking place on a near real-time basis so as to advise restoration actions as rapidly as possible. The benefits of satellite remote sensing surveillance is not only in terms of its cost-effectiveness, global perspective and timeliness, but also given the prevailing security situation it offers an effective and in certain cases the only means to monitor and assess ongoing changes.
During a first phase of the IMOS project, a team of GRID-Europe's Earth Observation Section explored the data sources available and the potential methododologies to extract pertinent information from satellite imagery. One of the IMOS requirements being the provision of vegetation and inundation maps on a weekly basis, the team developed a novel approach based on object extraction and classification from MODIS imagery, using the eCognition software. The figure below shows the various steps followed to extract nine land cover classes at a resolution of 250 m.
Some outputs of the IMOS to be used in phase 2 of the project. NDVI was used to discriminate vegetation from non-vegetated surfaces
These preliminary results were encouraging, and this approach has been applied on an operational basis to derive and archive land cover maps of the marshes (2003-2004), as well as weekly maps for 2005.
GRID-Europe concluded the execution of the second phase of the Iraq Marshlands Observation System (IMOS), in which the monitoring work revealed a remarkable and steady recovery process underway.
Using MODIS Terra satellite imagery, synoptic maps (see figure below) were designed and produced, using a legend to illustrate the temporal distribution of marshland reflooding and wetland vegetation development, on a nominal weekly/biweekly basis since January 2005. In total, 92 map sets have been prepared for the three-year period from 2003-2005. In total, seven seasonal vegetation maps have been prepared for the Spring and Autumn, capturing the marshlands at their maximum and minimum extents respectively, on an annual basis for the period 2003-2005. All results have been placed in the public domain and made available on the IMOS website (http://imos.grid.unep.ch/), which is regularly updated to help ensure timely access for the Iraqi authorities, as well as partner organisation and interested stakeholders.
At the end of the second
phase of the project, three of the four
major objectives were fully met:
- Development and implementation of IMOS, consisting of an articulated ensemble of concepts, data, methodology, software and products, accessible through a website. Owing to the large size of the Iraqi marshlands and to the security situation, remote sensing was the only approach to observe their evolution. Daily MODIS imagery has been the main source of data, supplemented by a few IRS and Landsat images at a seasonal frequency. Thematic information was extracted from all the imagery by a unified, object-based approach followed by a fuzzy, multi-criteria classification. Because of the scarcity of field data, the role of the analyst's expertise was important in the process. The possibility to log and store the algorithms used assures full reproducibility of the results.
- Information products and services, of which the former consist of MODIS-based Simplified Land Cover and Inondation (SLCI) maps and statistics produced and included in weekly reports. Based on the higher-resolution imagery of IRS and Landsat, more detailed seasonal vegetation maps were also produced. All images, maps and reports are displayed in, and accessible from the IMOS website.
- IMOS is suitable to follow marshland progress in terms of vegetation and water surfaces’ evolution. The recovery is obvious. Since 2003, the total surface area of marshlands went from 15% to 40% of their maximal extent in the 1970s.
During the first half of 2006, the objectives of the third project phase were the following:
- Improvement of the methodologies used to derive marshlands water and vegetation maps based on MODIS, IRS and ASTER satellite sensors.
- Production of weekly MODIS-based simplified land cover and inundation maps, with accompanying statistics, in order to extend the time series starting in 2003. This includes validation of these maps using field data collected by UNEP’s Iraqi partners.
- Detailed mapping of the vegetation types and dynamics, using the high-resolution IRS and ASTER imagery.
- IMOS website maintenance.
- Conception and presentation of a ten-day training session on remote sensing and IMOS to three Iraqi professionals.
The training session took place in June 2006 and the trainees acquired expertise to operate the system in their country. To this end, methodologies, software licenses and computers were handed over to them. In spite of the expertise transferred during the training, and because of the overall situation in Iraq, it was acknowledged that IMOS would not be able to operate without outside help. After discussions amongst theProject's partners, PCoB agreed to fund some extra support from GRID during a transitory phase lasting until December, in order to facilitate a deep and durable rooting of the System in Iraqi institutions.
Drying of terrestrial vegetation and growth of hydrophytes in Al Qurnah between
03.02.06 (left) and 16.04.06 (right). IRS false colour composite.
For accessing the IMOS website, click here.