The Mesopotamian Marshes: A Case Study of an Ecology in Peril

Current Events Oct 19, 2022

The Mesopotamian Marshes span roughly 10,000 square kilometres of alluvial salt marshes, swamps and freshwater lakes along Iraq’s southeastern border with Iran. A major floodplain of the Tigris and Euphrates Rivers, the Marshes were nearly wiped out in the 1990s by forced draining policy under President Saddam Hussein. While flooding efforts after his 2003 overthrow have reclaimed some of the Marshes’ previous land (Fig. 1), novel threats posed by upstream damming, salinization and climate change have cast doubt on the Marshes’ future anew. This paper is an exposition of the ecological circumstances, effects and future of modern anthropogenic influence on the Mesopotamian Marshes, a fascinating ecology in peril.

Until the 1990s, the formerly-20,000 square-kilometre Mesopotamian Marshes was the largest wetland system in the Middle East. The area encompasses the Central, Hammar, and Hawizeh Marshes across an ecosystem of exceptional natural significance. Host to a wide array of aquatic biota, the Marshes also remain a wintering area for various endangered East Asian migratory birds and the sole breeding area for some local species, such as the Iraq babbler (Turdoides altirostris) and the endangered Basra reed-warbler (Acrocephalus griseldis). As part of the crucial nitrogen cycle, local diazotrophic phytoplankton help plants such as reeds and rushes ingest fixed nitrogen for growth. For nearly 200,000 local “Marsh Arabs,” the sustenance of ecosystem services is crucial for their economic trades, namely breeding reed-eating water buffalo, fishing and rice cultivation. Nevertheless, Iraq has enacted no legal protections for the Marshes’ biodiversity, leaving species prey to the ecological harms described in this paper.

Merging east of the Central Marshes at al-Qurnah, Iraq, the Tigris and Euphrates are the Marshes’ very ecological lifeblood. As late as the 1960s, the rivers supplied the lion’s share of their annual water during the spring flood pulse from March to May. Subsequently, however, when Turkey, Syria and Iraq began conducting major hydrological projects to harness the rivers’ flows for energy and irrigation, the flood pulses have gradually diminished in importance for seasonal inflow. As a result of the proliferation of hydrological infrastructure upstream, the Euphrates’s mean annual flow since 1971 has been nearly halved from 638 to 330 m3 per second as measured at Hindiyah, Iraq (Fig 2.).

With the mounting effects of upstream damming on river flow, the early 1990s proved a grim dawn to further threats. Having been long identified as a hotbed of anti-regime Shia Islamic support, the Iraqi government began draining the marshes as punishment to the locals. By the time the drainage program was halted after the 2003 invasion, 90% of the Mesopotamian Marshes had been drained and left to desiccate. This reduction dealt a massive blow to ecological carrying capacity, causing mass wildlife extirpation which the ecological system could no longer sustain, not to mention the internal displacement of 250,000 Marsh Arabs. At least 60 bird species who exclusively bred in the marshes were designated “at risk”. A subsequent UNEP-implemented rehydration project reported surface water and vegetation restoration to 58% of the original marshland by 2006 (Fig. 1) (to the extent that standing water was seasonal and vegetation was dense to some degree), though progress stagnated in 2007-08 due to unprecedented drought. Further reflooding efforts have hardly eclipsed the original 2005 gains.

With a crippling 2018 drought that cut water levels by over three feet, and most recently the 2020-21 rain season which was the second driest in four decades, the marshes’ salinity levels are at a crisis point. As a more realistic and sobering projection, the Conflict and Environment Observatory roughly estimates a regular summer high of 56° in the nearby major Iraqi port of Basra by the 2060s, up from a record-shattering 53° in 2021; though 56° itself nears the very limits of human survivability in extreme heat.

To the extent that the Euphrates’s flow has historically been dictated by the level of watershed precipitation, a weak observed correlation between changes in rainfall and changes in river flow after 1971 belie a firm anthropogenic influence. Since then, the percentage of total rainfall in the river’s upstream basin that flows into Iraq has plummeted from 41% to 7%. An emerging primary culprit is easy to spot: both the Tigris and the Euphrates originate in eastern Turkey, flowing swiftly into Syria and Iraq thereafter. While Iraq and Syria’s water dependency ratios both exceed 50% (over half of both countries’ groundwater and transboundary surface water flows come from other countries), Turkey’s is just 1%.

As part of the Güneydoğu Anadolu Projesi (GAP) project, the country is at work on over 40 hydroelectric projects for irrigation and energy along the Tigris and Euphrates with few signs of abating. Anxious about developing its largely Kurdish and historically anti-regime southeast, the firm Turkish position on energy incentives has helped prevent the ratification of any trilateral agreement with Syria and Iraq concerning riparian flows. As of 2021 the GAP has an unclear completion date, and prospects indicate an aggravation of the ecological issues stemming from upstreaming damming, as well as greater diplomatic grievances against Turkey from water-deprived Syria and Iraq.

Now aggravated by increased Turkish damming upstream, the expected reversal of static progress on reflooding the marshes since 2003 will likely be aggravated by the marshes’ accelerated salinization. The Iraqi government’s use of embankments during the 1990s draining separated the marshes from each other, making for mass desiccation and desertification of 70% of the drained area . Subsequent reflooding was in many cases unable to balance the areas’ salinity owing to the wrongful use of saline water. With the onset of mass upstream damming, the increase in marsh salinity has been contemporary with the reduction in water flow and the loss of spring flood pulses since the early 1970s. Higher soil salinity poses a threat to the Marsh Arabs’ rice cultivation, with levels exceeding than 8 ds/M (deciSiemens per metre) making rice and wheat ungrowable; only the Hawizeh Marshes permit cultivation past the normally less-saline outskirts. While increased salinity may have differential effects for aquatic species depending on their saltwater tolerance, the Marshes risk a major long-term decline in biodiversity with, for example, the decline of the freshwater-based mangar fish. In addition to natural habitat decline of species indigenous to the Marshes, more salt-resistant species of crabs and shrimp will see a habitat range expansion in saline/brackish water conditions. In turn, this habitat expansion may affect the diet and fishing trade of the Marsh Arabs, who have historically supplied a major share of the fish Iraqi markets. As greater upstream damming and average temperatures threaten to undo the work of reflooding the Marshes, salinization will likely exercise greater influence over habitats and general biodiversity therein.

Pressing as they are, the immediate ecological threats of upstream damming and salinization may eventually be shadowed by a longer-term threat that will have a more decisive effect soon enough: climate change. The importance of the Mesopotamian Marshes in a mostly-arid region cannot be overstated, and Iraq’s own dependency ratio on cross-border river flows to supplement it sets it up for future disasters. The US Nat Ocean and Atmospheric Administration has already attributed half of the Eastern Mediterranean trend of drying bodies of water throughout the 20th century to forced climate change. Increasing regional temperatures have been identified as a threat to snowmelt in the eastern Turkish mountains from where the twin rivers abound. Supplying 60%-70% of total runoff into the Euphrates each year, the long-term drying up of this precipitation could eventually stem the river’s flow by anywhere between 29% and 73% by 2099. The 2007-09 drought period throughout the Fertile Crescent already halted steady progress on marsh reflooding with a 60%-80% drop below normal precipitation rates. In the interim, regions with a high dependency ratio on cross-border water flow, such as Iraq, will see the acute effects of climate change well before that date. For an area like the Mesopotamian Marshes, which is situated near the end of the Tigris-Euphrates flow path before they merge and empty into the Persian Gulf, inaction on current ecological issues spells impending disaster.

Examining the mounting effects of upstream river damming, salinization and climate change on the Mesopotamian Marshes’ ecology, this paper presents a grim prognosis for the area’s future. Over time, the drop in annual water flow from the Tigris and Euphrates rivers coupled with increased salinization and evaporation of vital precipitation for river flow will put greater strain on local wildlife to find food and maintain their natural habitats, not to mention the local Marsh Arabs who struggle daily to secure these. Ecological carrying capacity diminishes year by year as these threats contract the chain of nutrient-based and habitat needs; fewer and fewer organisms may be sustained. The severity of these issues demands swift action to mitigate their effects lest the Mesopotamian Marshes disappear forever, and much sooner than casual observers may perceive.

Figure 1: Comparison of NASA satellite images showing the Marshes area in February 2000 vs. post-reflooding in February 2006 (NASA Earth Observatory, 2002).

Figure 2: Declining mean annual flow of the Euphrates river as recorded at Hindiyah, Iraq (al-Quraishi and Kaplan, 2021).

Cover photo by Paul Dober. Wikimedia Creative Commons.

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