By: FARAZ AHMED CHANDIO
The Indus Delta, recognized as a Ramsar wetland, is the fifth largest delta in the world and one of the most vulnerable coastal ecosystems. It extends from Sir Creek in the east to Phitti Creek in the west, with its apex at Banoo town in district Sujawal, Sindh. This fan-shaped delta supports the seventh largest mangrove system globally and is characterized by extensive tidal mudflats. Over time, however, the delta has undergone severe environmental degradation due to reduced river flows, sediment shortages, seawater intrusion, climate change, land subsidence, and human activities.
Historically, the active Indus Delta covered around 1.30 million hectares in 1833 and featured seventeen active creeks. Today, only two creeks, Khobar and Khar, remain functional, and the active delta area has shrunk to about 0.1 million hectares, reflecting a 92 percent reduction. The loss of freshwater flow and sediment supply has been a major driver of this contraction, weakening the natural processes that once sustained the delta’s growth and stability.
Vegetation patterns in the delta have fluctuated over the past decades. Satellite data show that vegetation expanded gradually from 1990 to 2010 but declined afterward. Mangrove forests covered more than 103,000 hectares in 1990, decreased significantly by 2005, and later increased again by 2017, largely due to plantation programs. Despite these efforts, dense mangroves cover only a small portion of tidal floodplains, while large areas remain barren or submerged.
Climate indicators reveal noticeable warming trends. Land surface temperatures have risen by about 1.74°C over nearly three decades. Summers have become hotter, winters slightly colder, and rainfall patterns have shifted, with decreases during monsoon months but increases in late monsoon periods. River discharge below Kotri Barrage has declined dramatically, reducing freshwater supply and intensifying seawater intrusion.
Soil conditions across the delta indicate widespread salinity and sodicity, with nearly half of soils classified as saline-sodic. Surface water bodies are largely saline and unsuitable for drinking or irrigation, while groundwater shows high chloride levels and, in some areas, arsenic contamination. Subsurface seawater intrusion is estimated to affect more than 88 percent of the delta’s area.
Coastal erosion has significantly altered the shoreline, particularly on the left bank of the Indus River, where mangrove density is lower and land slopes are flatter. The shoreline has shifted inland by hundreds of meters, and tens of thousands of hectares of land have been degraded or submerged due to seawater intrusion.
The environmental decline has had serious socioeconomic consequences. Most residents rely on agriculture, fishing, or daily labor, yet a large majority live below the poverty line. Poor water quality and environmental stress have contributed to widespread health issues, including gastrointestinal diseases, skin problems, and chronic illnesses. Local communities also report rising temperatures, declining rainfall, and stronger winds over recent decades.
The delta’s vulnerability to extreme events is high. A storm surge or tsunami raising sea levels by about five meters could inundate more than two-thirds of the region, threatening both ecosystems and human settlements.
To address these challenges, several strategies have been proposed. Increasing freshwater flows below Kotri Barrage would help reduce seawater intrusion and restore ecological balance. Restoring old river channels could distribute freshwater and sediments more effectively across the delta. Expanding mangrove plantations would strengthen natural coastal defenses, enhance biodiversity, and support fisheries. Promoting biosaline agriculture with salt-tolerant crops could make degraded land productive again, while freshwater lake restoration would improve drinking water availability and groundwater recharge. Sustainable livelihood initiatives such as aquaculture, ecotourism, and improved infrastructure could uplift local communities, and stronger environmental regulations would help protect remaining natural resources.
Overall, the Indus Delta remains an ecologically vital but highly threatened landscape. Scientific evidence highlights the urgency of coordinated management, restoration, and climate adaptation efforts to safeguard its biodiversity and support the millions of people who depend on its resources.
