Building wetlands that recycle wastewater is one way of making up for declining levels of irrigation water
NAWABSHAH, Pakistan (AlertNet) - For farmer Asadullah Kerio, water shortages are a thing of the past. Since 2010, he has been irrigating his land with treated wastewater from a nearby ‘constructed wetland’ in Majeed Keerio village in Shaheed Benazirabad district, some 271 km (168 miles) northeast of Karachi.
“Use of treated wastewater has invigorated my farmland by increasing its fertility level, and I am saving the money I used to spend on applying costly fertilisers and other inputs for boosting soil fertility,” said the 30-year-old farmer.
Sugarcane, mango and banana are the major crops in this central district of southern Sindh province. The local climate is sultry and dry, with summer temperatures soaring up to 49 degrees Celsius.
But the area under cultivation has shrunk significantly as many farmers have been deprived of irrigation water due to a drop in the Indus River flows that feed the district’s canals.
The president of the Sindh Growers Board, Abdul Majeed Nizamani, said annual production of mango, sugarcane, wheat and vegetables has declined by almost 40 percent compared with six or seven years ago because of worsening water shortages.
“The grim situation has rendered many farmers unemployed, most of whom have moved to nearby urban centres in search of livelihoods,” he said.
Majeed Kerio village, which has a population of around 6,000 and is situated within the bustling town of Nawabshah, had been grappling with stinking wastewater that overflowed and stagnated in the streets due to a dysfunctional drainage network. The grey polluted water was also eroding the fertility of local farmland.
But since April 2010, its troubles have been turned around by a constructed wetland project, the first in Pakistan.
NATURAL ECOSYSTEM MODEL
Constructed Wetland (CW) is a low-cost, biological wastewater treatment technology designed to mimic processes found in natural wetland ecosystems, according to the United Nations Human Settlements Programme (UN-Habitat), which has provided technological support for the project.
The shallow basin of the wetland is filled with a filter material, usually sand or gravel, and planted with vegetation tolerant of saturated conditions. Domestic wastewater accumulates in a pond that feeds it into the basin through an inlet-outlet system.
It then flows over the surface or through the substrate, and is discharged from the basin through the system controlling the amount of wastewater in the wetland. The treated water can be used for most purposes except drinking and cooking.
The Rs8.359 million ($88,455) cost of the Majeed Kerio wetland was shared by the World Wide Fund for Nature-Pakistan and community members, paying Rs2.932 million and Rs5.426 million respectively.
It is an investment that is bringing substantial benefits for local people, as well as farmers.
“The beauty of our village has been restored, as now there is no fetid water in the streets. There has also been a substantial fall in water-borne and skin diseases such as malaria, cholera and typhoid,” said community health worker Jameela Fatima.
AGRICULTURE AT RISK
According to a study by the Global Change Impact Studies Centre in Islamabad, Pakistan’s agriculture output could fall by nearly 30 percent by 2030 due to a 6 percent decline in rainfall over that period, caused by climate change.
In 2010 and 2011, Pakistan suffered heavy flooding due to intense monsoon rains. But this year, southern parts of the country are experiencing drought conditions – suggesting that weather patterns are becoming more unpredictable.
Jawaid Ali Khan, director-general of Pakistan’s ministry of climate change, said the agricultural sector has been losing growth momentum due to flooding, depleting underground water resources, decreasing water flows in the Indus River and increased pest attacks due to rising temperatures.
He added that the agriculture sector is at risk from the shrinking availability of irrigation water, which was around 20 percent below average in the fiscal year 2011-2012, which ended on July 31.
According to Pakistan’s 2011 Economic Survey, agricultural growth has slowed to 2.7 percent in the last decade compared with 4.4 percent in the 1990s and 5.4 percent in the 1980s.
“Pakistan is among the 17 countries of the world that may face severe water shortages by 2025. Therefore the reuse of wastewater after proper treatment for agriculture will be the future alternative, viable option,” said Ibrahim Mughal, president of the Pakistan Agri Forum.
SAVING AND REUSING WATER
Kamran Naeem, a water and sanitation project manager at UN-Habitat Pakistan, said the South Asian nation must use water more efficiently and deploy more of the latest water-saving technologies, including constructed wetland.
The vice chancellor of Islamabad’s Quaid-i-Azam University, Masoom Yasinzai, noted that access to safe drinking water in Pakistan has dropped drastically over the past 60 years and could fall to less than 1,000 cubic metres per capita by the end of this year. That compares with more than 5,000 cubic metres per person in the early 1950s.
“The promotion of small-scale sewage treatment and wastewater reuse systems in other parts of Pakistan, like constructed wetlands, can be of great help in tackling the depressing water scenario that is emerging,” he said.
He urged the Pakistani government to follow a policy of reusing treated wastewater for agriculture.
Pakistan now has five constructed wetlands - two in Nawabshah town, and three in neighbouring Sanghar district in central Sindh province.
“Although the cost of building up such wetlands may increase if they are developed for the town or city level, the environmental and health benefits are enormous,” said Muhammad Azeem, an urban planning expert at the ministry of climate change.
Saleem Shaikh and Sughra Tunio are development reporters based in Karachi, Pakistan.
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