# **Box  2.4  Wastewater use in a low-income country: Kumasi, Ghana**

In Kumasi, Ghana, with a population of about 1.1 million in 2000, and a population growth rate of 6 percent, 80–90 percent of the perishable vegetables consumed in the city are produced on a few sites in the city itself. Farmers take advantage of fertile soils along streams and drains passing the city to grow popular exotic vegetables such as spring onions, lettuce and, cabbage which require frequent watering. Although exotic crops are not part of the traditional diet, they are in high demand in the booming street food sector where the common ‘rice and chicken’ dish now comes with a raw salad. Since wastewater collection and treatment only covers 4 percent of the city, all streams are heavily polluted with stormwater, grey water, and excreta, resulting in fecal coliform levels on the vegetables of 10<sup>6-7</sup> at farm gate. As security of land tenure is low, farmers hardly ever invest in irrigation infrastructure except for mobile equipment such as watering cans, small 2-4 KW pumps, or dugouts near or in smaller streams.

Like in most parts of West Africa, the typical urban vegetable farmer is a male 30–40 years old, and very often a migrant from the another region. The land he is farming is likely government-owned, and may be considered unfit for construction. Individual plots are only 0.05-0.1 hectares large but labor-intensive. Lettuce cultivation is especially labour-intensive, requiring twice-daily watering which consumes up to 60 percent of the labor input. Although Kumasi lies in the humid tropics with annual rainfall of 1400 millimeters, crops must be watered every day that it does not rain. The highest profits are obtained in the two short dry (lean) seasons. Over the year, farmers specialized in exotic vegetables might harvest up to 10 lettuce crops, 2–3 cabbage, and 8–9 times spring onions and can earn about US$400-800 which is at least twice as much as their colleagues who depend on rainfed maize and cassava. Rainfed farmers who switch to irrigated vegetables in the dry season can earn about US$300-500 per year. These urban and peri-urban farmers are examples of the booming informal irrigation sector in sub-Saharan Africa and supply nearly all of the perishable produce for urban consumption (about 1,350 tonnes of lettuce and 7,400 tonnes of cabbage per year in Kumasi). Due to the high profits, urban farming is the main and often only occupation of these farmers.

While the total farming area in the city is small (40–50 hectares under irrigation), there are about 11,900 hectares under dry season vegetable production in a 40 kilometer radius around Kumasi, cultivated by about 12,700 households. These plots are larger and have tenure security, farmers tend to be natives rather than migrants and are on average older (37 years) than those on urban plots. Up to 70 percent of the water comes from polluted streams and rivers (10<sup>3-6</sup> fecal coliforms), 21 percent from shallow dugouts, and 9 percent from other sources. Many dugouts are adjacent to the streams and are equally polluted. As in the city, watering cans are the most common irrigation tool.

The irrigated farming around Kumasi covers more than twice the area than is under formal irrigation in the rest of Ghana where in 22 irrigation schemes only about 5,600 hectares are farmed using irrigation. It is only in 2006, with support from FAO and IWMI, that the irrigation authorities and related ministries recognized the contribution of the informal irrigation sector in Ghana’s new national irrigation policy and strategy which was endorsed in 2009. The new policy recognizes the constraints of the informal sector, such as credit access, as well as its challenges, like the use of unsafe water in urban and peri-urban farming. It recommends to identify, evaluate and, where feasible, implement or disseminate promising and affordable technologies (including water treatment options) for making the most of specific local conditions and resource endowments for urban and peri-urban irrigation (Government of Ghana, 2010).

_Sources_ : Obuobie _et al_ ., 2006, Drechsel _et al_ ., 2007; Cornish and Lawrence, 2001.

_Wastewater irrigation in middle-income countries._ In the arid and semi-arid middle-income countries a common transition is observed: wastewater irrigation grows in scale because of increasing levels of sewerage and the gradual introduction of treatment. The unplanned direct use of untreated wastewater still occurs, but the following scenarios assume greater importance:

- The indirect and unplanned use of untreated effluents becomes a growing concern as cities discharge larger volumes of untreated effluents into nearby rivers with the resulting pollution of traditional irrigation sources (e.g., Santiago, Chile).

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