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Rice production is important for global food security but given its large water footprint, efficient irrigation management strategies need to be developed. Expansion of rice growing area is larger than any other crop in Africa due to increasing demand for rice. Three rice irrigation management alternatives with the system of rice intensification (SRI) were field-evaluated against the conventional continuously flooded system (CF) in Tanzania. Production systems included: (1) CF (50 mm ponding depth for the entire season); (2) SRI (40 mm ponding for 3 days and no irrigation for next 5 days); (3) 80% SRI (80% of the SRI ponding); and (4) 50% SRI (50% of the SRI ponding). Experimental evaluation of the four systems was conducted for both wet and dry seasons. For the dry season, the SRI and 80% SRI produced higher yields of 9.68 tons/ha and 11.45 tons/ha and saved 26% and 35% of water, respectively compared to the CF (8.69 tons/ha). The yield advantage of the 80% SRI and SRI over the CF was less during the wet season with 6.01 tons/ha and 5.99 tons/ha of production, and water savings of 30% and 14%, respectively compared to the CF (5.64 tons/ha). The 50% SRI had lowest yield of all for both seasons, 7.48 tons/ha and 4.99 tons/ha for the dry and wet seasons, respectively. Statistically, the 80% SRI treatment outperformed all other treatments over the two seasons with an additional yield of 1.57 tons/ha and 33% (345 mm) water savings compared to the CF. Economic productivity of water (US$/ha-cm) over two seasons was highest for the 80% SRI ($20.27/ha-cm), while it was lowest for the CF ($12.89/ha-cm). Water saved by converting from the CF to the 80% SRI (1.98 million ha-cm) can support a 50% expansion in the current rice irrigated area in Tanzania. Even without irrigation expansion, the 80% SRI can increase rice production by 1.5 million tons annually while enhancing water availability for industrial and environmental uses (e.g., ecological preserves) and help achieve food security in Tanzania and the greater sub-Saharan Africa.

This paper focuses on the application of the concept of Integrated Water Resources Management (IWRM) in Tanzania. It asks: how did IWRM affect the rural and fast-growing majority of smallholder farmersʼ access to water which contributes directly to poverty alleviation and employment creation in a country where poverty and joblessness are high? Around 1990, there were both a strong government-led infrastructure development agenda and IWRM ingredients in place, including cost-recovery of state services aligning with the Structural Adjustment Programmes, water management according to basin boundaries and the dormant colonial water rights (permits) system. After the 1990s, the World Bank and other donors promoted IWRM with a strong focus on hydroelectric power development, River Basin Water Boards, transformation of the water right system into a taxation tool, and assessment of environmental flows. These practices became formalised in the National Water Policy (2002) and in the Water Resources Management Act (2009). Activities in the name of IWRM came to be closely associated with the post-2008 surge in large-scale land and water deals. Analysing 25 years of IWRM, the paper identifies the processes and identities of the losers (smallholders and-at least partially-the government) and the winners (large-scale water users, including recent investors). We conclude that, overall, IWRM harmed smallholdersʼ access to water and rendered them more vulnerable to poverty and unemployment.