New Delhi: Delhi govt Friday approved projects worth Rs 622 crore to strengthen the city’s drainage and flood management system, including a 4.7 km reinforced cement concrete wall along the vulnerable stretch of Yamuna and three biomining projects to scientifically dispose of silt removed from drains. The decisions were taken at the 40th meeting of the flood control board, chaired by irrigation and flood control minister Parvesh Verma at Delhi Secretariat. The Rs 99-crore RCC wall will be built along Yamuna between Magazine Road drain and Old Railway Bridge to protect low-lying areas during high water levels. The board also gave in-principle approval to three biomining projects worth Rs 260 crore to address the long-standing problem of silt disposal. Beautification of drain stretches was also discussed at the meeting.