Abstract: An SCS-MIKE11 coupled model was built to calculate the drainage moduli of plain lake area with different land-use patterns, and the effect of land-use change on drainage modulus was analyzed. Drainage measures in the background of land-use change were simulated and optimized by setting different combinations among proportions of paddy field to dry land area, water surface ratio, and ground hardening rate. The Luoshan drainage area in the Four-lake Drainage Basin in Hubei Province was selected as study area. Results revealed that the drainage modulus in 2011 was larger than that in 1994 under the same land-use pattern. According to the water logging control standards (10-year rainstorm for one day and draining for three days, 10-year rainstorm for three days and draining for five days), the drainage modulus increased by 159.3% and 33.6% respectively from 1994 to 2011. When water surface ratio and proportion of paddy field to dry land area kept unchanged, the drainage modulus under one-day rainstorm and three-day rainstorm increased by 0.005 m³/(s·km²) and 0.003 m³/(s·km²) respectively as ground hardening rate increased by 1%; the drainage modulus under one-day rainstorm and three-day rainstorm decreased by 0.016 m³/(s·km²) and 0.012 m³/(s·km²) as water surface ratio increased by 1% when ground hardening rate and proportion of paddy field to dry land area kept unchanged; the drainage modulus under one-day rainstorm and three-day rainstorm decreased by 0.004 m³/(s·km²) and 0.003 m³/(s·km²) as proportion of paddy field to dry land area increased by 0.1 when ground hardening rate and water surface ratio remained unchanged. Therefore, reducing the ground hardening rate by permeable pavement for example, and increasing the water surface ratio and proportion of paddy field to dry land area in addition to increasing the drainage discharge of pumping stations are effective measures of reducing waterlogging disaster loss. The research results could be used as a reference for reasonable determination of the drainage modulus and formulation of waterlogging control measures under the condition of land-use change in plain lake areas.

Key words: plain lake area, drainage modulus, land-use patterns, SCS model, MIKE11 model