基于水文水动力耦合模型的平原湖区土地利用变化对排涝模数的影响

Effects of Land-use Change on Drainage Modulus in Plain Lake Area Based on a Coupled Hydrological and Hydrodynamic Model

为准确模拟平原湖区土地利用变化对排涝模数的影响,选取湖北省四湖流域螺山排区作为研究区,利用构建的SCS-MIKE11耦合模型计算不同时期土地利用类型下的排涝模数,分析土地利用变化对排涝模数的影响,并通过设置不同水旱比、水面率和地面硬化率的组合,对土地利用变化条件下的排涝措施进行模拟优化。结果表明:在10 a一遇的1 d暴雨3 d排除和3 d暴雨5 d排除的标准下,2011年土地利用方式下求得的排涝模数比1994年求得的排涝模数大,分别增加了159.3%和33.6%;在保持水旱比和水面率不变的情况下,地面硬化率每增加1%,1 d和3 d暴雨下排涝模数分别增加0.005 m^3/(s·km^2)和0.003 m^3/(s·km^2);在保持水旱比和地面硬化率不变的情况下,水面率每增加1%,1 d和3 d暴雨下排涝模数分别减小0.016 m^3/(s·km^2)和0.012 m^3/(s·km^2);在保持水面率和地面硬化率不变的情况下,水旱比每增加0.1,1 d暴雨和3 d暴雨下排涝模数分别减小0.004 m^3/(s·km^2)和0.003 m^3/(s·km^2)。因此,除了增加排涝泵站的排涝流量外,减少地面硬化率(例如采用透水路面)、增加水面率和水旱比也是除涝减灾的有效措施。研究成果可为土地利用变化条件下平原湖区排涝模数的确定和排涝措施的制定提供参考。

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 m^3/(s·km^2) and 0.003 m^3/(s·km^2) 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 m^3/(s·km^2) 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 m^3/(s·km^2) and 0.003 m^3/(s·km^2) 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.