四湖流域下垫面改变对排涝模数的影响

Effects of underlying surface changes on drainage modulus in Four-lake Watershed

选取湖北省四湖流域螺山排区作为研究对象,利用经验公式法计算排涝模数,并分析水面率、水旱比、城市化和灌溉方式及其变化对排涝模数的影响。结果表明:排涝模数随着水旱比和水面率的增加而减小,而随着地面硬化率的增加而增大;水面率对排涝模数的影响大于水旱比和地面硬化率的影响;同水稻的传统灌溉相比,间歇灌溉下的排涝模数较小。由于下垫面条件的改变,在10年一遇3日暴雨的排涝标准下,该地区排涝模数由1994年的0.38m3/(s·km2)上升到2011年的0.46m3/(s·km2),大约相当于1994年下垫面条件下的19年一遇3日暴雨的排涝标准。

This study takes the Luoshan drainage area in Four-lake Watershed in Hubei Province as an example. The drainage modulus is calculated with an empirical formula. The effects of water surface ratio, proportion of paddy field to dry land area, urbanization, irrigation mode and underlying surface changes on the drainage modulus are analyzed. Results show that the drainage modulus decreases with an increase in the proportion of paddy field to dry land area, and decreases with an increase in the water surface ratio, as well as increases with an increase in ground hardening rate. In addition, the effects of water surface ratio on the drainage modulus are greater than those of the proportion of paddy field to dry land area, and the ground hardening rate. The drainage modulus is smaller with intermittent irrigation than that with traditional irrigation. Based on the water logging control standard of a three day rainstorm with a 10 year return period, the drainage modulus had increased from 0.38 m^3/（ s·km^2） in 1994 to 0.46 m^3/（ s· km^2） in 2011 because of underlying surface changes. In 2011, the drainage modulus met approximately the water logging control standard for a three day rainstorm with a 19 year return period, based on the underlying surfaces in 1994.