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一、基本情况和历史水害里下河地区位于京杭大运河(里运河)以东、串场河以西、苏北灌溉总渠以南、通扬运河以北,是淮河下游沿海滨江的一块洼地,总面积一万一千多平方公里,耕地约九百五十万亩,以种植水稻为主。里下河地区地势低洼,河网密布,历史上排水主要东经四港(射阳港、黄沙港、新洋港、斗龙港)入海,路程远,受海潮和卤水倒灌,排水比降仅二、三十万分之一,排水模数每平方公里不足0.1秒立米,排水极其不畅;因此筑堤圈圩,逐步形成里下河圩区,圩区面积占总面积的百分之八十。里下河圩区四周高,中间低,象个“四水投塘”的锅底洼,不同地面高程的面积分配如表1
First, the basic situation and historical water damage Lixiahe area is located in the east of the Beijing-Hangzhou Grand Canal (Canal), west of the Cascade River, south of Northern Jiangsu irrigation canal, north of Tongyang Canal, is a depression along the coast of the Huaihe River, The total area of more than 11,000 square kilometers, about 9.5 million acres of arable land to grow rice-based. The Lixiahe area is low-lying and has a dense river network. Historically, the four main ports of the long-distance drainage such as Sheyang Port, Huangsha Harbor, Xin Yang Port and Dulong Port have long distances to the sea. Second, one hundred thousandth, the drainage modulus of less than 0.1 seconds per square kilometer cubic meters, drainage is extremely poor; so embankment circle Fair, and gradually formed in the river polder area, polder area of the total area of eight percent ten. Lixiahe polder area around the high, low in the middle, like a “water cast pond ” pot bottom depression, the distribution of different surface elevation area as shown in Table 1