莱州湾南岸平原古河道及其与海(咸)水入侵关系研究

STUDY ON THE ANCIENT CHANNELS AND THE RELATIONSHIP BETWEEN THE ANCIENT CHANNELS AND THE SEA (SALT) WATER INTRUSION OF THESOUTH COASTAL PLAIN OF LAIZHOU BAY

海（咸）水入侵作为莱州湾南岸平原的一种新的环境灾害，其发生、发展与该区广泛分布的古河道密切相关。本文研究了古河道的分布规律、沉积特征及分期，并重点探讨了其与海（咸）水入侵的密切关系．古河道是该区海（咸）水入侵的主要通道，古河道中海（咸）水入侵速度快、方式多、周期性变化明显，是灾情最严重、入侵变化最复杂的地貌单元；古河道又是防治海（咸）水入侵的天然工程，古河道砂层径流条件好，只要采取措施提高其地下淡水水位，海（咸）水入侵界线就能迅速北退。

Sea(salt) water intrusion is a new environmental disaster in the south coastal plain of LaizhouBay, whose occurence and development are closely related to the widely-scattered ancient channels.This paper firstly studies the scattered patterns, the deposit features and the stages of the ancientchannels, then mainly probes into the relationship between the ancient channels and sea(salt)water intrusion. The ancient channels are the main passages of sea(salt) water intrusion. In the channels, the sea(salt) water intrudes rapidly in many wayS with distinct cyclical changes. The ancient channels aregeomorphologic unitS of the most serious diasters and the most complicated intrusion changes. At thesame time, the ancient channels are natural projects for prevention and control of sea (salt) water intrusion. The sandlayer of the ancient channels is favorable for runoff. Provided we take measures toraise the level of itS fresh water, the boundary line between sea (salt)water and fresh water will fallback rapidly.