Saltwater intrusion or encroachment is a major environmental geological hazard, which is defined as the migration of salt water into freshwater aquifers under the influence of groundwater development (1). Saltwater intrusion becomes a problem in coastal areas where freshwater aquifers are hydraulically connected with seawater. The salinization of the freshwater resources has seriously impeded the development of agriculture and industry and the improvement of the peoples' living standards in these areas. In the mid-1980s, the overexploitation of groundwater exacerbated the saltwater intrusion, and the rate of intrusion continues to increase steadily (2). The Laizhou Gulf, located in Shandong Province of China, is one of the places experiencing serious saltwater intrusion (Fig. 1), Although many studies have focused on groundwater hydro-chemical characteristics (3), causes and prevention countermeasures (4), and sea-water intrusion disaster (5) in the Laizhou Gulf, causes and impacts in the area of saltwater intrusion have received little attention. The objective of this study is the analysis of the causes of saltwater intrusion and its impact on the coastal areas of the Laizhou Gulf. The study area (36 deg 51 min-37 deg 30 min N and 118 deg 38 min-119 deg 36 min E) is located in the northern part of the southern coastal plain of the Laizhou Gulf, Shandong Province, China, with an area of 3772 km~2 (Fig. 2). In the study area, the average annual temperature is 11.5-13 deg C, and the average annual precipitation is 628.6 mm; 70-80 percent of the year's total precipitation comes during June to August. The average annual evaporation is about 1640 mm, chiefly during April to June. The land surface of the study area slopes gently from south to north and is made up of an alluvial and diluvial plain, an alluvial and marine plain, and a marine plain; these are distributed from south to north, respectively. Accordingly, the study area is classified into three type zones from south to north: a freshwater zone with an area of 1158 km~2; a fresh- and saltwater zone with an area of 525 km~2; and a saltwater zone with an area of 2089 km~2.
展开▼
