Effects Of Reclamation On Marine Environment In Dalian Lingshui Bay

With rapid development of urbanization and marine economy in recent years, the original land area has failed to meet the requirements of urban construction. Depending on the advantages of geographical location, many coastal provinces and cities in our country deprive land from sea by reclamation. Though reclamation can bring large benefit to our economy, it may partly damage the bay environment at the same time. Bay is the sea that in-depth land and in sharp curved, bearing double impacts from both the land and the sea. During the development and construction in the bay, reclamation will lead to bay area reduction and weaken the self-purification capacity of the bay, which has resulted in the increasingly serious environment pollution and hence has become more focus on environmental studies.In order to study the impact of reclamation on surrounding environment in the bay, this paper takes the reclamation work in Dalian Lingshui Bay as the research object. This dissertation adopts the way of tidal current field simulation around the project to study the impact of reclamation on hydrodynamic conditions and diffusion of nitrogen and phosphorus besides the impact on erosion and deposition environment. Meanwhile, the reclamation’s impact on marine ecological environment was also studied by means of laying 14 water station sites,5 sediment stations, and 5 biological stations and by comparing with the original status before the project construction.Numerical simulation of tidal current field states that the reclamation has changed the trend movement from original reciprocating flow to rotating flow, it hinders the diffusion of nitrogen and phosphorus and brings about deposition. Result of the water quality comparison indicates that the max concentration of inorganic phosphorus and inorganic nitrogen is at 1257.05μg/L and 236.05μg/L after the project construction, with the maximum appearing in top water of the bay and nitrogen and phosphorus concentrations in some stations can fulfill the fourth level of seawater quality standards, however, the max concentration of inorganic phosphorus and inorganic nitrogen is 192.8μg/L and 68.72μg/L before the project construction.Comparison on sediment data shows that the project brings an increase in heavy metals of the surface sediments. The exceeding rate of Cu in sediment changes from 0 to 40%after the construction, while Zn changes from 0 to 40%and TOC changes from 14.3%to 40%. Biological comparison results demonstrate that the average indicator of phytoplankton diversity reduces from 2.562 to 1.622 after the reclamation, and average indicator of zooplankton diversity decreases from 3.056 to 2.704.In summary, the land reclamation changes the hydrological dynamic and scour condition of Lingshui Bay, resulting in diminished capacity of water exchange. Also, pollutants cannot be diffused outside by sea-proliferation, especially in the top water of Lingshui Bay, so eutrophication appeared in some stations of peripheral waters, in the meantime, interaction between heavy metals and suspended solids results in the augment of heavy metals’content in sediment. Changes of water quality and sediment affect the existence of marine life and damage the structure of biological communities on a certain degree. Based on the results of investigation and analysis of Lingshui Bay, recommendations on scientific planning and management were proposed to reduce the effects on marine environment by reclamation.