Research On The Seawater Incursion Control And Treatment For The City Of Laizhou The Wanghe River Down Stream Region

The Wanghe River down stream region provides the most important fresh water resource for city of Laizhou. Industry and agriculture productions have grown rapidly with more and more reform and open-door policies are introduced. This leads to the significant increase of demand for fresh water. The Wanghe River down stream region underground water level is getting lower year by year. Also, due to the upper stream water reservoir project and two severe droughts which both lasted 4 year long since 1977, minus water level values have been recorded in the Binhai plain region. As time goes by, three big series of bead like dripping regions parallel to the sea line have come into being. These minus water level areas increase the seawater incursion speed toward the inland. The seawater incursion deteriorated underwater quality, destroyed ecological balance, constrained industry and agriculture production and endangered people's living. The situation is very serious.This project is funded by Japanese OECF loan. It is to research on the seawater incursion control and treatment for the Wanghe River down stream region. From the long run, water transfer from other region is the best solution for Laizhou's fresh water resource problem. But this is difficult to realized due to various reasons. Building an underground reservoir at the Wanghe River down stream region can block the surface water run off and redirect it to underground water supply. This way, the underground water resource can be fully utilized with the underground reservoir' s multi-year water supply adjustment capability. With this approach, fresh water resource can be shared between wet and dry years, more underground fresh water canbe saved and used, and the seawater incursion can be effectively controlled. This is the best approach to solve city of Laizhou' s water resource shortage and seawater incursion problem.This paper includes eight parts. The first part explains the reasons of sea water incursion at the Wanghe River down stream region; The second part is for the geological condition of the Wanghe River down stream region; The third part is for the underground water geological condition; The fourth part is for the underground reservoir water storage condition; In the fifth part, underground reservoir water amount balance is calculated; In the sixth part, the underground reservoir water flow dynamic condition is analyzed and forecasted; In the seventh part, geological engineering conditions for the underground reservoir structure are discussed. In the eighth part, the underground reservoir's environmental impact is discussed.In order to analyze and prove the feasibility of underground reservoir for the Wanghe River, engineering survey, drilling exploration, digging exploration, pressure water experiment, stable and unstable water flow sucking experiment, underground water dynamic observation, and radio active element testing are used. Through on site work, the Wanghe River down stream region geological conditions, underground geological conditions and underground reservoir water storage conditions and parameters are obtained and mathematical models were established for simulation. Then underground reservoir water amount balance is calculated and the underground reservoir water flow dynamic condition is analyzed and forecasted. Through the above work, the following conclusions are made:1. Currently, building the underground reservoir for the Wanghe River is the most effective approach to prevent the Wanghe River down stream seawater incursion, increase underground water resource availability, improve water quality, and protect ecological environment.2. The fanghe River underground reservoir region foundation base and surrounding border are well set. Therefore, underground water blockage dams are only needed on the reservoir' s north border, west border, and water exit west end of south border. The underground reservoir contains widespread and thick 4th category loose sand layer. This sand layer has excellent water seepage, absorption. There exists c...