Research On The Recharge Of Groundwater Affected By Urban Expansion In Jinan City

Jinan is known as a history culture city for springs in the world, the dynamic varieties of the spring water-table have got an important influence in the economy, environment of Jinan city. In recent twenty years, the reasons are various that the spring-supply and time reduce continuously. Many scholars and organizations have done many works on the spring of Jinan, especially in the aspects of recharge of groundwater in Jinan , and put forward that the urban expansion has the influence in recharge of the groundwater. This paper is based on the investigation of the fore people, makes use of 3S technologies, analyzes the bottom mat changed from the city expansion, which causes the fall of groundwater level. The result expresses: it is a science standpoint that urban expansion is one of the main reasons to cause the decreasing of supply to groundwater.The range of research: the boundary of Jinan between Changqing county is the west boundary, the mountain range of the Great Wall watershed is the south boundary, the Dongwu fracture is the east boundary, the hand over boundary of anthracolithic system and igneous rock is the north boundary. The whole research scope locates inside the spring field of Jinan, and area is about 1003.5 Square Kilometers. This work is founded on fore research, by hydrology, hydrology geology theories, on collecting the domestic and international relevant data and the relevant research result, proofing the relations between recharge of ground-water and the bottom mat types. The paper extracts information of the study field by 3S technologies, then converts space information as the hydrology information, according to the three water conversion relates in the study field, calculates the reduce from recharge of groundwater: the reduce from recharge of precipitation, the reduce from recharge of surface water, the reduce from recharge of irrigation water, at last gets quantitative dates. The Main research results:l.The paper confirms reasonably the different coefficients of recharge from precipitation as the different bottom mats by adopting to change coefficient method.2. On the analysis and calculation, the paper verifies the science judgment that urban expansion has influence in recharge from groundwater.3. The research result expresses: From 1995 to 2000 years, the urban expansion causes to the reduce in recharge of groundwater annually; Between 1995 and 1998 years, the recharge of groundwater decreases 2,319,000 square; between 1998 and 2000 years, the recharge of groundwater decreases 2, 884,000 square.4. From changes of the bottom e mat types, it is a main factor to affect the groundwater replenishment that the farmland is turned into the urban, the lawnis the next in order. From this, the urban expansion should avoid taking up farmland possibly. It is the valid method to add supply to underwater by afforesting.5. The pace of urban expansion relates closely to topography. The plain, mound is the main region turned to urban, so reduce of recharge from precipitation is the largest in the plain, mound.6. It is the available means to analyze the variety regulation of urban expansion from the different meantime and angle by 3S technologies. The recharge of underground water is affected by the geography, land use, precipitation etc, for elemental huge data, the traditional method is impossible to attain the synchronous, accurate, in time date. Using only three images of remote sensing, the bottom mat information can be accurately extracted.7. Experiment datas done are the foundation of the paper. It is impossible to get the reasonable and accurate research results without the fore experiment datas. Therefore the traditional research means are indispensable, only blending modern technique with the traditional research method together, it is possible to increase the study level.