【作者】 王玮；

【导师】 徐东瑞；

【作者基本信息】 河北师范大学 ， 地图学与地理信息系统， 2010， 硕士

【摘要】 近年来,湖泊与环境关系的研究越来越受到人们重视。当前,湖泊科学的发展趋势是把湖泊及其流域作为一个整体进行研究,强调在人类活动影响下湖泊及其流域的演化。随着社会经济发展和人口数量增加,人类对流域的干扰活动日趋剧烈,在湖泊演化,尤其是在湖泊水量变化过程中,起着越来越重要的作用,其中土地利用/土地覆被变化是人类活动最直接的表现形式之一。张北湖泊群因受人类活动、气候的变化影响,湖泊群总水量逐年下降,湖泊面积不断萎缩,湖泊数量减少,对当地的生态环境、工农业生产,产生了不良影响。出现上述情况的主要原因在于当地土地利用方式的改变。通过建立研究区的数字高程模型,运用SWAT分布式水文模型,生成数字流域,划分出张北湖泊群流域的水文单元。以相同时期的TM影像为基本信息源,参考相关的专题图件,在GIS和RS的支持下,对不同时期张北湖泊群流域的土地利用信息进行解译,编制出两期土地利用现状图。建立研究区空间分布式水文模型,模拟该流域在不同下垫面和不同气候条件下水量变化情况。利用水量平衡原理,对湖泊水量变化与湖泊面积的关系进行了定量推导。通过对影响水量变化的自然及社会经济因子的分析,筛选出导致湖泊水量变化的驱动因子。在此基础上,建立了驱动因子与反映水量变化的湖泊面积的神经网络模型,并预测了未来5年湖泊演化的趋势。主要研究结论如下:(1)应用SWAT分布式水文模型对研究区域两个不同时期的径流量进行了模拟。经模拟验证,模拟结果较好的反映了流域径流的实际情况。研究结果表明:相同气象条件下,不同土地利用格局对湖泊水量变化影响有明显的影响,假定在同一气象条件下,研究区2008年湖泊群水量变化是1998年的2.27倍;相同土地利用格局,不同气象气象条件,2008年水量变化量是1998年的1.06倍;土地利用格局不同、气象条件不同, 2008年湖泊群水量模拟变化量是1998年的1.04倍,因湖泊群面积缩小,水位变化量是1998年的5.82倍。上述结果反映了土地利用格局改变、气象条件的变化都会影响湖泊群水量的变化。(2)研究区土地利用景观格局分析。结果表明:不同时间尺度下景观类型间的更替转化十分明显,尤其是由旱地向水浇地、林地、草地的更替及湖泊向内陆滩涂更替。在整个景观格局中,旱地始终占有优势地位,但自1998～2008年,旱地的连通性下降,整个斑块的破碎化程度增大。而水浇地的连接性增大,聚集度增高。说明研究区近十年来,退耕还林、还草的生态建设取得了一定的效果,水利工程建设和水浇地面积均有较大幅度增长,这也成为导致湖泊水面缩小、水量递减的主要原因。(3)运用回归分析方法,对研究区自然、社会经济因子与湖泊面积间的关系进行研究,以确定湖泊群水量变化的驱动因子。其回归方程为: Y=0.01395X1+0.09382X2-0.30281X3-0.20308X4-0.13027X5+0.39392X6,在a=0.0001水平下,相关系数R=0.998834,达极显著水平。通过权重分析机井数量、蔬菜产量、水浇地面积这三个反映社会经济条件的因子作为影响湖泊群水量变化的主导驱动因子。(4)利用神经网络建立机井数量、蔬菜产量、水浇地面积与湖泊面积的相互关系的非线性模型,并利用所建模型对该系统未来湖泊群水量变化趋势进行预测。经模型运算,到2015年湖泊面积将缩减到1599.907公顷,该结果比1998年减少了近9512公顷,比2008年减少了约2422公顷,1998年到2008年湖泊群面积的递减率709公顷/年,2008年到2015年湖泊面积的递减率346公顷/年。从总体上看湖泊群面积呈现逐年缩小的趋势,湖泊群水量的变化为负值,储水量也逐年减少。(5)在研究区,大湖泊的面积不断缩小,小湖泊趋于干涸。通过上述的研究可以确定人类活动是张北湖泊群演化的主导驱动因子,气候变化也有一定的影响。随着社会经济的发展和人口的增多,人类活动对自然的干扰会进一步增强,湖泊群生态环境恶化的趋势也会随之加剧。针对研究区所面临的湖泊水量日益减少、面积不断缩减,水资源匮乏的严峻现实,要采取一系列可持续发展对策,如:节约用水、控制机井数量、调整种植结构、节水灌溉等,以缓解当前的生态环境问题。更多还原

【Abstract】 Recently, researchers pay more attention to the study on the impact of lakes on the environment. At present, the development of the current science of lakes believed that lakes and drainage area should be regarded as a whole to research. It also pointed out that the evolution law of lakes and drainage area which is effected by human activity is the study orientation of lakes of geography. With economic development and population growth, human interfered with drainage areas violently. Human activity greatly influenced on the evolution of lakes and especially on the variation of water, while exploition of soil and covering of soil is the direct manifestation which is effected by human activity.Because of the influence of climate and human activity, the quantity of water, the area of lakes even the number of lakes in Zhangbei are decreasing. All these factors have bad effect on the industrial and agricultural production and ecosystem, while human’s exploition of soil and social activity are the major driving factors of this phenomenon.This study is based on digital elevation model and SWAT hydrology distribution model of study area is applied in this study in order to produce digital drainage area and show the hydrology units in Zhangbei drainage area. TM image of the same period which are regarded as the basic information source, together with the relevant special maps, in support of GIS and RS, explains the information of explition of soil of Zhangbei lakes at different stages and works out the current charts of exploition of soil in this two periods. Through SWAT model, the variation of water is worked out according to different underlying surface and different weather condition. Use of water balance principle to derivate the quantitative relationship between the changes of lake water and lake area. Changes affecting the amount of water through the natural and socio-economic factors analysis, filter out the driving factor which lead to changes in lake water. On this basis, use the neural network model reflect the establishment of the driving factors and changes in the lake water area,predict the trend of lake evolution in the next five years. The followings are the major research conclusions:(1) Application of SWAT Hydrological Model simulated two different times of the runoff for the study area. The simulation results better reflect the actual situation of runoff. The results show that: The same weather conditions, different land use pattern change have significant impact on lake water, assuming the same weather conditions in the study area, lakes water changes of 2008 is 2.27 times in 1998. The same land use pattern, different meteorological weather conditions, lakes water changes of 2008 is 1.06 times in 1998. Different land use patterns and weather conditions, water simulation of 2008 lakes variation is 1.04 times in 1998. Reduce the area for lakes, water level variation is 5.82 times of the 1998. These results reflect the pattern of land use changes, changes in weather conditions can affect changes in water lakes.(2) Analysis land use and landscape pattern of the study area. The results show that: the transformation is obvious in different time scales change between landscapes, especially those from the dry land to irrigated land, woodland, grass land and lakes inland beach replacement. Pattern throughout the landscape, the dry land always take advantage of the status. However, since 1998 ~ 2008, the dry land connectivity decline, and increase the piece of the fragmentation. The irrigated land increased connectivity, increased the aggregation. Description of the study area over the past decade, eco-construction has a certain effect in returning farmland to forest and grassland. The main reason which leading to decreasing water is water project construction and have a big increase in irrigated area.(3) Using regression analysis, study the relationship between regions factors socio-economic factors and the lake area, to determine the leading group driving of lakes water. The regression equation: Y=0.01395X1+0.09382X2-0.30281X3-0.20308X4-0.13027X5+0.39392X6In a = 0.0001 level, the correlation coefficient R = 0.998834, reached a significant level. Through analysis the weight of the number of motor-pumped well, vegetable production, irrigated area, which reflect the socio-economic conditions, affected the lakes of water as the dominant driving factor.(4) Using neural networks to nonlinear model of the relationship between lakes area and the number of motor-pumped well, vegetable production, irrigated area, to predict the future trend of lake water group. Through the model calculation,2015 lakes area will be reduced to 1599.907 ha. The results compared to 1998 decreased nearly 9512 hectares, compared to 2008 decreased nearly 2422 hectares. Decreasing rate of the area lakes is 709 ha/year from 1998 to 2008. Decreasing rate of lake area is 346 ha/year from 2008 to 2015. Whole lakes area reduced year by year, trend of changes in lake water for the negative group, reservoir water have gradually declined.(5) The current situation of Zhangbei lakes is that the decreasing area of big lakes and the drying up of small lakes. Human activity is the major driving factor that results in the drying up of lakes. Climate change also has some influence. With the socio-economic development and population increase, the interference of human activities on further enhancing the natural, lakes deterioration of ecological environment would be more intensive.The following measures are effective to solve the problems such as the area decreasing of the lake, the quantity of water and the number of lakes. Saving water, limitation of the power-operated wells, adjusting the planting structure and appropriate irrigation are beneficial to alleviate current ecological problems of Study area.更多还原