【摘要】：鹽沼地排泄的來自內(nèi)陸的地下水是營(yíng)養(yǎng)物或者污染物的重要載體。分析地下水-地表水的相互作用機(jī)理對(duì)研究鹽沼地潮間帶的植物長(zhǎng)勢(shì)、分布及種類的研究具有重要實(shí)際意義。2013年夏季我們?cè)诔缑鲘u北岸選了一個(gè)長(zhǎng)1km,在高潮時(shí)能全部淹沒,并生長(zhǎng)著不同植物的剖面,在剖面上埋設(shè)5口監(jiān)測(cè)井,監(jiān)測(cè)地下水水位、溫度及電導(dǎo)率,監(jiān)測(cè)頻率為1小時(shí)1次,距離江水和內(nèi)陸最近的兩口井持續(xù)監(jiān)測(cè)一年,其他三口井持續(xù)一個(gè)月。通過野外觀測(cè)和監(jiān)測(cè)數(shù)據(jù)的分析發(fā)現(xiàn),土壤飽和程度與植物種類分布有很好的相關(guān)性：即蘆葦生長(zhǎng)在潮間帶的上部,該處土壤都是非飽和的,而互花米草生長(zhǎng)的區(qū)域的表層土壤幾乎都是飽和的,說明植物分區(qū)生長(zhǎng)與地下水有緊密聯(lián)系。另外,長(zhǎng)期數(shù)據(jù)表明地下水溫度和電導(dǎo)率在年際變化上存在很好的正相關(guān)性。我們運(yùn)用二維垂直剖面有限元數(shù)值模擬程序MARUN對(duì)野外一個(gè)月的數(shù)據(jù)進(jìn)行模擬和擬合。通過野外實(shí)際觀測(cè)和參考近期文獻(xiàn),將研究剖面分成兩層,即垂向滲透系數(shù)(10-7m/s)極小的粘土表層(厚度為0-3m)和垂向滲透系數(shù)(10-Sm/s)較大的底層(厚約22m),上下層橫向和縱向滲透系數(shù)的各向異性比分別為1和3,其中表層存在兩個(gè)較大的地形轉(zhuǎn)折點(diǎn)。數(shù)值模擬結(jié)果表明,通過剖面表層平均流速的計(jì)算,在大小潮期間地下水的排泄量為0.33 m3m-1d-1,其中來自內(nèi)陸的淡水為0.21 m3m-1d-1。地下水的排泄區(qū)集中在離內(nèi)陸400米到1000米的區(qū)域內(nèi),地下水的入滲區(qū)集中在離內(nèi)陸180米到400米的地方,地下水的排泄區(qū)和江水入滲區(qū)分別是互花米草和蘆葦生長(zhǎng)的區(qū)域,兩者的交換速率在地形突變點(diǎn)達(dá)到最大,表明地形對(duì)整個(gè)地下水的循環(huán)起著很重要的作用。在排泄區(qū),垂直于表層的平均流速為4 mm/d,入滲區(qū)的平均流速為3 mm/d。最后,我們用圖形的方式概化了鹽沼地地下水-江水循環(huán)系統(tǒng)模式。
[Abstract]:Groundwater discharged from inland salt marshes is an important carrier of nutrients or pollutants. The analysis of the interaction mechanism between groundwater and surface water is of great practical significance for the study of plant growth, distribution and species in the intertidal zone of salt marshes. In summer 2013, we selected a 1km long one on the north shore of Chongming Island, which can be completely submerged at high tide. Five monitoring wells were planted in the profile to monitor the groundwater level, temperature and conductivity. The monitoring frequency was 1 hour, and the two wells closest to the river water and inland were monitored continuously for one year. The other three wells lasted for a month. Through the analysis of field observation and monitoring data, it is found that the soil saturation degree has a good correlation with the distribution of plant species: the Reed grows in the upper part of the intertidal zone, where the soil is unsaturated. However, the surface soil of Spartina alterniflora growing area is almost saturated, indicating that the growth of plant zoning is closely related to groundwater. In addition, long-term data show that there is a good positive correlation between groundwater temperature and conductivity. The data of one month in the field are simulated and fitted by the finite element simulation program MARUN. Based on field observations and recent references, the study profile is divided into two layers. That is, the surface layer (0-3m thickness) with minimal vertical permeability coefficient (10-7m/s) and the lower layer (about 22m thick) with larger vertical permeability coefficient (10-Sm/s) have anisotropy ratios of 1 and 3 respectively. A great turning point in the terrain. The numerical simulation results show that the groundwater discharge is 0.33 m ~ (-3) m ~ (-1) d ~ (-1) and 0.21 m ~ (-3) m ~ (-1) d ~ (-1) for fresh water from inland during the period of large and small tide. The drainage zone of groundwater is concentrated in the area of 400m to 1000 meters from the inland, and the infiltration zone of groundwater is concentrated in the area of 180-400m from the inland. The discharge zone of groundwater and the infiltration zone of river water are the growing areas of Spartina alterniflora and Reed, respectively. The exchange rate of the two is maximum at the abrupt point of topography, which indicates that topography plays an important role in the circulation of the whole groundwater. In the drainage zone, the average velocity perpendicular to the surface is 4 mm/d, the average velocity of infiltration is 3 mm/d.. At last, we generalize the model of groundwater-river circulation system in salt marsh.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P641.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 戰(zhàn)慶;王張華;王昕;李曉;;長(zhǎng)江口區(qū)晚新生代沉積物粒度特征和沉積地貌環(huán)境演變[J];沉積學(xué)報(bào);2009年04期

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本文編號(hào)：2233540