發(fā)布時(shí)間：2018-03-31 03:32

  本文選題：黃土高原　切入點(diǎn)：地下水補(bǔ)給　出處：《西北農(nóng)林科技大學(xué)》2017年碩士論文

【摘要】：丘陵溝壑區(qū)為高土高原主要的地形地貌單元。土層深厚、地下水埋深大以及嚴(yán)重的坡面侵蝕等特點(diǎn)為黃土高原創(chuàng)造了特殊的水文過程。坡地在黃土高原乃至全世界的分布都非常廣泛,其地下水研究以及降雨徑流過程既復(fù)雜、難以理解,也極其重要,對(duì)理解地下水的補(bǔ)給以及河流溝道的排泄重要的作用。在黃土高原,坡地將降雨分為側(cè)向的坡面徑流和垂直的土壤水入滲。穿過植物根層的降水將補(bǔ)給到地下水;而坡面徑流、流域儲(chǔ)存的地下水以及土壤水在流域出口處匯合,進(jìn)而達(dá)到對(duì)溝道溪水的補(bǔ)給。地下水補(bǔ)給關(guān)系到區(qū)域水資源的可持續(xù)發(fā)展以及水資源的可更新能力,同時(shí)也關(guān)系到人類的用水安全。了解黃土高原坡地的地下水補(bǔ)給通量以及補(bǔ)給方式,有助于我們更好的評(píng)估深層土壤水的運(yùn)移方式以及區(qū)域地下水水資源量,從而為黃土高原的生態(tài)水文和土壤水文提供理論支撐。我們猜想:在研究區(qū)黃土高原丘陵溝壑區(qū)坡地,非飽和帶的地下水主要補(bǔ)給方式為活塞流,同時(shí)其補(bǔ)給量很微小,但是卻很重要。為了印證這個(gè)猜想,在2014年和2015年半干旱和半濕潤(rùn)流域的坡地上,我們共進(jìn)行了7個(gè)深剖面土壤取樣(15~20 m不等)。通過核爆后黃土高原土層中顯著的的氚坡面來示蹤坡地地下水補(bǔ)給及其控制因素。結(jié)果表明:每一個(gè)土層中都呈現(xiàn)良好的鈴形氚剖面,顯示出土壤水運(yùn)移主要以活塞流的方式。氚峰值在半干旱的清澗園則溝流域位于9.3~11 m,在半濕潤(rùn)長(zhǎng)武王東溝流域?yàn)?.3~7.2 m。7個(gè)剖面補(bǔ)給速率變化為22.9~31.9 mm yr~(-1),達(dá)到長(zhǎng)期降水量的4%~7%,約為典型平地的54%。地下水補(bǔ)給主要是受土壤質(zhì)地以及土地利用方式的影響,受到區(qū)域氣候的影響較為微弱。在全世界,對(duì)土層深厚、植被覆蓋度較低的流域徑流來源的研究較少。國內(nèi)外的研究表明流域儲(chǔ)存的老水對(duì)溝道徑流有著重要的貢獻(xiàn),在土層淺薄區(qū)域地下徑流占有主導(dǎo)優(yōu)勢(shì)。我們選取黃土高原丘陵溝壑區(qū)作為研究對(duì)象,通過同位素(~2H)和水化學(xué)示蹤劑(Cl~-、SO_4~(2-))來探究降水以及流域儲(chǔ)存的深層土壤水或者地下水對(duì)溝道溪水的貢獻(xiàn)。通過6場(chǎng)不等強(qiáng)度的降水、溪水的連續(xù)取樣,及流域降雨前泉水和基流水取樣分析,結(jié)果表明溪水的主要成分為降水,示蹤劑的計(jì)算結(jié)果表明降水對(duì)溪水的最大貢獻(xiàn)可以高達(dá)100%(~2H)以及75%(Cl~-和SO_4~(2-))。溪水的同位素隨著降水有明顯的波動(dòng),這表明了坡面的超滲產(chǎn)流過程主導(dǎo)研究區(qū)流域的徑流過程。水化學(xué)示蹤劑的研究表明溝道溪水多余的Cl~-來源于降水對(duì)土壤的表層礦物質(zhì)溶解等過程。相對(duì)于同位素示蹤劑,水化學(xué)示蹤劑的結(jié)果會(huì)低估降水對(duì)徑流水的貢獻(xiàn)。本文的研究為黃土高原丘陵溝壑區(qū)徑流的形成機(jī)制以及退耕還林還草對(duì)于流域水文過程的影響提供一定的參考價(jià)值。
[Abstract]:The hilly and gully region is the main topographic and geomorphologic unit in the high soil plateau.The characteristics of deep soil layer, deep groundwater and serious slope erosion have created special hydrological process for the Loess Plateau.Slope land is widely distributed on the Loess Plateau and all over the world. The study of groundwater and the process of rainfall runoff are complicated, difficult to understand, and extremely important, which plays an important role in understanding the recharge of groundwater and the discharge of rivers and ditches.On the Loess Plateau, rainfall is divided into lateral runoff and vertical infiltration of soil water.The precipitation through the plant root layer will recharge to the groundwater, while the runoff on the slope, the groundwater stored in the basin and the soil water will converge at the outlet of the basin to recharge the channel stream water.Groundwater recharge is related to the sustainable development of regional water resources, the renewable ability of water resources, and the water security of human beings.Understanding the groundwater recharge flux and recharge mode of sloping land on the Loess Plateau is helpful for us to better evaluate the migration mode of deep soil water and the amount of regional groundwater resources.Therefore, it provides theoretical support for ecological hydrology and soil hydrology in the Loess Plateau.We conjecture that in the slope of hilly and gully region of the Loess Plateau the main recharge mode of groundwater in unsaturated zone is piston flow and its recharge is very small but very important.In order to verify this conjecture, in 2014 and 2015, on the slopes of semi-arid and sub-humid watersheds, we have carried out seven soil samples of 15 ~ 20 m in deep profile.The significant tritium slope in the soil layer of loess plateau after nuclear explosion was used to trace groundwater recharge of slope land and its controlling factors.The results show that there is a good bell-shaped tritium profile in each soil layer, which shows that the water transport of the soil is mainly in the form of piston flow.The peak value of tritium in Qingjianzigou watershed is 9.310m, and in the sub-humid Wangdonggou basin of Changwu, the supply rate of 7.7mm ~ 31.9 mm ~ (-1) ~ (-1) is 22.9m ~ 31.9 mm ~ (-1) ~ (-1), which is about 54.45% of the long-term precipitation, which is about the same as that in typical flat land.Groundwater recharge is mainly affected by soil texture and land use patterns, but by regional climate.In the world, there are few researches on the runoff sources with deep soil layer and low vegetation coverage.Studies at home and abroad show that the old water stored in the watershed plays an important role in channel runoff and dominates the underground runoff in shallow soil areas.We select the hilly and gully region of the Loess Plateau as the research object and explore the contribution of precipitation and the deep soil water or groundwater stored in the basin to the gully stream by means of the isotopic isotope (2H) and the hydrochemical tracer (ClCl-so _ 4).The main components of stream water are precipitation, the continuous sampling of stream water, and the sampling analysis of spring water and Ji income before rainfall, the results show that the main component of stream water is precipitation.The results of tracer calculation show that the maximum contribution of precipitation to stream water can be as high as 100 ~ 2H) and 75 ~ (-) Cln- and so _ (4) ~ (-) ~ (2).The isotopes of stream water fluctuate obviously with precipitation, which indicates that the process of overosmotic runoff on the slope dominates the runoff process in the study area.The study of hydrochemical tracer shows that the excess Cl- in channel stream water originates from the process of precipitation dissolution of surface minerals in soil.Compared with isotopic tracers, the results of hydrochemical tracers underestimate the contribution of precipitation to runoff water.The research in this paper provides a certain reference value for the formation mechanism of runoff in the hilly and gully region of the Loess Plateau and the effect of returning cropland to forest and grass on the hydrological process of the watershed.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P333;P641

【相似文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前2條

1 陶澤;基于同位素和水化學(xué)示蹤劑的黃土高原小流域徑流來源和地下水補(bǔ)給[D];西北農(nóng)林科技大學(xué);2017年

2 胡書勇;單井化學(xué)示蹤劑法測(cè)殘余油飽和度數(shù)值模擬研究[D];西南石油學(xué)院;2003年

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本文編號(hào)：1688980