本文選題：SWAT模型 + 生態(tài)修復(fù)��； 參考：《蘭州大學(xué)》2015年碩士論文

【摘要】：白龍江流域是我國水土流失嚴(yán)重和泥石流災(zāi)害高發(fā)地區(qū)之一,生態(tài)修復(fù)是改善白龍江流域脆弱生態(tài)環(huán)境、防治水土流失和泥石流災(zāi)害的重要手段,對不同生態(tài)修復(fù)模式的修復(fù)效應(yīng)進行模擬研究是該流域開展生態(tài)修復(fù)的重要科學(xué)依據(jù)。本文選用基于物理機制的SWAT分布式水文模型及其情景模擬法,從地表生態(tài)水文過程的角度出發(fā),選用地表徑流深度這一關(guān)鍵指標(biāo),對不同生態(tài)修復(fù)模式下白龍江流域徑流變化進行了模擬分析,并進一步以白龍江流域典型泥石流溝——構(gòu)林坪小流域為例,基于泥石流啟動的地表徑流深度閾值,分析了不同生態(tài)修復(fù)方式對該流域泥石流災(zāi)害的防災(zāi)減災(zāi)效應(yīng)。主要結(jié)論如下：(1) SWAT模型適用于白龍江流域。通過對白龍江流域中游武都水文站和下游碧口水文站的流量進行率定和驗證,效率系數(shù)和相關(guān)系數(shù)均達(dá)到了SWAT模擬的基本要求,能夠客觀準(zhǔn)確地模擬白龍江流域地表徑流深度以及徑流量。(2)通過SWAT模型參數(shù)的敏感性分析,得到對白龍江流域的徑流有較大影響的參數(shù),主要包括CN2(徑流曲線系數(shù))、SURLAG(地表徑流滯后系數(shù))、CH K2(主河道水力傳導(dǎo)率)等。(3)白龍江流域的泥石流災(zāi)害生態(tài)修復(fù)效應(yīng)模擬。本文以國家退耕還林還草政策為基礎(chǔ)設(shè)計了35種生態(tài)修復(fù)模式(情景),包括5種極端模式(情景)和30種合理模式(情景)。(4)分析了5種極端模式下的流域年均地表徑流深度變化情況,結(jié)果顯示,全部耕地退耕為常綠林的生態(tài)修復(fù)情景對降低該流域地表徑流深度最為有效,下降率達(dá)到12.79%,生態(tài)修復(fù)效果最佳。然后從月時間尺度分析了極端情景下的月均地表徑流深度變化情況,與基準(zhǔn)情景的地表徑流深度相比,各極端情景的地表徑流深度為全年整體下降,沒有出現(xiàn)個別月份地表徑流深度上升的情況,說明本模擬結(jié)果具有較高的準(zhǔn)確度。(5)分析了30種合理情景下的白龍江流域年均地表徑流深度變化情況。結(jié)果顯示：在退耕后植被類型相同時,對坡度大于15度耕地進行退耕,其對地表徑流深度的減少程度次于耕地全部退耕的極端情景,但是高于坡度大于25度耕地退耕的情景。結(jié)合退耕面積進行分析,結(jié)果顯示,對坡度大于15度的耕地進行退耕的修復(fù)情景減少地表徑流深度的效率最高,以退耕為常綠林的情景為例,平均每退耕1km2耕地,流域地表徑流深度下降0.0095mm。最后分析了不同坡度級別退耕不同植被類型的情景,結(jié)果顯示,退耕類型為常綠林和灌叢的組合時,地表徑流深度下降幅度最大。(6)構(gòu)林坪流域的泥石流災(zāi)害生態(tài)修復(fù)效應(yīng)模擬。以國家退耕還林還草政策為基礎(chǔ),結(jié)合流域的自然植被的分布規(guī)律,設(shè)計了9種生態(tài)修復(fù)模式(情景)。分析各情景下的年均地表徑流深變化情況,結(jié)果顯示,對構(gòu)林坪小流域而言,耕地退耕為林地的修復(fù)情景效果最明顯,年均地表徑流深度下降了21.15%,其次是林地與灌叢的組合修復(fù)情景。(7)根據(jù)研究所得的構(gòu)林坪流域泥石流啟動降水閡值以及2013年構(gòu)林坪泥石流溝災(zāi)害的歷史記錄,得到構(gòu)林坪泥石流溝泥石流啟動的地表徑流深度閾值為9.49mm。(8)基于地表徑流深度閡值,以2013年5月24日發(fā)生泥石流災(zāi)害為基準(zhǔn),模擬了不同生態(tài)修復(fù)情景下構(gòu)林坪泥石流溝的地表徑流深度的變化特征,結(jié)果顯示,本文設(shè)計的9種生態(tài)修復(fù)情景均能夠使地表徑流深度降低到地表徑流深度閡值以下,其中耕地退耕為林地和灌叢的生態(tài)修復(fù)情景降低幅度最大,說明人類可以通過生態(tài)修復(fù)工程遏制泥石流的啟動,降低災(zāi)害發(fā)生的幾率,從而有效地防治泥石流災(zāi)害。
[Abstract]:The white Longjiang basin is one of the regions with high soil erosion and debris flow disasters in China. Ecological restoration is an important means to improve the fragile ecological environment in the white Longjiang River Basin and prevent and control soil erosion and debris flow. The simulation of the restoration effects of different ecological restoration patterns is an important scientific basis for the ecological restoration in this basin. In this paper, the SWAT distributed hydrological model based on physical mechanism and its scenario simulation method are selected. From the angle of the surface ecological hydrological process, the key index of surface runoff depth is selected, and the runoff changes in the white Longjiang basin under different ecological restoration models are simulated and analyzed, and the typical debris flow gully in the white Longjiang basin is further studied. As an example, based on the threshold of surface runoff depth initiated by debris flow, the effects of different ecological restoration methods on the disaster mitigation of debris flow in this basin are analyzed. The main conclusions are as follows: (1) the SWAT model is suitable for the white Longjiang basin. The flow of the flow into the Wudu hydrological station in the middle reaches of the white Longjiang River Basin and the downstream Bi Kou hydrologic station. Line rate determination and verification, efficiency coefficient and correlation coefficient all meet the basic requirements of SWAT simulation, and can objectively and accurately simulate the surface runoff depth and runoff in the white Longjiang basin. (2) through the sensitivity analysis of SWAT model parameters, the parameters of the runoff in the white Longjiang basin are greatly affected, including CN2 (runoff curve coefficient), S URLAG (surface runoff lag coefficient), CH K2 (main channel hydraulic conductivity) and so on. (3) simulation of the ecological restoration effect of debris flow disaster in the white Longjiang basin. This paper designs 35 ecological restoration models based on the national policy of returning farmland to forest and grass, including 5 kinds of extreme patterns (scenarios) and 30 reasonable patterns (4) analysis of 5 extremes The results show that the ecological restoration scenario of returning farmland to the evergreen forest is the most effective for reducing the surface runoff depth of the basin, the decline rate is 12.79%, and the ecological restoration effect is the best. Then the monthly average surface runoff depth changes under the extreme situation are analyzed from the monthly time scale. Compared with the surface runoff depth of the baseline scenario, the surface runoff depth of the extreme scenarios fell throughout the year, and there was no rise in the surface runoff depth in a few months, indicating that the simulation results had higher accuracy. (5) the annual surface runoff depth changes of the white Longjiang basin under the 30 reasonable scenarios were analyzed. The results showed that when the vegetation types were the same after the conversion of ploughing, the slope of cultivated land was lower than 15 degree farmland, and the degree of reducing the depth of surface runoff was lower than that of all the arable land. But it was higher than the situation that the slope was more than 25 degrees. The efficiency of reducing the depth of surface runoff was the highest. Taking the scenario of returning farmland to evergreen forest, an average of 1km2 cultivated land was taken as an example. The depth of surface runoff decreased by 0.0095mm. in the basin. Finally, the situation of different vegetation types at different slope grades was analyzed. The results showed that the surface runoff was the surface runoff when the tillage type was the combination of the evergreen forest and the shrub. The maximum depth decreased. (6) simulation of the ecological restoration effect of debris flow disaster in the construction of Lin Ping basin. Based on the national policy of returning farmland to forest and grass, combined with the distribution law of natural vegetation in the basin, 9 ecological restoration models were designed. In the domain, the effect of cultivated land restoration for forest land was the most obvious, and the annual surface runoff depth decreased by 21.15%, followed by the combination restoration situation of woodland and shrub. (7) according to the study on the starting precipitation of the debris flow in the construction of the forest plateau and the historical records of the debris flow gully in 2013, the debris flow gully of the forest floor was constructed. The depth threshold of surface runoff started by debris flow is 9.49mm. (8) based on the depth of surface runoff. Based on the debris flow disaster in May 24, 2013, the change characteristics of surface runoff depth in the debris flow gully of different ecological restoration scenarios are simulated. The results show that the 9 ecological restoration scenarios designed in this paper can make the surface of the earth surface. The depth of runoff is reduced to below the depth of surface runoff, and the ecological restoration scenario of cultivated land and shrub has been reduced to the greatest extent. It shows that human can control the start of debris flow through ecological restoration project, reduce the probability of disaster and effectively prevent and control the debris flow disaster.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X171.4

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