【作者】 庞敏；

【导师】 李怀恩；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2010， 博士

【摘要】 黄土高原是世界上水土流失最严重的地区之一,生态环境非常脆弱,是黄河泥沙来源的主要区域,恢复该区植被生态并促进可持续发展,减轻黄河下游泥沙水患灾害,已成为该地区亟待解决的首要问题。恢复与建设黄土高原植被,对于改善区域生态环境、振兴区域经济和实现经济社会可持续发展都具有重要意义。本文以黄土高原为背景,以延安城区周围区域以及黄土高原砒砂岩典型地区内蒙古准格尔旗西召沟流域东一支沟等为典型研究区域,采取定位观测与野外调查及室内试验分析相结合的方法,对黄土高原几种植被类型的土壤水分特征、沙棘柔性坝的土壤水库调节效应、沙棘柔性坝的生态水文效应等进行了分析讨论；对植被过滤带对非点源污染物的净化效果进行了试验研究；对沙棘柔性坝的三种流速测量方法进行了优劣比较、对沙棘柔性坝的设计参数进行了分析与讨论；最后,根据环境经济学的有关理论与方法,结合陕西省彬县黄土高原水土保持世界银行贷款二期项目,对小流域水土保持项目的生态效益进行了定量计算,并评价了生态效益在国民经济评价中的贡献。论文取得的主要研究成果与进展如下：(1)自然植被由低级阶段向高级阶段演替过程中土壤水分逐步降低,在退耕初期和草本群落(茵陈蒿群落和草本群落),土壤含水量差异不大,处于较高水平,到了演替的中期,即灌丛阶段,土壤水分有了明显的变化,在灌丛的初期(杠柳灌丛)土壤含水量仍然较高,但是到了灌丛后期(胡榛子灌丛)则土壤含水量已经接近或达到了乔木林的水平。植被由低级阶段向高级阶段演替过程是“土壤水库”的耗水过程。(2)沙棘柔性坝经过淤积可形成深度较厚的沟道土壤水库,沙棘柔性坝土壤水库对砒砂岩沟道土壤水分的调节有着巨大的潜力,可为当地植被的生长与恢复改善供水条件。(3)植被生长调查结果显示：①植被过滤带对地表径流的延滞效应及过滤效果与草本群落的发育状况有密切关系,沙棘不宜作为植被过滤带的主要物种与草本植被混种；②沙棘是一种优良的水土保持植物且在陕西地区长势良好,宜将其种植在草地过滤带和受纳水体之间,可达到稳固河岸和进一步增加地表径流入渗的目的。(4)径流小区模拟试验结果表明：植被过滤带主要通过物理作用并能有效过滤地表径流中的悬浮固体、氮磷营养物质和COD等四种污染物,对四种污染负荷的平均削减率达到了70%以上；植被的密度、高度和刚度对过滤带的净化效果影响显著,草本群落发达的草地过滤带具有较好的过滤效果。(5)应用PIV法、浮标法和染色剂示踪法三种测速方法分别测量了沙棘“柔性坝”内水流的流速,在实验的基础上进行了理论分析和对比。染色剂示踪法的实验结果与PIV法相近,浮标法由于人为因素影响其结果与PIV法相差较大,显得更为粗糙一些;在实验的准确性、可操作性和效果等方面,PIV法要比染色剂示踪法及浮标法更具有实用性。(6)小流域内沙棘“柔性坝”的布设受降雨、下垫面条件、地形等自然条件的影响较大,本文从工程水文学的基本理论出发,提出了从流域设计暴雨洪水及沟道形状共同确定沙棘“柔性坝”种植参数的概化设计思路,并从理论上对沙棘柔性坝的种植参数进行了讨论。(7)运用环境经济学的理论与方法,采用影子价格等方法对植被保持和改良土壤、涵养水源、固碳供氧及维持景观效益等进行定量分析计算,在此基础上,把生态效益纳入到水土保持项目的国民经济评价中,科学地评价了水土保持工程建设成果和投资效益,得出水土保持措施具有显著的生态效益。更多还原

【Abstract】 Loess plateau is one of the most severe zones of soil and water loss in the world, and its eco-environment is very weak, and it is the main sediment source area into the Yellow river. So, the main problem to the Loess plateau is the recovery of its vegetation ecology, the promotion of the sustainable development, and the decrease of the water and sediment disasters in the lower Yellow river. The recovery and building of the plant in the Loess plateau has an important and valuable sense for improving area eco-environment, promoting area economy and realizing the sustainable development of economy and society.In this paper, the Loess plateau is as the background, based on the typical study areas including Yan’an city’s entourage and the east-one gully branched as the xi-zhao gully in the zhun-ge-er county, Inner Mongolia, one of the typical soft rock regions in the Loess plateau, the soil moisture property of the main plant type in the Loess plateau, the adjustment effects of the sea-buckthorn flexible dam on soil reservoir, and the sea-buckthorn flexible dam’s eco-hydrology effects were analyzed by the method of combine of locating observation and field survey and indoor test analysis. Next, the purification effects of the vegetation fitter strip on non-point source pollutions were studied by the test. The merits and shortcomings of the three measuring water flow velocity through the sea-buckthorn flexible dam were compared, and the design parameters of the sea-buckthorn flexible dam were analyzed and discussed. Finally, the ecology benefits of small valley soil and water conservation projects were quantitatively calculated, and the contribution of ecology benefits to national economic evaluation was evaluated by the concerned theory and method of environment-economy subject and combining the two-stage world bank loan on Loess plateau soil and water conservation in bin county in shaanxi province. Achieved main study results and advances in this paper are as follows:(1) The soil water was gradually reduced in the succession course of the national plant from low stage to high stage, the soil water difference was not high and was at a high level at first returning farmland and herb community (Artemisia capillaries thumb and herb community) stage. In the middle succession stage, namely boscage stage, the soil water had an obvious variation, and the soil water was yet at a high level at first boscage stage, but the soil water had approached or attained it of arbor forest in the last boscage stage(corylus bosk). The plant succession course of from low stage to high stage was the consuming soil water stage of soil reservoir.(2) The sea-buckthorn flexible dam could formed deeper gully soil reservoir through alluvium, and the soil reservoir formed by the sea-buckthorn flexible dam had a big adjustment potential to gully soil water in the soft rock region, and that could provide and improve supply water condition for local plant grow and recovery.(3) Plant growth survey results showed that:①the retarding and filtering effects of the VFS to surface runoff were closely concerned about the growth of herb community; and the sea-buckthorn was not fit as main species of VFS and it and herb community could not jointly be plant.②the sea-buckthorn is a kind of excellent plant for soil and water conservation and its growth is very good in shaanxi province, and it was suitably plant in the area between herb VFS and water body for receiving sewage, this can help stable riverbank and further improve the runoff filtering performance.(4) Small district runoff simulation test results showed that:the VFS could effectively filter the SS(suspended solid), N(nitrogen), P(phosphor), and COD in runoff, and the average reducing rate of it to the four kinds pollution load was over 70%; the density, height and rigidity of plant had a marked effect for the purity performance of VFS, and grass filter strip formed by developed herb community had a better filtering effect.(5) By the three methods of PIV technique, buoy and dyed-tracer, water flow velocity in the sea-buckthorn flexible dam was respectively measured, and test data were theoretical analyzed and compared based on test results. The test results observed by dyed-traced was close to that observed by PIV, test results observed by buoy were different from that observed by PIV, and the buoy method was rougher result for man-made factors. PIV technique was more practical than dyed-tracer and buoy techniques in test veracity, practices arid effects.(6) In small watershed, the sea-buckthorn flexible dam’s design was subject to rainfall, underlying surface, terrain and natural conditions etc. The primary design idea was suggested that the sea-buckthorn flexible dam plant parameters were make from watershed design rainstorm and flood together with gully form, and the plant parameters of sea-buckthorn flexible dam were valuably discussed from theory based on the basic theory of project hydrology.(7) Employed environment-economy theory and methods, by the shadow price method, it was quantitatively calculated and analyzed for vegetation conserving and improving soil and water, fixing carbon and supplying oxygen and maintaining landscaping effect. On the basis, ecology benefit was brought into national economic evaluation of soil and water conservation projects. The construction productions and invest benefits of soil and water conservation projects were evaluated and it was obtained that soil and water conservation had very significant ecological benefits.更多还原