Yihe River Research Articles

基于GWR模型的伊河流域土壤有机碳空间分布特征及影响因素分析

土壤有机碳作为陆地碳库主体，其分布特征及与驱动因素的空间关系对土壤碳周转过程有重大影响。通过野外调查、采样和室内分析，基于地理加权回归（GWR）模型结合9个环境和土壤变量，建模分析伊河流域土壤有机碳空间分布状况，以及影响其分布的主要因素。研究发现，流域表层土壤有机碳在3.37-38.34 g/kg之间，上、中、下游有机碳分布存在空间差异，其中上游差异最大，下游差异最小。相关分析表明，有机碳与土壤理化性质相关性显著，与年平均气温以外的环境因子相关性不显著。GWR模型较好地预测了伊河流域土壤有机碳空间分布，局部决定系数在0.49-0.64之间，自下游到上游，决定系数逐步升高，对上游的预测精度最高。分析发现，在海拔较高的中上游区域，土壤有机碳含量主要受立地环境、成土母质和地表覆盖的影响；在中上游低山丘陵区，人类活动和环境因素共同影响了土壤有机碳含量；在中下游平原区农业活动和化肥投入是造成土壤有机碳含量较高的主要因素。研究揭示了各因素对有机碳影响的空间分异特征，可为伊河流域土壤生态系统的合理发展和管理提供依据。;Soil organic carbon (SOC), as the main body of land carbon pool, its distribution characteristics and spatial relationship with driving factors have significant impacts on the process of soil carbon turnover. Through field investigation, sampling and indoor analysis, based on the geographical weighted regression (GWR) model combined with nine environmental and soil variables, the spatial distribution of soil organic carbon and its main affecting factors in the Yihe River Basin were analyzed. The results showed that:(1) the distribution of organic carbon in the surface soil was between 3.37-38.34 g/kg. There were spatial differences in the upper, middle, and lower reaches, among which the difference in the upper reaches was the largest and the difference in the lower reaches was the smallest. (2) Soil organic carbon was closely related to the physical and chemical properties of soil itself, and was less affected by environmental factors other than annual average temperature. (3) The GWR model can predict the spatial distribution of soil organic carbon in the Yihe River Basin, and the local determination coefficient was between 0.49-0.64. From the downstream to the upstream, the determination coefficient increased gradually, and the prediction accuracy of the upstream was the highest. (4) In the middle and upper reaches of high altitude, soil organic carbon contents were mainly affected by site environment, soil parent material, and surface coverage. In the middle and upper reaches of low mountains and hills, human activities and environmental factors jointly affected soil organic carbon content. In the middle and lower reaches of plain area, the agricultural activities and chemical fertilizer input were the main factors causing high soil organic carbon content. This study revealed the spatial differentiation characteristics of the effects of various factors on organic carbon, which could provide a basis for the reasonable development and management of soil ecosystem in the Yihe River Basin.

Ecosystem Services Flow and Its Coupling Evaluate of Supply and Demand — A Case Study of Yihe River Basin

Ecosystem services flows (ESF) is an important contributor to the delivery, transformation, utilization, and maintenance of ecosystem services (ES). It provides linkages between the provision of ecosystem services and human demands. The landscape area and dynamic changes in Yihe River Basin were explored through ArcGIS, and the regional ecosystem services value evaluation matrix were also developed through the expert experience, based on which supply rate (SR) and supply-demand ratio (SDR) were constructed. The ecological balance and sustainable development of the Yihe River Basin were discussed based on the potential supply of ecosystem services, and variations in actual human demand at different temporal-spatial scales. The state of ecological balance and sustainable development was also identified based on the spatially explicit model. The result shows: (1) the speed of single land use change dynamics of construction land in the Yihe River Basin was the fastest in the past 30 years. The largest variation of comprehensive land use change dynamics was occurred during 1987 ~ 1995, while the smallest was in 1995 ~ 2005; (2) the minimum and maximum values of the overall ecosystem services SR were 0.500 and 0.916 over the Yihe River Basin in the past 30 years, respectively. There is a noticeable spatial differentiation in the balance of supply and demand in the river basin, the upper reaches were in an ecological surplus area, while the middle and lower reaches were in an ecological deficit; (3) the actual ES delivered by the flows to humans account for a large proportion of potential ES in the Yihe River Basin. However, the services flow and the balance of the ecosystem in the Yihe River Basin were decreased during 1987 ~ 2015. Although the ecological deficit area in the basin was increased significantly, the Yihe River Basin was still in a sustainable state in 2015. The climate regulation service produced by the forest was the most essential contributor to the sustainable development of the Yihe River Basin, including the service of local climate regulation and air quality regulation. The results were expected to provide valuable information for ecosystem management and formulate desired ecological compensation policies.

Spatio-Temporal Variation Characteristics of Water Quality and Its Response to Climate: A Case Study in Yihe River Basin

Spatial-temporal patterns of river water quality, the identification of pollution sources and contaminated areas are crucial to water environment protection and sustainable development of the river basin. In this study, spatial-temporal characteristics of river water quality in the Yihe river basin were investigated through multivariate analysis methods, including principal component analysis (PCA), cluster analysis (CA), discriminant analysis (DA), and one-way ANOVA. The water quality indicators (Hydrogen ion concentration (pH), electric conductivity (EC), dissolved oxygen (DO), turbidity, chemical oxygen demand (COD), total phosphorus (TP), and ammonia nitrogen (NH4+-N)) were investigated at 17 sampling sites in three periods (i.e., high-, mean-, low flow period) during 2016 ~ 2017. The results show that: (1) PCA served to extract and recognize the most significant indicators affecting water quality in the Yihe river basin, i.e., pH, EC, COD, and NH4+-N. (2) CA divided the Yihe river basin into three groups with similar water quality features, namely the upper, middle, and lower reaches. (3) DA demonstrated strong dimensionality reduction ability with the accuracy of clustering was 94.1%, and only a few indicators (i.e., DO, EC, turbidity, NH4+-N, and TP) could reflect the spatial variations in water quality. (4) One-way ANOVA indicated that the water quality was the worst in the lower reach of Yihe river basin during the mean-flow period, followed by which in the upper and middle reaches during the high-flow period. (5) The spatiotemporal characteristics of water quality were mainly restrained by human factors (e.g., the construction of highway and agricultural activities), climate change (e.g., precipitation and temperature), and natural environments (e.g., topography).

Water Sources and Factors Controlling Hydro-chemical Compositions in the Yiluo River Basin

An important tributary in the middle stream of the Yellow River, the Yiluo River consists of the Luohe River and Yihe River, which converge at Yanshi City. Mining activities were widely distributed in the upstream of the Yiluo River Basin (YRB), while residential areas concentrated in the downstream were coupled with extensively industrial and agricultural activities. To illustrate the influences of variable anthropogenic activities on the hydro-chemical composition of river water of the YRB, water samples from the main stream and tributaries were collected in the flood season (August) and normal season (December), respectively. The hydrogen and oxygen isotope values coupled with cation and anion content were analyzed. Temporal and spatial variations of hydrogen and oxygen isotopes and ion content were utilized to elucidate the sources and factors controlling the hydro-chemical composition of the river water, and to illustrate the pathways of human effects. The results demonstrated that:① Average hydrogen and oxygen isotope values (δD and δ18O) of Luo River water were -56‰ and -7.9‰, and -55‰ and -8.1‰ in the flood season and normal season, respectively. Mean δD and δ18O values of Yi River water were -49‰ and -6.9‰, and -53‰ and -7.8‰ in the flood season and normal season, respectively. These temporal variations indicated that river water was mainly recharged by local atmospheric precipitation. ② The dominant water hydro-chemical type was HCO3-SO4-Ca-Mg in the main stream of the YRB, and the ratios of Ca2+ and HCO3- molar equivalent concentrations in the flood season were lower than those in the normal season, while the ratios of SO42- molar equivalent concentrations were higher than those in the normal season, indicating more sulfate dissolved in the river water in the flood season. ③ Carbonic acid and sulfuric acid simultaneously reacted with carbonate and silicate rocks, and in the Luo River more carbonate rocks were weathered, while in the Yi River more silicate rocks were weathered. ④ Human effects on river water were mainly concentrated in the upstream where wastewater input was derived from mining activities, while in the downstream pollution of the river was due to industrial wastewater and sewage input. ⑤ Spatial variations of sulfate sulfur isotope values were mostly due to differences between anthropogenic activities in the upstream and downstream of the Yiluo River. Negative sulfur isotope values in the upstream river water confirmed dissolved sulfate from sulfide mineral oxidation, which also indirectly verified the rock chemical weathering by sulfuric acid in this area. Positive sulfur isotope values in downstream river water were connected with industrial wastewater and sewage.

Quantifying the effects of climate variability, direct and indirect land use change, and human activities on runoff

Much attention has been recently focused on the direct hydrological effects (DHEs, such as runoff yield and concentration) of climate variability and land use/cover change (LUCC); however, the influence of LUCC on regional climate change and corresponding runoff change (indirect hydrological effect, IHE) have rarely been assessed quantitatively. This study employed the Mann-Kendall test and ensemble empirical mode decomposition (EEMD) method to analyze linear and nonlinear trends in potential evapotranspiration (PET), precipitation and runoff and their correlation in typical basin (Yihe River) in eastern China during 1951–2013. This study presents a framework to quantify runoff change in a detection and attribution study based on the Soil and Water Assessment Tool (SWAT) and Weather Research and Forecasting (WRF) model, and it quantifies the effects of climate variability, DHE and IHE of LUCC (1990–2010) and other human activities on runoff. The results indicate that (1) the annual PET in the Yihe River basin had an increasing trend, with a rate of 6.3 mm/decade, while the precipitation and runoff during the period 1951–2013 exhibited decreasing trends, at rates of 26.6 mm/decade (a = 0.05) and 0.16 × 108 m3/decade, respectively. (2) The runoff, PET and precipitation had similar periodic at inter-annual scales (approximately 3 years and 6 years) and inter-decadal scales (approximately 13–16 years). The contribution rate of runoff to total change from the inter-annual scale was the largest, reaching 58%, and those from the inter-decadal scale and multi-decadal scale were 6% and 11%, respectively. (3) The results also revealed that climate variability was likely to be the principle cause of an obvious decrease in runoff, and the contribution rate was as high as 90% before the 1980s while declining to 66.3% in 1990–1999. Furthermore, DHE, IHE and other human activities were responsible for 18.5%, 9.2% and 6.0%, respectively, of the runoff change in the 1990s. It is worth noting that the percentage of downward runoff accounted for 35.8% and 21.3% from DHE and IHE, respectively, during 2000–2013, which implied that human activities have gradually become the dominant factors affecting runoff change, with a contribution of 77.1%.

Analysis of runoff variation characteristics in Yishuhe River Basin

Yishuhe River Basin is located in the northeast of the Yishusi River Basin, with the watershed area of about 18200 km2. It is necessary to analyze the variety characteristics of runoff in Yishuhe River Basin, and it will provide technical support for flood control and drought relief. Based on the past continuous 60 years’ data of runoff measured at 2 hydrometric stations and precipitation at 23 precipitation stations in Yishuhe River Basin, this study analyzed the monthly and annual variation characteristics of the runoff in Yishuhe River Basin using some indexes and methods such as complete regulation coefficient and nonuniformity coefficient, concentration ratio, concentration period, Man-Kendall trend test and mutation detection, and so on. The research results indicate that the distribution of annual runoff in Yishuhe River Basin is uneven, the monthly maximum precipitation occurs in August generally, and the continuous four months’ runoff even accounts for 80% of that of the year. The annual runoff shows a decreasing trend with time at Linyi station in Yihe River and Daguanzhuang station in Shuhe River, and the tendency of runoff reduction is significant in Yihe River with an abrupt point happening in 1966 and 2013.

Analysis and research on the plan of Yihe River rerouting line

The Yihe river channel is from Liujiadoukou to Beijing-Hangzhou Canal. By analyzing the restricting factors of the basic conditions of the resume navigation of the inland river, this paper puts forward three line schemes, and carries on the utilization of river and waterway, the guarantee of the water resources, sluice dam and bridge, artificial canal. It is concluded that line 3 is the optimal rerouting line. The optimal line is obtained: Liujiadaokou Sluice→Sulu Boundary→ Shiba Village→ Huangnihe River→Chenghe River→Beijing-hang Canal. The total length of the waterway is 86.2 km, of which 54.5 km is in Shandong Province and 31.7 km in Jiangsu Province.

The Impacts of Climate Variation and Land Use Changes on Streamflow in the Yihe River, China

Climate variation and land use changes have been widely recognized as two major factors that impact hydrological processes. However, it is difficult to distinguish their contributions to changes in streamflow. Quantifying their contributions to alteration of streamflow is especially important for the sustainable management of water resources. In this study, the changes in streamflow for the period of 1960–2008 at two stations (Dongwan and Luhun) were analyzed in the Yihe watershed in China based on hydrological data series and climate parameters. Using a non-parametric Mann–Kendall (MK) and Pettitt’s test, as well as Budyko analysis, we first examined the trends of hydroclimatic variables and the breakpoint of annual streamflow over the past 50 years. Subsequently, we evaluated the contributions of annual precipitation (P), potential evapotranspiration (PET), and land use condition (represented by w), respectively, to streamflow variation. We observed a decreasing trend for P, as well as increasing trends for PET and w. Annual streamflow showed a significant downward trend with an abrupt change occurring in 1985 during the period of 1960–2008. Accordingly, we divided the studied period into two sub-periods: period I (1960–1985) and period II (1986–2008). The sensitivity of the streamflow to the different environmental factors concerned in this study differed. Streamflow was more sensitive to P than to PET and w. The decrease in P was the greatest contributor to the decline in streamflow, which accounted for 50.01% for Dongwan and 55.36% for Luhun, followed by PET, which accounted for 24.25% for Dongwan and 24.45% for Luhun, and land use change was responsible for 25.25% for Dongwan and 20.19% for Luhun. Although land use change plays a smaller role in streamflow reduction, land use optimization and adjustment still have great significance for future water resource management, since climate variation is difficult to control; however, the pattern optimization of land use can be achieved subjectively.

TUPU characteristics of spatiotemporal variation for land use in the Yihe River Basin

TUPU characteristics of spatiotemporal variation for land use in the Yihe River Basin

Morphological characteristics of the paleochannel of the Yihe River in the Last Glacial Maximum, Shandong Province, China

ABSTRACTThe paleochannel of the Wenhekou–Liudaokou reach of the Yihe River was investigated using electrical soundings along the Zhuyong and Chuanliujie cross sections and drilling at the Chuanliujie cross section. Drilling data from the Liuhang Rubber dam and the Jiefang, Taoran, Yihe, and Luocheng road bridges were also used. Seven stratigraphic cross sections of the Yihe River paleochannel were confirmed based on electrical sounding and drilling, and samples were collected for 14C and optically stimulated luminescence dating near Zhuyang village, Chuanliujie village, Liuhang Rubber dam, south bank of the Benghe River bridge, and the riverbed near the Yihe Road bridge. The dating results suggest that the channels below 76.0, 70.0, 69.5, 55.1, 52.4, 56.5, and 56.4 m near Zhuyang village, Chuanliujie village, Liuhang Rubber dam, Jiefang Road bridge, Taoran Road bridge, Yihe Road bridge, and Luocheng Road bridge are paleochannels of the Yihe River during the Last Glacial Maximum (LGM). Lithology of the riverbed is complex and characterized by fracture zones. This reach of the river was braided with high width–depth ratios and the deep, incised valley at the Jiefang and Taoran road bridges was formed by a regional deep cut during the LGM.

Influence of the island with grass and the island with trees to water quality in Yihe River, China

Influence of the island with grass and the island with trees to water quality in Yihe River, China

Use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the Yimeng Mountain region, China

Information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human-influenced landscapes that have been subjected to recent environmental changes, and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers. The Yimeng Mountain region, characterized by alternating granite and limestone, is one of the most susceptible regions to soil erosion in northern China, and has been subjected to intensive anthropogenic activity in recent years. Soil loss from areas underlain by granite is particularly obvious, and is the main sediment source for the Yihe River. In this study, we used reservoir deposits to estimate the changes in sediment yields over the past ~50years from a small catchment underlain by granite, namely the Jiangzhuang catchment in the Yimeng Mountain region. Three cores were collected from the Jiangzhuang Reservoir in the catchment. The activities of 137Cs and 210Pbex at different depths, clay (grain size <5μm) contents, and sedimentary organic carbon (SOC) contents in the cores were analysed with reference to human activity and environmental change in the catchment. The chronologies of the cores were established by 137Cs and 210Pbex dating. The area-specific sediment yield (SSY) for different time periods since dam construction was estimated from each core by referring to the original capacity curve of the reservoir. The results indicate that the depth profiles of 137Cs, 210Pbex, clay, and SOC contents in cores from the Jiangzhuang Reservoir reflect the general history of human disturbances on the catchment over the past ~50years. The estimated SSY value from each core for each period ranged from 7.2±2.7 to 23.7±8.3tha−1y−1, with a mean of 12.5±4.6tha−1y−1. SSY decreased during 1954–1972, and then showed a general tendency to increase. The temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment.

Hydrological studies of the historical and palaeoflood events on the middle Yihe River, China

Palaeo–hydrological and sedimentary investigations were carried out in the Longmenxia Gorge of the middle Yihe River. Five bedsets of flood slackwater deposits (SWD) were found interbedded into Holocene aeolian loess–soil profiles in the river bank at the Longmenxia site. They were identified as the deposits of the suspended sediment load during the extreme flood events of the Holocene. The minimum flood peak discharges were estimated to be 12, 300–15, 300m3/s using the slope–area method. These are about twice the largest gauged record (7180m3/s) that has occurred since 1937. These flood events occurred at 3100–3000 a B.P., 1800–1700 a B.P., 700–550 a B.P. and 350–250 a B.P., as dated by optically stimulated luminescence (OSL) in combination with stratigraphic correlation, to which may be added the recorded events of the 223 and 1761CE floods. These were associated with Holocene monsoonal shifts and abrupt climatic events. This research not only provides palaeoflood discharge estimates on the middle Yihe River, but also provides important data for understanding interactions between regional hydro–climatic systems and global climate change in humid and semi–humid monsoonal regions, such as China.

Holocene climatic events recorded in palaeoflood slackwater deposits along the middle Yiluohe River valley, middle Yellow River basin, China

Palaeohydrological investigations were carried out in the middle reaches of the Yiluohe River, a major tributary in the lower–middle Yellow River basin. Typical palaeoflood slackwater deposits (SWDs) were identified in the Holocene pedostratigraphy on the cliffy river banks. Analytical results, including magnetic susceptibility and grain-size distribution data, indicated that these SWDs were deposited from the suspended sediment load in flood water. These SWDs are different from eolian loess, soils and aeolian sands in the riverbank profile. They recorded several episodes of extraordinary palaeoflood events. In the Longmenxia reaches of the Yihe River valley, these flood events were dated at 3100–3000a, 1800–1700a, 770–610a, and 420–340a using the optically stimulated luminescence method in combination with the pedostratigraphic correlations. In the Longhutan reaches of the Luohe River valley, the palaeoflood events were dated at 1975–1466a, i.e., from the Han to Wei dynasties (AD 25–534), during which the capital city on the river banks was flooded many times, as recorded in the literature. These extraordinary flood events are well correlated chronologically with the known Holocene climatic events that occurred in the Northern Hemisphere. Thus, the monsoonal climate was highly variable with both floods and droughts occurring frequently during these episodes. These results are important for understanding the response of river systems in eastern Asia to global changes.

Quantitative Estimation of the Impact of Precipitation and Land Surface Change on Hydrological Processes through Statistical Modeling

Precipitation variability and land surface changes are the two primary factors that affect basin hydrology, and thus estimation of their impact is of great importance for sustainable development at a catchment scale. In this study, we investigated the long-term changes in precipitation and runoff, from 1961 to 2011, in the Yihe River basin by Mann-Kendall test. A new method of trend pattern was put forward and used to identify the trends of precipitation and runoff, which indicated that the basin had a decreasing trend in annual runoff. The change point occurred in the year 1985 dividing the long-term series into two periods. Precipitation elasticity and linear regression methods were used to quantify the impact of precipitation and land surface change on runoff and provided consistent results of the percentage change in an annual runoff for the postchange period. Use of these methods reveals that the reduction in annual runoff is mainly due to precipitation variability of 56.38–67.68% and land surface change of 43.62–32.32%, as estimated by precipitation elasticity and linear regression methods, respectively. Due to the rapid growth of urbanization, the land surface change increased from 1990 to 2010. The result of this study can provide a reference for the management of regional water resources.

Distribution and assessment of heavy metals in the surface sediment of Yellow River, China

Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study, fourteen surface sediment samples were taken in the middle reach of the Yellow River. Contents of Zn, Pb, Ni, Cu, Cr, Cd, As were measured, and the pollution status was assessed using three widely used pollution assessment methods, including the single factor index method, Nemerow pollution index method and potential ecological risk index. The concentrations of the studied heavy metals followed the order: Zn>Cr>Cu>Ni>Pb>As>Cd. Nearly 50% of sites had Cu and Cr accumulation. The concentration of Cu at the Yiluo River exceeded the secondary standard value of the Environmental quality standard for soils. Comparison of heavy metal concentrations between this study and other selected rivers indicated that Cu and Cr may be the major pollutants in our case. The single factor index indicated that many samples were at high levels of pollution for Cu and Cd; the Nemerow pollution index indicated that the Yihe River, Luohe River, Yiluo River and Huayuankou were polluted. According to the results of potential ecological risk assessment, Cd in the tributaries of Luo River, Yihe River, and Yiluo River showed high risk toward the ecosystem and human health, Cd in Huanyuankou and Cu in Yiluo River showed a middle level of risk and other samples were at a low level of risk.

Quantifying the Hydrological Response to Water Conservation Measures and Climatic Variability in the Yihe River Basin, China

In this study, variations in the hydrological responses of the Yihe agricultural watershed in the Yihe River Basin in China were analysed based on decadal period data from 1961 to 2011. Precipitation and streamflow data showed a positive trend and evapotranspiration a negative trend. Human activities dominated in the basin for the study period, but the results show inconsistencies between 1989 and 2011. The contribution of human activities and climate variability were quantified through simple linear regression and a physically based modelling approach (hydrological sensitivity). The results suggest that the streamflow of the Dongwan Basin has decreased compared to the baseline period (1961–1968). The contributions of human activities and climate variability were 17% and 83% for 1970–2011 using a simple linear regression approach. The hydrological sensitivity method quantified 119% and −19% of human activities and climate variability respectively for the same period.

OSL and radiocarbon dating of flood deposits and its paleoclimatic and archaeological implications in the Yihe River Basin, East China

Flood is a kind of serious nature disaster, so studies on the palaeofloods are the keys to understand the mechanisms and their relationships with climatic change, geomorphologic evolution and civilization evolution are of great importance. The floods happened frequently in the Yihe-Shuhe River Basin in history, forming the alluvial plain and affecting the evolution of the ancient civilization. However, the complex sediment sources and depositional processes make the flood deposits difficult to be dated and consequently hinder our understanding to the palaeofloods. In this study, we present twelve Optically Stimulated Luminescence (OSL) ages and four AMS 14C ages of flood deposits to study the palaeoflood activities in the Yihe River Basin and its palaeoclimatic and archaeological implications. The youngest OSL age of 0.19 ± 0.02 ka at the depth of 0.5 m shows that the residual OSL age, if any, must be much smaller than this amount, and the well comparison between OSL ages and AMS 14C ages further confirm that the flood deposits could be well bleached before buried and consequently the OSL ages are not overestimated. The source of sediments from ground surface in the mountain regions in the upper stream and the special characteristic of quartz might have contributed to the sufficiently bleaching. Consequently, OSL dating has the potential to offer reliable chronology for the flood deposits. The extraordinary floods happened at 4.1–3.8 ka, 3.3–3.0 ka and 0.9–0.1 ka correspond to the global abrupt climatic events, demonstrating that the extreme floods might be caused by or be parts of these climatic instabilities in monsoonal China. The flood happened at 4.1–3.8 ka might have directly caused the decline of the highly developed late Neolithic civilization (Longshan Culture) in the Yihe-Shuhe River Basin.

Discussion of the Measurement in the Construction of Extra Large Bridge

Yihe River No. 2 extra large bridge is taken as an example in this paper, from the establishment of control network, the pile foundation to the lofting of caps and other structures, this paper introduces the measurement methods used in the extra large bridge construction process, and how to assure the accuracy of bridge construction in the measurement as well, which provides reference for similar projects.