Evaluation of the Impacts of Climate Change on Runoff in Dadu River Basin Based on CORDEX Regional Climate Model

Owing to the rich water resources, the Dadu River basin is an important hydroelectric resources development area in Sichuan Province over China. The climate change will have a great impact on the runoff change in the Dadu River Basin. The prediction of the future runoff in the Dadu River Basin can effectively improve the utilization rate of water resources, and provide a reference for hydropower dispatching. At first, to reduce the uncertainties from climate model, this paper used Stepwise Clustering Analysis to calibrate and validate the CORDEX regional climate model ensemble data from 1970 to 2005 and projected the climate change trend of Dadu River basin from 2035 to 2065. Then the Dadu River watershed scales of SWAT model was established, using the SWAT-CUP for calibration and verification. Finally, the corrected future climate data are used to drive the SWAT model to realize the future runoff forecast in the Dadu River Basin. The results show that under the scenario of RCP4.5 and RCP8.5, the variation range of rainfall is small, and the maximum and minimum temperatures show an overall increasing trend. The maximum (minimum) temperature will increase about 0.6℃ (1.0℃) under the scenarios of RCP4.5 and 0.9℃ (1.4℃) under the scenario of RCP8.5. Compared with the baseline period, the future (2035-2065) annual runoff under RCP4.5 and RCP8.5 scenarios will increase by about 8.6% and 8.2%, respectively. Under the future climate change, the inter-annual runoff in the Dadu River Basin will change greatly, and the trend of runoff fluctuation is not consistent before and after 2050. Before 2050, runoff changes are small, however, after 2050, runoff changes under the two scenarios will increase by about 12%. On the one hand, this trend may be due to the impact of iceberg melting on runoff caused by temperature changes around 2050, on the other hand, it may be due to the combined effect of local plant evapotranspiration and ecological regulation.

A study on the evolution mechanism of agricultural landscape pattern of Dadu River Valley in Danba Region

Taking the Dadu River Basin in the Danba area of Ganzi Prefecture, Sichuan Province as the research area, based on the 2013 and 2016 Landsat8 remote sensing images, the temperature vegetation drought index (TVDI) method is used to divide the Dadu River dry valley into 6 arid gradient regions. Using ArcGIS10.5 software and Fragstats4.2 software to calculate the landscape pattern index of different arid gradient areas in different years, combined with the survey results of agricultural policies, development models, and agricultural landscape patterns in key regions, analyze the evolution of agricultural landscape patterns under different drought gradients. The results show that, except for other forestlands, the degree of landscape fragmentation is decreasing year by year on the gradient of light and moderate drought, and the degree of spatial heterogeneity is higher. On the gradient of extreme drought, the degree of landscape fragmentation is higher, and the degree of spatial heterogeneity is lower.

A contribution to the knowledge of cavernicolous ground beetles from Sichuan Province, southwestern China (Coleoptera, Carabidae, Trechini, Platynini)

Two new genera and four new species of cave-adapted ground beetles are described from Sichuan Province, southwestern China. Uenoaphaenopsgen. nov. is established to place the trechine species Qianotrechus fani Uéno, 2003 occurring in the limestone cave Hua’er Dong, southeastern Sichuan (Luzhou: Gulin). Chu pheggomisetoidesgen. nov. & sp. nov., from the limestone cave Hanwang Dong, northeastern Sichuan (Guangyuan: Chaotian), is somewhat like the European cavernicolous trechine genus Pheggomisetes Knirsch, 1923, from Bulgaria and Serbia, in particular in the configurations of head and pronotum. Boreaphaenops liyuanisp. nov., also from Hanwang Dong, is the second representative of the genus and the first record in Sichuan. Agonotrechus sinotroglophilus Deuve, 1999, a troglophile, is reported from Sichuan for the first time. The other two new species belong to the platynine genus Jujiroa Uéno, 1952: J. uenoisp. nov. from the cave Banche Dong on the northern side of the Dadu River (Leshan: Shawan) and J. wangzhenisp. nov. from the cave Hua’er Dong, which is sympatric with Uenoaphaenops fani (Uéno, 2003) comb. nov. A distribution map for the localities of all abovementioned caves and a key to Jujiroa species known in Sichuan are provided.

Exploration and practice of intelligent engineering in Dadu River hydropower construction

In view of the difficulties in promoting intelligent management in the field of engineering construction, based on the concept of intelligent enterprise and the actual situation of hydropower project-construction management, this paper puts forward the basic concept, main features and general idea of intelligent engineering. Based on a review of the exploration, pilot construction and comprehensive practice of intelligent engineering in the hydropower construction of Dadu River, the practical results of the intelligent engineering of Dagangshan, Houziyan, Shaping-II and Shuangjiangkou hydropower stations are summarized. The technical system and management model of engineering an early-warning decision centre, intelligent dam project, intelligent underground project, intelligent electromechanical project, intelligent security control, intelligent service guarantee, intelligent environmental and water protection, and intelligent resource control in Shuangjiangkou hydropower station are introduced. It is proposed that intelligent engineering is a high integration of information technology, industrial technology and management technology. And it is pointed out that intelligent engineering will lead in the new development of water conservancy and the hydropower industry, and even the engineering-construction field, throughout the world.

Comparison of Detrital Zircon U-Pb and Muscovite 40Ar/39Ar Ages in the Yangtze Sediment: Implications for Provenance Studies

Detrital zircon U-Pb and muscovite 40Ar/39Ar dating are useful tools for investigating sediment provenance and regional tectonic histories. However, the two types of data from same sample do not necessarily give consistent results. Here, we compare published detrital muscovite 40Ar/39Ar and zircon U-Pb ages of modern sands from the Yangtze River to reveal potential factors controlling differences in their provenance age signals. Detrital muscovite 40Ar/39Ar ages of the major tributaries and main trunk suggest that the Dadu River is a dominant sediment contributor to the lower Yangtze. However, detrital zircon data suggest that the Yalong, Dadu, and Min rivers are the most important sediment suppliers. This difference could be caused by combined effects of lower reaches dilution, laser spot location on zircons and difference in closure temperature and durability between muscovite and zircon. The bias caused by sediment laser spot targeting a core or rim of zircon and zircon reworking should be considered in provenance studies.