高温环境下气藏型储气库泥岩盖层密封性评价

为探究高温作用对泥岩盖层密封性的影响,从理论上剖析储气库盖层产生热应力的3种形式,在室内试验的基础上,分析泥岩在高温环境下力学损伤程度和盖层物性封闭评价指标随温度变化特征.结果表明:高温环境下泥岩整体结构性能降低,400℃左右是泥岩在周期热应力作用下损伤的阈值温度;高温作用会显著改变泥岩盖层物性封闭特征,400℃左右是...     

水库淹没区耕地生态服务功能价值估算研究——以黄金坪水电站为例

以黄金坪水电站为例,采用碳税法、造林成本法以及工业氧价格替代法计算气体调节功能价值,并采用其它多种方法计算水土保持价值,以估算水库淹没区耕地生态服务功能价值。通过研究,使水库淹没区耕地总价值构成及量化趋于合理,为进一步完善淹没区耕地补偿构成和补偿标准提供参考。     

Effects of drawdown scenario on retrogressive lateral erosion in a reservoir

The drawdown of reservoirs behind dams is an important management strategy (e.g., for removal of aging infrastructure, flushing of sediment), and an opportunity to study erosional processes. A numerical model was developed to examine retrogressive bank erosion across reservoir drawdown scenarios and to evaluate factors controlling the rate, volume, and mechanisms of lateral erosion. Modeled processes included dynamic drawdown of groundwater, sequential slope failures via limit equilibrium analysis, and retrogression considering stress interaction between failing blocks. Field measurements were coupled with Staged, Slow, and Rapid drawdown scenarios. Results highlight the importance of including retrogression as an avenue for lateral erosion, as sequential block failures were found to occur in all scenarios except Slow drawdown. This result indicates that bank stability models without some means of characterizing the evolution of slope failure during drawdown are likely underestimating bank failure rates and volumes. In contrast, dynamic groundwater was not found to be a dominant control for any drawdown scenario. Model results also demonstrate that the drawdown increment is a first-order control on slope instability via the development of drained or undrained conditions. A majority of failures occurred under undrained conditions. To maximize slope stability, using slow drawdown to activate internal friction under drained conditions is essential. The design of the drawdown rate created a tradeoff between the amount of impact created and when the impact is produced. The study also articulated the need for coupling models and field observations for rapidly changing systems.     

Comparison of Machine Learning Models Performance on Simulating Reservoir Outflow: A Case Study of Two Reservoirs in Illinois,U.S.A.

Reservoir outflow is an important variable for understanding hydrological processes and water resource management. Natural streamflow variation, in addition to the streamflow regulation provided by dams and reservoirs, can make streamflow difficult to understand and predict. This makes them a challenge to accurately simulate hydrologic processes at a daily scale. In this study, three Machine Learning (ML) algorithms, Random Forest (RF), Support Vector Machine (SVM), and Artificial Neural Network (ANN), were examined and compared to model reservoir outflow. Past, current, and future hydrologic and meteorological data were used as model inputs, and the outflow of next day was used as prediction. Simulation results demonstrated that all three models can reasonably simulate reservoir outflow. For Carlyle Lake, the coefficient of determination and Nash–Sutcliffe efficiency were each close to one for the three models. The coefficient of determination, relative mean bias, and root mean square error indicated that the SVM performed better than the RF and ANN, but the SVM output displayed a larger relative mean bias than that from RF and ANN. For Lake Shelbyville, the ANN model performed better than RF and SVM when considering the coefficient of determination, Nash–Sutcliffe efficiency, relative mean bias, and root mean square error. The study results demonstrate that the three ML algorithms (RF, SVM, and ANN) are all promising tools for simulating reservoir outflow. Both the accuracy and efficacy of the three ML algorithms are considered to support practitioners in planning reservoir management.     

丹江口水库蓄水后汉江中下游水文时空变化的#br# 定量评估及其生态影响

采用变化范围法（RVA）定量研究了丹江口水库蓄水后汉江中下游水文情势的时空变化,评估出汉江干流变化度最大的江段和水文特征指标类别,分析了其对应的生态影响,并针对汉江流域的四大家鱼和水华问题进行了敏感水文指标的变化度分析。结果显示:丹江口大坝蓄水后,汉江下游河道流量是中变化度占主导,比例范围为47～63%;水位是高变化度占主导,襄阳站和皇庄站高变化度的水文指标所占比例远大于其它站点,依次为53% 和75%,各站水位较蓄水前下降了1～2 m。黄家港站高/低流量脉冲出现的频率减少（变化度为-0.49和 -0.62）,且持续的时间变短（变化度为-0.87和 -0.74）。皇庄站和襄阳站流量和水位的月均值和极值较蓄水前减少,逆转次数在高RVA范围内较蓄水前增加（变化度为1.82）。四大家鱼产卵的敏感水文指标出现频率较蓄水前减少,且为中高变化度。下游河道枯水期流量和水位减小,增加了水华发生几率。     

承德市隆化县茅荆坝地热资源的开发利用

承德市隆化县茅荆坝地热资源丰富,受断裂构造控制,属隐伏基岩裂隙、松散岩孔隙型热储,水温最高可达90℃,地温可达30～40℃,水量充足,水中含有多种医用保健化学成分,但在开发利用中存在着项目单一、利用率不高、资源浪费等问题。地热综合利用和地热梯级利用的开发利用模式,即多目的利用、按不同温度逐级利用,加强科学管理,采取限量打井,限制开采。     

Relationship between antibiotic residues and occurrence of resistant bacteria in Nile tilapia (Oreochromisniloticus) cultured in cage-farm

The aim of this study was to investigate the relationship between antibiotic residues found in the muscle of cage-farm-raised Nile tilapia (Oreochromisniloticus), the occurrence of resistant bacteria, and the sanitary practices adopted by farmers in Ilha Solteira reservoir, Brazil. Nine fish (three small fish, 40–200 g; three medium-sized fish, 200–500 g; and three large fish, 500–800 g) were collected from four cage farms every three months from April 2013 to January 2014. Ten antibiotic residues were determined using liquid chromatography-mass spectrometry, and bacteria were isolated and tested for antibiotic resistance to determine the multiple antibiotic resistance (MAR) index. Only three antibiotics (oxytetracycline, tetracycline, and florfenicol) were detected in the muscle of Nile tilapia, and their residues were the highest in small fish; however, the MAR index was higher in large fish. In addition, a direct positive relationship between the MAR index and the concentration of antibiotic residues in Nile tilapia was found. Overall, the adoption of prophylactic management practices improved the sanitary status of cage farms, reducing bacterial infections and hampering the development of antibiotic-resistant bacteria.     

水库移民安置区土地补偿现状与补偿原理

随着农村土地制度的变化,安置区土地补偿问题对于协调水库移民安置中各相关主体之间的利益平衡具有重要的意义。本文基于实地调查,首先分析了水库移民安置区土地补偿的现状和存在的问题;其次,运用土地产权理论和福利经济理论,从安置区土地补偿的原因、范围和补偿原则等方面阐明了安置区土地补偿的基本原理;最后,在此基础上提出了完善相关法律法规、协调水利水电工程建设中利益相关者的关系和利益平衡、体现农地价值等政策建议。结果表明:其一,安置区的土地补偿,无论从现行法律、还是从实际获得的补偿来看,均未体现对安置区土地权益的保护;其二,安置区集体和居民理应获得相应的权益补偿,其补偿范围既包括转出土地使用权的补偿,也包括对共同拥有土地所有权带来的权益分配变化的补偿;其三,土地制度的建设和改进上,应依据安置区土地资源状况和调出土地的状况确定补偿标准,淹没区集体、移民和安置区集体、居民应获得同等补偿,并力求体现农地价值。     

Reservoir Operation with Feedback in a Coupled Land Surface and Hydrologic Model: A Case Study of the Huai River Basin,China

Regarding emerging large‐scale reservoir operation models, reports of reservoir operation feedback for hydrologic modeling are rare, and little attention has been paid to flood control. An operation scheme considering multilevel flood control (MLFC) was first proposed in this study, but more reservoir information was needed. Thus, an alternative scheme was proposed that consisted of a modified version of the reservoir operation scheme in the Soil and Water Assessment Tool Model (MSWAT scheme). These schemes were coupled to a land surface and hydrologic model system with feedback, i.e., a system in which reservoir operation can affect the subsequent simulation, and were investigated in the Huai River Basin. The results show reservoir storage and peak flow were generally overestimated by the original SWAT reservoir scheme (SWAT scheme). Compared with the SWAT scheme, the MSWAT scheme successfully reduced the simulated storage and peak flow at the reservoir stations. For the downstream stations, the streamflow simulations were improved at a significance level of 5%. The performances of the MSWAT and MLFC schemes at the reservoir stations were nearly equivalent. Importantly, reservoir operation feedback to hydrologic modeling was necessary because the reservoir operation effects could not be transferred downstream without it. The streamflow simulation of a reservoir station located on a flat plain was less sensitive to feedback than that of a mountain reservoir station.     

潘口水电站移民安置区土地流转补偿标准研究

兴修大中型水利水电工程不可避免地要征收大量农田,造成大量移民非自愿性搬迁.我国实行开发性移民的方针,强调农村移民主要采取农业安置的策略.然而,移民的迁入势必会对安置区居民的土地权益带来负面的影响.因此,根据"卡尔多-希克斯"社会福利改进标准,要实现安置区土地向移民转移过程的社会福利改进,需要对利益受损的安置区集体和居民给予相应的补偿以弥补其福利损失.本文以湖北省竹山县潘口水电站为例,在对竹山县溢水镇、宝丰镇两个乡(镇)5个移民安置点的73户安置区居民进行问卷调查的基础上,运用条件价值法(CVM)对安置区土地流转的补偿标准进行了实证研究,研究结果表明:潘口水电站移民安置区土地流转补偿执行标准均未达到农地实际价值的一半,水田的补偿程度为49.54%.旱地的补偿程度为为44.54%,安置区集体和居民没有获得充分的补偿,因此,需要提高安置区土地流转补偿标准,使安置区居民也能和移民一样地分享到水利水电工程带来的增值收益.