Changes to herbaceous plant communities on a regulated desert river

Riparian plant communities are shaped by gradients of disturbance intensity and frequency and resource availability. Reservoir operation can alter the composition and abundance of riparian vegetation by changing the flood regime and by trapping fine sediments and associated nutrients within the reservoir system. We examined differences in herbaceous species richness, abundance and composition in Populus‐Salix stands along an unregulated and regulated reach of a river in semi‐arid Arizona, contrasted flood inundation frequency and edaphic conditions (soil moisture, nutrients and texture) between the reaches, and interpreted the vegetation differences in light of observed differences in environmental conditions. Flooding frequency was similar between reaches, but the proportion of fine textured soils in the unregulated reach was nearly double that of the regulated reach and soil nutrient levels were up to three times higher in the unregulated reach. Herbaceous cover and richness were consistently lower in the regulated reach, with between‐reach differences greatest during dry seasons. These patterns suggest that an edaphic‐based change in resource availability is the principal pathway by which river damming is altering herbaceous vegetation in this system. Our results demonstrate that sediment transport within riparian corridors is important for maintenance of herbaceous communities and that restoration of flow regimes alone may be insufficient to restore herbaceous flora on some regulated reaches. Copyright © 2008 John Wiley & Sons, Ltd.     

黄河水沙过程调控与塑造下游中水河槽

随着黄河流域来水来沙过程的大幅变化及人类活动的加剧，黄河的健康状况日趋恶化。通过对黄河健康的内涵、维持黄河健康生命的理论与技术支撑、流域水沙资源优化配置数学模型、大型水利枢纽联合运用对黄河下游河道的减淤作用、塑造黄河下游河道中水河槽等方面的研究，提出了对黄河水沙调控体系的认识，并认为在目前实际的黄河水沙条件下，通过小浪底水库的调节，黄河下游河道经过5—8年的努力，是可以塑造出一个平滩流量为4000m^3／s左右的中水河槽的。     

ADCP在长江内河流量比测试验与精度研究

根据长江中下游主要控制河段采用ADCP测流方式，结合长江河流水沙特性、测站特征和水文测船等具体情况，通过野外比测试验，针对ADCP存在的“适宜性”和流量测验精度等问题，进行了较为全面、深入、细致的分析研究．提出了一套能使ADCP适应于长江内河河流特性、现有测船条件的流量测验方法、精度指标等成果，具有广泛的推广应用价值。     

钢的环保型NaCl水溶液缓蚀剂的研制

研制了适用做盐水冷冻液和NaCl冷媒的环保型廉价缓蚀荆,在4℃和30℃的1％～25％ NaCl加自来水的盐水溶液中,研制缓蚀剂对低碳钢、低碳锰钢和Cr-Mo钢都有良好的防锈能力,并且在pH值4.O～8.5的塔里木河水中,该缓蚀剂均有缓蚀效果,而以在中性河水中效果最好。     

太子河流域水资源优化配置供水模型

以追求经济、社会和环境效益的权衡为最优，建立了太子河流域水资源优化配置数学模型，并用多目标递阶动态规划法求解，以取得水资源优化配置的最佳方案．     

Sentinel-1 based Soil Moisture Estimation in Middle Reaches of Heihe River Basin

In this study, a change detection model, constructed using the Sentinel-1 Synthetic Aperture Radar (SAR) data and the simultaneous Normalized Difference Vegetation Index (NDVI) products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat 8 sensors, is applied to estimate soil moisture in middle reaches of the Heihe River Basin, and the effects of two key parameters on retrieval accuracy are comprehensively investigated. The results show that: (1) when constructing the empirical relationship between backscattering coefficient difference ( \mathrm{\Delta } \sigma ) and Vegetation Index (VI) required by change detection model, the optimal sampling ratios in the ( \mathrm{\Delta } \sigma - V I ) space are approximately 2% and 4% for MODIS NDVI and Landsat 8 NDVI, respectively; (2) the Landsat 8 NDVI-based change detection model slightly outperforms the MODIS NDVI-based model in soil moisture retrieval accuracy, with Root Mean Square Error(RMSE) of 0.040 m³/m³ and 0.044 m³/m³respectively; (3) for the key parameters of the change detection method, replacing the ground-based initial soil moisture and scaling factor (maximum soil moisture difference between two adjacent dates \mathrm{\Delta } M s_{max} ) by the low-resolution SMAP/Sentinel-1 L2_SM_SP data will increase the RMSE by 0.01 m³/m³ and 0.04 m³/m³ respectively. Comparing to the parameter of initial soil moisture, the error in soil moisture scaling factor will lead to more significant degradation in the performance of the change detection method, thus it is recommended to use the high precision scaling factor for soil moisture estimation. This study confirms the promising potential of Sentinel-1 data for retrieving high-resolution soil moisture via change detection method and provides practical insight into its application.     

引滦工程黎河下游河道治理技术措施应用

针对引滦工程黎河下游多弯曲型河道采用的治理技术措施进行了初步的应用分析探讨，并通过对黎河下游高陡边坡防护中采用的模袋混凝土技术及软体排技术进行的深入开发应用，探索了黎河下游河道的治理方案．工程经过三年的引滦输水和汛期洪水的考验，实践证明：其技术应用合理，工程实施方便可行，发挥了新技术、新材料的优势，可推广应用到相关河道的治理工程上。     

Seasonal variation in the composition of the drift below a peaking hydroelectric project

We used 0.5 m diameter nets to sample the drift downstream from a peaking hydroelectric project on the Caney Fork River, Tennessee. The relative contribution of the terrestrial, lentic, and lotic environments to stream drift varied seasonally. Stream benthos (primarily Chironomidae and Lirceus fontinalis) occurred in the drift throughout the year; however, their relative importance varied seasonally. Daphnia sp. from the reservoir also occurred in the drift year round with the highest densities in fall and spring when they were the predominant species in the drift. In summer, terrestrial insects apparently utilized exposed portions of the river bed during periods of no power generation. In June as the river stage increased following initiation of generation, adult terrestrial insects became a major component of the drift. Threadfin shad (Dorosoma petenense) dominated the biomass in the drift during December. Although the importance of stream benthos to fish populations is generally recognized, the contribution of the terrestrial and upstream reservoir environments to the forage base in the tailwater may also be important and should be considered in developing management strategies for tailwater fisheries.     

河流系统健康体系及评价方法研究

考虑反映河流系统的动力状况、水质状况、河流地貌和生物指标状况、河流服务状况等4个方面，构建了河流系统健康体系。建立了基于模糊理论的河流健康状况多层次评价模型，给出了相应的评价指标、标准和权重。以海河三岔口河段为例，应用已建的河流系统健康状况模糊综合评价模型，对河流系统的健康状况进行了评价。结果表明，该评价体系能定量地从各层次分项指标和总体角度反映河流健康状况，可为河流管理和生态修复工程提供技术支持。