跑铅征战流水河

流水河是孝感市的一条内河，也是市区附近水量最大的河流。由于免费垂钓，再加上离市区不足4公里，每天河边的钓者都有20～30人。但多数人只能钓到几条200克左右的小鲤鱼，少数人能有2．5～3．0千克的收获。最近三年我一直不敢去流水河施钓，因为这条河水流得很急，拉饵、打浮等招数都不管用，就连搓大饵钓底，浮标照样被流水冲得歪歪斜斜。如果遇到上游放水，浮标干脆被冲得看不到影，只能靠竿梢和露出水面的主线来判断鱼讯。

教学相长成就高效地理课堂——复习课《河流水的补给》教学反思

2017年修订版《普通高中地理课程标准》提出了地理核心素养,更新了地理课程基本理念,并强调通过学生地理核心素养的培养,落实"立德树人"根本任务的要求。显然,地理新课标更注重学生个体地理品格和综合能力的发展,而不同层次的学生达到的核心素养水平等级有别,对同一地理问题的认知水平和思考的广度及深度存在差异,教师在因材施教的同时,也会收到不同程度的"刺激"。这些刺激点对教师后续教学内容、难度、方法等起到至关重要的作用,进而促使教师在不断反思过程中成长。

Influence of Vegetation Coverage on Surface Runoff and Soil Moisture in Rainy Season in Dry-hot Valley

[Objective]The research aimed to study the effects of vegetation coverage on the changes of soil moisture in rainy season in dry-hot valley.[Method]The surface runoff and soil moisture of slope with vegetation coverage and bare land in rainy reason in Jinsha River at Yuanmou County of Yunnan Province were observed continuously.Moreover,the statistical analysis was made based on the observation data.[Result]The vegetation coverage could decrease surface runoff and the surface runoff on bare land（CK） was 22 times as the plot with vegetation coverage.The soil water content in 0-180 cm layer with vegetation coverage increased by 37.8% than bare land.The stability of soil moisture content in deep layer was enhanced and the physical properties stability of soil was maintained.The soil moisture content in different depth of soil had significant difference and the changes of soil moisture content were obviously different.[Conclusion]The vegetation coverage of slope could change the soil hydrology obviously and keep soil moisture at the higher level,especially at soil layer below 20 cm.

Hydrological Process Factors Analysis of Heihe River Mountain Basin Based on GIS

Hydrological process factors are a reflection of the physical mechanism of basin hydrology,which can provide important basis for the use and protection of water resources.Taking Heihe River Mountain Basin as the study area,the hydrological simulation was made based on SWAT-GIS integrated model platform.The calculation methods of hydrological process factors using SWAT model were described based on the simulation results of runoff from 1990 to 2000.Hydrological process factors in the study area were analyzed by using GIS technology.The spatial and temporal characteristics of precipitation,runoff,infiltration,evapotranspiration and snowmelt in the basin were calculated and analyzed.

Effects of water stress on Haloxylon ammodendron seedlings in the desert region of Heihe inland river watershed, Gansu Province, China

The water relation and leaf gas exchange of saxoul (Haloxylon Ammodendron Bge, a C4 shrub) seedlings were studied under water stress in 2001. Saxoul seedlings maintained high transpiration when the soil moisture was above 11%. The seedlings were able to take up water from soil with above 6 % soil water content, which was the threshold level of soil moisture for seedlings. The relationship between transpiration and potential evaporation was linear for well-watered seedlings. The de-crease of soil water availability led to different degrees of down-regulation of stomatal conductance, leaf transpiration and net CO2 assimilation rate. The stomata played a relatively small part in determining the net CO2 assimilation rate for the same seedling. The relationship between net CO2 assimilation rate and transpiration was linear diurnally, and reduction scale of leaf transpiration was much bigger than that of net CO2 assimilation rate by waters tress treatments, therefore intrinsic wa-ter-use-efficiency increased. High evaporative demand increased the leaf transpiration but inhibited net CO2 assimilation rate. Because of the effect of VPD on transpiration in this region, the transpiration of well-watered and mild water stress seedlings becomes responsive to change in stomatal conductance over a wider range.

Research on Drainage Network Extraction in Liaohe Basin Based on SRTM DEM and ASTER GDEM

In this study,SRTM DEM data and ASTER GDEM data were used as the basic topographic data,and Arc Hydro Tools was utilized for extension module so as to study on extracting digital drainage network of watershed based on surface runoff model,as well as to compare the two extracted results.The result showed that through the introduction of drainage density parameter to determine the river drainage area threshold,the both extracted drainages showed the goodness-of-fit with the factual drainage network on 1∶250 000 scale topographic map,and the extracted digital river could be used in practical operation of the risk assessment model of mountain torrents disaster in Liaohe basin.

Effect of Typical Vegetation Restoration Pattern on Soil and Water Conservation in Yuanmou Dry-hot Valley of Yunnan Province

In Yuanmou dry-hot valley of Yunnan Province,three typical vegetation restoration patterns including production forest transformed from sloping fields to terracing,ecological afforestation within the gully and ecological aforestation in gully head and slope were selected to compare their effects on soil and water conservation.Soil and water loss,soil infiltration rate and the soil moisture dynamics of soil profile with the depth of 0-100 cm of these three patterns and their controls were observed by established standard observation plots in rainy season.The results showed that the soil and water loss of ecological afforestation and production forest terrace reduced by over 30% and 60% compared with their controls（without growth of any vegetation）respectively,showing significant control effect on the soil and water loss.Vegetation restoration also apparently increased the infiltration rate of soil（increased by 100%-200%）.In rainy season,the soil moisture content of ecological afforestation and production forest terrace increased by over 30% and 100% compared with their controls.This indicated that vegetation restoration will not lead to soil aridity during the rainy season;vegetation restoration not only reduced the loss of surface water and soil fine particles,but also enhanced the infiltration of precipitation.These two effects made the soil moisture content increase throughout the profile.

Concentration variations of several ions in stream after a wildfire

In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing＇an Mountains, China. The concentration changes of eight ions （K^＋, Na^＋, Ca^2＋, Mg^2＋, Cl^-, Br^-, NO3^- and SO4^2-） were measured in burned and tmbumed streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca^2＋, whose average concentration was 5.50 mg·L^-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca^2＋〉SO4^2- 〉Na^＋〉Mg^2＋〉NO3^- . The average concentrations of Ca^2＋, SO4^2- , Na^＋＇Mg^2＋,NO3^- showed an increase trend, but those of K^＋, Cl^- , Br had a decreased trend. SO4^2- had the largest loss among these anions, followed by NO3^-. Overall, the increase degree of cation was greater than that of anion after burning.

Nitrate Nitrogen Content Characteristics in Groundwater of Typical Planting Areas in Liao River Basin

The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the NO-3-N content from exceeding standard. The results showed that difference of the contents of NO-3-N in groundwater from different typical planting areas was significant. The highest content of NO-3-N in underground water was 37.4 mg/L from flower-growing region, then 22. 3 mg/L from maize-growing region, 21.9 mg/L from vegetable-growing region, and the lowest content of NO-3-N in underground water was 19.2 mg/L from rice-growing region. Except rice-growing region, the contents of NO-3-N in underground water of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12.5%-87.5%, 9.4%-75.5%, 17.9%-58.9% and 21.4%-96.0% of the samples were exceeding standard limit in maize growing region, rice-growing region, vegetable-growing region and flower-growing region. The contents of NO-3-N in under-groundwater before the rainy season was higher than that of NO-3-N in under-groundwater after the rainy season at the same depth of the well.

Performance of Subsurface Constructed Wetland in River Rehabilitation

[ Objective] This study was to research the treatment effect of different media in undercurrent wetland on contamination, so as to pro- vide reference for rehabitating water body of river along small towns. [ Method ] Three different media of gravel, cobblestone and shale were used to rehabilitate water quality of contaminated river. [ Result ] Gravel, cobblestone and shale all performed well in removing TN, TP and CODw,, in contaminated water, of which gravel stuffed undercurrent wetland run best, averagely removing 49.4% TN, 34.7% and 48. 5% COD~, respectively. [ Conclusion] Undercurrent constructed wetland can effectively improve the water quality of contaminated river, and it is cheaper in cost and simpler in operation, thus suitable for generalizing in small towns of China.

Streamflow response to shrinking glaciers under changing climate in the Lidder Valley,Kashmir Himalayas

The study investigated the streamflow response to the shrinking cryosphere under changing climate in the Lidder valley, Upper Indus Basin(UIB), Kashmir Himalayas. We used a combination of multitemporal satellite data and topographic maps to evaluate the changes in area, length and volume of the glaciers from 1962 to 2013. A total of 37 glaciers from the Lidder valley, with an area of 39.76 km^2 in 1962 were selected for research in this study. It was observed that the glaciers in the valley have lost ~28.89 ±0.1% of the area and ~19.65 ±0.069% of the volume during the last 51 years, with variable interdecadal recession rates. Geomorphic and climatic influences on the shrinking glacier resources were studied. 30-years temperature records(1980-2010) in the study area showed a significant increasing trend in all the seasons. However, the total annual precipitation during the same period showed a nonsignificant decreasing trend except during the late summer months(July, August and September), when the increasing trend is significant. The depletion of glaciers has led to the significant depletion of the streamflows under the changing climate in the valley. Summer streamflows(1971-2012) have increased significantly till mid-nineties but decreased significantly thereafter, suggesting that the tipping point of streamflow peak, due to the enhanced glacier-melt contribution under increasing global temperatures, may have been already reached in the basin. The observed glacier recession and climate change patterns, if continued in future, would further deplete the streamflows with serious implications on water supplies for different uses in the region.

Climate Change and Its Effects on Runoff of Kaidu River, Xinjiang, China:A Multiple Time-scale Analysis

This paper applied an integrated method combining grey relation analysis, wavelet analysis and statistical analysis to study climate change and its effects on runoff of the Kaidu River at multi-time scales. Major findings are as follows: 1) Climatic factors were ranked in the order of importance to annual runoff as average annual temperature, average temperature in autumn, average temperature in winter, annual precipitation, precipitation in flood season, average temperature in summer, and average temperature in spring. The average annual temperature and annual precipi- tation were selected as the two representative factors that impact the annual runoff. 2) From the 32-year time scale, the annual runoff and the average annual temperature presented a significantly rising trend, whereas the annual precipita- tion showed little increase over the period of 1957-2002. By changing the time scale from 32-year to 4-year, we ob- served nonlinear trends with increasingly obvious oscillations for annual runoff, average annual temperature, and annual precipitation. 3) The changes of the runoff and the regional climate are closely related, indicating that the runoff change is the result of the regional climate changes. With time scales ranging from 32-year, 16-year, 8-year and to 4-year, there are highly significant linear correlations between the annual runoff and the average annual temperature and the annual precipitation.

Interannual and Interdecadal Variability of Atmospheric Water Vapor Transport in the Haihe River Basin

The seasonal mean atmospheric precipitable water and water vapor transport over the Haihe River Basin （HRB） in North China with a focus on their interannual to interdecadal variability, and then the relationships of the interannual and interdecadal variability of the water cycle over the HRB to the Pacific Decadal Oscillation （PDO） and E1 Nino-Southern Oscillation （ENSO） phenomena were investigated using the observational and National Centers for Environmental Prediction （NCEP） reanalysis data. There was a strong interdecadal variability for the water cycle （such as precipitation and water vapor transport） over the region, with an abrupt change occurring mostly in the mid 1970s. The intensity of the East Asian summer monsoon largely affected the atmospheric water vapor transport. Generally, the net meridional convergence of the water vapor flux over the region was relatively large before 1965, and it declined gradually from then on with a further notable decrease since mid 1970s. Zonal water vapor transport was similar to meridional, but with a much smaller magnitude and no noteworthy turning in the mid 1970s. Results also suggested that the wind field played an important role in the water vapor transport over the HRB before the mid 1960s, and the interdecadal variability of the water cycle （precipitation, water vapor transport, etc.） in the summer was related to the PDO; however, interannual variation of the water vapor transport could also be related to the ENSO phenomena.

Impact of Meteorological Drought on Streamflow Drought in Jinghe River Basin of China

Under global climate change, drought has become one of the most serious natural hazards, affecting the ecological environment and human life. Drought can be categorized as meteorological, agricultural, hydrological or socio-economic drought. Among the different categories of drought, hydrological drought, especially streamflow drought, has been given more attention by local governments, researchers and the public in recent years. Identifying the occurrence of streamflow drought and issuing early warning can provide timely information for effective water resources management. In this study, streamflow drought is detected by using the Standardized Runoff Index, whereas meteorological drought is detected by the Standardized Precipitation Index. Comparative analyses of frequency, magnitude, onset and duration are conducted to identify the impact of meteorological drought on streamflow drought. This study focuses on the Jinghe River Basin in Northwest China, mainly providing the following findings. 1) Eleven meteorological droughts and six streamflow droughts were indicated during 1970 and 1990 after pooling using Inter-event time and volume Criterion method. 2) Streamflow drought in the Jinghe River Basin lagged meteorological drought for about 127 days. 3) The frequency of streamflow drought in Jinghe River Basin was less than meteorological drought. However, the average duration of streamflow drought is longer. 4) The magnitude of streamflow drought is greater than meteorological drought. These results not only play an important theoretical role in understanding relationships between different drought categories, but also have practical implications for streamflow drought mitigation and regional water resources management.

Environmental Characterization of Periphyton Community

The present paper deals with the behavior of the Attached Microbial Community (AMC) for water self-purification at different riverbeds in a typical local river. The study quantitatively investigated the problem starting with in-situ sampling. It was found that more biomass of AMC was at riffles with wider distribution than in pools. High current velocity (HCV) plays a negative role at the initial stage of attachment on the riverbed, but HCV aids the community proliferation after stable attachment. External disturbances such as rainfalls and discharges from dams or reservoirs would detach the periphyton depending on the intensity of turbulence in water. However, it was discovered that the flock of periphyton could be restored very quickly because it was not completely removed. Thus, in order to enhance self-purification by periphyton, a suitable configuration of the riverbed must be constructed, and occasional appropriate repair along the channels would improve the decontamination of the river.

Applications of GSTARS Computer Models for Solving River and Reservoir Sedimentation Problems

GSTARS (Generalized Sediment Transport model for Alluvial River Simulation) is a series of computer models developed by the U.S. Bureau of Reclamation while the author was employed by that agency. The stream tube concept is used in all GSTARS models which allow us to solve one-dimensional equations for each stream tube independently and obtain semi-two-dimensional variation of the hydraulic conditions along and across stream tubes for rivers and reservoirs. Sedi-ment transport, scour, and deposition processes are simulated along each stream tube independently to give us a semi-three-dimensional variation of the bed geometry. Most sediment transport computer models assume that channel width is given and cannot change during the simulation process. GSTARS models apply the theory of minimum stream power to the determination of optimum channel width and channel geometry. The concepts of channel side stability, and active, inactive, and armoring layers are used in all GSTARS models for realistic long-term simulation and prediction of the scour and deposition processes in rivers and reservoirs.GSTARS models have been applied in many countries for solving a wide range of river and reservoir sedimentation problems. Case studies will be used to illustrate the applications of GSTARS computer models.

Detecting Changes in Precipitation and Temperature Extremes over China Using a Regional Climate Model with Water Table Dynamics Considered

Simulations were conducted with the regional climate model RegCM incorporating water table dynamics from 1 September 1982 to 28 August 2002 to detect precipitation and temperature extremes. Compared with observed r10(number of days with precipitation ≥ 10 mm d–1), RegCM3_Hydro(the regional climate model with water table dynamics considered) simulated rain belts, including those in southern China and the middle and lower reaches of the Yangtze River, and provided data for arid to semi-arid areas such as the Heihe River Basin in northwestern China. RegCM3_Hydro indicated a significant increasing trend of r95p(days with daily precipitation greater than the 95th percentile of daily amounts) for the Yangtze, Yellow, and Pearl River basins, consistent with r95p observations. The Haihe River Basin was also chosen as a specific case to detect the effect of groundwater on extreme precipitation using peaks over threshold(POT)-based generalized Pareto distribution(GPD) with parameters estimated by the L-moment method. Quantile plots showed that all but a few of the plotted points were distributed near diagonal lines and the modeled data fitted well with the samples. Finally, the effects of water table dynamics on temperature extremes were also evaluated. In the Yellow River Basin and Songhuajiang River Basin, the trends of the number of warm days(TX95n) from RegCM3_Hydro matched observed values more closely when water table dynamics were considered, and clearly increasing numbers of warm days from 1983 to 2001 were detected.

Characteristics and Effects of Inorganic Nitrogen in East Water-source and Inflow Rivers of Chaohu Lake

[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitrogen （DIN） in east water-source and inflow rivers of Chaohu Lake were investigated, and their effects on water qual- ity were examined. [Result] The concentrations of NH3-N and NO2--N were the high in flood season, and low in non-flood season, while the concentration of NO3--N pre- sented the opposite trend; the concentration of NO3--N was the highest in Shuangqiao estuary, where the pollution was the worst. DIN in Zhegao estuary and Xiaozhegao estuary was mainly caused by domestic sewage and industrial wastewaters; surface runoff and pollution from ships contribute the most to the DIN content in Shuangqiao estuary. [Conclusion] This study provided basic data and theoretical basis for the control and management of eutrophication in Chaohu Lake.

Responses of terrestrial water cycle components to afforestation within and around the Yellow River basin

Reforestation has attracted worldwide attention because of its multiple environmental benefits,but its impact on water resources is complicated and still controversial. In this study, the authors conducted numerical experiments within and around the Yellow River basin under the Grain-forGreen project using the Weather Research and Forecasting model. The results showed that the terrestrial water cycle process was sensitive to land use/cover change in the study region. Under the increase of mixed forests within and below the basin, the basin-averaged precipitation and evaporation increased by 223.17 and 223.88 mm respectively, but the surface runoff decreased by 2.22 mm from 2006 to 2010. In other words, the forest-induced increase in evaporation exceeded that of precipitation along with decreased surface runoff. Importantly, the afforestation effects on water resources seemed to enhance with time, and the effects of the same vegetation change were different in dry and wet years with different precipitation amounts(i.e. different atmospheric circulation background). It should be noted that it is difficult to obtain one product that can explicitly reflect the spatial distribution of actual land cover change promoted by the Grain-for-Green project in the Yellow River basin, which is an important obstacle to clearly identify the reforestation impacts. A land cover dataset derived from advantages of multiple sets of data therefore needs to be proposed.

Oasis System and Its Reasonable Development in Sangong River Watershed in North of the Tianshan Mountains,Xinjiang,China

Under the guide of system theory, taking the oasis in the Sangong River watershed as a case study, this paper analyzes the oasis structure and function from 4 aspects including oasis spatial structure, water resources structure, vegetation structure, economic structure and their corresponding functions. The results indicate that as a typical small-scale watershed, Sangong River watershed has the relatively complete mountain-basin structure, and ecological and productive function. Because of human drastic activity the utilization rate of water resources was as high as 98.7%, and the utilization of groundwater was not reasonable, which resulted in an average annual decline of 0.353m in the water table of alluvial-diluvial-fan oasis, and an average annual increase of 0.047m in the alluvial-plain. The layout of crop and shelter forest benefits to the utilization of water and land resources. The development of oasis economy is at low level, and its eco-economic function is weak.