Study region: Mu Us Sandy Land, China. Study focus: The groundwater table in unconfined aquifers is often a subdued replica of the topography or land surface. In hilly terrain, spatial interpolation methods are prone to errors such as higher interpolation water level than the ground surface due to sparse observation wells. Meanwhile, in ridge areas, groundwater depth can easily be overestimated with limited groundwater observations. To address these issues, this paper proposes a framework to learn groundwater depth using related groundwater variables based on the extreme gradient boosting (XGB) machine learning method. Moreover, the groundwater level map is drawn based on the predicted groundwater depths and elevation data.New Hydrological Insights for the RegionThe results obtained by the XGB algorithm are compared with those of common interpolation methods (including inverse distance weighting, ordinary kriging, and collaborative ordinary kriging) and machine learning methods (including multiple linear regression, geographically weighted regression, support vector regression, and random forest). The results showed that the XGB using the Tweedie loss function performs best in learning groundwater depth compared with interpolation methods and other machine learning methods, and almost completely overcomes the effects of imbalanced data. The topographic factors such as elevation, topographic position index, and topographic roughness index are key factors for groundwater depth. This study provides a reference for improving regional GL mapping, especially in areas of complex terrain.

为了科学分析近年来河北省地下水饮用水源地的水质状况,以河北省42个地下水饮用水源地2000、2018年的24项指标作为评价对象,结合单一指标评价法与综合评价法分析水质状况,并进行原因分析.结果 表明:相较于2000年,2018年19项水质指标污染程度均减轻,氟化物污染程度较重,新增4项超标水质指标;安全水源地比例增加了11.9％,且极差水源地消失,但优良水源地也消失;水源地保护区内耕地面积减小,林地面积增大,建设用地面积增大,农业污染面积减小,工业和生活污染面积增大;污染物主要来源于农业化肥、工业废水和生活垃圾污染3个方面,且地下水超采也会对水质造成影响.研究结果可以对河北省地下水饮用水源地管理和保护提供科学依据和实践支撑.

在分析研究咸水入侵演化机理的基础上,对地下水超采综合治理的压采、水源置换,以及人工回灌和地下水水库开发等方案模拟分析,提出潍北平原区分区分期地下水水位水量双控指标,为潍北地区咸水入侵治理与监控提供依据.同时,形成面向海咸水入侵治理与监控、可推广应用的区域地下水管理模式.

河流健康是指河流具有良好自然生态和可持续的社会服务功能.以多维河流健康评价为架构,提出了包括河流水文学、水化学、水生态、河流物理结构及社会经济服务功能等方面指标的河流健康评价指标体系,分析评价《石羊河流域重点治理规划》实施以来,流域河流健康趋势,结果表明:2016年流域植被指数相较于2006年明显提高,流域生态环境明显改善;流域河流健康水平逐步提高,流域治理效果显著.

地下水位埋深情况对我国西北干旱半干旱区的植被生长具有重要影响,高分系列卫星的发射使从宏观尺度上更加准确地分析植被与地下水位变化的关系成为可能.本文利用2013年8月的高分一号(GF-1)影像数据计算归一化植被指数(NDVI),利用地下水位观测资料及水文地质资料建立地下水模型,从宏观尺度分析了酒泉东盆地的植被与地下水位间的关系.研究表明:酒泉东盆地地下水浅埋区适宜植被生长的地下水位埋深范围为2.0～5.6m之间;NDVI值随坡度增加而逐渐减小,不同坡向上整体的NDVI均值差异不大,但不同区间的NDVI值在各坡向的分布上有所差异;使用GF-1影像可显著提高NDVI分析的精度.

酒泉盆地位于河西走廊讨赖河流域中游,盆地内地表水和地下水多次相互转换,水循环同时受上游来水、地表引水和地下水开采等因素影响,水循环和地下水动态变化影响中下游用水和湿地生态.文章开发了盆地地表水和地下水转换模拟模型,分析了不同情景来水用水地下水动态、泉水溢出量以及鸳鸯池水库入库水量变化.模型模拟分析表明,现状来水和水资源开发利用水平下,地下水处于负均衡状态.酒泉盆地地下水库的调蓄作用巨大,天然来水的变化引起地下水水位和泉流量变化,对鸳鸯池水库入库水量影响不显著.目前,把井渠混合灌区内地下水水位下降趋势的区域都划分为超采区是不合理的,建议对划分的地下水超采区进行进一步论证.

利用盆地尺度地下水数值模拟预测模型,分析了红崖山水库加高扩建后民勤盆地生态用水调度方案,以及北部湖区生态恢复趋势.分析表明,红崖山水库加高后通过生态调水,预计在绿洲外围形成面积可观的条带状地下水浅埋分布区,对于阻止沙漠化将起到积极作用.建立生态补水长效机制对于民勤盆地生态修复和维持十分关键.

水生态文明建设对新疆稳定及兵团发展意义重大.分析了石河子市自然及社会经济条件,阐述了石河子市发展模式转变及存在的瓶颈制约问题,提出了未来向生态兴边战略转变的建议,探索了山、水、林、田、城系统规划和全面建设“蓝色八师”的总体思路及布局并提出一些重要建议,如政策扶持、外流域补水、体制改革等.

As an important ecological security barrier of north China,the Huangqihai Lake wetland is a farmingpastoral ecotone with extremely fragile ecological environment.The wetland suffers from the serious degradation caused mainly by the irrational exploitation of water and land resources as well as the drying of climate change during recent decades.In this paper,the main causes of wetland degradation were discussed,and it was considered that the lake drying-up was directly caused by the over-pumping of groundwater from the confined aquifers in the basin.The lake water balance model was developed to simulate the interaction of surface water and groundwater by using the numerical groundwater flow model.The inflows of the lake were calculated,and the results revealed that the water areas in normal,high-flow and low-flow years were 29.83 km2,31.67 km2 and 23.79 km2 respectively.The results of monthly water balance illustrated that the largest water area occurred in December instead of rain sea-son,this was quite different from the previous hydrological results of the lake.The sustainable water areas of the lake for regenerating the ecology in the future were determined based on analyzing the hydrological regime,and they would be 20 km2 and 30 km2 in 2020 and 2030 respectively.The research results could be referred in planning the water resources exploitation and conserving the wetland in the basin.

讨论了新的水资源配置格局下,石羊河流域六河水系水资源需水形势,提出了武威南盆地地表水和地下水联合调度方案.利用盆地尺度地下水数值模拟预测模型,分析了调度方案条件下地下水水位动态和泉流量变化趋势,并分析了入库断面长系列来水过程.分析表明,通过盆地水资源和外调水资源联合调度,满足社会经济需水同时,盆地地下水水位逐步得到恢复,红崖山入库来水满足要求.

2014年青海省海北藏族自治州被列入第二批国家水生态文明建设试点城市.在简要概括了海北州经济社会和自然环境特点的基础上,介绍了海北州水生态文明建设目标和总体布局,梳理出海北州水生态文明建设9项重要行动,对当前及今后水生态文明建设工作提出建议.

The south-to-north water diversion middle route project will greatly ease the contradiction of water supply and demand in Xingtai.Reasonable reduction in exploitation and recharge of the karst groundwater can raise the groundwater levels and even lead to the re-upwelling of the Baiquan spring.In this paper,a numerical model of the karst groundwater was built for the catchment area of the Baiquan spring Near Xingtai.The model was used to quantitatively evaluate the implementation effect of various technical solutions by simulating different schemes of water transfer,including reduction in exploitation and recharge.The feasibility of re-issuing of the spring is proved,which provides a scientific basis for the scientific development objectives and measures for the Baiquan spring.

In order to observe the changing situation of Xihu wetland resources and the trend features in the future in Dunhuang oasis,gray model was used to simulate the wetland evolution and tendency based on the different types of wetland data obtained from remote sensing images. The results are shown as follows:( 1) The wetland in Xihu Nature Reserve decreased by 42. 5% in last 34 years and it will continue shrinking in the following10 years while the sand and gobi area will increase.( 2) The plaque of wetland is progressively diminishing which reflects the fragmentation of wetland changing. Topography also affected the variation of wetland.( 3) The precision of the gray model simulation on wetland evolution is relatively high and it will be a feasible method for wetland research.

Numerical weather prediction (NWP) models are gaining more and more attention in providing high-resolution rainfall forecasts for real-time flood forecasting. In this study, the weather research and forecasting (WRF) model is integrated with the probability distribution model (PDM) to make real-time flow forecasts in a small catchment located in Southwest England. In order to improve the accuracy of the NWP rainfall and flow forecasts, dual real-time updating is carried out in the forecasting system through data assimilation. The three-dimensional variational data assimilation technique is coupled with the WRF model to assimilate radar reflectivity and traditional meteorological data; meanwhile, the autoregressive moving average model works with the rainfall–runoff model PDM to assimilate real-time flow observations. Four 24-h storm events with different characteristics of rainfall–runoff responses are selected from the study catchment to test the performance of the constructed forecasting system. The flood forecasting accuracy is found to be largely improved by incorporating the NWP forecasted rainfall when the lead time is beyond the catchment concentration time. The assimilation of radar and meteorological data also shows great advantage in improving the NWP rainfall forecasts.

In this paper,BPANN model was built to describe river pattern of a river from 1980 to 2008. The results show that the main factors affect the change of the river pattern are the type of rock,type of landform and descending of the land along the river. Following factors are those of depth right by the river,curvature of river course and type of bank line. Soil and depth near the river centre affect little to the river pattern.

Projection pursuit regression is a statistical model which adapts the additive models in that it first projects the data matrix of explanatory variables in the optimal direction before applying smoothing functions to theses explanatory variables. This paper mainly discusses the projection pursuit regression (PPR) model developed for analysis of the relationship between the precipitation and the runoff from Heilongtan spring in Lijiang basin of Yunnan Province of Southwest China. A long series precipitation data of four rainfall stations and the spring flow monthly data from year 2001 to 2011 are used for establishing of PPR model. The results illustrate that the spring flow is lagging behind the rainfall about 120days, and is much significantly relative to the precipitation of Lijiang rainfall station which is located in plain area and near the springs, instead of the precipitation of Jiuzihai, located in recharge area, higher mountain area. This is because the variation of precipitation in plain area causes the change of groundwater level of pore aquifers in plain areas, and affects the spring flow of karst groundwater which directly hydraulic-connected with pore aquifers in plain area. The precipitation in recharge area also affects the variation of spring flow of karst groundwater, but not very significantly, because of the regulation of huge storage of karst aquifers. The research results could be very meaningful for the scientific development and planning of water resources as well as the protection of the karst springs in Lijiang basin.

The runoff from Heilongtan karst springs is the main water source for the scenery use of the well-known Old Town of Lijiang located in Yunnan Province of Southwest China. The spring flow is in dependence of rainfall and may be dry for long period in years with less precipitation in the basin. This paper discusses the various engineering schemes of maintaining the runoff from Heilongtan Spring by using the karst groundwater numerical simulation model. Firstly, the hydrogeological concept model is established by analyzing the investigation data including geophysics, groundwater level dynamic characteristic and aquifer geological survey information. Then the numerical simulation model is calibrated and verified by utilizing the long series data of the groundwater level, spring flow observations, and precipitation. Two major schemes, one is artificial recharge by delivering water from nearby basin, another is building the groundwater reservoirs by underground dam in karst aquifers, are simulated with the numerical simulation model. The results of scenario analysis demonstrate that both schemes are feasible for maintaining the runoff from Heilongtan Spring. Considering the cost of the engineering, the authors prefer the underground dam scheme which may be more reasonable and the spring could be guaranteed to overflow even in years with very less rainfall in the basin. As to the scheme of delivering water of near basin, about 49 percent of the delivering water is discharged by the way of underground flow. Therefore, it may not be guaranteed the spring flow not to be dry in year with very less rainfall. Lastly, the development pattern of cascade groundwater reservoirs is suggested to fully develop water resources for regional industrial, agricultural, domestic as well as scenery water use.

Groundwater model is set up to calculate ecological water requirements in Baoding,Hebei Province.Modeling results show that a total of 6.4×107 m3 groundwater is consumed annually under current situation which leads to continual decline of groundwater level.Modeling scheme is designed considering reducing groundwater yield and restoring water body of Baiyangdian to that of 1975.The results show that it is possible to restore water body of Baiyangdian to that of 1975 with an annual groundwater supplement of about 8.0×107 m3 while reducing groundwater yield by 1.47×108 m3.The groundwater level reaches ecological level.Ecological water requirements is about 1.5×109 m3.This study is of importance to groundwater eco-environment restoration in semi-humid area and semi-arid area.

Based on analyses of theoretical models of the fathoming method by using satellite remote sensing, we determined the most suitable spectral band for water depth retrieval using the SVC HR-1024 spectroradiometer.A water depth remote sensing model for the Wusuli River was established and its accuracy improved by analyzing the sensitivity to water of different bands of the HJ-1a CCD camera output.Our results show that the acquisition of water depth from remote sensing could supply a new and more rapid way for obtaining the talweg, river terrain information and information on river pattern change for the Wusuli River.