Determining safe yield and mapping water level zoning in groundwater resources of the Neishabour Plain

Groundwater is a crucial sources of water supply,especially in arid and semi-arid areas around the world.With uncontrolled withdrawals and limited availability of these resources,it is essential to determine the safe yield of these valuable resources.The Hill method approach was used in this study to determine the safe yield the Neishabour aquifer in Khorasan Razvi province in Iran.The results showed that the safe yield in the Neishabour aquifer is 60%lower than the current pumping amounts during the study period,indicating that further overdrafts could result in the destruction of this aquifer.This highlights the importance of using the Hill method to estimate the permitted exploitation from other aquifers,thus preventing problems caused by over-extraction and maintaining stability of global groundwater levels.

Development and prospect of downhole monitoring and data transmission technology for separated zone water injection

This article outlines the development of downhole monitoring and data transmission technology for separated zone water injection in China.According to the development stages,the principles,operation processes,adaptability and application status of traditional downhole data acquisition method,cable communications and testing technology,cable-controlled downhole parameter real-time monitoring communication method and downhole wireless communication technology are introduced in detail.Problems and challenges of existing technologies in downhole monitoring and data transmission technology are pointed out.According to the production requirement,the future development direction of the downhole monitoring and data transmission technology for separated zone water injection is proposed.For the large number of wells adopting cable measuring and adjustment technology,the key is to realize the digitalization of downhole plug.For the key monitoring wells,cable-controlled communication technology needs to be improved,and downhole monitoring and data transmission technology based on composite coiled tubing needs to be developed to make the operation more convenient and reliable.For large-scale application in oil fields,downhole wireless communication technology should be developed to realize automation of measurement and adjustment.In line with ground mobile communication network,a digital communication network covering the control center,water distribution station and oil reservoir should be built quickly to provide technical support for the digitization of reservoir development.

Using geospatial technologies to delineate Ground Water Potential Zones(GWPZ)in Mberengwa and Zvishavane District,Zimbabwe

The main objective of the study was to delineate Ground Water Potential Zones(GWPZ)in Mberengwa and Zvishavane districts,Zimbabwe,utilizing geospatial technologies and thematic mapping.Various factors,including geology,soil,rainfall,land use/land cover,drainage density,lineament density,slope,Terrain Ruggedness Index(TRI),and Terrain Wetness Index(TWI),were incorporated as thematic layers.The Multi Influencing Factor(MIF)and Analytical Hierarchical Process(AHP)techniques were employed to assign appropriate weights to these layers based on their relative significance,prioritizing GWPZ mapping.The integration of these weighted layers resulted in the generation of five GWPZ classes:Very high,high,moderate,low,and very low.The MIF method identified 3%of the area as having very high GWPZ,19%as having high GWPZ,40%as having moderate GWPZ,24%as having low GWPZ,and 14%as having very low GWPZ.The AHP method yielded 2%for very high GWPZ,14%for high GWPZ,37%for moderate GWPZ,37%for low GWPZ,and 10%for very low GWPZ.A strong correlation(ρof 0.91)was observed between the MIF results and groundwater yield.The study successfully identified regions with abundant groundwater,providing valuable target areas for groundwater exploitation and highvolume water harvesting initiatives.Accurate identification of these crucial regions is essential for effective decision-making,planning,and management of groundwater resources to alleviate water shortages.

Study of coastal water zone ecosystem health in Zhejiang Province based on remote sensing data and GIS

The coastal ecosystem health assessment is a field of increasing importance.In this paper,a preliminary assessment of ecosystem health in Zhejiang coastal water zone was made,mainly based on remote sensing data and GIS technique.Its spatial and quantitative evaluation was facilitated by the progress of remote sensing and GIS technique development.Firstly,human activities,hydrology and ecosystem problems in the study area were discussed and analyzed.Secondly,from 4 aspects of human stress,physical,chemical and biological responses to anthropogenic activities and natural stress,several indicators such as water transparency（Secchi Disk Depth,SDD）,suspended substance concentration,dissolved inorganic nitrogen,active phosphate,chlorophyll,harmful algae bloom,as well as distribution of sewage,sea lanes and port were employed.Thirdly,the Analytic Hierarchical Process was used for indicator weight calculation,and the ecosystem health criteria were established according to the integrative analysis of national water quality criteria,similar coastal ecosystem health research in other places or data inherent properties.The results indicated that from 2005 to 2007 the coastal water ecosystem health value in Zhejiang Province was unhealthy and needs ecological restoration by human intervention.

Forecasting water disaster for a coal mine under the Xiaolangdi reservoir

Xin’an coal mine, Henan Province, faces the risk of water inrush because 40% of the area of the coal mine is under the surface water of the Xiaolangdi reservoir. To forecast water disaster, an effective aquifuge and a limit of water infiltration were determined by rock-phase analysis and long term observations of surface water and groundwater. By field monitoring, as well as physical and numerical simulation experiments, we obtained data reflecting different heights of a water flow fractured zone (WFFZ) under different mining conditions, derived a formula to calculate this height and built a forecasting model with the aid of GIS. On the basis of these activities, the coal mine area was classified into three sub-areas with different potential of water inrush. In the end, our research results have been applied in and verified by industrial mining experiments at three working faces and we were able to present a successful example of coal mining under a large reservoir.

Design of environmental decision support system and its application to water quality management

EDSS is a comprehensive software system for water quality management in tidal river networks in general and for the Pearl River Delta in particular. Its purpose is to provide a practical tool that could assist government agencies in decision making for the efficient management of water resources in terms of both quantity and quality. By combining the capabilities of geographical information system (GIS), database management system (DBMS), model base management system (MBMS) and expert system, the aim is to improve the quality of decision making in what is becoming an increasingly complex area. This paper first outlines the basic concepts and philosophy adopted in developing EDSS, the system architecture, design features, implementation techniques and facilities provided. Thereafter, the core part of the system—the hydrodynamic and water quality models are described briefly. The final contribution in this paper describes the application of EDSS to the Pearl River Delta, which has the most complicated tidal river network patterns as well as the fastest economic development in the world. Examples are given of the real-world problems that can be addressed using the system, including cross-boundary water pollution analysis, regional drinking water take-up site selection, screening of important polluters, environmental impact assessment, and water quality zoning and planning. It is illustrated that EDSS can provide efficient and scientific analytical tools for planning and decision-making purposes in the information era.

Soil anti-scourability enhanced by herbaceous species roots in a reservoir water level fluctuation zone

Revegetation is one of the successful approaches to soil consolidation and streambank protection in reservoir water level fluctuation zones(WLFZs).However,little research has been conducted to explore the impact of herbaceous species roots on soil anti-scourability during different growth stages and under different degrees of inundation in this zone.This study sampled two typical grasslands(Hemarthria compressa grassland and Xanthium sibiricum grassland)at two elevations(172 and 165 m a.s.l.)in the water level fluctuation zone(WLFZ)in the Three Gorges Reservoir(TGR)of China to quantify the changes in soil and root properties and their effects on soil anti-scourability.A simulated scouring experiment was conducted to test the soil anti-scourability in April and August of 2018.The results showed that the discrepancy in inundation duration and predominant herbaceous species was associated with a difference in root biomass between the two grasslands.The root weight density(RWD)values in the topsoil(0-10 cm)ranged from 7.31 to 13 mg cm^(-3) for the Hemarthria compressa grassland,while smaller values ranging from 0.48 to 8.61 mg cm^(-3) were observed for the Xanthium sibiricum grassland.In addition,the root biomass of the two herbs was significantly greater at 172 m a.s.l.than that at 165 m a.s.l.in the early recovery growth period(April).Both herbs can effectively improve the soil properties;the organic matter contents of the grasslands were 128.06%to 191.99%higher than that in the bare land(CK),while the increase in the water-stable aggregate ranged from 8.21%to 18.56%.Similarly,the topsoil antiscourability indices in both the herbaceous grasslands were larger than those in the CK.The correlation coefficients between the root length density(RLD),root surface area density(RSAD)and root volume density(RVD)of fine roots and the soil antiscourability index were 0.501,0.776 and 0.936,respectively.Moreover,the change in the soil antiscourability index was more sensitive to alternations in the RLD with diameters less than 0.5 mm.Overall,the present study showed that the perennial herbaceous(H.compressa)has great potential as a countermeasure to reduce or mitigate the impact of erosion in the WLFZ of the Three Gorges Reservoir.

Dynamic influence of Holocene characteristics on vadose water in typical region of central North China Plain

In the typical region of central North China Plain, vadose sediments are Holocene sediment strata. With samples from field drillings, the study analyzes the sedimentary characteristics of vadose zone. The study takes the content of silty sand as the basis for sedimentary environment analysis, and the content of clay and sand as the sensitive indicator for sedimentary characteristics. Combining palynology analysis, the study divides vadose zone from top to bottom into diluvia oxbow lacustrine sediments, lacustrine sediments, lacustrine and swamp sediments, weak palaeohydrodynamic lacustrine sediments and alluvial sediments. Based on the sedimentary characteristics of Holocene strata, it analyzes the changes across depth of vadose zone water potential and matrix potential, obtaining the influence of vadose zone sedimentary characteristics on the migration of water in typical region of central North China Plain.

Protection and Ecological Restoration of Water Level Fluctuation Zone in the Three Gorges Reservoir

Water level fluctuation zone(hereinafter referred to as "WLFZ") is a transitional ecosystem between terrestrial ecosystem and aquatic ecosystem,and also a key area to control its neighboring terrestrial and aquatic ecosystem. After the Three Gorges Reservoir was put into use,ecological environment of its WLFZ has aroused wide concern from domestic and foreign experts. On the basis of introducing characteristics of WLFZ of the Three Gorges Reservoir,current ecological environment and main problems of this area were analyzed,plant selection and configuration was elaborated as well as the implementation effect of many WLFZ protection and ecological restoration modes. In view of the actual conditions,pertinent suggestions were proposed for WLFZ of the Three Gorges Reservoir,namely classified protection and ecological restoration,enhancing monitoring and assessment of current situation and change tendency,carrying out technical researches and demonstration of WLFZ wetland ecological restoration.

Horizontal-Longitudinal Spatial Correlation of Acoustic Field with Deep Receiver in the Direct Zone in Deep Water

The horizontal-longitudinal correlation of acoustic field for the receiver near the bottom is analyzed by using nu- merical modeling. An approximate analytical solution of horizontal-longitudinal correlation coefficient is derived based on the ray method. Combining the characteristic of Lloyd＇s mirror interference pattern, the variability of acoustic field and its effect on horizontal-longitudinal spatial correlation are discussed. The theoretical pre- diction agrees well with the numerical results. Experimental results confirm the validity of analytical solution. Finally, the applicability of the analytical solution is summarized. The conclusion is beneficial for the design of bottom-moored array and the estimation of integral time for moving source localization.

Analysis of Water Quality Variation and Trend in the Ji'an Section of the Ganjiang River

Based on the monitoring data of water quality in the Ji'an section of the Ganjiang River from 2008 to 2018 by the Water Resources Monitoring Center of Ji'an City,single factor evaluation method,comprehensive pollution index method and seasonal Kendall test method were adopted to study and analyze the characteristics of surface water resources and the changing trend of water quality in the river section.The results show that the water quality in the Ji'an section of the Ganjiang River was generally good,and the water quality of each function zone reached the target requirement.The comprehensive pollution index was controlled between 0.21 and 0.40 over the years,and there was no significant change in time and space,and the water quality was relatively stable.The dissolved oxygen and permanganate index tended to improve,and there was no change in five-day biochemical oxygen demand,while ammonia nitrogen and total phosphorus showed an upward trend.The water quality as a whole showed a trend of deterioration.By discussing the influencing factors of the characteristic pollutants,the causes of water quality in the Ji'an section of the Ganjiang River were further analyzed.It is suggested to strengthen the supervision and control of non-point source and point source pollution.

Height Detection and Analysis of Water Flowing Fractured Zone of Coal Face

Taking 91105 working face as the research object, the observation method of water flowing fractured zone and the layout of mining holes were determined by analyzing the field geological structure. It was shown that the fractured zone height and the ratio given by the measured method were 52.33 and 12.46, respectively. By the numerical simulation method with the software of UDEC, the fractured zone height and the ratio were 42.5 and 10.12. By comparison of measured height data and UDEC numerical simulation, there were some differences between the measured height and the calculated results of UDEC numerical simulation method. The method of simulation can be used as the technical basis for the design of waterproof coal pillar in the future.

The primary controlling parameters of porosity, permeability,and seepage capability of tight gas reservoirs:a case study on Upper Paleozoic Formation in the eastern Ordos Basin,Northern China

Tight sandstone gas(hereafter"tight gas")has become a subject of unconventional gas exploration globally.The large-scale development and use of tight gas resources in the USA,in particular,facilitated the rapid rebound of natural gas production in the USA,in addition to driving the rapid development of tight gas worldwide.In the eastern Ordos Basin,the Upper Paleozoic feature includes multiple layers of gas,a shallow depth,and notable potential for exploration and development.However,the reservoirs in the area are relatively tight,exhibit strong heterogeneity,and possess a complex micropore structure,thus restricting the eff ective economic development of oil and gas.Thus,research on the primary parameters controlling pore throat structure and the seepage capability of low-permeability reservoirs will be beneficial for the effcient exploration and development of natural gas in the eastern Ordos Basin.The parameters of reservoir porosity and percolation ability,as well as permeability,were analyzed using systematic sampling of the of the Upper Paleozoic Benxi,Taiyuan,and Shanxi Formations in the eastern Ordos Basin,constant-rate mercury injection experiments,nuclear magnetic resonance analysis,and gas–water-phase experimental studies.The results indicate that reservoir porosity is controlled by the effective pore volume and number,whereas permeability is controlled by the largest throat radius,rather than the average.The effective pore volume controls the movable fluid saturation,while reservoir percolation capability is controlled by the effective pore volume,irreducible water saturation,and size of the gas–water two-phase seepage zone.

Surveying on two-zone height of sublevel strip mining

The site drilling packer permeability test and TEM to the 2100 workface in Gucheng coalmine determined the two-zone height under sublevel strip mining.The conclusion considers that the lying strata deterioration law of the strip mining is similar to that of the sublevel mining.Thus, against that the actually measured data lacked, it is feasible to refer to the reservation of the waterproof coal pillar in the neighbor coalmine under sublevel situation.However, it is necessary to further launch the research on lying strata deterioration law under sublevel striping mining for the purpose of providing the right foundation for the layout of the workface not mined so far and the reservation of the waterproof coal pillar in the mining area.

Fractured zone height of longwall mining and its effects on the overburden aquifers

As mining depth becomes deeper and deeper,the possibility of undermining overburden aquifers is increasing.It is very important for coal miners to undertake studies on the height of fractured zone during longwall mining and the effects of longwall mining on the underground water while mining under surface water bodies and underground aquifers.In order to study this problem,piezometers for monitoring underground water levels were installed above the longwall panels in an American coalmine.Large amounts of pre-mining,during mining and post-mining monitoring data were collected.Based on the data,the heights of fractured zones were obtained and the effects of longwall mining on the underground water were studied.The results demonstrate that when the piezometer monitoring wells had an interburden thickness of less than 72.7 m,the groundwater level decreased immediately to immeasurable levels and the wells went dry after undermining the face of longwall.The height of the fractured zone is 72.7-85.3 m in the geological and mining conditions.The results also show that the calculated values of fractured zones by the empirical formulae used in China are smaller than the actual results.Therefore,it is not always safe to use them for analyses while mining under water bodies.

Research on the Operational Conditions of Artificial Precipitation Enhancement in Liaoning Province

Taking precipitation process during May 17-18,2009 as an example,this paper analyzed and summarized the operational conditions of artificial precipitation enhancement in Liaoning Province.Operational conditions can be divided into two categories,namely,macro-weather and cloud micro-physical operational conditions,this paper described their respective indexes and criterions as well as their effect and application in formulation and command of artificial precipitation enhancement plan real-timely.

THE FEATURE AND EVALUATION OF ECOTONE IN CHINA

Based on explicating the definition of ecotone, this paper discussed emphatically the distribution and features of joint zone between land and water, transition zone between mountains and plains, and intersection zone between agricultural and animal husbandry regions. The geographic environment of the three ecotones were evaluated, their developing tendency predicted and the corresponding measures to be taken in the 21st century pointed out.

Optimum Calculation of Coal Pillars in Inclined Weathered Oxidation Zone

In the mining process of coal mine,waterproof coal pillars should be set between the weathered oxidation zone and the first mining face.In order to determine the reasonable upper limit of the first mining face of Hongyi Coal Mine,the waterproof coal pillar needs to be wide enough to resist the lateral hydrostatic pressure of the oxidation zone,and to ensure that the top plate aquifer does not run through the water guide crack zone,while also liberating as much stagnant coal as possible.In this paper,the first coal mine face’s waterproof coal pillar was calculated using conventional and optimized calculation methods,taking into account the dip angle of the coal seam,the height of the water-guide crack zone,and the rock shift influence zone,and finally the upper limit of the first face of Hongyi Coal Mine was determined.