Abstract:Road erosion in the loess region is a severe problem which influences traffic,transportation and agricultural activities etc.Research on road erosion is very important to soil and w ater conservation,ecology construction and economy development in the region.Based on simulated rainfall experiments,erosion processes on loess roads are studied,and following results are obtained.(1)The variations of starting time of soil erosion by runoff with rainfall intensity and slope gradient can be respectively described with exponential equations.(2)The sediment concent ration is very high in the initial stage of soil erosion processes by runoffon road.However,the concent ration decreases very quickly,and then gradually becomes relative steady in continued rainfall processes.(3)The variation of road erosion rate can be divided into three stages during which the variation of erosion rate with rainfall process is great from the commence of soil erosion by runoff to 20min,and from 40min to the end of runoff erosion processes,and is relatively steady from 20min to 40min.(4)The variations of road erosion modulus with rainfall intensity and slope gradient can be described with exponential equations,respectively,and the integrated effects of rainfall intensity and slope gradient on road erosion can be described with a binary linear equation.

Abstract:Wind erosion is a significant factor limiting agricultural development in the north ecotone between agriculture and pasture. In order to study the mechanisms of windbreak,sand-fixation and protection benefits in shelter belts,wind erosion under three types of protective forest model was simulated in a wind tunnel experiment using the PIV system.Threshold shear velocity and wind erosion rate were measured,and velocity characteristics were obtained by using InsightNT softw are. Results show that the combination between arbor and shrub is a best protective forest structure model.The reason is that the structure model can significantly reduce wind velocity on soil surface.

Abstract:Labile organic carbon( LOC) is the most active part of soil organic carbon,and it is more sensitive to environment change. This paper studied the effect of soil erosion on LOC with field run off??plot observation and laboratory analysis.Results show that the LOC content in soil ranged between 0.15 g/ kg and 0.34 g/ kg, and was between 0.28 g/ kg and 2.92 g/ kg in sediment.For a slope gradient less than 20,the amount of LOC loss in creased with increased slope gradient.The enrichment ratio of LOC ranged between 3.25 and 8.47,and was negatively related to erosion rate and slope gradient.The LOC content in sediment decreased prog ressively as a log arithm function with increased soil erosion rate,and the LOC loss degree linearly increased with increased soil erosion rate.

Abstract:Slope gradient has many impacts on soil erosion by water and mineral nitrogen loss in an erosion process.The results from artificial rainfall experiments are as follows.Only in a certain range of slope gradient,the amounts of soil erosion and mineral nitrogen loss aggrandized with the increase in slope gradient.Exceeding the range,how ever,the amounts of the losses decreased.With the same slope length,the crit ical slope gradients for soil erosion and mineral nitrogen loss were validated between 15 and 20.Soil mineral nitrogen loss showed two trends.First,soil mineral nitrogen loss by runoff was much more than that by sediment,being about 99% of the total loss amount.Second,soil nitrate loss in erosion process was the maint rend, being about 96% of the total amount of mineral nitrogen loss.The percent of nitrate lost in surface runoff was much more than that in sediment.Further measures to reduce runoff flow are suggested to control soil mineral nitrogen loss by surface runoff.

Abstract:To study the effects of preferential flow on infilt rated flow and surface runoff in the granite area of the Three Gorges, Yangtze River,China,a soil profile that is not seriously disturbed by human activities was selected in the Quxi watershed of the area as a field experimental site.Preferential flow,infilt rated flow and rainfall were measured by an automatic flowmeter.Surface runoff was measured by an automatic gauge and a thin triangle weir vertically installed at the out let of the watershed.The relationships among preferential flow,infiltrated flow and surface runoff were analyzed.Results showed that during the same rainfall,preferential flow appeared later and stopped earlier than infilt rated flow.The percentage of preferential flow flux over the total infiltrated water can reach 2.40%~ 48.72%.The maximal preferential flow flux can reach 17200 times of that of infilt rated flow,which could increase soil water flux to a great extent.In the same rainfall,the intervention of preferential flow advanced the appearance of peak infilt rated flow,postponed the appearance of peak surface runoff and prolonged the duration of surface runoff.When the amounts of current rainfall and antecedent influenced rainfall are smaller,preferential flow and surface runoff influenced each other more greatly.

Abstract:The spatial variability of soil hydraulic properties influenced by topographic and soil physical and chemical factors is one of the key factors which have considerable effects on water flow and solute transport.An experiment was conduced on a 80m @ 40m plot.Saturated conductivity,Kfs,was measured at a depth of 30 cm,and soil physical and chemical properties were also considered,such as wetness index,bulk density,particle composition,organic matter,exchangeable sodium,CEC and ESP in the 24 sampling sites selected randomly.Based on classic statistics and the Kolmogorov) Smiromov(K)S) normality test,spatialst ructure was analyzed using the GIS+ for Window 5.The result indicated a normal distribution for Kfs,bulk density,organic matter,sand,clay and CEC,a lognormal distribution for exchangeable Na+ and ESP,and auniform distribution for silt.Kfs,bulk density,organic matter,sand,clay,exchangeable sodium and ESP showed the spatial correlation characteristic,but CEC had more distinct spatial heterogeneity than other factors.The influencing factors were also analyzed based on the correlation and PCA method.

Abstract:Soil mechanical composition in the karst area of rocky desertification,Guizhou Province was studied.Results show that with rocky desertification intensified,the content of clay decreased,and the content of sand increased.In the sol profile (A -B -C),clay (smaller than 0.001 mm)g radually increased with depth,whereas sand(in the ranges of 0.01～0.05mm,0.05～0.25mm and 0.25～1mm)gradually decreased.Within the surface layer (0～20mm),the amount of sand decreased,and the amount of clay increased.The content of clay decreased in west part of the area as well.The correlation between the content of clay and organic matter was significantly positive with the correlation coefficient being 0.95.On the contrary,the correlation between sand and organic matter was significantly negative with the correlation coefficient being 0.63.

Abstract:The relationships for hydro-dynamic parameters(Reynolds number,Froude number,resistance coefficient and flow velocity) of overland flowas a function of bed roughness,flow discharge and slope gradient were simulated by means of indoor fixed-bed resistance experiments.The preliminary result indicates that Reynolds number and Froude number of overland flowtend to increase as slope gradient increases in the condition of same bed surface and flow discharge.Reynolds Number and Froude number of overland flow tend to diminish,water flow velocity tends to diminish,and resistance coefficient tends to increases as bed surface roug hness increases in the condition of same slope gradient and flow discharge.It shows that consumed energy for working of water flow against resistance tends to increase.

Abstract:137Cs activities in purple surface soil on grass land have a good relationship with the medium grain size (d50) by sieving method,but do not have a defined relationship with the medium grain size (d50) by normal method. 137Cs is mainly absorbed to surfaces of soil particles, and 137Cs concent rations of the mineral and rock particles in surface layers of the aggregates should be higher than those of the particles in the inner layers of the aggregates. As organic concent rations of the samples of medium size are higher than those of both coarse and fine samples, there is no relationship between 137Cs activities and organic concent rations.

Abstract:By using 11 indexes of statistics between 1996 and 2000 and canonic correspondence analysis (CCA) method, spatial differentiat ion pat tern of production structure (combinat ion and propo rtion of faming-livestock raising-forestry)is analyzed.First, independent variable group and dependent variable group of CCA are defined. Second, by apply ing CANOCO4.5 and CANODRAW4.1 software, the study area is divided into 5 types of production structure :farming, farming-to-livestock raising, livestock raising-to-farming, fo restry and livestock raising.Finally, through a discussion on the spatial dif ferent iation, the 5 types of production st ructure distributed from southeast to northw est are found to be farming, farming-to-livestock raising, livestock raising-to-farming,forest ry and livestock raising.

Abstract:The characteristics of sediment transport rate,sediment concentration and accumulative sediment-runoff in slope lengths of 20,40,60m were analyzed based on field simulated rainfall experiments.Results showed that maximum sediment transport rate occurred in 40m slope length at rainfall intensity less than 2mm/ min,while it occurred in 60m slope length at rainfall intensity greater than 2mm/min.Max imum sediment concentration was always observed in 20m slope length in all the experiments.Accumulative sediment-runoff was prone to be steady with time.The study implies that the measures such as farming along contour,which increases the roughness value of slope and changes slope form,should be taken to reduce high sediment concentration and sediment transportrate,and thus control soil and water loss on loess slope.

Abstract:Based on observed meteorological data and measured soil loss data from field runoff plots in 1985-1992 at Ansai Comprehensive Experimental Station, the applicability of WEPP model to different slope lengths on hil-lgully region of the Loess Plateau was assessed. Results showed that simulated values of event runoff, annual runoff, and average annual runoff by WEPP model were not desirable for the slope lengths of 10 m, 20 m, 30 m and 40 m. How ever, the simulated values of event soil loss and annual soil loss by WEPP model were desirable for the slope leng ths of 10m, 20m, 30 m and 40 m, respect ively. The differences of simulated values between slope lengths and increasing trend with increase of slope length were close to observed data of the soil loss. The Nash-Sutcliffe model ef ficiencies of event runoff simulat ion and annual runoff simulation were 0.915 and 0.879, respectively; and the Nash-Sutcliffe model efficiencies of event soil loss simulat ion and annual soil loss simulat ion were 0.853 and 0.758, respect ively. The simulated accuracy of annual average runoff and soil loss by WEPP model ws satisfied. I30 had a great effect on runoff simulated values at individual storms; the error between simulated values and observed data probably increased when I30 was hig her than 0.92mm/ min. The soil loss simulated values at individual storm had a close correlat ion with PI30, and the error betw een simulated values and observed values increased when PI30 was greater than 129mm2/ min.PI30was an important factor affect ing simulated accuracy of WEPP model, and simulated accuracy decreased when the PI30 was higher than 150mm 2/ min;meanw hile, the effect of PI30 on runoff simulation was more greater than that on soil loss.

Abstract:As a physical index to express the information on topography, topographic index is a very important parameter for many physically based hydrological models. This article analyzes the topographic index based on a small tested loess watershed. The topographic index is derived f rom DEMs of the watershed by using the single flow direction method. Result s show that the spatial dist ribution of the topographic index has a high correlation with terrain dist ribution. Average topographic index variance has an exponential relationship with average slope variance.Frequency dist ribution of the topographic index shows a regular change with changed topography. The analysis of the topographic index variance can help us study catchment topography and hydrological similarity.

Abstract:GLEAMS (Groundw ater Loading Effects of Agricultural Management Systems) model was introduced to test and validate nit rate leaching in an agricultural catchment in southeast China. Field ex periments were performed under dif ferent landuses such as paddy, bananas and veg etables, in Wuchuan catchment of Fujian Province with the area of 9.6 km². Eight boreholes were drilled and monitoring pipes were installed for continuous monitoring of nitrate leaching from April to December in 2002. The hydrologic and nutrient parameters of GLEAMS model were extracted based on measurement sand experiment s during the main crop grow ing season. Model parameters were tuned to achieve desired agreements betw een measurements and model simulations based on sensitivity analysis.After calibration and validat ion, the model generally had acceptable performances in simulating nitrate leaching throug hout the landuses with an exception in paddy field.The model simulations can be used to specifically establish best management practices for nutrient management and pollution mitigation in the catchment.

Abstract:In order to investigate soil erosion conditions and relationship between soil erosion and landuse in Hailun County, an analysis was performed based on GIS using the data of TM images in different periods of 1995 and 2000. Result s showed that dry farm land was the main eroded land type with light and moderate erosion degrees, and slope land was the main type of landuse with an intense erosion degree. Soil erosion rate in 2000 was reduced compared with that in 1995. A good trend was observed after soil and water conservation was implemented in the study region.

Abstract:Based on the comprehensive analysis of climate factor, biological feature and soil humility as well as the experimental data of aspen shelter belt for years, a calculation model for aspen shelter belt evapot ranspiration in the Tarim River basin was built and verified with the evapot ranspiration data directly measured in aspen shelter belt. The result revealed that the model had high precision and could be used to calculate the evapot ranspiration in aspen shelter belt of the Tarim River basin.

Abstract:By taking 5m grid cell DEMs as an experiment basis, the relation between flow accumulation threshold and gully density in the Loess Plateau area, Northern Shaanxi, China, is invest igated quant itat ively and stat ist ica-lly. Experimental results show that a stat istical model could be constructed as a formula. In the formula, the coef f-icient is found to have a strong relat ion w ith terrain complexity and types and play a signif icant role in the model. In the fixed terrain area, a reasonable flow accumulat ion threshold could be derived based on the model, which is of critical significance not only in the theory, but also in application.

Abstract:Taking young pear trees in Jixian Country, Shanxi Province for an example, the paper analyzes the effects of different soil water conditions on physiological characteristics of young pear tree based on a potted exper-iment. The result indicates that the daily change in t ranspirat ion rate presents a single-peak or double-peak curve and the relat ionship between water consumption of pear tree and soil water content can be described significantly by a quadratic curve. Under different soil water conditions, daily chang e in net photosynthetic rate of young pear tree presents/S0 shape, which rises to a peak at 8: 00 am and appears a midday depression of photosynthesis at 12: 00am. Soil water deficient markedly reduces photosynthetic rate. Soil water content suitable for high w ater use ef f-iciency is 10% ~ 14%. The dried weig ht of leaves and total biomass of young pear tree has a downtrend w ith decreased soil water content. U nder the normal soil water condition, the proportions of biomass overground and underground are nearly the same, but the greater photosynthetic production of young pear tree tends to occur in the underground.

Abstract:There are many different factors affecting overland flow, such as climate, geology and vegetation, among which vegetation type is a key factor. In this study, four different vegetation types in J inyun Mountain, Chongqing City, were investigated using the grey rational degree. The analyses of precipitation and vegetation ef2 fect s on overland flow indicate the highest rational degree of precipitation with surface runoff. The parameters contribute to overland flow in the descending order of canopy density, standing foresTheight, litter thickness, slope degree, coverage and soil thickness. The rational degrees of different vegetation types descend in the order of mixed wood, broadleaved forest ry, bamboo forest ry and cropland.

Abstract:With the implementation of the policy of converting slope farmland into forest and grassland, the project has achieved great successes in China. Satellite data of CBERS are used to monitor landuse change for nearly 10 years in the lower reaches of Yanhe River in northern Shaanxi Province, and the change in the spatial st ructure are quantified as well. Result s show that forest was increased by 8 %, grassland was increased by 20%, and farmland was decreased by 38%. 1.03% of farmland was converted into woodland, and 57.49% of farmland, into grassland. Dynamic monitoring of changes in the region’s ecological environment has been achieved, and a viable way to monitor and survey ecological environment and converting slope farmland into forest and grassland in the loess hilly and gully area has been provided.

Abstract:Landscape pattern in Zhangjia valley of the low tabular mountains and hills in Western Chongqing Municipality is studied by using five set s of land use data in 1957,1976,1982,1992 and 1998, quantitative methods of landscape ecology and techniques of RS & GIS. Firstly, landscape is classified into six types of irrigable land, dryland, orchard, woodland, village and watershed, respectively, by using remote sensing images. Secondly, a geographical information system(GIS) is designed and set up based on digital data ext racted f rom remote sensing images, field investigation data and other types of data, and then a digital map of landscape is figured out. Thirdly, depended on spatial analysis function of GIS, indexes for diversity, dominance, f ragment, isolation and f ractal dimension of each landscape type in different periods are calculated. It is found that with time elapsing and economical development, changes in the indexes become complicated and anomalistic. The rhythms of the changes are consistent with agricultural policies, increase in population and economical development. Fractal dimensions of landscape types f rom high to low are village, woodland, irrigable land, dry land, orchard and watershed in turn. Such a rank explicitly shows the complexity of landscape types. It is an effective method to study the processes, patterns and mechanisms of the changes in regional land use and land cover using landscape ecology and the techniques of GIS & RS.

Abstract:The characteristics of soil and water loss and the monitoring situation of development and const ruction project are analyzed. A monitoring indicator system for soil and water conservation is proposed f rom the aspect that monitoring results must reflect dynamic changes in soil and water loss and it's effects. At last, the monitoring method of each indicator is presented.

Abstract:Based on the spatial analyses of GIS, the normalized factors are overlapped and reclassified using expert know ledge. Accordingly, quantitative computation is performed and the aided information is provided for the dec-ision of the monitoring netw ork layout of soil and water loss on the Loess Plateau in China. Af ter the existed mon-itoring stations are fully considered, 138 new stations are laid by combining the first level control stations with second level local control stations under national regulations and specificat ions on the arrangement of monitoring stations of soil and water loss.

Abstract:Treatment of unstable rock should be based on a detailed analysis and investigation of its surrounding conditions of geology.Unstable rock should be controlled wi th effective methods so as to ensure stability and reinforce drainage and monitoring.After the analysis for surrounding conditions of a unstable rock in Chongqing City, the measures such as cleanup, support, drainage, filling and g routing, are successfully adopted in treatment of unstable rock.

Abstract:The Ebinur Lake Oasis is located in the north of Xinjiang Wei Autonous Region, the west of Gurbantonggut desert. It is one of the most important agricultural regions and cotton bases in Xinjiang. Based on visualinterpretation of MSS, TM and ETM digital images in 1972, 1990 and 2001, a classification map and a landuse conversion mat rix are obtained by human-machine interaction classification, and dynamic change of the oasis in recent 30 years is studied. The result shows that both appearance characters and dist ribution area of the oasis have changed greatly, and the oasis area has been enlarged. Especially during the 11 years from 1990 to 2001, the oasis changed much more obviously than previous time. With the expansion of oasis, it has been also conf ronted with some ecological and environmental problems at the same time, i.e., the balance of primary nature is dest royed,and the confliction between desertification and oasis is protruded more obviously.

Abstract:The study area is located in the center of Dalate County. Based on 3S techniques and combined with ground investigation, the Land-sat TM images of 1987, 1995, 2000 and 2003 were interpreted. The changes of sandy land were analy zed by using the database of desertification dynamics from 1987 to 2003. RS and GIS softwares, such as Erdas 8.6, ArcView 3.3 and ArcInfo 7.1 were used as an interpretation tool. The cumulative impact analysis was used to find the reasons of desertification. Results showed that in the past 20 years, the desert-if ied lands were in the status of the reverse-development-reverse. The degree of dynamic desertification was the highest from 1995 to 2000. The analyses of natural elements and human activities with sliding average indicated that the cumulat impacts of population and livestock on desertification were signif icant, and the effect of population was strong er than livestock. the cumulative impacts of annual mean wind were always significant in all temporal scales. The effect of annual mean temperature was significant (at 0.01 scale) over two years.

Abstract:This study aimed to validate the agricultural drought indices derived from NOAA/AVHRR data and analyzed their uncertainties by taking Taigu County in Shanxi Province and Ji’ning County in Shandong Province for examples. The result from the analysis of relationships between drought indices and soil moisture in Taigu County shows that vegetation health index ( H), temperature condition index (T) and vegetation condition index (V) have somewhat low relations with soil moisture ( R2 is 0. 51, 0. 50, and 0. 56, respectively). Hand T have the closer relationship than normalized difference water index (W) and V. Validation using the data in J i’ning County shows that H, T and V have better relations with soil moisture (R2 is 0.97, 0.93, and 0.66, respectively). Whas a poor relation with soil moisture in the two cases. These suggest that the uncertainties in drought monitoring should be analyzed in terms of the crop planting pattern, monitoring time scale, vegetation condition and farming activity.

Abstract:Landuses and spatial landscape patterns of Qinghai Province in the Yellow River Basin in the year of 2001 are analyzed based on the technology of GIS and RS and using software of FRAGSTAT.An index of landscape resilience is further proposed to analyze the stability of landscape ecosy stem in the studied region.Results obtained show that the studied region is mainly covered with grassland, and it's landscape is complex and unstable, but has no obvious fragmentation.The diversity and landscape resilience indices of the headwaters of the Yellow River are lower than those of other counties, w hereas the diversity, equality and landscape resilience indices of the main stream of the Yellow River are higher than those of other counties in the studied region.In addition, the fragmentation of Xi' ning City is higher, whereas the landscape resilience index is lower than that of other counties in the studied regions, indicating that the Xining City meets with relative higher human disturbance than others.

Abstract:Aiming to study slope collapse in Guanqiao-Longmen (Anxi), Hetian (Changting), Dapu-Penghu (Yongchun) and Guanpo (Zhaoan), Fujian Province, this paper discusses geologic and geomorphologic background for slope collapse erosion based on rock characteristics, geological structure and history of geology. Results show that in the areas over which slope collapse is most widely dist ributed, rock is characterized by neat int ruded rock (granite) in the later period of Yanshan, which is located in the regional rift zone being active from the Paleozoic Era. The developed landform is in a phase from late mature stage to old stage. Altitude and relative eroded datum plane jointly affect the development of slope collapse, and slope collapse mainly takes place in the areas where relative height is 20～100 m.

Abstract:The domain, advancement s and existed problems of research on vulnerability in the field of resources and environmental science are concluded. It is believed that research on vulnerability is weak in aspect of water resource, especially surface water resource in South China. After reviewing research on vulnerability in the field of resources and environmental science, a concept of vulnerability of surface water reflecting the characteristics of surface water resource system is put forward for the first time. Then the meaning and cont ributing factors about vulnerability of ground water are analyzed. It is believed that vulnerability of ground water includes two aspect s of water quality and quantity, which all can decompose as natural vulnerability, artificial vulnerability and burdening vulnerability. A multipurpose index system is built to express the vulnerability of ground water resource. A quantitative assessment method is brought forward in the end.

Abstract:Based on the investigation to farm households in Yujiang County, J iangxi Province, the mechanism of farm household’s soil and water conservation investment behavior ( FHWSCIB) is analyzed. The factors which mostly influence the FHWSCIB are the multi-operation behavior of farm household, habit of manufacture, the scale management of agricultural land, the status of agricultural labor, soil and water loss disaster and economic condition of a family. In order to analyze the relativity between the FHWSCIB and these indeice, a multi2linear regression model is established. It turns out that the FHWSCIB is mostly influenced by the proportion of non-agriculture income, the time spent on farm, agriculture population, area under cultivation, soil and water loss disaster, average income and the distance f rom county to city. Farm households who have a great proportion of non-agriculture income have a less enthusiasm for soil and water conservation investment,while those who have more agricultural labors or whose members are more indust rious have more soil and water conservation input s. At last, some pieces of advice are presented on how to prompt the FHWSCIB and improve the status of soil and water loss.

Abstract:The implementation of thermal pow er project may induce a large amount of soil erosion in both construction period and operation period. As one of the major measures for soil erosion control, botanic measures can play agreat role in vegetation rehabilitation, soil erosion control and benef it accomplishment of soil and water conservation facilities. This paper makes a brief analysis of const ruction project characterist ics and the factors which have great influences on allocation of botanic measures, including features of project locat ion, layout of thermal power project, biological characteristics of plant and so on. It also analyses botanic measures in the third stage of the project by Shangdu Power Generation Co., Ltd. in Inner Mongolia. It is hoped that the study can afford some references for scient ific allocation of botanic measures, effect ive control of soil and w ater loss, improvement of environment and full demonst rat ion of the principle of ecological priority, comprehensive use and afforestation functions.

Abstract:This art icle aims to const ruct an evaluat ion index system of agriculture and ecology security in the loess hilly region using the index selecting principle which combines reg ional features with scientific foundation, integrality with relat ive independence, feasibility w ith operat ion, and comparison w ith pert inence. In order to present the evaluation index system w hich conforms to this area, the conceptual model of the/Pressure) Condition ) Response (PSR) is used with the ecological problems in the loess hilly reg ion considered. The index system includes the three parts of system pressure, system condition and system response, which is composed of 10 first-grade indexes and 21 second-grade indexes.

Abstract:An evaluation index system for the development level of water resources in Hu’nan Province is established through applying the grey relation analysis. By using the APH comprehensive evaluation method, the weight of each index is determined, and the development level of regional water resources is analyzed and evaluated. As a result, the comprehensive grade in most regions is less than 0. 6, and thus it can be concluded that the development level of regional water resources in Hu’nan Province is low. The study indicates that based on sustainable utilization of water resources, exploring and using the water resources in Hu’nan Province should adopt reasonable measures such as water saving, water preserving and st rengthened management.

Abstract:Based on the characteristics of current water resources in Yantai City, Shandong Province, the supporting capacity of water resources of thirteen individual dist ricts in the city is analyzed and evaluated using the index system consisting of seven indices in three categories of the amount of water resources and their ex ploitation, regional development and ecological environment. Results show that water resources are inconsistent with population, economy, arable land, ecological environment, and so on. So the supporting capacity of water resources is insufficient to regional development. Furthermore, there is a spatial difference in the support ing capacity of water resources.Water resources in the six districts of Laishan district, development area, Longkou City, Laizhou City,Zhaoyuan City and Changdao County are not matched with regional development, which indicates that the water resources have already rest ricted sustainable development of these dist ricts. Therefore, scientific management, reasonable utilizat ion and opt imized allocation are required to ensure the sustainable development of regional water resources in Yantai City.