Effects of streamline complexity on the relationships between urban land use and ecological communities in streams

Urban land use can adversely affect the water quality of adjacent streams through interactions at the edges of the two ecosystems. From a landscape ecological perspective, edges control the flow rate of materials between two adjacent systems. Based on the rationale that the streamline complexity formed between land uses and water bodies may function in this manner, we investigated the potential role of streamline complexity in the relationship between stream ecological communities and urban land use in Korea. Various indices of biological indicators including the diatom assemblage index for organic pollution, the trophic diatom index, the Korean saprobic index, and the index of biotic integrity were applied at 80 sampling sites in the Nakdong River system. We computed the fractal dimensions of the streamlines within 1-km buffers and the proportion of urban land use in the watershed within 5-km buffers around the sampling sites. A moderation model was adopted to investigate the role of streamline complexity in the relationship between urban land use and the biological indices of ecological communities. A comparison between a simple geometry regression model and complex geometry models indicated that streamline complexity may moderate the adverse impacts of urban land use on ecological communities in streams. The moderating effect of streamline complexity was particularly significant for assemblages of macroinvertebrates and fishes. Therefore, to enhance the ecological integrity of streams, we strongly recommend considering streamline complexity when restoring channelized streams in developed areas.     

Relationship between increment of groundwater level at the beginning of irrigation period and paddy filed area in the Tedori River Alluvial Fan Area, Japan

There are many paddy fields and large amounts of groundwater in the Tedori River Alluvial Fan in Ishikawa Prefecture, Japan. Water infiltration from paddy fields during irrigation may significantly contribute to groundwater recharge. Groundwater recharge is known to be one outcome of paddy farming, and in general is usually related to land use. However, a decreased area of paddy fields because of socioeconomic factors such as urbanization and increasing area of fallow fields has possibly affected the groundwater environment. Evaluation of the quantitative effect of paddy fields on groundwater is necessary for groundwater conservation. This study examined the relationship between differences in the depth of groundwater from just before the irrigation period to just after the first irrigation of paddy fields (increments of groundwater levels) in observation wells and the area of paddy fields around each well. The paddy areas within circular buffer zones, which were delineated at 0.2 km intervals between 0.2 and 2.0 km centered on each observation well, were calculated. A positive relationship was found between the rise in groundwater and the area of paddy field within different buffer zones at most wells. In addition, in the middle or upper part of the fan, the effect of changes in the area of paddy fields surrounding the well on the groundwater level rise was greater than that on the lower part of the fan.     

Influence of Habitat and Land Use on the Assemblages of Ephemeroptera,Plecoptera, and Trichoptera in Neotropical Streams

Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams.     

The effects of spatial variability of land use on stream water quality in a costal watershed

Researchers generally accept that land use types within a watershed closely relate with the water quality characteristics of streams. Despite numerous studies investigating the relationships between water quality and land use, there are increasing concerns about the geographical variation and lack of spatial integration in previous studies. We investigated the relationships between land use and water quality characteristics including biological oxygen demand (BOD₅), total nitrogen (TN), total phosphorus (TP), and Escherichia coli in the Wha-Ong estuarine reservoir watershed in Korea, which has spatially integrated land uses. Residential and paddy areas appear to be positively and negatively correlated, respectively, with degraded water quality. The spatial variations of these relationships were also examined using zonal analysis. Some results contrasted with those of previous studies that were conducted mostly in developed Western countries and may reflect the different land use intensities and agricultural practices in Korea. Relationships across zones, distinguished by distances from streams, were inconsistent and erratic, suggesting that the relationships between remote land uses and water quality may be affected more significantly by sub-basin characteristics than by the land use itself. The geographical differences and spatial variations found in this study indicate that caution must be taken in generalizing the relationship between land use and water quality.     

Logistic回归模型在 LUCC驱动力分析中的应用--以广东省清新县为例

利用田间大型土壤溶液渗滤装置,定位抽取不同母质土壤在20、60、100、200 cm处的土壤溶液,并对溶液中硝态氮浓度变化做连续测定,通过土壤溶液中硝态氮浓度随时间的变化,初步探讨不施肥条件下5种不同母质土壤硝态氮垂直向下运移特征。结果表明,不同母质土壤上硝态氮垂直运移的距离不同,在花岗岩、玄武岩发育的土壤上硝态氮有垂直移动到60 cm处的迹象,在片麻岩发育的土壤上硝态氮有垂直移动到100 cm处的迹象,在浅海沉积物、砂页岩发育的土壤上硝态氮有垂直运移到200 cm处的迹象。总体上来看,硝态氮在5种土壤20、60、100 cm处可移动的浓度含量存在差异,其多少顺序可基本概括为：砂页岩、片麻岩发育的土壤＞浅海沉积物、玄武岩发育的土壤＞花岗岩发育的土壤。     

2000～2014年闽东海岸带土地利用动态变化

海岸带地区因其特殊的海陆生态系统环境而成为土地利用/覆被变化(LUCC)研究的热点区域.本文以位于海峡西岸经济区东北翼的闽东海岸带作为研究对象,利用2000、2009和2014年3期Landsat TM/OLI影像作为数据源,对该区2000～2014年的土地利用动态变化特征进行分析.结果表明:研究区土地利用类型以林草地和耕地为主,其中林草地面积迅速扩增,研究期间共增加了1 047.24 km2,相比之下,耕地面积显著减少,近14a间共减少了959.45 km2;在人类活动影响下,水产养殖的动态变化最为剧烈,稳定性最差,而由于政府加强对建筑用地的集约利用,使其成为近14 a研究区最为稳定的土地利用类型,面积基本保持不变;闽东海岸带土地利用的集约化程度远超全国平均水平,土地利用程度综合指数达255.19,但2000～2009年间,研究区土地利用仍处于调整期,2009～2014年,随着经济的快速发展及前期的调整,土地利用效率有所提高,其变化量和变化率分别为4.86和0.019,土地利用步入发展期.本研究对闽东及其他地区的土地集约化利用及生态环境可持续具有指导意义.     

Assessment of Potato Dry Matter Concentration Using Short-Wave Near-Infrared Spectroscopy

The utility of short-wavelength near-infrared spectroscopy (over the wavelength region 750–950 nm), used in a partial transmittance optical geometry, was assessed as a means of estimating the dry matter concentration of potato tubers. The sampling optics did not involve contact with the sample, and could be used on a moving stream of product. A prediction accuracy of R ² (correlation coefficient of determination) of 0.85 with a root mean square error of prediction (RMSEP) of 1.52% for intact, whole tubers and R ² = 0.95 and RMSEP = 0.50% for sliced tubers was achieved. We conclude that short-wavelength near-infrared technology using a partial transmittance optical sampling geometry can be a useful tool for rapid assessment of tuber dry matter concentration prior to processing.     

A study on rational slopeland classification for land conservation in Taiwan: a case of Jhuoshuei River before Typhoon Morakot

Promulgated in 1976, “Slopeland Conservation and Utilization Act” aims to regulate the scope of slopelands. “Classification Standard of Slopeland Utilization Limitations” was set forth, classifying slopelands into lands suitable for agricultural, animal husbandry, or forestry purposes or as lands subject to strengthened conservation according to their average slope, soil effective depth, soil erosion degree, and parent rock. Overall inventory was carried out based on the said four factors to verify the classification standard of slopeland utilization limitations. However, the currently verified lands are mostly suitable for forestry or for agriculture and animal husbandry. Scattered placement of these lands results in critical issues such as segmented land use and impaired landscape and ecotype. Especially for lands verified as disaster-prone, they are immediately harmful to land conservation when typhoon or heavy rain occurs. Therefore, this study aims to research rational utilization of slopelands and use for land conservation in Taiwan. Jhuoshuei River is selected as the scope of the case study, using watersheds as analysis units. Seven vulnerability factors are selected, namely total curvature, average slope, average elevation, SPI, standard deviation of aspect, land use, and NDVI, in companion with a model of disaster susceptibility created based on logistic regression; this model interprets the success rate curve of disaster susceptibility and gives an area under the curve of up to 91.1 %. Subsequently, the diagram of disaster potential classification results of the Jhuoshuei River is created via cluster analysis.     

Simulation of water quality with the application of system dynamics model for population and land-use changes

Water quality is degraded due to urbanization because it causes population growth and land-use changes in a watershed. These changes are usually simulated using a linear equation; however, in reality, population and land use are very closely related. A watershed system dynamics model (WSD model) was developed in the simulation of the relation among population, land use (paddy fields, upland fields, forest, and household), and runoff. The model comprised of three sectors: the agricultural sector, nature sector, and urban sector. The elements in the WSD model were selected based on interviews with local government officers and references. The WSD model simulated population, land use, and runoff with an average relative error of about 5%. Total nitrogen (T-N) and total phosphorus (T-P) were simulated using the results of the WSD model and unit effluent loads. Field surveys were conducted to determine the rate of mitigation in paddy fields. In addition, correction equations for runoff and phosphate-containing detergent were introduced. The model simulated T-N with an average relative error of 9%, and T-P with 27%; a sensitivity analysis for the principal elements in the WSD model showed reasonable results.     

Quantification of the effect of rice paddy area changes on recharging groundwater

This study quantifies the effects of paddy irrigation water on groundwater recharge. A numerical model of groundwater flow was conducted using MODFLOW in a 600 ha study site in an alluvial plain along the Chikugo River, located in southwestern Japan. To specify the surface boundary condition, data on the land use condition stored in the GIS database were transferred into a numerical model of groundwater flow. The simulated results were consistent with the observed yearly changes of groundwater level. Thus, it was appropriate to use the model to simulate the effects of paddy irrigation on groundwater. To quantify these effects, the groundwater level was simulated during the irrigation period when all farmlands in the study site were ponded. In this situation, the groundwater level was 0.5 to 1.0 m higher, the ground water storage 20% larger, and the return flow of the groundwater to the river 50% larger than in the present land use condition.     

Long-term trends in intersectoral water allocation and crop water productivity in Zhanghe and Kaifeng,China

This paper examines the trends in water allocation among sectors, water use by source, cropped area, crop production and water productivity. The study was undertaken at two sites in China: the Zhanghe Irrigation District in the Yangtze River Basin approximately 200 km west of Wuhan and Kaifeng City Prefecture located just south of the Yellow River in Henan Province. In both areas, water demand for purposes other than irrigation has grown. In the Zhanghe Irrigation District this resulted in a sharp reduction of water availability for irrigation. The decline of water availability for irrigation resulted in adoption of water saving practices and policies that led to a significant gain in water productivity per unit of irrigation water. In the Kaifeng City Prefecture the increased demand from other uses was met by an increase in groundwater extraction without the dramatic cuts in supplies for agriculture as in the Zhanghe Irrigation District. Gains in water productivity were due almost exclusively to higher crop yields. There will be continuing pressure to further reduce diversions to agriculture from the Zhanghe main reservoir in the Zhanghe Irrigation District and from the Yellow River in Kaifeng. Research continues on testing practices that have the potential for further increasing water productivity, some of the results of which are reported in other papers in this volume.     

Analysis of runoff in the Han River basin by SSARR model considering agricultural water

This study begins to address the need for a runoff model that is able to simulate runoffs at control points in a dam’s upper and lower stream during the seasons of high and low water levels. We need to establish a synthetic management plan on water resources considering the runoff at the upper and lower streams to effectively manage the limited water resources in Korea. For this reason, we classified the Han River Basin into 24 sub-basins and arranged a great amount of rainfall data using 151 rainfall observation stations so as to prepare for the spatial distribution of precipitation. We chose several dams as subjects for this study, which includes the Chungju Regulating Reservoir, Soyang, Chungju, Hoengseong, Hwacheon, Chuncheon, Euiam, Cheongpyeong, and Paldang Dams as main controlling points. Also, we made up input data of this model, selecting the Streamflow Synthesis and Reservoir Regulation (SSARR) model as a runoff model in the Han River Basin. We performed a sensitivity analysis of parameters using hydrological data from the year 2002. And as a result, the findings of this study showed that, among many parameters related to the basin runoff, the following have revealed greater sensitivity than any other parameters: soil moisture index-runoff percent, baseflow infiltration index-baseflow percent, and surface-subsurface separation. On the basis of the above sensitivity analysis, we have used hydrological data between 2001 and 2002 when drafts and floods broke out in Korea to verify and calibrate the parameters of the SSARR model. Furthermore, we verified and calibrated the 2000 data using corrected parameters and performed an analysis of annual water balance in the Han River Basin from 1996 to 2005 considering agricultural water.     

Surface drainage nitrate loading estimate from agriculture fields and its relationship with landscape metrics in Tajan watershed

Pasture, forest, and farmland are the dominant land covers in the Tajan River watershed and this landscape status has a direct connection with nitrate pollution. Understanding the correlations between landscape variables and nitrate pollutant is a priority in order to assess pollutants loading and predicting the impact on surface water quality. The soil and water assessment tool was used to simulate nitrate loads in different land cover types in different years. The landscape pattern was calculated by FRAGSTATS. The contributing share of each land use/land cover shows nitrate pollutant produced by grassland (5.7%) and forest (29%) are less than those produced by agricultural land (64.2%). Agricultural land was identified as the main source of nitrate pollution. Paddy fields and orchards had the most intensive soluble nitrate loss especially in spring and summer. Statistical analysis indicated that nitrate was positively associated with patch density, edge density, patch number, total edge, effective mesh size, largest patch index, and landscape shape index (p ≤ 0.01). We then analyzed how nitrate was related to landscape attributes in six different sites. Also the regression analysis results suggested that landscape metrics could account for more than 94% of the variance of nitrate in the whole catchment. The regression models confirmed the great importance of the agriculture metrics and forest metric in predicting nitrate in watershed. Defining the generation and extent of pollution in this particular watershed which discharges into the Caspian Sea can constitute an important step toward protecting this ecosystem.     

Development of a water quality tank model classified by land use for nitrogen load reduction scenarios

Water quality in the watershed mainly used for agriculture is degraded by nutrients from fertilizers and animal wastes. These diffuse (non-point) sources have accumulated in soils and been released into the river system for the long-term. In this paper, a water quality tank model classified by land use is modified for the accumulation, and total nitrogen (T-N) is simulated over 40 years in the Yamada River basin within the Lake Kasumigaura watershed, Japan. For considering the nitrogen balance, the model has a database comprising statistical data such as population, land use, rain, fertilizer, and animal waste; it calculates cumulative load in soils and dissolved load separately. The model simulated the measured data with relative error of 15% for runoff and 7% for T-N. Five scenarios for the reduction of cumulative load were developed as a countermeasure plan: soil washing, slow-release fertilizer, fertilizer application reduction, cover crop, and animal waste reduction. The results show that T-N first decreases and then increases after 30 years in the case of the slow-release fertilizer scenario and that T-N is reduced by 30% after 40 years in the case of the 100% animal waste reduction scenario.     

Evaluation of land use change and groundwater use impact on stream drying phenomena using a grid-based continuous hydrologic model

The effect of land use change on drying streams was evaluated using a grid-based continuous hydrological model (PGA-CC). For a drying stream-progressed watershed (398.8 km²), the model was calibrated and validated using 7 years (2005–2011) of streamflow data at the watershed outlet with an average Nash–Sutcliffe model efficiency of 0.71. Based on the model simulation results for 36 years (1976 to 2011), both land use change and climate change decreased the 10-day minimum flow by 0.16 m³/s and increased the day counts below the annual average by 40.6 days/year. These changes resulted from the 8.7 % increase in urban area, 1.43-fold increase in groundwater use, and 1.1 °C temperature increase during the 36-year period. From the distributed results of the model, we identified the drying stream location and progression. The spring and winter seasons were relatively strongly affected, and drying streams were identified in more urbanized areas with greater groundwater use.     

珠三角九市都市农业产业竞争力评价

为衡量珠三角地区都市型农业的发展水平与竞争力，构建了珠三角都市农业产业竞争力指标体系，采用选择灰色关联度分析法，对珠三角9个城市的都市农业产业竞争力问题进行定量比较分析。研究结果表明：珠三角九市的都市农业竞争力由大到小依次为：佛山＞深圳＞珠海＞江门＞肇庆＞东莞＞深圳＞中山＞广州，各个指标中关联度最大的是相关与支持行业。从总体竞争力水平看，佛山、惠州和珠海在珠三角地区的排名靠前，说明这几个市的都市农业产业竞争力处于中上游水平，总体竞争力较强。     

Evaluation of HEC-HMS and WEPP for simulating watershed runoff using remote sensing and geographical information system

Although a variety of rainfall-runoff models are available, selection of a suitable rainfall-runoff model for a given watershed is essential to ensure efficient planning and management of watersheds. Such studies are relatively limited in developing nations, including India. In this study, rainfall-runoff modeling was carried out using HEC-HMS and WEPP hydrologic models, and remote sensing and GIS (geographical information system) techniques in the Upper Baitarani River basin of Eastern India using daily monsoon season (June–October) rainfall and the corresponding streamflow data of 6 years (1999–2005). Other input data such as soil map, land use/land cover map, and slope map were prepared using remote sensing and GIS techniques. The modeling results revealed that both the models under predict streamflow for 1999, 2002, 2004, and 2005 and over predict for 2001 and 2003, whereas HEC-HMS under predicts and WEPP over predicts streamflow for the year 2000. The percent deviation of total runoff volume simulated by HEC-HMS ranges between −2.55 and 31%, while it varies from −13.96 to 13.05% for the WEPP model which suggests that the WEPP model simulates annual flow volumes more accurately than the HEC-HMS model for most years. However, the lower values of root mean square error (RMSE) and RMSE-observation standard deviation ratio coupled with the higher values of Nash–Sutcliffe efficiency, percent deviation and coefficient of determination for HEC-HMS during calibration and validation periods indicated that the streamflow simulated by HEC-HMS is more reliable than that simulated by WEPP. Overall, it is concluded that the HEC-HMS model is superior to the WEPP model for simulating daily streamflow in the Baitarani River basin of Eastern India.     

海口美舍河沉积物化学性状时空分布特征

通过2018年4月和9月对海口市美舍河湿地上、中、下游底泥沉积物进行取样,研究沉积物化学性状的时空分布特征,并对重金属污染进行评价,以期为美舍河湿地公园的管理与湿地功能的维持提供科学依据。结果表明：（1）美舍河沉积物整体偏酸性,pH为6.58;4月份下游pH显著高于中游、上游Ⅰ和上游Ⅱ,而9月份各采样断面间无显著差异;9月份上游Ⅱ的pH显著高于4月份,增幅为13.0%,而9月份下游pH则显著低于4月份,降幅为16.6%。（2）4月份下游有机碳（SOC）含量显著高于其他采样断面,9月份上游Ⅰ和下游的SOC显著高于上游Ⅱ和中游,同时上游Ⅰ在两次采样间存在显著差异,9月份较4月份显著增加65.4%;（3）全氮（TN）和全磷（TP）含量以及重金属铜（Cu）、铅（Pb）和锌（Zn）含量整体上由上游至下游呈增加的趋势,其中中游TP含量和下游Cu含量在两次采样间存在显著差异,9月份TP含量较4月份显著增加76.9%,9月份Cu含量较4月份显著降低13.0%。（4）相关性分析结果表明,pH与Cu及Zn含量之间存在极显著正相关关系（P<0.01）,SOC、TN及TP含量与各重金属含量均呈极显著正相关关系（P<0.01）。综合分析沉积物的污染系数以及潜在风险发现,美舍河沉积物属清洁水平、较低潜在风险;同时,美舍河富营养化较轻,总体未受重大污染,具有较优质的环境,底泥符合农用标准;此外,需加强上游的污染源控制。     

Seasonal characteristics of surface water quality in the wastewater catchment system of an urbanizing basin

Vientiane, Lao PDR, has been subject to extensive and ongoing urbanization plans, including development of natural marshes and residentialization of paddy fields into suburban areas, despite natural marshes playing a vital role in treating wastewater from urban areas. Therefore, it is important to understand the current situation regarding the nutrient balance in these natural wastewater treatment systems to predict future conditions and design appropriate measures against water quality deterioration. However, limited data are available in Vientiane on the hydrological characteristics of water and nutrient runoff that flow into marshes through drainage canals. In this study, we conducted a periodic survey of drainage canals and Mak Hiao River in the wastewater catchment system surrounding Vientiane during the rainy and dry seasons. We monitored the discharge of surface water at 21 observation sites and analyzed water quality of nitrogen, phosphorus, and total organic carbon. These observations revealed that the concentrations of dissolved nitrogen and phosphorus were significantly higher at sites in urban areas, followed by sites in the main river basin and those in agricultural areas. Dissolved nitrogen and phosphorus concentrations varied with runoff discharge, especially in urban and river basin sites, with lower concentrations in the rainy season and higher concentrations in the dry season. On the other hand, we found no significant differences between the rainy and dry seasons in nutrient concentrations in the agricultural basin. Finally, we proposed measures to counteract the deterioration of water quality during dry seasons and simulated the impact of these measures.     

Multi-objective optimization of the coat-hanger die for melt-blowing process

In this paper, a multi-objective genetic algorithm based on the numerical simulation of the polymer flow is proposed to optimize the geometry parameters of the coat-hanger die with uniform outlet velocity and minimal residence time. The vector evaluated GA method is used to find the parameter values for obtaining the uniform outlet velocity and minimal residence time, where the manifold angle, the land height and the slot gap are chosen to be the design variables, the outlet velocity and the residence time are obtained by simulating the three-dimensional and isothermal polymer flow in the coat-hanger die. The stochastic universal sampling (SUS) is adopted to select the new population which is representative of a coat-hanger die. The optimal geometry parameters of the coat-hanger die achieved in the 30th generation among 20 individuals of each generation, which showed that the manifold angle and the gap slot were the most influencing design parameter on the coefficient of variation (CV) value of outlet velocity and residence time.