RIVER SYSTEM AND DISTURBANCE FACTORS IN THE LAKE TOBA

Situated at an elevation of 905 m above sea level in the Province of North Sumatra, Lake Toba and its surrounding landscapes are regarded as a natural heritage in a certain extent, as a quoted national treasure. Unfortunately degradation of the land and water resources in the watershed along Lake Toba is taking place at an alarming and totally unacceptable rate. The quality of the lake is partly depended on input the quality of the rivers. When compared to the control area the water quality that influenced by the piggeries are highly polluted. It can be concluded that the Salbe River at the downstream of the piggeries has been polluted and apparently it is a serious problem to the catchment area management. It should be noted that the polluted river would influence the water quality of the Lake Toba. Based on calculation, the permissible BOD5 according to B- river standard is 238 mg/L, it means the river still in B standard but the condition and quality are decreasing continuously. Following the Indonesian health standard the permissible BOD is - 461 mg/L. It means BOD in the river should be reduced 461 mg/L or clean program is needed.     

基于扫描矢量化地图数据生产的数据质量控制

概述了基于扫描矢量化GIS数据的生产过程 ,介绍了扫描矢量化质量控制的策略和方法 ,在地图扫描阶段采用栅格图纠正的方法对地图的变形进行纠正 ,以提高矢量化原图的质量 ,在基于扫描矢量化GIS数据的生产过程中 ,可从算法和软件使用工艺方面提高数据的质量     

Water Quality Impacts of Climate and Land Use Changes in Southeastern Pennsylvania*

This study investigates potential changes in nitrogen and phosphorus loads under a warmer and wetter climate, urban growth, and combined changes in the Conestoga River Basin and its five subbasins in southeastern Pennsylvania. A GIS‐based hydrochemical model was employed for assessing the sensitivity of the basins to the projected changes in 2030. Under the HadCM2 climate change scenario, mean annual nitrogen and phosphorus loads are expected to increase, with great increases in spring but slight decreases in fall primarily because of changes in monthly precipitation. When climate change and urbanization occur concurrently, mean annual nitrogen loads further increase by 50% in the most urbanizing subbasin. Point source nitrogen control could mitigate negative effects of climate and land use changes, reducing mean annual nitrogen loads to the contemporary baseline level.     

Study of statistically correcting model CMAQ-MOS for forecasting regional air quality

Based on analysis of the air pollution observational data at 8 observation sites in Beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution emission inventory and improves the forecast level of air quality. Also this work employed a way of combining point and area forecasting, i.e. taking the products of CMAQ for a center site to forecast air pollution for other sites in vicinity with the scheme of model products "reanalysis" and average over the "area".     

Use of time series analysis for the identification of tidal effect on groundwater in the coastal area of Kimje, Korea

The purpose of this study is to apply time series analysis to investigate whether the groundwater quality in the coastal area is affected by the tide. Continuous and regular in situ monitoring data of electrical conductivity (EC) and groundwater level, and tidal level data measured by the National Oceanographic Research Institute were used for the time series analysis. Through the time series analysis, it is known that EC and groundwater level conspicuously fluctuate with two periodicities (15.4 and 0.52-day), which is very similar to those of the tide. Also the behaviors of their fluctuations vary in accordance with the tidal period. These indicate that the groundwater quality has been mainly controlled by the tidal level, and the strength of tidal effect on the groundwater quality is different according to the tidal period.     

施工降水中的环境保护及水资源合理利用

城市缺水是目前带有普遍性的重大问题 ,但在城市建设过程中 ,宝贵的地下水资源遭到浪费的现象又大量存在 ,解决好施工降水与环境保护问题是关系到城市发展的重要问题之一 ,结合郑州市的工程实践 ,谈谈施工降水中的环境保护及水资源合理利用问题。     

宁东煤田枣泉矿井综合物探效果

为探明宁东煤田枣泉矿井首采区煤层自然范围及充水性，根据采区内地球物理物征，采用高精度磁法，直流电测深法和激发极化法进行综合勘探。在磁法勘探中结合测区曲线特征，建立数据体模型，正演计算烧变岩边界；电法勘探利用烧变岩含水后电阻率降低的特征确定其含水范围及富水性。     

Development of an integrated conceptual model for the rational management of the transboundary Nestos River, Greece

This paper provides a detailed analysis of the geologic, hydrologic and hydrogeologic characteristics of Nestos River basin, which is formed within the Greek mountainous part of the river. The quantitative analysis was mainly based on the data of the river flow in different gauging points across the rivercourse as well as on the data of groundwater discharge from karst springs of the mountainous area while important conclusions were made regarding the hydraulic connection between the surface waters of the river and the groundwater of the karst aquifers of the basin. The qualitative analysis has shown that the quality of both surface waters and groundwaters of the investigated basin is high, whereas, no sources of contamination were indicated during this research. The possible effects of the two large dams of Platanovrisi and Thesavros are also analysed as they strongly affect the quantitative and qualitative regime of the river delta.     

极端洪水导致的湖泊水位抬升和氮磷输入增加对苦草(Vallisneria natans)的复合影响

据全球气候变化模型预测,未来极端洪水事件将呈现增多和加剧态势。极端洪水对沉水植物功能性状、生长发育状况及整个生态系统均有深远的影响,研究极端洪水对沉水植物生长发育的影响对理解和预测气候变化过程中水生态系统的变化具有重要意义。本文针对极端洪水事件引起的水位急剧上升和营养负荷量增加双重效应,在实验周期90 d内设置对照(水位保持75 cm)、2种极端洪水条件(水位在第1天从75 cm快速上升至150 cm + NP输入、水位从75 cm逐步上升至150 cm + NP输入)以及水位保持75 cm + NP输入4项处理(后3项处理中营养输入总量相同),研究了极端洪水对沉水植物苦草(Vallisneria natans)生长、繁殖对策及生物量分配的影响,实验过程中还同步监测了浮游植物、附着藻类和水体营养状况(TN和TP)。在苦草的17个测定指标中,只有根生物量分配和有性繁殖分配在4个处理下无明显变化。从水位的单独作用看,相对于营养增加且水位恒定的处理,两种洪水条件(水位急剧上升和逐步上升)均降低了苦草的分株数、叶片数、间隔子数、间隔子总长、最大根长、花果数以及各器官生物量和总生物量,促进了人工基质表面附着藻类的生长。水位急剧上升时,植株对间隔子的生物量投资倾向于最小,而株高和植株对叶的生物量投资倾向于最大。从营养负荷的单独作用来看,相对于对照组,营养增加且水位恒定的处理中水体N浓度显著增加,促进浮游植物和苦草表面附着藻类的生长,但是从二者的Chl.a浓度来看,浮游植物遮光作用相对较大,抑制了苦草叶、根和间隔子的生长,但有性繁殖生物量无明显变化。从水位和营养负荷联合作用的模式来看,水位上升和营养负荷两个环境因素的联合作用会使入湖营养负荷加强水位上升对沉水植物生长的影响效应,二者的联合作用使叶、根、间隔子和有性繁殖生物量均大大降低。因此,极端洪水对沉水植物的不利影响较大,一方面水位抬升会直接影响沉水植物,另一方面会通过浮游植物间接影响沉水植物生长发育。     

三峡库区重庆段水土流失的时空格局特征

在TM 解译的三峡库区重庆段1999 年和2004 年水土流失数据及相关辅助数据的支持下, 借助GIS 技术, 分析了研究区5 年来水土流失的时空演变及地理空间分异特征与规律。 研究结果表明: (1) 研究区水土流失总体呈现好转趋势, 极强度和剧烈水土流失面积下降变幅最大。(2) 水土流失主要分布在紫色土、黄壤、石灰(岩) 土、水稻土和黄棕壤分布区。(3) 水 土流失主要发生在受人类活动影响最为剧烈的旱坡地和疏林地。(4) 水土流失表现出明显的垂直分异特征, 主要集中于高程200~1500 m 的低山、丘陵地区。(5) 水土流失与坡度具有很好的相关性, 主要分布在15^o以上的陡坡地。(6) 水土流失与坡向分异无明显的相关关系。各坡向水土流失面积和强度分布基本相当。(7) 水土流失主要集中在300~320 和320~340 j.cm/hm². h 的降雨侵蚀力(R) 值分布区。剧烈水土流失与高降雨侵蚀力具有较好的对应关系。