论煤矿城市塌陷区和露天采矿区的生态重建战略问题

本文对上述不同地区煤矿塌陷区和露天采矿区的生态重建战略问题分别进行了论述。     

CHANNEL MORPHOLOGY EVOLUTION AND OVERBANK FLOW IN THE GEORGIA PIEDMONT1

ABSTRACT: Historic changes in stream channel morphology were investigated in the Georgia Piedmont to better understand the hydrologic processes and functioning of the region's riverine systems. USGS gaging station data and channel geomorphology data were collected from thirty study sites in the Upper Oconee River Basin for flood frequency analysis. Historic and modern (i.e., present-day) channel capacity discharge (i.e., overbank flow) was calculated using Manning's equation and historic channel cross-section records. The recurrence interval for overbank flow was estimated for each site from flood frequency data. Results indicate that channel expansion has occurred throughout the basin, especially in upper reaches. Recurrence intervals for modern overbank events were variable and generally high ranging from < 2 to > 500 years for first to third order streams. They were less variable and lower for fourth and fifth order streams, ranging from < 2 to 3 years. Potential depositional thresholds were identified that exemplify the complex response of sediment distribution patterns throughout the basin. Results indicate overbank flows occur less frequently now than they once did due to historic accelerated sedimentation and subsequent channel expansion. One application of these findings is that these basin processes are likely applicable across the region and may impact the hydrologic functioning of associated Piedmont riverine wetlands that depend on flooding regimes.     

新型防粘闭污水土地处理系统的研究与应用

对新型污水土地处理系统进行了研究 ,并详细分析了该系统具有较好处理效果且不发生堵塞的原因 ,总结了该系统的优缺点     

地下水漏斗区农户冬小麦休耕意愿的影响因素及其生态补偿标准研究——以河北衡水为例

近年来,国家大力提倡耕地休养生息,推行土地休耕制度,以提高地力,保障农业可持续发展。由于水资源短缺已经成为制约我国华北地区经济社会发展的重要因素。华北地下水漏斗区作为土地休耕的三个试点之一,主要目标是退耕高耗水的冬小麦,实现“一季休耕、一季雨养”,以减少地下水用量,修复地下水环境。农户作为农村最主要的生产与经营主体,如何给予农户合理的补偿,使其有效地实施冬小麦休耕政策成为缓解华北地区水资源短缺的关键因素。论文运用问卷调查法、机会成本法与Logistic模型对意愿与补偿标准进行分析,探讨了河北衡水地下水漏斗区农户冬小麦休耕意愿的主要影响因素及其生态补偿标准的合理性,以便为我国科学合理地制定地下水漏斗区耕地轮作休耕政策提供理论依据。研究结果表明：1）农户的文化程度、家庭农业劳动力总数、抚养比、农户对地下水漏斗区冬小麦休耕态度、农户对政府实行政策的信任度与农户休耕意愿呈显著的正向影响;2）务农工日、耕地质量、人均耕地面积与农户休耕意愿呈显著的负向影响;3）只考虑冬小麦对地下水影响,不考虑农产品市场价格变化的影响,建议河北衡水地区休耕农户补偿标准为518元/亩（7 770元/hm²）。最后论文提出了因地制宜地制定地下水漏斗区冬小麦休耕的补偿政策,发展绿色产业,转移剩余劳动力,并做好休耕政策宣传力度等政策建议。     

生态土壤深度处理系统启动周期的研究

采用室内模拟试验装置,在2种实际工程用土和2种水力负荷条件下,考察了生态土壤深度处理系统对生活污水主要污染指标的去除效果及其各自的启动周期;同时对整个系统的启动周期的判断以及同类生态工艺的启动周期的判断方法做了初步探讨。研究结果表明:生态土壤深度处理系统的TP,CODCr和氨氮的去除启动周期分别为15～20,23～34和32～37d,系统的启动周期为37d左右。该系统属于非均匀混合型、多生态层次的生态处理工艺,其反应机理包括物理化学吸附作用、微生物生化作用和生态效应3类。启动周期完成的判断原则为:物理化学吸附作用是生化过程的结束;微生物生化作用是达到相应出水标准后稳定1周;高等植物的生态效应可以忽略,微生物生态系建立和稳定后的生态效应则视出水稳定达标情况而定,出水水质波动但达标的情况,即认为完成;反之,则达标稳定1周即认为完成。      

甘肃中部地区生态安全评价

在PSR模型框架下，利用熵法确定权重，采用1986年Landsat TM和2000年ETM＋影像确定模型中的自然组分数据，结合社会经济统计数据，对生态安全过程进行景观格局判定，较好地得出了15年来甘肃中部地区生态安全的变化状况。研究表明：2000年甘肃中部地区生态安全状况整体较差，15年来，人类活动加速了自然组分的退化，逐步弱化了景观中的稳定成分，促进形成了异质性程度低、格局粗粒化、稳定性差的景观格局，其中，快速城市化、水资源减少和耕地、林地等重要土地资源的快速转化是整个地区生态安全状态弱化的主要原因。     

我国北方风沙灾害加剧的成因及其发展趋势

综合分析了我国风沙灾害加剧的原因,并从我国北方沙漠、沙地形成演变的地理格局,探讨了我国沙化过程的中、长期发展趋势。本文认为,我国近年风沙灾害的加剧是在气候趋于干燥化背景下,人类大面积发展沙区生产的结果,但是,目前的流沙分布范围仍不及末次冰期极盛时期。未来我国风沙灾害的发展主要取决于气候增温背景下降水的时空分布、沙区的风化变化与地表土地的利用格局。     

地下水开采引起地面沉降预测方法的现状与未来

地面沉降作为一种广泛的地质灾害,不仅对地面设施造成很大的破坏作用,而且也会使地下环境发生变化,给工业生产、城市建设和人们生活带来的影响是深刻和巨大的。本文首先分析了地下水开采引起地面沉降的机理;然后根据运用的理论将目前由于地下流体资源开发引起地面沉降的预测方法归纳为5种:数理统计法、早期的数值计算法、准三维计算法、基于真三维水流模型的计算法及三维完全耦合模型,并将之分类总结,概括其优缺点。重点介绍了当前运用最多的准三维预测方法,以及1种基于真三维水流模型的计算方法,该方法曾经成功地分析了日本房总半岛由于地下水抽取引起的地面沉降。     

Dynamic Changes of Sandy Land in Northwest of Beijing, China

The area northwest of Beijing is one of the most important regions where many organizations invest and pay most attention. The environmental problems in this region affect not only Beijing but also the surrounding area. Based on observation of the characteristics of the change in sandy land, this study classified four types of dynamic change of sandy land, including extended sandy land, the reversely changed sandy land, the potential sandy land and no change in sandy land. Then the process and the trend of changes in sandy land and their environmental impact on the area northwest of Beijing were analyzed. The results show that the area of sandy land has increased in this region in the period of 1991 to 2002. Change between sandy land and grassland was the dominant change. It is found that the monitoring zones of Hunshandake sandy land and north of Yin Shan are regions with high ratio of extended sandy land, and are connected with widespread potential change of sandy land. This implies that these two regions have a high probability of increase in sandy land in the future. On the other hand, in the monitoring zone of Horqin sandy land and Ba Shang Plateau and its surrounding area, desertification had been controlled and the area of sandy land is expected to decrease. This indicates that the direction of the sandstorm to Beijing is expected to gradually move to the northwest. Furthermore, the decreases in sandy land and the reversing change from arable land to grassland and forests in the study region will affect the land quality and atmosphere. And the logistic multiple regression (LMR) model was employed to better understand the complexity and processes of increases in sandy land. This model predicts that there is a high probability of increases in sandy land in north of Siziwang Banner, Zhengxiangbai Banner and Zhenglan Banner. Finally, suggestions to the ecological construction of the study area have been proposed.     

Spatial Variability of Soil Organic Carbon in Relation to Environmental Factors of a Typical Small Watershed in the Black Soil Region, Northeast China

A total of 292 soil samples were taken from surface soil (0–20 cm) of a typical small watershed–Tongshuang in the black soil region of Heilongjiang province, northeast China in June 2005 for examining the concentration of soil organic carbon (SOC). Spatial variability of SOC in relation to topography and land use was evaluated using classical statistics, geostatistics and geographic information system (GIS) analyses. The objective of this study was to provide a scientific basis for land management targeting at improving soil quality in this region. Classical statistical analysis results indicated that the variability of SOC was moderate (C _V = 0.30). Slope position and land use types were discriminating factors for its spatial variability. Geostatistics analyses showed that SOC had a strong spatial autocorrelation, which was mainly induced by structural factors. Mean concentration of SOC in surface soil was 2.27% in this watershed, which was a very low level in the northern black soil region of northeast China. In this small watershed, present soil and water conservation measures played an important role in controlling soil loss. But SOC's restoration was unsatisfactory. Nearly three-quarters of the area had worrisome productivity. How to improve SOC concentration targeting at soil fertility is a pressing need in the future.