HYDROLOGIC LANDSCAPES ON THE DELMARVA PENINSULA PART 2: ESTIMATES OF BASE-FLOW NITROGEN LOAD TO CHESAPEAKE BAY1

ABSTRACT: Base-flow samples were collected from 47 sampling sites for four seasons from 1990–91 on the Delmarva Peninsula in Delaware and Maryland to relate stream chemistry to a “hydrologic landscape” and season. Two hydrologic landscapes were determined: (1) a well-drained landscape, characterized by a combination of a low percentage of forest cover, a low percentage of poorly drained soil, and elevated channel slope; and (2) poorly drained landscape, characterized by a combination of an elevated percentage of forest cover, an elevated percentage of poorly drained soil, and low channel slope. Concentrations of nitrogen were significantly related to the hydrologic landscape. Nitrogen concentrations tended to be higher in well-drained landscapes than in poorly drained ones. The highest instantaneous nitrogen yields occurred in well-drained landscapes during the winter. These yields were extrapolated over the part of the study area draining to Chesapeake Bay in order to provide a rough estimate of nitrogen load from base flow to the Bay and its estuarine tributaries. This estimate was compared to an estimate made by extrapolating from an existing long-term monitoring station. The load estimate from the stream survey data was 5 ± 10⁶ kg of N per year, which was about four times the estimate, made from the existing long-term monitoring station. The stream-survey estimate of base flow represents about 40 percent of the total nitrogen load that enters the Bay and estuarine tributaries from all sources in the study area.     

小流域地段景观生态设计研究——以大别山巴河上游地段为例

在实地调查研究的基础上，分析了巴河上游流域地段的景观结构功能与演替及流域治理存在的问题，切中流域生态环境变化的要害——水土流失问题。在区内景观带自然分异的基础上，进行了流域景观生态设计。     

Modeling Opportunity Costs of Conservation in Transitional Landscapes

Abstract:  Conservation scientists recognize the urgency of incorporating opportunity costs into conservation planning. Despite this, applications to date have been limited, perhaps partly because of the difficulty in determining costs in regions with limited data on land prices and ownership. We present methods for estimating opportunity costs of land preservation in landscapes or ecoregions that are a changing mix of agriculture and natural habitat. Our approach derives from the literature on estimating land values as opportunity costs of alternate land uses and takes advantage of general availability of necessary data, even in relatively data-poor regions. The methods integrate probabilities of habitat conversion with region-wide estimates of economic benefits from agricultural land uses and estimate land values with a discount rate to convert annual values into net present values. We applied our method in a landscape undergoing agricultural conversion in Paraguay. Our model of opportunity costs predicted an independent data set of land values and was consistent with implicit discount rates of 15–25%. Model-generated land values were strongly correlated with actual land values even after correcting for the effect of property size and proportion of property that was forested. We used the model to produce a map of opportunity costs and to estimate the costs of conserving forest within two proposed corridors in the landscape. This method can be applied to conservation planning in situations where natural habitat is currently being converted to market-oriented land uses. Incorporating not only biological attributes but also socioeconomic data can help in the design of efficient networks of protected areas that represent biodiversity at minimum costs.     

芦苇湿地运行过程中基质主要成分变化研究

在芦苇湿地净化景观水体中试试验中,对芦苇湿地基质中有机质、总磷、总氮含量变化进行跟踪检测分析和研究。结果表明,在芦苇湿地运行处理过程中,基质的厚度会逐渐增加;同时,基质中磷的含量有明显的增加趋势。基质中有机质和氮的含量未随着运行时间有显著性变化,但随着基质厚度的增加,基质沉降和吸附的有机质和氮的总量在逐渐增加。同时还研究了投加生物制剂对湿地运行效果及基质的影响,结果显示,投加生物制剂可以提高系统的处理效果,但对基质中有机质和氮的沉积动态平衡没有显著性影响。     

大山包湿地景观保护与开发的对策研究

针对大山包湿地的保护价值及其在黑颈鹤保护中的重要地位,提出了如何合理进行湿地景观的保护与开发,以确保湿地生态系统可持续性发展。     

景观水体的修复技术

针对目前景观水体存在的问题,本文简单介绍了水景水体的修复原则和方法。结合景观水治理工程的实例,分别从物理、化学和生物方法三个方面总结了景观水体的各种污染控制和管理措施,分析其优缺点及适用性。详述了水生植物、水生动物、微生物以及它们之间相互结合处理富营养化水体的修复技术。提出景观水体污染控制的关键是将污水处理的常规处理技术与生态处理技术有效结合。通过生物-生态技术的集成,全方位增加有益水质净化的水生生物,是富营养化水体生物-生态修复技术有效的强化手段。     

景观水体治理技术的研究

随着城市的日益发展,人们对城市环境的要求也日益提高,水景主题公园、水景建筑的不断涌现,对改善城市人居环境、提升城市形象有着重要的作用。但是近年来环境污染日益严重,常规水处理方法又不能简单地应用于景观水体的治理,人们对景观水体的治理也提出了迫切的要求。景观水体水质控制技术的研究,对营造与自然和谐的城市生态环境具有重要的作用。文章就目前对景观水体常用的物理、化学、生物及生态修复等各种方法进行了阐述,特别重点介绍了近年来新兴的人工湿地等生态修复处理方法。     

露天矿土地复垦综合预控研究

针对露天矿开采与土地复垦过程中遇到的综合技术问题,采用综合分析与模拟的方法,把露天矿开采工艺与土壤重构原理相结合,实现露天矿剥、采、排一体化工艺,优化排土顺序和位置,采集数据并建立采场和排土场DEM模型,同时对排土场覆盖的熟土进行定量计算,确定该区域的覆土量和平均覆土厚度,并对排土场生态重建进行三维景观模拟,实行排土场数字化管理,该技术使露天矿实现向精细、集中、数字化管理模式转变。     

污水处理厂绿化方式分析

以绿化常识为基础结合污水处理厂的特性,论述了污水处理厂厂区绿化的组成、栽植及布局特点。充分考虑污水处理厂特定功能环境:地下管网复杂、用地性质特殊和污染源的存在,阐述了合理的绿化布局方式,使绿化建设符合生产特点,体现厂区特色,具有良好的生态功能和观赏效果。     

基于DEM的白云山区域三维景观模型的建立和应用

数字高程模型DEM是对地形地貌的一种离散的数字表达,是构建三维模型的基础数据。DEM的一种数据格式GRID通过二维的格网灰度描述地形的起伏,另一种数据格式TIN通过连续三角面模拟地形表面。文章根据DEM对地形高程变化敏感这一特性,选取地形起伏大和地貌类型多样的山地丘陵地区—白云山区域作为研究区,在ARCGIS环境下将二维等高线数据转化为三维地形表面,以TIN为基准高程叠加区域内的矢量图层和遥感影像图,最终构建区域环境的三维景观模型.并以模型为基础,假设区域内的磨刀坑水库在无源淹没的情况下,应用三维分析功能计算水库淹没地形的表面积和体积。