A MATHEMATICAL MODEL OF SALMONID SPAWNING HABITAT1

ABSTRACT: A simulation model [Salmonid Spawning Analysis Model (SSAM)] was developed as a management tool to evaluate the relative impacts of stream sediment load and water temperature on salmonid egg survival. The model is useful for estimating acceptable sediment loads to spawning habitat that may result from upland development, such as logging and agriculture. Software in common use in the USA were adapted for use in gravel bedded rivers and linked to simulate water temperature (the USFWS Instream Water Temperature, SNTEMP model) and water and sediment routing (the USAE Scour and Deposition in Rivers and Reservoirs, HEC-6 model, version 3.2). These models drive the redd (spawning nest) model (the USDA-ABS Sediment Intrusion Dissolved Oxygen SIDO model) which simulates sediment intrusion and dissolved oxygen concentration in the redd environment. The SSAM model predictions of dissolved oxygen and water temperature compared favorably with field data from artificial redds containing hatchery chinook salmon eggs.     

Does intensity of change matter? Factors affecting adoption of agri-environmental schemes in Spain

Agri-environmental schemes (AES) are the main policy instrument currently available in the EU to promote environmentally-friendly farming practices. However, the rate of adoption of these measures is still relatively low in southern Europe, and understanding how these rates can be increased is still an open issue. The goal of this paper is to increase that understanding by testing whether the factors which determine AES sign-up decisions are influenced by the intensity of change in farming practices that are brought about by adopting the scheme. A micro-economic model reflecting farmer AES sign-up decisions is proposed and applied to two schemes in Spain respectively requiring major or minor intensity of change in practices by surveying farmers eligible for both schemes. The results show that farm structural factors play a role when major practice change is required by the scheme, yet when dealing with minor change, individual farmer characteristics play a more determining role. Social capital and farmer attitude are important factors in both the AES surveyed. Therefore, it may be concluded that improving agronomic design would be an important tool to improve farmer participation in AES where major change is involved, whereas improved targeting and extension would help uptake for AES involving a lesser degree of change.     

Review of Urban Stormwater Quality Models: Deterministic,Stochastic, and Hybrid Approaches1

Abstract: The growing impact of urban stormwater on surface‐water quality has illuminated the need for more accurate modeling of stormwater pollution. Water quality based regulation and the movement towards integrated urban water management place a similar demand for improved stormwater quality model predictions. The physical, chemical, and biological processes that affect stormwater quality need to be better understood and simulated, while acknowledging the costs and benefits that such complex modeling entails. This paper reviews three approaches to stormwater quality modeling: deterministic, stochastic, and hybrid. Six deterministic, three stochastic, and three hybrid models are reviewed in detail. Hybrid approaches show strong potential for reducing stormwater quality model prediction error and uncertainty. Improved stormwater quality models will have wide ranging benefits for combined sewer overflow management, total maximum daily load development, best management practice design, land use change impact assessment, water quality trading, and integrated modeling.     

国家环境保护模范城市现状分析及展望

改革开放以来,在我国经济快速发展的同时,产生了巨大的环境问题,为此,原国家环保总局审时度势,开展了创建国家环境保护模范城市的活动。本文对“创模”考核指标的调整情况进行概括,从总体情况、所属行政区、所属行政区级别、面积4个方面对目前“环保模范”城市状况进行了深入地分析,并对日后的“创模”工作进行了展望。     

高效油水分离器和过滤器处理油田污水的现场实验研究

为了开发高效、低耗的含油污水处理工艺技术和设备,在吉林油田新立采油厂,对石油大学（北京）研制开发的高效油水分离器和高效过滤器处理油田污水的技术性能进行了现场测试研究。油水分离器采用斜通道波纹板作内构件,过滤器用炉渣做滤料。现场实验表明：高效油水分离器和高效过滤器串联处理油田污水,不论污水含油量高低,其过滤器出口水中含油量不高于１０ｍｇ／Ｌ者达９４％：过滤器出口水中悬浮物不高于１０ｍｇ／Ｌ者占８６％。结果说明该套装置在油和悬浮物的脱除及操作方面性能优异。有推广应用前景。     

Modeling the relationships between land use and land cover on private lands in the Upper Midwest, USA

This paper presents an approach to modeling land-cover change as a function of land-use change. We argue that, in order to model the link between socio-economic change and changes in forest cover in a region that is experiencing residential and recreational development and agricultural abandonment, land-use and land-cover change need to be represented as separate processes. Forest-cover change is represented here using two transition probabilities that were calculated from Landsat imagery and that, taken together, describe a Markov transition matrix between forest and non-forest over a 10-year period. Using a three-date land-use data set, compiled and interpreted from digitized parcel boundaries, and scanned aerial photography for 136 sites (c. 2500 ha) sampled from the Upper Midwest, USA, we test functional relationships between forest-cover transition probabilities, standardized to represent changes over a decade, and land-use conditions and changes within sample sites. Regression models indicated that about 60% of the variation in the average forest-cover transition probabilities (i.e. from forest to non-forest and vice versa) can be predicted using three variables: amount of agricultural land use in a site; amount of developed land use; and the amount of area increasing in development. In further analysis, time lags were evaluated, showing that agricultural abandonment had a relatively strong time-lag effect but development did not. We demonstrate an approach to using forest-cover transition probabilities to develop spatially-constrained simulations of forest-cover change. Because the simulations are based on transition probabilities that are indexed to a particular time and place, the simulations are improved over previous applications of Markov transition models. This modeling approach can be used to predict forest-cover changes as a result of socio-economic change, by linking to models that predict land-use change on the basis of exogenous human-induced drivers.     

广州土壤中短链氯化石蜡的含量水平和分布特征

短链氯化石蜡(SCCPs)是一类新的持久性有机污染物(POPs),目前我国相关研究较少。为了解SCCPs在土壤中的污染现状和分布特征,测定了24个广州土样(含3个剖面采样点)中SCCPs的含量,分析了其同族体分布模式。结果表明:广州表层土壤中SCCPs的含量变化范围为6.8～541.2ng/g,均值为79.6ng/g;剖面土壤中SCCPs的含量范围为7.5～115.8ng/g,均值为33.1ng/g。不同类型土壤中SCCPs各同系物组分的分布模式相似,以碳原子数为10和11的Cl6-SCCPs/Cl7-SCCPs为主。     

衡水市空气主要污染物体积质量的时间分布特征

利用衡水市环境监测站2005—2007年度大气例行检测的数据,对衡水市大气中主要污染物SO^2、NO^2、PM10体积质量值的逐日数据进行统计分析,得出了衡水市空气污染的现状和时间变化规律：（1）污染物体积质量值的月变化曲线呈槽型分布,非取暖期的空气状况明显好于取暖期,取暖期SO^2平均体积质量是非取暖期的2．45倍;（2）污染物体积质量值的日变化曲线基本为两高两低型,其中取暖期污染指数早晨出现极高值的时间比非取暖期明显偏晚;（3）污染物体积质量值的年变化表明了SO^2的体积质量在降低,而NO^2的体积质量却有了小幅增长。