ANALYZING CORRELATIONS BETWEEN STREAM AND WATERSHED ATTRIBUTES1

ABSTRACT: Bivariate correlation analysis has been widely used to explore relationships between stream and watershed attributes that have all been measured on the same set of watersheds or sampling locations. Researchers routinely test H₀: ρ= 0 for each correlation in a large table and then go on to discuss only those that are declared “significant.” Such test results are inaccurate because no allowance is made for multiple testing, and also because the tests are not mutually independent. This paper reviews the Bonferroni approach to controlling the overall error rate in multiple testing and shows how the approach becomes impractical for large correlation tables. The Hotelling/Williams test is introduced for comparing two dependent correlations that share a variable, and numerical constraints for two such correlations are illustrated. References are also given for testing other hypothesized patterns among dependent correlations, and links to dependent correlation software are provided. The methods are illustrated for watershed and stream variables sampled in 23 small agricultural watersheds of the Willamette Valley, Oregon.     

SEDIMENT OXYGEN DEMAND IN THE ARROYO COLORADO RIVER1

ABSTRACT: The lower reaches of the Arroyo Colorado have historically failed to meet their use under subsection 303(b) of the U.S. Clean Water Act due to fecal coliform bacteria and low dissolved oxygen (DO). Fish kills, especially at the tidal confluence at the Port of Harlingen, Texas, have been reported. Oxygen demand from sediment (SOD) for a river typically has two states‐diffusion limited SOD (SOD) and potential SOD (pSOD), expressed when sediment is resuspended through increased flow or other disturbances. The objective of this research was to measure SOD in the Arroyo Colorado River in situ, estimate pSOD ex situ, and evaluate the relationship between SOD and the depositional environment. We measured SOD and pSOD in the Arroyo Colorado River at up to eight sites over three sampling events. We identified the sample sites based on a modified Rosgen geomorphic index for streambed stabilization. Sites with high sediment deposition potential had high SOD. The average values of SOD between sites were 0.62 g/m²/day (standard deviation 0.38 g/m²/day) and ranged from 0.13 to 1.2 g/m²/day. Potential SOD values ranged from as low as 19.2 to as high as 2,779 g/m³ sediment/ day. Potential SOD can serve as an indicator of the possible impact of SOD from resuspended sediment in stream systems.     

COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING1

ABSTRACT: Discrete cold water patches within the surface waters of summer warm streams afford potential thermal refuge for cold water fishes during periods of heat stress. This analysis focused on reach scale heterogeneity in water temperatures as influenced by local influx of cooler subsurface waters. Using field thermal probes and recording thermistors, we identified and characterized cold water patches (at least 3°C colder than ambient streamflow temperatures) potentially serving as thermal refugia for cold water fishes. Among 37 study sites within alluvial valleys of the Grande Ronde basin in northeastern Oregon, we identified cold water patches associated with side channels, alcoves, lateral seeps, and floodplain spring brooks. These types differed with regard to within floodplain position, area, spatial thermal range, substrate, and availability of cover for fish. Experimental shading cooled daily maximum temperatures of surface waters within cold water patches 2 to 4°C, indicating a strong influence of riparian vegetation on the expression of cold water patch thermal characteristics. Strong vertical temperature gradients associated with heating of surface layers of cold water patches exposed to solar radiation, superimposed upon vertical gradients in dissolved oxygen, can partially restrict suitable refuge volumes for stream salmonids within cold water patches.     

基于多媒体技术的<中国自然灾害>教育软件开发

根据社会公众对中国自然灾害信息的需求，开发了《中国自然灾害》多媒体教育软件。软件以区域灾害系统理论为指导，设计了内容框架、基本体系。通过声音、影像、动画和文本等媒体形式可向社会深层次、多角度地介绍中国自然灾害信息，普及减灾知识，增强社会防灾减灾意识。     

利用天然资源开发食用色素

介绍了天然食用色素的新品种、制备方法、纯化方法和改性研究的进展，分析了天然食用色素的发展趋势。     

SOUND POLICY OR SMOKE AND MIRRORS: DOES ECOSYSTEM MANAGEMENT MAKE SENSE?1

ABSTRACT: Protection of ecosystems as entities on the landscape has attracted a wide range of support. Ecosystem-based public policies are claimed to be more effective, efficient, and scientifically sound than other approaches to environmental and natural resource policy. The ecosystem concept was never intended to serve as a public policy guide or to determine landscape units for land management purposes. This paper critically examines the use of the ecosystem concept in public policy and land use management and analyzes the proposed rule to manage the National Forest System according to ecosystem management principles. The concept is found to be unsuitable as a basis for guiding environmental and natural resource public policies in general while the proposed rule to manage the national forests according to ecosystem management principles is shown to be incoherent.     

TEMPORAL AND GEOMORPHIC VARIATIONS OF STREAM STABILITY AND MORPHOLOGY: MAHOGANY CREEK,NEVADA1

ABSTRACT: Detailed studies of long-term management impacts on rangeland streams are few because of the cost of obtaining detailed data replicated in time. This study uses government agency aquatic habitat, stream morphologic, and ocular stability data to assess land management impacts over four years on three stream reaches of an important rangeland watershed in northwestern Nevada. Aquatic habitat improved as riparian vegetation reestablished itself with decreased and better controlled livestock grazing. However, sediment from livestock disturbances and road crossings and very low stream flows limited the rate of change. Stream type limited the change of pool variables and width/depth ratio, which are linked to gradient and entrenchment. Coarse woody debris removal due to previous management limited pool recovery. Various critical-element ocular stability estimates represented changes with time and differences among reaches very well. Ocular stability variables tracked the quantitative habitat and morphologic variables well enough to recommend that ocular surveys be used to monitor changes with time between more intensive aquatic surveys.     

UNCERTAINTY IN ESTIMATING BANKFULL CONDITIONS1

ABSTRACT: Bankfull depth and discharge are basic input parameters to stream planform, stream restoration, and highway crossing designs, as well as to the development of hydraulic geometry relationships and the classification of streams. Unfortunately, there are a wide variety of definitions for bankfull that provide a range of values, and the actual selection of bankfull is subjective. In this paper, the relative uncertainty in determining the bankfull depth and discharge is quantified, first by examining the variability in the estimates of bankfull and second by using fuzzy numbers to describe bankfull depth. Fuzzy numbers are used to incorporate uncertainty due to vagueness in the definition of bankfull and subjectivity in the selection of bankfull. Examples are provided that demonstrate the use of a fuzzy bankfull depth in sediment trans. port and in stream classification. Using fuzzy numbers to describe bankfull depth rather than a deterministic value allows the engineer to base designs and decisions on a range of possible values and associated degrees of belief that the bankfull depths take on each value in that range.     

河南省综合自然景观旅游资源的区际比较研究

针对目前河南省综合自然景观旅游资源区域整体优劣定量评价不足的情况，选取了国家重点风景名胜区、国家水利风景区、国家自然保护区、国家森林公园和国家地质公园5类综合自然景观类旅游资源，采用绝对数量、地均数量、人均数量3种评价指标和定量分析方法，对河南省18个省辖市的综合自然景观旅游资源进行了比较，阐述了河南省综合自然景观旅游资源空间分布的基本状况和旅游资源的区域发展重点。