SEISMIC REFRACTION ANALYSIS OF WATERSHED MANTLE RELATED TO SOIL,GEOLOGY AND HYDROLOGY1

ABSTRACT: An extensive hammer seismic refraction survey was carried out in three contiguous watersheds (217, 89, and 190 acres) on a laccolith near Sturgis, South Dakota to test its utility in rugged mountain terrain. Isopachs (lines connecting points of equal mantle thickness), area-elevation curves (hypsometry), and structure contours were used together with drill cores, petrography, hydrographs, and soil information to interpret the nature and role of porous mantle in the waterflow behavior of the watersheds. Refraction profiles produced only one geologically meaningful seismic contrast within the loccolith. Drill cores indicated a shallow stony profile on a sheeted horizon terminating on isotropic crystalline rock impervious except for tight joints. Means of refraction and core interpretations were not statistically different. Apparent seismic discontinuities deeper within the bedrock lacked geological identity. Storm hydrographs and water yields are better related to soil type differences and porous mantle distribution than to average porous mantle depth. On the other hand, slope of flow-duration curves correlate with average porous mantle depth. Porous mantle isopachs also indicate that measured flow from each basin is total area flow. Thus, porous mantle isopachs and hypsometry, and soil type delineation are complimentary in our interpretation of watershed behavior.     

一种导电混凝土的制备及其电阻率测量

本文综述了导电混凝土的发展以及应用情况,提出了用导电混凝土作为接地材料的设想,并选择氧化铁粉作为骨料,添加适量碳粉配制了一种导电混凝土来验证。通过改变不同的配比制作导电混凝土模型,用四电极法测量其电阻率,得出碳粉比例对其电阻率的影响。     

面向新时期流域管理的控制单元划分方法设计与应用

科学划分控制单元是实现流域水环境精准、高效管理的重要基础。为满足新时期中国流域系统治理和“三水”统筹的新要求、新任务,设计建立了一种新的控制单元划分技术方法,将中国重点流域划分为3442个断面控制单元和822个流域控制单元。基于控制单元划分成果,进一步构建了包含流域—流域控制单元—断面控制单元—控制断面—水功能区5个层级逐步细化的流域空间管控体系。实际案例分析与论证表明,新的流域空间管控体系能有效促进流域水环境管理各项措施落地,可进一步推动流域治理科学化、精细化、差异化,并为“三水”统筹提供决策支持。     

流域环境司法机制的发展：从环境法庭到环境法院

为促进流域的司法保护,我国一些地方法院成立了专门的流域环境法庭。但从流域环境法庭和流域环境巡回法庭的实践情况来看,还不能满足流域整体性保护的需要,也不能适应流域法的发展需求。我国流域司法机制建设,宜从流域环境法庭逐渐转到流域环境法院。流域环境法院的建立在我国环境司法专门化进程中具有必要性和可行性。按照流域法的保护理念和环境司法专门化的要求,流域环境法院的建设首先要合理设置审判机构,其次要科学设计程序制度,为流域生态环境保护提供强有力的司法保障。     

Collaborative Watershed Groups in Three Pacific Northwest States: A Regional Evaluation of Group Metrics and Perceived Success1

Chaffin, B.C., R.L. Mahler, J.D. Wulfhorst, and B. Shafii, 2011. Collaborative Watershed Groups in Three Pacific Northwest States: A Regional Evaluation of Group Metrics and Perceived Success. Journal of the American Water Resources Association (JAWRA) 48(1): 113‐122. DOI: 10.1111/j.1752‐1688.2011.00599.x Abstract: Watershed management through collaborative groups has become important throughout the United States over the past two decades. Although several studies of Oregon and Washington watershed groups exist, a definitive regional analysis of Pacific Northwest (PNW) watershed groups’ success is lacking. This paper uses data collected from a single survey instrument to determine the status, structure, and success of watershed groups in Idaho, Oregon, and Washington, respectively. Results indicate that watershed group member satisfaction with elements of group structure correlates with levels of perceived group success. Strong leadership within a group and a clear mission statement also indicate higher levels of perceived success. Contrasting realized successes among PNW watershed groups with metrics of perceived success constructed from survey data define watershed groups’ missions and goals and is validated by analysis of the Washington State planning groups’ responses. Overall, PNW watershed groups identified themselves as largely successful. Therefore, the structure, function, and operation identified as characteristic of PNW watershed groups could be used as a model for developing watershed group programming in regions with similar conditions.     

DETECTION OF FRESH WATER AQUIFERS IN THE GLACIAL DEPOSITS OF NORTHWESTERN MISSOURI BY GEOELECTRICAL METHODS1

Geoelectrical investigations in Grundy County of northwestern Missouri, where the groundwater resources of the glacial deposits have already been examined through an extensive drilling program by the Missouri Geological Survey and Water Resources, indicate that water-bearing gravel deposits can be distinguished from glacial deposits containing appreciable amounts of clay and limited amounts of water. The Schlumberger method used for the geoelectric depth soundings in the vicinity of the Survey's drillholes demonstrates the exploratory usefulness of the method in that it can partly replace the more expensive procedure of drilling. The method also provides improved interpretation between drillholes. Results of the investigation show that, in the area, clay has a resistivity below 20in, that the fresh water-bearing gravel at the bottom of the buried glacial stream channels has a resisitivity of 40 to 50fim, and that the near surface glacial gravel deposits have a resistivity above lOOfim. Interpretation of the depth soundings and the conductivity of water obtained from a local well implies that its water is drawn from the saline water of the bedrock. A recommendation is made for the quality improvement of this particular well.     

A COMPARISON OF METHODS OF ESTIMATING MEAN WATERSHED SLOPE1

ABSTRACT: Ten topographic analysis methods were employed to estimate watershed mean slopes for 13 small forested watersheds (32 to 131 mi²) in East Texas. Of the ten methods employed, the mean slope curve is the most accurate but also the most tedious and laborious one. The method can be simplified by measuring only the lengths of five contours and the areas between these contours within the watershed with little loss of its accuracy. Watershed slopes estimated by the contour length method, the grid contour method, the systematic slope sampling method, and the simplified contour length method are satisfactory for general purposes and relatively simple. The watershed circumference-stream length method, the length-width axis method, the Justin method, and the regression plane method are not suitable for estimating watershed slopes in East Texas without modification.     

Peak Runoff Model Comparison on Central Illinois Watersheds1

ABSTRACT: Four peak runoff rate models were tested with 183 gage years of record to determine the model most applicable to small watersheds of mild topography in east-central Illinois. The Cypress Creek, Rational, Chow, and SCS peak runoff models were evaluated for their performance. Statistical analyses indicated the Soil Conservation Service model was most appropriate for the watersheds tested.     

UNDERSTANDING A WATERSHED FROM THE BIOLOGICAL VIEWPOINT1

In watershed management the effects of plants on water cannot be considered a constant and forgotten because: plants of different sizes and forms use water at different rates and plants of the same size differ in their needs for water because of anatomical differences. Many common denominators are present in all watersheds covered by vegetation. Forces exerted on the soil water by vegetation, climate and soil are the same kinds of forces. The differences between watersheds in water yield potential appear to be due to differences in the degree in which these forces are exerted. However, the influence of biotic factors are more individual. The similarities and differences existing between watersheds suggest some principles that can be used as guides to understanding individual watershed problems and as possible guides to determining when, how, and where to treat a given watershed. Eleven principles are given and their application to the definition and solution of biological or vegetational problems of watershed management are discussed.