Precipitation or evapotranspiration? Bayesian analysis of potential error sources in the simulation of sub-basin discharges in the Czech Elbe River basin

A global change assessment required detailed simulation of water availability in the Elbe River basin in Central Europe (148,268?km2). Using the spatially semi-distributed, eco-hydrological model SWIM, spatial calibration was applied. For 225 sub-areas covering the model domain (134,890?km2), evapotranspiration and groundwater dynamics were individually adjusted. The calibration aimed at good correspondences with long-term run-off contributions and the hydrographs for two extreme years. Measured run-off was revised from water management effects to produce quasi-natural discharges for calibration. At some gauges, there were large volume differences between these reference data and the simulations of the spatially uncalibrated model. Most affected were some sub-basins in the Czech part of the basin where the density of available climate stations was much lower than the German part. Thus, both erroneous precipitation data and systematic flaws in the evapotranspiration module of SWIM could have caused the differences. In order to identify the major error source and to validate the choice of spatial calibration parameters (evapotranspiration and groundwater dynamic corrections), MCMC analyses were made for three Czech areas. Optional precipitation correction had been considered by a third calibration parameter in the MCMC assessment. In two of the three cases, it can be shown that evapotranspiration corrections are preferable as precipitation errors are negligible. In the third case, where the analyses indicate a substantial error in precipitation data, an interpolation problem of the climate data at the edge of the model domain could be found. Hence, the applied method shows its potential to identify specific sources of uncertainty in hydrological modelling.     

Evaluation of surface water quality impacts of hazardous chemical sites

Common deficiencies in the typical evaluation of the surface water quality impacts of hazardous chemical sites are discussed. Particular attention is given to deficiencies in monitoring stormwater runoff, as well as the input of contaminated groundwaters that lead to impairment of the beneficial uses of nearby surface waters because of site-derived hazardous and deleterious chemicals. An alternative approach, Evaluation Monitoring, is presented in this paper. Evaluation Monitoring shifts the monitoring program from periodic sampling and analysis of stormwater runoff and ambient waters for a suite of chemical parameters, to examining the receiving waters to determine what, if any, water quality use impairments are occurring in surface waters due to the runoff-associated constituents and shallow groundwater input.     

Mammalian community characteristics on surface mine lands in Pennsylvania

Mammalian communities were studied on 10 surface mines over a four year period. The size and composition of these communities varied among the different areas. The size, composition, and spatial distribution of these mammalian communities were related to the structure of the plant community, and native plant species were of greater importance in determining size and composition of these communities than were those used in reclamation.     

ENVIRONMENTAL IMPACT OF STREAM CHANNELIZATION1

ABSTRACT Geologic, engineering, and biological investigations of six Pennsylvania coldwater streams were undertaken to determine the impact of channel modifications instituted both prior to and following Hurricane Agnes. The primary focus of the study was on the ecological changes brought about by stream channelization. No long-term deleterious effects on water quality, attached algae, benthic fauna, or forage fish populations were found. Trout, however, were found to be greater in numbers and weight in natural than in channelized stream reaches. Lack of suitable physical habitat appears to be the primary cause of reduced trout populations in stream reaches which have been channelized.     

EFFECTS OF DECREASING WATER DEPTHS ON THE SEDIMENTATION RATE OF ILLINOIS RIVER BOTTOMLAND LAKES1

ABSTRACT: The annual sedimentation rate of lakes and reservoirs is usually not evaluated for changes in depth relative to time. By using a linear regression with depth as the independent variable and annual rate of fill as the dependent variable the effect of changing depths is negated. According to both profile and linear regression analyses, Peoria Lake is filling faster in the more recent of two time spans but Lake Meredosia's increasing sedimentation rate is shown only by a linear regression. The probable cause for increasing sediment loads in the Illinois River is an almost twofold increase in row crop production in Illinois.     

REGIONAL WATER SUPPLY PLANNING STUDY FOR NORTHEASTERN ILLINOIS1

ABSTRACT: The development of a regional water supply system for the six-county area of Northeastern Illinois is presented in this paper, including: 1) the establishment of regional water supply technical planning policies; 2) the development and utilization of a regional water supply computer model to identify the principal and secondary sources of water supply for each entity in the study area, based on an apparent cost-effective source analysis; and 3) utilization of the study results to develop for the year 2010 a suggested preliminary regional water supply system. Using the findings from task 2 above, a proposed plan for overall Lake Michigan water use through the year 2010 was also developed. The effects of the proposed regional water supply system on future water levels in the deep aquifer were also discussed.     

THE ECONOMIC FEASIBILITY OF DUAL PURPOSE NUCLEAR DESALINATION OF GROUND WATER1

ABSTRACT: The economic feasibility of a large scale dual purpose (desalting water and power production) facility were evaluated. Although a site in the Tularosa basin of southern New Mexico was chosen as a case study for this analysis, it is believed that the approach and consequential results would be applicable to alternative sites in the Southwest. The basic project evaluated included: a) a ground water well field; b) a dual purpose, nuclear, desalination plant; c) a mineral recovery plant; and d) a reservoir for recreation and irrigation storage. Principle project outputs included electrical power, minerals, recreation, and water for either irrigated agricultural production or export to an adjoining river basin. Two alternative project designs were developed for detailed analysis. The first alternative encompassed all major project components. The results, in discounted net values used to assess the feasibility of the project, were essentially negative; that is, values were less than zero for full scale development. The net benefits ranged from $-986.57 million at a 5 percent discount rate, to $-1,137.528 million at a discount rate of 10 percent. In the second alternative, exportation of the desalted water from the Tularosa basin to two adjacent rivers was analyzed with somewhat better net benefits, ranging from $-382,527 million to $-478,612 million at the 5 and 10 percent discount rates.     

EFFECTS OF NITRATE AND PHOSPHATE CONCENTRATION ON NATURAL AQUATIC BACTERIAL POPULATIONS1

ABSTRACT: Natural aquatic bacterial populations in three streams located at the Savannah River Project, Aiken, S.C. have been studied in relation to the effects of ambient temperatures, dissolved River Project, Aiken, oxygen (DO), nitrate and phosphate concentrations. ³ 3 This work was supported in part by Contract #AT (38–1–824) with the U.S. Atomic Energy Commission, and was done in part in connection with AEC Contract #AT (07–2)–1.
Samples collected at monthly intervals for a period of one year from each system, were plated in duplicate at each of two dilutions on 1/4 strength Standard Plate Count Agar (Difco). After incubation at 25±1 °C for four days, total colony forming units, percent chromagens, and number of colony types (diversity) were determined and colonies were picked for identification. Temperatures were generally equal in two of the streams throughout the year, being lowest in Upper Three Runs (U3R) and Tirns Branch (TB), and highest in the Ash Basin System (ABS). DO content did not vary appreciably between the streams. Nitrates and phosphates were lowest in U3R, next lowest in TB, higher in the last station in ABS, and highest in the ash basin per se. Total colony forming units were highest in the ash basin, whereas chromagen percentage and diversity were highest in the last station in ABS. Results of these studies indicate that high nitrates and phosphates, in the absence of high organic carbon concentrations, have little, if any detrimental effect on the stability of natural aquatic bacterial populations.     

OPTIMIZING FLOOD CONTROL ALLOCATION FOR A MULTIPURPOSE RESERVOIR1

ABSTRACT. In the last decade much research has been devoted to applying the systems analysis approach to water resources problems. A popular research goal has been determination of the “best” method of operating a multipurpose reservoir. The goal of this study was to derive the economically optimum flood control diagram for a multipurpose reservoir by systems analysis. The technique employed to optimize the flood control diagram was programmed so that the optimization process could be applied to other multipurpose reservoirs. Two computer programs developed at the U.S. Army Corps of Engineers' Hydrologic Engineering Center were utilized with modifications to simulate the operation of Folsom Reservoir in central California. Economic analyses were incorporated along with an optimization technique into the reservoir operations program; and the resultant program was capable of routing a sequence of monthly reservoir inflows, computing benefits for various flood control diagrams (as dictated by the optimization procedure), and selecting the economically optimum flood control diagram. The univariate gradient technique was the optimization procedure employed. The two computer programs are on file at the Hydrologic Engineering Center in Davis, California.     

Effect of advanced oxidants generated via ultraviolet light on a sequentially loaded and regenerated granular activated carbon biofilter

The objective of this research was to investigate a sequentially loaded and regenerated granular activated carbon (GAC) biofilter system and to determine whether regenerative ozonation/advanced oxidation could improve the removal and biodegradation of a volatile organic compound from a contaminated airstream. Bench-scale reactors were constructed to operate in a manner analogous to a commercially available system manufactured by Terr-Aqua Environmental Systems (only with longer contact time). The GAC system consisted of two GAC biofilter beds that operated in a cyclical manner. On a given day, the first GAC bed adsorbed methyl isobutyl ketone from a simulated waste airstream, while the second bed underwent regeneration; then on the next day, the second bed was in the adsorption mode while the first was regenerated. Three bench-scale systems were used to compare the performance under three operating conditions: (1) ozone/ associated oxidant regeneration of a GAC biofilter system that was seeded with microorganisms from a field site, (2) a humid air regeneration of a seeded GAC biofilter, and (3) a humid air regeneration of an unseeded GAC biofilter. For the advanced oxidant regenerated GAC biofilter, a maximum removal efficiency of >95% was achieved with an empty bed contact time of 148 sec and an influent concentration of 125 ppm methyl isobutyl ketone, and 90-95% was achieved at 148-sec empty bed contact time and a 1150-ppm influent.