Time-consuming and expensive benthic surveys are currently the most common means of determining impacts on invertebrates and fish habitat in lotic systems. We propose using the rate of chitobiase production by benthic invertebrates as a complement for determining impacts on freshwater systems. We successfully modified the existing assay to a microplate approach for high throughput analysis of chitobiase activity. Next we conducted two case studies in: 1) the Dead Horse Creek, Manitoba, to determine if changes in chitobiase could detect impacts on the benthic community from wastewater effluent and; 2) in Snake and Kinch Creeks, Manitoba to see if chitobiase could be used to assess fish habitat quality. In both cases, we observed no strong relationships between chitobiase and traditional metrics (e.g., abundance, biomass, diversity). We recommend further studies concerning the timing of chitobiase release in lotic systems and assessments of its use in mesocosm and microcosm toxicity studies / May 2016

The Lea Navigation in the north-east of London, a canalised reach of the River Lea, is affected by episodes of very low levels of dissolved oxygen. The problem was detected by the Environment Agency in the stretch from the confluence with Pymmes Brook (which receives the final effluent of Deephams sewage treatment works) to the Olympic area (Marshgate Lane, Stratford). In this project, possible causes and sources of the poor water quality in the Lea Navigation have been investigated using a multi-parameter approach. A study of physico-chemical parameters, obtained from Environment Agency automated monitoring stations, gave a clear picture of the poor river water quality at three sites in this reach. River water ecotoxicity to the freshwater alga Pseudokirchneriella subcapitata was determined by algal growth inhibition tests, following the OECD guidelines. Moreover, a novel protocol was developed which involved the use of E. coli biosensors (CellSense) operating at a lower potential than the standard protocol and using pre-concentrated river water samples. This protocol is promising and it has the potential to be a useful tool to determine the toxicity of contaminants at environmental concentrations. Furthermore, the developed protocol is a rapid, easy to perform bioassay, with potential application in achieving the aims of the Water Framework Directive (WFD). In addition to the data from the Environment Agency automatic monitoring stations and the laboratory-based tests, two in situ monitoring approaches were performed: 1) a detailed spatial seasonal monitoring of physico-chemical parameters of river water at twenty-three sites, and 2) algal growth inhibition tests, with algae entrapped in alginate beads, at seven monitoring stations. Results showed chronic pollution, and identified polar compounds in the river water and high bacterial concentrations as possible causes of low dissolved oxygen levels. This study confirmed the negative impact of Deephams STW (throughout Pymmes Brook) on the water quality of the Lea Navigation. However, there was evidence of other sources of pollution, in particular Stonebridge Brook was identified as uncontrolled source of pollution and untreated wastewater. Other possible sources include Old Moselle Brook, diffuse pollution from surface runoff, boat discharges and other undetected misconnections. Finally, in the light of the WFD, this project provides a case study on the investigation of river water quality, providing evidence that the multiparameter approach is reliable, and low cost approach for the monitoring of freshwater bodies.

Västervik Municipality has had problems with odorous compounds in its primary water source, Lake Hjorten. Geosmin and cyanobacterial blooms have been detected in the lake. This report aims to experimentally investigate the cyanobacterial populations in the primary and secondary freshwater lakes depending on the climate change factor temperature. An understanding of number of cells is the foundation to understand the potential harmful chemical levels. This provides an opportunity to predict the water quality in the lakes in the future due to climate change. The results show that cyanobacteria did not benefit from an increase in temperature from 10°C to 18°C solely during autumn. However, the diatom Aulacoseira did increase in numbers although it is not known to produce odorous compounds. Consequently a warmer Swedish autumn would not cause worse drinking water quality in absence of other contributing factors according to this study.

Eight natural waters from throughout the United States were subjected to different degrees of alum coagulation and activated carbon adsorption treatment (not in series). The concentration of trihalomethanes (THMs) formed by the reaction between the natural aquatic organics and doses of free chlorine were determined by gas chromatography at ten discrete time intervals over a total of 168 hours of reaction time. Since bromide ion concentration and temperature were held constant, and the chlorine dose was based on the final nonvolatile total organic carbon (NVTOC) concentration, THM formation was modeled with the independent variables: reaction time, pH, and a surrogate parameter for organic precursor. Several surrogate parameters were investigated to quantify the THM formation potential. A multiplicative surrogate (UV*TOC) representing the product of the NVTOC concentration and the UV adsorbance at 254 nm was found to be the best surrogate for activated carbon treated waters and was found to be approximately equivalent to NVTOC for alum treated waters. The THM formation was found to fit a two stage reaction with respect to reaction time; relatively rapid formation in the first eight hours followed by a slower formation from 24 to 168 hours. The data base was analyzed with a statistical software package that performs multiple linear regression analysis. Three types of models were developed: a linear model, a nonlinear model and a logarithm transform model. The models were checked for predictive accuracy by a number of methods including the examination of statistics from the regression analyses, scatterplots of predicted versus observed THM values, and the number of predicted values within 20% of the observed value. The logarithm transform model was found to be the best overall model, although other models were more accurate for specific applications as to reaction time or water type. Gel permeation chromatography (GPC) was employed to examine the molecular weight distribution of the aquatic organics in three of the eight waters and to determine the effects of alum coagulation and activated carbon adsorption on these distributions. In general, alum coagulation preferentially removed high molecular weight organics while activated carbon removed a broad spectrum of molecular weight organics.

A key question related to climate change projections is how will aquatic systems respond to changes in variables such as temperature and precipitation? This thesis uses GWLF, a simple catchment scale model to explore potential impacts of climate change on water quantity and quality. River discharge and nutrient loads were modelled for several warmer world scenarios. For one catchment in New York, USA changes in annual dissolved phosphorus loads decreased along with annual streamflow, and particulate phosphorus loads increased for a single future climate scenario. For the Galten catchment of Lake Mälaren, Sweden, the spring melt peak observed historically was reduced for six future scenarios. Peak runoff and dissolved phosphorus and nitrogen load maxima occurred in winter rather than early spring. A synthesis of model results for dissolved inorganic nitrogen (DIN) loadings for five European catchments showed changes in the timing and magnitude of peak DIN load for several future scenarios. In northern Europe, changes were largely due to increased winter streamflow and reduced snow pack and spring melt runoff. In western Europe, DIN loads increased in winter or early spring due to increased precipitation. The biological response for a warmer future scenario was modelled for the Galten basin of Lake Mälaren using GWLF coupled to a lake phytoplankton model and a physical lake model. An increase in cyanobacteria biomass accompanied by a decline in diatom biomass resulted from changes in the timing of nutrient export from the catchment. The projected increase in lake temperature favored an overall increase in total phytoplankton biomass. Lastly, a method based on hourly measurements of colored dissolved organic matter (CDOM) fluorescence provides the appropriate data for dissolved organic carbon (DOC) model parameterization and may also be used for surveillance of organic matter inputs to lakes.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

<p>This study focuses on valuation of natural resources and particularly valuation of the quality of a natural resource. The aim is to value an improvement of water quality, measured as sight depth, in the bay Himmerfjärden in the Stockholm archipelago. It is desirable to attain a value of a one metre sight depth improvement in Himmerfjärden and to analyse how a sight depth improvement affects the demand for travelling to Himmerfjärden. A condtional logit model is applied to obtain these values from survey data. The benefits of a one metre sight depth improvement in Himmerfjärden, will yield 162 260-1 599 420 SEK per year, adjusted to the price level of 2007. The estimated value depends on how travel time is treated and whether a commute variable is included or not. Furthermore will a one per cent sight depth improvement in Himmerfjärden increase the demand for travelling to Himmerfjärden with approximately 0.13-0.18 trips on a given choice occasion. These results indicate that there are values attained to the quality of a natural resource.</p>

Riparian areas are valuable resources, particularly in semi-arid areas where water is usually scarce and rapid streamflow responses to runoff are common. Only recently has the importance of in-channel recharge during high streamflow periods ("floods") been recognized in rivers with gaining and losing reaches where recharge processes and flowpaths can be very complex. This dissertation builds upon this recent work by investigating how three factors influence how riparian systems respond to floods over a range of temporal and spatial scales. First, the impact of differences in local hydrogeologic forcings are investigated at the seasonal and 50 meter-reach scales. Second, the significance of flood event size and duration is studied at the multi-year and river (~50 Km) scale. Third, an underlying mechanism behind how changes in bed sediment composition can influence stream-aquifer interactions at the event- and point-scales is developed. Major findings of this work include observations along the Upper San Pedro River of seasonal floodwater storage below moderately gaining reaches and longer-term storage below losing reaches (seasonal to multi-year depending on the nature of the riparian groundwater flow system). The longest and largest floods (with respect to flow volume) dominate floodwater recharge in the Bill Williams River and an apparent flood size and duration threshold exists. This threshold must be met or exceeded in order for individual events to induce observable amounts of recharge that can then influence the amount and composition of later streamflow. This threshold agrees with the process presented here involving preferential mobilization and deposition of fine bed sediment particles--which dictate hydraulic conductivity--during each event that would lead to disproportionately more recharge during large floods. Forecasts of increased precipitation intensity and decreased annual precipitation in some regions, including the southwestern United States, due to changes in the earth's climate are likely to make floods a more important driver of riparian hydrologic processes. Consequently, the work presented here and other process-based studies of how floods influence riparian hydrology and water quality will be useful in making well-informed decisions regarding riparian preservation, management and restoration as human demands and the global climate change in the future.

80 pp. / Arizona: Know Your Water. A consumer's guide to water source, quality, regulations and home water treatment. / This well owners guide presents detailed sections to assist the reader in becoming familiar with water quality concepts, drinking water guidelines and water testing. The reader can also become familiar with Arizona specific aquifers, conditions and activities that determine ground water quality. Well owners can also review and become familiar with well construction, components and maintenance needed for the safe and proper function of their wells. Finally, a section on water treatment technologies and selection, based on water quality conditions is presented. Well owners will be able to refer to this section for the selection of water treatments, should they choose to improve the water quality of their wells. Includes numerous illustrations.

3 pp. / Arizona Well Owner's Guide to Water Supply / To develop a ground water resource, it is necessary to design and construct a well capable of yielding a pumping rate compatible with the needs of the water well owner. Sufficient and sustained well yields are highly dependent on the characteristics of the aquifer, the construction of the well, and the maintenance of the well. Causes of low-yielding wells are explained and practices to restore well performance are recommended.