This thesis reports the results obtained, and conclusions made regarding research into the hydrochemistry of a small impounded karst area in southeastern Australia. Water samples were collected from a variety of sites over a period of approximately six years and include samples that are representative of baseflow (drought conditions) and flood (high flow conditions) the two extremes of the flow regime. Four distinct water types were found to be associated with the karst spring and cave water sites sampled. In terms of physical, chemical and computed parameter values these have been classed as TYPE 1 water (median parameter values similar to those noted for the surface stream sites sampled with catchments of non-carbonate material); TYPE 2 water (catchment predominantly of limestone); TYPE 3 water (catchment predominantly of dolomite); TYPE 4 water (high median chemical concentrations). Spatial variation within the study area is considerable and intrinsic factors such as catchment lithology, the residence time of recharge, aspect and vegetation cover are the major natural controls in determining physical and chemical characteristics.

Philosophiae Doctor - PhD / Groundwater is an important of water resources and plays a significant role in the water supply in most parts of the world. It is also an important ecological environment factor, and its variations often affect natural balance of the ecosystem. China is one of the few countries in the world where Karst is intensively developed Karst water is heavily utilized as water supply source. Shanxi is such a province with largest Karst distribution in places in North China, where 19 large Karst springs and their catchment are identified to provide an important source of the water supply and ecosystem functioning in Shanxi

Karst springs are an essential source of private water supply in northeast Tennessee for various end-users. There are no regulatory standards for private (drinking) water quality in the state, unlike the public water system, while water users are only advised to test for contaminants in private water sources like springs or private wells. Water quality generally is spatially and temporally dynamic in terms of chemical quality, and more prominently in a karst environment, therefore, this study investigates the water quality of roadside springs used for drinking water. Parameters to be measured include E. coli, radon, and various physicochemical properties (pH, conductivity, dissolved oxygen, chloride, fluoride, sulfide, nitrite, and nitrate). I plan to collect 51 water samples from 51 spring locations so that spatial patterns in spring water quality can be evaluated using spatial interpolation, statistical correlation, or spatial regression. Spring water quality results will be compared to water quality of the streams into which these springs discharge. Preliminary work to be presented here includes identification of sampling sites and sampling strategies and integration of existing data, including geology and spring water quality data from a prior related study. Key findings will guide the delineation of the studied karst springs into risk regions for microbial, chemical, and radioactive content, and identification of key factors associated with high risk regions.

Between July 2009 and October 2011, a new habitat was found for a rarely reported freshwater dinoflagellate species, Thompsodinium intermedium - Comal Springs (Comal County), Texas. In 2011, diel in-situ monitoring in monospecific blooms of this species revealed previously undetected negative impacts on endangered species habitat availability associated with conditions of low flow levels, recorded at the U.S. Geological Survey gage # 08169000 on Texas Commission on Environmental Quality river segment 1811 station 12655. During a period of low springflow in the summer of 2011, late afternoon and early morning measurements of dissolved oxygen and temperature and presence of dinoflagellate blooms were monitored at six sites. Significant differences in diel fluctuations were found in all of these parameters among sites with and without the planktonic blooms. These fluctuations increased risk of hypoxia and hyperthermia conditions at sites of planktonic bloom events. Arrays of in-situ continuous monitoring temperature/light probes were used inside and outside of blooms. Wildlife and human health implications are that hypoxia and hyperthermia are known to promote conditions favorable to harmful microbes which may be transported from springs to coastal bays. In-situ data demonstrated that T. intermedium blooms, hypoxia, and hyperthermia occurred in the upper Comal headwaters. These natural environmental stressors may be avoidable if adequate springflows are maintained to buffer against these impacts.