H23A-01
Characterization and Ground Water Management of two Rural Water Supply Sources in Kentucky and Illinois.
Ground water flow and particle tracking simulations were performed to characterize ground water flow trends in two aquifers that serve as water supply sources for two rural communities in Kentucky and Illinois respectively. The objective was to evaluate ground water management issues related to well head protection and the potential of increasing withdrawal rates in high-yield wells to meet future demands in water supply. Also, the water quality implications of potential increases in yield were analyzed. The impact of future expansion of residential developments and sewage disposal systems on the migration of contaminants into the aquifer was considered. The aquifers mainly are composed of sand and gravel overlain by clay and silt sediments. Well log data and ground water measurements of the alluvial aquifer in western Kentucky indicated that it is semi-confined and can be as thick as 80 feet in most areas. The alluvial aquifer in south central Illinois essentially is unconfined with an average thickness of about 70 feet. The U.S. Geological Survey computer codes MODFLOW and MODPATH were used for all the model simulations. For the aquifer in Kentucky, the Ohio River formed the western boundary of the model area with the bluffs in the eastern part being modeled as a flux boundary. For the aquifer in Illinois, the Illinois River formed the eastern boundary with the bluffs in the western boundary serving as a flux boundary. An unconfined conceptual model and a two-layer unconfined/semi-confined model were considered. The observed field ground water levels matched the latter model better for the alluvial aquifer in Kentucky. However, a one layer model was best suited for the aquifer in Illinois. The sensitivity of hydraulic conductivity, river conductance and recharge to the flow simulations were performed. Capture zone and areas of recharge were demarcated for each aquifer. Withdrawal rates of existing wells were increased to mimic increased future water supply. The resulting increase in drawdown did not cause excessive decrease in ground water storage nor drawdown, even under persistent drought conditions. Drought conditions were simulated with no recharge and low rive pools. Also, there was a little but insignificant increase in the capture zone as a result of the increase in the withdrawal rates. Under excessive recharge conditions (flooding), the rise of ground water with each aquifer was about 20 feet below ground surface. Thus, areas with outcrops of sandy material rather than silt and clay may be more vulnerable to surface and near-surface contaminant sources. This is particularly important at locations where new subdivisions could introduce contamination via septic systems. These rural areas do not have sewer treatment facilities. Additional observation wells are needed to characterize the two aquifers better.
H23A-02
Calibration and Validation of Storm Runoff Modelling to Predict Water Quality Impacts in the Bow River, Calgary, Alberta, Canada
As part of the Bow River Impact Study, City of Calgary (City) has been conducting hydrologic and water quality modelling projects. In order to support the modelling studies, City is monitoring rainfall since 1990 and runoff since 2001 within the city limits. The QHM model, a continuous simulation hydrologic model, designed primarily to assess the impact of urban land uses, was used in this study to simulate snowmelt runoff (winter), rainfall runoff (summer), baseflow runoff, and pond outflow. As part of the study, the QHM model was calibrated and validated using monitored runoff data for 14 urban catchments for the period 2001 to 2002. The calibrated and validated QHM model was then extended to 32 sub-watersheds representing the entire City for over a 16-year period (1990-2006). The results of the model showed that the simulated daily runoff agrees quite well with the recorded data for both the calibration and validation watersheds (7 watersheds each). As typical in any other computer simulation models, there were some discrepancies between the simulated and observed runoff, which is primarily due to recorded time steps of snowfall and rainfall, and assessment of Mean Areal Precipitation (MAP) method. Results of this study are being integrated into the Bow River Water Quality Model to predict water quality parameters downstream of the City by incorporating City's Wastewater Treatment Plant effluent data, water quality data of the tributaries to Bow River, meteorological data, and stormwater loading rates. This presentation will focus on the stormwater modelling methodology, results, and discussion related to uncertainty associated with modelling parameters and input data. Then the discussion will follow on a brief overview on how these data will be incorporated into Bow River Water Quality Model as a final product for City's decision making and future stormwater management guidance policies.
H23A-03
Occurrence of Pharmaceutical and Other Organic Compounds in Ground Water in Ten Regions of California, USA
A State-wide assessment of the occurrence of pharmaceuticals, pesticides, and other anthropogenic and natural constituents in ground-water aquifers that are used for public supply is being made as part of the California Ground-Water Assessment and Monitoring Program (http:ca.water.usgs.gov/gama/). During the first three years of the program, a total of 682 wells were sampled in ten areas of California representing a wide range of climatic, land-use, population density, and hydrogeologic conditions. Although the wells were generally deep (greater than 100 meters below land surface), the percent of wells containing at least one pesticide ranged from 15 to 88 in the ten study areas. In contrast, the detection frequency of pharmaceuticals ranged from 5 to 22 percent. Concentrations of pharmaceutical compounds were generally less than 50 parts per trillion. Of the 14 pharmaceutical compounds investigated, only 3 were detected in more than half of the study areas (carbamazapine, acetaminophen, and sulfmethoxazole) and only one was detected in more than 2 percent of the wells (carbamapazine). These 3 compounds have low soil-water partition coefficients (Kd) and are presumably less degradable, with respect to the time of transport to the sampled portion of the aquifer, compared to the other compounds. These 3 compounds are also a subset of the pharmaceuticals that have been detected most frequently in surface water. Several other pharmaceutical compounds that are frequently detected in surface water but not abundant in this study have high Kd values, suggesting sorption onto aquifer solids may limit their sub- surface transport, or have faster degradation rates. The occurrence of pharmaceutical compounds is not well correlated with that of pesticides, but may be related to land-use as the highest detection frequency occurred in the study unit with the highest urban density.
H23A-04
Eutrophication Study at the Panjiakou-Daheiting Reservoir System, Northern Hebei Province, People's Republic of China: Chlorophyll-a Model and Sources of Phosphorus and Nitrogen
Concentrations, loads, and sources of nitrate and total phosphorus were investigated at the Panjiakou and Daheiting Reservoir system in northern Hebei Province, Peoplefs Republic of China. The Luan He River is the primary source of water to these reservoirs, and the upstream watershed has a mix of land uses including agriculture, forest, with one large urban center. The reservoirs have a primary use for storage of drinking water and partially supply Tianjin City with its annual needs. Secondary uses include flood control and aqua culture (fish cages). The response of the reservoir system from phosphorus input, with respect to chlorophyll-a production from algae, was fitted to a model of normalized phosphorus loading that regresses the average summer-time chlorophyll-a concentration to the average annual phosphorus concentration of the reservoir. Comparison of the normalized phosphorus loading and chlorophyll-a response of this system to other reservoirs throughout the world indicate a level of eutrophication that will require up to an approximate 10-fold decrease in annual phosphorus load to bring the system to a more acceptable level of algal productivity. Isotopes of nitrogen and oxygen in dissolved nitrate were measured from the headwater streams and at various locations along the major rivers that provide the majority of water to these reservoirs. Those isotopic measurements indicate that the sources of nitrate change from natural background in the rivers to animal manure and septic waste upstream of the reservoir. Although the isotopic measurements suggest that animal and septic wastes are a primary source of nutrients, measurements of the molar ratio of nitrogen to phosphorus are more indicative of row-cropping practices. Options for reduction of nutrient loads include changing the management practices of the aqua culture, installation of new sewage treatment systems, especially in the one major urbanized area of the upper watershed, and agricultural management practices that would reduce the loading of nutrients and soil erosion from that land use.
H23A-05
Calculation and analysis of the non-point source pollution in the upstream watershed of the Panjiakou Reservoir, People's Republic of China
Panjiakou Reservoir is an important drinking water resource in Haihe River Basin, Hebei Province, People's Republic of China. The upstream watershed area is about 35,000 square kilometers. Recently, the water pollution in the reservoir is becoming more serious owing to the non-point pollution as well as point source pollution on the upstream watershed. To effectively manage the reservoir and watershed and develop a plan to reduce pollutant loads, the loading of non-point and point pollution and their distribution on the upstream watershed must be understood fully. The SWAT model is used to simulate the production and transportation of the non-point source pollutants in the upstream watershed of the Panjiakou Reservoir. The loadings of non-point source pollutants are calculated for different hydrologic years and the spatial and temporal characteristics of non-point source pollution are studied. The stream network and topographic characteristics of the stream network and sub-basins are all derived from the DEM by ArcGIS software. The soil and land use data are reclassified and the soil physical properties database file is created for the model. The SWAT model was calibrated with observed data of several hydrologic monitoring stations in the study area. The results of the calibration show that the model performs fairly well. Then the calibrated model was used to calculate the loadings of non-point source pollutants for a wet year, a normal year and a dry year respectively. The time and space distribution of flow, sediment and non-point source pollution were analyzed depending on the simulated results. The comparison of different hydrologic years on calculation results is dramatic. The loading of non-point source pollution in the wet year is relatively larger but smaller in the dry year since the non-point source pollutants are mainly transported through the runoff. The pollution loading within a year is mainly produced in the flood season. Because SWAT is a distributed model, it is possible to view model output as it varies across the basin, so the critical areas and reaches can be found in the study area. According to the simulation results, it is found that different land uses can yield different results and fertilization in rainy season has an important impact on the non- point source pollution. The limitations of the SWAT model are also discussed and the measures of the control and prevention of non- point source pollution for Panjiakou Reservoir are presented according to the analysis of model calculation results.
H23A-06
A model study of the coupled water quality and hydrodynamics in YuQiao Reservoir of Haihe River Basin, People's Republic of China
In recent years, eutrophication has become one of the most serious of global water pollution problems, especially in reservoirs, which is menacing the security of domestic water supplies. As the unique drinking water source of Tianjin within the Haihe River basin of Hebei Province, China, YuQiao Reservoir has been polluted and its eutrophic state is serious. To make clear the physical and chemical relationship between transport and transformation of the polluted water, a model package was developed to compute the hydrodynamic field and mass transport processes including total nitrogen (TN) and total phosphorus (TP) for YuQiao Reservoir. The hydrodynamic model was driven by observed winds and daily measured flow data to simulate the seasonal water cycle of the reservoir. The mass transport and transformation processes of TN and TP was based on the unsteady diffusion equations, driven by observed meteorological forcings and external loadings, with the fluxes through the bottom of the reservoir, plant (algal) photosynthesis, and respiration as internal sources and sinks. The solution of these equations uses the finite volume method and alternating direction implicit (ADI) scheme. The model was calibrated and verified by using the data observed from YuQiao Reservoir in two different years. The results showed that in YuQiao Reservoir, the wind-driven current is an important style of lake current, while the water quality is decreasing from east to west because of the external polluted loadings. There was good agreement between the simulated and measured values. Advection is the main process driving the water quality impacts from the inflow river, and diffusion and biochemical processes dominate in center of the reservoir. So it is necessary to build a pre-pond to reduce the external loadings into the reservoir.
H23A-07
Suggestions on water sources protection for the Gan River of Jiangxi, People's Republic of China
The Gan River is the largest river in Jiangxi Province, which is located in the southeast of China and is the second branch of the Yangtze River. The Gan River flows through Jiangxi Province from the South to the North and plays an important role in the economic development for 14 counties or cities with a population of 22 million. Currently, there are 5 drinking water sources, such as the capital city, Nanchang, with a daily capacity of 0.72 million cubic meters. With the rapid economic development and increasing population in the Gan River basin, water pollution has become more serious. The water quality of the river has serious pollution on both side reaches and slight pollution on the middle reach. In the upstream, the main pollution problems come from the industrial wastewater and soil erosion, with industrial and sewage wastewater affecitng the downstream region. Based on the Provincial Environmental Quality Report of 2005, of 39 monitoring sections, the ones which reach a favorable rating of a National Standard are 71.8 per cent. The water quality in the upstream region had a good situation with 80 percent of locations meeting standards, but the water quality downstream of the capital city deteriorates and only 45.4 percent of this region can meet the standard. Standards are frequently exceeded for BOD5, TP, TN, fecal coliform, and petrolueum oil in the downstream portion. The industrial wastewater drained into the river was 139 million tons in 2005, of which Nanchang city is the largest contributor with 214 million tons of wastewater composed of 75 million tons of industrial wastewater and 139 million tons of domestic sewage. The largest COD contributor was from Ganzhou in the upstream of the river with a total of 83,800 tons in 2005. Currently, there are only two wastewater treatment facilities with daily treatment capacity of 402,000 tons along the river, which are located in the capital city. Some parameters in the treated water stil exceed the drainage standard. Based on the characteristic of soil erosion in the mountain areas in the upstream portion of the Gan River, Jiangxi Province has carried out a strategy of comprehensive treatment of small river basins since 1983. A total of 374 small basins in Ganzhou city have been treated and 0.5 million hectare of soil erosion area have been treated which is 78.2 percent of the whole soil erosion in this region. Some suggestions on protection of water sources have been proposed as: to continue the comprehensive treatment of soil erosion, to enhance the treatment capacity of domestic sewage, to optimize the treatment technology and control sewage in the cities along the river, to formulate a plan for the basin water resources utilization, and to enhance the performance capacity of environmental protection laws and regulations.
H23A-08
Ecosystem Health Assessment of Urban Water Systems in Haihe River Basin, People's Republic of China
The Haihe River Basin contains large urban centers and a significant portion of the population of China. The assessment of ecosystem health of urban water systems is the scientific basis for the basin water resources management and ecological restoration. An indicator system was developed for the ecosystem and landscape, which contains three levels. It uses the weighted average fuzzy synthetic evaluation method to assess the health status of urban water systems in order to diagnose the restriction factors of ecosystem health. As a case study in Beijing, the results indicated that the Nanchang River was in a healthy state, the degree of membership belonging to the healthy state was 0.417. In contrast, the Yongding River, the Beihucheng River and the Liangma River were in an unhealthy state; their degrees of membership were 0.585, 0.854 and 0.901 respectively. Much attention should be paid to the urban water systems in the Haihe River Basin, especially for the evaluated systems with an unhealthy state index of over 0.8. These urban water system are very important for the overall integrity of the basin ecosystem.