To see the other types of publications on this topic, follow the link: Baseflow.
Dissertations / Theses on the topic 'Baseflow'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 47 dissertations / theses for your research on the topic 'Baseflow.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ng, Nicole. "Spatiotemporal variations of baseflow generation in the United States." Thesis, State University of New York Col. of Environmental Science & Forestry, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10192876.
Full textAbstract:
The traditional paradigm of baseflow generation assumes a uniform water table contributes baseflow evenly across a watershed. This thesis considers an alternate paradigm in which baseflow originates from a mix of localized sources that drain at different rates. Four forested headwater catchments across the United States were examined for spatial variability in baseflow sources by analyzing fractional baseflow contribution from each subcatchment relative to the catchment outlet. This revealed that subcatchment flow contributions changed dynamically through time, supporting the idea of different drainage rates in different places. A parallel linear reservoir model, which is predicated on heterogeneity in flow sources and not groundwater hydraulics, was used to simulate results consistent with observations in some of the study catchments. These results support the idea that in some locations baseflow recession may be better explained by landscape spatial heterogeneity than by aquifer hydraulics.
2
Baillie, Matthew Nelson. "Quantifying baseflow inputs to the San Pedro River a geochemical approach /." Thesis, The University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2005_019_sip1_w.pdf&type=application/pdf.
Full text
3
Thorsell, Anna. "Drainage of flooded water : effects on baseflow in Awanui Stream, New Zealand." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-169200.
Full textAbstract:
In the Heretaunga Plains area, New Zealand, parts of the low lying land adjacent to the Awanui Stream are flooded annually. The purpose of the study was to find out if the flooding water trapped in the field gets sealed off from infiltrating the soils in any way (and hence is unavailable to replenish the stream flow). What would be the effects on stream base flow if pumping of the flooding water would occur direct to the stream after wet periods and heavy rains? The method of this project was to investigate the infiltration, soil type and ground water conditions in the field. The infiltration was investigated with the help of a double ring infiltration test, a disc permeameter that measures hydraulic conductivity, and pvc-pipes with core samples were saturated for an extended period of time to find out if there was any kind of seal forming during saturated conditions. The soil in field was sampled and a soil fraction test was performed. The potential evaporation was measured with an evaporation pan and calculated with data from a climate station in field. With flow records from the outgoing drain, potential evaporation and precipitation data a rough water balance model could be created. The results showed that there is no seal formed in the top part of the soil profile preventing the water from infiltrating. The flooding water is the result of a rising groundwater table, on top of a thick clay layer seven meters down in the ground. Once the flooding water has drained and evaporated away there is nothing wrong with the infiltration rate in field. There are very fine particles of silt and clay in the top soil that decreases the infiltration rate and can cause a separation of the ground water and the water above land surface. When the project was finished two recommendations could be given to the landowner to solve the problem with the flooding. The recommendations were to either re-level the field to get the surface water to runoff towards the drains instead of being trapped in the current low parts of the field. Or to dig drains from Horonui Drain and Cambell Drain into the field's low parts and in that way drain the flooding water away.I området Heretaunga Plain, Nya Zeeland, översvämmas årligen delar av det låglänta området kring floden Awanui Stream. Syftet med den här studien var att ta reda på om översvämningsvattnet i fält hindras från infiltration i jorden på något sätt (och kan där med inte bidra till basflödet till floden). Vad skulle effekterna på basflödet i floden bli om översvämningsvattnet pumpades direkt ut i floden efter våtare perioder och större regn? Metoden för att svara på detta var att undersöka infiltrationen, jordtyperna och grundvattenförhållandena i fält. Infiltrationen undersöktes med hjälp av dubbelring infiltrationstest, en s.k. disc permeameter användes för att undersöka den hydrauliska konduktiviteten och PVC-rör med borrkärnor ställdes under vattenmättadeförhållanden en längre tid för att ta reda på om infiltrationen då skulle förändras. Jorden i fält provtogs och ett kornstorlekstest utfördes. Den potentiella avdunstningen mättes med en evaporationspanna och beräknades med data från en klimatstation i fält. Med flödesdata från diket med utgående vatten, potentiell avdunstning och nederbördsdata kunde en grov uppskattning av vattenbalansen i fält göras. Resultaten visade att det inte bildas någon hinna som hindrar infiltrationen av vatten i den övre delen av jordprofilen. Översvämningen är ett resultat av en stigande grundvattenyta, som stiger från ett tjockt lager av lera 7 meter ner i marken. När vattnet har dräneras och avdunstat bort är det ingenting som hindrar infiltrationen i fält. Det är dock väldigt fina partiklar av silt och lera i den översta torvjorden som minskar infiltrationshastigheten och kan orsaka en separation av grundvatten över och under markytan. När projektet var avslutat kunde två rekommendationer ges till landägaren om hur man kan lösa problemet med översvämningen. Rekommendationerna var att antingen skulle landägaren kunna göra om marknivån i fält för att få ytvattnet att rinna av mot dikena istället för att vara fast i de lägre partierna av fältet. Eller att gräva diken in i fältet från Horonui Drain och Cambell Drain in till de lägre översvämmade områdena i fält för att dränera bort översvämningsvattnet.
4
Neary, Daniel G., and John N. Rinne. "Baseflow Trends in the Upper Verde River Relative to Fish Habitat Requirements." Arizona-Nevada Academy of Science, 1997. http://hdl.handle.net/10150/296476.
Full text
5
Hidayat, Noor 1952. "Baseflow evaluation of a logged small watershed of the Bull Run River, Oregon." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/278028.
Full textAbstract:
The impact of logging operation on baseflow yield on the Bull Run Municipal watershed, Oregon was examined. Daily streamflow data, from 1958 to 1984, for the three small watersheds on the Bull Run river were analyzed. The baseflow recession coefficient was determined by analyses of successive days flows. Least squares and linear regression analysis were utilized to evaluate the effect of treatments. It was shown that logging of 25 percent of total treated watershed reduced mean daily baseflow yield, but this was not significantly different at either the 0.05 or 0.01 level. Also, it was shown by the untreated watershed that there was a significant difference, at the 0.05 level, of baseflow yield between the period of pre- and post-logging. The decreased baseflow yield may have resulted from decreasing fog drip and increasing evaporation rate in the logged areas and from decreasing precipitation on the watersheds during the post-logging period.
6
Roningen, Jeanne Marie. "Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/31950.
Full textAbstract:
Mountain Lake in Giles County, Virginia, has a documented history of severe natural lake-level changes involving groundwater seepage [Jansons, 2004] that extend over the past 4200 years [Cawley, 1999], and as of December 2010 the lake was about 2% full by volume. Situated in the Valley and Ridge physiographic province on the axis of a plunging anticline and straddling contacts between three upper Ordovician and lower Silurian formations, the lake is one of two natural lakes in Virginia.
A daily water balance, geophysical surveying with dipole-dipole electrical resistivity, and chemical sampling have shed light on the nature of flow to and from the lake, including: 1) the steady nature of net groundwater outflow, 2) the seasonal response to precipitation of a forested first-order drainage system in fractured rock, 3) the influence of a fault not previously discussed in literature regarding the lake, and 4) the possibility of flow pathways through karst features.
Results from a water balance indicate steady lake drainage and significant recharge when vegetation is dormant, particularly during rain-on-snow melt events. The resistivity profiles display a highly heterogeneous subsurface and reveal low-resistivity areas that suggest flow pathways to and from the lake. Well logs, satellite images, and outcrop observations appear to confirm the presence of a fault to the east of the lake. Chemical evidence suggests that karst features may be present in the upper Reedsville-Trenton formation underlying the lakebed.
Master of Science
7
Simpson, Scott. "Modeling Stream-Aquifer Interactions During Floods and Baseflow: Upper San Pedro River, Southeastern Arizona." Thesis, The University of Arizona, 2007. http://hdl.handle.net/10150/193338.
Full textAbstract:
Streams and groundwaters interact in distinctly different ways during flood versus base flow periods. Recent research in the Upper San Pedro River using isotopic and chemical data shows that (1) near-stream, or 'riparian,' groundwater recharged during high streamflow periods is a major contributor to streamflow for the rest of the year, and (2) the amount of riparian groundwater derived from this flood recharge can vary widely (10-90%) along the river. Riparian groundwater in gaining reaches is almost entirely basin groundwater, whereas losing reaches are dominated by prior streamflow.This description of streamflow gives rise to the questions of (1) how much flood recharge occurs at the river-scale, and (2) subsequently, what is the relative importance of flood recharge and basin groundwater in maintaining the hydrologic state of the riparian system. To address these questions, a coupled hydrologic-solute model was constructed for 45 km of the Upper San Pedro riparian system.
8
Schulte, Marc Alan. "Dilution Gauging as a Method to Quantify Groundwater Baseflow Fluctuations in Arizona's San Pedro River." Thesis, The University of Arizona, 1997. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0133_sip1_w.pdf&type=application/pdf.
Full text
9
Shukla, Sanjay. "Impacts of Best Management Practices on Nitrogen Discharge From a Virginia Coastal Plain Watershed." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29928.
Full textAbstract:
Long-term watershed and field nitrogen (N) balances were used in this study to quantify the surface (baseflow) and ground water lag times and effects of BMPs on N discharge from a Virginia Coastal Plain watershed. Ten-year water quantity/quality data (1986-1996) collected at the Nomini Creek (NC) watershed were used. Field (Field-N) and watershed (Watershed-N) scale N models were developed for computing the N balances. BMPs evaluated in this study included no-till corn and split N application. The role of atmospheric N (atm-N) deposition (dry+wet) in masking the effects of BMPs on watershed N loading was also investigated. Nitrogen retention and discharge from the forest areas in the NC watershed were simulated using the 5-year water and N input and output data from forested subwatersheds. Field and watershed N balances (WNBAL) were used to evaluate the effects of BMPs on measured surface and ground water N in the NC watershed.
A 6-month laboratory study was conducted to develop N mineralization (Nmin) models for agricultural, forest, and fallow soils in the NC watershed. Mineralization potential (N0) and rate constants (k) for surface and subsurface soils from agricultural, forest, and fallow soils were estimated by fitting the laboratory measured data to a first-order model, using the nonlinear regression procedure. A large variability (300%, 163 - 471 kg/ha) in N0 of agricultural surface soils was observed. On average, forest soils had much higher potentially mineralizable N than agricultural soils. The first-order model was incorporated into the Field-N model to predict daily Nmin using the measured N0 and k and daily values of soil water and temperature.
Atmospheric deposition was a major source of N in the NC watershed, accounting for 23% of the total N input. Variation in atm-N deposition during the 10-year period was from 10 to 42 kg/ha (average = 25 kg/ha); much larger than the variation in fertilizer N (37 to 51 kg/ha). Atm-N deposition was found to be a controlling factor affecting surface water DIN (dissolved inorganic N) and TDN (total dissolved N) loading in the NC watershed; an indication that atm-N deposition is a masking factor in the BMP impact evaluation. Large uncertainty in atm-N deposition existed due to uncertainty involved in quantifying dry N deposition. Forested areas of the NC watershed retained 77% of the atm-N deposition. Forest area N discharge was simulated using the 77% retention and annual atmospheric deposition.
Comparison of Field-N predicted N balance and leaching (steady-state and transient conditions) with observed ground water NO3 concentration revealed that the ground water lag time ranged from 2 to 8 months. Unusually rapid transport of solute in the watershed was facilitated by the network of discontinuous clay lenses. Based on the lag time, the pre-BMP (1986-1990) and post-BMP (1991-1995) periods were defined. Results from Field-N indicated that implementation of split fertilizer N on corn reduced the post-BMP ground water NO3 concentration by 10-12% at two of the four ground water monitoring sites. The split N application reduced the frequency of detection of high NO3 (> 9 mg/l) concentration by 44% during the post-BMP period. Considerably large uncertainty existed in evaluating the effects of BMPs on ground water NO3 due to N contributions from neighboring agricultural and forest areas. Effects of no-till corn could not be evaluated since this BMP was already implemented at the sites prior to the beginning of the study. Results of statistical trend analysis of the ground water N supported the modeling results.
Watershed-N model was able to accurately predict the effects of land use activities on watershed N balances (WNBAL) and baseflow and ground water N. A one-to-one relationship between the WNBAL and observed N loading and concentration time series was observed. Comparison of WNBAL and measured baseflow N revealed that the baseflow lag time or residence time was between 4-11 months. Multivariate regression models were developed to predict baseflow N using Watershed-N results. The multivariate model predicted the N loading and concentration exceptionally well (R2 > 90%). Corn N input and output and acreage was an important predictor of ground water N and baseflow N loading and concentration.
Post-BMP WNBAL was considerably less than the WNBAL for the pre-BMP period. However, these reductions were mainly due to the 43% reductions in atm-N deposition and 31% increase in the plant uptake during the post-BMP period. Reductions in WNBAL caused by BMPs were only 5%. Reductions in N loading caused by BMPs were 10%. Statistical trend analysis of monitoring and modeling results indicated significant post-BMP reductions in WNBAL and DIN and TDN loading. However, poor to moderate evidence was available to suggest that BMPs caused a significant reductions in WNBAL and N loading. Marginal effects of BMPs could mainly be attributed to insufficient BMP implementation. Watershed-N was used to evaluate N reduction scenarios and to design BMPs. Irrigating corn was one of the best BMPs, as it could reduce N loading from NC watershed by 50%. Quantification of lag time and long-term watershed N balances from this study provide crucial information for understanding N cycling and factors controlling N discharges which is essential for designing programs for controlling N discharges from Mid-Atlantic Coastal Plain watersheds.Ph. D.
10
Cameron, Stewart Graham. "A hydrogeological study of the interaction between Avon River baseflow and shallow groundwater, Christchurch, New Zealand." Thesis, University of Canterbury. Geology, 1992. http://hdl.handle.net/10092/8023.
Full textAbstract:
The relationship between shallow groundwater levels and Avon River baseflow upstream of Gloucester Street has been investigated. Avon River baseflow is supplied by shallow groundwater-fed springs. Historical and anecdotal information indicate that since European settlement of the Christchurch area in the 1850's, Avon River baseflow has declined. The baseflow decline is attributed to the progressive lowering of the Christchurch area watertable which has caused downstream migration of headwater spring positions and a reduction in spring discharge. Prior to this study minimal historical Avon River flow data existed, and a quantitative estimation of the decline in
baseflow is not possible. A management plan for maintaining acceptable baseflow levels in the Avon River is currently being developed by the Canterbury Regional Council. The aim of this study was to provide information on the relationship between Avon River baseflow and shallow groundwater levels to aid baseflow management.
The Christchurch groundwater system is characterised by a watertable aquifer that overlies a series of layered confined aquifers. Direct groundwater discharge into the Avon River is considered to be from both the watertable aquifer and upper most confined aquifer. Groundwater was found to enter the river system by two different mechanisms; seepage through stream bed gravel and artesian spring discharge.
Groundwater seepage through streambed gravel occurs where the stream channel intersects the watertable aquifer. Artesian springs occur where water-bearing gravels are overlain by between approximately 1 to 10 m of finer-grained confining sediment.
Artesian spring water is thought to flow from both the watertable aquifer and the uppermost confined aquifer. Pipes through the confining sediment connect the spring vent to the underlying water-bearing gravels. When the hydraulic head of the underlying gravel aquifer is above the stream stage artesian spring flow will occur.
Tributary baseflow and shallow groundwater data were collected for the 11 month period, February 1992 to January 1993. In addition, baseflow was separated from the
Avon River flow record. Available flow data indicate that mean A von River baseflow at Gloucester Street from 1980 to 1992 was approximately 1700 1/s. In March 1993
Avon River baseflow was 50% of that in March 1980. Large rainfall events in late-August 1992 caused Avon River baseflow in January 1993 to increase to approximately 77% of the March 1980 value.
Regression analysis established a relationship between both hydraulic head in the upper most confined aquifer and unconfined watertable levels, to Avon River baseflow (R² > 0.8). The flow hydrograph showed that the daily abstraction of shallow groundwater from beneath the catchment caused an associated reduction in flow. Seasonal fluctuations in spring discharge and baseflow were found to be greater in the western tributaries than the eastern tributaries. This is attributed to the greater seasonal fluctuation of shallow groundwater levels in the western area of the catchment than in the eastern area. From available data the peak in seasonal groundwater levels occurred throughout the study area during the period of 24-27 October 1992. No observable time delay occurred between the seasonal peaks in shallow groundwater levels and Avon River baseflow at Gloucester Street.
In order to sustain acceptable rates of Avon River baseflow, shallow groundwater levels need to be maintained in areas of the catchment were groundwater enters the river. As a first step, the Canterbury Regional Council has placed restrictions on the abstraction of groundwater in areas where springs occur. The information presented in this study on the relationship between shallow groundwater levels and Avon River baseflow confirms the need for management of shallow groundwater levels in areas where groundwater contributes to baseflow. To ascertain the effectiveness of remedial measures continued monitoring of A von River baseflow and shallow groundwater levels are necessary.
11
Wilson, Chantel. "Effect of Golf Course Turfgrass Management on Water Quality of Non-tidal Streams in the Chesapeake Bay Watershed." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51683.
Full textAbstract:
Turfgrass management activities on golf courses have been identified as a possible source of Chesapeake Bay nutrient pollution. Total Maximum Daily Load goals are in place to reduce nutrient amounts entering the Bay. Dissertation investigations include (1) the role of golf course turfgrass management in nutrient deposition or attenuation in local streams, (2) estimations of total nitrogen (N) discharging to the watershed from stream outlet points as a function of land use and watershed area, and (3) other factors potentially affecting water quality on golf courses, including soil characteristics and use of best management practices (BMPs). Total N, nitrate-N, ammonium-N, phosphate-phosphorus (P), streamwater temperature, specific conductance (SpC), pH and dissolved oxygen (DO) were sampled at 12-14 golf course stream sites in the James River and Roanoke River watersheds during baseflow conditions. Discharge was determined at outflow locations. Unit-area loads (UALs) were calculated from monitoring data. These UALs were then compared to UALs from Chesapeake Bay Watershed Model land use acreages and simulated loads for corresponding watershed segments. Virginia golf course superintendents were also surveyed to determine BMP use. No consistent impairment trends were detected for streamwater temperature, SpC, pH, or DO at any of the sites. Outflow NO3-N was below the 10 mg L-1 EPA drinking water standard. However, some sites may be at increased risk for benthic impairment with total N concentrations >2 mg L-1, as suggested by VADEQ. Significant increases in nitrate-N at OUT locations were measured at four sites, whereas decreases were measured at two sites. Ammonium-N significantly decreased at two sites. Golf course N UALs calculated from baseflow monitoring were lower than or similar to UALs estimated for forested areas in the associated watershed segment at seven out of the 12 sites. Golf course UALs ranged from 1.3-87 kg N ha-1 yr-1. Twenty-one of 32 surveyed BMPs had an adoption rate ≥50% among survey respondents. In most cases, presence of golf courses generally does not appear to significantly degrade baseflow water quality of streams in this study. Management level appears to be an influencing factor on water quality and concerns may be heightened in urban areas.Ph. D.
12
Neurath, Robert Carl. "Comparative Baseflow Hydrochemistry of Various Septic System Density Groups within the Yellow River Watershed, Gwinnett County, Georgia." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/geosciences_theses/9.
Full textAbstract:
Baseflow water chemistry between different septic system density groups was analyzed to understand how septic system usage impacts the water quality of the Yellow River Watershed located in Gwinnett County, Georgia. Seventy water samples were collected at baseflow conditions in the summer of 2006. The samples were analyzed for the abundance and distribution of chlorides, sulfates, nitrates, and specific conductance. Geographic Information Systems were used to determine sample collection sites, assign samples into density groups, and spatially analyze and display the results. Statistical methods were used to compare the results of each density group with all others,and to find any correlation of the anions with respect to specific conductance. Regression coefficient values between nitrate and specific conductance in all groups average 0.77 and the elevated nitrate concentrations in group four suggest a limited relationship between septic system density and baseflow water quality.
13
Crites, Hugo. "Distribution of Icings (Aufeis) in Northwestern Canada: Insights into Groundwater Conditions." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39733.
Full textAbstract:
Icings, also known as aufeis, are groundwater fed sheet-layered ice bodies that normally forms in local depression or more often in low angled, shallow river beds. Understanding their distribution in the Mackenzie Valley corridor (N.W.T.) and adjacent Yukon (618,430 km2) provided important insights to groundwater discharge and recharge. This study aimed at; i) creating the first extensive map of icings in Northwestern Canada, using over 500 late-winter scene Landsat 5 and 7; and ii) assessing hydrographic parameters (streamflow, baseflow and winter contribution) and terrain factors (slope, permafrost, geology) on icing distribution at the watershed level. Results show that; 1) icings are likely to develop close to geological faults on carbonate foothills and mountainous terrain, where continuous permafrost is present and on slopes of less than 5 degrees; 2) in the continuous permafrost zone, the cumulative surface area of icings, winter discharge and winter contribution to total annual discharge have significant positive relations with watershed extents. Icings located at the southern boundary of continuous permafrost are more sensitive to degrading permafrost and the predicted increase in groundwater discharge which may lead to a later icing accretion and earlier ablation during the year.
14
Donelan, Jack E. "Groundwater-Surface Water Interaction in the Kern River| Estimates of Baseflow from Dissolved Radon Analysis and Hydrograph Separation Techniques." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10841176.
Full textAbstract:
Geochemical mixing methods utilizing 222Rn and chloride and statistical hydrograph separation techniques were carried out in an attempt to understand baseflow dynamics in a section of the Kern River in the Sierra Nevada of Southern California. 222Rn has become a valuable tool for evaluating groundwater inflow to a river, particularly when groundwater and surface water have similar major ion geochemistry. When using geochemical methods it is important to minimize uncertainty through comparison with separate tracers and techniques, though this is complicated in this setting. Snow melt discharge and regulation of natural river flow cause hydrograph-based techniques to suffer from inaccuracies. Geochemical mixing using major ions and stable isotopes are complicated by the chemical similarity between surface water and groundwater. 222Rn is a powerful tool to elucidate this relationship in this setting if major uncertainties, like rate of radon degassing and parafluvial and hyporheic radon production can be constrained.
15
Beaulieu, Mathieu. "A shifting hydrological regime : a field investigation of snowmelt runoff processes and their connection to summer baseflow, Sunshine Coast, B.C." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/31299.
Full textAbstract:
The annual hydrographs in British Columbia rivers are either characterized by glacial, nival, pluvial or “hybrid” (both pluvial and nival) sources of runoff. Climate change scenarios for the 2050s indicate that snow-water-equivalent (SWE) will diminish by 50 to 80% in lower snowfed-dominated basins in the South Coastal region compared to historical values. This could trigger a shift from a hybrid to a pluvial regime for many creeks, including streams used as primary water supply such as Chapman Creek on the Sunshine Coast. It has been suggested in previous studies that this change in runoff regime will negatively impact summer low flows due to an earlier onset of snowmelt and a prolonged summer recession period. However, the connection between groundwater recharge during snowmelt and late-summer water yield remains unclear. A local headwater catchment (Stephen’s Creek) was instrumented and monitored from the fall of 2008 to the fall of 2009. A two- and a three-component isotopic hydrograph separation (2-, 3-IHS) method was developed by adapting the runoff-corrected model (runCE) to a semi-distributed environment in order to account for spatial variability in snowmelt and in isotopic release from the snowpack. IHSs results show that event water (snowmelt) and soil water composed most of the streamflow both at the headwater site (66 ± 19%) and at the mouth (62 ± 23%) during the peak of the freshet, while the contribution of event water to streamflow was significantly different in July (34 ± 11 % at the headwater site vs. 7 ± 4% at the mouth). Hydrometric, isotopic and geochemical data suggest that saturated throughflow was the predominant flow-path taken by melt water during freshet. Preliminary streamflow recession analysis revealed that the snowmelt-recharged headwater catchment can support a steadier summer baseflow than Robert’s Creek – a much larger, but rainfed-dominated watershed. It is concluded that the large input of melt water during the spring was sufficient to “over-turn” the shallow subsurface reservoir of the headwater catchment and recharge deeper flow-paths at a rate that can not be matched by rainfed-dominated systems. The results are of interest to water resource planning in the South Coastal region.
16
Ivkovic, Karen Marie-Jeanne, and kardami@optusnet com au. "Modelling Groundwater-River Interactions for Assessing Water Allocation Options." The Australian National University. Centre for Resources, Environment and Society, 2007. http://thesis.anu.edu.au./public/adt-ANU20080901.134545.
Full textAbstract:
The interconnections between groundwater and river systems remain poorly understood in many catchments throughout the world, and yet they are fundamental to effectively
managing water resources. Groundwater extraction from aquifers that are connected to river systems will reduce river flows, and this has implications for riverine ecosystem
health, water security, aesthetic and cultural values, as well as water allocation and water management policies more generally. The decline in river flows as a consequence
of groundwater extractions has the potential to threaten river basin industries and communities reliant on water resources.
¶
In this thesis the connectivity between groundwater and river systems and the impact that groundwater extractions have on river flows were studied in one of Australias most developed irrigation areas, the Namoi River catchment in New South Wales.
¶
Gauged river reaches in the Namoi River catchment were characterised according to three levels of information: 1) presence of hydraulic connection between aquifer-river
systems; 2) dominant direction of aquifer-river flux; and 3) the potential for groundwater extraction to impact on river flows. The methods used to characterise the river reaches included the following analyses: 1) a comparison of groundwater and river
channel base elevations using a GIS/Database; 2) stream hydrographs and the application of a baseflow separation filter; 3) flow duration curves and the percentage of
time a river flows; 4) vertical aquifer connectivity from nested piezometer sites; and 5) paired stream and groundwater hydrographs.
¶
The theoretical responses for gaining, losing and variably gaining-losing river reaches were conceptualised along with the processes that operate in these systems. Subsequently, a map was prepared for the Namoi River catchment river reaches
indicating aquifer-river connectivity and dominant direction of flux. Large areas of the Upper Namoi River catchment were found to have connected aquifer-river systems,
with groundwater extraction bores located in close proximity to the rivers. Accordingly, the potential for groundwater extraction to impact on river flows in these areas was
considered significant. The Lower Namoi was assessed as having mostly disconnected aquifer-river systems.
¶
In order to investigate the impacts of groundwater extraction on river flows in
connected aquifer-river systems, a simple integrated aquifer-river model entitled IHACRES_GW was developed for use at the catchment scale. The IHACRES_GW model includes a dynamic, spatially-lumped rainfall-runoff model, IHACRES, combined with a simple groundwater bucket model that maintains a continuous water
balance account of groundwater storage volumes for the upstream catchment area relative to the base of the stream, assumed to be the stream gauging station. The IHACRES_GW model was developed primarily: 1) to improve upon existing water
allocation models by incorporating aquifer-river interactions; 2) to quantify the impacts of groundwater extraction on river flows within unregulated, connected aquifer-river
systems; 3) to inform water policy on groundwater extraction; and 4) to be able to utilise the model in future integrated assessment of water allocations options at the catchment scale.
¶
The IHACRES_GW model was applied within the Coxs Creek subcatchment in order to test its validity. The model was used to simulate a range of extraction scenarios which enabled the impacts of groundwater extractions on river flows to be assessed. In
particular, the historical impacts of groundwater extraction on the timing, magnitude and frequency of baseflow events were quantified over a 15-year (1988-2003) simulation period. The IHACRES_GW model was also used to evaluate the implications of water sharing plans for the Coxs Creek subcatchment.
¶
A spatially-lumped modelling approach in the management of water resources has a number of limitations, including those arising from the lack of spatial considerations. However, it offers a number of advantages including facilitating a better understanding
of large-scale water management issues, assessing the impacts of water allocation and groundwater extraction on river flows at the catchment scale, and informing water sharing plans. In particular, this type of modelling approach lends itself to integrated
assessments of water allocation options in which hydrological, ecological and socioeconomic
data sets are combined, and where data is commonly aggregated to a larger scale of interest in response to the requirements of policy makers. The research findings from this thesis provide some insights into how to better manage the impacts of
groundwater extraction in connected aquifer-river systems.
17
Cimino, Joseph A. "Empirical mass balance calibration of analytical hydrograph separation techniques using electrical conductivity." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000213.
Full text
18
Rinaldi, Parisa N. "Relationships Between Landscape Features and Nutrient Concentrations in an Agricultural Watershed in Southwestern Georgia: An Integrated Geographic Information Systems Approach." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/geosciences_theses/59.
Full textAbstract:
This study examined the influence of landscape features on stream nutrient concentrations within the Ichawaynochaway Creek watershed in southwestern Georgia. Baseflow concentrations of both dissolved (SRP, NO3, NH4) and total (TN, TP) nutrients were measured at 17 sampling sites monthly for a period of six months (July 2012 to January 2013). A long-term dataset (January 2008 to March 2012) was also analyzed for baseflow/stormflow comparisons of dissolved nutrient concentrations. Relationships among land-use, geology, soils, physiographic features and nutrients were analyzed at both the sub-watershed and riparian corridor scales. SRP concentrations were lower and NO3 concentrations higher than reported in previous studies of the region. Due to dry conditions during the sampling period, nutrient input was likely limited to groundwater contributions and land-use effects were minimal. Trends among water quality variables varied between the upper and lower portions of the watershed, suggesting differences in nutrient transport pathways due to spatial variation.
19
Cimino, Joseph A. (Joseph Anthony). "Empirical mass balance calibration of analytical hydrograph separation techniques using electrical conductivity [electronic resource] / by Joseph A. Cimino." University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000213.
Full textAbstract:
Title from PDF of title page.Document formatted into pages; contains 75 pages.
Thesis (M.S.C.E.)--University of South Florida, 2003.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
ABSTRACT: Analytical baseflow separation techniques such as those used in the automated hydrograph separation program HYSEP rely on a single input parameter that defines the period of time after which surface runoff ceases and all streamflow is considered baseflow. In HYSEP, this input parameter is solely a function of drainage basin contributing area. This method cannot be applied universally since in most regions the time of surface runoff cessation is a function of a number of different hydrologic and hydrogeologic basin characteristics, not just contributing drainage area. This study demonstrates that streamflow conductivity can be used as a natural tracer that integrates the different hydrologic and hydrogeologic basin characteristics that influence baseflow response. Used as an indicator of baseflow as a component of total flow, streamflow conductivity allows for an empirical approach to hydrograph separation using a simple mass balance algorithm.
ABSTRACT: Although conductivity values for surface-water runoff and ground-water baseflow must be identified to apply this mass balance algorithm, field studies show that assumptions based on streamflow at low flow and high flow conditions are valid for estimating these end member conductivities. The only data required to apply the mass balance algorithm are streamflow conductivity and discharge measurements. Using minimal data requirements, empirical hydrograph separation techniques can be applied that yield reasonable estimates of baseflow. This procedure was performed on data from 10 USGS gaging stations for which reliable, real-time conductivity data are available. Comparison of empirical hydrograph separations using streamflow conductivity data with analytical hydrograph separations demonstrates that uncalibrated, graphical estimation of baseflow can lead to substantial errors in baseflow estimates.
ABSTRACT: Results from empirical separations can be used to calibrate the runoff cessation input parameter used in analytical separation for each gaging station. In general, collection of stream conductivity data at gaging stations is relatively recent, while discharge measurements may extend many decades into the past. Results demonstrate that conductivity data available for a relatively short period of record can be used to calibrate the runoff cessation input parameter used for analytical separation. The calibrated analytical method can then be applied over a much longer period record since discharge data are the only requirement.
System requirements: World Wide Web browser and PDF reader.
Mode of access: World Wide Web.
20
Spahr, Rachel Elizabeth. "Influence of Land Cover, Stream Discharge, and Waste Water Effluent on Suspended Sediment and Nutrient Concentrations in Southwest Ohio Streams." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1561841165531563.
Full text
21
Baloochestani, Farshad. "Estimation of Hydraulic Properties of the Shallow Aquifer System for Selected Basins in the Blue Ridge and the Piedmont Physiographic Provinces of the Southeastern U.S. Using Streamflow Recession and Baseflow Data." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/geosciences_diss/2.
Full textAbstract:
The objectives of this research are to measure the aquifer properties (S, T, and K) of selected watersheds delineated to the U.S. Geological Survey gauging stations using streamflow recession and baseflow data and to describe the relations among the properties of shallow aquifers and the physical properties of the basins, such as slope, regolith type and thickness, and land use type. Geographic Information System (GIS) techniques are utilized to investigate critical physiographic controls on transmissivity and storage coefficients on a regional basis. Moreover, the effect of evapotranspiration on recession index is illustrated. Finally, a detailed quantitative comparison of results for the Piedmont and the Blue Ridge Physiographic Provinces in southeast of the U.S. is provided. Recession index, annual groundwater recharge, and annual baseflow data were obtained from 44 USGS-gauging stations with drainage areas larger than 2 (mi2) and less than 400 (mi2). These gauging stations are located in Georgia and North Carolina. Analyses of data focused on GIS techniques to estimate watershed parameters such as total stream length, drainage density, groundwater slope, and aquifer half-width. The hydraulic diffusivity, transmissivity, and storage coefficient of watersheds were computed using hydrograph techniques and the Olmsted and Hely, and Rorabaugh mathematical models. Median recession index values for the Blue Ridge and Piedmont Provinces are 87.8 and 74.5 (d/log cycle), respectively. Median areal diffusivity values for the Blue Ridge and Piedmont are 35,000 and 44,200 (ft2/d), respectively. Median basin-specific estimates of transmissivity for basins in the Blue Ridge and Piedmont are 150 and 410 (ft2/d), respectively. The large values of transmissivity obtained for the Piedmont regolith may be attributed to the thick regolith, low values of basin relief, and voids that develop as a result of fracturing, foliation, weathering, and fractured quartz veins in the saprolite. Median basin-specific estimates of storage coefficient for basins in the Blue Ridge and Piedmont are 0.005 and 0.009, respectively. In general, the results from this study reveal great differences in basin-specific hydraulic parameters of the regolith material within the Piedmont compared to that of the Blue Ridge Physiographic Province.
22
Kitheka, Bernard M. Mr. "INVENTORY OF STORMWATER MANAGEMENT PRACTICES IN THE CITY OF OXFORD, OHIO." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1274732505.
Full text
23
Beduschi, Carlos Eduardo. "Caracterização isotópica dos componentes do ciclo hidrológico em quatro sub-bacias pertencentes à bacia do Rio Piracicaba (SP)." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-14082008-103438/.
Full textAbstract:
Este projeto teve como objetivo investigar a variação isotópica do oxigênio (?18O) e do hidrogênio (?D) de aqüíferos subterrâneos rasos (não confinados) em quatro regiões onde foram definidas transecções, partindo do canal principal em direção ao topo da vertente. As transecções foram estabelecidas no gradiente topográfico encontrado, em quatro sub-bacias ao longo da bacia hidrográfica do rio Piracicaba. Esta região possui uma população de aproximadamente 3,5 milhões de habitantes e uma economia baseada na agricultura e na indústria. Baseando-se em estudos anteriores sobre a variação isotópica do ?18O e ?D das águas das chuvas e dos rios (Martinelli et al. 2004), onde foi identificada uma sazonalidade nos dados e variações possivelmente associadas à utilização da água em áreas urbanas (uso industrial), os estudos foram estendidos para as fontes de águas subterrâneas (fluxo de base) para o canal principal (rio Piracicaba). A sazonalidade definida por um verão chuvoso (novembro - abril) e inverno seco (maio - outubro) foi coberta com amostragens mensais (final do período seco de 2005; período chuvoso de 2005-2006 e seco de 2006) e quinzenais (período chuvoso 2006-2007) das águas da chuva, de poços rasos, nascentes e rios que drenam as sub-bacias estudadas. Os valores do ?18O e do ?D encontrados na precipitação acumulada entre coletas nas sub-áreas apresentaram maiores variações (extremos; ?18O médio de -0,4 a -13,0? ) quando comparados aos valores das águas superficiais (?18O médio de -5,1 a -9,2? ) e subterrâneas (?18O médio de -6,9 a -7,1? ), sendo que as últimas (poços rasos e nascentes) apresentaram variações ainda menores ao longo do período estudado. A precipitação e o escoamento de base possuem composição isotópica do ?18O relativamente distintas, uma vez que a média ponderada da precipitação (-8,6? observada para o período estudado) foi diferente dos valores médios encontrados nas águas subterrâneas não confinadas (-7,0? em média). O escoamento superficial para o canal principal (rio Piracicaba) teve seu valor isotópico influenciado pela precipitação no período das chuvas (podendo apresentar variações dentro deste período), caso contrário, os sinais isotópicos das águas superficiais seriam mais semelhantes aos sinais isotópicos encontrados no fluxo de base, caracterizando a contribuição deste na manutenção das menores vazões. Contudo, observou-se que o valor médio do ?18O de todos os rios e ribeirões estudados (-5,7? ) foi cerca de 1,2? mais enriquecido do que o valor médio dos poços e nascentes (-6,9? ), no período seco. As amplitudes do ?18O encontradas nxa precipitação e água subterrânea não confinada foram utilizadas em estimativas do tempo de residência médio da água no aqüífero lívre como uma primeira aproximação.This project had the objective to investigate the oxygen (?18O) and hydrogen (?D) isotopic variation of shallow unconfined aquifers in four regions, in transects defined from the river to the limit of the drainage area. The transects were established within a topographical gradient in four sub-catchments of the Piracicaba river hydrographic basin. The population in this basin is almost three and a half millions inhabitants and an economy based on agriculture and industry is responsible for about 10% of the total Brazilian gross production. Based on a well documented isotopic variation of rainwater and river water done previously (Martinelli et al. 2004), where data seasonality and a possible variation related to water use in urban areas were identified, the studies were extended to the groundwater (baseflow) sources to the major channel (Piracicaba river) of the basin. The seasonality defined by a wet summer (november - april) and a dry winter (may - september) was covered with monthly (end of dry season of 2005; rainy season of 2005-2006 and dry season of 2006) and every two weeks sampling (rainy season 2006-2007) of rain water, shallow wells, springs and surface water (rivers) that drain the studied sub-basins. The ?18O and ?D individual values of composite precipitation in the studied sub-areas presented higher variation (extreme values; mean ?18O from -0,4 to -13,0? ) when compared to the values found for surface water (mean ?18O from -5,1 to -9,2? ) and groundwater (wells and springs; mean ?18O from -6,9 a -7,1? ), being the values of groundwater almost constant within the studied period. Precipitation and baseflow have relative different isotopic composition of ?18O, once the weighted average of precipitation (-8,6? observed for the whole studied period) is different from the average values found for unconfined groundwater (-7,0? in average). Values of surface runoff to the main channel (Piracicaba river) were similar to those found in precipitation in the rainy season (presenting variations within this period), otherwise, the isotopic signals of surface water were rather more similar to those found in baseflow, characterizing the contribution of baseflow in the lower flows. However, average value of ?18O of all rivers and streams studied (-5,7? ) were about 1,2? more enriched than the average value of wells and springs (-6,9? ) in the dry season. The amplitudes of ?18O found in precipitation and groundwater were used as a first aproximation to estimate mean residence time of unconfined groundwater.
24
Mingoti, Rafael. "Efeitos da espacialização da cobertura florestal e da profundidade dos solos na produção de água de uma bacia hidrográfica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-25102012-090126/.
Full textAbstract:
Vários trabalhos relacionados ao tema produção de água estão sendo realizados, tendo em comum a associação da cobertura florestal com o escoamento em bacias hidrográficas. Entretanto, não existem estudos onde foram verificados os locais onde esta cobertura tem efeito ótimo, pois, este é dependente das condições edafoclimáticas de cada bacia. O objetivo deste trabalho é avaliar as alterações na produção de água ocasionadas pela posição das áreas com cobertura florestal em relação às de solos rasos em uma bacia hidrográfica. Os estudos foram realizados na Bacia Hidrográfica do Ribeirão dos Marins em Piracicaba, SP, Brasil, por meio da modelagem hidrológica utilizando o modelo distribuído GSSHA. Para a calibração foram utilizados dados meteorológicos, fluviométricos e pluviométricos dos anos de 1999 e 2000, além da obtenção, em laboratório, da condutividade hidráulica e da curva de retenção dos solos da bacia. Foram realizadas sondagens SPT e testes de infiltração de água no solo para determinar a espessura dos solos na bacia e a condutividade hidráulica da zona saturada (lençol freático) desta. A espessura dos solos foi representada por um modelo numérico, elaborado a partir das espessuras medidas e da utilização do modelo HAND. A profundidade do lençol freático foi representada por outro modelo numérico, elaborado a partir da espessura do solo e da profundidade deste lençol medida em campo. Uma nova metodologia que, a partir do coeficiente CN, estima o coeficiente de rugosidade de Manning foi utilizada, apresentando resultados satisfatórios. Nos processos de calibração e validação o modelo apresentou coeficientes de índices de correlação adequados. Foram feitas simulações hidrológicas para 15 anos em três cenários de uso e ocupação do solo, que foram elaborados de modo a comparar uma mesma área de cobertura florestal em diferentes posições da bacia, em função da presença de solos rasos nas proximidades dos cursos d\'água. Foram analisados, entre os cenários para todo o período simulado: o escoamento total e o de base; parâmetros dos hidrogramas (em eventos selecionados da série histórica); posição do lençol freático; umidade do solo; e, curva de permanência. Os resultados permitiram concluir que na área de estudo não há influência da posição da cobertura florestal em relação aos solos rasos para a produção de água. Devido à existência de poucos trabalhos a campo e, também, de modelagem que abordem o efeito da localização da cobertura florestal na produção de água, incentiva-se a realização de novas pesquisas, necessárias, entre outras razões, para a determinação dos locais prioritários a reflorestar ou manter florestado em programas de conservação ambiental.Several works related to the theme of water production are being made, having in common the association of forest cover with runoff in watersheds. However, no studies were found where the places where this land cover has optimum effect, because it is dependent on climatic and physiographic conditions of each watershed. The objective of this study is to evaluate changes in water yield caused by the spatial distribution of forest cover in relation to the shallow soils in a watershed. The studies were conducted in the watershed \"Ribeirão dos Marins\" in Piracicaba, SP, Brazil, through the hydrologic modeling using the distributed model GSSHA. For calibration were used data of meteorological, rainfall and stream flow to the years 1999 and 2000, in addition of the hydraulic conductivity and soil water retention curve obtained in laboratory. SPT tests and water infiltration tests were conducted to determine the thickness of the soils and hydraulic conductivity of the saturated zone (water table) in the watershed. The thickness of the soil was represented by a numerical model, based on those thicknesses measures and the model HAND. The depth of the water table was represented by another numerical model, drawn from the soil thickness and depth of field measured. A new methodology that estimates the Manning coefficient from the CN coefficient was used with satisfactory results. In the processes of calibration and validation of the model, the coefficients showed adequate correlation indexes. Hydrological simulations were made for 15 years in three land cover and land use scenarios, which have been prepared in order to compare the same area of forest cover in different positions of the basin, due to the presence of shallow soils near watercourses. Were analyzed, among the scenarios simulated for the entire period: total flow and baseflow; parameters of hydrographs (in selected events of the series); position of the water table, available water content; and flow duration curves. The results showed that in the study area there is no influence of the position of forest cover in relation to shallow soils to the water yield. Because there are few studies that address the effect of the location of forest cover in water yield is encouraged to conduct further research, among other reasons, for the determination of the priority sites to the reforestation in environmental conservation programs.
25
Drury, Travis Daniel. "Managing a Watershed Inventory Project and Exploring Water Quality Data in the Four Mile Creek Watershed." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1366318507.
Full text
26
Karlsson, Johan, and Hannes Öckerman. "Föroreningar från gata till å : Utvärdering av beräkningsmetod för föroreningsbelastningfrån dagvatten genom en fallstudie i Uppsala." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277033.
Full textAbstract:
Vi lever i ett samhälle med pågående urbanisering. Nyexploateringar och förtätningar istadsmiljöer bidrar till minskad infiltration och evapotranspiration samt ökad ytavrinning avregn- och smältvatten; så kallat dagvatten. Det är viktigt att kvantifiera denna diffusaföroreningskälla i urbana miljöer då bland annat näringsämnen och tungmetaller transporterasmed dagvattnet, vilket bidrar till försämrad status i recipienter. Enföroreningsbelastningsmodell för näringsämnen i dagvatten på nationell nivå används avSvenska miljöemissionsdata (SMED). Beräkningsmetoden använder empiriskt framtagnaavrinningskoefficienter och belastningsschabloner som varierar beroende påmarkanvändningsslag. Flödesproportionell provtagning av totalhalter kväve, fosfor, bly, koppar, zink, kadmium ochsuspenderad substans genomfördes under nio veckor i ett av Uppsalas störstadagvattenavrinningsområden. Syftet var att kvantifiera områdets föroreningsbelastning för attutvärdera och föreslå förbättringar till SMED:s beräkningsmetod som enligt tidigare studierhar stora osäkerheter, men även för att ge underlag till placering av eventuella reningsåtgärderi området. Provtagningen kompletterades med en modellutvärdering där beräkningsmetodenskänslighet med avseende på markanvändning och inkludering av basflöde testades. Även enmer fysikaliskt förankrad modell för näringsämnestransport i naturliga avrinningsområdenanvändes i modellutvärderingen. Resultaten visade att bly, koppar och zink transporteras till Fyrisån i koncentrationer somöverskrider föreslagna regionala riktvärden för dagvatten. För koppar och zink är även dentotala belastningen på recipient högre än tidigare modellerade värden. Då tungmetaller, menäven fosfor, till stor del transporteras i partikulär form bör en eventuell reningsåtgärd iavrinningsområdet fokusera på att avskilja partikulärt material. Åtgärden bör även placerasuppströms industrin GE Healthcare Bio-Sciences AB där föroreningskoncentrationerna spädsut genom att stora volymer kyl- och regenereringsvatten tillförs dagvattennätet. Vidare visade modellutvärderingen att när SMED:s beräkningsmetod applicerades på detstuderade avrinningsområdet överskattades volymavrinningen från dagvattnet jämfört medprovtagningsresultaten medan medelkoncentrationen för kväve underskattades. För fosfor gavprovtagningsresultaten och beräkningsmetoden samstämmiga svar. Sammantagetöverskattade modellen fosforbelastningen något men underskattade kvävebelastningen. Förkväve har basflödet visat sig stå för en betydande del av belastningen och bör därför iframtiden inkluderas i SMED:s beräkningsmetod. Även den markanvändningskarta somanvänds i metoden bör bytas ut på grund av dess inaktualitet samt att modellutvärderingenvisade relativt stora känsligheter i resultaten för ändring i markanvändning.We live in a society with an ongoing urbanization. New development projects anddensifications in urban areas contribute to reduced infiltration and evapotranspiration and anincreased surface runoff from rain and melt water, i.e. stormwater. It is essential to quantifythis diffuse source of pollution in urban environments since nutrients, heavy metals and otherpollutants, are transported by the stormwater and contribute to recipient degradation. Anutrient pollution load model in stormwater is used by Swedish environmental emission data(SMED) on a national level. The SMED computational method utilizes empirical runoffcoefficients and standard concentrations, which vary depending on the catchment land-use. Flow proportional sampling of total concentrations of nitrogen, phosphorus, lead, copper,zinc, cadmium and suspended solids was conducted during nine weeks in one of the largeststormwater catchments in Uppsala city, Sweden. The study aimed at quantifying the pollutionload of the catchment in order to evaluate and suggest improvements to the SMEDcomputational method, which contains large uncertainties according to previous studies.Furthermore, the study aimed at providing a basis for potential treatment measures in thecatchment. The sampling was complemented with a model evaluation where the sensitivity ofthe computational method was tested with respect to land-use input and the inclusion ofbaseflow. The model evaluation also included a comparison with a more physically basedmodel for nutrient transport in natural catchments. The results revealed that lead, copper and zinc are discharged into the Fyris River inconcentrations exceeding proposed regional guideline values. For copper and zinc the totalpollution loads on the recipient are higher than previously modeled values. As heavy metalsand phosphorus are transported largely in particulate form the potential treatment measureshould have the ability to effectively separate particulate matter from the stormwater matrix.Due to emissions of large volumes of cooling and regeneration water from the industry GEHealthcare Bio-Sciences AB, the stormwater pollutants are diluted. The treatment measureshould therefore be placed upstream from the industry. When applying the SMED computational method on the studied catchment, the modeloverestimated the runoff volume from stormwater compared to the sampling results, while theaverage nitrogen concentration was underestimated. Regarding phosphorus concentrations,the model and the sampling results concurred relatively well. This resulted in a higherphosphorus, but lower nitrogen, pollution load predicted by the model. It can partly beattributed the fact that baseflow transport of nitrogen is a significant part of the total pollutionload, and should thus be included in the SMED computational method in future calculations.Another model improvement would be to replace the outdated land-use map currently beingused in the method as the model evaluation indicated a relatively large sensitivity in theresults with regards to alterations in the land-use type input.
27
Bexiga, Anabela da Coceição Rosado. "Qualification of affluent loads to Alqueva-Pedrogão system." Master's thesis, Universidade de Évora, 2008. http://hdl.handle.net/10174/18349.
Full textAbstract:
Este estudo permitiu identificar que em Portugal e Espanha existem inúmeras fontes de poluição urbanas e agrícolas, que contribuíram para a degradação da água do Sistema Alqueva-Pedrógão. As cargas poluentes armazenadas no solo, durante o período seco, foram arrastadas para as linhas de água no período chuvoso. A primeira enxurrada originou o arrastamento de partículas sólidas, do meio terrestre para o meio aquático, provocando um aumento significativo de SST e MO. As cargas de N, P, CB05 e CQO surgiram em maiores quantidades em situações de caudal-base originadas pelas descargas de águas residuais das povoações próximas. A Albufeira de Alqueva alcançou maiores taxas de retenção do que a Albufeira de Pedrógão, no global, o sistema conseguiu retenções consideráveis. Este estudo reforçou a ideia que é necessário, aplicar planos de monitorização sustentáveis nas sub-bacias para minimizar os impactos nas linhas de água e nos reservatórios armazenadores, para conseguir os objectivos da Directiva Quadro da Agua. ABSTRACT; This study allowed the identification of countless punctual urban and agricultural pollution sources that contribute for the water degradation in Alqueva-Pedrógão System both in Portugal and Spain. The flood situation, originated the dragging of solid particles of the terrestrial environment into the aquatic, originating a significant increase of TSS and OM. The loads of N, P, BOD and COO are present ln larger amounts in base-flow situations originated from wastewaters discharges from nearby villages. The Alqueva Reservoir had larger retention rates than Pedrogão Reservoir but, in total, the system presented considerable retention. This study emphasized the idea that there is an urgent need to apply sustainable monitoring plans in the sub-basins, in order to minimize the impacts in the streams and the reservoirs, to achieve the gold's of the Water Framework Directiva.
28
Ilahee, Mahbub. "Modelling Losses in Flood Estimation." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16019/.
Full textAbstract:
Flood estimation is often required in hydrologic design and has important economic significance. For example, in Australia, the annual spending on infrastructure requiring flood estimation is of the order of $650 million ARR (I.E. Aust., 1998). Rainfall-based flood estimation techniques are most commonly adopted in practice. These require several inputs to convert design rainfalls to design floods. Of all the inputs, loss is an important one and defined as the amount of precipitation that does not appear as direct runoff. The concept of loss includes moisture intercepted by vegetation, infiltration into the soil, retention on the surface, evaporation and loss through the streambed and banks. As these loss components are dependent on topography, soils, vegetation and climate, the loss exhibits a high degree of temporal and spatial variability during the rainfall event. In design flood estimation, the simplified lumped conceptual loss models were used because of their simplicity and ability to approximate catchment runoff behaviour. In Australia, the most commonly adopted conceptual loss model is the initial losscontinuing loss model. For a specific part of the catchment, the initial loss occurs prior to the commencement of surface runoff, and can be considered to be composed of the interception loss, depression storage and infiltration that occur before the soil surface saturates. ARR (I. E. Aust., 1998) mentioned that the continuing loss is the average rate of loss throughout the remainder of the storm. At present, there is inadequate information on design losses in most parts of Australia and this is one of the greatest weaknesses in Australian flood hydrology. Currently recommended design losses are not compatible with design rainfall information in Australian Rainfall and Runoff. Also design losses for observed storms show a wide variability and it is always difficult to select an appropriate value of loss from this wide range for a particular application. Despite the wide variability of loss values, in the widely used Design Event Approach, a single value of initial and continuing losses is adopted. Because of the non-linearity in the rainfall-runoff process, this is likely to introduce a high degree of uncertainty and possible bias in the resulting flood estimates. In contrast, the Joint Probability Approach can consider probability-distributed losses in flood estimation. In ARR (I. E. Aust., 1998) it is recommended to use a constant continuing loss value in rainfall events. In this research it was observed that the continuing loss values in the rainfall events were not constant, rather than it decays with the duration of the rainfall event. The derived loss values from the 969 rainfall and streamflow events of Queensland catchments would provide better flood estimation than the recommended design loss values in ARR (I. E. Aust., 1998). In this research, both the initial and continuing losses were computed using IL-CL loss model and a single median loss value was used to estimate flood using Design Event Approach. Again both the initial and continuing losses were considered to be random variables and their probability distribution functions were determined. Hence, the research showed that the probability distributed loss values can be used for Queensland catchments in near future for better flood estimate. The research hypothesis tested was whether the new loss value for Queensland catchments provides significant improvement in design flood estimation. A total of 48 catchments, 82 pluviograph stations and 24 daily rainfall stations were selected from all over Queensland to test the research hypothesis. The research improved the recommended design loss values that will result in more precise design flood estimates. This will ultimately save millions of dollars in the construction of hydraulic infrastructures.
29
Ilahee, Mahbub. "Modelling Losses in Flood Estimation." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16019/1/Mahbub_Ilahee_Thesis.pdf.
Full textAbstract:
Flood estimation is often required in hydrologic design and has important economic significance. For example, in Australia, the annual spending on infrastructure requiring flood estimation is of the order of $650 million ARR (I.E. Aust., 1998). Rainfall-based flood estimation techniques are most commonly adopted in practice.
These require several inputs to convert design rainfalls to design floods. Of all the inputs, loss is an important one and defined as the amount of precipitation that does not appear as direct runoff. The concept of loss includes moisture intercepted by vegetation, infiltration into the soil, retention on the surface, evaporation and loss through the streambed and banks. As these loss components are dependent on
topography, soils, vegetation and climate, the loss exhibits a high degree of temporal and spatial variability during the rainfall event.
In design flood estimation, the simplified lumped conceptual loss models were used because of their simplicity and ability to approximate catchment runoff behaviour. In Australia, the most commonly adopted conceptual loss model is the initial losscontinuing loss model. For a specific part of the catchment, the initial loss occurs prior to the commencement of surface runoff, and can be considered to be composed
of the interception loss, depression storage and infiltration that occur before the soil surface saturates. ARR (I. E. Aust., 1998) mentioned that the continuing loss is the average rate of loss throughout the remainder of the storm.
At present, there is inadequate information on design losses in most parts of Australia and this is one of the greatest weaknesses in Australian flood hydrology. Currently recommended design losses are not compatible with design rainfall information in Australian Rainfall and Runoff. Also design losses for observed storms show a wide variability and it is always difficult to select an appropriate value of loss from this wide range for a particular application. Despite the wide variability of loss values, in the widely used Design Event Approach, a single value of initial
and continuing losses is adopted. Because of the non-linearity in the rainfall-runoff process, this is likely to introduce a high degree of uncertainty and possible bias in the resulting flood estimates. In contrast, the Joint Probability Approach can consider probability-distributed losses in flood estimation.
In ARR (I. E. Aust., 1998) it is recommended to use a constant continuing loss value in rainfall events. In this research it was observed that the continuing loss values in the rainfall events were not constant, rather than it decays with the duration of the rainfall event. The derived loss values from the 969 rainfall and streamflow events of Queensland catchments would provide better flood estimation than the recommended design loss values in ARR (I. E. Aust., 1998). In this research, both the initial and continuing losses were computed using IL-CL loss model and a single median loss value was used to estimate flood using Design Event Approach. Again both the initial and continuing losses were considered to be random variables and their probability distribution functions were determined. Hence, the research showed that
the probability distributed loss values can be used for Queensland catchments in near future for better flood estimate.
The research hypothesis tested was whether the new loss value for Queensland catchments provides significant improvement in design flood estimation. A total of 48 catchments, 82 pluviograph stations and 24 daily rainfall stations were selected from all over Queensland to test the research hypothesis. The research improved the recommended design loss values that will result in more precise design flood estimates. This will ultimately save millions of dollars in the construction of hydraulic infrastructures.
30
Huntington, Justin L. "Evapotranspiration from Irrigated Agriculture and Phreatophyte Shrubs in Nevada, and Role of Surface and Groundwater Interactions on Projected Baseflows in Snow Dominated Regions." UNIVERSITY OF NEVADA, RENO, 2012. http://pqdtopen.proquest.com/#viewpdf?dispub=3490766.
Full text
31
Causse, Jean. "Temporalité des transferts de nutriments dans les bassins versants à algues vertes." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1B012/document.
Full textAbstract:
En Bretagne, les « marées vertes » sont récurrentes depuis le début des années 70 et occupent une place importante dans le débat public en terme sanitaire, politique et économique. Lors de cette thèse, une large revue bibliographique a été réalisée sur l’export d’azote et une méthodologie innovante a été mise en place afin d’étudier la variabilité spatio-temporelle de l’export de nutriments dans 2 bassins versants à algues vertes à une échelle intra-annuelle et pendant des évènements extrêmes (évènements pluvieux, période touristique de basses eaux,…). Les bassins versants sélectionnés pour les expérimentations de terrain sont l’Ic et le Frémur (Côtes d’Armor). 3 types d’expérimentations ont été réalisées sur ces bassins versants : 1) Des campagnes de prélèvements ponctuels par temps sec et par temps de pluie (32 stations, 27 campagnes) ; 2) des prélèvements automatiques en crue (3 stations, 8 crues) ; et 3) la mesure haute fréquence (2 stations, en continu). Les paramètres hydrologiques et physico-chimiques classiques, les matières en suspension, les spectres UV et toutes les formes de macronutriments (carbone, azote, phosphore) ont été analysés lors de ces expérimentations. Les résultats obtenus confirment pour une part un certain nombre de résultats de la littérature. D’autre part, il met en lumière la relation carbone/nitrates, jusqu’à présent peu étudiée à différentes échelles spatio-temporelles et pendant des évènements pluvieux, qui semble pourtant primordiale dans la compréhension des phénomènes d’export de nitrates à l’échelle de l’année. Enfin, l’analyse de toutes les formes de nutriments révèle l’importance des formes particulaires issues de l’érosion des sols. Ces résultats soulèvent de nombreuses questions de recherche qui mériteraient un approfondissement afin d’améliorer la connaissance des transferts de nutriments dans les bassins versants et prioriser les actions de remédiations. Les perspectives de ce travail sont à la fois scientifiques et pratiques. Au niveau scientifique, les efforts de recherche sur la relation carbone/nitrate et l’identification de la fraction de carbone organique assimilable par les organismes dénitrifiants doivent être poursuivis. De même, l’amélioration des connaissances sur l’export de nutriments en crue passe par l’identification précise des sources de nutriments particulaires pendant les crues printanières. Au niveau pratique, il doit contribuer à l’amélioration des pratiques agricoles, à la reconnaissance de l’intérêt des zones humides naturelles et à l’amélioration des types de traitement utilisés par les stations d’épuration. Les résultats obtenus lors de cette étude devraient notamment être mis en relation avec la dynamique des nutriments observée dans l’estran pendant la période de développement des algues vertes. Enfin, un effort d’amélioration de l’accès à certains type de données sur les bassins versants est nécessaire afin d’améliorer la compréhension des transferts de nutrimentsIn Brittany (Western France), "green tides" are recurrent since the early 70s and have an important place in public debate in health, political and economic terms. In this thesis, a wide bibliographic review was performed on the export of nitrogen, and an innovative methodology has been set up to study the spatial and temporal variability of nutrient export in two coastal watersheds on an intra-annual basis and during extreme events (rainfall events, tourist periods of low water, ...). Watersheds selected for the field experiments are Ic and Frémur (Côtes d'Armor). 3 types of experiments were performed on these watersheds: 1) Campaigns of grab samples by dry and wet weather (32 stations, 27 campaigns); 2) automatic sampling during floods (3 stations, 8 floods); and 3) high frequency measurement (2 stations, continuous). Conventional hydrological and physicochemical parameters, suspended solids, UV spectra and all forms of macronutrients (carbon, nitrogen, phosphorus) were analyzed during these experiments. The results confirm in part a number of results of the literature. Furthermore, it highlights the relationship carbon / nitrates far little studied at different spatial and temporal scales and during rainfall events, which however seems to be crucial in understanding of nitrate export. Finally, the analysis of all forms of nutrients reveals the importance of particulate forms from soil erosion. These results raise many research questions that merit further development in order to improve knowledge on nutrient transfers in watersheds and prioritize remediation actions. The prospects of this work are both scientific and practical. At the scientific level, research efforts on the relationship carbon / nitrate and identification of the assimilable fraction of organic carbon by denitrifying organisms must be continued. Similarly, the knowledge on nutrient export must be improved through the precise identification of particulate nutrient sources during the spring floods. On a practical level, it should contribute to the improvement of agricultural practices, the recognition of the interest of natural wetlands and improvement of the types of treatment used by treatment plants. The results obtained in this study should in particular be linked to the dynamics of nutrients in the foreshore observed during the development of green algae. Finally, an effort to improve access to certain types of data on watersheds is needed to improve understanding of nutrient transfers
32
Liu, Hong-Yi, and 劉宏毅. "Baseflow separation using EEMD." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/2qzc56.
Full textAbstract:
碩士國立臺北科技大學
土木與防災研究所
102
Hydrograph representative the sum of two parts-the direct runoff and the baseflow. The direct runoff is formed by a super majority of rainfall infiltration is the primary cause of floods. The baseflow in the river flow is discharged from the drought conditions. The relationship between the hydrological characteristics of river basin and various types of hydrological disasters are very close. Therefore, understanding the hydrological characteristics of the Taiwan’s rivers, and the factors that affect the hydrologic characteristics of Taiwan, is the key to understanding all kinds of hydrological disasters of Taiwan. Taiwan is located at subtropical climate, and between the world''s largest land and largest ocean, the monsoon climate is extremely significant. It’s hot and rainy in summer, and abundant rainfall. However it’s very drought in winter, that makes the gap of Taiwan rivers is enormous between flow and dry season. Different from the past by using empirical mode as the method of baseflow separation, these methods are either too subjective, or non-physical concepts, or inconsistent with the actual hydrological conditions. This study compare the difference between traditional method of base flow separation method, and by using EEMD (Ensemble Empirical Model Decomposition) as the base flow separation in the rainstorm season. We study the flow data of two rivers in northern Taiwan- the Peishih River – Siyuan bridge and Daiyujue River – Dalin bridg. In order to solve the problem of mode mixing, We use the Ensemble Empirical Model Decomposition (EEMD) as a tool for the separation of base flow. If it can be effectively utilized EEMD as the base flow separation in the future, it will be able to do the base flow separation analysis in objectively possessed and physical sense way. It can be a great help both in academic theory or in engineering practices.
33
Hong, Nien-Ming, and 洪念民. "Study of Evapotranspiration and Baseflow Characteristics." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/85646269532534715370.
Full textAbstract:
博士國立臺灣大學
生物環境系統工程學系暨研究所
92
The conceptual models always are used to evaluate the impacts of climate change and climate variation in water resources. Even less parameters in conceptual model are positive, the description of physical become indistinct. For this reason, the study is involved in discussing conceptual models, evapotranspiration and baseflow in watershed. The vertical layers of each conceptual model, often used in hydrology simulation, are compared. The mechanisms of hydrological components in models are discussed. The study of evapotranspiration is to establishment of the conversion coefficients by measuring soil water content in daily time step. Cover coefficient and soil water resistance are included in conversion coefficient. It results that the soil water resistance happens under 35% water content and the cover coefficient is 2.57 in the watershed. On baseflow analysis, a new equation describing the relationship between three successive mean baseflows was derived in this study. There is no time dependent variable, as ground water table and the time of recession. Only a geohydrology parameter is in our equation. Furthermore, nonlinear storage can be describe the decay of baseflow as our equation. Because our equation is developed from groundwater governing equations, the lieanr storage of baseflow in conceptual model can be replaced by nonlinear storage.
34
Chuan-Shun, Yan, and 顏川舜. "Baseflow-Storage Relationships for Small Forest Watersheds." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/08205284278674602513.
Full textAbstract:
碩士國立中興大學
水土保持學系
87
The purpose of this study is to derive relationship between baseflow and storage during dry season for evaluating storage characteristics of watersheds. This study applied linear and curvilinear regression equations to analyze the relationship between daily discharges and storage capacity of Lienhuachi #3, #4, and #5 experimental watersheds of Taiwan Forestry Research Institute in central Taiwan. The results indicated that curvilinear regression equation fitted better for these small and wet watedsheds.The equation between baseflow and storage estimated by curvilinear method in 1981 and 1983 are described as follows: (1) Lienhuachi No.3 experimental watershed Q=0.009837S1.523 （1981） Q=0.010954S1.405 （1983） (2) Lienhuachi No.4 experimental watershed Q=0.000450S2.107 （1981） Q=0.000203S2.258 （1983） (3) Lienhuachi No.5 experimental watershed Q=0.004241S1.727 （1981） Q=0.004853S1.624 （1983） Interception and transpiration will decrease after clearcutting, and watershed storage increase.
35
Hughes, Gregory Owen. "An analysis of baseflow recession in the Republic of South Africa." Thesis, 1997. http://hdl.handle.net/10413/5416.
Full textAbstract:
Demands on the water resources of South Africa are ever increasing owing to population growth
and increased development of urban, peri-urban and rural communities. Problems in terms of
water quantity and quality are likely to be experienced during baseflow recessions. It is therefore
imperative that water resources managers not only understand these baseflow periods of
streamflow, but are able to model them with confidence. Research for this study thus included
a comprehensive literature survey of the factors which affect baseflow as well as the approaches
that previous studies have utilised to analyse and model baseflow recession.
The primary aims of this study were to establish a streamflow database, to construct master
recession curves (MRCs) for each catchment under consideration, evaluate the assumption that
South African rivers recede exponentially, to determine a representative set of catchment
characteristics for use in the baseflow recession analysis, to attempt to explain the MRC trends
using these catchment characteristics and to investigate the feasibility of establishing a rule based
model for baseflow recession.
A streamflow database for South Africa was therefore established. This consisted initially of 202
catchments which were deemed to be recording natural streamflow. MRCs were established for
134 of these catchments. Those MRCs which were established indicate that the majority of South
African rivers do not conform to an exponential model of recession. In order to account for the
trends defined by the MRCs, catchment area, average catchment slope, drainage density, mean
annual precipitation, rainfall concentration, rainfall seasonality, two independent estimates of
groundwater recharge and a geological index were calculated for each catchment. Limited
success was achieved when the data set was divided into subsets in order to group catchments
with similar baseflow recession responses. The geological composition of the catchments
appeared to provide the best results in that those trends exhibited by the MRCs could be explained
by the types and proportions of the lithologies present. Owing to the lack of readily useable
results it was concluded that until further results were forthcoming the development of a rule
based model for baseflow recession analysis in South Africa would be premature. The
establishment of a readily accessible database containing streamflows and associated catchment
characteristics lends itself to future research.Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.
36
Martin, Leslie Ann. "Baseflow turbidity of tributaries to the upper Little Tennessee River, North Carolina and Georgia." 2008. http://purl.galileo.usg.edu/uga%5Fetd/martin%5Fleslie%5Fa%5F200805%5Fms.
Full text
37
Yeh, Yaochun, and 葉耀駿. "A Study on Annual Baseflow Amounts from Small to Medium Sized Headwaters Watersheds in Taiwan." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/80634028644411028636.
Full textAbstract:
碩士國立中興大學
水土保持學系
89
ABSTRACT Groundwater accounts for an important portion of usable water resources. . The objective of this study is to determine the baseflow amount and baseflow index for selected headwaters streams in Taiwan and to derive regression relationships for estimation of baseflow amounts. For discussion purposes, this study partitions Taiwan into four zones (North,Central,South,and East). Based on 39 streamflow data in Taiwan, the results of analyses show that annual baseflow index and value of a given stream generally have little variation (±10%). The variations between streams may be related factors such as elevation、and precipitation，geology and soil texture，vegetation coverage and human development ，uniform of precipitation and evaporation amount. This study derives two baseflow estimation relationships respectively for east and west parts of Taiwan. Eastern Taiwan， Y=0.245*X0(5.076)*X8(1.191)*X9(6.871)*X15(1.687) , Western Taiwan，Y=6.353*X05.623*X81.472*X99.1201*X150.470 (Y:annual baseflow； X0：annual streamflow； X8：watershed average slope；X9：the ratio of relief； and X15：the drainge density of river network) Keywords: base flow, streamflows,baseflow index,multiple regression model,topographic factors.
38
Hill, T. Chee. "Land Cover Change Impacts on Multidecadal Streamflow in Metropolitan Atlanta GA, USA." 2017. http://scholarworks.gsu.edu/geosciences_theses/98.
Full textAbstract:
Urbanization has been associated with the degradation of streams, and a consequence of forest to urban land transition is a change in streamflow. Therefore, the purpose of this thesis is to examine the impacts of land-cover change in ten different watersheds in the rapidly urbanizing Atlanta, GA USA metropolitan area. Streamflow and precipitation data for a 30-year period (1986-2016) were analyzed in conjunction with land cover data from 1992, 2001, and 2011. Big Creek and Suwanee Creek experienced the most urbanization and increases (20%) in streamflow and runoff, and high flow (>95th percentile of flow) days doubled and increased 85%, respectively. Precipitation-adjusted streamflow for Peachtree Creek and Flint River decreased about 17%. Runoff ratios for South River were the highest among all watersheds, even the Etowah River, which remained moderately forested and had the most precipitation and slope.
39
Li, Li. "Frameworks for evaluating and improving simplified hydrologic models for baseflow and rainfall-runoff estimation using distributed physical models." Thesis, 2013. http://hdl.handle.net/2440/95235.
Full textAbstract:
Hydrologic models are becoming increasingly important in the planning, design, operation and management of natural and engineered systems. However, development of such models is complicated by the fact that the underlying physical processes are extremely complex and that the observation and measurement of these processes are expensive and difficult. Consequently, simplified models are generally used in practice for purposes such as baseflow estimation and rainfall-runoff prediction. However, it is difficult to provide a rigorous assessment of how well such simplified models perform under a range of catchment characteristics (e.g. catchment area, soil type, slope) and hydrological inputs (e.g. rainfall, evaporation) and how well they are able to capture the underlying physical processes. In addition, without such assessments, it is difficult to change model structure and parameterization in order to improve the models’ predictive capability and the ability to better represent physical processes. In order to address these shortcomings, in this research, generic frameworks for (i) evaluating and improving recursive digital filters (RDFs) for baseflow estimation and (ii) evaluating the internal dynamic performance of conceptual rainfall runoff (CRR) models are developed and applied. The underlying premise of the frameworks is that fully integrated surface water/groundwater (SW/GW) models are able to provide the best possible approximation to the physical processes of water flow within catchments and can therefore be used as a benchmark against which the performance of these simplified models can be assessed for a variety of physical catchment characteristics and hydrological inputs. The major research contributions are presented in three journal publications. These publications describe: 1) the development of frameworks to evaluate and improve RDF performance for baseflow estimation based on catchment characteristics and hydrological inputs and their application to a single RDF under a limited number of catchment characteristics; 2) the application of the frameworks developed in the first paper to three RDFs under a larger range of catchment characteristics and hydrological inputs, as well as the development of regression equations for predicting RDF performance and optimal RDF parameters for improving RDF performance; and 3) the development and application of framework to evaluate the internal dynamic performance of one commonly used CRR model-Australian Water Balance Model (AWBM) under different calibration regimes under a larger range of catchment characteristics and hydrological inputs. Consequently, this research has developed a new way of evaluating and improving commonly used simplified hydrologic models for baseflow estimation and rainfall-runoff prediction.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2013
40
Zimmerman, Guy Thomas. "Comparison of Baseflow-Stormflow Ion Mass Export for Two Streams in the Great Smoky Mountains National Park." 2011. http://trace.tennessee.edu/utk_gradthes/931.
Full textAbstract:
This study characterizes the mass transport of ions in two streams in the Great Smoky Mountains National Park, comparing transport between stormflow and baseflow periods. By comparing ion mass transport between these two hydrological conditions, the importance of soil and the governing biogeochemical processes will be underscored. Two water quality monitoring study sites were located on the Middle Prong of the Little Pigeon River and Ramsey Prong within the same basin. These remote sites were equipped with YSI 6920 multi-parameter sonde to record continuous 15-min data of pH, depth, conductivity, turbidity, and temperature. Additionally, ISCO 6712 composite samplers were used to collect stream samples during storm events. Baseflow was collected by grab samples prior to storm events, and stormflow collected by ISCO samplers. Throughfall samples were collected after storm events. All samples were analyzed for pH, ANC, and conductivity using an autotitrator. Inductively coupled plasma spectrometry and ion chromatography were used to determine major cations, trace metals, and anions (Ca2+, Na+, K+, Mg2+, Aln+, Cu, Fe, Mn, Si, Zn, SO42-, NO3-, Cl-, NH4+). Stage-discharge relationships were developed at each site utilizing a combination of field measurements and modeling. Velocity and area field measurements were taken to calculate discharges for mid- to low-flow stages while mid- to upper-flow stages were modeled using RIVER2D and verified with field measurements. Stage-discharge curves and sample ion concentrations were used to compute ion mass transport for a two year period in 2006 through 2008. Differences in mass transport of ions between baseflow and stormflow periods found that greater mass transport of ions, except protons, occurred during baseflow periods. These results indicate that on an annual basis ions are stored from input throughfall sources and released gradually through groundwater flow over time more than rapid interflow transport during storm events. This information illustrates the importance of soils and groundwater storage in the regulation of ion transport and streamwater quality in the Great Smoky Mountains National Park.
41
Sadosky, Rebecca Baker. "Physical chemical and biological monitoring and analysis of four small New England watersheds during baseflow and stormflow conditions." 2010. https://scholarworks.umass.edu/dissertations/AAI3409841.
Full textAbstract:
As prolifically documented in the literature, wet weather events have a significant effect on the physical, chemical and biological properties of streams, thereby affecting the overall water quality of the stream as well as the receiving body of water. These effects are of particular importance when the receiving water body is a reservoir used as a source of drinking water in which a decrease in water quality could pose a significant risk to human health. Pathogens such as Cryptosporidium and Giardia are of particular importance to water supply authorities for their specific and direct threat to human health. Cryptosporidium and Giardia are known waterborne pathogens, whose effects on immunocompromised individuals can be life threatening. Because of the risk posed to human health by these pathogens, it is imperative to gain a solid understanding of the environmental factors affecting die-off and transport, and thus the ultimate concentrations in receiving waters. Testing for these pathogens is both expensive and time consuming. It is therefore also important to determine if other, more easily measured parameters can act as surrogates for these pathogens. Documentation of outbreaks resulting from exposure to these resistant pathogens is plentiful and has in part been paralleled by the study described herein. However, this research was necessary owing to the reliance of Southern New England on surface water to supply drinking water to its population and has several focus points that have yet to be evaluated in the existing literature. Specific objectives of this research were to (1) identify and better understand factors affecting Cryptosporidium and Giardia concentrations entering the studied surface water supplies and; (2) develop a sampling protocol for future use by researchers and water utilities to most accurately determine nutrient and microbial concentrations entering a water supply. Factors evaluated included event rainfall, antecedent rainfall, streamflow, land use characteristics, and the validity of indicator organisms to predict the presence of Cryptosporidium and Giardia. The study sites for this research were four small streams in Massachusetts in watersheds with varying land use characteristics. This research focused on gaining a better understanding of the effects of rainfall on in-stream parameter concentrations for streams receiving water running off of areas with distinct land-uses. The effects of rainfall were investigated through field measurements and statistical analyses. The transport of Cryptosporidium and Giardia to receiving waters, as well as understanding the factors impacting their detection, were main focus areas of this research. Study results suggest that the occurrence of Cryptosporidium and Giardia in the tributaries of small watersheds is not easily explained by basic hydrologic conditions, precipitation, land use, or the presence/absence of standard in-stream indicator organisms. Total event rainfall did not significantly affect the presence, absence or concentration of Cryptosporidium or Giardia. However, 72-hr antecedent rainfall totals greater than 20 mm were observed for all but one of the events where Cryptosporidium and/or Giardia were detected. Clostridium perfringens concentrations greater than 100 cfu/100mL was the only water quality parameter (both nutrient as well as microorganism) to provide an accurate indication for the potential presence of Cryptosporidium or Giardia. If present in the near stream area, even small amounts of precipitation when paired with wet antecedent conditions, were likely to result in transport and thus elevated in-stream concentrations of Cryptosporidium and Giardia. Concentrations were typically higher on the rising limb or near the peak of the storm hydrograph, suggesting that the nutrients and microorganisms evaluated were carried into the stream with the first flush. This flushing phenomenon was further evidenced by the clockwise hysteresis loops produced for all events that presented a single peak hydrograph. Cryptosporidium and Giardia were generally (6 out of 7 events) observed at higher concentrations at the downstream sampling location. Occurrence of Cryptosporidium and Giardia in surface waters appeared to be largely a factor of infectivity rates of wild and domesticated animals living within the watershed and their annual cycles. The animal population may have increased the probability of detecting Cryptosporidium or Giardia during the late winter and early spring. For watersheds where reservoirs are the major source of water withdrawals, sampling should be based on hydrodynamics of the reservoir and travel times from the tributaries to the intake. Attention should also be paid to antecedent rainfall conditions and time of year. This dissertation outlines the research objectives, reviews pertinent literature, describes the research design and methods as well as presents results and conclusions.
42
Furtsch, Emily B. "The Effects of Urbanization on Baseflow over Time: An Analysis of Changing Watersheds and Stream Flow Response in Georgia." 2015. http://scholarworks.gsu.edu/geosciences_theses/79.
Full textAbstract:
This study examines the relationship between baseflow and urbanization over time with the help of spatial analysis using Geographic Information Systems. The urbanization parameters used were population and urban land use. Five urban and three non-urban streams were chosen for analysis in the state of Georgia. Four percentile baseflows for each stream were identified and analyzed for trends over time. A correlation analysis was also run to determine how baseflow varies as a function of urbanization. According to the trend analysis, the baseflows over time were considered stable or had no statistically significant trend. The correlation analysis between baseflow and urbanization revealed some scattered relationships though a general conclusion cannot be drawn. The simplicity of the study may have contributed to not capturing all of the baseflow changes with the urbanization parameters.
43
Kent, Christopher Andrew. "The influence of changes in land cover and agricultural land management practices on baseflow in southwest Wisconsin, 1969-1998." 1999. http://catalog.hathitrust.org/api/volumes/oclc/45165194.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1999.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 294-305).
44
Ivkovic, Karen Marie-Jeanne. "Modelling Groundwater-River Interactions for Assessing Water Allocation Options." Phd thesis, 2006. http://hdl.handle.net/1885/49342.
Full textAbstract:
The interconnections between groundwater and river systems remain poorly understood in many catchments throughout the world, and yet they are fundamental to effectively managing water resources. Groundwater extraction from aquifers that are connected to river systems will reduce river flows, and this has implications for riverine ecosystem health, water security, aesthetic and cultural values, as well as water allocation and water management policies more generally. The decline in river flows as a consequence of groundwater extractions has the potential to threaten river basin industries and communities reliant on water resources. ¶ In this thesis the connectivity between groundwater and river systems and the impact that groundwater extractions have on river flows were studied in one of Australia’s most developed irrigation areas, the Namoi River catchment in New South Wales. ¶ Gauged river reaches in the Namoi River catchment were characterised according to three levels of information: 1) presence of hydraulic connection between aquifer-river systems; 2) dominant direction of aquifer-river flux; and 3) the potential for groundwater extraction to impact on river flows. The methods used to characterise the river reaches included the following analyses: 1) a comparison of groundwater and river channel base elevations using a GIS/Database; 2) stream hydrographs and the application of a baseflow separation filter; 3) flow duration curves and the percentage of time a river flows; 4) vertical aquifer connectivity from nested piezometer sites; and 5) paired stream and groundwater hydrographs.
45
MAIEROVÁ, Monika. "Porovnání vybraných metod výpočtu základního odtoku na malém povodí a zhodnocení vlivu základního odtoku na koncentrace dusíku v celkovém odtoku." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-154482.
Full textAbstract:
This thesis is focused on the selected methods of calculating basic runoff on a small catchment basin known as the P6, which belongs to the basin Kopaninsky flow and assess the impact on the basic runoff concentration of nitrate nitrogen in the total runoff. The thesis also analyzes the total, surface and subsurface runoff with its detailed division. There are also described in detail the chosen methods used for the separation of basic drainage. There is shown their mutual comparison too. We dealt with the nitrogen in groundwater. The methods for separation of basic runoff are described with regard to the content of nitrogen compounds, which are practically the most common type of pollution of groundwater used as drinking water sources.
46
ŠVARCOVÁ, Eliška. "Porovnání vybraných metod výpočtu základního odtoku na malém povodí a zhodnocení vlivu základního odtoku na koncentrace fosforu v celkovém odtoku." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-154481.
Full textAbstract:
This thesis is focused on the methods of separation of baseflow and comparing of these metods. It is analyzing concentrations of total phosphorus in the total runoff and influence of baseflow to concentrations of phosphorus in total runoff. The studied area is subcatchment P52 in the catchment Kopaninský flow. Subcatchments P52 is small (64,93 hectares), drained agro-forestry catchment in Českomoravská vrchovina (Czech-Moravian highlands), with a large proportion of forest area (64% forest and 31% of arable land). Studied the period is hydrological period 2009 - 2011. To obtain the necessary results are used daily flow, daily concentrations, daily precipitation of rain gauge station Velký Rybník and monthly precipitation from rain gauge stations of the ČHMŮ (Czech Hydrometeorological Institute) in Humpolec. For the separation of the baseflow and comparison of methods were selected five methods: - method of digital filter according to Chapman (1999), - method UKIH designed by Institute of hydrology (1980), - method RDF proposed by LINE AND Hollick (1979), - method FUKIH proposed by AKOSY AT. AL. (2009) and - method of Kille (1970). All methods are simple to perform and not challenging to input data. When comparing methods, the main problem is that, the results obtained by different methods are very different. Another point of this work is to evaluate the concentrations of total phosphorus in the tatal runoff. Here is analyzed series of daily concentrations of total phosphorus and monthly and annual average concentrations. Low and high concentrations are compared with the values ??of precipitation and clinks are searched between these values. The main problem is that, the concentration of phosphorus are not dependent only on precipitation. The last point is solution of influnence of baseflow to the amount of total phosphorus in the runoff. Here is used the procedure which described BYSTŘICKÝ in its work (2012). There are determined values concentrations typical of baseflow, for direct runoff and total runoff. Groups of values ??are mutually tested and compared. The results show that, the baseflow is negligible contributor of phosphorus to the total runoff, but to achieve more accurate results would be needed to analyse a longer time period (eg 10 years) and compare the results with several different river basins.
47
Price, Kate. "Effects of land use and geomorphology on stream baseflows in the southern Blue Ridge Mountains." 2009. http://purl.galileo.usg.edu/uga%5Fetd/price%5Fkate%5Fm%5F200912%5Fphd.
Full text