The dissertation presents the Global BROOK90 framework, which has been developed at the Chair of Meteorology, TU Dresden by the candidate and co-authors. Global BROOK90 allows modelling the water balance components globally for the local scale of ‘hydrological response units’ in a fully automatic mode. It combines recent advances in global datasets with a physically based model. The framework possesses a vast application range with a special focus on the non-expert users and data scarce regions. To prove the applicability of the framework for different climates, landscapes, soil types and orography, an extensive validation was necessary. Two important components of the water balance – runoff and evaporation– were compared with measured data from all over the globe. Results indicated that considering its build-up and scope, Global BROOK90 performs well on the desired local scale. Certainly, the described approach has substantial shortcomings, thus simulation results must always be treated through the prism of the uncertainties. These limitations result not only from model limitations itself, but also from the input datasets, which were used for parameterization and forcing. Therefore, in this study main uncertainties are addressed allowing the end-user an outlook on their potential impact on the modelling results.

Current climate change poses a threat to the Arctic due to increasing temperatures, which cause the permafrost and glaciers to melt and thaw. This thesis focused on analyzing water balances in Tarfala catchment between 2000 and 2020 and using GIS as a support for tracer test results measured in Tarfala in 2021. The results suggest that high resolution DEM data are more useful compared to low resolution DEM when it comes to understanding local hydrology. In addition, analyses regarding tracer test data suggest that permafrost can act both as a hinder and water flow pathway changer in Tarfala. Water balance calculations show that the area is highly affected by snow, permafrost and climate change and may come to change towards wetter and snow and permafrost free conditions due to climate change. / Den pågående klimatförändringen har en markant effekt på det arktiska ekosystemet på grund av de stigande temperaturerna vilket orsakar permafrosttining. Denna uppsats fokuserade på att analysera vattenbalanser mellan 2000 och 2020 i Tarfalas avrinningsområde samt diskutera hur spårämnesförsök och GIS kan användas för att analysera de lokala förhållandena i områden med permafrost. Resultaten tyder på att högupplöst DEM data kan användas som stöd för spårämnestester som påverkas starkt av jordartssammansättningen och permafrost i Tarfalas avrinningsområde. Resultaten tyder också på att vattenbalans i Tarfala påverkas och har påverkats av flera olika faktorer såsom permafrost, snö och klimatförändringar och kan komma att förändras i framtiden till mer våta samt snö- och permafrostfria förhållanden.

Oil sands mining in Alberta completely transforms the natural boreal landscape of upland forests, wetlands and lakes into open pits, tailings and overburden piles. By law, industry is required to return the landscape to its pre-disturbance land capability. While previous reclamation efforts have mainly focused on upland forest ecosystems, rebuilding wetland systems on soft tailings has only recently become a research focus. The dry, sub-humid climate and high salinity levels of underlying mining material complicate reconstruction of wetlands within this region. In 2012, Syncrude Canada Ltd. completed construction of the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland system to evaluate wetland reclamation strategies. SFW includes an active pumping system, upland hummocks, a fen wetland and underdrains. This study examined the watershed-scale water balance in the first two years after commissioning (2013 and 2014). The first paper presents a semi-distributed water balance approach examining the fluxes and stores of different landscape units. Artificial pumping controlled the water balance in 2013, with approximately double the annual precipitation pumped in and out from May-Oct 2013, causing large water table fluctuations. In 2014, pump management was more passive, and water balance controlled by vertical fluxes. In the second paper, growing season ET rates and controls were assessed using data from three eddy covariance towers in the uplands and lowlands. Average ET rates between uplands and lowlands were similar, with average rates of 2.41 – 2.52 mm d-1. ET was radiatively controlled at all sites. Energy partitioning and ET rates are similar to natural boreal peatlands within the area, however upland areas are expected to increase in ET rates as LAI increases and vegetation matures. This study provides critical quantitative data on the early years of a highly managed watershed. Long-term monitoring is necessary, as water balance dynamics will evolve with vegetation development and climate cycles. / Thesis / Master of Science (MSc)

No description available.

<p>DH31 and drosokinin are known promoters of fluid secretion in <em>Drosophila</em> Malpighian tubules, while the effect of allatostatin A on Malpighian tubule fluid secretion is unknown. The expression of these peptides and their receptors is widespread in the larval gut and central nervous system. The scanning ion-selective electrode technique (SIET) was used to measure changes in epithelial K⁺ flux in the gut as a proxy for the flow of osmotically-obliged water between the gut lumen and the haemolymph. The primary goal of this study was to investigate the effects of DH31 and drosokinin on the gut as an indicator of coordination of diuretic activity between this tissue and the Malpighian tubules. Such coordination, whereby Malpighian tubule fluid secretion is stimulated concomitantly with fluid uptake by the gut, would be physiologically essential for the maintenance of haemolymph volume and osmolarity. Secondarily, this study sought to characterize the function of allatostatin A with respect to its effect on gut K⁺ transport. DH31 stimulated K⁺ absorption across the anterior midgut epithelium and reduced K⁺ absorption in the middle midgut copper cell zone. Drosokinin increased K⁺ absorption across the anterior midgut epithelium and was also stimulatory in the posterior midgut neutral zone. Allatostatin A stimulated K⁺ absorption across the epithelia of the anterior midgut and middle midgut copper cell zone, but was inhibitory in the large flat cell zone. The larger surface area of the anterior midgut relative to the middle midgut means that all three peptides were likely net stimulators of K⁺ uptake. The reduction in K⁺ absorption in the middle midgut by DH31 and allatostatin A may relate to a redistribution of fluid uptake among the regions of the midgut to preserve lumenal pH. DH31 and drosokinin also independently increased the contraction frequency of the anterior midgut, while the contraction frequency of the pyloric sphincter was increased by combined application of both peptides. Stimulation of gut contractions has previously been attributed to these and other diuretic factors in insects. The findings of this investigation implicate DH31, drosokinin, and allatostatin A in the stimulation of midgut K⁺ absorption, which may suggest a role for these peptides in altering fluid transport across this epithelium in larval <em>Drosophila</em>.</p> / Master of Science (MSc)

The design of wetlands to replace those lost to development requires quantitative understanding of the wetland water budget in order to estimate the amount of water available to the wetland over time. Many methods exist to estimate each component of the wetland water budget. In this study, monthly values of the water budget components namely, precipitation, runoff, evapotranspiration, and groundwater seepage were calculated using a water budget model and compared to on-site field measurements for a wetland in Manassas, Prince William County, VA. The monthly precipitation estimated from a weather station 32.18 km from the site differed from the on-site values by as much as 2.9 times. Runoff estimates calculated by the Soil Conservation Service (SCS) method using antecedent moisture condition (AMC) II underpredicted runoff for every month by as high as 100 percent compared to the on-site measured runoff. The choice of AMC greatly affected the SCS runoff estimates. Runoff was the dominant water budget component at the Manassas wetland. The evapotranspiration (ET) estimates using the Thornthwaite method either over or underestimated ET when compared to ET calculated from diurnal cycles of the water table in the wetland. Groundwater seepage losses were calculated using Darcy's equation with an assumed hydraulic gradient of one, and with gradients measured with nested piezometers. Seepage losses at the Manassas wetland were negligible. Overall, the water budget model provided conservative estimates of the available water in the wetland during the 10-month period of observation. / Master of Science

Monthly water balance models are important tools for hydrological impact assessment of climate change. Traditionally monthly models adopt a conceptual, lumped-parameter approach. Based on an extensive survey and review of existing monthly water balance models, six models with different conceptualization and structure, i.e., Thomthwaite-Mather, Belgium, Xinanjiang, Guo, WatBal and Schaake, were compared through calibration and validation using observed data of hydrology and climate of 1960-1988 in the Dongjiang basin. The model comparison offered insights for the development of a monthly distributed model which integrates the spatial variations of basin terrain and rainfall into runoff simulation. An innovative feature of the new model is that the spatial distribution of soil moisture capacity which is described as a parabolic curve in Xinanjiang model is represented by a cumulative frequency curve of index of relative difficulty of runoff generation based on the concept of topographic index in TOPMODEL. The calibration and validation results show that the developed model with only three parameters is suitable for monthly runoff simulation in the Dongjiang basin. / The developed model was applied to evaluate the changes in water availability in the Dongjiang basin under hypothetical climate change scenarios and those derived from projections of three General Circulation Models (GCM), i.e., CGCM1, CSIRO and ECHAM4. Sensitivity analyses based on hypothetical scenarios suggest that climatic change has greater effects on runoff than on soil moisture and greater effects on water availability in dry months than in wet months. The effects of precipitation changes on the amount of runoff and soil moisture can be characterized by a magnification factor whereas temperature increases alone produce negligible effects. Hydrological simulation with inputs of three GCM-generated scenarios indicates that annual and rain-season runoff will increase by 0.3&deg;io to 13.9% and 7.6% to 12.0%, respectively, by the 2050s. Dry-season runoff will change between -23.2% and +26.4%. Average annual and dry-season soil moisture will decrease by 1.3% to 6.9% and 1.0% to 8.1%, respectively. Soil moisture will demonstrate little change in rain-season. Increase in annual runoff and reduction in annual soil moisture will be apparent over the whole basin, but there is relatively little consistency among the three GCM-generated scenarios as to the magnitudes of spatial change in runoff and soil moisture. Although these results are not definitive statements as to what will happen to runoff and soil moisture in the Dongjiang basin, they rather have significant implications for the study of response strategies of water supply and flood control to climate change. / Jiang Tao. / "July 2005." / Advisers: Chen Yongqin; Lam Kin-che. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0149. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 174-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / School code: 1307.

Master of Science / Department of Civil Engineering / David R. Steward / The Ogallala Aquifer is a supply of water for several municipalities in western Kansas, as well as an irrigation source for local farmers. Since the 1950’s, when the aquifer started to be pumped for irrigation, the region has seen steady declines of the groundwater table. These declines have reduced stream flow in the Arkansas and Cimarrron Rivers, and caused a redistribution of riparian phreatophytes. This thesis studies this redistribution of phreatophytes, and develops statistical relationships relating a phreatophyte’s location to depth to groundwater, increase in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine tree locations on predevelopment and post-development aerial photography. These locations were mapped using ArcGIS, and ArcAEM was used to model groundwater flow in six riparian regions taking root uptake into account. It was found that once the depth to groundwater becomes greater than about 3 m, tree population will decrease as depth to water increases. Trees were located within 700 m of the river. Areas with a dense tree population (>10% tree cover) occurred where the average depth to water ranged from 0.24-1.4 m. Areas with moderate tree density (5-10% tree cover) corresponded to an average depth to water ranging from 2.1-19 m. Areas with a low tree density (<5% tree cover) corresponded to an average depth to water ranging from 11-28 m. It was found that phreatophytes have a high likelihood of growing on hydrologic soil group A and a low likelihood of growing on hydrologic soil group B. The number of trees located on hydrologic soil group D was what would be statistically expected if tree location were independent of soil type. It was also found that tree locations could be used as an indicator of good hydraulic connectivity between surface water and groundwater. This information can be used to help guide future installation of monitoring networks and expand research projects from central Kansas to western Kansas.

Warmer air temperatures projected for the mid-21st century under climate change are expected to translate to increased evaporation and a re-distribution of precipitation around the world, including in the mid-latitude, continental Athabasca River region in northern Alberta, Canada. This study examines how these projected changes will affect the water balance of various lake sizes. A thermodynamic lake model, MyLake, is used to determine evaporation over three theoretical lake basins – a shallow lake, representative of perched basins in the Peace-Athabasca Delta near Fort Chipewyan; an intermediate-depth lake representative of industrial water storage near Fort McMurray; and a deep lake representative of future off-stream storage of water by industry, also near Fort McMurray. Bias-corrected climate data from an ensemble of Regional Climate Models are incorporated in MyLake, and the water balance is completed by calculating the change in storage as the difference between precipitation and evaporation. Results indicate that evaporation and precipitation are projected to increase in the future by similar magnitudes, thus not significantly changing the long-term water balance of the lakes. However, intra-annual precipitation and evaporation patterns are projected to shift within the year, changing seasonal water level cycles, and the magnitudes and frequencies of extreme 1-, 3- and 5-day weather events are projected to increase. These results demonstrate that future climate change adaptation and mitigation strategies should take into account increases in intra-annual variability and extreme events on water levels of lakes in mid-latitude, interior hydroclimatic regimes. / Graduate / 0368 / walkerg@uvic.ca

Hyaluronan (HA) is a negatively charged extracellular matrix (ECM) component with water-attracting properties. It is the dominating ECM component in the renal medullary interstitium, where the amount changes in relation to hydration status: it increases during hydration and decreases during dehydration. It has, therefore, been suggested that HA participates in the regulation of renal fluid handling by changing the permeability properties of the interstitial space. This thesis investigates potential mechanisms for such a role in renal fluid regulation. The results demonstrate that the high renal HA content of late nephrogenesis decreases during the completion of kidney development in the rat, which takes place in the neonatal period. The heterogenous distribution of HA is mainly established during the first three weeks after birth. On day 21, the HA content is similar to that in the adult rat. The process is dependent on normal Ang II function. It primarily involves a reduction of HA synthase 2 expression and an increase of medullary hyaluronidase 1.  The cortical accumulation of HA that results from neonatal ACE inhibition can partly explain the pathological condition of the adult kidney, which causes reduced urinary concentration ability and tubulointerstitial inflammation. It is possible to reduce renomedullary HA with the HA synthesis inhibitor 4-MU, and the kidney’s ability to respond to a hydration challenge will then be suppressed, without affecting GFR.  The investigation of renomedullary interstitial cells (RMIC) in culture, shows that media osmolality and hormones of central importance for body fluid homeostasis, such as angiotensin II, ADH and endothelin, affect HA turnover through their effect on the RMICs, in a manner comparable to that found in vivo during changes in hydration status.  In established streptozotocin-induced diabetes, HA is regionally accumulated in the kidney, proteinuria and polyuria, reduced urine osmolality, and reduced response to ADH V2 activation will occur. As opposed to the proteinuria, the HA accumulation is not sensitive to mTOR inhibition, suggesting an alternate pathway compared to other ECM components  Taken together, the data suggest that during normal physiological conditions, renomedullary interstitial HA participates in renal fluid handling by affecting the interstitial prerequisites for fluid flux across the interstitial space. This is possible due to the water-attracting and physicochemical properties of this glycosaminoglycan. During pathological conditions, such as diabetes, the elevated interstitial HA can contribute to the defective kidney function, due to the proinflammatory and water-attracting properties of HA.